Christopher Potter

• Doctor of Philosophy
• National Aeronautics and Space Administration

Ecosystems in the North American Arctic-Boreal Zone (ABZ) experience a diverse set of disturbances associated with wildfire, permafrost dynamics, geomorphic processes, insect outbreaks and pathogens, extreme weather events, and human activity. Climate warming in the ABZ is occurring at over twice the rate of the global average, and as a result the...

The SCU Lightning Complex Fire started on 16 August 2020 and burned more than 395,000 acres of woodlands and grasslands in six California counties. Satellite images of pre-fire green vegetation biomass from both 2020 springtime (moist) and summertime (drier) periods, along with slope and aspect were used as predictors of burn severity patterns on t...

Alaska’s boreal forest is facing unprecedented challenges under rapid climate warming (increasingly severe fires, droughts, pest/disease outbreaks) that may destabilize its function as a global carbon sink. Forests near Fairbanks may be especially vulnerable, impacting air quality and ecosystem services. We combined GT (ground truthing) with Airbor...

The catastrophic flooding of New Orleans following landfall of Hurricane Katrina in August of 2005 left behind a unique urban environment for investigating disaster impacts on vegetation disturbance and recovery. The goal of this study was to analyze the changes in urban tree canopy cover (both live standing and downed) and the extent of vegetation...

The city of New Orleans is still recovering from Hurricane Katrina and continues to experience numerous negative effects from the lingering storm damage to its urban forest cover. The goal of this study was to analyze recent changes in area coverage of all trees, shrubs, and herbaceous lawns in neighborhoods of New Orleans, particularly in three of...

The purpose of this study was to make quantitative connections between changes in social and economic activities in northern California urban areas and related Earth system environmental responses to the COVID-19 pandemic in 2020. We tested the hypothesis that the absence of worker activities during Shelter-in-Place in the San Francisco Bay Area de...

Plain Language Summary Carbon dioxide (CO2) is a greenhouse gas that plays a predominant role in climate change. Volcanoes emit CO2 and play a role in the global carbon cycle; however, the amount of CO2 they emit is highly uncertain. One of the main reasons for this uncertainty is the limited amount of volcanic emission measurements available to es...

Potter, C. and Amer, R., 0000. Mapping 30 years of change in the marshlands of Breton Sound basin (southeastern Louisiana, U.S.A.): Coastal land area and vegetation green cover. Journal of Coastal Research, 00(0), 000-000. Coconut Creek (Florida), ISSN 0749-0208. This study analyzes the 30-year record of Landsat satellite imagery to better understa...

Trends and geographic patterns of change in vegetation phenology metrics and snowmelt timing from the MODerate resolution Imaging Spectroradiometer (MODIS) satellite data sets were analyzed across the state of Alaska for all wildfires that burned during the years 2004 and 2005. Phenology metric patterns (over the period 2000 to 2018) derived from t...

Understanding trends in vegetation phenology and growing season productivity at a regional scale is important for global change studies, particularly as linkages can be made between climate shifts and the vegetation’s potential to sequester or release carbon into the atmosphere. Trends and geographic patterns of change in vegetation growth and phen...

Potter, C. and Amer, R., 0000. Mapping 30 years of change in the marshlands of Breton Sound basin (southeastern Louisiana, U.S.A.): Coastal land area and vegetation green cover. Journal of Coastal Research, 00(0), 000-000. Coconut Creek (Florida), ISSN 0749-0208. This study analyzes the 30-year record of Landsat satellite imagery to better understa...

Context Trends and geographic patterns of change in vegetation phenology metrics and snowmelt timing from the MODerate resolution Imaging Spectroradiometer (MODIS) satellite data sets were analyzed for the Northern Range of Yellowstone National Park over the period 2001 to 2017. Objectives The main question posed in this analysis was “Where has th...

Trends and transitions in the growing season Normalized Difference Vegetation Index (NDVI) from the MODerate resolution Imaging Spectroradiometer (MODIS) satellite sensor at 250-m resolution were analyzed for the period from 2000 to 2018 to understand recent patterns of vegetation change in ecosystems of the Noatak National Preserve in northwestern...

This study assesses the impact of different state of the art global biospheric CO2 flux models, when applied as prior information, on inverse model “top-down” estimates of terrestrial CO2 fluxes obtained when assimilating Orbiting Carbon Observatory 2 (OCO-2) observations. This is done with a series of observing system simulation experiments (OSSEs...

