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Summary of the 2023 Ocean Surface Topography Science Team Meeting


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Summary of the 2023 Ocean Surface Topography Science Team Meeting

Severine Fournier, NASA/Jet Propulsion Laboratory, severine.fournier@jpl.nasa.gov
Joshua Willis
, NASA/Jet Propulsion Laboratory, joshua.k.willis@jpl.nasa.gov

Introduction

The annual Ocean Surface Topography (OST) Science Team Meeting (STM) provides a forum for the international altimetry community to foster collaboration, address specific issues, and highlight scientific results and applications every year. The meeting location alternates between Europe and the U.S. The 2023 meeting was held in San Juan, Puerto Rico, from November 7–11, 2023. About 130 registrants from more than a dozen different countries attended the meeting.  

During this meeting the OST Science Team addressed specific technical issues related to the reference altimetry missions, which include the Ocean Topography Experiment (TOPEX)–Poseidon (1992–2006), Jason-1 (2001–2013), Ocean Surface Topography Mission (OSTM)/Jason-2 (2008–2019), Jason-3 (2016–present), and Sentinel-6 Michael Freilich (S6MF; 2020–present) missions. There was also discussion about the upcoming Sentinel-6B mission (scheduled for launch in 2025), which will be a successor to S6MF. The technical issues addressed included algorithm and model improvement, calibration/validation (cal/val) activities, merging TOPEX–Poseidon–Jason–S6MF data with those from other altimetric satellites, initial results from the Surface Water and Ocean Topography (SWOT) mission (2022–present), and preparation for future OST missions (e.g., Sentinel-6B).

The remainder of this article provides an overview of the meeting content, then presents an update on the status of current and planned OST missions, followed by a summary of the opening plenary and a couple of the most relevant science highlights from the splinter sessions. More details are available in the full report from the OST STM. The full OST STM program lists all of the presentations from the plenary, splinter, and poster sessions as well as links to many of the presentations and abstracts for the posters.

Meeting Overview

The meeting began with an opening plenary session, followed by an invited presentation, a series of splinter sessions, and a closing plenary session. The splinter session topics spanned a variety of algorithm improvements and measurement uncertainties, as well as sessions on coastal altimetry, the Chinese–French Oceanography Satellite (CFOSAT) mission (2019–present), and science topics ranging from climate and oceanography to hydrology and cryosphere science. A complete list of splinters is available online. Some of these are described in more detail in the sections that follow.

Status Report on Current OST Missions

This section reports on the status of several current and planned OST-related satellite missions. Each is described in its own subsection.

Sentinel-6 Michael Freilich

S6MF, launched on November 21, 2020, from Vandenberg Space Force Base, successfully completed its commissioning and subsequent entry into routine operations on schedule, one year later. S6MF succeeded Jason-3 as the Reference Mission (i.e., the mission that other altimetry missions are compared to) on April 7, 2022, at which point Jason-3 vacated the reference orbit. The first full mission reprocessing of products was released in July 2022, and another full reprocessing was completed in July 2023.

Jason-3

Jason-3, launched on January 17, 2016, continues its extended mission and is fully operational with all redundant systems available. It completed a longer than initially planned 15-month tandem phase with S6MF, which allowed for calibrations of both the primary and redundant instruments. On April 25, 2022, it began operations in an orbit that optimally interleaves ground tracks with S6MF. A second tandem phase with S6MF has been requested for early 2025. The second tandem phase aims to place an uncertainty bound on any long-term drift between the two missions.

Copernicus Copernicus Sentinel-3A and -3B

Sentinel-3A and -3B are identical satellites that were launched in February 16, 2016 and April 25, 2018, respectively. Similar to past missions in the reference orbit, a tandem phase with a separation of 30 seconds between the two satellites was performed to provide cross-calibration. Subsequently, Sentinel-3B was placed in a nominal orbit 140° out of phase with Sentinel-3A. Both missions now provide sea level measurements along high inclination tracks as part of their routine operations. A full mission reprocessing of land altimetry Level-2 (L2) products was completed in 2023.

Copernicus Sentinel-6B and 6C Missions and Beyond

Identical to S6MF, Sentinel-6B is planned as its successor. The spacecraft and instrument have been completed and is now in storage awaiting launch in 2025. Sentinel-6B will assure operational continuity through the end of 2030. An additional satellite, Sentinel-6C, is under consideration by NASA, the National Oceanic and Atmospheric Administration (NOAA), the European Organization for the Exploitation of Meteorological Satellites (EUMETSAT), the European Space Agency (ESA), and the Centre National d’Études Spatiale (CNES) [French Space Agency] to continue observations through 2035.

Surface Water Ocean Topography

SWOT launched on December 16, 2022. The primary instrument on SWOT, Ka-band radar interferometer (KaRIn), is the first space-borne, wide-swath altimetry instrument, capable of high-resolution measurements of the water height in the ocean and freshwater bodies. After commissioning and initial calibration, beta products became available to the science team in August 2023. The first images from SWOT were released, and the first results are showing great promise for the instrument capabilities (see NASA and CNES news).

Discussion of Future Missions Relevant to OST

The meeting continued with presentations on several existing and upcoming missions in various stages of development, each with applications relevant to OST. Each presentation included information on the mission’s status and development plans, as described below.

Copernicus Polar Ice and Snow Topography Altimeter (CRISTAL)

Copernicus Polar Ice and Snow Topography Altimeter (CRISTAL) is one of six, high-priority candidate Copernicus Sentinel Expansion missions that are being studied to address the European Union’s needs, as well as to extend the current capabilities of the Copernicus space components. CRISTAL will carry a multifrequency radar altimeter and microwave radiometer to ensure continuity and improve the quality of sea ice thickness measurements compared to its predecessor, Cryosat-2, and provide the first space-based measurements of overlying snow depth.

Recommendations from the OST Science Team

After discussing these missions and other issues concerning altimetry, the OST STM adopted several recommendations to particular topics relating to these missions, which are named and described in the subsections that follow:

S6MF Extended Operations Phase Orbit.  

In light of that fact that user needs remain very high for altimetry observations complementary to the reference mission, the OST ST recommends extending operations of S6MF – assuming it remains in good health – beyond the time when Sentinel-6B has become the reference mission. Specifically, the OST ST recommends:

  • Moving S6MF to an exact repeat orbit with the same characteristics as the reference orbit – except for a phase difference of 163° along the orbit, either ahead or behind Sentinel-6B – resulting in an interleaved ground-track to the reference orbit. (For reference, Jason-3 currently flies 163° behind S6MF.)
  • Adopting the same data availability requirements as expressed in the End-User Requirements Document (EURD) (R-U- 00460/490/500/515/520/570/573/576) for the extended operations phase of S6MF, with the understanding that Sentinel-6B operations will be prioritized over S6MF.

Jason-3 Orbit Change.

