Long-term Precipitation Trend to Identify Drought and Flood Risk

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Long-term Precipitation Trend to Identify Drought and Flood Risk

Discussion: The incidence of drought/flash drought and flash flooding events has increased. To monitor where these episodes are most likely to occur knowledge of longer-term precipitation patterns is helpful. The International Research Institute for Climate and Society has identified regional dry and wet zones based on a ranking of monthly precipitation over the past 3 months (Fig. 1). Dark brown areas are where monthly precipitation rankings have been in the dry tercile for the past 3 months. These regions are either in drought (Australia) or could easily slip into drought given a dry (or hot) short-term climate (Brazil). Conversely, very wet zones susceptible to flash flooding if additional heavy precipitation occurs include East Africa and France.

Fig. 1: The monthly persistence of precipitation (based on the past 3 months) analysis by the International Research Institute for Climate and Society.