Dominant factor of dry‐wet change in China since 1960s

• Published in: International journal of climatology 2021-02, Vol.41 (2), p.1039-1055
• Main Authors: Xu, Jinqin, Wang, Dandan, Qiu, Xinfa, Zeng, Yan, Zhu, Xiaochen, Li, Mengxi, He, Yongjian, Shi, Guoping
• Format: Article
• Language: English
• Subjects: Arid regions; Arid zones; Climate; Climatic conditions; Differential equations; dominant factor; Drought; Drying; dry‐wet change; Evapotranspiration; Humidification; Hydroclimate; Potential evapotranspiration; precipitation
• ISSN: 0899-8418; 1097-0088
• DOI: 10.1002/joc.6728

The dry‐wet climate conditions of an area are mainly determined by the water input (e.g., precipitation, P) and output (e.g., potential evapotranspiration, PET). Based on three dry‐wet indices and the differential equation, this study designed a new attribution method to quantify the contributions of P and PET to the dry‐wet change, so as to determine the dominant factors of the dry‐wet change over whole China (CHINA) and various hydroclimate regions (i.e., arid region, AR; semi‐arid region, SAR; semi‐humid region, SHR; and humid region, HR) during 1960–2018 and six interdecadal periods. Results showed that the overall weak drying in CHINA was dominated by an increase in PET, while climate humidification in AR and HR was dominated by an increase in P, climate drying in SHR was dominated by the reduced P, and the weak drying in SAR was co‐dominated by P and PET during 1960–2018. The dominant factors of dry‐wet change over CHINA and each hydroclimate region varied in different decades. Briefly, climate humidification in CHINA and various hydroclimate regions was basically dominated by P in different decades, and the drying was mainly dominated by P in the 1960s–1980s, but the contribution of PET to climate drying began to become prominent after the 1980s. Besides, we found that P contributed more to dry‐wet change than PET on the station and regional scales, but the contribution of P to climate drying on a national scale was underestimated to some extent due to the regional offset effect of the increase/decrease in P during 1960–2018, as well as in the 1990s. These findings implied that the importance of research on the regional or local scale, and equal attention should be paid to the effects of P and PET changes in the future drought or dry‐wet change research. The dominant factors of dry‐wet change over whole China (CHINA) and each hydroclimate region varied in the period 1960–2018 and different decades. Briefly, climate humidification was basically dominated by P (precipitation), and the drying was mainly dominated by P in the 1960s–1980s, but the contribution of PET (potential evapotranspiration) to climate drying began to become prominent after the 1980s in CHINA and various hydroclimate regions.