Trends of Chinese dry-wet condition based on wetness index

Predicting the temporal and spatial change of Chinaese dry-wet condition in the future can provide important theoretical support for developing the national response strategy on climate change, and adjusting the distribution of agricultural production layout. Based on the daily data of A2 climate scenario (2011-2050) and baseline climate condition (1961-1990) from the regional climate model PRECIS with resolution of 50 km×50 km, reference crop evapotranspiration and the wetness index were both calculated and analyzed according to Penman-Monteith equation recommended by FAO. In terms of grades of wetness index from Chinese Climate Classification Criterion, China is classified into severe arid, arid, semi-arid, semi-humid and humid zones, respectively. The possible temporal-spatial changes of dry-wet condition over the country from 2011 to 2050 were analyzed from an agricultural view. The results showed that: the amount of precipitation and reference crop evapotranspiration in the most regions would increase from 2011 to 2050 compared with the baseline climate conditions from 1961 to 1990. However, the inter-regional difference was significant; In the next 40 years, Chinaese climate showed a warming and drying trend in general; The area’s reducing trend in the arid and extreme arid region and the expanding trend in the semi-arid region during 2011 to 2050 would be obvious compared with the baseline climatic conditions. Climate would turn wetter in the northwest part of Xinjiang and the areas along the Great Wall and Inner Mongolia; while part of the semi-arid region e.g. southeast Loess Plateau and the central part of Qinghai-Tibet Plateau would become drier.