基于MODIS数据青海湖流域内积雪和湖冰物候变化研究  

Study on the Phenological Changes of Snow and Lake Ice in Qinghai Lake Basin based on MODIS Data

作　　者：沈姣姣 沈言龙 欧阳志棋 郭慧 王晓艳[1] SHEN Jiaojiao;SHEN Yanong;OUYANG Zhiqi;GUO Hui;WANG Xiaoyan(College of Earth and Environmental Sciences,Lanzhou University,Lanzhou 730000,Gansu,China)

机构地区：[1]兰州大学资源环境学院,甘肃兰州730000

出　　处：《高原气象》2024年第5期1177-1189,共13页Plateau Meteorology

基　　金：国家自然科学基金项目(42271373);中国科学院地理科学与资源研究所资源与环境信息系统国家重点实验室开放基金项目“2001-2018年中国东北地区积雪物候变化及其对气候的响应”。

摘　　要：物候变化对气候响应和生态环境方面的研究具有重要意义。本文基于近20年的MODISV6积雪产品和反射率产品,分别获取了青海湖流域的积雪和湖冰物候,并分析了二者的空间分布特征。在此基础上,采用Theil-Sen Median和一元线性回归法分析了积雪物候与湖冰物候的变化趋势,以及低海拔区域内二者的相关关系。结果表明:(1)青海湖湖冰开始冻结日期、开始消融日期和湖冰存在期分别在321~389d、425~464d和0~174d。整体上,开始冻结日期和开始消融日期均呈推迟趋势,推迟率分别为0.3 d·a^(-1)和0.2 d·a^(-1);湖冰存在期则呈缩短趋势,缩短率为0.6 d·a^(-1)。湖冰物候与经度具有显著相关性,湖面自东向西,湖冰开始冻结日期推后、开始消融日期提前、湖冰存在期缩短。(2)青海湖流域积雪初日、积雪终日和积雪日数分别在275~404d、353~484d和3~209d。其中积雪初日和积雪终日整体上分别呈提前趋势和推迟趋势,变化率分别为0.8d·a^(-1)和0.11d·a^(-1);积雪日数呈增长趋势,增长率为0.6d·a^(-1)。积雪物候与海拔密切相关,随着海拔的增加,积雪初日提前、积雪终日推迟、积雪日数增加。(3)冬季负积温和气温是影响湖冰物候的重要因素。冬季负积温和气温升高会导致湖冰开始冻结日期推迟、湖冰开始消融日期提前、湖冰存在期缩短。对于积雪物候,积雪日数与气温之间呈显著的负相关关系,气温下降,积雪日数增加。(4)低海拔流域内部分积雪与湖冰物候参数之间存有潜在联系。积雪初日与湖冰开始冻结日期之间具有较为显著的负相关关系,相关性系数为-0.404。而积雪作为湖面保温层,积雪日数的增加也会很大程度上减缓湖冰消融速度,致使湖冰消融日期推迟,因此二者呈一定正相关关系,相关性系数为0.349。本研究所揭示的流域内生态系统变化规律,对当地生态系统具有积极意义,可以为青海湖Phenological changes are of great significance to the study of climate response and ecological environment.Based on the MODIS V6 snow product and reflectivity product in the past 20 years,the snow and lake ice phenology in the Qinghai Lake Basin were obtained,and the spatial distribution characteristics of the two were analyzed.On this basis,Theil-Sen Median method and linear regression method were used to analyze the variation trend of snow phenology and lake ice phenology,as well as the correlation between them in low altitude areas.The results show that:(1)Freeze-up start,Break-up start and Exist Duration of lake ice in Qinghai Lake are in the range of 321~389 d,425~464 d and 0~174 d,respectively.On the whole,Freeze-up start and Break-up start of lake ice were delayed,and the delay rates were 0.3 d·a^(-1) and 0.2 d·a^(-1),respectively.Exist Duration of lake ice showed a shortening trend,with a shortening rate of 0.6 d·a^(-1).There is a significant correlation between lake ice phenology and longitude.From east to west,Freeze-up start is postponed,Break-up start is advanced,and Exist Duration of lake ice is shortened.(2)Start of snow cover days,End of snow cover days and Snow cover days in Qinghai Lake Basin are distributed in the range of 275~404 d,353~484 d and 3~209 d,respectively.Among them,start of snow cover days and End of snow cover days showed an early trend and a delayed trend respectively,and the change rates were 0.8 d·a^(-1) and 0.11 d·a^(-1) respectively.Snow cover days showed an increasing trend,with a growth rate of 0.6 d·a^(-1).Snow phenology is closely related to altitude.With the increase of altitude,start of snow cover days is advanced,End of snow cover days is delayed,and Snow cover days increases.(3)Air temperature and negative accumulated temperature in winter are important factors affecting lake ice phenology.With the increase of temperature and negative accumulated temperature in winter,Freeze-up start will be delayed,Break-up start will be advanced,and Exist Duration of lake ice w

关 键 词：青海湖流域 湖冰 积雪 物候 

分 类 号：P466[天文地球—大气科学及气象学]