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By NASA
6 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
NASA instruments and aircraft are helping identify potential sources of critical minerals across vast swaths of California, Nevada, and other Western states. Pilots gear up to reach altitudes about twice as high as those of a cruising passenger jet.NASA NASA and the U.S. Geological Survey have been mapping the planets since Apollo. One team is searching closer to home for minerals critical to national security and the economy.
If not for the Joshua trees, the tan hills of Cuprite, Nevada, would resemble Mars. Scalded and chemically altered by water from deep underground, the rocks here are earthly analogs for understanding ancient Martian geology. The hills are also rich with minerals. They’ve lured prospectors for more than 100 years and made Cuprite an ideal place to test NASA technology designed to map the minerals, craters, crusts, and ices of our solar system.
Sensors that discovered lunar water, charted Saturn’s moons, even investigated ground zero in New York City were all tested and calibrated at Cuprite, said Robert Green, a senior research scientist at NASA’s Jet Propulsion Laboratory in Southern California. He’s honed instruments in Nevada for decades.
One of Green’s latest projects is to find and map rocky surfaces in the American West that could contain minerals crucial to the nation’s economy and security. Currently, the U.S. is dependent on imports of 50 critical minerals, which include lithium and rare earth elements used in everything from rechargeable batteries to medicine.
Scientists from the U.S. Geological Survey (USGS) are searching nationwide for domestic sources. NASA is contributing to this effort with high-altitude aircraft and sensors capable of detecting the molecular fingerprints of minerals across vast, treeless expanses in wavelengths of light not visible to human eyes.
The hills of Cuprite, Nevada, appear pink and tan to the eye (top image) but they shine with mica, gypsum, and alunite among other types of minerals when imaged spectroscopically (lower image). NASA sensors used to study Earth and other rocky worlds have been tested there.USGS/Ray Kokaly The collaboration is called GEMx, the Geological Earth Mapping Experiment, and it’s likely the largest airborne spectroscopic survey in U.S. history. Since 2023, scientists working on GEMx have charted more than 190,000 square miles (500,000 square kilometers) of North American soil.
Mapping Partnership Started During Apollo
As NASA instruments fly in aircraft 60,000 feet (18,000 meters) overhead, Todd Hoefen, a geophysicist, and his colleagues from USGS work below. The samples of rock they test and collect in the field are crucial to ensuring that the airborne observations match reality on the ground and are not skewed by the intervening atmosphere.
The GEMx mission marks the latest in a long history of partnerships between NASA and USGS. The two agencies have worked together to map rocky worlds — and keep astronauts and rovers safe — since the early days of the space race.
For example, geologic maps of the Moon made in the early 1960s at the USGS Astrogeology Science Center in Flagstaff, Arizona, helped Apollo mission planners select safe and scientifically promising sites for the six crewed landings that occurred from 1969 to 1972. Before stepping onto the lunar surface, NASA’s Moon-bound astronauts traveled to Flagstaff to practice fieldwork with USGS geologists. A version of those Apollo boot camps continues today with astronauts and scientists involved in NASA’s Artemis mission.
Geophysicist Raymond Kokaly, who leads the GEMx campaign for USGS, is pictured here conducting ground-based hyperspectral imaging of rock in Cuprite, Nevada, in April 2019.USGS/Todd Hoefen The GEMx mission marks the latest in a long history of partnerships between NASA and USGS. The two agencies have worked together to map rocky worlds — and keep astronauts and rovers safe — since the early days of the space race.
Rainbows and Rocks
To detect minerals and other compounds on the surfaces of rocky bodies across the solar system, including Earth, scientists use a technology pioneered by JPL in the 1980s called imaging spectroscopy. One of the original imaging spectrometers built by Robert Green and his team is central to the GEMx campaign in the Western U.S.
About the size and weight of a minifridge and built to fly on planes, the instrument is called AVIRIS-Classic, short for Airborne Visible/Infrared Imaging Spectrometer. Like all imaging spectrometers, it takes advantage of the fact that every molecule reflects and absorbs light in a unique pattern, like a fingerprint. Spectrometers detect these molecular fingerprints in the light bouncing off or emitted from a sample or a surface.
In the case of GEMx, that’s sunlight shimmering off different kinds of rocks.
Compared to a standard digital camera, which “sees” three color channels (red, green, and blue), imaging spectrometers can see more than 200 channels, including infrared wavelengths of light that are invisible to the human eye.
NASA spectrometers have orbited or flown by every major rocky body in our solar system. They’ve helped scientists investigate methane lakes on Titan, Saturn’s largest moon, and study Pluto’s thin atmosphere. One JPL-built spectrometer is currently en route to Europa, an icy moon of Jupiter, to help search for chemical ingredients necessary to support life.
