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干旱区地理 ›› 2021, Vol. 44 ›› Issue (1): 15-26.doi: 10.12118/j.issn.1000–6060.2021.01.02

• 气候与水文 • 上一篇    下一篇

2002—2018年叶尔羌河流域积雪时空变化研究

易颖1,2(),刘时银1,2(),朱钰1,2,吴坤鹏1,2   

  1. 1.云南大学国际河流与生态安全研究院,云南 昆明 650500
    2.云南省国际河流与跨境生态重点实验室,云南 昆明 650500
  • 收稿日期:2020-03-24 修回日期:2020-10-09 出版日期:2021-01-25 发布日期:2021-03-09
  • 通讯作者: 刘时银
  • 作者简介:易颖(1996-),女,硕士研究生,研究方向为积雪变化遥感研究. E-mail: yingyi@mail.ynu.edu.cn
  • 基金资助:
    国家自然科学基金国际合作项目(41761144075);第二次青藏科考项目(2019QZKK0208);云南大学人才项目(YJRC3201702);云南大学第十一届研究生科研创新项目(2019225)

Spatiotemporal variation of snow cover in the Yarkant River Basin during 2002—2018

YI Ying1,2(),LIU Shiyin1,2(),ZHU Yu1,2,WU Kunpeng1,2   

  1. 1. Yunnan Key Laboratory of International Rivers and Transboundary Eco-security, Kunming 650500, Yunnan, China
    2. Institute of International Rivers and Eco-Security Yunnan University, Kunming 650500, Yunnan, China
  • Received:2020-03-24 Revised:2020-10-09 Online:2021-01-25 Published:2021-03-09
  • Contact: Shiyin LIU

摘要:

积雪是冰冻圈中较为活跃的因子,对气候环境变化敏感,其变化影响着全球气候和水文的变化。积雪覆盖日数(SCD)、降雪开始时间(SCOD)和融雪开始时间(SCMD)是影响地表物质和能量平衡的主要因素。使用MODIS无云积雪产品提取了叶尔羌河流域2002年7月—2018年6月逐日积雪覆盖率(SCP),基于像元计算了SCD、SCOD和SCMD,系统地分析了其空间分布与变化特征,并探讨了其变化的原因及积雪面积的异常变化与ENSO的联系。结果表明:(1) 研究时段内,流域的积雪覆盖面积呈微弱减少趋势,与气温呈显著负相关,与降水呈显著正相关;2002—2018年,SCP随海拔的升高呈明显的线性增加趋势(R2=0.92、P<0.01));各海拔高度带最大SCP出现的月份大致随海拔的上升往后推迟,最小SCP出现月份无显著变化(集中在8月),海拔4000 m以下,春季的SCP小于冬季,海拔4000 m以上,春季的SCP大于冬季。(2) SCD、SCOD和SCMD有明显的海拔梯度,在流域内,从东北至西南,呈现出SCD增加,SCOD提前,SCMD推迟的特征;变化趋势上,流域91.9%的区域SCD表现为减少,65.6%的区域SCOD有往后推迟的趋势,77.4%的区域SCMD表现出提前的趋势。(3) 2006、2008年和2017年积雪覆盖面积异常偏大,而在2010年则异常偏小,其原因可能是ENSO影响了积雪的变化。(4) 以喀喇昆仑为主的高海拔地区,包括帕米尔高原东部的部分地区,其SCD、SCOD和SCMD分别表现出增加、提前和推迟的趋势,这种变化与其春秋温度的持续走低以及降水量的增加有关。

关键词: 叶尔羌河流域, 积雪覆盖日数, 降雪开始时间, 融雪开始时间

Abstract:

Snow cover is one of the active elements in the cryosphere sensitive to climate changes. Its change can affect the global climate and hydrology changes, and its surface mass and energy balance are affected by the snow-covered days (SCD), snow cover onset dates (SCOD), and snow cover melting dates (SCMD). In this study, we employed the MODIS daily cloud-free snow cover product to calculate variations of snow cover percentage (SCP), SCD, SCOD, and SCMD from July 2002 to June 2018 in the Yarkant River Basin, south Xinjiang, China and then analyzed their distribution and spatiotemporal variations. We discussed the cause of the variation and the relation between the abnormal change of snow cover and ENSO. We found the following results: (1) In the study period, the snow cover area exhibited a slight decrease trend and had a significant negative correlation with temperature and a positive correlation with precipitation. SCP showed a clear linear increase trend with increasing altitude (R²=0.92, P<0.01). When the maximum SCP appears in each altitude zone, the month is generally delayed with the rise in altitude. In contrast, when the minimum SCP appears, the month has no obvious change with altitude (concentrated in August). SCP in spring is less than that in winter when below the 4000 m altitude. On the other hand, SCP in spring is greater than that in winter when above the 4000 m altitude. (2) Clear elevation gradients were found for SCD, SCOD, and SCMD. The spatial distributions of SCD, SCOD, and SCMD are gradually increased, delayed, and advanced, respectively, in a northeast-to-southwest direction in the basin. In the basin, from 2002 to 2018, SCD decreased to 91.9%, SCOD delayed to 65.6%, and SCMD advanced to 77.4%. (3) In 2006, 2008, and 2017, the snow cover area was abnormally large, whereas, in 2010, it was abnormally small, which may be affected by ENSO. (4) High mountains concentrated along the Karakoram, including Parts of the eastern Pamir Plateau, experienced a lengthened SCD, an advanced SCOD, and a delayed SCMD related to the continuous low temperature and the increase of precipitation in spring and autumn.

Key words: Yarkant River Basin, snow covered days, snow cover onset dates, snow cover melting dates