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Summary of the Ninth DSCOVR EPIC and NISTAR Science Team Meeting


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Summary of the Ninth DSCOVR EPIC and NISTAR Science Team Meeting

Introduction

The ninth Deep Space Climate Observatory (DSCOVR) Earth Polychromatic Camera (EPIC) and National Institute of Standards and Technology (NIST) Advanced Radiometer [NISTAR] Science Team Meeting (STM) was held virtually October 16–17, 2023. Over 35 scientists attended, most of whom were from NASA’s Goddard Space Flight Center (GSFC), with several participating from other NASA field centers, U.S. universities, and U.S. Department of Energy laboratories. One international participant joined the meeting from Estonia. A full overview of DSCOVR’s Earth-observing instruments was printed in a previous article in The Earth Observer and will not be repeated here. This article provides the highlights of the 2023 meeting. The meeting agenda and full presentations can be downloaded from GSFC’s Aura Validation Data Center.

Opening Presentations

The opening session consisted of a series of presentations from DSCOVR mission leaders and representatives from GSFC and NASA Headquarters (HQ), who gave updates on the mission and the two Earth-viewing science instruments on board. Alexander Marshak [GSFC—DSCOVR Deputy Project Scientist] opened the meeting. He discussed the agenda for the meeting and mentioned that both Earth science instruments on DSCOVR are functioning normally – see Figure 1. At this time, more than 115 papers related to DSCOVR are listed on the EPIC website. Marshak emphasized the importance of making the Earth Science community more aware of the availability of the various EPIC and NISTAR science data products.

DSCVR figure 1
Figure 1. Sun-Earth-Vehicle (SEV) angle (red curve) and the distance between Earth and the DSCOVR satellite (blue curve) versus time starting from the DSCOVR launch on February 15, 2015 to April 1, 2024. These two measurements are used to track the location and orientation, respectively, of DSCOVR. The spacecraft changes its location by about 200,000 km (~124,274 mi) over about a 3-month period, and its SEV gets close to zero (which would correspond to perfect backscattering). The gap around the year 2020 was when DSCOVR was in Safe Mode for an extended period.
Figure credit: Adam Szabo (Original figure by Alexander Marshak, with data provided by Joe Park/NOAA)

Adam Szabo [GSFC—DSCOVR Project Scientist] welcomed the STM participants and briefly reported that the spacecraft, located at “L1” – the first of five Lagrange points in the Sun-Earth system – was still in “good health.” The EPIC and NISTAR instruments on DSCOVR continue to return their full science observations. Szabo gave an update on the 2023 Earth Science Senior Review, which DSCOVR successfully passed with overall science scores of ‘Excellent/Very Good.’ The Senior Review Panel unanimously supported the continuation of DSCOVR for the 2024–2026 period.

Thomas Neumann [GSFC, Earth Sciences Division (ESD)—Deputy Director] welcomed meeting participants on behalf of the ESD. Neumann noted the impressive engineering that has led to 8.5 years of operations and counting. He also commended the team on the continued production of important science results from these instruments – with nearly 110 papers in the peer-reviewed literature.

Following Neumann’s remarks, Steve Platnick [GSFC, Earth Sciences Division—Deputy Director for Atmospheres] welcomed the members of the DSCOVR ST as well as users of EPIC and NISTAR observations. He thanked NASA HQ for its continued strong interest in the mission. Platnick also expressed his appreciation for the mission team members who have worked hard to maintain operation of the DSCOVR satellite and instruments during this challenging time.

Richard Eckman [NASA HQ, Earth Science Division—DSCOVR EPIC/NISTAR Program Scientist] noted that a new call for proposals will be in ROSES-2025 and looks forward to learning about recent accomplishments by ST members, which will be essential in assessing the mission’s performance.

Jack Kaye [NASA HQ, Earth Science Division—Associate Director for Research] discussed the NASA research program that studies the Earth, using satellites, aircraft, surface-based measurements, and computer models. The two Earth science instruments on DSCOVR (EPIC and NISTAR) play an important role in the program. He highlighted the uniqueness of the DSCOVR observations from the Sun–Earth “L1” point providing context for other missions and the ability to discern diurnal variations.

Updates on DSCOVR Operations

The DSCOVR mission components continue to function nominally, with progress on several fronts, including data acquisition, processing, archiving, and release of new versions of several data products. The number of people using the content continues to increase, with a new Science Outreach Team having been put in place to aid users in several aspects of data discovery, access, and user friendliness.

Hazem Mahmoud [NASA’s Langley Research Center (LaRC)] discussed the new tools in the Atmospheric Science Data Center (ASDC). He reported on DSCOVR metrics since 2015 and mentioned the significant increase in using ozone (O3) products. He also announced that ASDC is moving to the Amazon Web Services (AWS) cloud.

Karin Blank [GSFC] covered the EPIC geolocation algorithm, including the general algorithm framework. She highlighted additional problems that needed to be resolved and detailed the various stages to refine the algorithm, emphasizing the enhancements made to improve geolocation accuracy.

