Jump to content

SARP East 2024 Ocean Remote Sensing Group


Recommended Posts

  • Publishers
Posted

8 min read

Preparations for Next Moonwalk Simulations Underway (and Underwater)

Faculty Advisors:

Dr. Tom Bell, Woods Hole Oceanographic Institution

Dr. Kelsey Bisson, NASA Headquarters Science Mission Directorate

Graduate Mentor:

Kelby Kramer, Massachusetts Institute of Technology

Kelby Kramer, Graduate Mentor

Kelby Kramer, graduate mentor for the 2024 SARP Ocean Remote Sensing group, provides an introduction for each of the group members and shares behind-the scenes moments from the internship.

Lucas DiSilvestro

Shallow Water Benthic Cover Type Classification using Hyperspectral Imagery in Kaneohe Bay, Oahu, Hawaii

Lucas DiSilvestro

Quantifying the changing structure and extent of benthic coral communities is essential for informing restoration efforts and identifying stressed regions of coral. Accurate classification of shallow-water benthic coral communities requires high spectral and spatial resolution, currently not available on spaceborne sensors, to observe the seafloor through an optically complex seawater column. Here we create a shallow water benthic cover type map of Kaneohe Bay, Oahu, Hawaii using the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) without requiring in-situ data as inputs. We first run the AVIRIS data through a semi-analytical inversion model to derive color dissolved organic matter, chlorophyll concentration, bottom albedo, suspended sediment, and depth parameters for each pixel, which are then matched to a Hydrolight simulated water column. Pure reflectance for coral, algae, and sand are then projected through each water column to create spectral endmembers for each pixel. Multiple Endmember Spectral Mixture Analysis (MESMA) provides fractional cover of each benthic class on a per-pixel basis. We demonstrate the efficacy of using simulated water columns to create surface reflectance spectral endmembers as Hydrolight-derived in-situ endmember spectra strongly match AVIRIS surface reflectance for corresponding locations (average R = 0.96). This study highlights the capabilities of using medium-fine resolution hyperspectral imagery to identify fractional cover type of localized coral communities and lays the groundwork for future spaceborne hyperspectral monitoring of global coral communities.

Atticus Cummings

Quantifying Uncertainty In Kelp Canopy Remote Sensing Using the Harmonized Landsat Sentinel-2 Dataset

Atticus Cummings

California’s giant kelp forests serve as a major foundation for the region’s rich marine biodiversity and provide recreational and economic value to the State of California. With the rising frequency of marine heatwaves and extreme weather onset by climate change, it has become increasingly important to study these vital ecosystems. Kelp forests are highly dynamic, changing across several timescales; seasonally due to nutrient concentrations, waves, and predator populations, weekly with typical growth and decay, and hourly with the tides and currents. Previous remote sensing of kelp canopies has relied on Landsat imagery taken with a eight-day interval, limiting the ability to quantify more rapid changes. This project aims to address uncertainty in kelp canopy detection using the Harmonized Landsat and Sentinel-2 (HLS) dataset’s zero to five-day revisit period. A random forest classifier was used to identify pixels that contain kelp, on which Multiple Endmember Spectral Mixture Analysis (MESMA) was then run to quantify intrapixel kelp density. Processed multispectral satellite images taken within 3 days of one another were paired for comparison. The relationship between fluctuations in kelp canopy density with tides and currents was assessed using in situ data from an acoustic doppler current profiler (ADCP) at the Santa Barbara Long Term Ecological Research site (LTER) and a NOAA tidal buoy. Preliminary results show that current and tidal trends cannot be accurately correlated with canopy detection due to other sources of error. We found that under cloud-free conditions, canopy detection between paired images varied on average by 42%. Standardized image processing suggests that this uncertainty is not created within the image processing step, but likely arises due to exterior factors such as sensor signal noise, atmospheric conditions, and sea state. Ultimately, these errors could lead to misinterpretation of remotely sensed kelp ecosystems, highlighting the need for further research to identify and account for uncertainties in remote sensing of kelp canopies.

