青海季节冻土退化的成因及其对气候变化的响应

利用相关分析等数理统计学方法,分析了地形、气候等自然因子对季节冻土时空分布的影响,模拟了冻土对气温、降水、云量等气候因子变化的响应。研究表明:地形、气候因子对青海季节冻土的分布和演变有显著影响,气候变暖是造成季节冻土退化的主要原因;西宁城市化造成的"热岛效应"的加剧以及青海湖水位下降引起的"水体效应"的削弱等局地变化在某种程度上强化了季节冻土对气候变化的响应;季节冻土对气温变化的响应在旬、月尺度上较年际尺度上表现得更为明显,同时,随着冻土深度的加深其滞后效应越明显。

Cause of seasonal tjale degeneration and its response to climate change in Qinghai

Based on the mathematical statistic method of correlation analysis,the impact of natural factors of climate and topography upon spatial-temporal distribution of seasonal tjale is analyzed,and the response of tjale to air temperature,precipitation and cloudiness is also simulated.The results show that the topography and climate factor have a significant influence on the distribution and evolution of seasonal tjale in Qinghai,the topographic factors include altitude,longitude,latitude,slope,direction of inclination and so on.Since atmosphere is most active and sensitive compared with the others in the climate system,the climate factor and its change have significant effect on the seasonal tjale,at the same time,in that the tjale's response upon the temperature variation is most sensitive,so it is considered that global warming is the primary factor to cause seasonal tjale degeneration. The variation of local climate effect of the increasing of heat island effect brought by the urbanization in Xining and the decreasing of water effect caused by the descending of water level in Qinghai lake intensify the response of seasonal tjale upon climate change to some extent,the seasonal tjale has an evident time-delay upon the response of the air temperature variation at dekad and month scale,while it is not so significant on the interannual scale.At the same time,the response of surface temperature upon the temperature change is delayed gradually with the depth increasing,it shows : more deeper,the delay effect is more obvious.