Trends Of Extreme Daily Precipitation And Temperature And The Correlation With NDVI In Inner Mongolia

The report of IPCC show that the global temperature has been rising in the past100years. Inaddition, it has the trend of speeding up. Because of the frequent global high temperature、drought andflood，the global climate change problem become the greatest concern all over the world.The questionbetween the ecological environment and the global climate change is becoming the important researchaspect of science.However, the extreme climate is the important research aspect in climate change study.Inner Mongolia is located in the heart of the Eurasian land, north of China’s territory.It is an important partof the Mongolian plateau, one of China’s four big pastures. And its unique ecological and environmentalconditions make it more vulnerable to the effects of climate change. The article use the weather record of46weather stations in Inner Mongolia and the GIMMS NDVI date, analyzing the tendency of extremeclimate and NDVI in Inner Mongolia.Computing the daily value of46national meteorological observation stations in Inner Mongolia usingRclimDex（1.0）,we get19extreme climate indices. On this basis, we analyze the trend of extreme climateevents over the past50years. Indices of extreme climatic events in the whole study region have a similarchanging trend. There was a upward trend in indices of extremely high climatic events such as Summerdays, Growing season Length,Warm days, Warm nights, Warm spell duration indicator,but a downwardtrend in indices of extremely high climatic events such as Frost days, Cool days, Cool nights, Cold spellduration indicator. And this shows that respectively an upward trend and a downward trend in extremelyhigh climatic events and extremely high climatic events in the whole region in Inner Mongolia. In the past50years, there was an obvious upward trend in temperature in this region. We also found in the study thatthe changing range of TN10P, TN90P was larger than that of TX10P, TX90P, which shows that the heatingup at night was larger than that in the day in Inner Mongolia. However, extreme precipitation index dosen’thave the consistent tendency compared to the temperature index. However, as a whole, extremeprecipitation is slowly falling, and extreme dry events is increasing slowly, and this situation is happeningto some areas including eastern farming areas、grassland areas、forest areas.Through the analysis of NDVI in Inner Mongolia in the past25years, the result demonstrate: From all overthe region, NDVI is rising slowly, and in the different years NDVI is also different, and the reason is thatthe weather factor is differ of the year from the other year; the time of the latter period(1995-2006) is longer when NDVI get to the peak than the ahead period(1982-1993); Through the comparison of thedifferent growth period, NDVI is decreasing when the vegetation resume growth(April, May), but NDVI isincreasing when the growth get the peak(July, August).We get the correlation of NDVI and extreme climate index, and the result indicate below: The meanNDVI and the extreme precipitation index all over the region have the medium correlation, and thecorrelation of the NDVI and the extreme temperature index is smaller. Generally speaking, comparing withthe research on NDVI and the general weather factors, the correlation of this article is smaller, and thereason maybe is that the two targets of this research is not corresponding.