The OST ST endorses the current plan to move Jason-3 to a Long Repeat Orbit (LRO) immediately after the conclusion of second tandem with S6MF. This 371-nodal-day LRO should be the same as the one occupied by Jason-2. The first two LRO cycles should be phased such that Jason-3 will interleave the two Jason-2 LRO cycles, each shifted by 2 km (1.2 mi). This will result in a systematic 2-km global grid combining Jason-2 and Jason-3 LRO data. The OST ST also recommends two additional LRO cycles that revisit the Jason-2 LRO ground tracks to fill in gaps and reduce mean sea surface errors. 

Climate Quality Accuracy in Future Mission 

To achieve accuracy in global and regional sea level change as detailed in the Global Climate Observing System (GCOS) requirements, the OST ST noted that it will be necessary to maintain and continue to improve the accuracy of orbital determination systems, such as those achieved using a combination of three tracking systems – Satellite Laser Ranging [SLR], Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS), and Global Navigation Satellite System [GNSS]). The OST ST has demonstrated that these tracking systems are necessary to achieve maximum accuracy on the determination of regional sea level trends and strongly recommends that such accuracy be maintained in the design of Sentinel-6C. The OST ST also noted that accuracy of the Climate Data Record requires continued maintenance or improvement of the terrestrial reference frame, which also relies on these tracking systems. Finally, requirements on other aspects of the altimetric measurement system must also be maintained or continue to improve. 

Synergies with Argo and GRACE 

Argo (which is an international fleet of robotic instruments that drift with the ocean currents and measure the temperature and salinity of the ocean) plays a critical role in collecting data related to numerous cross-cutting, climate-related science topics important to altimetry measurements (missions discussed earlier in this article), to gravity measurements [e.g., the Gravity Recovery and Climate Experiment (GRACE) and GRACE-Follow-On missions], and to broader science communities. The recent implementation of the Deep Argo mission has rapidly expanded observations of the ocean below 2000 m (~6500 ft). Data collected at these depths has helped to resolve questions about variations of temperature and salinity over the full depth of the ocean and to close regional and global sea level budgets. The OST ST recommends substantially increasing support for the OneArgo Program (which has been part of Argo’s design plan since 2020), including adding resources to expand the array to include global implementation of Deep Argo and increase coverage by Core Argo (the fleet of shallower floats) in polar regions and marginal seas. 

Altimetry Product Evolution 

OST ST recommends that agencies study the performance of the three latency products – Near Real-Time (NRT), Short Time-Critical (STC), and Non-Time Critical (NTC) – to ensure each continues to meet user needs or determine if their performance and latencies be redefined or adjusted. This should be considered across all platforms. 

Potential Gap between CryoSat-2 and CRISTAL 

The OST ST recommends studies to address which satellites, airborne operations, or other assets might help fulfill scientific needs for high-latitude ocean and ice elevation measurements during a potential gap between CryoSat-2 and CRISTAL. The OST ST also recommends minimizing the probability of a gap by extending CryoSat-2 operations through at least 2028 and avoiding delays in the launch of CRISTAL to the extent possible. 

Integrity of the Altimetry Constellation and Instrument Function 

 In light of ongoing efforts to launch a large number of communications satellites in orbits close to the 1336 km (830 mi) altimetry constellation, the OST ST recommends that agencies take steps to determine and establish sufficient margins that will safeguard altimetry missions in both reference and polar orbits from collision, debris, and interference with their passive and active instruments.

Opening Plenary Session Highlights

Severine Fournier [NASA/Jet Propulsion Laboratory (JPL)] began with welcoming remarks on behalf of all of the project scientists, who (in addition to herself) include Josh Willis [NASA/JPL], Pascal Bonnefond [CNES], Eric Leuliette [NOAA], Remko Scharroo [EUMETSAT], and Alejandro Egido [ESA]. In particular, Fournier reminded the participants of the addition of online forums, available until the next OST STM that can be accessed after logging into the site. In addition, Fournier announced that Egido will replace Craig Donlon as the ESA Project Scientist.

Program managers gave presentations on the status of altimetry and oceanographic programs at their respective institutions including: Nadya Vinogradova-Shiffer [NASA Headquarters], Annick Sylvestre-Baron [CNES], Estelle Obligis [EUMETSAT], Eric Leuliette, and Jérôme Bouffard [ESA].

In addition, Josh Willis presented Space Stories, a think tank for U.S.-based creatives and technologists to develop new storytelling approaches to sea level rise. This initiative is organized by Garage Stories and consists of masterclasses that were held in November 2023 with 15 participants across 5 teams. The winning team will have the opportunity to present their concept at JPL in 2024.

Finally, Fernando E. Pabón [Caribbean Center for Rising Seas—Director] spoke about climate issues that impact Puerto Rico. The island has about three million inhabitants and faces several climatic issues, including devastating impacts from hurricanes (with a hurricane season stretching over six months every year), sea level rise, and droughts. While Puerto Rico has a lot of outdated infrastructures, the territory has the most advanced regulatory environment in the Caribbeans. Pabón explained the economic, social, and geographical urgency of making good decisions to help the communities facing climatic challenges with a long-term vision. One of the goals of the Caribbean Center for Rising Seas is to work with practitioners and the public to change urban development practices, update building codes, zoning, and land-use regulations and spread the knowledge and understanding of sea level rise and flooding to the public.

Science Highlights

This section provides two scientifically compelling results that were shown during the splinter sessions. Complete coverage of the results shared during these sessions can be found at the website at the start of the article.

Synergies between Argo, GRACE, and Altimetry

Human activities are increasing the concentration of greenhouse gases, which have increased global temperature since the beginning of the twentieth century. Greenhouse gases trap energy within the Earth system. The ocean absorbs much of this excess energy in the form of heat (> 90%), acting as a huge heat reservoir. Global ocean heat content (GOHC) is therefore a key component in the Earth’s energy budget. Accurate knowledge of the GOHC change allows us to assess the Earth Energy Imbalance (EEI), which refers to the difference between the amount of energy the Earth receives from the Sun and the amount of energy it radiates back into space.

Various methodologies exist to estimate EEI from the GOHC. A 2022 article in Earth System Science Data describes the space geodetic approach, which relies on satellite altimetry and gravimetry measurements. Satellite altimetry is used to measure sea level rise, which is caused by both the expansion of warming ocean waters and the addition of freshwater to the ocean from melting land ice (Greenland and Antarctic ice sheets and mountain glaciers). Gravimetric measurements are used to measure ocean mass change, which can be used to estimate the contribution to sea level rise from freshwater ice melt on land. By combining gravimetry and altimetry, it is possible to estimate the thermal expansion of the entire ocean and scale it to estimate EEI – see Figure 1. The magnitude of EEI is small (0.5–1.0 W/m2) compared to the total amount of energy entering and leaving the climate system (~340 W/m2). Therefore, a high level of precision and accuracy are required to estimate the EEI mean (2) and its time variations at decadal scales (2). In this regard, the space geodetic approach emerges as a promising candidate capable of complementing other observing system elements aimed at measuring EEI.

