Ningxia Climate Change And Its Effects On Vegetation Cover

It's not exactly the same that different climate belts'responses to global climate change. Ningxia belongs to mid-temperate semiarid continental climate with few rains, strong wind and plenty of sands, as well as frequent drought. Arid climate and climate change are the key factors causing the change of vegetation distribution and ecological environment in Ningxia. Therefore, to get deep into the basic facts of Ningxia's climate change under the context of global warming, and to unclose the evolution rule of Ningxia's vegetation distribution under the circumstance of climate change, are of great importance to Ningxia's social and economic development, ecological environment development and impact evaluation and other aspects. Based on weather data of all meteorological stations in Ningxia over the past 40 years and the NDVI data from 1981-2004, climate change, vegetation change as well as climate change's impact upon vegetation change in Ningxia have been studied, which shows:1. Ningxia's annual average temperature shows noticeable characteristics of inter-decadal change. Around 1986, a climate jump took place, and after the climate jump, annual average temperature increase 1.0℃. The season with most obvious temperature increase is winter, and the area with most obvious temperature increase extent is the middle arid belt in Ningxia. The amount of precipitation does not show obvious characteristics of inter-decadal change. A climate jump took place in 1978 to the amount of precipitation in autumn, and after the climate jump, the amount of precipitation decreases nearly 33%.2. Over the past 40 years, the small-sized pan evaporation in Ningxia shows a noticeable downtrend. The season with most obvious downtrend is summer, while the area with most obvious downtrend is the southern mountainous area in Ningxia. Over the past 40 years, the occurrence of strong wind in Ningxia shows a slight downtrend.3. From 1981 to 2004, the annual vegetation coverage of Mont Helan and the east foot of Mont Helan in Ningxia were decreasing, while that of the middle arid belt and southern mountainous area was increasing. In Mont Helan, vegetation coverage decreases in summer but increases in spring, autumn and winter. In the east foot of Mont Helan, vegetation coverage decreases in summer and winter but increases in spring and autumn. However, since the 21st century, the vegetation coverage of all four seasons is decreasing, which shows that the desertification of the east foot of Mont Helan is getting more serious. In the middle arid belt, the vegetation coverage of all four seasons is increasing; and the vegetation situation of southern mountainous area is obviously getting better.4. The correlation between precipitation in spring and summer and the vegetation coverage in spring, summer and autumn in Ningxia is comparatively obvious. When the precipitation increases, the vegetation coverage increases too, especially in the middle arid belt, the precipitation amount is noticeably related to vegetation coverage. The precipitation amount in May constitutes the strongest impact upon the vegetation coverage of the same month and the following 1-2 months. The correlation between temperature and vegetation coverage of different seasons is not so clear, which shows that in the arid and semi-arid area of Ningxia, the amount of precipitation is the key factor affecting the growth of vegetation.