Continuous detection and characterization of the Sea Breeze in clear sky conditions using Meteosat Second Generation

Abstract

The sea breeze (SB) is a thermally induced boundary layer phenomenon that occurs at coastal locations throughout the world. Previous satellite remote sensing studies used low-level clouds formed over the sea-breeze convergence zones to identify the SB. In this study continuous thermal infrared data from a geostationary satellite (Meteosat Second Generation) and concurrent field measurements were used to detect and characterize the SB in clear sky conditions during the summer. Surface data (wind speed and direction) from 11 sites over Israel for ten summer days in July 2010 for three different synoptic circulation categories were selected. In order to assess the impact of the synoptic induced flow on the SB, we looked for the best agreement between surface and satellite SB timing. An independent classification of synoptic categories performed for the ten summer days revealed two distinct patterns of the SB. During weak horizontal pressure gradient (Weak Persian Trough and High to the West), which enables full development of the SB, the timing of the SB from satellite and field measurements were well correlated (R2 = 0.75), as compared to unfavorable atmospheric conditions (Deep Persian Trough) yielding lower value (R2 = 0.5). The SB was identified by surface measurements in an earlier time of the day, with respect to the satellite column integrated measurements. Visualizing timing of the SB retrieved from satellite data enabled distinction of SB behavior under different synoptic categories. Over desert regions the strong thermal contrast enables detection of the SB even under suppressing synoptic conditions (Deep Persian Trough). This method enables detection and timing of the SB over desert regions where clouds and field measurements are scarce, and is applicable worldwide.