Marshall Sutton [GSFC] reported on the DSCOVR Science Operations Center (DSOC) and Level-2 (L2) processing. DSOC is operating nominally. EPIC L1A, L1B, and NISTAR data files are produced daily. EPIC L1 products are processed into L2 science products using the computing power of the NASA Center for Climate Simulations (NCCS). Products include daily data images, including a cloud fraction map, aerosol map, and the anticipated aerosol height image. In addition, Sutton reported that the DSCOVR spacecraft has enough fuel to remain in operation until 2033.

EPIC Calibration

Alexander Cede [SciGlob] and Ragi Rajagopalan [LiftBlick OG] reported on the latest EPIC calibration version (V23) that includes the new flat field corrections based on the lunar observations from 2023 and an update to the dark count model. The EPIC instrument remains healthy and shows no change in parameters, e.g., read noise, enhanced or saturated pixels, or hot or warm pixels. The current operational dark count model still describes the dark count in a satisfactory way.

Liang-Kang Huang [Science Systems and Applications, Inc. (SSAI)] reported on EPIC’s July 2023 lunar measurements, which filled in the area near diagonal lines of the charged coupled device (CCD) not covered by 2021 and 2022 lunar data. With six short wavelength channels ranging from 317 to 551 nm, the two sets of lunar data are consistent with each other. For the macroscopic flat field corrections, he recommended the six fitted sensitivity change functions of radius and polar angle. 

Igor Geogdzhaev [NASA’s Goddard Institute for Space Studies (GISS)/Columbia University] reported how continuous EPIC observations provide stable visible and near infrared (NIR) channels compared to the contemporaneous data from Visible Infrared Imaging Radiometer Suite (VIIRS) on NASA’s Suomi National Polar-orbiting Partnership (Suomi NPP) and the NASA–National Oceanic and Atmospheric Administration (NOAA) Joint Polar Satellite System (JPSS) missions. (To date, two JPSS missions have launched, JPSS-1, which is now known as NOAA-20, and JPSS-2, which is now known as NOAA-21.) Analysis of near simultaneous data from EPIC and from the Advanced Baseline Imager (ABI) on the Geostationary Operational Environmental Satellite–R (GOES R) platforms showed a high correlation coefficient, good agreement between dark and bright pixels, and small regression zero intercepts. EPIC moon views were used to derive oxygen (O2) channel reflectance by interpolation of the calibrated non-absorbing channels.

Conor Haney [LaRC] reported that the EPIC sensor was intercalibrated against measurements from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra and Aqua platforms as well as from VIIRS on Suomi NPP and NOAA-20, using ray-matched pair radiances, and was found to be radiometrically stable when tested against two invariant calibration targets: over deep convective clouds over the tropical Pacific (dark target) and over the Libya-4 site located in the Libyan desert in Africa (bright target). The ray-matched and Earth target EPIC gain trends were found to be consistent within 1.1%, and the EPIC sensor degradation was found to be less than 1% over the seven-year record. Preliminary results intercalibrating EPIC with the Advanced Himawari Imager (AHI) on the Japan Aerospace Exploration Agency’s (JAXA) “Himawari–8” Geostationary Meteorological Satellite were also promising when both subsatellite positions were close—i.e., during equinox.

NISTAR Status and Science with Its Observations

The NISTAR instrument remains fully functional and continues its uninterrupted data record. The presentations here include more details on specific topics related to NISTAR as well as on efforts to combine information from both EPIC and NISTAR.

Steven Lorentz [L-1 Standards and Technology, Inc.] reported that NISTAR has been measuring the irradiance from the Sun-lit Earth in three bands for more than eight years. The bands measure the outgo­ing reflected solar and total radiation from Earth at a limited range of solar angles. These measurements assist researchers in answering questions addressing Earth radiation imbalance and predicting future climate change. NISTAR continues to operate nominally, and the team is monitoring any in-orbit degradation. Lorentz explained the evolution of the NISTAR view angle over time. He also provided NISTAR shortwave (SW) and photodiode (PD) intercomparison. NISTAR has proven itself to be an extremely stable instrument – although measurements of the offsets have measurement errors. A relative comparison with the scaled-PD channel implies long-term agreement below a percent with a constant background.

Clark Weaver [University of Maryland, College Park (UMD)] discussed updates to a new reflected- SW energy estimate from EPIC. This new product uses generic Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) aircraft observations over homogeneous scenes to spectrally interpolate between the coarse EPIC channels. This approach assumes the spectra from an EPIC pixel is a weighted combination of a solid cloud scene and the underlying (cloud-free) surface. Weaver and his team used a vector discrete ordinate radiative transfer model with a full linearization facility, called VLIDORT, to account for the different viewing/illumination geometry of the sensors. Each pixel residual between EPIC observations at six different wavelengths (between 340 and 780 nm) and the composite high-resolution spectrum from AVIRIS has been reduced by about 50%, since the last report. While the total reflected energy for a single EPIC image can be about 15 W/m2 different than the NISTAR measurement, by 2017 the offset bias was, on average, about 1 W/m2

Andrew Lacis [GISS] said that DSCOVR measurements of Earth’s reflected solar radiation from the “L1” position offer a unique perspective for the continuous monitoring of Earth’s sunlit hemisphere. Six years of EPIC data show the seasonal and diurnal variability of Earth’s planetary albedo – but with no discernible trend. Planetary scale variability, driven by changing patterns in cloud distribution, is seen to occur at all longitudes over a broad range of time scales. The planetary albedo variability is strongly correlated at neighboring longitudes but shows strongly anticorrelated behavior at diametrically distant longitudes.

