Variations of Lake Ice Phenology on the Tibetan Plateau From 2001 to 2017 Based on MODIS Data
Variations of Lake Ice Phenology on the Tibetan Plateau From 2001 to 2017 Based on MODIS Data
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DOI：
10.1029/2018jd028993
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发表时间：
2019-01-27
影响因子：
4.4
通讯作者：
Lee, Hoonyol
中科院分区：
文献类型：
--
作者：
Cai, Yu;Ke, Chang-Qing;Lee, Hoonyol
湖冰是气候变化的有力指标。通过间隙填充去除云后，中分辨率成像光谱辐射计 2000 年至 2017 年每日积雪产品中包含的信息的可用性可以大大提高。基于开放水域像素数的阈值用于提取青藏高原（TP）58个湖泊的结冰开始和解冻结束日期；还选择了 18 个湖泊来提取结冰结束和解体开始日期。根据冻结和破裂日期进一步计算湖冰持续时间。青藏高原湖泊于10月下旬开始结冰，次年1月中旬所有湖泊开始结冰期。 3月下旬，部分湖泊开始解冻，7月初所有湖泊结束冰盖期。一般来说，内高原北部的湖泊比内高原南部的湖泊结冰日期早，解冻日期晚（即冰盖持续时间长）。 17年来，58个湖泊的平均冰盖持续时间为157.78天，其中18个（31%）湖泊的平均冰盖延伸率为1.11天/年，40个（69%）的湖泊平均冰盖缩短率为0.80天/年。地理位置和气候条件决定了湖冰物候尤其是破裂日期的空间异质性，而物理化学特征主要影响本研究中湖冰的结冰日期。冰盖持续时间受气候和湖泊特定理化因素的影响，可以反映青藏高原湖泊的气候和环境变化。
Lake ice is a robust indicator of climate change. The availability of information contained in Moderate Resolution Imaging Spectroradiometer daily snow products from 2000 to 2017 could be greatly improved after cloud removal by gap filling. Thresholds based on open water pixel numbers are used to extract the freezeup start and breakup end dates for 58 lakes on the Tibetan Plateau (TP); 18 lakes are also selected to extract the freezeup end and breakup start dates. The lake ice durations are further calculated based on freezeup and breakup dates. Lakes on the TP begin to freezeup in late October and all the lakes start the ice cover period in mid-January of the following year. In late March, some lakes begin to break up, and all the lakes end the ice cover period in early July. Generally, the lakes in the northern Inner-TP have earlier freezeup dates and later breakup dates (i.e., longer ice cover durations) than those in the southern Inner-TP. Over 17years, the mean ice cover duration of 58 lakes is 157.78days, 18 (31%) lakes have a mean extending rate of 1.11day/year, and 40 (69%) lakes have a mean shortening rate of 0.80day/year. Geographical location and climate conditions determine the spatial heterogeneity of the lake ice phenology, especially the ones of breakup dates, while the physico-chemical characteristics mainly affect the freezeup dates of the lake ice in this study. Ice cover duration is affected by both climatic and lake specific physico-chemical factors, which can reflect the climatic and environmental change for lakes on the TP.