“One of the cool things about NASA is that we develop technology to look out at the solar system and beyond, but we also turn around and look back down,” said Ben Phillips, a longtime NASA program manager who led GEMx until he retired in 2025.
The Newest Instrument
More than 200 hours of GEMx flights are scheduled through fall 2025. Scientists will process and validate the data, with the first USGS mineral maps to follow. During these flights, an ER-2 research aircraft from NASA’s Armstrong Flight Research Center in Edwards, California, will cruise over the Western U.S. at altitudes twice as high as a passenger jet flies.
At such high altitudes, pilot Dean Neeley must wear a spacesuit similar to those used by astronauts. He flies solo in the cramped cockpit but will be accompanied by state-of-the-art NASA instruments. In the belly of the plane rides AVIRIS-Classic, which will be retiring soon after more than three decades in service. Carefully packed in the plane’s nose is its successor: AVIRIS-5, taking flight for the first time in 2025.
Together, the two instruments provide 10 times the performance of the older spectrometer alone, but even by itself AVIRIS-5 marks a leap forward. It can sample areas ranging from about 30 feet (10 meters) to less than a foot (30 centimeters).
“The newest generation of AVIRIS will more than live up to the original,” Green said.
More About GEMx
The GEMx research project will last four years and is funded by the USGS Earth Mapping Resources Initiative. The initiative will capitalize on both the technology developed by NASA for spectroscopic imaging, as well as the agency’s expertise in analyzing the datasets and extracting critical mineral information from them.
Data collected by GEMx is available here.
News Media Contacts
Andrew Wang / Jane J. Lee
Jet Propulsion Laboratory, Pasadena, Calif.
626-379-6874 / 818-354-0307
andrew.wang@jpl.nasa.gov / jane.j.lee@jpl.nasa.gov
Karen Fox / Elizabeth Vlock
NASA Headquarters, Washington
202-358-1600
karen.c.fox@nasa.gov / elizabeth.a.vlock@nasa.gov
Written by Sally Younger
2025-086
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Last Updated Jul 10, 2025 Related Terms
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By NASA
NASA Nearly all of NASA’s ninth class of astronaut candidates, along with two European trainees, poses for photos in the briefing room in the public affairs facility at NASA’s Johnson Space Center in Houston on July 7, 1980.
Group 9 was announced on May 29, 1980; the candidates would go on to make history in spaceflight and at NASA. For example, Charles Bolden (kneeling at far right) traveled to orbit four times aboard the space shuttle between 1986 and 1994, then became the agency’s first African American administrator in 2009. Franklin Chang-Diaz (fifth from the right, standing) was the first Hispanic American to fly in space and Jerry Ross (middle, standing in the back) was the first person to be launched into space seven times.
Image credit: NASA
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By European Space Agency
A new wave of ocean scientists has embarked on an extraordinary six-week voyage aboard a majestic tall ship that set sail today from Norway bound for southern France. But this is no ordinary journey.
Thanks to this ESA Advanced Ocean Training Course, these upcoming researchers will be taking a deep dive into ocean science, empowering them with skills to harness satellite data for research, innovation and sustainable development – and preparing them to become tomorrow’s leaders and ambassadors for ocean science.
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By NASA
8 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
Return to 2024 SARP Closeout 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.
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Last Updated Nov 22, 2024 Related Terms
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By NASA
10 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
Return to 2024 SARP Closeout Faculty Advisors:
Dr. Guanyu Huang, Stony Brook University
Graduate Mentor:
Ryan Schmedding, McGill University
Ryan Schmedding, Graduate Mentor
Ryan Schmedding, graduate mentor for the 2024 SARP Atmospheric Science group, provides an introduction for each of the group members and shares behind-the scenes moments from the internship.
Danielle Jones
Remote sensing of poor air quality in mountains: A case study in Kathmandu, Nepal
Danielle Jones
Urban activity produces particulate matter in the atmosphere known as aerosol particles. These aerosols can negatively affect human health and cause changes to the climate system. Measures for aerosols include surface level PM2.5 concentration and aerosol optical depth (AOD). Kathmandu, Nepal is an urban area that rests in a valley on the edge of the Himalayas and is home to over three million people. Despite the prevailing easterly winds, local aerosols are mostly concentrated in the valley from the residential burning of coal followed by industry. Exposure to PM2.5 has caused an estimated ≥8.6% of deaths annually in Nepal. We paired NASA satellite AOD and elevation data, model meteorological data, and local AirNow PM2.5 and air quality index (AQI) data to determine causes of variation in pollutant measurement during 2023, with increased emphasis on the post-monsoon season (Oct. 1 – Dec. 31). We see the seasonality of meteorological data related to PM2.5 and AQI. During periods of low temperature, low wind speed, and high pressure, PM2.5 and AQI data slightly diverge. This may indicate that temperature inversions increase surface level concentrations of aerosols but have little effect on the total air column. The individual measurements of surface pressure, surface temperature, and wind speed had no observable correlation to AOD (which was less variable than PM2.5 and AQI over the entire year). Elevation was found to have no observable effect on AOD during the period of study. Future research should focus on the relative contributions of different pollutants to the AQI to test if little atmospheric mixing causes the formation of low-altitude secondary pollutants in addition to PM2.5 leading to the observed divergence in AQI and PM2.5.