In the deserts of Southern California, air temperatures have been rising and precipitation variability has been increasing over the past several decades. These recent climate shifts may have begun to threaten the survival of certain plant and animal species in these arid ecosystems. This study was designed to quantify and characterize variations in...

Trends and transitions in the MODerate resolution Imaging Spectroradiometer (MODIS) Normalized Difference Vegetation Index (NDVI) time series at 250-m resolution were analyzed for the period from 2000 to 2018 to understand recent patterns of vegetation change in Yellowstone National Park (USA). Statistical change in the NDVI time series was detecte...

Forest ecosystems have been increasingly affected by a variety of disturbances, including emerging infectious diseases (EIDs), causing extensive tree mortality in the Western United States. Especially over the past decade, EID outbreaks occurred more frequently and severely in forest landscapes, which have killed large numbers of trees. While tree...

Trends and transitions in the growing-season normalized difference vegetation index (NDVI) from the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite sensor at 250-m resolution were analyzed for the period from 2000 to 2018 to understand recent patterns of vegetation change in ecosystems of the Arctic National Wildlife Refuge (ANWR) i...

New solar energy facilities on public lands in the deserts of southern California are being monitored long-term to detect environmental impacts. For this purpose, we have developed a framework for detecting changes in vegetation cover region-wide using greenness index data sets from the Moderate Resolution Imaging Spectroradiometer (MODIS) satellit...

The land surface temperature (LST) in arid regions is a primary controller of many ecological processes. Consequently, we have developed a framework for detection of LST change on a regional scale using data sets covering all deserts of southern California from the Moderate-Resolution Imaging Spectroradiometer (MODIS) satellite sensor. The Breaks f...

This study assesses the impact of different state-of-the-science global biospheric CO2 flux models, when applied as prior information, on inverse modeling top-down estimates of terrestrial CO2 fluxes obtained when assimilating Orbiting Carbon Observatory 2 (OCO-2) observations. This is done with a series of Observing System Simulation Experiments (...

The purpose of this study was to better understand the relationships between diurnal variations of air temperature measured hourly at the soil surface, compared with the thermal infra-red (TIR) emission properties of soil surfaces located in the Lower Colorado Desert of California, eastern Riverside County. Fifty air temperature loggers were deploy...

In the summer of 2015, hundreds of forest fires burned across the state of Alaska. Several uncontrolled wildfires near the town of Tanana on the Yukon River were responsible for the largest portion of the area burned statewide. In July 2017, field measurements were carried out in both unburned and burned forested areas nearly adjacent to one anothe...

Biological soil crusts (biocrusts) are composed of a combination of cyanobacteria, green algae, lichens, and mosses that can protect arid soil surfaces from erosive forces. The presence of biocrusts in desert regions is influenced by a complex interaction of climatic, edaphic, and topographic variables, but their distribution and coverage densities...

The analysis of wildfire impacts at the scale of less than a square kilometer can reveal important patterns of vegetation recovery and regrowth in freshwater Arctic and boreal regions. For this study, NASA Landsat burned area products since the year 2000, and a near 20-year record of vegetation green cover from the MODIS (Moderate Resolution Imagin...

Impacts of the extreme 2013 to 2014 drought on vegetation canopy cover in the Big Sur region of central coastal California were assessed using a combination of satellite image analysis and in situ measurements of soil moisture. Landsat and moderate resolution imaging spectroradiometer satellite images were analyzed and compared across six ecosystem...

Background: In the summer of 2015, hundreds of wildfires burned across the state of Alaska, and consumed more than 1.6 million ha of boreal forest and wetlands in the Yukon-Koyukuk region. Mapping of 113 large wildfires using Landsat satellite images from before and after 2015 indicated that nearly 60% of this area was burned at moderate-to-high s...

Coffee is an important crop in tropical regions of the world; about 125 million people depend on coffee agriculture for their livelihoods. Understanding the spatial extent of coffee fields is useful for management and control of coffee pests such as Hypothenemus hampei and other pests that use coffee fruit as a host for immature stages such as the...

There is mounting evidence that fire size and severity have been growing on the central and southern California coastal landscape over the past several decades. Landsat satellite data was analyzed for the 20 largest fires on the Central California coast since 1984 to determine the relationships between climate/weather conditions at the time of igni...

Landsat imagery was analyzed to understand changes in subalpine forest stands since the mid-1980s in the Sierra Nevada region of California. At locations where long-term plot measurements have shown that stands are becoming denser in the number of small tree stems (compared with the early 1930s), the 30-year analysis of normalized difference vegeta...

