Analysis On The Climatic Conditions Of Forest Vegetation Growth In Liupanshan Natural Reserve

Great attention should be paid to the relationship of vegetation and meteorological factors when establishing forestry ecosystem in semi-dry areas of northwest China.This article studied the variation of characteristics of precipitation,temperature and humidity on interannual , seasonal and Intra-annual variations in Liupanshan Natural Reserve ,north area and south area mainly by using document comprehensive analyze,social surve in the past 38 yearsy,Comparison and Analyses and power spectrum method. And it also analyzed the relationship between NDVI and precipitation,temperature and humidity on interannual scale , seasonall scale and intra-annual scale by use of remote sensing data.Based on the research, the interannual variations in Liupanshan Natural Reserve in the past 38 years showed that: There was more precipitation In Liupanshan than in north and south area ,south area was substantially more than north area and it tended to decrease in last decade. The temperature in Liupanshan was lower than north and south area, south area was lower than north area. Temperature tended to increase after 1984 ,both peak and valley values , which also grew faster in recent 10 years,especially in north area. The humidity in Liupanshan was higher than north and south area ,south area was higher than north area. The humidity fell rapidly during a peroid of 20 years after 1989 ,especially in north area.The seasonal variations in Liupanshan Natural Reserve in the past 38 years indicated that :The precipitation showed a tendency to decreased in spring, particularly after 1989.It decreased markedly after 1998 in summer and increased after 1991 in autumn, especially after 2000.It also increased in winter after 1999.The temperature in all seasons was warming in different time, especialy in supring and winter ,which increased faster in recent ten years.The humidity in Liupanshan was higher than north and south area , south area was higher than north area except winter.The humidity also tended to decrease quickly in spring and summer,and increased in autumn.In winter,it increased slightly or remained the original humidity. Intra-annual variations in Liupanshan Natural Reserve in the past 38 years revealed that : The extreme precipitation period of a year was from July to september and it was under 20mm from February to November.The maximum precipitation showed a tendency to like September in recent 10 years, in other word, the precipitation increased obviously in September. The warmest month was July while the closest month was January. The temperature increased dramatically from November to Jully next year.The maximum humidity appeared from August to September, and the minimum humidity appeared from December to January before 90th, but the April tended to be the minimum month after 2000.The humidity declined markedly from march to June ,but increased from December to January in recent 10 years.The vegetation chang in Liupanshan Natural Reserve indicated that: The vegetation in Liupanshan Natural Reserve showed a tendency to become better, especially in Liupanshan and south area .The impacts of climate change in Liupanshan Natural Reserve on vegetation mainly revealed that : NDVI had a close relation with temperature and precipitation while vegetation was more sensitive to precipitation on monthly scale and annual scale and the vegetation change was the most stable on interannual scale.The vegetation tended to increase in summer and autumn on intra-annual.