OST Figure 1
Figure 1. This graph shows the decadal variations of the Earth Energy Imbalance (EEI) estimated from the space geodetic method that combines altimetry and gravimetric measurements (black) and direct measurements of solar radiation at the top of the atmosphere from the Clouds and the Earth’s Radiant Energy System (CERES) instrument (blue). The grey shaded area corresponds to the space geodetic method’s uncertainty.
Image credit: Michael Ablain/Collect Localisation Services (CLS), France

Large-scale Ocean Circulation Variability and Change

The year-to-year circulation changes along the coast of the western U.S. can have significant impact on the transport of nutrients that affect fisheries. A 2021 article published in the journal Limnology and Oceanography described a study that used ocean currents derived from satellite altimetry to understand the trajectory of water masses from the southern coast of California to the Pacific Northwest. The results show that after a year, subtropical/tropical water masses can reach the Oregon coast from the Southern California Bight (30 °N), and in multiple years from even further south (~26 °N–27 °N) and west. During warmer than average years associated with El Niño Southern Oscillation (1997–1998, 2002–2003, 2004–2005, 2005–2006, 2009–2010, 2014–2015, 2015–2016, 2016–2017), these subtropical/tropical waters masses reached further north compared to other years – see Figure 2. This shift is due to the increase poleward wind stress observed in the California Current. The research team also showed that these tropical warm waters tend to transport “warm water” zooplankton species with a lower fat content. The shift in zooplankton species can impact the young salmon population, which prefer fatty cold-water zooplankton, entering the ocean off the Oregon coast.

OST Figure 2
Figure 2. This graph shows the density of the water mass traveling northward from the tropics and sub-tropics toward the Pacific Northwest coast during [first three panels] the average of Warm Years (1997–1998, 2002–2003, 2004–2005, 2005–2006, 2009–2010, 2014–2015, 2015–2016, 2016–2017) for January, February, and March, and [last three panels] normal, or Other Years (remaining 15 years excluded from the ‘warm year episodes’ between 1997–2020) for January, February, and March. Off the coast of Oregon, warm water masses are denser during warm years.
Image credit: Ted Strub/Oregon State University

Closing Plenary Session Highlights

The closing plenary session included discussions, notably about the key points that were addressed during the opening session and splinter sessions.

Cristina Martin-Puig [EUMETSAT] gave a presentation on the definition of the new Geophysical Data Record (GDR) standards (GDR-G) in a multimission context. There are currently 11 altimeters operating with data quality that continues to undergo improvement. While agencies have been coordinating to homogenize processing baselines across missions, a full harmonization between missions was never discussed in detail until now. All agencies are now working in full collaboration to define a set of common standards and the best data processing practices to ensure full harmony between missions.

Conclusion

During the closing session, the OST ST adopted several recommendations – see “Recommendations from the OST Science Team” above for details.

The OST STM expressed strong support for the continuation of the joint Indo–French Satellite AltiKa (SARAL) drifting period for as long as possible, with its altimeter being the most important for future improvements in mean sea surface and gravity.

The OST STM ended with acknowledgements and kudos, several of which refer to recommendations made by the OST ST. The team expressed its appreciation to NASA and CNES for the successful launch and commissioning of the SWOT mission and its revolutionary new wide-swath altimeter for ocean and surface water. Additional acknowledgements can be found in the full OST STM report link referenced in the introduction of this article.

Overall, the meeting fulfilled all of its objectives. It provided a forum for updates on the status of Jason-3, S6MF, and other relevant missions and programs. It also offered detailed analyses of mission observations by the splinter groups. The team concluded that data from the Jason-3 and S6MF altimeters continue to meet the accuracy and availability requirements of the science community.

An international altimetry meeting to celebrate the 30-year anniversary of altimetry will be held in Montpellier, France on September 2–7, 2024.

separater line

Acknowledgment: This article is based on the official meeting report, referenced in the introduction of this article and prepared in cooperation with all of the OST STM chairs: Severine Fournier [JPL]; Josh Willis [JPL]; Pascal Bonnefond [Observatoire de Paris, Laboratoire Systèmes de Référence Temps-Espace (SYRTE)/CNES]; Eric Leuliette [NOAA]; Remko Scharroo [EUMETSAT]; and Alejandro Egido [ESA].

