Analysis of Lake Level and Temperature Variation in the Great Salt Lake using ICESat, MODIS, and In-Situ Data

Many of today's lakes are without in-situ gauges to measure lake level or lake water temperature due to their remote locations. Retrieving this data from individual remote lakes and comparing them to each other is important for investigating changes in climate, anthropological activities, or watershed changes in a particular area. However, it is important to first check the reliability of the remote sensing data by investigating lakes that already have in-situ data and comparing both data sets. This study utilizes remote sensing data from the Ice, Cloud, and Land Elevation Satellite (ICESat) and the Moderate Resolution Imaging Spectrometer (MODIS) onboard the Aqua and Terra satellites. Global Land Surface Altimetry Data (GLA14) from ICESat are compared with in-situ lake level measurements for the Great Salt Lake (GSL) from 2003 to 2009 to check the reliability of the instrument. Both data sets revealed a decreasing trend in lake level with an r^2 value of 0.88 between the ICESat and in-situ data. Thermal imagery (8-daily, 1 km resolution) from MODIS included 818 (1028) images from the Aqua (Terra) satellite from 2002 to 2011 (2000 to 2011). These thermal images were used to calculate the surface water temperature (SWT) of the Great Salt Lake north and south of the railroad causeway which divides the lake in half. After analyzing the data it is evident that the shallower north half of the lake has a higher SWT in the summer and cooler SWT in the winter than the south half by 1 C°. The average monthly SWT and in-situ air temperatures for the GSL are compared well (r^2 value of 0.93) and there is a decreasing trend in air temperatures (from 2002 to 2010), resulting in a decreasing SWT trend for both Terra and Aqua data sets. We conclude there is great potential for the use of satellites to measure lake's characteristics that are usually not possible of using in-situ measurements due to remote or harsh weather conditions.