Jasmine Sirvent

Kelp Us!: A Methods Analysis for Predicting Kelp Pigment Concentrations from Hyperspectral Reflectance

Jasmine Sirvent

Ocean color remote sensing enables researchers to assess the quantity and physiology of life in the ocean, which is imperative to understanding ecosystem health and formulating accurate predictions. However, without proper methods to analyze hyperspectral data, correlations between spectral reflectance and physiological traits cannot be accurately derived. In this study, I explored different methods—single variable regression, partial least squares regressions (PLSR), and derivatives—in analyzing in situ Macrocystis pyrifera (giant kelp) off the coast of Santa Barbara, California in order to predict pigment concentrations from AVIRIS hyperspectral reflectance. With derivatives as a spectral diagnostic tool, there is evidence suggesting high versus low pigment concentrations could be diagnosed; however, the fluctuations were within 10 nm of resolution, thus AVIRIS would be unable to reliably detect them. Exploring a different method, I plotted in situ pigment measurements — chlorophyll a, fucoxanthin, and the ratio of fucoxanthin to chlorophyll a—against hyperspectral reflectance that was resampled to AVIRIS bands. PLSR proved to be a more successful model because of its hyperdimensional analysis capabilities in accounting for multiple wavelength bands, reaching R2 values of 0.67. Using this information, I constructed a model that predicts kelp pigments from simulated AVIRIS reflectance using a spatial time series of laboratory spectral measurements and photosynthetic pigment concentrations. These results have implications, not only for kelp, but many other photosynthetic organisms detectable by hyperspectral airborne or satellite sensors. With these findings, airborne optical data could possibly predict a plethora of other biogeochemical traits. Potentially, this research would permit scientists to acquire data analogous to in situ measurements about floating matters that cannot financially and pragmatically be accessed by anything other than a remote sensor.

Isabelle Cobb

Correlations Between SSHa and Chl-a Concentrations in the Northern South China Sea

Isabelle Cobb

Sea surface height anomalies (SSHa)–variations in sea surface height from climatological averages–occur on seasonal timescales due to coastal upwelling and El Niño-Southern Oscillation (ENSO) cycles. These anomalies are heightened when upwelling plumes bring cold, nutrient-rich water to the surface, and are particularly strong along continental shelves in the Northern South China Sea (NSCS). This linkage between SSHa and nutrient availability has interesting implications for changing chlorophyll-a (chl-a) concentrations, a prominent indicator of phytoplankton biomass that is essential to the health of marine ecosystems. Here, we evaluate the long-term (15 years) relationship between SSHa and chl-a, in both satellite remote sensing data and in situ measurements. Level 3 SSHa data from Jason 1/2/3 satellites and chl-a data from MODIS Aqua were acquired and binned to monthly resolution. We found a significant inverse correlation between SSHa and chl-a during upwelling months in both the remote sensing (Spearman’s R=-0.57) and in situ data, with higher resolution in situ data from ORAS4 (an assimilation of buoy observations from 2003-2017) showing stronger correlations (Spearman’s R=-0.75). In addition, the data reveal that the magnitude of SSH increases with time during instances of high correlation, possibly indicating a trend of increased SSH associated with reduced seasonal chl-a concentrations. Thus, this relationship may inform future work predicting nutrient availability and threats to marine ecosystems as climate change continues to affect coastal sea surface heights.

Alyssa Tou

Exploring Coastal Sea Surface Temperature Anomalies and their effect on Coastal Fog through analyzing Plant Phenology