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Last Updated
May 31, 2024

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      Matsunaga also highlighted the importance of ground-based validation networks, such as the Total Carbon Column Observing Network, COllaborative Carbon Column Observing Network, and the Pandora Global Network, to ensure satellite data accuracy.
      Son Nghiem [NASA/Jet Propulsion Laboratory (JPL)] addressed dynamic LUCC in Cambodia, Laos, Thailand, Vietnam, and Malaysia. The synthesis study examined the factors that evolve along the rural–urban continuum (RUC). Nghiem showcased this effort using Synthetic Aperture Radar (SAR) data from the Copernicus Sentinel-1 mission to map a typical RUC in Bac Lieu, Vietnam – see Figure 2.
      Figure 2. Land cover map of Bae Lieu, Vietnam, and surrounding rural areas. The image shows persistent building structures (red), agricultural areas (light green), aquacultural (light blue), tree cover (dark green), and water bodies (dark blue). Land-use classes used on this map are derived from Sentinel-1 Synthetic Aperture Radar (SAR) for the rural urban continuum around Bac Lieu. Figure credit: Son Nghiem [JPL] Nghiem described the study, which examined the role of rapid urbanization, agricultural conversion, climate change, and environment–human feedback processes in causing non-stationary and unpredictable impacts. This work illustrates how traditional trend analysis is insufficient for future planning. The study also examined whether slower or more gradual changes could inform policy development. To test these hypotheses, his research will integrate high-resolution radar and hyperspectral data with socioeconomic analyses. The study highlights the need for policies that are flexible and responsive to the unique challenges of different areas, particularly in “hot-spot” regions experiencing rapid changes.
      Peilei Fan [Tufts University] presented a study that synthesizes the complex patterns of LUCC, identifying both the spatial and temporal dynamics that characterize transitions in urban systems. The study explores key drivers, including economic development, population growth, urbanization, agricultural expansion, and policy shifts. She emphasized the importance of understanding these drivers for sustainable land management and urban planning. For example, the Yangon region of Myanmar has undergone rapid urbanization – see Figure 3. Her work reveals the need for integrated approaches that consider both urban and rural perspectives to manage land resources effectively and mitigate negative environmental and social impacts. Through a combination of case studies, statistical analysis, and policy review, Fan and her team aim to provide a nuanced understanding of the interactions between human activities and environmental changes occurring in the rapidly transforming landscapes of Southeast Asia.
      Figure 3. Landsat data can be used to track land cover change over time. For example, Thematic Mapper data have been used to track urban expansion around Yangon, Myanmar. The data show that the built-up area expanded from 161 km2 (62 mi2) in 1990 to 739 km2 (285 mi2) in 2020. Figure credit: Peleli Fan [Tufts University] Session III: Land Cover/Land Use Change Studies
      Tanapat Tanaratkaittikul [Geo-Informatics and Space Technology Development Agency (GISTDA), Thailand] highlighted GISTDA activities, which play a crucial role in advancing Thailand’s technological capabilities and addressing both national and global challenges, including Thailand Earth Observation System (THEOS) and its successors: THEOS-2 and THEOS-2A. THEOS-1, which launched in 2008, provides 2-m (6-ft) panchromatic and 15-m (45-ft) multispectral resolution with a 26-day revisit cycle, which can be reduced to 3 days with off-nadir pointing. Launched in 2023, THEOS-2 includes two satellites – THEOS-2A [a very high-resolution satellite with 0.5-m (1.5-ft) panchromatic and 2-m (6-ft) multispectral imagery] and THEOS-2B [a high-resolution satellite with 4-m (12-ft) multispectral resolution] – with a five-day revisit cycle. GISTDA also develops geospatial applications for drought assessment, flood prediction, and carbon credit calculations to support government decision-making and climate initiatives. GISTDA partners with international collaborators on regional projects, such as the Lancang-Mekong Cooperation Special Fund Project.
      Eric Vermote [NASA’s Goddard Space Flight Center] presented a keynote that focused on atmospheric correction of land remote sensing data and related algorithm updates. He highlighted the necessity of correcting surface imaging for atmospheric effects, such as molecular scattering, aerosol scattering, and gaseous absorption, which can significantly distort the satellite spectral signals and lead to potential errors in applications, such as land cover mapping, vegetation monitoring, and climate change studies.
      Vermote explained that the surface reflectance algorithm uses precise vector radiative transfer modeling to improve accuracy by incorporating atmospheric parameter inversion. It also adjusts for various atmospheric conditions and aerosol types – enhancing corrections across regions and seasons. He explained that SkyCam – a network of ground-based cameras – provides real-time assessments of cloud cover that can be used to validate cloud masks, while the Cloud and Aerosol Measurement System (CAMSIS) offers additional ground validation by measuring atmospheric conditions. He said that together, SkyCam and CAMSIS improve satellite-derived cloud masks, supporting more accurate climate models and environmental monitoring. Vermote’s work highlights the ongoing advancement of atmospheric correction methods in remote sensing.
      Other presentations in this session included one in which the speaker described how Yangon, the capital city in Myanmar, is undergoing rapid urbanization and industrial growth. From 1990–2020, the urban area expanded by over 225% – largely at the expense of agricultural and green lands. Twenty-nine industrial zones cover about 10.92% of the city, which have attracted significant foreign direct investment, particularly in labor-intensive sectors. This growth has led to challenges with land confiscations, inadequate infrastructure, and environmental issues (e.g., air pollution). Additionally, rural migration for employment has resulted in informal settlements, emphasizing the need for comprehensive urban planning that balances economic development with social equity and sustainability.
      Another presentation highlighted varying LUCC trends across Vietnam. In the Northern and Central Coastal Uplands, for example, swidden systems are shifting toward permanent tree crops, such as rubber and coffee. Meanwhile, the Red River Delta is seeing urban densification and consolidation of farmland – transitioning from rice to mixed farming with increased fruit and flower production. Similarly, the Central Coastal Lowlands and Southeastern regions are experiencing urban growth and a shift from coastal agriculture – in this case, to shrimp farming – leading to mangrove loss. The Central Highlands is moving from swidden to tree crops, particularly fruit trees, while the Mekong River Delta is increasing rice cropping and aquaculture. These changes contribute to urbanization, altered farming practices, and biodiversity loss. Advanced algorithms (e.g., the Time-Feature Convolutional Neural Network model) are being used to effectively map these varied LUCC changes in Vietnam.
      Another presenter explained how 10-m (33-ft) resolution spatially gridded population datasets are essential to address LUCC in environmental and socio-demographic research. There was also a demonstration of PopGrid, which is a collaborative initiative that provides access to various global-gridded population databases, which are valuable for regional LUCC studies and can support informed decision-making and policy development.
      DAY TWO
      The second day’s presentations centered around urban LUCC (Session IV) as well as interconnections between agriculture and water resources. (Session V).
      Session IV: Urban Land Cover/Land Use Change
      Gay Perez [Philippines Remote Sensing Agency (PhilSA)] presented a keynote focused on PhilSA’s mission to advance Philippines as a space-capable country by developing indigenous satellite and launch technologies. He explained that PhilSA provides satellite data in various categories, including sovereign, commercial, open-access, and disaster-activated. He noted that the ground infrastructure – which includes three stations and a new facility in Quezon – supports efficient data processing. For example, Perez stated that in 2023, PhilSA produced over 10,000 maps for disaster relief, agricultural assessments, and conservation planning.
      Perez reviewed PhilSA’s Diwata-2 mission, which launched in 2018 and operates in a Sun-synchronous orbit around 620 km (385 mi) above Earth. With a 10-day revisit capability, it features a high-precision telescope [4.7 m (15ft) resolution], a multispectral imager with four bands, an enhanced resolution camera, and a wide-field camera. Since launch, Diwata-2 has captured over 100,000 global images, covering 95% of the Philippines. Looking to the near future, Perez reported that PhilSA’s launch of the Multispectral Unit for Land Assessment (MULA) satellite is planned for 2025. He explained that MULA will capture images with a 5-m (~16-ft) resolution and 10–20-day revisit time, featuring 10 spectral bands for vegetation, water, and urban analysis.
      Perez also described the Drought and Crop Assessment and Forecasting project, which addresses drought risks and mapping ground motion in areas, e.g., Baguio City and Pangasinan. Through partnerships in the Pan-Asia Partnership for Geospatial Air Pollution Information (PAPGAPI) and the Pandora Asia Network, PhilSA monitors air quality across key locations, tracking urban pollution and cross-border particulate transport. PhilSA continues to strengthen Southeast Asian partnerships to drive sustainable development in the region.
      Jiquan Chen [Michigan State University] presented the second keynote address, which focused on the Urban Rural Continuum (URC). Chen emphasized the importance of synthesizing studies that explore factors such as population dynamics, living standards, and economic development in the URC. Key considerations include differentiating between two- and three-dimensional infrastructures and understanding constraints from historical contexts. Chen highlighted critical variables from his analysis including net primary productivity, household income, and essential infrastructure elements, such as transportation and healthcare systems. He advocated for integrated models that combine mechanistic and empirical approaches to grasp the dynamics of URC changes, stressing their implications for urban planning, environmental sustainability, and social equity. He concluded with a call for collaboration to enhance these models and tackle challenges arising from the changing urban–rural landscape.