Update on EPIC Products and Science Results

EPIC has a suite of data products available. The following subsections summarize content during the DSCOVR STM related to these products. They provide updates on several of the data products and on related algorithm improvements. 

Total Column Ozone

Natalya Kramarova [GSFC] reported on the status of the EPIC total O3 using the V3 algorithm. The absolute calibrations are updated every year using collocated observations from the Ozone Mapping and Profiling Suite (OMPS) on Suomi NPP. EPIC total O3 measurements are routinely compared with independent satellite and ground-based measurements. Retrieved EPIC O3 columns agree within ±5–7 Dobson Units (DU, or 1.5–2.5%) with independent observations, including those from satellites [e.g., Suomi NPP/OMPS, NASA’s Aura/Ozone Monitoring Instrument (OMI), European Union’s (EU) Copernicus Sentinel-5 Precursor/TROPOspheric Monitoring Instrument (TROPOMI)], sondes, and ground-based Brewer and Dobson spectrophotometers. The EPIC O3 record is stable and shows no substantial drifts with respect to OMPS. In the future, the EPIC O3 team plans to compare EPIC time resolved O3 measurements with observations from NASA’s Tropospheric Emissions Monitoring of Pollution (TEMPO) and the South Korean Geostationary Environment Monitoring Spectrometer (GEMS) – both in geostationary orbit. (Along with the EU’s Copernicus Sentinel-4 mission, expected to launch in 2024, these three missions form a global geostationary constellation for monitoring air quality on spatial and temporal scales that will help scientists better understand the causes, movement, and effects of air pollution across some of the world’s most populated areas.) 

Jerrald Ziemke [Morgan State University] explained that tropospheric column O3 is measured over the disk of Earth every 1–2 hours. These measurements are derived by combining EPIC observations with Modern-Era Retrospective Analysis for Research and Applications (MERRA2) assimilated O3 and tropopause fields. These hourly maps are available to the public from the Langley ASDC and extend over eight years from June 2015 to present. The EPIC tropospheric O3 is now indicating post-COVID anomalous decreases of ~3 DU in the Northern Hemisphere for three consecutive years (2020–2022). Similar decreases are present in other satellite tropospheric O3 products as well as OMI tropospheric nitrogen dioxide (NO2), a tropospheric O3 precursor.

Algorithm Improvement for Ozone and Sulfur Dioxide Products

Kai Yang [UMD] presented the algorithm for retrieving tropospheric O3 from EPIC by estimating the stratosphere–troposphere separation of retrieved O3 profiles. This approach contrasts with the traditional residual method, which relies on the stratospheric O3 fields from independent sources. Validated against the near-coincident O3 sonde measurements, EPIC data biased low by a few DU (up to 5 DU), consistent with EPIC’s reduced sensitivity to O3 in the troposphere. Comparisons with seasonal means of TROPOMI tropospheric O3 show consistent spatial and temporal distributions, with lows and highs from atmospheric motion, pollution, lightning, and biomass burning. Yang also showed EPIC measurements of sulfur dioxide (SO2) from recent volcanic eruptions, including Mauna Loa and Kilauea (Hawaii, U.S., 2022–2023), Sheveluch (Kamchatka, Russia, 2023), Etna (Italy, 2023), Fuego (Guatemala, 2023), Popocatépetl (Mexico, 2023), and Pavlof and Shishaldin (Aleutian Islands, U.S., 2023). Yang reported the maximum SO2 mass loadings detected by EPIC are 430 kt from the 2022 Mauna Loa and Kilauea eruptions and 351 kt from the 2023 Sheveluch eruption.

Simon Carn [University of Michigan] showed EPIC observations of major volcanic eruptions in 2022–2023 using the EPIC L2 volcanic SO2 and UV Aerosol Index (UVAI) products to track SO2 and ash emissions. EPIC SO2 and UVAI measurements during the 2023 Sheveluch eruption show the coincident transport of volcanic SO2, ash, and Asian dust across the North Pacific. The high-cadence EPIC UVAI can be used to track the fallout of volcanic ash from eruption clouds, with implications for volcanic hazards. EPIC SO2 measurements during the November 2022 eruption of Mauna Loa volcano are being analyzed in collaboration with the U.S. Geological Survey, who monitored SO2 emissions using ground-based instruments during the eruption. Carn finished by mentioning that EPIC volcanic SO2 algorithm developments are underway including the simultaneous retrieval of volcanic SO2 and ash.

Aerosols

Myungje Choi [UMD, Baltimore County (UMBC)] presented an update on the EPIC V3 Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithm to optimize smoke aerosol models and the inversion process. The retrieved smoke/dust properties showed an improved agreement with long-term, ground-based Aerosol Robotic Network (AERONET) measurements of solar spectral absorption (SSA) and with aerosol layer height (ALH) measurements from the Cloud–Aerosol Lidar with Orthogonal Projection (CALIOP) on the Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) mission. (Update: As of the publication of this summary, both CALIPSO and CloudSat have ended operations.) Choi reported that between 60–90% of EPIC SSA retrievals are within ±0.03 of AERONET SSA measurements, and between 56–88% of EPIC ALH retrievals are within ±1km of CALIOP ALH retrievals. He explained that the improved algorithm effectively captures distinct smoke characteristics, e.g., the higher brown carbon (BrC) fraction from Canadian wildfires in 2023 and the higher black carbon (BC) fraction from agricultural fires over Mexico in June 2023.