Fog water deposition may be an important component of the water budget of herbaceous-shrub ecosystems on the central and southern coastal regions of California. This paper presents the first analysis of measured fog water drip rates and meteorological controls in shrublands of Big Sur, California. Seasonal totals of 1255 mm and 306 mm of fog water...

Potential disturbance of desert soils from renewable energy development in southern California is receiving increasing attention due to potential impacts on air quality and greenhouse gas emissions. This study was designed to quantify and map, for the first time, changes in desert pavement surface area using 20 years of Landsat satellite image data...

Background: To improve estimates of net primary production for terrestrial ecosystems of the continental United States, we evaluated a new image fusion technique to incorporate high resolution Landsat land cover data into a modified version of the CASA ecosystem model. The proportion of each Landsat land cover type within each 0.004 degree resolut...

The Santa Cruz Mountains is a coastal landscape with a history of extensive forest logging, and a future with projected climate warming that may alter vegetation cover and surface water runoff in new ways. Results from Landsat satellite image time-series analysis since 1983 of this study area showed gradual, statistically significant increases in t...

Landsat satellite imagery at 30-m ground resolution was analyzed for Glacier National Park (GNP) Montana (United States of America) to determine when and where canopy green cover had changed significantly across the National Park area since the mid- 1980s. Image comparisons for the years 1984 and 2010 showed that consistent increases in the normali...

Developers of renewable energy installations in southern California need to evaluate the risks to facility operations from proximity to active desert dunes. This study first validated Landsat image spectral data using ground-based data collection of aeolian sand migration rate measurements surveyed in Arizona as an accurate method for characterizin...

Developers of renewable energy installations in Southern California must monitor the impacts of operations of new facilities on fragile desert ecosystems. This study is the first to use Landsat satellite spectral data to map changes in the distribution of biological soil crusts (BSCs) across federal lands of the Lower Colorado Desert. The coverage...

The potential for negative effects such as habitat loss and high severity wildfires on endemic and threatened biological resources on the United States Pacific coast from recent climate warming has received increasing attention. This study was designed to quantify, for the first time, variations in forest and coastal bluff scrub canopy density and...

The Soberanes Fire started on July 22, 2016 in Monterey County on the California Central Coast from an illegal campfire. This disastrous fire burned for 10 weeks at a record cost of more than $208 million for protection and control. A progressive analysis of the normalized burn ratio from the Landsat satellite showed that the final high burn severi...

The Sierra Nevada of California is a region where large forest fires have been suppressed for over a century and future climate warming has the potential to alter vegetation cover and surface water runoff. A detailed geographic record of recent changes in vegetation cover across the Sierra Nevada remains a gap that can be filled with satellite remo...

A methodology was developed to assess the impacts of the historic 2013-2014 drought on ecosystems of California's Central Coast region, using a combination of satellite image analysis and in situ measurements of soil moisture in predominant vegetation types of the region. According to differences in Landsat drought indices for plant water stress an...

Analysis of Landsat satellite images was applied to detect changes in forest and woodland vegetation cover in Santa Clara County, California. Results showed that 92 km2 (22,730 acres) of forests and woodlands were highly disturbed in SCC between 1999 and 2009, 37% (34 km2) of which did not overlap with any known wildland fire boundaries, and hence,...

Rapid recovery of pioneer shrub and forest patch cover can reduce soil erosion, nutrient runoff and degradation of stream habitats, and promote small mammal and avian biodiversity following stand-replacing wildfires. Landsat imagery from the past 25+ years was analyzed to understand patterns and rates of vegetation recovery, focusing on high burn s...

Vegetation Cover Change in Yellowstone National Park Detected using Landsat Satellite Image Analysis The northern Rocky Mountains are a region where future climate warming has the potential to alter vegetation cover and surface water runoff. Results from Landsat satellite image analysis since 1987 in all unburned areas (since the 1880s) of Yellowst...

Changes in Meadow Vegetation Cover in Yosemite National Park (California) Based on Three Decades of Landsat Image Analysis Meadow ecosystems can serve as sensitive indicators of climate change impacts on the Sierra Nevada region. Landsat 30-m resolution image data over the past 25 years in Yosemite National Park was analyzed to track changes in the...

The Sierra Nevada of California is a region where large wildfires have been suppressed for over a century. A detailed geographic record of recent vegetation regrowth and disturbance patterns in forests of the Sierra Nevada remains a gap that can be filled with remote-sensing data. Landsat Thematic Mapper imagery was analysed to detect 10 years of r...