      Tep Makathy [Cambodian Institute For Urban Studies] discussed urbanization in Phnom Penh, Cambodia. He explained that significant LUCC and infrastructure developments have been fueled by direct foreign investment; however, this development has resulted in environmental degradation, urban flooding, and infrastructure strain. Tackling pollution, congestion, preservation of green spaces, and preserving the historical heritage of the city will require sustainable urban planning efforts.
      Nguyen Thi Thuy Hang [Vietnam Japan University, Vietnam National University, Hanoi] explained how flooding poses a significant annual threat to infrastructure and livelihoods in Can Tho, Vietnam. Therefore, it is essential to incorporate climate change considerations into land-use planning by enhancing the accuracy of vegetation layer classifications. Doing so will improve the representation of land-cover dynamics in models that decision-makers use when planning urban development. In addition, Hang reported that a more comprehensive survey of dyke systems will improve flood protection and identify areas needing reinforcement or redesign. These studies could also explore salinity intrusion in coastal agricultural areas that could impact crop yields and endanger food security.
      In this session, two presenters highlighted how SAR data, which uses high backscatter to enhance the radar signal, is being used to assist with mapping urban areas in their respective countries. The phase stability and orientation of building structures across SAR images aid in consistent monitoring and backscatter, producing distinct image textures specific to urban settings. Researchers can use this heterogeneity and texture to map urban footprints, enabling automated discrimination between urban and non-urban areas. The first presenters showed how Interferometric Synthetic Aperture Radar techniques, such as Small Baseline Subset (SBAS) and Persistent Scatterer (PS) have been highly effective for mapping and monitoring land subsidence in coastal and urban areas in Vietnam. This approach has been applied to areas along the Saigon River as well as in Ho Chi Minh, Vietnam. The second presenter described an approach (using SAR data with multitemporal coherence and the K-means classification method) that has been used effectively to study urban growth in the Denpasar Greater Area of Indonesia between 2016 and 2022. The technique identified the conversion of 4376 km2 (1690 mi2) of rural to built-up areas, averaging 72.9 hectares (0.3 mi2) per year. Urban sprawl was predominantly observed in the North Kuta District, where the shift from agricultural to built-up land use has been accompanied by severe traffic congestion and other environmental issues.
      Another presenter showed how data from the QuikSCAT instrument, which flew on the Quick Scatterometer satellite, and from the Sentinel-1 C-band SAR can be combined to measure and analyze urban built-up volume, specifically focusing on the vertical growth of buildings across various cities. By integrating these datasets, researchers can assess urban expansion, monitor the development of high-rise buildings, and evaluate the impact of urbanization on infrastructure and land use. This information is essential for urban planning, helping city planners and policymakers make informed decisions to accommodate growing populations and enhance sustainable urban development.
      Session V – LUCC, Agriculture, and Water Resources
      Chris Justice presented the keynote for this session, in which he addressed the GEOGLAM initiative and the NASA Harvest program. GEOGLAM, initiated by the G20 Agriculture Ministers in 2011, focuses on agriculture and food security to increase market transparency and improve food security. These efforts leverage satellite-based Earth observations to produce and disseminate timely, relevant, and actionable information about agricultural conditions at national, regional, and global scales to support agricultural markets and provide early warnings for proactive responses to emerging food emergencies. NASA Harvest uses satellite Earth observations to benefit global food security, sustainability, and agriculture for disaster response, climate risk assessments, and policy support. Justice also emphasized the use of open science and open data principles, promoting the integration of Earth observation data into national and international agricultural monitoring systems. He also discussed the development and application of essential agricultural variables, in situ data requirements, and the need for comprehensive and accurate satellite data products.
      During this session, another presentation focused on how VNSC is engaged in several agricultural projects, including mapping rice crops, estimating yields, and assessing environmental impacts. VNSC has created high-accuracy rice maps for different seasons that the Vietnamese government uses to monitor and manage agricultural production. Current initiatives involve using satellite data to estimate CH4 emissions from rice paddies, biomass mapping, and monitoring rice straw burning. For example, in the Mekong Delta, numerous environmental factors, including climate change-induced stress (e.g., sea-level rise), flooding, drought, land subsidence, and saltwater intrusion, along with human activities like dam construction, sand mining, and groundwater extraction, threaten the sustainability of rice farming and farmer livelihoods. To address these challenges, sustainable agricultural practices are essential to improving rice quality, diversify farming systems, adopt low-carbon techniques, and enhance water management.
      Presentations highlighted the importance of both optical and SAR data for LUCC studies, particularly in mapping agricultural areas. A study using Landsat time-series data demonstrated its value in monitoring agricultural LUCC in Houa Phan Province, Laos, and Son La Province, Vietnam. Land cover types were classified through spectral pattern analysis, identifying distinct classes based on Landsat reflectance values. The findings revealed significant natural forest loss alongside increases in cropland and forest plantations due to agricultural expansion. High-resolution imagery validated these results, indicating the scalability of this approach for broader regional and global land-cover monitoring. Another study showcased the effectiveness of SAR data from the Phased Array type L-band Synthetic Aperture Radar-2 (PALSAR-2) on the Japanese Advanced Land Observing Satellite-2 (ALOS-2) for mapping and monitoring agricultural land use in Suphanburi, Thailand. This data proved particularly useful for capturing seasonal variations and diverse agricultural practices. Supervised machine learning methods, such as Random Forest classifiers, combined with innovative spatial averaging techniques, achieved high accuracy in distinguishing various agricultural conditions.
      In the session, presenters also discussed the use of Sentinel-1 SAR data for mapping submerged and non-submerged paddy soils was highlighted, demonstrating its effectiveness in understanding water management issues see – Figure 4. Additionally, large-scale remote sensing data and cloud computing were shown to provide unprecedented opportunities for tracking agricultural land-use changes in greater detail. Case studies from India and China illustrated key challenges, such as groundwater depletion in irrigated agriculture across the Indo-Ganges region and the impacts on food, water, and air quality in both countries.
      Figure 4. Series of Sentinel-1 radar data images showing submerged paddy soil (blue) and non-submerged paddy soil (red) in the Mekong Delta, Vietnam. Figure credit: Hiranori Arai [International Rice Research Institute] The session also focused on Water–Energy–Food (WEF) issues related to the Mekong River Basin’s extensive network of hydroelectric dams, which present both benefits and challenges. While these dams support sectors such as irrigated agriculture and hydropower, they also disrupt vital ecosystem services, including fish habitats and biodiversity. Collaborative studies integrating satellite and ground data, hydrological models, and socio-economic frameworks highlight the need to balance these benefits with ecological and social costs. Achieving sustainable management requires cross-sectoral and cross-border cooperation, as well as the incorporation of traditional knowledge to address WEF trade-offs and governance challenges in the region.
      DAY THREE
      The third day included a session that explored the impacts of fire, GHG emissions, and pollution (Session VI) as well as a summary discussion on synthesis (Session VII).
      Session VI: Fires, Greenhouse Gas Emissions, and Pollution
      Chris Elvidge [Colorado School of Mines] presented a keynote on the capabilities and applications of the Visible Infrared Imaging Radiometer Suite (VIIRS) Nightfire [VNF] system, an advanced satellite-based tool developed by the Earth Observation Group. VIIRS Nightfire uses four near- and short-wave infrared channels, initially designed for daytime imaging, to detect and monitor infrared emissions at night. The system identifies various combustion sources, including both flaming and non-flaming activities (e.g., biomass burning, gas flaring, and industrial processes). It calculates the temperature, source area, and radiant heat of detected infrared emitters using physical laws to enable precise monitoring of combustion events and provide insight into exothermic and endothermic processes.
      Elvidge explained that VNF has been vital for near-real-time data in Southeast Asia. The system has been used to issue daily alerts for Vietnam, Thailand, and Indonesia. Recent updates in Version 4 (V4) include atmospheric corrections and testing for secondary emitters with algorithmic improvements – with a 50% success rate in identifying additional heat sources. The Earth Observation Group maintains a multiyear catalog of over 20,000 industrial infrared emitters available through the Global Infrared Emitter Explorer (GIREE) web-map service. With VIIRS sensors expected to operate until about 2040 on the Joint Polar Satellite System (JPSS) platforms, this system ensures long-term, robust monitoring and analysis of global combustion events, proving essential for tracking the environmental impacts of industrial activities and natural combustion processes on the atmosphere and ecosystems.
