Abstract
The shifts in dry-wet climate regions are a natural response to climate change and have a profound impact on the regional agriculture and ecosystems. In this paper, we divided China into four dry-wet climate regions, i.e., arid, semi-arid, semi-humid, and humid regions, based on the humidity index (HI). A comparison of the two 30-year periods, i.e., 1960–1989 and 1990–2019, revealed that there was a shift in climate type in each dry-wet climate region, with six newly formed transitions, and the total area of the shifts to wetter conditions was more than two times larger than that of the shifts to drier conditions. Interestingly, the shifts to drier types were basically distributed in the monsoon region (east of 100∘ E) and especially concentrated in the North China Plain where agricultural development relies heavily on irrigation, which would increase the challenges in dealing with water shortage and food production security under a warming climate. The transitions to wetter types were mainly distributed in western China (west of 100∘ E), and most areas of the Junggar Basin have changed from arid to semi-arid region, which should benefit the local agricultural production and ecological environment to some extent. Based on a contribution analysis method, we further quantified the impacts of each climate factor on HI changes. Our results demonstrated that the dominant factor controlling HI changes in the six newly formed transition regions was P, followed by air temperature (Ta). In the non-transition zones of the arid and semi-arid regions, an increase in P dominated the increase of HI. However, in the non-transition zones of the semi-humid and humid region with a more humid background climate, the thermal factors (e.g., Ta, and net radiation (Rn)) contributed more than or equivalent to the contribution of P to HI change. These findings can provide scientific reference for water resources management and sustainable agricultural development in the context of climate change.
Highlights
Introduction published maps and institutional affilClimate change is characterized by a higher global average temperature with the ability to alter the global and regional atmospheric water cycle [1,2,3,4,5]
The meteorological observations for the period 1960–2019 were obtained from 635 meteorological stations of the China Meteorological Administration (CMA)
The hydroclimatic type of a certain area is determined jointly by the water input, i.e., The a certain is determined by the water input, i.e., P, and thehydroclimatic water output,type i.e., of potential evapotranspiration (PET) change jointly for a sustained period of time, P, and the water output, i.e., PET
Summary
Introduction published maps and institutional affilClimate change is characterized by a higher global average temperature with the ability to alter the global and regional atmospheric water cycle [1,2,3,4,5]. The simplest classification approach is to identify dry-wet regions based solely on annual precipitation [12,13,14]. Such approach merely considers the input of water and ignores the expenditure of water, cannot fully characterize the water budget of a specific region. Intensification of global warming has modified the potential evaporation which in turn influenced the surface moisture status [15,16,17].
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