Trends in the growing season Moderate Resolution Imaging Spectroradiometer (MODIS) Enhanced Vegetation Index (EVI) time-series were analyzed for the time period from 2000 to 2010 to understand landscape-level patterns of vegetation change in ecosystems of interior Alaska. The analysis compared data-sets for Alaska vegetation cover types, wetland co...

There is a long history of livestock grazing on the California Central Coast, dating back over 150 years. In this study, methods were reviewed and results presented for analysis of NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) satellite sensor data to monitor year-to-year variation of forage production on Central Coast rangelands aro...

This study reports on the first comprehensive global assessment of tropical storm (TS) impacts on coastal ecosystem vegetation along the landfall pathways of major hurricanes, cyclones and typhoons using satellite data of land cover vegetation for the years 2006 to 2012. Wind damage has been shown to reduce live vegetation pools of carbon, accelera...

Field sampling and satellite remote sensing were used to test the hypothesis that site microclimate variability leading to divergent soil water use by vegetation types is closely associated with variability in annual net primary productivity (NPP) at the landscape scale. A simulation model based on satellite observations of seasonal phenology was u...

A new process-based simulation model to estimate methane emissions from Amazon floodplain ecosystems is described and evaluated in comparison to independent measurements of methane fluxes. The model’s three major components are 1) types of wetland vegetation and the changes in water level, temperature and dissolved oxygen of flooded areas, 2) plant...

The majority of weather station records indicate that surface air temperatures have been warming in California between 1950 and 2005. Temperature data from the mid-1990s to the present were analyzed for stations on California Central Coast near Big Sur (Monterey County) to better understand potential for climate change in this biologically unique r...

This study describes the application of the NASA version of the Carnegie‐Ames‐Stanford Approach (CASA) ecosystem model coupled with a surface hydrologic routing scheme previously called the Hydrological Routing Algorithm (HYDRA) to model monthly discharge rates from 2000 to 2007 on the Merced River drainage in Yosemite National Park, California. To...

Landsat satellite imagery was analyzed to generate a detailed record of 10 years of vegetation disturbance and regrowth for Pacific coastal areas of Marin and San Francisco Counties. The Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS) methodology, a transformation of Tasseled-Cap data space, was applied to detected changes in pere...

Landsat satellite imagery was analyzed to generate a detailed record of 10 years of vegetation disturbance and regrowth for Pacific coastal areas of San Mateo and Santa Cruz Counties. The Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS) methodology, a transformation of Tasseled-Cap data space, was applied to detected changes in per...

Trends in Alaska ecosystem carbon fluxes were predicted from inputs of monthly MODerate resolution Imaging Spectroradiometer (MODIS) vegetation index time-series combined with the NASA-CASA (Carnegie Ames Stanford Approach) carbon cycle simulation model over the past decade. CASA simulates monthly net ecosystem production (NEP) as the difference in...

The objective of this study was to demonstrate a new, cost-effective method to define the sustainable amounts of harvested wood products in Southeast Asian countries case studies, while avoiding degradation (net loss) of total wood carbon stocks. Satellite remote sensing from the MODIS sensor was used in the CASA (Carnegie Ames Stanford Approach) c...

Trends in the monthly moderate resolution Imaging Spectroradiometer (MODIS) Enhanced Vegetation Index (EVI) time-series were analyzed for tundra ecosystems of Alaska over the past decade. Results showed that 10% of all tundra-dominated areas in Alaska were detected with significant (p<0.05) positive or negative MODIS growing season EVI trends from...

The Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS) methodology was applied to detect changes in perennial vegetation cover at marshland sites in Northern California reported to have undergone restoration between 1999 and 2009. Results showed extensive contiguous areas of restored marshland plant cover at 10 of the 14 sites select...

The CASA (Carnegie-Ames-Stanford) ecosystem model has been used to estimate monthly carbon fluxes in terrestrial ecosystems from 2000 to 2009, with global data inputs from NASA’s Terra Moderate Resolution Imaging Spectroradiometer (MODIS) vegetation cover mapping. Net primary production (NPP) flux for atmospheric carbon dioxide has varied slightly...

Forests are an important natural resource that support economic activity and play a significant role in regulating the climate and the carbon cycle, yet forest ecosystems are increasingly threatened by fires caused by a range of natural and anthropogenic factors. Mapping these fires, which can range in size from less than an acre to hundreds of tho...