      Toshimasa Ohara [Center for Environmental Science, Japan—Research Director] continued with the second keynote and provided an in-depth analysis of long-term trends in anthropogenic emissions across Asia. The regional mission inventory in Asia encompasses a range of pollutants and offers detailed emissions data from 1950–2020 at high spatial and temporal resolutions. The study employs both bottom-up and top-down approaches for estimating emissions, integrating satellite observations to validate data and address uncertainties. Notably, emissions from China, India, and Japan have shown signs of stabilization or reduction, attributed to stricter emission control policies and technological advancements. Ohara also highlighted Japan’s effective air pollution measures and the importance of extensive observational data in corroborating emission trends. His presentation emphasized the need for improved methodologies in emission inventory development and validation across Asia, aiming to enhance policymaking and environmental management in rapidly industrializing regions.
      Several presenters during this session focused on innovative approaches to understand and mitigate GHG emissions and air pollution. One presenter showed how NO2 data from the TROPOspheric Monitoring Instrument (TROPOMI) on the European Sentinel-5 Precursor have been validated against ground-based observations from Pandora stations in Japan, highlighting the influence of atmospheric conditions on measurement accuracy. Another presenter described an innovative system that GISTDA used to combine satellite remote sensing data with Artificial Intelligence (AI). This system was used to monitor and analyze the concentration of fine particulate matter (PM) in the atmosphere in Thailand. (In this context fine is defined as particles with diameters ≤ 2.5 µm, or PM2.5.) These applications, which are accessible through online, cloud-based platforms and mobile applications for iOS and Android devices, allow users, including citizens, government officers, and policymakers, to access PM2.5 data in real-time through web and mobile interfaces.
      A project under the United Nations Economic and Social Commission for Asia and the Pacific in Thailand is focused on improving air quality monitoring across the Asia–Pacific region by integrating satellite and ground-based data. At the core of this effort, the Pandora Asia Network, which includes 30 ground-based instruments measuring pollutants such as NO₂ and sulfur dioxide (SO₂), is complemented by high-resolution observations from the Geostationary Environment Monitoring Spectrometer (GEMS) aboard South Korea’s GEO-KOMPSAT-2B (GK-2B) satellite. The initiative also provides training sessions to strengthen regional expertise in remote sensing technologies for air quality management and develops decision support systems for evidence-based policymaking, particularly for monitoring pollution sources and transboundary effects like volcanic eruptions. Future plans include expanding the Pandora network and enhancing data integration to support local environmental management practices.
      PM2.5 levels in Vietnam are influenced by both local emissions and long-range pollutant transport, particularly in urban areas.The Vietnam University of Engineering and Technology, in conjunction with VNSC, continues to map and monitor PM2.5 using satellites and machine learning while addressing data quality issues that stem from missing satellite data and limited ground monitoring stations – see Figure 5.
      In addition to mapping and monitoring pollutants, another presentater explained that significant research is underway to address their health impacts. In Hanoi, exposure to pollutants ( e.g., PM2.5, PM10, and NO2) has led to increased rates of respiratory diseases (e.g., pneumonia, bronchitis, and asthma) among children,  as well as elevated instances of cardiovascular diseases among adults. A substantial mortality burden is attributable to fine particulate matter – particularly in densely populated areas like Hanoi. Compliance with stricter air quality guidelines could potentially prevent thousands of premature deaths. For example, preventive measures enacted during the COVID-19 pandemic resulted in reduced pollution levels that were associated with a decrease in avoidable mortality rates. In response to these challenges, Vietnam has implemented air quality management policies, including national technical regulations and action plans aimed at controlling emissions and enhancing monitoring; however, current national standards still fall short of the more stringent guidelines recommended by the World Health Organization. Improved air quality standards and effective policy interventions are needed to mitigate the health risks associated with air pollution in Vietnam.
      Figure 5. Map of particulate matter (PM 2.5) variations observed across Vietnam, using multisatellite aerosol optical depth (AOD) data from the Moderate Resolution Imaging Spectrogradiometer (MODIS) on NASA’s Aqua and Terra platforms, and from the Visible Infrared Imaging Radiometer Suite (VIIRS) on the NASA–NOAA Suomi NPP platform, combined with ground-based AOD and meteorological data. Figure credit: Thanh Nguyen [Vietnam National University of Engineering and Technology, Vietnam] Another presenter explained how food production in Southeast Asia contributes about 40% of the region’s total GHG emissions – with rice and beef production identified as the largest contributors for plant-based and animal-based emissions, respectively. Another presentation focused on a study that examined GHG emissions from agricultural activities, which suggests that animal-based food production – particularly beef – generates substantially higher GHG emissions per kg of food produced compared to plant-based foods, such as wheat and rice. Beef has an emission intensity of about 69 kg of CO2 equivalent-per-kg, compared to 2 to 3 kg of CO2 equivalent-per-kg for plant-based foods. The study points to mitigation strategies (e.g., changing dietary patterns, improving agricultural practices) and adopting sustainable land management. Participants agreed that a comprehensive policy framework is needed to address the environmental impacts of food production and reduce GHG emissions in the agricultural sector.
      In another presentation, the speaker highlighted the fact that Southeast Asian countries need an advanced monitoring, reporting, and verification system to track GHG emissions – particularly within high-carbon reservoirs like rice paddies. To achieve this, cutting-edge technologies (e.g., satellite remote sensing, low-cost unmanned aerial vehicles, and Internet of Things devices) can be beneficial in creating sophisticated digital twin technology for sustainable rice production and GHG mitigation.
      Another presentation featured a discussion about pollution resulting from forest and peatland fires in Indonesia, which is significantly impacting air quality. Indonesia’s tropical peatlands – among the world’s largest and most diverse – face significant threats from frequent fires. Repeated burning has transformed forests into shrubs and secondary vegetation regions, with fires particularly affecting forest edges and contributing to a further retreat of intact forest areas. High-resolution data is essential to map and monitor changes in forest cover, including pollution impacts.
      Another speaker described a web-based Geographic Information Systems (GIS) application that has been developed to support carbon offsetting efforts in Laos – to address significant environmental challenges, e.g., deforestation and climate change. Advanced technologies (e.g., remote sensing, GIS, and Global Navigation Satellite Systems) are used to monitor land-use changes, carbon sequestration, and ecosystem health. By integrating various spatial datasets, the web GIS app enhances data collection precision, streamlines monitoring processes, and provides real-time information to stakeholders for informed decision-making. This initiative fosters collaboration among local communities, government agencies, and international partners, while emphasizing the importance of government support and international partnerships. Ultimately, the web GIS application represents a significant advancement in Laos’s commitment to environmental sustainability, economic growth, and the creation of a greener future.
      Session VII. Discussion Session on Synthesis
      The meeting concluded with a comprehensive discussion on synthesizing themes related to LUCC. The session focused on three themes: LUCC, agriculture, and air pollution. The session focused on trends and projections as well as the resulting impacts in the coming years. It also highlighted research related to these topics to inform more sustainable land use policies. A panel of experts from different Southeast Asian countries addressed these topics. A summary of the key points shared by the panelists for each theme during the discussion is provided below.
      LUCC Discussions
      This discussion focused on the challenges of balancing economic development with environmental sustainability in Southeast Asian countries, e.g., mining in Myanmar, agriculture in Vietnam, and rising land prices in Thailand. More LUCC research is needed to inform decision-making and improve land-use planning during transitions from agriculture to industrialization while ensuring food security. The panelists also discussed urban sprawl and infrastructure development along main roads in several Southeast Asian countries, highlighting the social and environmental challenges arising from uncoordinated growth. It was noted that urban infrastructure lags behind population increases, resulting in traffic congestion, pollution, and social inequality. Cambodia, for example, has increased foreign investments, which presents similar dilemmas of economic growth accompanied by significant environmental degradation. Indonesia is another example of a Southeast Asian nation facing rapid urbanization and inadequate spatial planning, leading to flooding, groundwater depletion, and pollution. These issues further highlight the need for integrated satellite monitoring to inform land-use policies. Finally, recognizing the importance of public infrastructure in growth management, it was reported that the Thai government is already using technology to manage urban development alongside green spaces.
      Panelists agreed that LUCC research is critical for guiding policymakers toward sustainable land-use practices – emphasizing the necessity for improved communication between researchers and policymakers. While the integration of technologies (e.g., GIS and remote sensing) is beginning to influence policy decisions, room for improvement remains. In summary, the discussions stressed the importance of better planning, technology integration, and policy-informed research to reconcile economic growth with sustainability. Participants also highlighted the need to engage policymakers, non-government organizations, and the private sector in using scientific evidence for sustainable development. Capacity building in Laos, Cambodia, and Myanmar, where GIS and remote sensing technologies are still developing, is crucial. Community involvement is essential for translating research findings into actionable policies to address real-world challenges and social equity.
