青藏铁路沿线地表融冻指数的计算分析  

The Surface Thawing-Freezing Indexes along the Qinghai-Tibet Railway:Analysis and Calculation

作　　者：赵红岩[1] 江灏[2] 王可丽[2] 杨瑜峰[3] 

机构地区：[1]中国气象局兰州干旱气象研究所甘肃省干旱气候变化与减灾重点实验室 [2]中国科学院寒区旱区环境与工程研究所,甘肃兰州730000 [3]甘肃省气象科技服务中心,甘肃兰州730020

出　　处：《冰川冻土》2008年第4期617-622,共6页Journal of Glaciology and Geocryology

基　　金：国家自然科学基金项目(40471005)资助

摘　　要：利用青藏高原地表温度观测资料,计算了青藏铁路沿线地表融化和冻结指数,并分析其变化特征和发展趋势.结果表明:在平均气候状况下,青藏高原暖/冷季地表温度和融化/冻结指数的分布主要受地理纬度和海拔高度的影响;太阳辐射的纬度效应叠加在气温的海拔递减作用上,形成了青藏铁路沿线地表的融化/冻结特征分布.青藏铁路沿线各站地表气温的融化/冻结指数与地表的融化/冻结指数有较好的换算关系,各站的n系数比较稳定,标准偏差和变异系数都比较小.1980-2005年平均的五道梁地区的融冻比为0.8,沱沱河地区的融冻比为1.0;但从青藏铁路沿线地表融化/冻结指数的长期变化趋势来看,融冻比目前处于近50 a的较低水平,存在有缓慢的、清楚的波动上升趋势.近10 a的线性变化趋势约为14℃.d.a-1,对处于弱的冻结平衡边缘的冻土路基的安全稳定是一个明显的、重要的威胁.Based on the surface temperature observation data, the surface thawing indexes and freezing indexes along the Qinghai-Tibet railway are calculated, and its variation characteristics and evolution tendency are analyzed. The results show that, on the climatic mean status, the distribution of surface temperatures and thawing/freezing indexes on the Tibetan Plateau in warm/cool season is affected mainly by latitude and altitude. The latitude effect of solar radiation is superposed to the descending effect of air temperature with altitude, forming the special distribution features of the surface thawing/freezing along the Qinghai-Tibet Railway. The conversion relations are better between the thawing/freezing indexes of air temperature and surface temperatures at the stations along the Qinghai-Tibet Railway, namely the coefficient n. The coefficient n at each station is stable with small standard difference and variance coefficient. The thawing-freezing ratio averaged from 1980 to 2005 is about 0.8 on Wudaoliang region and 1.0 on Tuotuohe region. As a long-term view, the tha- wing-freezing ratio at present is at a lower level during the latest 50 years, with a slow but clear rising tendency in the last 10 years, when a linearly increasing rate of about 14 ℃·day per year can be seen. This is an obvious and significant menace to the safety and stability of frozen roadbed which is on the verge of weak freezing balance.

关 键 词：青藏铁路 地表温度 融冻指数 

分 类 号：P642.14[天文地球—工程地质学]