| Agricultural climate resources problems are the fundamental problems ofclimate resources, each exception climate change has left traces of the influence onagricultural production. Agricultural climate resources are usually summarized asheat, light, water resources, and the number of these resources, distributioncharacteristics and cooperate with each other, will eventually form a variety ofagricultural climate resource type. The situation of agricultural climate resource isone of the key factors of agricultural production and sustainable development, it willdirectly impact the process of agricultural production. In general, the agriculturalclimate resource is by its own size, with the change of time and resources fromdifferent magnitude combination type to represent the quality of the pros and cons;various resources different magnitude control area as well as the its combinationtype control area to represent the amount.The Huanghe River Watershed has play a decisive role on Chinese agricultureand the whole national economy development. Therefore, in this paper,meteorological data during1960-2010of70stations in the Huanghe RiverWatershed from China Meteorological Administration(CAM) were used. After dataprocessing, Firstly, we applied climate tendency rate method, moving averagemethod, Mann-Kell test and other mathematical method to analyze thetemporal-spatial variation of agricultural climate resource(≥10℃accumulatedtemperature, sunshine and water resources) of the Huanghe River Watershed and thebasin in different reaches from1960to2010; Secondly, based on the former research,discusses the differences of agricultural climate resources in the Huanghe RiverWatershed in different dry farming areas, and select typical site analysis the changelaw of agricultural climate resources in the Huanghe River Watershed in differentdry farming areas; Once again, application of≥10℃accumulated temperature andthe same period precipitation data to calculating the growth period of aridity index,and to analyze the temporal-spatial variation of aridity index; Finally, based on R/Sanalysis prediction the future trend of agricultural climate resources in the HuangheRiver Watershed.In conclusion, some important results are obtained as follows: (1)≥10℃active accumulated temperature showed that the distribution in theHuanghe River Watershed has obviously regional difference, vertical changeobviously. And it is showed that the distribution of≥10℃accumulated temperaturefor many years an average varies from2546.92℃to3104.37℃. Regionaldistribution of10℃activity accumulated temperature shows obvious North-Southand East-West differences; Inter-annual variability is concerned, since1960a, the10℃activity accumulated temperature has increased trend. Among them, the10℃accumulated temperature increasing in the Huanghe River Watershed upstream,middle and downstream, and the average growth rate were60.0℃/10a,58.9℃/10aand45.9℃/10a, thus it can be seen, upstream activity accumulated temperature lagerinter-annual variability. Different dry type accumulated temperature showed asignificant rising trend, climate tendency rate performance: Ⅰ area>Ⅲ area>Ⅳarea>Ⅱ area>Ⅴ area, arid area (Ⅰ area) of the most obvious increasing trend,heating rate is74.75℃/10a, and larger inter-annual variability.(2) In recent51years, the sunshine hours showed not obvious decreasing trend inthe Huanghe River Watershed, decreasing rate of1.88h/10a, the results are consistendwith the national sunshine hours study has been a downward trend in1956~2002a.The annual sunshine duration was roughly zonal distribution(That is high in the Northand South low distribution form); Average many years sunshine hours in between92.09~1630.06h, average sunshine hours most distribution area in Hetao plain,northern Ningxia and downstream scattered areas, sunshine hours average many yearvalue between1455~1630h, of which the Ji，nan showed most of the sunshine hours,average annual sunshine hours for1630.06h, while the least value appears in thesource region of the Yellow River; From climate change tendency to see, decrease thenumber of sunshine hours mainly concentrated in the basin of Eastern Shanxi andHenan, Shandong, the North China plain area, followed by the Xining of QinghaiLake East, and as well as Henan, Yinchuan, Lanzhou, Xingxian and other areas;sunshine duration increased mainly in the source region of the Huanghe RiverWatershed. Sunshine hours of inter-annual variation in different dry farming areasshow significant regional differences, located in northern arid and half arid andsemi-arid area near51a to sunshine duration increased, the increase in arid area is the most obvious; southeastern semi-humid area liable to drought and wetness area ofsunshine hours when the number showed decreasing trend.(3) Through analyzing the precipitation changes of the Huanghe River Watershedin the past51years, it is showed that the distribution of rainfall for many years anaverage varies from46.25mm to798.94mm. The area distribution of rainfall in theHuanghe River Watershed has obviously regional difference, which is influenced notonly by the weather system but also by the geographical environment such astopography, etc. The main distribution trend is that there is more in the Southeasternand less in the Northwestern, precipitation from the Southeast to the Northwestdecline. From the overall to see, precipitation is the development trend of decreasingyear by year. There is differences of precipitation distribution on different reaches ofthe Huanghe River Watershed, the upper reaches of the Huanghe River averageprecipitation since1960a began to overall change range is not big, belongs to thenormal fluctuation and risen slightly, the increase of0.77mm/10a; The Huanghe Rivermiddle reaches climate condition to drought is given priority to, the precipitationshow at7.72mm/10a rate decrease trend; The change trend of downstream andupstream is consistent of precipitation and rise by3.33mm/10a, increase trend obvious,precipitation appeared roughly nine times more rain, less rain cycle. From the nearly51a average precipitation change perspective to see of different dry farming areas inthe Huanghe River Watershed, precipitation showed not obvious decreasing trend. Inaddition to humid area (Ⅴarea) precipitation showed weak increase trend (increaserate for1.61mm/10a), the other four areas showed decreasing trend, in thesemi-humid area liable to drought (Ⅳ) for maximum reduction of precipitation,average every10a reduce9.28mm, semi-arid region (Ⅲ) and half dry arid semiaridareas (II) times, respectively-2.63mm/10a,-2.64mm/10a, arid area minimum,-1.18mm/10a.(4) Since the1960s, the whole basin of aridity index were generally stableincrease trend, namely gradually toward the drought become the direction ofevolution. Aridity index change trend on the upper-middle reaches and the whole riverbasin are basically the same of the Huanghe River Watershed, but the lower HuangheRiver Watershed of dry degree performance to reduce trend. Nearly51years climate has a dry year by year trend of the middle in the Huanghe River Watershed;Downstream aridity index in addition to60s and80s higher than average for manyyears the average, and the other s are below average for many years, especially after80s aridity index for the performance of the year by year and the trend of decrease.The Yellow River phase aridity index of spatial variation in zonal distribution, aridityindex space distribution performance is: from the south to the north with the increaseof latitude aridity index also gradually become larger, the climate became dry.(5) The results of R/S analysis: different regional active accumulated temperatureand sunshine time Hurst index of persistent mild although have change ups and downs,but the Hurst index always greater than0.5, which, on the one hand the Yellow Riverreach that different areas and different dry activities accumulated temperature,sunshine time change trend maintained a long-term correlation characteristics. Andrainfall, aridity index large sample sequence of Hurst index appear less than or equalto0.5change turning point that future rainfall, aridity index on the randomness of thegreat. |
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