      Agriculture Discussions
      These discussions explored the intricate relationships between agricultural practices, economic growth, and environmental sustainability in Southeast Asia. As an example, despite national policies to manage the land transition in Vietnam, rapid conversions from forest to agricultural land and further to residential and industrial continue. While it is recognized that strict land management plans may hinder future adaptability, further regulation is needed. These rapid shifts in land use have increased land for economic development – especially in industrial and residential sectors – and contribute to environmental degradation, e.g., pollution and soil erosion. In Thailand, land is distributed among agriculture (50%), forest (30%), and urban (20%) areas. Despite a long history of agricultural practices, Vietnam faces new challenges from climate change and extreme weather.
      Thailand, meanwhile, is exploring carbon credits to incentivize sustainable farming practices – although this requires significant investment and time. The nation is well-equipped with a robust water supply system, and ongoing efforts to enhance crop yields on Vietnam’s Mekong Delta, salinity levels, and flooding intensity have increased as a result of the rise in incidents of extreme weather, prompting advancements in rice farming mechanization to be implemented that are modeled after practices that have been successfully used in the Philippines.
      Despite these advances, issues (e.g., over-application of rice seeds) remain. The dominant land cover type in Malaysia is tropical rainforest, although agriculture – particularly oil palm plantations – also plays a significant role in land use. While stable, it shares environmental concerns with Indonesia. The country is integrating solar energy initiatives, placing solar panels on former agricultural lands and recreational areas, which raises coastal environmental concerns. In Taiwan, substantial land use changes have stemmed from solar panel installations to support green energy goals but have led to increased temperatures and altered wind patterns.
      All panelists agreed that remote sensing technologies are vital to inform agricultural policy across the region. They emphasized the need to transition from academic research to actionable insights that directly inform policy. Panelists also discussed the challenge of securing funding for actionable research – underlining the importance of recognizing the transition required for research to inform operational use. Some countries (e.g., Thailand) have established operational crop monitoring systems, while others (e.g., Vietnam) primarily depend on research projects. Despite progress in Malaysia’s monitoring of oil palm plantations, a comprehensive operational monitoring system is still lacking in many areas. The participants concluded that increased efforts are needed to promote the wider adoption of remote sensing technologies for agricultural and environmental monitoring, with emphasis on developing operational systems that can be integrated into policy and decision-making processes.
      Air Pollution Discussions
      The discussion on air pollution focused on various sources in Southeast Asia, which included both local and transboundary factors. Panelists highlighted that motor vehicles, industrial activities, and power plants are major contributors to pollutants, such as PM2.5, NO2, ozone (O3), and carbon monoxide (CO). Forest fires in Indonesia – particularly from South Sumatra and Riau provinces – are significantly impacting neighboring countries, e.g., Malaysia. A study found that most PM2.5 pollution in Kuala Lumpur originates from Indonesia. During the COVID-19 pandemic, pollution levels dropped sharply due to reduced economic activity; however, data from 2018–2023 shows that PM2.5 levels have returned to pre-pandemic conditions.
      The Indonesian government is actively working to reduce deforestation and emissions, aiming for a 29% reduction by 2030. Indonesia is also participating in carbon markets and receiving international payments for emission reductions. Indonesia’s emissions also stem from energy production, industrial activities, and land-use changes, including peat fires. The Indonesian government reports anthropogenic sources – particularly from the energy sector and industrial activities, forest and peat fires, waste, and agriculture – continue to escalate. While Indonesia is addressing these issues, growing population and energy demands continue to drive pollution levels higher.
      Vietnam and Laos are facing similar challenges related to air pollution – particularly from agricultural residue burning. Both governments are working on expanding air quality monitoring, regulating waste burning, and developing policies to mitigate pollution. Vietnam has been developing provincial air quality management plans and expanding its monitoring network. Laos has seen increased awareness of pollution, accompanied by government measures aimed at restricting burning and improving waste management practices.
      The panelists agreed that collaborative efforts for regional cooperation are essential to address air pollution. This will require collaboration in research and data sharing to inform policy decisions. There is a growing interest in leveraging satellite technology and modeling approaches to enhance air quality forecasting and management. To ensure that research translates into effective policy, communication of scientific findings to policymakers is essential – particularly by clearly communicating complex research concepts in accessible formats. All panelists agreed on the importance of improving governance, transparency, and scientific communication to better translate research into policy actions, highlighting collaborations with international organizations – including NASA – to address air quality issues. While significant challenges related to air pollution persist in Southeast Asia, noteworthy efforts are underway to improve awareness, research, and collaborative governance aimed at enhancing air quality and reducing emissions.
      Conclusion
      The LCLUC–SARI Synthesis meeting fostered collaboration among researchers and provided valuable updates on recent developments in LUCC research, exchange of ideas, integration of new data products, and discussions on emerging science directions. This structured dialogue (particularly the discussions in each session) helped the attendees identify priorities and needs within the LUCC community. All panelists and meeting participants commended the SARI leadership for their proactive role in facilitating collaborations and discussions that promote capacity-building activities across the region. SARI activities have significantly contributed to enhancing the collective ability of countries in South and Southeast Asia to address pressing environmental challenges. The meeting participants emphasized the importance of maintaining and expanding these collaborative efforts, which are crucial for fostering partnerships among governments, research institutions, and local communities. They urged SARI to continue organizing workshops, training sessions, and knowledge-sharing platforms that can equip stakeholders with the necessary skills and resources to tackle environmental issues such as air pollution, deforestation, climate change, and sustainable land management.
      Krishna Vadrevu
      NASA’s Marshall Space Flight Center
      krishna.p.vadrevu@nasa.gov
      Vu Tuan
      Vietnam National Science Center, Vietnam
      vatuan@vnsc.org.vn
      Than Nguyen
      Vietnam National University Engineering and Technology, Vietnam
      thanhntn@vnu.edu.vn
      Son Nghiem
      Jet Propulsion Laboratory
      son.v.nghiem@jpl.nasa.gov
      Tsuneo Matsunaga
      National Institute of Environmental Studies, Japan
      matsunag@nies.go.jp
      Garik Gutman
      NASA Headquarters
      ggutman@nasa.gov
      Christopher Justice
      University of Maryland College Park
      cjustice@umd.edu
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      NASA Science: Being Responsive to Executive Orders
      February 18, 2025
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    • By NASA
      The 2024 Annual Highlights of Results from the International Space Station is now available. This new edition contains updated bibliometric analyses, a list of all the publications documented in fiscal year 2024, and synopses of the most recent and recognized scientific findings from investigations conducted on the space station. These investigations are sponsored by NASA and all international partners – CSA (Canadian Space Agency), ESA (European Space Agency), JAXA (Japan Aerospace Exploration Agency), and the State Space Corporation Roscosmos (Roscosmos) – for the advancement of science, technology, and education.
      Dr. Dmitry Oleynikov remotely operates a surgical robot aboard the Space Station using controls at the Virtual Incision offices in Lincoln, Nebraska. Robotic Surgery Tech Demo tests techniques for performing a simulated surgical procedure in microgravity using a miniature surgical robot that can be remotely controlled from Earth. Credits: University of Nebraska-Lincoln Between Oct. 1, 2023, and Sept. 30, 2024, more than 350 publications were reported. With approximately 40% of the research produced in collaboration between more than two countries and almost 80% of the high-impact studies published in the past seven years, station has continued to generate compelling and influential science above national and global standards since 2010.
      The results achieved from station research provide insights that advance the commercialization of space and benefit humankind.
      Some of the findings presented in this edition include:
      Improved machine learning algorithms to detect space debris (Italian Space Agency, Roscosmos, ESA) Visuospatial processing before and after spaceflight (CSA) Metabolic changes during fasting intervals in astronauts (ESA) Vapor bubble production for the improvement of thermal systems (NASA) Immobilization of particles for the development of optical materials (JAXA) Maintained function of cardiac 3D stem cells after weeks of exposure to space (NASA) The content in the Annual Highlights of Results from the International Space Station has been reviewed and approved by the International Space Station Program Science Forum, a team of scientists and administrators representing NASA and international partners that are dedicated to planning, improving, and communicating the research operated on the space station.
      [See the list of Station Research Results publications here and find the current edition of the Annual Highlights of Results here.]  
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      View the full article
    • By NASA
      Modeling properties of thunderstorm discharges

