近50多年青海玉树冻土变化特征分析  

VARIATION CHARACTERISTICS OF FROZEN SOIL IN YUSHU QINGHAI IN RECENT 50 YEARS

作　　者：叶殿秀[1] 赵珊珊[1] 孙家民[1] 

机构地区：[1]国家气候中心,北京100081

出　　处：《长江流域资源与环境》2011年第9期1080-1084,共5页Resources and Environment in the Yangtze Basin

基　　金：国家科技支撑计划项目(2008BAK50B02)和(2007BAC29B05)共同资助

摘　　要：利用青海玉树县从建站至2009年的冻土观测资料,分析了玉树土壤年最大冻结深度,冻结初、终日,无冻土期变化特征。结果表明:近50多a,玉树县土壤冻结具有明显的季节变化特征,冻结主要出现在10月～翌年4月;6月中旬～9月上旬为无冻土安全期;多年平均无冻土期173 d,80%保证率下的无冻土期为147 d(不足5个月);玉树土壤年最大冻结深度没有明显的变化趋势,仅呈阶段性变化特征。0～5 cm土壤冻结初、终日没有明显变化趋势,10～30 cm深度土壤冻结初日呈变早、终日呈推迟的趋势。而近50 a玉树冬季平均气温、平均最低气温及年极端最低气温均呈显著上升趋势。由此说明对季节性冻土区的玉树而言,气候变暖并不一定意味着其年最大冻结深度变薄、表层土壤冻结初日推迟、终日提早,土壤冻结深度的变化除与温度有关外可能还受其他要素的影响。该结论与我国部分学者对青藏高原南部冻土研究结论一致。Observed frozen soil data in Yushu Qinghai were analyzed to show the seasonal variation,beginning date and ending date of frozen soil,characteristics of no frozen soil period.Frozen soil in Yushu had obvious seasonal variations which begin from autumn,reaching maximum depth at the end of winter and melt in spring.Non-frozen soil averaged period is 173 days.80% guarantee days were 147 days.Non-frozen soil period is between middle June to the beginning of September.In the last 50 years,maximum frozen soil depth had stepped characters;the beginning and ending date of surface to 5 cm soil didn＇t have obvious trend.The beginning date of 10 cm and the deeper soil had early trend and the ending date had delay trend.All seasonal,annual mean temperature and annual minimum temperature had obvious increasing trend.This indicated that maximum depth,beginning date and ending date of frozen soil,were not always attenuation,delay or early with climate warming.They may be affected by else elements.This results was consistent with the some of scholar＇s studies for southern of Tibetean plateau.

关 键 词：青海玉树 冻结初日 冻结终日 无冻土期 变化特征 

分 类 号：P642[天文地球—工程地质学]