内蒙古半干旱草原土壤植被大气相互作用(IMGRASS)综合研究

为深化对中纬半干旱草原气候生态相互作用过程、机制及其对全球变化的响应与贡献的认识 ,一项名为“内蒙古半干旱草原土壤植被大气相互作用 (IMGRASS)”的基金重大项目于 1997—2 0 0 1年在内蒙古锡林郭勒草原执行。IMGRASS计划在 1998年草原生长季节、在所选定的以典型草原为主 ,包括草甸草原、稀疏沙地草原等在内的中尺度试验区开展了多点、多要素的综合观测。观测内容包括土壤、植被、大气的相关要素和发生于地气界面的潜热、感热通量 ,还包括N2 O ,CH4 ,CO2 等微量气体交换量、辐射与降水分布。除 1998年中尺度观测试验外 ,在 1999— 2 0 0 1年在代表性地点进行了微量气体收支、遥感和沙尘天气相关的专项观测 ,结合草原站已进行的长期监测资料 ,分析气候生态长期相互作用 ,特别是人类活动干预的影响。在分析观测结果的基础上 ,对该地区的气候生态相互作用进行了数值模拟研究。文章作为介绍IMGRASS计划的第一部分 ,对该项研究计划作一全面简要介绍 ,包括科学目标、计划实施实验区背景、中尺度综合观测 ,并对实验所得大气边界层结构、辐射通量、沙地土壤水份状况、地表反射率谱与遥感测量等提供了个例分析 ,并简单介绍IMGRASS数据库。有关与全球变化有关的几个方面的初步研究结果将在本期刊中另文进行

COMPOSITE STUDY ON INNER MONGOLIA SEMI-ARID GRASSLAND SOIL-VEGETATION-ATMOSPHERE INTERACTION(IMGRASS)

In order to deeply understand the climate\|ecology interaction, its processes and mechanisms, and its response and contribution to the global change of mid\|latitude (temperate) semi\|arid grassland, a major project called "Inner Mongolia Semi\|Arid Grassland Soil\|Vegetation\|Atmosphere Interaction (IMGRASS)" has been approved by NSFC and implemented during 1997-2001. IMGRASS is aimed at through mesoscale coordinated field observation, long term monitoring, analysis as well as numerical simulation to reveal multiple spatial and temporal scale and physical\|chemical\|biological processes, including the influence of human activities. Mesoscale field observation was conducted in 1998 growing season in Xilingol typical steppe of Inner Mongolia, which included observations of soil, vegetation, atmosphere parameters, various fluxes at land surface\|atmosphere boundary (sensible and latent heat, radiation, greenhouse gases), and precipitation. In this paper, the scientific objectives, background of experimental area, and field experiment implementation are introduced. Examples and preliminary analysis of some observations, such as atmospheric boundary layer profiles, soil moisture, radiation, surface reflectance, remote sensing related surface reflectance, AVHRR\|derived regional NDVI and LAI, as well as IMGRASS data\|base are also introduced. Numerical simulation and composite study of climate\|ecology interaction and human activity influence of IMGRASS project are described in an accompany paper in this issue.