The potential role of land cover on secular changes of the hydroclimate of Peninsular Florida

Abstract

The seasonal cycle of Peninsular Florida rainfall is a robust feature that has monsoon like seasonality. We objectively define the onset, demise, and length of the wet seasons over the time period of 1948–2006 in Peninsular Florida based on daily rainfall from the Climate Prediction Center of the National Centers for Environmental Prediction. This definition defines onset (demise) of the wet season of Peninsular Florida as the first day the daily accumulated precipitation anomaly reaches a minimum (maximum) for the year at a given grid point. A discernible linear trend of later onset, earlier demise, and a resulting shorter length of the wet season in urban areas relative to the rural areas is observed. The wet season accumulation of rainfall, however, does not reveal a proportional change in the linear trend implying a perceptible contrast of comparatively higher (lower) linear trend of the daily rain rate of the wet season over urban (rural) areas of Peninsular Florida.

Summary

Peninsular Florida is characterized by a distinct rainy season that begins in late Spring or early Summer and ends in late Summer or early Fall. This observational study indicates a pattern of increasing and decreasing trends in the length of the wet season in rural and urban regions of peninsular Florida, respectively. However, the seasonal accumulation of wet season rainfall does not display any such pattern with land-surface type. This implies that daily rain rates of the wet season are increasing in urban regions while they are decreasing in the rural regions of peninsular Florida. The evidence presented in the study points to the potential influence of land-surface variations on the trends of the changing seasonality of wet season of peninsular Florida.