Mean Daily Variability of Energy Fluxes Above Alexandria Eastern Harbor

Abstract

Mean daily variability of latent heat (E), sensible heat (H), net long wave (Lwnet), net short wave, and net flux of surface heat balance were estimated from hourly sea surface water temperature (SST) and meteorological time series obtained for three months during summer season (2019) in Alexandria Eastern Harbor (AEH), Egypt. Latent and sensible heat were not in phase and had their maximum 181.12 W/m2 (5:00 PM), 16.5 W/m2 (5:00 AM) and minimum 103.64 W/m2 (8:00 AM), -12.14 W/m2 (3:00 PM), resulting in Bowen ration of -0.11 and 0.09, respectively. The loss of heat by evaporation therefore predominates than sensible heat utilized to warm surface atmosphere. The instability of the atmosphere was existing nearly most of the time period, rising exchange coefficients of sensible and latent heat flux by about 24.26% over estimated neutral values (from 1.15 × 10−3 to 1.43 × 10−3). Mean Lwnet changed from 165.63 at early morning to 173.52 W/m2 at late afternoon, point out its significant importance in the total balance of heat flux of eastern harbor surface. Latent heat flux and Lwnet were positive (energy losing from eastern harbor), throughout the day. The daily average of net energy budget (S) was 38.52 W/m2; daytime gain exceeded nighttime loss, with consequent heating the eastern harbor. Qualitatively, daily variations of net energy budget (S) were nearly consistent with time delay to the variability of sea surface temperature, indicating the predominant role of the heat budget of the surface layer in modulating surface temperatures of the Eastern Harbor. Keywords: heat flux, shortwave, long wave, latent heat, sensible heat, Eastern Harbor