Alyssa Tou

Marine heat waves (MHW) have been increasing in frequency, duration and intensity, giving them substantial potential to influence ecosystems. Do these MHWs sufficiently enhance coastal precipitation such that plant growth is impacted? Recently, the Northeast Pacific experienced a long, intense MHW in 2014/2015, and another short, less intense MHW in 2019/2020. Here we investigate how the intensity and duration of MHWs influence the intensity and seasonal cycle of three different land cover types (‘grass’, ‘trees’, and a combination of both ‘combined’’) to analyze plant phenology trends in Big Sur, California. We hypothesize that longer intense MHWs decrease the ocean’s evaporative capacity, decreasing fog, thus lowering plant productivity, as measured by Normalized Difference Vegetation Index (NDVI). Sea surface temperature (SST) and NDVI data were collected from the NOAA Coral Reef Watch, and NASA MODIS/Terra Vegetation Indices 16-Day L3 Global 250m products respectively. Preliminary results show no correlation (R2=0.02) between SSTa and combined NDVI values and no correlation (R2=0.01) between SST and NDVI. This suggests that years with anomalously high SST do not significantly impact plant phenology. During the intense and long 2014/2015 MHW, peak NDVI values for ‘grass’ and ‘combined’ pixels were 2.0 and 1.7 standard deviations above the climatological average, while the shorter 2019/2020 MHW saw higher peaks of 3.2 and 2.4 standard deviations. However, the ‘grass’, ‘tree’ and ‘combined’ NDVI anomalies were statistically insignificant during both MHWs, showing that although NDVI appeared to increase during the shorter and less intense MHW, these values may be attributed to other factors. The data qualitatively suggest that MHW’s don’t impact the peak NDVI date, but more data at higher temporal resolution are necessary. Further research will involve analyzing fog indices and exploring confounding variables impacting NDVI, such as plant physiology, anthropogenic disturbance, and wildfires. In addition, it’s important to understand to what extent changes in NDVI are attributed to the driving factors of MHWs or the MHWs themselves. Ultimately, mechanistically understanding the impacts MHW intensity and duration have on terrestrial ecosystems will better inform coastal community resilience.