Sujung Go [UMBC] presented a global climatology analysis of major absorbing aerosol species, represented by BC and BrC in biomass burning smoke as well as hematite and goethite in mineral dust. The analysis is based on the V3 MAIAC EPIC dataset. Observed regional differences in BC vs. BrC concentrations have strong associations with known distributions of fuels and types of biomass burning (e.g., forest wildfire vs. agricultural burning) and with ALH retrievals linking injection heights with fire radiative power. Regional distributions of the mineral dust components have strong seasonality and agree well with known dust properties from published ground soil samples.

Omar Torres [GSFC] reported on the upgrades of the EPIC near-UV aerosol (EPICAERUV) algorithm. The EPICAERUV algorithm’s diurnal cycle of aerosol optical depth compared to the time and space collocated AERONET observations at multiple sites around the world. The analysis shows remarkably close agreement between the two datasets. In addition, Torres presented the first results of an improved UV-VIS inversion algorithm that simultaneously retrieves aerosol layer height, optical depth, and single scattering albedo.

Hiren Jethva [Morgan State University] discussed the unique product of absorbing aerosols above clouds (AAC) retrieved from EPIC near-UV observations between 340 and 388 nm. The validation analysis of the retrieved aerosol optical depth over clouds against airborne direct measurements from the NASA ObseRvations of Aerosols above CLouds and their intEractionS (ORACLES) campaign revealed a robust agreement. EPIC’s unique capability of providing near-hourly observations offered an insight into the diurnal variations of regional cloud fraction and AAC over “hotspot” regions. A new and simple method of estimating direct radiative effects of absorbing aerosols above clouds provided a multiyear timeseries dataset, which is consistent with similar estimations from Aura–OMI.

Jun Wang [University of Iowa] reported on the development and status of V1 of the L2 EPIC aerosol optical centroid height (AOCH) product – which is now publicly available through ASDC – and on improvements to the AOCH algorithm – which focus on the treatment of surface reflectance and aerosols models. He presented applications of this data product for both climate studies of Sahara dust layer height and air quality studies of surface particulate matter with diameter of 2.5 µm or less (PM2.5). In addition, Wang showed the comparisons of EPIC AOCH data product with those retrieved from TROPOMI and GEMS and discussed ongoing progress to reduce the AOCH data uncertainty that is estimated to be 0.5 km (0.3 mi) over the ocean and 0.8 km (0.5 mi) over land.

Clouds

Yuekui Yang [GSFC] explained the physical meaning of EPIC cloud effective pressure (CEP) in an “apples-to-apples” comparison with CEP measurements from the Global Ozone Monitoring Experiment 2 (GOME-2) on the European Operational Meteorology (MetOp) satellites. The results showed that the two products agreed well.

Yaping Zhou [UMBC] showed how current EPIC O2 A-band and B-band use Moon calibrations due to lack of in-flight calibration and other comparable in-space instruments for absolute calibration. This approach is ineffective at detecting small changes in instrument response function (IRF). This study examined the O2 band’s calibration and stability using a unique South Pole location and Radiative Transfer Model (RTM) simulations with in situ soundings and surface spectral albedo and bidirectional reflectance distribution function (BRDF) measurements as input. The results indicate EPIC simulations are within 1% of observations for non-absorption bands, but large discrepancies exist for the O2 A-band (15.63%) and O2 B-band (5.76%). Sensitivity studies show the large discrepancies are unlikely caused by uncertainties in various input, but a small shift (-0.2–0.3 nm) of IRF could account for the model observation discrepancy. On the other hand, observed multiyear trends in O2 band ratios in the South Pole can be explained with orbital shift – which means the instrument is stable.

Alfonso Delgado Bonal [UMBC] used the EPIC L2 cloud data to characterize the diurnal cycles of cloud optical thickness. To fully exploit the uniqueness of DSCOVR data, all clouds were separated in three groups depending on their optical thickness: thin (0–3), medium (3–10), and thick (3–25). Bonal explained that there is a predictable pattern for different latitudinal zones that reaches a maximum around noon local time – see Figure 2. It was also shown that that the median is a better measure of central tendency when describing cloud optical thickness.

DSCVR Figure 2
Figure 2. Daytime variability of the median liquid cloud optical thickness over the ocean for different seasons of the year derived using EPIC L2 data. The various colored curves represent data collected in different seasons of the year. The black curve represents the annual average – which is most useful for calculations of cloud optical thickness.
Figure credit: Alfonso Delgado Bonal

Elizabeth Berry [Atmospheric and Environmental Research (AER)] reported on how coincident observations from EPIC and the Cloud Profiling Radar (CPR) on CloudSat have been used to train a machine learning model to predict cloud vertical structure. A XGBoost decision tree model used input (e.g., EPIC L1B reflectance, L2 Cloud products, and background meteorology) to predict a binary cloud mask on 25 vertical levels. Berry discussed model performance, feature importance, and future improvements.

