The Study Of The Impact Of Climate Change On The Grassland Production In The North Of China

From the macroscopical scale, the climate is the most primary factor that determines the vegetation types and species distribution on the earth, moreover the distribution of vegetation and species is the most sharp-cut reflection and symbol of the earth climate. The climate change will consequentially result in the change of grassland vegetation types and production, and the change of geographical distribution about grassland vegetation and production, qua the important underlying surface parameter to forecast climate change, can necessarily effect the veracity of climatic forecast and influence evaluation.Using the investigation data of Chinese grassland resource and climatic reorganized data, and by way of the comparation and researth of the applicability of three popular vegetation—climate classification models, the thesis ascertains the most suited vegetation—climate classification model for the grassland of researched area;analyzes in detail the relation between the geographical distribution of grassland production and primary climatic factors such as light, heat, water in the area of NeiMongol—Xinjiang and QingHai—XiZang, and establishes the grassland climatic production model;lastly, based on the nesting result of general circulation model(GCM) and regional climate model(RCM), the thesis studies the possible change of grassland vegetation types and production in the North of China when CO₂ increases double. The main fruits are listed in below:1 .Compare and analyze the applicability of Whittaker classification system, Kira classification system, Holdridge Life Zone System in grassland vegetation climate classification of the North of China. Results show that applying amended Holdridge Life Zone System to make the grassland vegetation climate classification of the North of China is the most perfect.2.Using crude grassland production of every county unit and its climatic reorganized data, the thesis studies the relation between the geographical distribution of crude grassland production and primary climatic factors such as light, heat, water in the area of NeiMongol—Xinjiang and QingHai—XiZang. Results show that the water condition is the primary climatic factor that effects grassland production of the North of China, and based on the conclusion, establishes divisionally the grassland climatic production model with moisture index and precipitation.3.Based on the nesting result of general circulation model(GCM) and regional climate model(RCM), the thesis analyzes the change of air temperature and precipitation in the grassland of the North of China after CO₂ increases double, then using the decided vegetation—climate classification model and established grassland climatic production model, in the case of the future climate changes, discusses the possible change of grassland vegetation types andproduction in the North of China. Results show that after CO2 increases double, the area of forest and rare tree steppe of grassland area in the North of China will increase, the area of the rest will decrease, and the distribution pale of most grassland vegetation have the trendency of moving westwardly and northwardly;moveover besides the area with very drought climate, the grassland production of most areas will increase at different extent, thereinto, the area of Qing—Zang have over 20% increase, the north area of Xinjiang have 10%—15% increase, the grassland production in NeiMongol have less than 5% increase.