Abstract
Climate change is likely to have a remarkable impact on the water cycle of crop growth, crop water requirement (CWR), and consequently crop irrigation water requirement (CIWR). In this study, the CIWR of spring and winter wheat from 2001 to 2030 in the Yellow River basin (YRB) was assessed by crop irrigation water model under the climate change scenarios SRES A2 and B2 of general circulation model (GCM) HADCM3. The climate variables obtained from 265 climate stations from 1961 to 1990 in the YRB domain were used to create climate grids in 0 .1-degree to provide high-resolution spatial information . The climate variables of HADCM3 output in 2.5-degree latitude and 3.75-degree longitude were downscaled to 0 .1-degree grids by a simple statistical method. The method can integrate the local climate heterogeneity of the YRB with the past climate records from the 265 climate stations, and future climate changes from the output of GCM HADCM3. Following the crop irrigation model of FAO, the monthly and yearly reference evapotranspiration, CWR and CIWR from 2001 to 2030 in the YRB were assessed . Based on the downscaled climate scenarios, there would be temperature increase and precipitation decrease in the YRB in the coming three decades. Accordingly, the CWR, and CIWR of both spring and winter wheat would increase. The climate change under climate scenario A2 is likely to have a larger impact on CWR and CIWR than scenario B2.
