Fig. 1
Example OSTIA SST field for 1 July 2013 showing (a) global land/sea/lake mask with (b–d) close-ups of regions for detail. Colourbar in K.
Table 1. Accuracy of operational SST algorithms when used for LSWT
NOAA-12 AVHRRNLSSTN. Am. Great LakesNight1.521.27 (SD)2001)NOAA-14 AVHRRMCSSTLake ConstanceDay1.351.352003)NLSSTN. Am. Great LakesNight0.410.80 (SD)2001)NOAA-16 AVHRRMCSSTLake GenevaNight0.180.702005)Lake ConstanceNight−0.280.732005)Lake MondNight−2.081.472005)NLSSTLake GenevaNight1.220.692005)Lake ConstanceNight0.610.642005)Lake MondNight−1.151.342005)NOAA-17 AVHRRMCSSTLake GenevaNight0.700.882005)Lake ConstanceNight−0.041.122005)Lake MondNight−2.031.832005)NLSSTLake GenevaNight1.530.812005)Lake ConstanceNight0.851.122005)Lake MondNight−1.101.912005)MetOp-A AVHRROperationalN. Am. Great LakesNight0.060.50 (SD)A. Marsouin (personal communication, 2009)ATSR-2OperationalVarious N America, Europe, AfricaNight−0.23–0.600.47–0.64 (SD) MacCallum and Merchant (2012) Lake TahoeNight0.690.38 (SD)2003)AATSROperationalVarious N America, EuropeNight−0.54–0.080.83–1.74 (SD) MacCallum and Merchant (2012) Lake TahoeNight−0.410.56 Hulley et al. (2011) Salton SeaDay−0.410.75 Hulley et al. (2011)
Table 2. Accuracy of LSWT algorithms designed for lakes
NOAA-11 AVHRRSplit windowLake MalawiNight−0.020.682001)Triple windowLake MalawiNight−0.170.412001)NOAA-14 AVHRRSplit windowLake ConstanceDay−0.011.042003)Triple windowLake MalawiNight0.060.512001)NOAA-16 AVHRRSplit windowLake ConstanceDay0.160.712003)ATSR-2ARC-Lake OE (N2,N3,D2,D3)Various N America, Europe, AfricaNight−0.04–0.040.53–0.61 (SD) MacCallum and Merchant (2012) N2,N3 (bulk)Lake TahoeNight0.180.18 (SE)2003)N2,N3 (skin)Lake TahoeNight−0.370.28 (SE)2003)AATSRSplit windowLake TahoeNight−0.020.30 Hulley et al. (2011) Split windowSalton SeaDay0.180.46 Hulley et al. (2011) ARC-Lake OE (N2,N3,D2,D3)various N America, EuropeNight−0.31–0.150.46–0.54 (SD) MacCallum and Merchant (2012) ARC-Lake OE LSWT (D3)N. Am. Great LakesNight−0.120.43 (SD) MacCallum and Merchant (2012)
Fig. 2
Total daily number of observations by instrument type for all lakes in OSTIA mask, for JJA 2009.
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Table 3. Observation-minus-background statistics for JJA 2009, for all lakes in global OSTIA mask and three case studies
Global In situ−0.131.02600 AATSR0.080.831826 MetOp-A AVHRR0.201.124740 NOAA-18 AVHRR−0.080.491153Great Lakes In situ−0.141.01498 AATSR0.130.97447 MetOp-A AVHRR0.461.291699 NOAA-18 AVHRR−0.060.55230Lake Baikal In situ−−− AATSR0.491.2035 MetOp-A AVHRR0.421.65159 NOAA-18 AVHRR0.591.147Lake Victoria In situ−−− AATSR0.070.32193 MetOp-A AVHRR0.060.44621 NOAA-18 AVHRR−0.140.30206
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Table 4. OSTIA LSWT minus ARC-Lake observations and ARC-Lake climatology minus ARC-Lake observations for JJA 2009 for selected lakes, listed in order of descending surface area
Observation typeMean diff (K)RMS (K)Mean diff (K)RMS (K)Mean daily no. ARCobs
Global0.651.310.001.784453Great Lakes1.411.780.452.13822Lake Victoria0.400.440.080.29137Lake Baikal1.832.761.212.11140Salton Sea−0.131.45−0.151.447Lake Geneva−0.060.631.001.672Lake Constance−0.061.020.951.871Lake Tahoe−0.460.830.280.822
Fig. 3
OSTIA LSWT analysis minus ARC-Lake observations for each lake, for JJA 2009, with absolute latitude (i.e. disregarding hemisphere) with (a) RMS and (b) mean difference. Each point represents a lake. A red triangle indicates the lake has an elevation over 2500 m, and a black dot equal to or below 2500 m. A blue square indicates the lake also has a surface area of greater than 3000 km2.
Fig. 4
OSTIA LSWT minus ARC-Lake observations for each lake, for JJA 2009, with isoperimetric quotient (a measure of how close to circular the lake is, or the regularity of the coastline, see text) with (a) RMS and (b) mean difference.
Fig. 5
Mean difference of (a) in situ observations minus OSTIA LSWT background and (b) AATSR observations minus OSTIA LSWT background. For each lake with available observations, for JJA 2009, with elevation. Note that 83% of in situ observations are located in the North American Great Lakes, whereas AATSR is spread globally.