Lei Ji (CTR)

Spatially explicit estimation of aboveground boreal forest biomass in the Yukon River Basin, Alaska

Quantification of aboveground biomass (AGB) in Alaska’s boreal forest is essential to the accurate evaluation of terrestrial carbon stocks and dynamics in northern high-latitude ecosystems. Our goal was to map AGB at 30 m resolution for the boreal forest in the Yukon River Basin of Alaska using Landsat data and ground measurements. We acquired Landsat images to generate a 3-year (2008–2010) composite of top-of-atmosphere reflectance for six bands as well as the brightness temperature (BT). We constructed a multiple regression model using field-observed AGB and Landsat-derived reflectance, BT, and vegetation indices. A basin-wide boreal forest AGB map at 30 m resolution was generated by applying the regression model...

Categories: Publication; Types: Journal Citation; Tags: Alaska, Boreal forest, Boreal forest biomass, Forest biomass, Yukon River Basin

Water management starts with the understanding of the spaciotemporal distribution of the available water, uses, and losses. A planet with limited water resources needs accurate, reliable and frequently-updated data and tools to assess and monitor historical and current uses and plan for future needs. Scientists at EROS harness massive amounts of satellite and global weather datasets and integrate them with agro-hydroloic models to create multi-scale products for use by resource managers and researchers across the world for improved decision making and scenario building in water, agriculture, and natural resources. Agro-hydrologic research focuses on hydrologic processes between 2-m below and 2-m above the ground...

Tags: Africa, Core Science Systems, Data and Information Assets, EROS Visible Infrared Imaging Radiometer Suite (eVIIRS), Evapotranspiration, All tags... Geospatial Applications, Global, LANDSAT, USA, Water Use and Availability Science, Water use, Water, Coasts and Ice, Fewer tags

We developed an improved approach to the parameterization of the Operational Simplified Surface Energy Balance (SSEBop) model using the Forcing and Normalizing Operation (FANO). The FANO parameterization was implemented on two computing platforms using Landsat and gridded meteorological datasets: 1) Google Earth Engine (GEE) and 2) Earth Resources Observation and Science (EROS) Center Science Processing Architecture (ESPA). Evaluation was conducted by comparing modeled actual evapotranspiration (ETa) estimates with AmeriFlux Eddy Covariance (EC) and water balance ETa from level-8 Hydrologic Unit Code sub-basins in the conterminous United States for five water-years (Oct-Sep; 2009, 2011, 2013, 2016, 2018). The results...

Categories: Data; Types: Map Service, OGC WFS Layer, OGC WMS Layer, OGC WMS Service; Tags: CONUS, Consumptive Use, Evapotranspiration, Hydrology, Landsat, All tags... Remote Sensing, USGS Science Data Catalog (SDC), Water Resources, Water Use, Fewer tags

Assessment of temporal trends in vegetation greenness and related influences aids understanding of recent changes in terrestrial ecosystems and feedbacks from weather, climate, and environment. We analyzed 1-km normalized difference vegetation index (NDVI) time series data (1989–2016) derived from the Advanced Very High Resolution Radiometer (AVHRR) and developed growing-season time-integrated NDVI (GS-TIN) for estimating seasonal vegetation activity across stable natural land cover in the conterminous United States (CONUS). After removing areas from analysis that had experienced land-cover conversion or modification, we conducted a monotonic trend analysis on the GS-TIN time series and found that significant positive...

Categories: Publication; Types: Downloadable, Map Service, OGC WFS Layer, OGC WMS Layer, OGC WMS Service; Tags: Climate variability, Regression analysis, Remote Sensing, Satellite observations, Temperature, All tags... Trends, United States, Vegetation–precipitation interactions, preciptation, Fewer tags

Characterization of water use and water balance for the croplands of Kansas using satellite, climate, and irrigation data

Kansas is one of the most productive agricultural states in the United States, where agricultural irrigation is a primary user of underground and surface water. Because of low precipitation and declining groundwater levels in western and central Kansas, sustainable management of irrigation water resources is a critical issue in the agricultural productivity of the state. The objective of this study is to analyze and characterize the water use and water balance in the croplands of Kansas using satellite observations, meteorological data, and in situ irrigation water use records. We used actual evapotranspiration (ETa), precipitation, soil moisture, and irrigation water use to calculate water balance for Kansas in...

Categories: Publication; Types: Downloadable, Map Service, OGC WFS Layer, OGC WMS Layer, OGC WMS Service; Tags: Kansas, cropland, irrigation, pumping data, remote sensing, All tags... water balance, water use, Fewer tags