摘要
祁连山地区位于西北干旱半干旱地区,气候干燥,降水量少,区域内部生态环境脆弱。全球气候变暖及经济发展,对区域生态环境造成了重大影响。本研究通过研究植被覆盖度(fractional vegetation cover,FVC)时空分布特征和变化趋势以及对干旱的响应,为生态环境改善和减轻干旱影响提供依据。本研究基于MOD13Q1遥感数据以及气象数据,采用像元二分模型、Thornthwaite方法、趋势分析法、Hurst指数和相关分析法,计算得到2001−2016年祁连山地区FVC和表示干旱的标准化降水蒸散发指数(standardized precipitation evaportranspiration index,SPEI),分析FVC和SPEI时空分布特征和动态变化趋势,以及二者之间的相关关系。研究表明:1)2001−2016年祁连山地区FVC整体呈增长趋势,2001年FVC最低,2011年FVC最大,季节变化明显,夏季FVC最高;空间上,祁连山地区FVC整体呈东南高西北低的分布特征,年均值为0.4522,区域差异明显,绝大部分区域FVC呈增加趋势;2)近16年,祁连山地区FVC改善的区域占77.13%,退化的区域占22.87%;FVC未来变化趋势负向特征强于正向特征,持续改善的面积为28.10%,由改善到退化的面积最大为49.23%,需要加大力度对这些区域进行关注和保护;3)祁连山地区绝大多数地区处于湿润状态,中段和东段部分地区处于轻度干旱;不同时间尺度上,年际SPEI均呈现干旱化加强趋势,总体上2001−2016年祁连山地区干旱化程度呈降低趋势,气候向好的方向发展;4)年尺度上祁连山地区SPEI与FVC呈正相关关系,季节尺度上夏季FVC对SPEI干旱程度响应最明显,春季和秋季次之,说明FVC与SPEI间相关显著性越高,响应也就越明显。
The Qilian Mountains are located in the arid and semi-arid areas of Northwest China,where the climate is dry with little precipitation;thus,the internal ecological environment is fragile.Global warming and economic development have an important impact on the regional ecological environment.The study of the temporal and spatial distribution characteristics and trends of fractional vegetation cover(FVC)and the response of FVC to drought can provide a basis for the improvement of the ecological environment and mitigation of drought impacts.Based on MOD13Q1 remote sensing and meteorological data,the spatial and temporal distribution characteristics and dynamic trends of FVC and standardized precipitation evapotranspiration index(SPEI),and the correlation between them,in the Qilian Mountains Region from 2001 to 2016 were calculated using the dimidiate pixel model,Thornthwaite method,trend analysis method,Hurst exponent,and correlation analysis method.From 2001 to 2016,the overall FVC in the Qilian Mountains showed an increasing trend.FVC was the lowest in 2001 and highest in 2011.Moreover,there were seasonal changes,and coverage was the highest in summer.From a spatial perspective,FVC in the Qilian Mountains was generally high in the southeast and low in the northwest,with an average annual value of 0.4522.Thus,there were regional differences,although FVC in most regions showed an increasing trend.During the past 16 years,77.13%of the vegetation area in the Qilian Mountains improved and 22.87%degenerated.In the future,this change will likely tend to be negative rather than positive,although 28.1%of the vegetation area in the Qilian Mountains may continuously improve.However,the future trend of 49.23%of this area is uncertain at the maximum;therefore,these areas need more focus and protection.Most areas in the Qilian Mountains were in a humid state,and some areas in the middle and eastern sections were in a mild drought.The SPEIs on the 1-,3-,6-,and 12-month scales showed a trend of increasing aridity.Overall,the degre
作者
刘佳茹
赵军
王建邦
LIU Jiaru;ZHAO Jun;WANG Jianbang(College of Geographical and Environment Science,Northwest Normal University,Lanzhou 730070,Gansu,China;College of Earth and Environmental Sciences,Lanzhou University,Lanzhou 730030,Gansu,China)
出处
《草业科学》
CAS
CSCD
北大核心
2021年第3期419-431,共13页
Pratacultural Science
基金
国家自然科学基金项目(41661084)。
关键词
植被覆盖度
标准化降水蒸散发指数
时空变化
相关性分析
祁连山地区
fractional vegetation cover
standardised precipitation evapotranspiration index
spatiotemporal variation
correlation analysis
Qilian Mountains
