Solar Radiation in the Northern Arabian Gulf – Evaluation of Remotely Sensed Data vs Observations from an Island Station

In spite of the economic importance of the Arabian Gulf (AG) there is a scarcity of published or publicly available surface meteorological observations. Such data, with adequate spatial and temporal coverage and resolution, are required for accurate estimation of surface heat-fluxes (e.g. to drive numerical ocean models). As part of an ongoing study, a full suite of surface meteorological parameters was collected from a station located on an island (Qaruh) off the Kuwaiti coast, between Jan-2013 and Apr-2014. One of the objectives of the study is to evaluate radiative fluxes in the AG from remotely sensed instruments since they provide the best available temporal and spatial coverage and resolution and thus may fill in for the scarcity of radiative flux observations. We report initial results from a comparison of shortwave solar radiation (SWR) flux observations to estimates of SWR from remotely sensed data. SWR, which is particularly intense in the AG (maximum measured value was 1065 W/m²), has important physical and ecological consequences, e.g. strong stable stratification of AG waters during much of the year. Observations were taken at 5-10 min intervals and averaged to 15 min. Estimates of SWR were obtained from the Spinning Enhanced Visible and Infrared Imager on board of Meteosat Second Generation with the Cloud Physical Properties algorithm developed by the Royal Netherlands Meteorological Institute. Nominal temporal resolution is 15 min with a spatial resolution 3x3 km², averaged here to 25x25 km². The SWR estimates from remote sensing closely followed those observed and a linear robust regression (6379 degrees of freedom) resulted in SWRremote = 1.02 x SWRobs + 19.46 Wm^-2, a significant correlation coefficient of 0.93, and a robust RMSE of 51.99 Wm^-2.