气温升高对青藏高原沼泽草甸浅层士壤水热变化的影响.PDFVIP

第 46 卷第 1 期 兰州大学学报(自然科学版) Vo l. 46 No. 1 2010 年 2 月 Journal of Lanzhou University (Natural Scie时es) Feb.2010 文章编号: 0455-2059(2010)01-0033-07 气温升高对青藏高原沼泽草甸浅层士壤 水热变化的影响 王俊峰，吴青柏 (中国科学院寒区旱区环境与工程研究所冻土工程国家重点实验室，兰州 730000) 摘 要:采用被动升温方式，利用OTCs 系统对青藏高原沼泽草甸生态系统分别进行3~5 oC(OTC-80) 和1~2 o C(OTC-40) 升温处理，研究下垫面浅层土壤水热变化特征并对其产生的生态环境效应进行探 0 o 讨.结果表明:与对照点 (Out-C) 相比，在近地表气温平均分别增高4.87 C， 1. 40 C 的情境下，浅层土 壤持续冻结期显著缩短而融化期显著延长;近地表气温升高导致注层土壤温度上升，积温增大，加速 了表层土壤蒸发速度和植被蒸腾速率，注层土壤因缺水而影响植被生长;注层土壤温度升高将进一步 加速寒区有机质的分解速率，降低土壤碳库稳定性，促使青藏高原气候进一步向暖干化发展;近地表 气温升高还将导致物种减少甚至消失，严重威胁着区域经济发展和生态安全. 关键词:气温升高;注层土壤;水热变化;生态环境效应;沼泽草甸;青藏高原 中图分类号: P94 1.5j Xl71 文献标识码:A Impact of elevated temperature on the heat and water changes of the shallow soil layers in the swamp meadow areas of the Qinghai-Tibetan Plateau WANG Jun-feng; WU Qing-bω (State Key Laboratory of Frozen Soil Engineering , Cold and Arid Regions Environmental and Engineering Research Institute , Chinese Academy of Sciences , La皿hou 730000 , China) Abstract: The passive warming method was adopted to elevate the near-surface air吨emperatures 3~5 oC (OTC-80) and 1~2 OC(OTC-40) , in the swamp meadow areas on the Qinghai- Tibetan Plateau , by us旧sin the open-top chambers (OTCs) systems. The shallow soil layer heat and water changes were studied and the corresponding eco-environmental effects resulting from the heat and water changes were discussed. The results showed that , compared with the nat旧al plots (Out-C) , the shallow soi