Estimating High-Resolution Latent Heat Flux from Satellite (AVHRR-SST) and Reanalysis Data During Summer in the Tokar Gap, Central Red Sea
Abstract
This study aims to estimate latent heat flux (LHF) over the central Red Sea during the summer months (July and August) of 2000–2020, corresponding with the occurrence of the Tokar Gap (TG) wind jets. Sea surface temperature (SST) was derived from the SeaDAS-based multi-sensor ESA CCI/C3S satellite product (AVHRR-SST), and wind data were obtained from the scatterometer product. Both datasets were re-gridded to a uniform spatial resolution of 0.05°. The AVHRR-SST and scatterometer wind speed were compared with the corresponding ERA5 reanalysis fields. Because both the satellite-derived estimates and ERA5 are model-based products rather than independent in situ observations, this comparison constitutes an intercomparison between two approaches rather than a validation. The AVHRR-SST and scatterometer wind speed showed good agreement with ERA5 fields (correlation coefficients CC = 0.66 and 0.93, respectively). The spatial distribution of the estimated LHF reproduced the ERA5 LHF patterns but with relatively lower magnitudes. Time series analysis near the TG region showed that the estimated LHF underestimated ERA5 values, with a correlation coefficient of 0.77 and a root mean square error (RMSE) of 25.8 W/m2. The results represent an intercomparison between two model- and satellite-based approaches and are limited by the absence of independent in situ buoy observations for direct validation.