Share

Details

Last Updated
Nov 22, 2024

Related Terms

View the full article

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Similar Topics

    • By NASA
      NASA Expert Answers Your Questions About Asteroid 2024 YR4
    • By NASA
      Explore This SectionEarth Home Earth Observer Home Editor’s Corner Feature Articles Meeting Summaries NewsScience in the News Calendars In Memoriam MoreArchives 3 min read
      In Memoriam: Jeff Dozier [1944–2024]
      Jeff Dozier [1944–2024]Photo credit: Dozier’s family obituary Jeff Dozier, an environmental scientist, snow hydrologist, researcher, academic – and former Earth Observing System Project Scientist – died on November 17, 2024. Jeff’s research focused on snow hydrology and biogeochemistry in mountain environments and addressed the role of stored and melting snow in the hydrologic cycle as well as the economic and social impact on water resources. In these efforts, he embraced remote sensing with satellites to measure snow properties and energy balance. He was a Project Scientist with the Earth Observing System (EOS) Data and Information System, contributing to the design and management of very large information systems that would impact spatial modeling and environmental informatics.
      Jeff served as the second EOS Project Scientist from 1990–1992. During that time, he worked with the NASA science community to – in his own words – “accomplish the goals of EOS, the most important of which is to develop the capability to predict or assess plausible environmental changes – both natural and human-induced – that will occur in the future. Meeting this challenge for the next decade to century requires the integration of knowledge from the traditional disciplines and information from many different sources into a coherent view of the Earth system. EOS is the largest project in the history of NASA and arguably the most important national and international scientific mission of the next two decades.”
      Jeff’s work alongside Michael Matson, was featured in a 2019 NASA Earth Science news article: “NASA Tracks Wildfires From Above to Aid Firefighters Below.” While working at NOAA’s National Environmental Satellite, Data, and Information Service building in Camp Springs, MD, the pair detected methane fires in the Persian Gulf using the Advanced Very High Resolution Radiometer (AVHRR) instrument on the NOAA-6 satellite – marking the first time that such a small fire had been seen from space. Jeff went on to develop a mathematical method to distinguish small fires from other sources of heat, which become the foundation for nearly all subsequent satellite fire-detection algorithms. 
      At the time of his death, Jeff was Principal Investigator of a NASA-funded project with the objective of testing whether data from the Earth Surface Mineral Dust Source Investigation (EMIT) mission could be used to help refine the estimate for the snowpack melting rate. In the 2024 Earth Science news article, “NASA’s EMIT Will Explore Diverse Science Questions on Extended Mission,” Jeff indicated that EMIT’s ability to ‘see’ well into the infrared (IR) spectrum of light is key to his group’s efforts because ice is “pretty absorptive at near-IR and shortwave-IR wavelengths.” The results from this research will help inform water management decisions in states, such as California, where meltwater makes up the majority of the agricultural water supply.
      Jeff earned a Bachelor’s of Science degree from California State University, Hayward (now California State University, East Bay) and a Master’s of Science degree and Ph.D. from the University of Michigan. He spent his career teaching at the University of California, Santa Barbara (UCSB), where he was named the founding Dean of the Bren School of Environmental Science and Management at UCSB in 1994. As the Dean, he recruited renowned faculty and developed one of the top environmental programs in the country. After his role as Dean, Jeff returned as a professor at Bren, educating the next generation of Earth scientists.
      Jeff Dozier [1944–2024]Photo credit: Dozier’s family obituaryView the full article
    • By NASA
      Explore This SectionEarth Home Earth Observer Home Editor’s Corner Feature Articles Meeting Summaries NewsScience in the News Calendars In Memoriam MoreArchives 3 min read
      In Memoriam: Berrien Moore III [1941–2024]
      Berrien Moore III [1941–2024]Photo credit: Moore’s obituary on the University of Oklahoma’s (OU) website Berrien Moore III, Dean of the College of Atmospheric and Geographic Sciences at the University of Oklahoma (OU), director of the National Weather Center in Norman, OK, and Vice President for Weather and Climate Programs, died on December 17, 2024. Berrien earned an undergraduate degree from the University of North Carolina in 1963 and a doctorate degree from the University of Virginia in 1969. After graduating, he taught mathematics at the University of New Hampshire (UNH) and became tenured in 1976. 
      In 1987, Berrien became director of the Institute for the Study of Earth, Oceans, and Space (ISEOS) at UNH. NASA chose ISEOS to be one of the 24 founding members of the “Working Prototype Federation” of Earth Science Information Partners (ESIP) in 1998. Still active more than 25 years later, ESIP is now a thriving nonprofit entity funded by cooperative agreements with NASA, the National Oceanic and Atmospheric Administration (NOAA), and the U.S. Geological Survey, which brings together interdisciplinary collaborations (among over 170 partners) to share technical knowledge and engage with data users.
      Berrien left UNH in 2008, to serve as the founding Executive Director of Climate Central, a think-tank based in Princeton, NJ, which is dedicated to providing objective and understandable information about climate change