Ocean

Robert Frouin [Scripps Institution of Oceanography, University of California] discussed ocean surface radiation products from EPIC data. He reported that surface radiation products were developed to address science questions pertaining to biogeochemical cycling of carbon, nutrients, and oxygen as well as mixed-layer dynamics and circulation. These products include daily averaged downward planar and scalar irradiance and average cosine for total light just below the surface in the EPIC spectral bands centered on 317.5, 325, 340, 388, 443, 551, and 680 nm and integrated values over the photosynthetically active radiation (PAR) and UV-A spectral ranges. The PAR-integrated quantities were evaluated against in situ data collected at sites in the North Atlantic Ocean and Mediterranean Sea. Frouin and his colleagues have also developed, tested, and evaluated an autonomous system for collecting and transmitting continuously spectral UV and visible downward fluxes. 

Vegetation

Yuri Knyazikhin [Boston University] reported on the status of the Vegetation Earth System Data Record (VESDR) and discussed science with vegetation parameters. A new version of the VESDR software was delivered to NCCS and implemented for operational generation of the VESDR product. The new version passed tests of physics (e.g., various relationships between vegetation indices and vegetation parameters derived from the VESDR) and follow regularities reported in literature. Analysis of hotspot signatures derived from EPIC and from the Multiangle Imaging Spectroradiometer (MISR) on Terra over forests in southeastern Democratic Republic of the Congo reaffirms that long-term precipitation decline has had minimal impact on leaf area and leaf optical properties.

Jan Pisek [University of Tartu/Tartu Observatory, Estonia] reported on the verification of the previously modeled link between the directional area scattering factor (DASF) from the EPIC VESDR product and foliage clumping with empirical data. The results suggest that DASF can be accurately derived from satellite observations and provide new evidence that the photon recollision probability theory concepts can be successfully applied even at a fairly coarse spatial resolution.

Sun Glint

Tamás Várnai [UMBC] discussed the EPIC Glint Product as well as impacts of sun glint off ice clouds on other EPIC data products – see Figure 3. The cloud glints come mostly from horizontally oriented ice crystals and have strong impact in EPIC cloud retrievals. Glints increase retrieved cloud fraction, the retrieved cloud optical depth, and cloud height. Várnai also reported that the EPIC glint product is now available at the ASDC. It is expected that glints yield additional new insights about the microphysical and radiative properties of ice clouds.

DSCVR figure 3
Figure 3. EPIC image taken over Mexico on July 4, 2018. The red, white and blue spot over central Mexico is the result of Sun glint reflecting off high clouds containing ice crystals. EPIC is particularly well suited for studies of ice clouds that cause Sun glint, because unlike most other instruments, it uses a filter wheel to take images at multiple wavelengths, which means the image for each wavelength is obtained at a slightly different time. For example, it takes four minutes to cycle from red to blue. During that time, Earth moves by ~100 km (~62 mi) meaning each image will capture a slightly different scene. Brightness contrasts between images can be used to identify glint signals.
Image credit: Tamas Vanai

Alexander Kostinski [Michigan Technology University] reported on long-term changes and semi-permanent features, e.g., ocean glitter. They introduced pixel-pinned temporally and conditionally averaged reflectance images, uniquely suited to the EPIC observational circumstances. The preliminary resulting images (maps), averaged over months and conditioned on cover type (land, ocean, or clouds), show seasonal dependence at a glance (e.g., by an apparent extent of polar caps).

More EPIC Science Results

Guoyong Wen [Morgan State University] discussed spectral properties of the EPIC observations near backscattering, including four cases when the scattering angle reaches about 178° (only 2° from perfect backscattering). The enhancement addresses changes in scattering angle observed in 2020. (Scattering angle is a function of wavelength, because according to Mie scattering theory, the cloud scattering phase function in the glory region is wavelength dependent.) Radiative transfer calculations showed that the change in scattering angles has the largest impact on reflectance in the red and NIR channels at 680 nm and 780 nm and the smallest influence on reflectance in the UV channel at 388 nm – consistent with EPIC observations. The change of global average cloud amount also plays an important role in the reflectance enhancement.

Nick Gorkavyi [SSAI] talked about future plans to deploy a wide-angle camera and a multislit spectrometer on the Moon’s surface for whole-Earth observations to complement EPIC observations. Gorkavyi explained that the apparent vibrational movement of Earth in the Moon’s sky complicates observations of Earth. This causes the center of Earth to move in the Moon’s sky in a rectangle, measuring 13.4° × 15.8° with a period of 6 years. 

Jay Herman [UMBC] reported on EPIC O3 and trends from combining Nimbus 7/Solar Backscatter Ultraviolet (SBUV), the SBUV-2 series, and OMPS–Nadir Mapper (NM) data. (OMPS is made up of three instruments: a Nadir Mapper (NM), Nadir Profiler, and Limb Profiler. OMPS NM is a total ozone sensor). Herman compared EPIC O3 data to OMPS NM data, which showed good agreement (especially summer values) for moderate solar zenith angle (SZA). Comparison with long-term O3 time series (1978–2021) revealed that there were trends and latitude dependent O3 turn-around dates (1994–1998). Herman emphasized that global O3 models do not show this effect but rather have only a single turn-around date around 2000.

