Research On The Characteristics Of Climate Factors And Vegetation Variation In Typical Region Of Yellow River As Well As Their Response Relationship

Climate change influences water resources and vegetation, as same time it plays an key role in the economic society. Vegetation variation responds to climate and environmental sensitively. For recent decades, huge changes occurred on climate factors and vegetation in the worldwide, and so did in the Inner Mongolia reach of Yellow River which is regarded as a typical region of Yellow River, as well as the important economic development area and an ecological environment frail zone of Inner Mongolia. So that researching the climate factors, vegetation and their relations has important significance and reference value for water resource utilizing, eco-environment construction and economic society development.This thesis regards the Inner Mongolia Reach of Yellow River as study area which is the typical region of Yellow River, we analyzed the features of climate factors and the vegetation variation, as well as the response relationship between of them in a method of qualitative and quantitative.This research analyzed multi-set index of temperature and precipitation since 1951 to 2012, taken from 52 meteorological stations there and surrounding regions, and worked in various methods of regression analysis, compare mean, climatic tendency, Mann-Ken-dall test, Maximum Value Composite(MVC), the Dimidiate Pixel Model, Partial Correlations and so on, normalized difference vegetation index (NDVI) since 2000 to 2012. Finally, we obtained following conclusions,1. The greatest inter-annual variability of precipitation is found in the research areas for recent 62-years. The general tendency decreased slightly by-1.48mm/10a, what is a little different was in the period of 80s to 90s appeared a stepwise increase trend by a small margin of 9.2mm. The spatial distribution presented a pattern of more in the northeast area and less in the southwest area, in which area it presented the mean annual rate of deformation changed rapidly.2. The survey reflected an upward trend in the mean temperature of 0.283℃/10a, maximum air temperature of 0.235℃/10a and minimum air temperature of 0.59℃/10a, especially in ages of 1990s. The rapidly warming in winter with value of 0.539℃/10a forced the temperature increment primarily. The spatial distribution of temperature presented a pattern of high in the south area and low in the north area. The min.temperature of annual or season had mutations between 1977 and 1987 firstly, mean temperature followed it between 1978 and 1993, and the max. In the period of 1997 to 2007 after mutations, warming went into stagnant beginning in the spring and winter of 2002, and it happened in autumn of 2006 coming second, but it kept warming in summer. Most of above mutations of 1998 were later than the globe warming stagnancy.3. The variation of symmetries occurred among annual precipitation, annual mean temperature, mean max. temperature, mean min. temperature, except for the period of 1983 to 1999 presented an increasing trend. It appeared a good relationship between spring precipitation and above temperature, in comparison, it appeared asymmetric relation periodically between autumn precipitation and them.4.NDVI showed an increasing tendency during 2000 to 2012, which kept value of 0.38 on average. The tendency divided into two stages, as similar to inner-annual single apex. The vegetation coverage kept a rising trendy. Its growth rate on October was 0.0065/a which is the fastest in the whole period. The spatial distribution of vegetation presented a trend of variation from east to west. Better vegetation effected in the area, the lower the gradient of multi-annual rate.5. Under the conditions of the increasing cumulative precipitation of the month and vegetative period, the temperature increased in the month or last month, vegetation grew better, cumulative precipitation effected getting stronger. NDVI responded to the variations of precipitation or temperature or combined action of precipitation and temperature in different response ranges, such as vegetation were influenced both of water and temperature, when the precipitation, max. temperature, mean temperature, mix. temperature varying in a certain range of 8.77-106.40mm、13.85～26.04℃、20.50～32.37℃ 8.68-19.65℃, NDVI response to 0.29～0.39.