Segmentation of a time series attempts to divide it into homogeneous subsequences, such that each of these segments are different from each other. A typical segmentation framework involves selecting a model that is used to represent the segment. In this paper, we investigate segmentation scores based on difference between models and propose two app...

The density of lodgepole pine (Pinus contorta) sapling regeneration was mapped in areas burned during the 1988 wildfires across Yellowstone National Park (YNP), Wyoming, USA. Hyperspectral image analysis and field measurements were combined across the entire YNP extent. Airborne Visible Infrared Imaging Spectrometer (AVIRIS) image data from 2006 we...

An evaluation of ALOS PALSAR (Phased Array type L-band Synthetic Aperture Radar) data for shrub height and aboveground biomass (AGB) estimation has been performed in scrub-dominated ecosystems of central coastal California. Comparison between AGB field measurements and SAR estimations showed a correlation coefficient of R-2 = 0.53 for the HV polari...

In this study, we present results from the CASA (Carnegie-Ames-Stanford Approach) model to estimate net primary production (NPP) in grasslands under different management (ranching versus unmanaged) on the Central Coast of California. The latest model version called CASA Express has been designed to estimate monthly patterns in carbon fixation and p...

A simulation model to estimate net primary pro-ductivity (NPP) has been combined with in situ measurements of soil carbon dioxide (CO 2) emissions and leaf litter pools in three coast redwood forest stands on the central California coast. Monthly NPP was predicted from the CASA model using 250-meter resolution vegeta-tion index (VI) inputs. Annual...

The CASA (Carnegie-Ames-Stanford) ecosystem model based on satellite greenness observations has been used to es-timate monthly carbon fluxes in terrestrial ecosystems from 2000 to 2009. The CASA model was driven by NASA Moderate Resolution Imaging Spectroradiometer (MODIS) vegetation cover properties and large-scale (1 km resolution) disturbance ev...

Remote sensing techniques can provide information on habitat quality, biodiversity, and cover change at the regional scales of sagebrush-steppe dominated systems and with the repeatability necessary for resource management. In this paper, we present the results of multiple endmember spectral mixture analysis applied to Advanced Spaceborne Thermal E...

Negative trends in the monthly MODerate resolution Imaging Spectroradiometer (MODIS) Enhanced Vegetation Index (EVI) time-series were found to be widespread in natural (non-cropland) ecosystems of the eastern United States from 2000 to 2010. Four sub-regions were detected with significant declines in summed growing season (May-September) EVI, namel...

Fog deposition is a notable component of the water budget of herbaceous-shrub ecosystems on the central and southern coastal regions of California. This paper presents an analysis of fog water deposition rates and meteorological controls in Big Sur, California. Mesh-screen fog collectors were installed the Brazil Ranch weather station sites to meas...

Many components of the carbon cycle are constrained by a variety of remote sensing measurements. Observations of land surface parameters constrain estimates of carbon flux from terrestrial biosphere models while estimates of oceanic carbon fluxes are informed by satellite observations of ocean color and ocean properties. Atmospheric CO2 concentrati...

The goal of NASA Carbon Monitoring Study (CMS) Flux Pilot Project is to incorporate the full suite of NASA observational, modeling, and assimilation capabilities to assess the role NASA satellite remote sensing can play in the attribution of changes in globally distributed CO2 concentrations to the carbon cycle and anthropogenic emissions. To that...

NASA's Carbon Monitoring System (CMS) flux pilot project combines NASA's Earth System models in land, ocean and atmosphere to track surface CO2 fluxes. The system is constrained by atmospheric measurements of XCO2 from the Japanese GOSAT satellite, giving a "big picture" view of total CO2 in Earth's atmosphere. Combining two land models (CASA-Ames...

The emission of carbon dioxide from deforestation and other land cover changes is among the most uncertain components of the global carbon cycle. Inconsistent and unverified information about global deforestation patterns has significant implications for balancing the present-day carbon budget and predicting the future evolution of climate change....

1] Forest disturbances greatly alter the carbon cycle at various spatial and temporal scales. It is critical to understand disturbance regimes and their impacts to better quantify regional and global carbon dynamics. This review of the status and major challenges in representing the impacts of disturbances in modeling the carbon dynamics across Nor...

A simulation model based on remote sensing data for spatial vegetation properties has been used to estimate ecosystem carbon fluxes across Yellowstone National Park (YNP). The CASA (Carnegie Ames Stanford Approach) model was applied at a regional scale to estimate seasonal and annual carbon fluxes as net primary production (NPP) and soil respiratio...