Madison Holland
Analyzing the Transport and Impact of June 2023 Canadian Wildfire Smoke on Surface PM2.5 Levels in Allentown, Pennsylvania
Madison Holland
The 2023 wildfire season in Canada was unparalleled in its severity. Over 17 million hectares burned, the largest area ever burned in a single season. The smoke from these wildfires spread thousands of kilometers, causing a large population to be exposed to air pollution. Wildfires can release a variety of air pollutants, including fine particulate matter (PM2.5). PM2.5 directly affects human health – exposure to wildfire-related PM2.5 has been associated with respiratory issues such as the exacerbation of asthma and chronic obstructive pulmonary disease. In June 2023, smoke from the Canadian wildfires drifted southward into the United States. The northeastern United States reported unhealthy levels of air quality due to the transportation of the smoke. In particular, Pennsylvania reported that Canadian wildfires caused portions of the state to have “Hazardous” air quality. Our research focused on how Allentown, PA experienced hazardous levels of air quality from this event. To analyze the concentrations of PM2.5 at the surface level, NASA’s Hazardous Air Quality Ensemble System (HAQES) and the EPA’s Air Quality System (AQS) ground-based site data were utilized. By comparing HAQES’s forecast of hazardous air quality events with recorded daily average PM2.5 with the EPA’s AQS, we were able to compare how well the ensemble system was at predicting total PM2.5 during unhealthy air quality days. NOAA’s Hybrid Single-Particle Lagrangian Integrated Trajectory model, pyrsig, and the Canadian National Fire Database were used. These datasets revealed the trajectory of aerosols from the wildfires to Allentown, Pennsylvania, identified the densest regions of the smoke plumes, and provided a map of wildfire locations in southeastern Canada. By integrating these datasets, we traced how wildfire smoke transported aerosols from the source at the ground level.
Michele Iraci
Trends and Transport of Tropospheric Ozone From New York City to Connecticut in the Summer of 2023
Michele Iraci
Tropospheric Ozone, or O₃, is a criteria pollutant contributing to most of Connecticut and New York City’s poor air quality days. It has adverse effects on human health, particularly for high-risk individuals. Ozone is produced by nitrogen oxides and volatile organic compounds from fuel combustion reacting with sunlight. The Ozone Transport Region (OTR) is a collection of states in the Northeast and Mid-Atlantic United States that experience cross-state pollution of O₃. Connecticut has multiple days a year where O₃ values exceed the National Ambient Air Quality Standards requiring the implementation of additional monitoring and standards because it falls in the OTR. Partially due to upstream transport from New York City, Connecticut experiences increases in O₃ concentrations in the summer months. Connecticut has seen declines in poor air quality days from O₃ every year due to the regulations on ozone and its precursors. We use ground-based Lidar, Air Quality System data, and a back-trajectory model to examine a case of ozone enhancement in Connecticut caused by air pollutants from New York between June and August 2023. In this time period, Connecticut’s ozone enhancement was caused by air pollutants from New York City. As a result, New York City and Connecticut saw similar O₃ spikes and decline trends. High-temperature days increase O₃ in both places, and wind out of the southwest may transport O₃ to Connecticut. Production and transport of O₃ from New York City help contribute to Connecticut’s poor air quality days, resulting in the need for interstate agreements on pollution management.
Stefan Sundin
Correlations Between the Planetary Boundary Layer Height and the Lifting Condensation Level
Stefan Sundin
The Planetary Boundary Layer (PBL) characterizes the lowest layer in the atmosphere that is coupled with diurnal heating at the surface. The PBL grows during the day as solar heating causes pockets of air near the surface to rise and mix with cooler air above. Depending on the type of terrain and surface albedo that receives solar heating, the depth of the PBL can vary to a great extent. This makes PBL height (PBLH) a difficult variable to quantify spatially and temporally. While several methods have been used to obtain the PBLH such as wind profilers and lidar techniques, there is still a level of uncertainty associated with PBLH. One method of predicting seasonal PBLH fluctuation and potentially lessening uncertainty that will be discussed in this study is recognizing a correlation in PBLH with the lifting condensation level (LCL). Like the PBL, the LCL is used as a convective parameter when analyzing upper air data, and classifies the height in the atmosphere at which a parcel becomes saturated when lifted by a forcing mechanism, such as a frontal boundary, localized convergence, or orographic lifting. A reason to believe that PBLH and LCL are interconnected is their dependency on both the amount of surface heating and moisture that is present in the environment. These thermodynamic properties are of interest in heavily populated metropolitan areas within the Great Plains, as they are more susceptible to severe weather outbreaks and associated economic losses. Correlations between PBLH and LCL over the Minneapolis-St. Paul metropolitan statistical area during the summer months of 2019-2023 will be discussed.
