GLOBAL LAKE SURFACE TEMPERATURES FROM ATSR

摘要

The ATSR Reprocessing for Climate - Lake (ARCLake)rnproject applies optimal estimation (OE) retrievalsrnand probabilistic cloud screening methods to providernlake surface water temperature (LSWT) estimates fromrnthe series of (Advanced) Along-Track ScanningrnRadiometers. This methodology is generic (i.e.rnapplicable to all lakes) as variations in physicalrnproperties such as elevation, salinity, and atmosphericrnconditions are accounted for through the forwardrnmodelling of observed radiances.rnLSWTs have been obtained for 258 of Earth’s largestrnlakes from ATSR-1, ATSR-2 and AATSR imageryrnfrom 1991 to 2011. A subset of 164 lakes providernsuitable time-series for analysis of climatic trends.rnComparison of satellite and buoy summer temperaturerntrends yields good agreement (a root mean squarerndiscrepancy of 0.035 ℃ yr-1 across trends for 15rnlocations in six lakes). Analysing 164 large lakesrnworldwide, there is a decadal trend of 0.05 ℃ yr-1 inrnsummer temperatures for lakes north of 30°N, andrnessentially zero mean trend elsewhere. This is consistentrnwith a previous report covering 1985 to 2009 for 113rnlarge inland waters; however, inter-annual variability inrnnorthern hemisphere summer mean LSWT is markedlyrngreater in our time-series.rnThis paper provides an overview of the ARC-Lakernproject, its publically available data products, andrnresults from analysis of summer temperature trends overrnthe past 20 years. It also presents example applicationsrnof the ARC-Lake LSWTs, including: climatology, lakernmodelling, and numerical weather prediction.