Alexander Radkevich [LaRC] presented a poster that showed a comparative analysis of air quality monitoring by orbital and suborbital NASA missions using the DSCOVR EPIC O3 product as well as Pandora total O3 column retrievals. Comparison of the June 2023 total column O3 from EPIC data to the same periods in previous years revealed a significant – around 50 DU – increase of total O3 column in the areas impacted by the plume from 2023 Canadian wildfires.

Conclusion

At the end of the meeting Alexander Marshak, Jay Herman, and Adam Szabo discussed how to make the EPIC and NISTAR instruments more visible in the community. The EPIC website now allows visitors to observe daily fluctuations of aerosol index, cloud fraction, and the ocean surface – as observed from the “L1” point,  nearly one million miles away from Earth! More daily products, (e.g., cloud and aerosol height, total leaf area index, and sunlit leaf area index) will be added soon.

The 2023 DSCOVR EPIC and NISTAR Science Team Meeting provided an opportunity to learn the status of DSCOVR’s Earth-observing instruments, EPIC and NISTAR, the status of recently released L2 data products, and the science results being achieved from the “L1” point. As more people use DSCOVR data worldwide, the ST hopes to hear from users and team members at its next meeting. The latest updates from the mission are found on the EPIC website. (UPDATE: The next DSCOVR EPIC and NISTAR STM will be held on October 16–18, 2024. Check the website for more details as the date approaches.)

Alexander Marshak
NASA’s Goddard Space Flight Center
alexander.marshak@nasa.gov


Adam Szabo
NASA’s Goddard Space Flight Center
adam.szabo@nasa.gov

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      NASA astronaut Kate Rubins works on Selectable Optical Diagnostics Instrument Experiment Diffusion Coefficient Mixture-3 (SODI) DCMix-3 installation inside the station’s Microgravity Science Glovebox.JAXA (Japan Aerospace Exploration Agency)/Takuya Onishi Research validates ferrofluid technology

      Researchers validated the concept of using ferrofluid technology to operate a thermal control switch in a spacecraft. This outcome could support development of more reliable and long-lasting spacecraft thermal management systems, increasing mission lifespan and improving crew safety.

