Estimating the variance of the total surface heat flux over the Persian (Arabian) Gulf and the Gulf of Oman by using a statistical model.

摘要

The Persian (Arabian) Gulf and the Gulf of Oman have undergone few investigations of estimating the average and variance of the total surface heat flux. Since the total heat flux is a random variable, it is crucial to estimate its mean and its variance. Many authors have estimated the mean and the variance of the total heat flux (for example, see Wear et al. (1981), Ahmed and Sultan (1991), Sultan and Ahmed (1993), and Sultan and Ahmed (1994)). However, their estimations relied heavily on the bulk formulae and on the variance approximation technique described by Beers (1957).; The study area has been divided into two basins; the Persian Gulf is considered as one basin and the Gulf of Oman including the northern Arabian Sea is the second basin. The long-term annual mean values for short-wave radiation, sensible heat, latent heat, and long-wave back radiation fluxes of the study area between (15°N/30° N-49° E/63° E) are calculated and plotted. Each individual flux was computed using the bulk formulas and about 266,000 marine weather observations from COADS based upon 1° x 1° grid averages for the years (1960--1997). In addition, annual mean values of each meteorological variable and sea surface temperature are also plotted. Annual-monthly values of the incoming short-wave radiation, long-wave back radiation, sensible heat, and latent heat fluxes for 1960--1997 period in the Persian Gulf are 261, 60, 3, 116 W/m2, respectively. Over the Gulf of Oman and the northern Arabian Sea, the annual-monthly values of upward heat fluxes due to short-wave radiation, long-wave back radiation, sensible heat, and latent heat are 255, 56, 1, 144 W/m2, respectively. The annual averages of the total heat flux for both basins are +82 and +54 W/m 2, respectively.; An error analysis is used based on a regression model and the Taylor series approximation techniques and the standard deviations of the total heat flux for both basins are computed to be +/-11 and +/-10 W/m 2, respectively. The percentage contributions of sea surface temperature Ts minus air temperature Ta (Ts - T a), the saturation specific humidity of air at sea surface temperature qs minus specific humidity of air qa (qs - qa), cloud, and wind to the estimated variance of the Persian Gulf basin are found to be 2, 23, 10, 65, respectively. Based on the data results for the Gulf of Oman and the northern Arabian Sea, the contribution of the (qs - qa) to the variance is 67%, whereas the wind, (Ts - Ta) and, cloud are (26%, 2% and 5%) respectively. (Abstract shortened by UMI.)