Meso-Scale Comparison of Non-Sea-Effect and Sea-Effect Snowfalls, and Development of Prediction Algorithm for Megacity Istanbul Airports in Turkey

Abstract

This study aimed to determine the atmospheric conditions in which sea-effect snow (SES) and non-SES events occurred in a meso-scale structure. All snow events between 2009 and 2018 were found by examining the aviation reports at two international airports in Istanbul, Turkey. Then, threshold values and threshold intervals were presented for SES and non-SES events on the basis of many meteorological parameters (e.g., air temperature, dew point, relative humidity, heat fluxes, sea surface temperature (SST)). In addition, an algorithm was created for operational prediction of SES events at both airports. The most important parameter that distinguished SES events from NON-SES events was the temperature difference between sea surface (SS) and upper-atmosphere air parcel. Accordingly, sensible and latent heat fluxes had similarly higher values in SES events on average. Although the wind directions were mostly northerly in both event types, low wind shear in the layer between the SS and sub-inversion was prominent in SES events. For average snow depths, higher depths were measured in SES events than in non-SES events. In the same snow depth range, the heat fluxes were mostly high in SES events; on the other hand, the relative humidity values were lower.