Changes in dry spell durations associated with temperature warming and precipitation variations over the Indo-China Peninsula

Abstract

Dry spells have negative implications for water security and agriculture. Climate changes associated with increasing temperature and precipitation variations lead to changes in dry spell durations. The variability of the dry spell duration during the rainy season (May–October) over the Indo-China Peninsula (ICP) was analyzed, and the contributions of the temperature and precipitation changes with respect to the trend in the total duration of dry spells (TDDS) were quantified using linear regression methods. The results indicate increasing trend in the with a rate of 0.9 days/10 year over the entire ICP. Nevertheless, the trends presented great spatial variability, and 37.4% and 10.7% of the peninsula presented significant increasing and decreasing trends at the 95% confidence level, respectively. Climate warming has led to a considerable elongation of the dry spells during the rainy season at a rate of 5.3 days/°C, and areas with precipitation less than 1000 mm and higher than 2000 mm generally show faster increases. The change rates are clearly asymmetrically distributed with the dry spell duration, with hotter rainy seasons witnessing more frequent long-duration dry spells. On the other hand, considerable increasing precipitation shortens the dry spells, while decreasing precipitation facilitates the dry spell extension caused by rising temperatures. As the climate continues to warm, hotter rainy seasons will favor more frequent and prolonged dry spells, which will further exacerbate drought and heat waves over the ICP. These research results are expected to provide reference for agricultural activities, water resources management, and disaster prevention over the ICP.