IMPROVEMENT OF REGIONAL PREDICTION OF SEA FOG ON GUANGDONG COASTLAND USING THE FACTOR OF TEMPERATURE DIFFERENCE IN THE NEAR-SURFACE LAYER

The relationship between the factor of temperature difference of the near-surface layer (T-1 (000 hpa)-T-2 m) and sea fog is analyzed using the NCEP reanalysis with a horizontal resolution of 1 degrees x 1 degrees (2000 to 2011) and the station observations (2010 to 2011). The element is treated as the prediction variable factor in the GRAPES model and used to improve the regional prediction of sea fog on Guangdong coastland. (1) The relationship between this factor and the occurrence of sea fog is explicit: When the sea fog happens, the value of this factor is always large in some specific periods, and the negative value of this factor decreases significantly or turns positive, suggesting the enhancement of warm and moist advection of air flow near the surface, which favors the development of sea fog. (2) The transportation of warm and moist advection over Guangdong coastland is featured by some stages and the jumping among these states. It also gets stronger over time. Meanwhile, the northward propagation of warm and moist advection is quite consistent with the northward advancing of sea fog from south to north along the coastland of China. (3) The GRAPES model can well simulate and realize the factor of near-surface temperature difference. Besides, the accuracy of regional prediction of marine fog, the relevant threat score and Heidke skill score are all improved when the factor is involved.