| Popis: |
It is unusual inadequate precipitation that is the main factor leading to agriculture drought. The degree of precipitation deficit, the occurrence frequency and the duration are the main aspects for the quantitative calculation of drought hazard. China is a vast country with the complex and various types of landforms, and is affected by the significant monsoon climate, as result the farming activities are significant different over the country. In order to find out the comprehensively spatial differentiation of agricultural drought in a large area, this paper established a three-dimensional assessment model “I-P-L” for agriculture drought risk, where I,P,L means drought intensity, frequency, and length of duration respectively and drought is defined as the negative precipitation anomaly. daily data (from 1960 to 2009)of 535 meteorological stations in the recent 50 years was chosen for the drought risk calculation according to the water demand during the crop growing season, and the GIS technology was introduced into the risk mapping. The results showed that the Northwest, most of Inner Mongolia and Huang-Huai-Hai regions were of the high drought risk, while Tibet plateau and Sichuan Basin was lower. The agriculture hazard pattern has better tally with the drought centers got by many scholars, and can reflect the spatial differentiation of drought hazard. This paper can provide a scientific approach for the comprehensive hazards risk assessment and visual expression. This also can offer scientific proof to carry out risk evaluation and spatial, temporal pattern analysis on agricultural drought. |
