Environmental Applications of Low Resolution Remotely Sensed Data

• Published in: Advanced Environmental Monitoring with Remote Sensing Time Series Data and R pp. 67 - 79
• Main Authors: Fang, Bin, Banti, Maria A., Lakshmi, Venkat, Gemitzi, Alexandra
• Format: Book Chapter
• Language: English
• Published: United Kingdom CRC Press 2020; Taylor & Francis Group
• Edition: 1
• Subjects: NDVI Range; NDVI Trend; Terrestrial Water Storage; MODIS Land Product; Grace Signal; Grace Observation; RGB Composite; SMOS Mission; Sensed Normalized Difference Vegetation Index; Vegetation Water Content; MODIS Evapotranspiration; MODIS Tile; Drought Monitoring; RGB Color Composite; MODIS Land; NDWI; RGB; USGS EarthExplorer; Single Channel Algorithm; MODIS Land Surface Temperature Product; MODIS LST; Measured River Discharges; Aqua MODIS; Grace Data; NDVI Series
• ISBN: 0367205270; 9780367205270
• DOI: 10.1201/9780429262050-4

Low resolution remotely sensed environmental data usually correspond to images with a spatial resolution greater than 1 km but often have a pixel size of several kilometers. As those images cover extended geographical areas and provide reasonable temporal frequencies for environmental monitoring, they are regarded as essential parts for operational environmental monitoring while a major advantage is the low cost per unit of surveyed area. Vegetation performance, soil conditions, drought monitoring, flood potential, and terrestrial water storage are among the numerous applications of low resolution remotely sensed products at the regional, continental, or global scale. For detailed environmental studies at the local scale, input from low resolution imagery is used as auxiliary information along with high resolution products and ground measurements to downscale the spatial resolution to the required scale. Although when dealing with remotely sensed missions, the detection of radiation comes to mind, this is not always the case. Therefore, within this chapter we will focus on two major approaches in low resolution remote sensing; the first, which does not measure reflected radiation from Earth, is related to the determination of anomalies of Earth’s gravitational field, while in the second approach soil moisture content is monitored using measurements at the microwave wavelength. Applications of Gravity Recovery and Climate Experiment (GRACE) data are numerous and cover a wide area of environmental aspects. The use of ground monitoring measurements to downscale GRACE data for predictions of groundwater level changes was demonstrated in whereas Gemitzi and Lakshmi developed a methodology to estimate groundwater abstractions at the aquifer scale using GRACE data and auxiliary ground information. The usefulness of GRACE data in assessing flood potential was demonstrated in Reager, Thomas, and Famiglietti, where a relationship between measured river discharges in the Missouri River and GRACE derived total water storage in the whole basin was established. GRACE observations are also useful in monitoring changes in large reservoirs. The GRACE mission supports the observation of co-seismic and post-seismic changes in gravitational field related to large earthquakes as well as the detections of post-seismic relaxation useful to study properties of Earth’s crust and upper mantle.