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| 气候变化对黄土碳库效应影响的敏感性研究 | |
| 引用本文： | 秦小光,李长生,蔡炳贵.气候变化对黄土碳库效应影响的敏感性研究[J].第四纪研究,2001,21(2):153-161. |
| 作者姓名： | 秦小光 李长生 蔡炳贵 |
| 作者单位： | 1. 中国科学院地质与地球物理研究所,北京 100029 2. 美国新罕布舍尔大学 地球海洋及空间研究所,Durham |
| 摘 要： | 中国黄土分布广、厚度大,是古气候变化的良好记录载体,然而黄土在大气CO2循环中到底是源还是汇一直是困扰人们的一个问题.本文利用陆相生态系统中的生物地球化学模型,通过敏感性试验,模拟了土壤有机碳对气候变化的响应.结果表明:1)在各种稳定的气候条件下黄土的土壤有机质都是持续增加的,因此可以认为自然条件下黄土是大气CO2的一个汇;2)温度和降水对黄土中土壤有机质含量的影响正好相反,表明湿度是影响黄土地区生态环境的主要因素,温度和降水都是通过对湿度的影响来影响植被生态的;3)地表植被和土壤有机质是黄土碳库与大气CO2之间的重要媒介.黄土表层的生物地球化学过程是影响黄土碳汇效应的主要过程;4)黄土碳库的主要存在形式以次生碳酸盐为主,其次是土壤有机质,气态CO2只占很小比例. |
| 关 键 词： | 黄土碳库 土壤有机碳 生物地球化学模型 气候变化 敏感性试验 |
| 收稿时间： | 2001-01-11 |
| 修稿时间： | 2001年1月11日 |
THE SENSITIVITY SIMULATION OF CLIMATE IMPACT ON |
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| Qin Xiaoguang,Li Changsheng,Cai Binggui.THE SENSITIVITY SIMULATION OF CLIMATE IMPACT ON[J].Quaternary Sciences,2001,21(2):153-161. | |
| Authors: | Qin Xiaoguang Li Changsheng Cai Binggui |
| Institution: | 1. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029; 2. Institute for the Study of Earth, Oceans and Space, University of New Hampshire |
| Abstract: | The carbon cycle is an important research topic. The sinks and sources of atmospheric CO2 as a major greenhouse gas have been extensively studied. The loess in China covers a large area and is rich in climate information of past global change. In the last decades, most researches were focused on the paleoclimate change recorded in the loess and a number of achievements were acquired. However, some Chinese scientists began to study the carbon cycle in loess areas from some ways only in recent years. It is not clear until now whether the loess area is a sink or a source of atmospheric CO2 in the global carbon cycle. In this paper, a biogeochemical model, DNDC model, is used to study variations of the soil organic carbon (SOC) under different climate patterns by simulating the biogeochemical processes in the surface soil of the loess area, and to analyze the C pools and the function of loess in global carbon cycle. In the present study, a Weinan loess section is chosen as an example because it has been examined in many aspects in recent years. According to record of paleo-plant in the loess, the vegetation type in the model simulation is assumed to be the natural grassland without any agricultural practice. The daily climate record of 1990 from Huayin station is used as a standard climate pattern. We assumed that the climate of 1990 would continue steadily for a period (e.g. 14 years). With this assumption, the dynamics of the soil organic carbon can be simulated by the DNDC model. The different patterns of climate change, such as the temperature rising up or falling down for 3°C, the precipitation increase or decrease by 30%, and their combinations, are used in the simulation. Then, the dynamics of the SOC and the soil CO2 emission under different climate conditions are analyzed and the C pools of loess are discussed. The simulation result shows that (1) The SOC in the surface of loess always increases under all steady climate patterns, meaning that the loess covered with the natural grassland should be a sink of atmospheric CO2. (2) The effects of temperature and precipitation on SOC in loess are reverse, and the humidity is a major factor affecting the ecosystem, through which both the temperature and precipitation affect the vegetation growth. (3) Vegetation and soil organic matter are important buffer between the atmospheric CO2 and C pools of the loess. (4) The major C pool of the loess is carbonate, the next is SOC The gaseous CO2 is only a small portion. A rough estimation shows that the annual absorbed C in the loess area is about l.76× 1013gC (0.017 6PgC) if whole the loess area is covered by grassland, suggesting that the loess as a sink of atmospheric CO2 should not be ignored in global C cycle. |
| Keywords: | C pools of loess soil organic carbon biogeochemical model climate change sensitivity experiments |
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