Reassessment of heat budget in the Mediterranean Seaand uncertainty in the probability distributions of heat fluxes

In a semi-enclosed sea basin, like in the Mediterranean, determining the heat flux components of the heat budget is crucial for better understanding of the water budget and the regional climate. Due to its relatively small sea basin and existence of many islands, it’s always a complex and uncertain to settle with an accurate net heat balance. The variation in the net heat budget is referred as a heat budget “closure” problem, which has referred by many authors for the Mediterranean Sea. The value of net heat flux under this closure hypothesis should be negative, but there is a considerable range of variation for net heat budget in published literatures. In that context, we have computed the heat fluxes for in the Mediterranean Sea using a higher resolution atmospheric model analysis dataset (ECMWF) along with heat fluxes using a lower resolution dataset (ERA5) to compare. The computation of heat fluxes using high resolution ECMWF analysis dataset is a newer one for the Mediterranean Sea. The resulted long-term climatology of heat flux components (between ECMWF & ERA5) has shown a close agreement except a variation is observed in the Long Wave (LW) flux which matches a similar finding from Marullo et al. (2020). In addition to the net heat budget, this study aims to provide a newer aspect with the analysis of probability distributions of air-sea fluxes and uncertainty in those distributions. We have investigated the probability distributions of heat fluxes on the base of computed air-sea fluxes time series. We have analysed the probability distributions of air-sea fluxes using atmospheric analysis and reanalysis datasets and fitted with three parameters Probability Density Function (PDF). Then, we have evaluated the applied theoretical PDF fits with observed heat fluxes that have indicated areas with uncertainty through our statistical modelling approach for the turbulent heat flux distributions. The statistical analysis of air-sea fluxes is not a usual one for the Mediterranean Sea but an important one to obtain the statistical inference of air-sea flux distributions in relation to the probable uncertainty arises in the ocean forecasts.