Forests are a critical component of the planet's ecosystem. Unfortunately, there has been significant degradation in forest cover over recent decades as a result of logging, conversion to crop, plantation, and pasture land, or disasters (natural or man made) such as forest fires, floods, and hurricanes. As a result, significant attention is being g...

GOPHER (Global Observation of Planetary Health and Ecosystem Resources) is a collection of data mining algorithms for detecting global land use and land cover change that builds on a decade of research on spatio temporal data mining at the University of Minnesota; the GOPHER approach to analyzing remote sensing imagery provides such a solution by p...

Satellite remote sensing was combined with the NASA-CASA (Carnegie Ames Stanford Approach) carbon cycle simulation model to evaluate the impact of the 2010 drought (July through September) throughout tropical South America. Results indicated that net primary production in Amazon forest areas declined by an average of 7% in 2010 compared to 2008. Th...

Long distance migrations by ungulate species often surpass the boundaries of preservation areas where conflicts with various publics lead to management actions that can threaten populations. We chose the partially migratory bison (Bison bison) population in Yellowstone National Park as an example of integrating science into management policies to b...

It is well-known that forests play a vital role in maintaining biodiversity and the health of ecosystems across the Earth. This important ecological resource is under threat from both anthropogenic and biogenic pressures, ranging from insect infestations to commercial logging. Detecting, quantifying and reporting the magnitude of forest degradation...

Ecosystem-related observations from remote sensors on satellites offer significant possibility for understanding the location and extent of global land cover change. In this paper, we focus on time series segmentation techniques in the context of land cover change detection. We propose a model-based time series segmentation algorithm inspired by an...

The ability to monitor forest related change events like forest fires, deforestation for agriculture intensification, and logging is critical for effective forest management. Time series remote sensing data sets such as MODIS Enhanced Vegetation Index (EVI) can be used to identify these changes. Most existing approaches work on small data sets span...

The CASA (Carnegie-Ames-Stanford) ecosystem model based on satellite greenness observations has been used to estimate monthly carbon fluxes in terrestrial ecosystems from 2000 to 2009. The CASA model was driven by NASA Moderate Resolution Imaging Spectroradiometer (MODIS) vegetation cover properties and large-scale (1-km resolution) disturbance eve...

The ability to detect changes in forest cover is of critical importance for both economic and scientific reasons, e.g. using forests for economic carbon sink management and studying natural and anthropogenic impacts on ecosystems. The contribution of greenhouse gases from deforestation is one of the most uncertain elements of the global carbon cycl...

This study describes applications of the Carnegie-Ames-Stanford Approach (CASA) ecosystem model coupled with a surface hydrologic routing scheme previously called the Hydrological Routing Algorithm (HYDRA) to model river discharge rates across selected California watersheds in the North Coast region of the state. For mountainous areas, CASA-HYDRA s...

Massive degradation in forest cover over recent decades caused by natural and human activities has made ability to detect changes in forest cover of critical importance. This paper provides a brief overview of our research on identifying changes in forest cover.

The carbon budget of a region can be defined as the sum of annual fluxes of carbon dioxide (CO2) and methane (CH4) greenhouse gases (GHGs) into and out of the regional surface coverage area. According to the state government's recent inventory, California's carbon budget is presently dominated by 115 MMTCE per year in fossil fuel emissions of CO2 (...

The western United States is under invasion from cheatgrass (Bromus tectorum L.), an annual grass that alters the pattern of phenology in the ecosystems it infests. This study was conducted to investigate methods for monitoring this invasion. As a result of its annual phenology, cheatgrass is not only an extremely competitive invader, it is also de...

River discharge rates across all California's watershed have been modeled using the NASA version of the Carnegie-Ames-Stanford Approach (CASA) ecosystem model coupled with a surface hydrologic routing scheme previously called the Hydrological Routing Algorithm (HYDRA). To assess CASA-HYDRA's capability to estimate actual water flows in extreme and...

The arid and semi-arid sagebrush–grass ecosystem occupies a substantial portion of rangelands in the western United States. Using remote sensing techniques to map the percent of sagebrush, grass/forb, and bare ground components is necessary for forage production estimation and natural resource management over large areas. However optical data have...

Ecosystem-related observations from remote sensors on satellites offer huge potential for understanding the location and extent of global land cover change. This paper presents a comparative study of three time series based algorithms for detecting changes in land cover. The techniques are evaluated quantitatively using forest fire ground truth fro...