Spatial and temporal characteristics of rice production climatic resources in main growing regions of China

The climate resources during rice-growing periods in main growing regions of China are highly uncertain because of its vast area and marked variation. The daily meteorological data during the years from 1961 to 1970 (1960s) and 1996 to 2005 (2000s) of 333 weather stations in main rice growing regions of China were processed to generate the gridded daily meteorological surface data using ANUSPLIN and ARCGIS. The spatial and temporal distribution characteristics of the climate resources for the rice production, including total sunshine hours, total growing degree days above 10℃, average difference of diurnal air temperature, total precipitation, total rainfall days and average daily precipitation during rice-growing periods between two decades (1960s and 2000s) were calculated and analyzed based on the grid cell. As compared with 1960s, the total sunshine hours in rice-growing periods of 2000s decreased by 11.93%, and the decreasing rates of total sunshine hours in the Northeast and Southwest China were lower than those in the Middle and South China. From 1960s to 2000s, the total growing degree days above 10℃ increased by 9.40%, and the increasing rates of total growing degree days above 10℃ in the Northeast and Southwest China were faster than those in the Middle and South China. However, in part areas of the Middle and South China, the total growing degree days above 10℃ during rice-growing periods decreased. The average differences of diurnal air temperature during rice-growing periods of 2000s decreased by 4.86% as compared with 1960s, while increased in part areas of the Middle and South China. The decreasing rates of average difference of diurnal air temperature in the Northeast and Southwest China were higher than those in the Middle and South China. Compared with 1960s, total precipitation during rice-growing periods in 2000s increased by 1.59% and average daily precipitation increased by 3.22%. The spatial distribution of the change rate of average daily precipitation was similar to that of total precipitation, the total precipitation and average daily precipitation decreased in Ningxia province and the Northeast China, while increased in the Middle and South China. Compared with 1960s, the total rainfall days during rice-growing periods of 2000s decreased by 1.60%, and the decreasing rates of total rainfall days in the Northeast and Middle China were lower than that in the South China. These results can provide the technical support for further analysis of yield increasing potential and yield increasing method of rice in China.