Under The Background Of Climate Change, The Research Of The Disaster Loss Assessment Technology On Corn Drought In Northwest

In recent decades, by the impact of global warming, agriculturemeteorological disaster occurred frequently in our country, drought had become amajor factor that can affect maize production in Northwest. Under the background ofclimate change, a study of assessment technical was carried out about the impact ofdrought on food output, its had a very important practical significance for agriculturedisaster prevention, reduction and food security, and its can prevent agriculturemeteorological disaster, avoid disadvantages, improve the ability of disasterprevention, mitigation and disaster, ensure steadily increasing of agriculturalproduction, promote the sustainable development of agriculture, at the same time,drought distribution regularity was also a basis of the adjustment on cropping system,crop distribution, etc.Firstly, change characteristics and trends of precipitation in the NorthwestTerritories, as well as the impact of drought on agriculture and corn yield wereanalyzed. Based on these, Secondly, taking the spring corn in Gansu province as anexample, the relative meteorological yield was calculated, a quantitative assessmentindicator-DI index was constructed, which took CI index、the ratio of precipitationand water demand on developmental stage as its parameters by using the data of dailyprecipitation0f4-9months from1985to2007、CI index、corn yield and the waterdemand of developmental stage. Furthermore, using comparative analysis method,positive and negative combination methods, the feasibility of indicator and indicatorparameters was fully verified and empirical analyzed, growing season and majordevelopmental stage DI index model were established, drought accumulated DI indexwas inversed, drought index level was divided, drought disaster numericalquantitative analysis was carried out, the temporal and spatial variation of corndrought were studied in Northwest by Arcgis technology, disaster damage assessmenttechnology of drought to corn was proposed. The results showed that：(1)Drought index was simple, clear, in which the impact of the medium-longterm precipitation, the growing season, the main growth period precipitation and the factor of crop water demand on main growth period were covered, not only containeda meteorologist significance, but also increased the biological significance, obtainedresults of assessment were more accurate, it was feasible, practical, and innovative asthe assessment indicator of corn drought disaster and losses in Northwest.(2)From the annual variation of DI index in the growing season, the fluctuationsand values of Xifeng and Wudu were the largest, Yuzhong, followed by them, thefluctuations and values of Jingyuan and Yongchang were the smallest.(3)From the annual variation of DI index in major developmental stages, thefluctuations and values of sowing-seeding and silking-maturity were the largest, thefluctuations and values of seeding-jointing and jointing-silking were the smallest.(4)From the annual variation of DI index in different developmental stages,developmental stages: the fluctuations and values of sowing-seeding andsilking-maturity were the largest, the fluctuations and values of seeding-jointing andjointing-silking were the smallest; representative stations: the values of Xifeng andWudu were the largest, Yuzhong, followed by them, the values of Jingyuan andYongchang were the smallest.(5)From drought frequency distribution of growing season and maindevelopmental stages, the southern and eastern region were prone to occur middledrought, the central region was prone to occur middle drought, the northern was proneto occur extreme drought, which is much higher than the eastern and southern.