摘要
利用祁连山东段冷龙岭地区1990s—2010s的Landsat TM,OLI遥感影像数据,结合NDVI阈值和人工目视解译提取1990s,2000s,2010s研究区寒冻荒漠分布范围,分析近30a研究区寒冻荒漠分布范围变化特征及其对气候变化的响应过程和机理,同时考虑了地形差异对寒冻荒漠对气候响应的影响。结果表明:(1)近30a以来,祁连山东段冷龙岭地区寒冻荒漠呈萎缩趋势,以约4.5km2/年的速率萎缩,但局部地段也有扩张情况;其中萎缩区大量分布在3 900~4 100m的海拔带,扩张区零星分布于各高度带。该现象导致祁连山东段冷龙岭地区寒冻荒漠分布下界平均海拔向高海拔推进,推进速率约为23m/10a。(2)受水热条件控制,寒冻荒漠萎缩变化主要分布在12°以下低坡度地区,同时由于寒冻风化作用加强,碎屑坡积等物理过程影响,低坡度区域也存在扩张变化,随着坡度变陡,寒冻荒漠基本无变化;同时,在不同坡向上均存在寒冻荒漠的萎缩与扩张变化。寒冻荒漠在阳坡变化大于阴坡。(3)1990—2015年祁连山东段冷龙岭地区气温呈波动增加趋势,线性增长率约为0.3~0.5℃/10a,增温幅度显著,呈先快后慢趋势,降水量无明显变化趋势,但在时间序列上呈现波动。该时期气候变化导致了上述寒冻荒漠分布范围的变化,且分析结果表明其主要受控于气温变化。
we study on changes in the distribution range of alpine desert and its responses to climate change in the Lenglongling Range of Eastern Qilian Mountains in recent 30 years by using the distributed range of alpine desert in different years,which were obtained as threshold of NDVI and artificial visual interpretation,and were extracted form TM remote sensing digital images in the Lenglongling Area of Eastern Qilian Mountains from 1990 sto 2010 s.We analyzed the variation characteristics of the change of the distribution range of alpine desert,and then discussed the process and mechanism that the change of the distribution range of alpine desert responses to climate change.Meanwhile,we obtained the topographical data(altitude,slope,aspect)from DEM in the study area in order to discover the relationship between the change of the distribution range of alpine desert and topographical factors.The results indicated that alpine desert was shrinking gradually in the Lenglongling Range of Eastern Qilian Mountains in recent 30 years,but it was expanding in the local section;the shrinking area of alpine desert mainly distributed in the altitude of 3 700~4 100 meters and the expansion region scattered in the different altitude zones.This phenomenon has caused that the average elevation of the lower bound of alpine desert in the Lenglongling Range of Eastern Qilian Mountains nearly had significantly moved to higher altitudes,the move rate was about 23 m/decade during the study period.Under hydrothermal conditions control,the shrinking area of alpine desert in slope mainlyconcentrated in the range of below the gradient of 12,also due to frost weathering strengthen,debris slope and physical processes that affect,the expansion changes occurred in the low slope region.As the slope gradient increases,the change of the distribution range of alpine desert has decreased gradually.Meanwhile the shrinking and expansion changes of alpine desert have reflected in different aspects.The changes of alpine desert in sunny slope are greater tha
出处
《水土保持研究》
CSCD
北大核心
2017年第6期305-312,共8页
Research of Soil and Water Conservation
基金
国家自然科学基金(40901056)
中央高校基本科研业务费专项资金项目(lzujbky-2013-130)
国家基础科学人才培训资助项目(J1210065)
兰州大学地理学基地科研训练及科研能力提高项目
关键词
寒冻荒漠
气候变化
遥感监测
冷龙岭地区
alpine desert
climate change
remote sense monitoring
Lenglongling area
