中国东北样带的梯度分析及其预测

陆地样带研究已成为国际地圈-生物圈计划(IGBP)全球变化研究的重要手段与热点。中国东北样带(NECT)已被列为IGBP国际全球变化陆地样带之一。该样带在东经112°与130°30＇之间沿北纬43°30＇设置,长约1600km,是一条中纬度温带以降水为驱动因素的梯度,具有由温带针阔叶混交林向温带草原的3个亚地带——草甸草原、典型草原与荒漠草原过渡的空间系列。该样带上有4个生态实验站。在大量的固定样地、实验调查研究资料与数据的基础上给出了样带的初步梯度分析及在全球变化图景下的预测,包括其地理位置、设置意义、地形地貌、气候梯度、土壤类型、植被类型和土地利用格局,一个遥感数据驱动的模型和NPP模型在整个样带上运行过。今后NECT将在生物地球化学循环(水、C、N、P等与痕量气体CO_2、CH_4等)、生态系统结构、功能与动态、生物多样性、土地利用与土地覆盖、动态全球植被模型(DGVM)以及高分辨率遥感数据应用等方面得到加强,将成为我国全球变化与陆地生态系统(GCTE)与其它IGBP核心项目研究的前沿阵地。

A GRADIENT ANALYSIS AND PREDICTION ON THE NORTHEAST CHINA TRANSECT (NECT) FOR GLOBAL CHANGE STUDY

The terrestrial transect has already become an important approach and hot spot for International Geosphere-Biosphere Programme (IGBP) in the global change study. Northeast China Transect (NECT) is listed as one of the first set of IGBP transect. It is placed along the latitude 43 30' N, between longtitudes 112 and 130 30' E, and approximately 1 600 km in length. NECT is basically a gradient driven by precipitation/moisture factors located in the mid-latitude of the temperate zone. The vegetation zones or biomes along the NECT consist of temperate mixed evergreen coniferous and broadleaf deciduous forest and temperate steppe, including three subzones, viz. meadow steppe, typical steppe, and desert steppe, along an east-westward continuous transitional spatial series , respectively. There are four ecological experimental stations with support from a great number of permanent samples and long-term experimental data on the transect. The initial gradient analysis and simulation for the predicted scenario under increasing temperature given for the transect included the geographical location, significance of setup, topography, geomorphology, climate, soil, vegetation and pattern of land use. One remote sensing driven model and one NPP model have been tested and operated for the whole transect. The study on NECT will be enhanced by research project, concerning biogeochemical cycles (water, C,N, P, etc, and CO2, CH4 greenhousegas emis-son), structure, function and dynamics of ecosystems, land use and land coverage, biodiversity, dynamic global vegetation modeling (DGVM), and high resolution remote sensing data. It will become a frontier for the studies of Global Change and Terrestrial Ecosystems (GCTE) and other IGBP core projects in China.