      Überflieger 2: Ferrofluid Application Research Goes Orbital analyzed the performance of ferrofluids, a technology that manipulates components such as rotors and switches using magnetized liquids and a magnetic field rather than mechanical systems, which are prone to wear and tear. This technology could lower the cost of materials for thermal management systems, reduce the need for maintenance and repair, and help avoid equipment failure. The paper discusses possible improvements to the thermal switch, including optimizing the geometry to better manage heat flow.
      A view of the Ferrofluid Application Research Goes Orbital investigation hardware aboard the International Space Station. UAE (United Arab Emirates)/Sultan AlneyadiView the full article
    • By NASA
      3 min read
      Preparations for Next Moonwalk Simulations Underway (and Underwater)
      Regolith Adherence Characterization, or RAC, is one of 10 science and technology instruments flying on NASA’s next Commercial Lunar Payload Services (CLPS) flight as part of the Blue Ghost Misison-1. Developed by Aegis Aerospace of Webster, Texas, RAC is designed to study how lunar dust reacts to more than a dozen different types of material samples, located on the payload’s wheels. Photo courtesy Firefly Aerospace The Moon may look like barren rock, but it’s actually covered in a layer of gravel, pebbles, and dust collectively known as “lunar regolith.” During the Apollo Moon missions, astronauts learned firsthand that the fine, powdery dust – electromagnetically charged due to constant bombardment by solar and cosmic particles – is extremely abrasive and clings to everything: gloves, boots, vehicles, and mechanical equipment. What challenges does that dust pose to future Artemis-era missions to establish long-term outposts on the lunar surface?
      That’s the task of an innovative science instrument called RAC-1 (Regolith Adherence Characterization), one of 10 NASA payloads flying aboard the next delivery for the agency’s CLPS (Commercial Lunar Payload Services) initiative and set to be carried to the surface by Firefly Aerospace’s Blue Ghost 1 lunar lander.
      Developed by Aegis Aerospace of Webster, Texas, RAC will expose 15 sample materials – fabrics, paint coatings, optical systems, sensors, solar cells, and more – to the lunar environment to determine how tenaciously the lunar dust sticks to each one. The instrument will measure accumulation rates during landing and subsequent routine lander operations, aiding identification of those materials which best repel or shed dust. The data will help NASA and its industry partners more effectively test, upgrade, and protect spacecraft, spacesuits, habitats, and equipment in preparation for continued exploration of the Moon under the Artemis campaign.
      “Lunar regolith is a sticky challenge for long-duration expeditions to the surface,” said Dennis Harris, who manages the RAC payload for NASA’s CLPS initiative at the agency’s Marshall Space Flight Center in Huntsville, Alabama. “Dust gets into gears, sticks to spacesuits, and can block optical properties. RAC will help determine the best materials and fabrics with which to build, delivering more robust, durable hardware, products, and equipment.”
      Under the CLPS model, NASA is investing in commercial delivery services to the Moon to enable industry growth and support long-term lunar exploration. As a primary customer for CLPS deliveries, NASA aims to be one of many customers on future flights. NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the development of seven of the 10 CLPS payloads carried on Firefly’s Blue Ghost lunar lander.
      Learn more about. CLPS and Artemis at:
      https://www.nasa.gov/clps
      Alise Fisher
      Headquarters, Washington
      202-358-2546
      Alise.m.fisher@nasa.gov
      Headquarters, Washington
      202-358-2546
      Alise.m.fisher@nasa.gov
      Corinne Beckinger 
      Marshall Space Flight Center, Huntsville, Ala. 
      256-544-0034  
      corinne.m.beckinger@nasa.gov 
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      Last Updated Dec 20, 2024 EditorBeth RidgewayContactCorinne M. Beckingercorinne.m.beckinger@nasa.govLocationMarshall Space Flight Center Related Terms
      Commercial Lunar Payload Services (CLPS) Artemis Marshall Space Flight Center Explore More
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    • By NASA
      A rendering of Firefly’s Blue Ghost lunar lander and a rover developed for the company’s third mission to the Moon as part of NASA’s CLPS (Commercial Lunar Payload Services) initiative.Credit: Firefly Aerospace NASA continues to advance its campaign to explore more of the Moon than ever before, awarding Firefly Aerospace $179 million to deliver six experiments to the lunar surface. This fourth task order for Firefly will target landing in the Gruithuisen Domes on the near side of the Moon in 2028.
      As part of the agency’s broader Artemis campaign, Firefly will deliver a group of science experiments and technology demonstrations under NASA’s CLPS initiative, or Commercial Lunar Payload Services, to these lunar domes, an area of ancient lava flows, to better understand planetary processes and evolution. Through CLPS, NASA is furthering our understanding of the Moon’s environment and helping prepare for future human missions to the lunar surface, as part of the agency’s Moon to Mars exploration approach. 
      “The CLPS initiative carries out U.S. scientific and technical studies on the surface of the Moon by robot explorers. As NASA prepares for future human exploration of the Moon, the CLPS initiative continues to support a growing lunar economy with American companies,” said Joel Kearns, deputy associate administrator for exploration, Science Mission Directorate, NASA Headquarters in Washington. “Understanding the formation of the Gruithuisen Domes, as well as the ancient lava flows surrounding the landing site, will help the U.S. answer important questions about the lunar surface.”
      Firefly’s first lunar delivery is scheduled to launch no earlier than mid-January 2025 and will land near a volcanic feature called Mons Latreille within Mare Crisium, on the northeast quadrant of the Moon’s near side. Firefly’s second lunar mission includes two task orders: a lunar orbit drop-off of a satellite combined with a delivery to the lunar surface on the far side and a delivery of a lunar orbital calibration source, scheduled in 2026.
      This new delivery in 2028 will send payloads to the Gruithuisen Domes and the nearby Sinus Viscositatus. The Gruithuisen Domes have long been suspected to be formed by a magma rich in silica, similar in composition to granite. Granitic rocks form easily on Earth due to plate tectonics and oceans of water. The Moon lacks these key ingredients, so lunar scientists have been left to wonder how these domes formed and evolved over time. For the first time, as part of this task order, NASA also has contracted to provide “mobility,” or roving, for some of the scientific instruments on the lunar surface after landing. This will enable new types of U.S. scientific investigations from CLPS.
      “Firefly will deliver six instruments to understand the landing site and surrounding vicinity,” said Chris Culbert, manager of the CLPS initiative at NASA’s Johnson Space Center in Houston. “These instruments will study geologic processes and lunar regolith, test solar cells, and characterize the neutron radiation environment, supplying invaluable information as NASA works to establish a long-term presence on the Moon.”
      The instruments, collectively expected to be about 215 pounds (97 kilograms) in mass, include: 