      Researchers report detailed physical properties of different types of corona discharges, including single- and multi-pulse blue discharges linked to powerful but short-lived electrical bursts near the tops of clouds. These details provide a reference for further investigation into the physical mechanisms behind these discharges and their role in the initiation of lightning, an important problem in lightning physics.

      An ESA (European Space Agency) instrument used to study thunderstorms, Atmosphere-Space Interactions Monitor (ASIM) provides insights into their role in Earth’s atmosphere and climate, including mechanisms behind the creation of lightning. Understanding how thunderstorms and lightning disturb the upper atmosphere could improve atmospheric models along with climate and weather predictions. These high-altitude discharges also affect aircraft and spacecraft safety.

      An artist’s impression of a blue jet as observed from the International Space Station.Mount Visual/University of Bergen/DTU Space Evaluating effects of climate change on oceans

      Researchers conclude that the space station’s ECOSTRESS instrument yields highly accurate sea surface temperature data. Given the instrument’s global coverage and high spatial resolution, these data have potential use in studies of biological and physical oceanography to evaluate regional and local effects of climate change.

      ECOSTRESS resolves oceanographic features not detectable in imagery from NOAA’s Visible Infrared Imaging Radiometer Suite satellite, and has open-ocean coverage, unlike Landsat. Satellites are a fundamental tool to measure sea surface temperatures, which are rising across all oceans due to atmospheric warming induced by climate change.

      The ECOSTRESS instrument, the white box in the center, is visible on the outside of the station.NASA Describing a gamma ray burst

      Researchers report detailed observations and analysis of emissions from an exceptionally bright gamma ray burst (GRB), 210619B, detected by the station’s ASIM and other satellite and ground-based instruments. These observations could be useful in determining various properties of GRBs and how they change during different phases.

      Believed to be generated by the collapse of massive stars, GRBs are the brightest, most explosive transient electromagnetic events in the universe. ASIM can observe thunderstorm discharges difficult to observe from the ground. It has a mode where a detected event triggers observation and onboard storage of data.

      A view of ASIM mounted on the outside of the space station. NASAView the full article
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