温暖化加剧青藏高原高寒草甸土非生长季冻融循环

发布时间：2018-02-11 19:19

本文关键词： 冻土层冻融过程土壤温度增温　出处：《北京大学学报(自然科学版)》2017年01期 　论文类型：期刊论文

【摘要】：在2013年10月至次年4月,首次利用微根管直接观测和土壤温度间接观测相结合的方法,研究增温对青藏高原高寒草甸土壤冻融循环过程的影响。结果显示:1)全年增温和冬季增温均显著增加非生长季5,10,20 cm的土壤温度,而且冬季增温处理下的5~20 cm土壤非生长季月平均温度比全年增温处理下的高0.01~0.18oC;2)全年增温和冬季增温显著降低了完全冻结期和冬春解冻期的冻土层厚度,而对秋冬始冻期的冻土层厚度没有影响;3)全年增温和冬季增温显著减少了完全冻结期的持续天数和增加冬春解冻期的持续天数,而对秋冬始冻期的持续天数没有影响;4)冬季增温比全年增温对冻土层厚度和冻融循环持续天数的影响更加显著。研究表明,在青藏高原高寒草甸气候温暖化的趋势下,非生长季土壤冻融交替天数的增加,可能会进一步对高寒地区的地下碳氮循环产生重要的影响。
[Abstract]:From October 2013 to April, the combination of direct observation of microroot canal and indirect observation of soil temperature was used for the first time. The effect of temperature increase on freeze-thaw cycle of alpine meadow soil in Qinghai-Xizang Plateau was studied. In addition, the monthly mean temperature of 5 ~ 20 cm soil under winter warming treatment was higher than that of annual temperature increasing treatment (0.01 ~ 0.18oC ~ (2)) the thickness of frozen soil layer in total freezing period and thawing period in winter and spring thawing period was significantly decreased, and the temperature increase in winter and winter significantly decreased the thickness of frozen soil layer during the whole year and the winter and spring thawing periods, respectively. However, there was no effect on the thickness of frozen soil layer during the beginning of autumn and winter) the annual and winter warming significantly reduced the duration of complete freezing period and increased the duration of winter and spring thawing period. However, the days of beginning freezing in autumn and winter have no effect on the duration of winter. (4) the effect of temperature increase in winter on the thickness of frozen soil and the days of freeze-thaw cycle is more significant than that in the whole year. The results show that, under the trend of warming climate of alpine meadow in Qinghai-Tibet Plateau, The increase of alternate days of soil freezing and thawing in non-growing season may further influence the underground carbon and nitrogen cycling in alpine regions.
【作者单位】：地表过程分析与模拟教育部重点实验室北京大学城市与环境学院生态学系;植被与环境变化国家重点实验室中国科学院植物研究所;高原适应与进化重点实验室中国科学院西北高原生物研究所;
【基金】：国家重点基础研究发展计划重大科学研究计划(2014CB954003,2014CB954004) 国家自然科学基金(31300415)资助
【分类号】：S812.2

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