Angelica Kusen
Coupling of Chlorophyll-a Concentrations and Aerosol Optical Depth in the Subantarctic Southern Ocean and South China Sea (2019-2021)
Angelica Kusen
Air-sea interactions form a complex feedback mechanism, whereby aerosols impact physical and biogeochemical processes in marine environments, which, in turn, alter aerosol properties. One key indicator of these interactions is chlorophyll-a (Chl-a), a pigment common to all phytoplankton and a widely used proxy for primary productivity in marine ecosystems. Phytoplankton require soluble nutrients and trace metals for growth, which typically come from oceanic processes such as upwelling. These nutrients can also be supplied via wet and dry deposition, where atmospheric aerosols are removed from the atmosphere and deposited into the ocean. To explore this interaction, we analyze the spatial and temporal variations of satellite-derived chl-a and AOD, their correlations, and their relationship with wind patterns in the Subantarctic Southern Ocean and the South China Sea from 2019 to 2021, two regions with contrasting environmental conditions.
In the Subantarctic Southern Ocean, a positive correlation (r²= 0.26) between AOD and Chl-a was found, likely due to dust storms following Austrian wildfires. Winds deposit dust aerosols rich in nutrients, such as iron, to the iron-limited ocean, enhancing phytoplankton photosynthesis and increasing chl-a. In contrast, the South China Sea showed no notable correlation (r² = -0.02) between AOD and chl-a. Decreased emissions due to COVID-19 and stricter pollution controls likely reduced the total AOD load and shifted the composition of aerosols from anthropogenic to more natural sources.
These findings highlight the complex interrelationship between oceanic biological activity and the chemical composition of the atmosphere, emphasizing that atmospheric delivery of essential nutrients, such as iron and phosphorus, promotes phytoplankton growth. Finally, NASA’s recently launched PACE mission will contribute observations of phytoplankton community composition at unprecedented scale, possibly enabling attribution of AOD levels to particular groups of phytoplankton.
Chris Hautman
Estimating CO₂ Emission from Rocket Plumes Using in Situ Data from Low Earth Atmosphere
Chris Hautman
Rocket emissions in the lower atmosphere are becoming an increasing environmental concern as space exploration and commercial satellite launches have increased exponentially in recent years. Rocket plumes are one of the few known sources of anthropogenic emissions directly into the upper atmosphere. Emissions in the lower atmosphere may also be of interest due to their impacts on human health and the environment, in particular, ground level pollutants transported over wildlife protected zones, such as the Everglades, or population centers near launch sites. While rockets are a known source of atmospheric pollution, the study of rocket exhaust is an ongoing task. Rocket exhaust can have a variety of compositions depending on the type of engine, the propellants used, including fuels, oxidizers, and monopropellants, the stoichiometry of the combustion itself also plays a role. In addition, there has been increasing research into compounds being vaporized in atmospheric reentry. These emissions, while relatively minimal compared to other methods of travel, pose an increasing threat to atmospheric stability and environmental health with the increase in human space activity. This study attempts to create a method for estimating the total amount of carbon dioxide released by the first stage of a rocket launch relative to the mass flow of RP-1, a highly refined kerosene (C₁₂H₂₆)), and liquid oxygen (LOX) propellants. Particularly, this study will focus on relating in situ CO₂ emission data from a Delta II rocket launch from Vandenberg Air Force Base on April 15, 1999, to CO₂ emissions from popular modern rockets, such as the Falcon 9 (SpaceX) and Soyuz variants (Russia). The findings indicate that the CO₂ density of any RP-1/LOX rocket is 6.9E-7 times the mass flow of the sum of all engines on the first stage. The total mass of CO₂ emitted can be further estimated by modeling the volume of the plume as cylindrical. Therefore, the total mass can be calculated as a function of mass flow and first stage main engine cutoff. Future CO₂ emissions on an annual basis are calculated based on these estimations and anticipated increases in launch frequency.
Return to 2024 SARP Closeout Share
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Last Updated Nov 22, 2024 Related Terms
General Explore More
8 min read SARP East 2024 Ocean Remote Sensing Group
Article 21 mins ago 10 min read SARP East 2024 Hydroecology Group
Article 21 mins ago 11 min read SARP East 2024 Terrestrial Fluxes Group
Article 22 mins ago View the full article
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