辽东湾沿海水稻田温室气体排放的时空动态模拟

 【目的】利用遥感信息技术和DNDC生态过程模型相结合对水稻田排放的温室气体通量进行模拟和定量估测，并分析其排放的时空动态格局。【方法】利用遥感技术对覆盖辽宁省大洼县的卫星图像（Landsat TM和CBRES2）进行土地利用／覆盖分类，提取研究区1988年和2005年的水稻田空间分布特征信息并计算其面积。应用DNDC模型对这两个时期进行温室气体（CO2、N2O、CH4）排放通量模拟，分析辽东湾沿海地区水稻田温室气体排放的时空动态。【结果】与1988年相比，2005年的水稻田的面积约增加7 066.2公顷。1988年整个研究区CO2、N2O和CH4排放总量分别为-1.20 Tg C、2.57×10-4 Tg N和1.4×10-2Tg C，而2005年为-0.72 Tg C、2.69×10-4 Tg N和1.7×10-2Tg C。空间分布上表现为CO2在东、南部为高吸收，中北部低吸收的特征；N2O在中东部和西部地带排放低，北部排放高的特征；CH4在中东部和西南排放高，北部和东南部地带排放低。同时，净全球增温潜势具有在2005年比1988年空间差异小的特点。【结论】人口和经济因素是影响水稻田面积变化的主要原因。水稻田是一个重要的CO2汇，是N2O和CH4的排放源，并且排放通量的时空差异明显。

Simulating Spatial-Temporal Dynamics of Greenhouse Gas Emission From Rice Paddy Field in Liaodong Coastal Region, China

Abstract: 【Objective】This study used the DNDC model which is based on the ecological process to simulate the flux of Greenhouse Gas emits from rice paddy field under various management practice scenario and estimate quantitatively. Give one way in accessing the impact of agricultural ecosystem on climate and environment. 【Method】The Landsat TM and CBRES remote sensing images required in 1988 and 2005 were utilized to classify the Land Use/Cover covers Dawa county, Liaoning province. The aim is to extract the temporal-spatial distribution of rice paddy field and calculate its area. The DNDC model was applied to simulate the flux of Gas (Carbon dioxide, Nitrous oxide, Methane) emits from rice paddy field in different period of time, and analyzed the spatial-temporal dynamics of Greenhouse Gas emits from rice paddy field in Liaodong coastal region.【Result】Comparison of the area of rice paddy field in 2005 with that of 1988, there were 7,066.2 hectares increment in amount. The total emission of three GHG (CO2、N2O、CH4) in 1988 and 2005 were-12.02 Pg C, 2.57 Tg N, 0.14 Pg C and 7.22 Pg C, 2.69 Tg N, 0.17Pg C, respectively. The spatial distribution of them were, flux rate of CO2 high region in the east and south of study site, low in the north, N2O high in the mid-east and northwest, low in the north, CH4 high in the mid-east and southwest, low in the north and southeast, respectively. For the net Global Warming Potential (GWP), the spatial difference in 2005 were smaller than in 1988.【Conclusion】Socio-economical impact is the key factor of diving area change of rice paddy field. The rice paddy field is one sink of CO2, source of N2O and CH4. In addition to climate factors, different soil type make significant impact on the flux magnitude of Greenhouse Gas emits from rice paddy field, so does the farm management practice scenario.