      Berrien moved to OU in 2010. Given his diverse academic, research, and career experience in global carbon cycle, biogeochemistry, remote sensing, environmental and space policy, and mathematics, Berrien was a natural choice to become the architect and principal investigator for the Geostationary Carbon Cycle Observatory (GeoCARB), a proposed NASA Earth Venture Mission that would have monitored plant health and vegetation stress throughout the Americas from geostationary orbit, probing natural sources, sinks, and exchange processes that control carbon dioxide, carbon monoxide, and methane in the atmosphere. While the mission was ultimately cancelled, the lessons learned are being applied to similar current and future Earth observing endeavors, e,g, NASA’s ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) mission.
      Berrien served on and chaired numerous government-affiliated scientific committees throughout his career. From 1995–1998 he served on the National Research Council’s Committee on Global Change Research, which produced the landmark report, “Global Environment Change: Research Pathways for the Next Decade.” In 2011, he was an author on the National Research Council’s (NRC) decadal survey, “Earth Science and Applications from Space: A Community Assessment and Strategies for the Future.”
      Berrien participated on international scientific committees as well. From 1998–2002, he was the chair of the Science Committee of the International Geosphere Biosphere Programme (IGBP). He was also a lead author within the Intergovernmental Panel on Climate Change’s Third Assessment Report, which was released in 2001.
      Berrien served in several roles specific to NASA, including as a committee member and later chair of the organization’s Space and Earth Science Advisory Committee. He served as Chair of the Earth Observing System (EOS) Payload Advisory Committee, member and Chair of NASA’s Earth Science and Applications Committee, and member of the NASA Advisory Council. He was also active at NOAA, having chaired the agency’s Research Review Team and served on the Research and Development Portfolio Review Team for NOAA’s Science Advisory Board. 
      Berrien received NASA’s highest civilian honor, the Distinguished Public Service Medal, for outstanding service and the NOAA Administrator’s Recognition Award. He also received the 2007 Dryden Lectureship in Research Medal from the American Institute of Aeronautics and Astronautics and was honored for his contributions to the IPCC when the organization received the 2007 Nobel Peace Prize.
      View the full article
    • By NASA
      Explore This Section Earth Home Earth Observer Home Editor’s Corner Feature Articles Meeting Summaries News Science in the News Calendars In Memoriam More Archives 3 min read
      In Memoriam: Pierre Morel [1933–2024]
      Pierre Morel [1933–2024] Photo Credit: Morel’s obituary on the Ecole Normale Supérieure website Pierre Morel, the first director of the World Climate Research Programme (WCRP) and founding member of WCRP’s Global Energy and Water Exchanges (GEWEX) Core project, died on December 10, 2024.
      Pierre began his research as a theoretical physicist. His doctoral thesis examined the existence and properties of a condensed superfluid state of liquid Helium 3 at very low temperature. He lectured on basic physics, geophysical fluid dynamics, and climate science. As his career progressed, he focused his research on studying the circulation of the atmosphere. He was devoted to the development of numerical modelling of atmospheric flow that laid the groundwork for the study of climatology.
      Pierre’s work played an integral role in the development of tools used to study the atmosphere, many of which are still active today. Examples include Project Éole – an experimental wind energy plant conceived in the 1980s and created in Quebec, Canada that closed down in 1993; the ARGOS satellite, a collaboration between the Centre National d’Études Spatiale (CNES) [French Space Agency], National Oceanic and Atmospheric Administration (NOAA), and NASA, to collect and relay meteorological and oceanographic data around the world that launched in 1978; the Search and Rescue Satellite Aided Tracking (SARSAT) system, which was developed by the U.S. – specifically NOAA, NASA, and the U.S. Coast Guard and Air Force – Canada, and France, with the first satellite launch in 1982; and the European Organization for the Exploitation of Meteorological Satellites’ METEOSAT series of geostationary satellites, which launched in 1977 and remain active today. The launch of Meteosat–12 in 2022 was the first METEOSAT Third Generation (MTG) launch.
      Early in his career, Pierre was the director of the French Laboratoire de Météorologie Dynamique (LMD) before he became the director of the Centre National d’Études Spatiales (CNES). In 1980 he became the first chairman of the WCRP, where he steered a broad interdisciplinary research program in global climate and Earth system science that involved the participation of atmospheric, oceanic, hydrological, and polar scientists worldwide. Pierre was later in charge of planetary programs at NASA and was involved in discussions about the future of NASA’s Earth Observing System (EOS) in the mid-to-late 1990s. As an example, the Earth Observer article, “Minutes Of The Fourteenth Earth Science Enterprise/Earth Observing System (ESE/EOS) Investigators Working Group Meeting,” includes a summary of a presentation Pierre gave that focused on flight mission planning for the EOS “second series,” which was NASA’s plan at the time although ultimately not pursued, with the “first series” (i.e., Terra, Aqua, Aura) enduring much longer than anticipated.
      Pierre was the recipient of the 2008 Alfred Wegener Medal & Honorary Membership for his outstanding contributions to geophysical fluid dynamics, his leadership in the development of climate research, and the applications of space observation to meteorology and the Earth system science.
      View the full article
    • By Space Force
      The U.S. Space Force announced the winners of the third annual Polaris Awards, recognizing individuals and teams who embody the four Guardian Values: Character, Connection, Commitment, and Courage.
      View the full article
  • Check out these Videos

×
×
  • Create New...