      Lunar Vulkan Imaging and Spectroscopy Explorer, which consists of two stationary and three mobile instruments, will study rocks and regoliths on the summit of one of the domes to determine their origin and better understand geologic processes of early planetary bodies. The principal investigator is Dr. Kerri Donaldson Hanna of the University of Central Florida, Orlando. Heimdall is a flexible camera system that will be used to take pictures of the landing site from above the horizon to the ground directly below the lander. The principal investigator is Dr. R. Aileen Yingst of the Planetary Science Institute, Tucson, Arizona. Sample Acquisition, Morphology Filtering, and Probing of Lunar Regolith is a robotic arm that will collect samples of lunar regolith and use a robotic scoop to filter and isolate particles of different sizes. The sampling technology will use a flight spare from the Mars Exploration Rover project. The principal investigator is Sean Dougherty of Maxar Technologies, Westminster, Colorado. Low-frequency Radio Observations from the Near Side Lunar Surface is designed to observe the Moon’s surface environment in radio frequencies, to determine whether natural and human-generated activity near the surface interferes with science. The project is headed up by Natchimuthuk Gopalswamy of NASA’s Goddard Space Flight Center in Greenbelt, Maryland.  Photovoltaic Investigation on the Lunar Surface will carry a set of the latest solar cells for a technology demonstration of light-to-electricity power conversion for future missions. The experiment will also collect data on the electrical charging environment of the lunar surface using a small array of solar cells. The principal investigator is Jeremiah McNatt from NASA’s Glenn Research Center in Cleveland. Neutron Measurements at the Lunar Surface is a neutron spectrometer that will characterize the surface neutron radiation environment, monitor hydrogen, and provide constraints on elemental composition. The principal investigator is Dr. Heidi Haviland of NASA’s Marshall Spaceflight Center in Huntsville, Alabama. Through the CLPS initiative, NASA purchases lunar landing and surface operations services from American companies. The agency uses CLPS to send scientific instruments and technology demonstrations to advance capabilities for science, exploration, or commercial development of the Moon. By supporting a robust cadence of lunar deliveries, NASA will continue to enable a growing lunar economy while leveraging the entrepreneurial innovation of the commercial space industry. Two upcoming CLPS flights scheduled to launch in early 2025 will deliver NASA payloads to the Moon’s near side and south polar region, respectively.
      Learn more about CLPS and Artemis at:
      https://www.nasa.gov/clps
      -end-
      Alise Fisher
      Headquarters, Washington
      202-358-2546
      alise.m.fisher@nasa.gov
      Natalia Riusech / Nilufar Ramji    
      Johnson Space Center, Houston
      281-483-5111
      natalia.s.riusech@nasa.gov / nilufar.ramji@nasa.gov
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      Last Updated Dec 18, 2024 LocationNASA Headquarters Related Terms
      Commercial Lunar Payload Services (CLPS) Artemis View the full article
    • By NASA
      4 min read
      NASA Open Science Reveals Sounds of Space
      A composite image of the Crab Nebula features X-rays from Chandra (blue and white), optical data from Hubble (purple), and infrared data from Spitzer (pink). This image is one of several that can be experienced as a sonification through Chandra’s Universe of Sound project. X-ray: NASA/CXC/SAO; Optical: NASA/STScI; Infrared: NASA-JPL-Caltech NASA has a long history of translating astronomy data into beautiful images that are beloved by the public. Through its Chandra X-ray Observatory and Universe of Learning programs, NASA brings that principle into the world of audio in a project known as “A Universe of Sound.” The team has converted openly available data from Chandra, supplemented by open data from other observatories, into dozens of “sonifications,” with more on the way.
      Following the open science principle of accessibility, “A Universe of Sound” helps members of the public who are blind or low vision experience NASA data in a new sensory way. Sighted users also enjoy listening to the sonifications. 
      “Open science is this way to not just have data archives that are accessible and incredibly rich, but also to enhance the data outputs themselves,” said Dr. Kimberly Arcand, the visualization scientist and emerging technology lead at Chandra and member of NASA’s Universe of Learning who heads up the sonification team. “I want everybody to have the same type of access to this data that I do as a scientist. Sonification is just one of those steps.”
      Data sonification of the Milky Way galactic center, made using data from NASA’s Chandra X-ray Observatory, Hubble Space Telescope, and Spitzer Space Telescope. While the Chandra telescope provides data in X-ray wavelengths for most of the sonifications, the team also took open data from other observatories to create a fuller picture of the universe. Types of data used to create some of the sonifications include visual and ultraviolet light from the Hubble Space Telescope, infrared and visual light from the James Webb Space Telescope, and infrared light from the now-retired Spitzer Space Telescope. 
      The sonification team, which includes astrophysicist Matt Russo, musician Andrew Santaguida (both of the SYSTEM Sounds project), consultant Christine Malec, and Dr. Arcand, assigned each wavelength of observation to a different musical instrument or synthesized sound to create a symphony of data. Making the separate layers publicly available was important to the team to help listeners understand the data better. 
      “It’s not just about accessibility. It’s also about reproducibility,” Arcand said. “We’re being very specific with providing all of the layers of sound, and then describing what those layers are doing to make it more transparent and obvious which steps were taken and what process of translation has occurred.” 
      For example, in a sonification of the supernova remnant Cassiopeia A, modified piano sounds represent X-ray data from Chandra, strings and brass represent infrared data from Webb and Spitzer, and small cymbals represent stars located via visual light data from Hubble. 
      Data sonification of the Cassiopeia A supernova remnant, made using data from NASA’s Chandra X-ray Observatory, James Webb Space Telescope, and Hubble Space Telescope. The team brought together people of various backgrounds to make the project a success – scientists to obtain and interpret the data, audio engineers to mix the sonifications, and members of the blind and low vision community to direct the product into something that brought a greater understanding of the data. 
      “Another benefit to open science is it tends to open those pathways of collaboration,” Arcand said. “We invite lots of different community members into the process to make sure we’re creating something that adds value, that adds to the greater good, and that makes the investment in the data worthwhile.” 
      A documentary about the sonifications called “Listen to the Universe” is hosted on NASA+. Visitors can listen to all the team’s sonifications, including the separate layers from each wavelength of observation, on the Universe of Sound website.
      By Lauren Leese 
      Web Content Strategist for the Office of the Chief Science Data Officer 
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      Last Updated Dec 17, 2024 Related Terms
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