Changes of freeze-thaw characteristic parameters of seasonally frozen soil and their influencing factors in alpine mountain:a case study of southern slope of the Tianshan Mountains
Seasonally frozen soil is widely distributed in alpine mountains and its freeze-thaw process has pro-found effects on hydrological water resources and ecological environment.Research on the changes of freeze-thaw characteristic parameters and influence mechanism of seasonally frozen soil under the background of cli-mate change can provide scientific basis for water resources management and ecological protection in alpine mountains.This study selected southern slope of the Tianshan Mountains as a typical area.Based on the ob-served daily data from 13 meteorological stations,including data of seasonally frozen soil(e.g.maximum frost depth,freezing period,starting date of soil freezing,and ending date of soil freezing),air temperature,land surface temperature and precipitation,as well as reanalysis snow cover data since 1958,the spatiotemporal varia-tions of freeze-thaw parameters of seasonally frozen soil and the driving mechanisms were analyzed using multi-ple linear regression statistics and spatial analysis.The results showed that:(1)The maximum frost depth of seasonally frozen soil ranged from 48.5(±11.4)cm to 96.8(±8.5)cm,the freezing period ranged from 102(±10)days to 141(±14)days,the multi-year average starting date of soil freezing were largely ranged from No-vember 7 to November 19 and the multi-year average ending date of soil freezing ranged from March 1 to March 28.(2)The starting date of soil freezing was gradually postponed,while the ending date of soil freezing was ad-vanced and the freezing period was shortened during 1950s—2010s.(3)The maximum frost depth showed a pat-tern of"higher altitude,deeper frost depth",and it has increased significantly in the past decades in the central part of the study area.The freezing period has shortened significantly in most of the study area.(4)According to comparative analysis,temperature(air temperature and land surface temperature)is the dominant factor of the freeze-thaw parameters variation of seasonally frozen soil on south slope of the Tianshan Mountains,and the de-tailed impact weights are:air temperature accounts for(24.1±3.6)%,land surface temperature accounts for(12.1±3.1)%,precipitation accounts for(9.6±1.7)%,and snow cover accounts for(5.1±1.5)%by quantita-tive analysis.
seasonally frozen soilmaximum frost depthfreezing periodspatiotemporal variationsouthern slope of the Tianshan Mountains
NETL
NSTL
万方数据
