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Remote Sensing of The Surface Temperature of the Great Salt Lake

Remote Sensing of The Surface Temperature of the Great Salt Lake. Erik T. Crosman John D. Horel University of Utah NOAA Cooperative Institute for Regional Prediction GSA 2005 Annual Meeting

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Remote Sensing of The Surface Temperature of the Great Salt Lake

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  1. Remote Sensing of The Surface Temperature of the Great Salt Lake Erik T. Crosman John D. Horel University of Utah NOAA Cooperative Institute for Regional Prediction GSA 2005 Annual Meeting The Hydrosystem of the Great Salt Lake Basin: New Frontiers for Observing And Modeling Human-impacted Hydrologic, Climatic, and Geomorphologic processes II GSA 2005 Salt Lake Annual Meeting

  2. Outline • Motivation and Methodology • Sources of Error • Case Studies • Summary and Future Work GSA 2005 Salt Lake Annual Meeting

  3. Research Goals • Use remote sensing data (AVHRR, MODIS) to characterize the lake state: level, temperature, salinity, turbidity, etc. • Investigate the impact of lake state on local weather (e.g., lake breeze, lake-effect snowstorms) • Future- examine regional and remote climate forcing on the Great Salt Lake GSA 2005 Salt Lake Annual Meeting

  4. Impacts of lake temperature on local weather and climate • Lake state forces and is forced by the meteorology of the region on many different time scales. Zumpfe and Horel JAM 2006 GSA 2005 Salt Lake Annual Meeting

  5. Methodology • Advanced Very High Resolution Radiometer (AVHRR) images at 1.1 km resolution from NOAA polar orbiting satellites 1981-present • Three visible channels used for daytime cloud identification and two infrared channels used for cloud identification and temperature • Infrared data calibrated and converted to brightness temperature • Split-window techniques used to correct for the effects of atmospheric water vapor for surface temperature • Lake temperature retrievals measure “skin” temperature of infinitesimally thin surface layer • Accuracy of AVHRR sea surface temperature retrievals approximately +/- 0.5 oC based on comparison to ocean buoys

  6. Outline • Motivation and Methodology • Sources of Error • Case Studies • Summary and Future Work GSA 2005 Salt Lake Annual Meeting

  7. Sources of error GSA 2005 Salt Lake Annual Meeting

  8. Impact of salinity on emissivity CHANNEL 4 – CHANNEL 5 BRIGHTNESS TEMPERATURE south arm salinity 13% north arm salinity 26% For large zenith angle (64 degrees) GSA 2005 Salt Lake Annual Meeting

  9. Outline • Motivation and Methodology • Sources of Error • Case Studies • Summary and Future Work GSA 2005 Salt Lake Annual Meeting

  10. Freshwater lens Surface temperature 13 May 2005 2220 UTC MODIS true color 2035 UTC MODIS true color 1855 UTC GSA 2005 Salt Lake Annual Meeting

  11. Variable mixing Cooler water noted in regions where winds were stronger 10 March 1839 UTC GSA 2005 Salt Lake Annual Meeting 2112 UTC

  12. Northerly winds Southerly winds GSA 2005 Salt Lake Annual Meeting

  13. Day October 6, 2005 Lake Surface Diurnal Temperature Variability Night October 6, 2005 GSA 2005 Salt Lake Annual Meeting

  14. Lake Surface Temperature Variability Oct 1 2005 Night Oct 5 2005 Night

  15. Annual temperature cycle obtained from AVHRR (1981-2004) and in situ measurements South arm temperature data courtesy of J.W. Gwynn, Utah Geological Survey Annual Cycle GSA 2005 Salt Lake Annual Meeting

  16. Beyond lake temperature • Satellite data likely will give valuable information on lake state beyond temperature • Salinity • Turbidity • Currents, lens, circulations 23 June 2005 6 June 2004 GSA 2005 Salt Lake Annual Meeting

  17. 5-6 NOV 2004 : Lake circulation feature 5 November MODIS true color AVHRR ch 1 AVHRR ch 2 AVHRR LST 6 November GSA 2005 Salt Lake Annual Meeting

  18. Winds interacting with bay inflow23 June 2005 Channel 1 reflectance Surface temperature GSA 2005 Salt Lake Annual Meeting

  19. Summary and Future Work • Satellite imagery is useful for studying • 1) spatial and temporal variability of Great Salt Lake temperature • 2) interactions between lake temperature and limnological and meteorological forcing • 3) other characteristics of lake state (salinity, turbidity) • Satellite-derived surface temperature may be useful for examining lake-climate interactions • Further validation studies (buoy/platform?) required to minimize errors in AVHRR and MODIS satellite-derived surface temperature • Use AVHRR/MODIS data to quantify relationship between lake surface temperature and weather and climate forcing • Use MODIS data to better understand lake state (7 additional visible channels; 2 additional thermal channels) GSA 2005 Salt Lake Annual Meeting

  20. For further information-www.met.utah.edu/research/saltlake GSA 2005 Salt Lake Annual Meeting

  21. Advanced Very High Resolution Radiometer (AVHRR) thermal retrievals 1981-present 1.1 km nadir resolution 6 channels (five operational) Channel 1 (.58-.58 microns; visible) Channel 2 (.73-1.0 microns; visible) Channel 3a (1.58-1.64 microns; visible) Channel 3b (3.55-3.93 microns) Channel 4 (10.3-11.3 microns; thermal IR) Channel 5 (11.5-12.5 microns; thermal IR) Visible channels used for daytime cloud masking; infrared channels for deriving lake surface temperature Future use: MODIS and ATSR-2 DATA AVHRR Pre-processed data obtained from CoastWatch: --cloud and land masks --derived SST CoastWatch visualization software version 3.6 GSA 2005 Salt Lake Annual Meeting

  22. Controls of lake surface temperature GSA 2005 Salt Lake Annual Meeting

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