The response of agricultural drought to meteorological drought modulated by air temperature

Abstract

Due to climate change, there is an increasing occurrence of combined extreme events. The interaction between agricultural drought and meteorological drought may be significantly influenced by the temperature conditions. However, the specific process and the extent of air temperature’s impact on the dynamic remain unknown. To this end, the present study develops a copula-based coupling model to integrate agricultural drought, meteorological drought, and temperature state. This model is designed to investigate how temperature affects the agricultural drought response to meteorological drought, and to determine the transition threshold of temperature state on agricultural drought responding to meteorological drought from inhibition to promotion under diverse drought conditions. Furthermore, the proposed model is used to explore the spatial distribution characteristics of sensitivity and temperature thresholds in summer over mainland China. Finally, the geographical detector model is employed to investigate the primary factors influencing the spatial distribution of sensitivity and temperature thresholds. Results indicated that: (1) high temperatures have intensified the response of agricultural drought to meteorological drought in over 88% of mainland China, while in the Qinghai-Tibet Plateau region of the Inland River basin, this response is mitigated by glacier meltwater resulting from high temperatures; (2) the thresholds are lower in the Southeast River basin, the lower reaches of the Yangtze River, the Pearl River basin, the southern Songliao River basin and the Haihe River basin, but higher in the Yellow River basin, the western Yangtze River basin, the southern Inland River basin and Yunnan Province; and (3) the land-atmosphere coupling is crucial in determining both sensitivity and threshold levels.