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Arid Land Geography ›› 2022, Vol. 45 ›› Issue (1): 37-45.doi: 10.12118/j.issn.1000–6060.2021.029

• Hydrology and Water Resources • Previous Articles     Next Articles

Change of ice phenology in the Sayram Lake from 2000 to 2019

QIN Qiyong1,2,3(),LI Xuemei1,2,3(),ZHANG Bo1,2,3,LI Chao1,2,3,SUN Tianyao1,2,3   

  1. 1. Faculty of Geomatics, Lanzhou Jiaotong University, Lanzhou 730070, Gansu, China
    2. Gansu Provincial Engineering Laboratory for National Geographic State Monitoring, Lanzhou 730070, Gansu, China
    3. National-Local Joint Engineering Research Center of Technologies and Applications for National Geographic State Monitoring, Lanzhou 730070, Gansu, China
  • Received:2021-01-12 Revised:2021-04-25 Online:2022-01-25 Published:2022-01-21
  • Contact: Xuemei LI E-mail:2945030583@qq.com;lixuemei@lzjtu.edu.cn

Abstract:

Lake ice phenology is a sensitive indicator of climate change. To clarify the changes in ice characteristics and influencing factors of lakes in Tianshan Mountains, which has alpine characteristics, Sayram Lake of Xinjiang in China is taken as the object of study. Sayram Lake is located in a closed alpine basin of brackish water. With its unique geographical location, the lake’s evolution and ice conditions are rarely influenced by human activities, and it can be an ideal research area for lake ice phenology in this region. This study conducted an analysis mainly based on MODIS, Chinese lake data, and meteorological data to reveal the phenological characteristics of lake ice on Sayram Lake during 2000—2019 by applying threshold, trend analysis, and other methods. We also identified the climatic factors that have influenced lake ice phenology over time and draw some conclusions. Results are summarized as follows: (1) Freeze-up start (FUS), freeze-up end (FUE), break-up start (BUS), and break-up end (BUE) on Sayram Lake usually occurred on November 2, January 18, April 26, and May 17, respectively. The average rates of FUE, BUS, and BUE were -0.25 d·a-1, -0.03 d·a-1, and -0.44 d·a-1, respectively. The average complete ice duration (CID, between FUE and BUS) and the average ice duration (ID, between FUS and BUE) were 99 d and 196 d, respectively. (2) In the past 20 years, the BUS and BUE of Sayram Lake showed an earlier trend, and the FUE also showed an earlier trend, which was related to the decreasing trend of the average temperature in January. The BUS and BUE of Sayram Lake are related to the rising trend of average temperature in April to May and May to June. The ID was shortened, whereas the CID was prolonged. (3) Sayram Lake can be characterized by similar spatial patterns in both freeze-up (FU) and break-up (BU) processes, as parts of the surface that freeze earlier start to melt first. A more complex lake edge corresponds to an earlier start of the freezing time. Generally, freeze begins from the lakeshore and then gradually expands to the center of the lake until the lake is completely frozen. The ice begins to break in late April, and thawing begins from the northeastern lake shore. The lake ice from the shore moves gradually to the center of the slow melting and is completely melted by mid-May. Compared with the freezing process, melting on Sayram Lake is faster, lasting only 40 d, which is distinctly different from other lakes on the Tibetan Plateau. (4) The variations of phenology and evolution of the Sayram Lake ice are the results of local and climatic factors. The temperature, accumulated negative accumulated temperature, lake morphology factors, lake area, and shape of the shoreline are the main factors that affect the phenology of lake ice. However, the effect of lake salinity and geological structure on lake ice evolution cannot be ignored. This study on the phenological characteristics of lake ice on Sayram Lake can provide supplemental data for arid/semi-arid areas that lack data and provide more accurate parameter indicators and scientific basis for studying climate change in Sayram Lake and even Tianshan.

Key words: lake ice, phenology, MODIS, Sayram Lake, climate change