A Study Of Contemporary Climate Change In Northeast China And Effect To Eco-geographical Boundaries

A study of contemporary climate change in northeast china and effect to Eco-geographical boundariesAbstract: As an important component of the nature environment, climate is vital to human survival. Every change of the climate can make an effect on nature eco-system and social economy. The effect will be multi-scale and multi-level. As an important nature resource, also climate is the main component of nature environment. Therefore the effect on social economy system will be from two aspects. At different degrees, climate-change has an effect on every aspect of global and regional social economy. Varying with the location, time, society development levels and the environment condition, the social system is sensitive and vulnerable to climate-change. Thus the study on regional climate change and its character should be reinforced. It is vital to the making of region development policy and the eco-construction.Taking the three provinces of northeast for study area, this paper makes use of data of the 110 weather stations in northeast from 1951~2000. From aspect of space and time, the paper makes a comprehensive analysis on the climate-change of northeast with the help of GIS and mathematics method such as wavelets, Kriging and so on. Also this paper points out the changing trends and the influence on eco-geography regional borderlines.Based on the latest 50 years air temperature of northeast, a list of time-sequence is built. The list points out that the annual temperature of the latest 50 years is increasing at speed of 0.6℃/10a, and the spring temperature is increasing more fast at speed of 0.69℃/10a, for the winter is 0.61℃/10a. From the time-sequence list of precipitation, it shows that the precipitation of northeast decreases steadily at speed of 0.27mm/a. The spring precipitation increases a little ,but the other seasons decrease with different degrees.The results from the wavelets: the annual temperature has a quasi period of 15a, within which there is a shorter period of 2~4a with a self-similarity structure. As for the precipitation list, it has a long period of 40a, including a quasi period of 5a,within which there is a quasi period of 2~3a. From the aspect of space, the northeast area has a general temperature-increasing, as for the trends of temperature-increasing, plain is higher than mountain region, farmland is higher than pasturing area. From the aspect of season, the temperature-increasing area is bigger and the extent is wider in winter, then it is spring. The temperature-changing character of northeast is "warm winter and cool summer". At the same time, the precipitation at some certain areas increase with different degrees. The precipitation in the middle plain increase greatly, and the amount is about 30mm in the latest 20 years. From the aspect of season, the precipitation increasing of summer makes the biggest contribution to annual precipitation.The eco-geographical subarea based on the thermal and humid classification index of C.W.Thornthwaite, the paper studies the effect of climate changing on the eco-geography boundaries. On the background of climate-warmer, the two important thermal boundaries: warm temperate zone and temperate zone, temperate zone and cold temperate zone. The above two boundaries move towards north more or less. But the change of humid boundaries is not in evidence like the heat boundaries. Before and after 1980, the Subhumid boundary and semiarid boundary move towards west or east by turns.