| 近30年来中国干旱生态区增暖放大现象及其与植被覆盖的联系 |
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| 引用本文： | 黄清瀚,陈海山,华文剑.近30年来中国干旱生态区增暖放大现象及其与植被覆盖的联系[J].气候与环境研究,2018,23(1):72-82. |
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| 作者姓名： | 黄清瀚 陈海山 华文剑 |
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| 作者单位： | 南京信息工程大学气象灾害教育部重点实验室/气候与环境变化国际合作联合实验室/气象灾害预报预警与评估协同创新中心, 南京 210044 |
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| 基金项目： | 国家自然科学基金项目41475083、41625019，江苏省自然科学基金项目BK20160948，江苏省高校自然科学研究面上项目16KJB170007 |
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| 摘 要： | 利用归一化植被指数（Normalized Difference Vegetation Index，NDVI）将中国划分为不同的生态区，在此基础上分析夏季植被状况与不同生态区增暖之间的联系。研究表明，就多年平均而言，中国植被覆盖呈现自东向西逐渐减少的空间分布。1982年以来，植被稀疏的干旱生态区是夏季增暖最明显的区域，平均气温和平均最高气温增速大都位于0.6~1.0℃/10 a，而平均最低气温的升高达到0.8~1.4℃/10 a，明显高于中国其他区域。进一步分析发现，夏季气温的变化与其所处地区的植被疏密程度之间存在很好的负相关关系，即快速增暖主要发生在植被稀疏区，且这种负相关关系在夏季平均最低气温上最为显著。不同植被覆盖区中气温的长期变化趋势，受NDVI变化带来的地表反照率和云量变化的影响，但各生态区不尽相同，主要表现在:植被稀疏的干旱生态区，植被减少，引起地表反照率增加，感热输送增加而潜热输送减小，加速了该地区整体的增温速率；而在植被茂密地区，植被增加造成地表反照率减少，同时由于蒸发冷却，其整体增暖幅度缓于植被稀疏区。所以，植被活动对全球变暖背景下的区域气候变化具有重要作用，尤其表现在干旱生态区的陆面过程上，地表辐射平衡和能量收支的显著改变放大了干旱生态区的增暖速率。
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| 关 键 词： | 夏季气温 归一化植被指数(NDVI) 变暖趋势 干旱生态区 |
| 收稿时间： | 2016/12/9 0:00:00 |
Stronger Warming Amplification over Arid Ecoregions and Its Relationship to Vegetation Cover in China since 1982 |
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| HUANG Qinghan,CHEN Haishan and HUA Wenjian.Stronger Warming Amplification over Arid Ecoregions and Its Relationship to Vegetation Cover in China since 1982[J].Climatic and Environmental Research,2018,23(1):72-82. |
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| Authors: | HUANG Qinghan CHEN Haishan and HUA Wenjian |
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| Institution: | Key Laboratory of Meteorological Disaster, Ministry of Education/Joint International Research Laboratory of Climate and Environment Change/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science and Technology, Nanjing 210044 |
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| Abstract: | To analyze vegetation variability and its relationship with summer air temperature variability in China, this study classifies various ecoregions based on the climatological Normalized Difference Vegetation Index (NDVI) values. Results show that there is a decreasing spatial distribution of vegetation from east to west in China. Arid ecoregions are the most obvious areas for summer warming since 1982. The warming rates over arid ecoregions for summer mean air temperature and mean maximum air temperature are 0.6-1.0℃/10 a and that for summer mean minimum air temperature is 0.8-1.4℃/10 a. Furthermore, summer air temperature variations have a significant negative correlation with vegetation conditions since 1982. In other words, the lower the vegetation greenness is, the stronger the warming trend is. It is worth noting that the negative correlation is most significant between mean minimum air temperature and vegetation conditions. In each ecoregion, the long-term trend of temperature is largely affected by changes in albedo and clouds. In the sparse vegetation regions, the increased albedo leads to a decrease in latent heat transport and increases the sensible heat flux, which intensifies the warming trend. In the dense vegetation regions, the decline in albedo leads to increases in evaporative cooling, which slows the rate of increase in the air temperature. Overall, vegetation activities play an important role in regional climate change, especially over the arid regions, where significant changes in surface radiation balance and energy flux amplify the rate of warming. |
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| Keywords: | Summer air temperature Normalized Difference Vegetation Index (NDVI) Warming trends Arid ecoregions |
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