| With the research of the climate change deeply, more attention have been attracted to theimpact of climate change by the world, and the research about the impact of climate changeon agriculture water demand is the current hotspot. As a large agriculture country, agriculturewater occupies more than60%in the water structure in our country, and the Huang-Huai-Haidistrict is an important grain production base, where agriculture water demand impacted byclimate change is significant. Therefore, carried out the research, which the impact of climatechange on agriculture water demand, has important scientific significance and practical valueto our country’s agriculture and social economic sustainable development and sustainableutilization of water resources in Huang-Huai-Hai district. Based on the systematic summaryto the impact of climate change on water resources system, the main meteorological elementsare analyzed in Huang-Huai-Hai district in this paper, and the impact of climate change onagriculture water demand is discussed in detail. The main research contents and results in thispaper are as follows:(1)Variation characteristics of temperature and rainfall, which at23representative sitesin the study area, are analyzed in annual scale and seasonal scale based on the Mann-Kendalltrend analysis method, also the year of mutation are tested. The result showed: In annual scale,there are significant warming trend in the Haihe river, Yellow river and Huaihe river district,and the year of mutation is concentrate in the1990s about. The spatial distribution of averageannual temperature showed there are significant difference in average annual temperature inthe study area, and the variation trend of rainfall is not obvious, even it has a faint decreasetrend, and the average annual rainfall is zonal distribution in spatial. In seasonal scale, thereare warming trend obviously in the spring in the Huaihe river district, and the warming trendis bigger in winter in the Haihe river and Huanghe river district, and the area that warmingtrend is most significant is concentratein the Huang-Huai-Hai plain in each season; Thevariation trend of rainfall is not significant in each season, and the fluctuation of average annual rainfall is most obvious in season in Huaihe river district, and there are smallfluctuation in the Haihe river district and Huanghe river district, the spatial distribution ofaverage annual rainfall in season showed the spatial distribution of rainfall is differentobviously in spring and summer, and it is little difference in autumn and winter, and the lessrainfall area is concentrate in the northwestern of the Yellow river in all the four season, andthe rainfall in the upper reach of the Huaihe river district is more.(2)Adopted Penman-Monteith formula calculates the reference crop evapotranspiration,and based on the sensitivity analysis theory analyzes the sensitivity of reference cropevapotranspiration to the temperature, wind speed, sunshine hours and relative humidity. Theresult showsaverage annual ET roughly stepwise increase from west to east in space, thelargest area of ET are mainly distributed in the north china plain, especially in the borderregion of Yellow river district, Huaihe river district and Haihe river district; The sensitivityanalysis result showedtemperature, wind speed and sunshine hours is positive influence forET, and the relative humidity is negative influence, what’s more, the Huaihe river district andHaihe river district that affected by the temperature are largest, and various meteorologicalelements are little difference to the ET in the Huanghe river district, and the spatialdistribution of meteorological elements coefficient show various meteorological elementssensitive coefficient close to radial distribution in space.(3)Setted up temperature change three kinds of different scenarios, then calculated andanalyzed the influence of the temperature change for the ET and the crop water demand ofwheat and corn. Average annual water demand contour under the temperature without changeshowed average annual water demand of wheat is step-wise distribution in the study area, andaverage annual water demand of corn is no obvious regularity. When the temperature increase1～3℃, ET vary linearly in each site, average annual water demand of wheat respectivelyincrease16.56mm～58.34mm,32.99mm～115.38mm,49.1mm～174.41mm, and theincrement of corn average annual water demand are15.17mm～47.12mm，30.51mm～93.61mm，44.33mm～139.27mm.(4)Calculated and analyzed the impact of climate change on wheat and corn irrigationwater demand under the temperature and rainfall change different scenario combinations.Average irrigation water demand of wheat is391.42mm～519.18mm during the growthperiod under the rainfall no change, and the corn is302.48mm～384.76mm. Under therainfall change different scenario, the correlation which the corn irrigation water demand withthe effective rainfall in the growth period is less than wheat, and the reducing irrigation waterdemand which caused by rainfall increase10percent can’t make up the increment ofirrigation water demand caused by temperature increase1℃,and the response of the corn issmaller than wheat for the temperature and rainfall. The variation diagram of crop irrigation water demand under the temperature and rainfall change different scenario combinationsshow it will be make the crop irrigation water demand to gradually increase when thecontours are higher than0, otherwise, the crop irrigation will be gradually decrease when thecontours are lower than0. |
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