不同生态系统CO_2通量和浓度特征分析研究  

Characteristics of CO_2 flux and concentration in different ecosystems

作　　者：李婧[1] 刘树华[1] 茅宇豪[1] 张称意[2] 刘立超[3] 梁福明[1] 辛国君[1] 王建华[1] 

机构地区：[1]北京大学物理学院大气科学系大气边界层物理和大气环境研究组,北京100871 [2]国家气候中心中国气象局气候研究开放实验室,北京100081 [3]中国科学院寒区旱区环境与工程研究所,兰州730000

出　　处：《地球物理学报》2006年第5期1298-1307,共10页Chinese Journal of Geophysics

基　　金：中国气象局气候变化专项经费(CCSF-2005-2-QH29;CCSF2006-38);高等学校博士学科点专项科研基金(20050001030);国家自然科学基金(40275004);北京大学校长基金资助

摘　　要：本文利用1993～1994年日本国家农业环境研究所与中国科学院沙漠研究所合作在内蒙古奈曼地区实测的7种不同生态系统（沙丘、轻度放牧草原、中度放牧草原、重度放牧草原、无放牧草原、玉米田和大豆田）的净辐射、土壤热通量、两个高度的CO2浓度、温度、湿度和风速等资料，采用空气动力学方法，计算了CO2通量及其与环境和人为干扰因子的关系，并分析了不同下垫面的光合作用特征．结果表明：各种下垫面CO2通量的共同特点是：在白天，CO2通量和梯度的输送方向是从大气向植被，在中午（11-13时）输送达到负的最大值；在夜间，CO2通量和梯度输送方向与白天相反，是从植被向大气，在早晨（3～5时）达到正的最大值．植被覆盖率及生物量不同的下垫面光合作用强度有明显差异，天气状况对光合作用也有一定影响．By utilizing the micrometeorology data of net radiation, soil heat flux, and CO2 concentration at two heights, temperature, relative humidity, and wind speed measured by the Japanese and Chinese cooperation team at Naiman District of Inner Mongolia, this paper presents a study of the characteristics of CO2 flux and concentration from different ecosystems （namely dune, grassland, light grazing site, medium grazing site, heavy grazing site, maize field and soybean field）. First, CO2 flux of these ecosystems is calculated according to the micrometeorology data using the aerodynamics method. Figures of diurnal variations of CO2 flux are compared. Furthermore, in order to analyze the photosynthesis strength and environmental and man-made factors of different ecosystems, the relationship between CO2 concentration and net radiation, temperature and wind speed is investigated. The results show that because of different plant coverage and above ground biomass, CO2 flux from different ecosystems varies greatly. Grazing seriously destroys vegetation conditions of the grassland, resulting in exposure of sand. Therefore, the strength of photosynthesis of this kind of grassland is weak and the range of daily CO2 flux is comparatively narrow. The diurnal variation of CO2 concentration is closely related to the diurnal variation of net radiation, temperature and wind speed. The former diminishes as the latter increases, but a little slower. The rates of photosynthesis and CO2 transportation can also be influenced by weather conditions. For example, clouds reduce photosynthesis rate, while wind enhances the transportation of CO2 from plants to the atmosphere.

关 键 词：不同生态系统 不同放牧强度 CO2通量和浓度 空气动力学方法 环境和人为因子 

分 类 号：P404[天文地球—大气科学及气象学]