Enhanced scaling effects significantly lower the ability of MODIS normalized difference snow index to estimate fractional and binary snow cover on the Tibetan Plateau

Identifying water and snow cover/glaciers (SCG) accurately is of great importance for monitoring different water resources in the Tibetan Plateau. However, discriminating between water and SCG remains a difficult task because of their similar spectral characteristic according to the physical principles of remote sensing. To efficiently distinguish different kinds of water resources automatically, here we proposed two new indices including: (i) the normalized difference water index with no SCG information (NDWIns) to extract lake water and suppress SCG: and (ii) the normalized difference snow index with no water information (NDSInw) to extract SCG and suppress lake water. Both new water and snow indices were tested in the Tibetan Plateau using Landsat series, showing that the overall accuracies of NDWIns and NDSInw were in the range of 94.6–97.0% and 94.9–97.0% in mapping the lake water from SCG and mapping the SCG from lake water, respectively. Further comparisons suggest that these new two indices improved upon the previous normalized difference snow index/modified normalized difference water index (NDSI/MNDWI) in mapping the water body and SCG. While the present study only focuses on the validation over certain areas in Tibetan Plateau, the newly proposed NDWIns and NDSInw have the potential for better monitoring the lake water and snow/glacier areas over other cold regions around the globe.

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Spatio-Temporal Variation Characteristics of Snow Depth and Snow Cover Days over the Tibetan Plateau

Water ◽

10.3390/w13030307 ◽

2021 ◽

Vol 13 (3) ◽

pp. 307

Author(s):

Chi Zhang ◽

Naixia Mou ◽

Jiqiang Niu ◽

Lingxian Zhang ◽

Feng Liu

Keyword(s):

Tibetan Plateau ◽

Snow Cover ◽

Snow Depth ◽

Feedback Effect ◽

Effect Of Temperature ◽

The Tibetan Plateau ◽

Reanalysis Dataset ◽

Spatio Temporal ◽

The Impact ◽

Main Factor

Changes in snow cover over the Tibetan Plateau (TP) have a significant impact on agriculture, hydrology, and ecological environment of surrounding areas. This study investigates the spatio-temporal pattern of snow depth (SD) and snow cover days (SCD), as well as the impact of temperature and precipitation on snow cover over TP from 1979 to 2018 by using the ERA5 reanalysis dataset, and uses the Mann–Kendall test for significance. The results indicate that (1) the average annual SD and SCD in the southern and western edge areas of TP are relatively high, reaching 10 cm and 120 d or more, respectively. (2) In the past 40 years, SD (s = 0.04 cm decade−1, p = 0.81) and SCD (s = −2.3 d decade−1, p = 0.10) over TP did not change significantly. (3) The positive feedback effect of precipitation is the main factor affecting SD, while the negative feedback effect of temperature is the main factor affecting SCD. This study improves the understanding of snow cover change and is conducive to the further study of climate change on TP.

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Assessment of MODIS-Based Fractional Snow Cover Products Over the Tibetan Plateau

IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing ◽

10.1109/jstars.2018.2879666 ◽

2019 ◽

Vol 12 (2) ◽

pp. 533-548 ◽

Cited By ~ 8

Author(s):

Shirui Hao ◽

Lingmei Jiang ◽

Jiancheng Shi ◽

Gongxue Wang ◽

Xiaojing Liu

Keyword(s):

Tibetan Plateau ◽

Snow Cover ◽

The Tibetan Plateau ◽

Fractional Snow Cover

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Review of "Evaluation of snow depth and snow-cover over the Tibetan Plateau in global reanalyses using in-situ and satellite remote sensing observations"

10.5194/tc-2019-49-rc1 ◽

2019 ◽

Author(s):

Anonymous

Keyword(s):

Remote Sensing ◽

Tibetan Plateau ◽

Snow Cover ◽

Snow Depth ◽

Satellite Remote Sensing ◽

The Tibetan Plateau

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IMPACT OF TIBETAN PLATEAU SNOW COVER ON ABRUPT INTERDECADAL PRECIPITATION CHANGE OVER THE INDOCHINA PENINSULA IN THE MID-1990S

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ◽

10.5194/isprs-archives-xlii-3-w9-57-2019 ◽

2019 ◽

Vol XLII-3/W9 ◽

pp. 57-62

Author(s):

Y. Ha ◽

Y. M. Zhu ◽

Y. J. Hu ◽

Z. Zhong

Keyword(s):

Tibetan Plateau ◽

Snow Cover ◽

Summer Precipitation ◽

Tropical Indian Ocean ◽

Western Pacific Subtropical High ◽

Precipitation Change ◽

Interdecadal Change ◽

Northwestern Pacific ◽

The Tibetan Plateau ◽

Indochina Peninsula

Abstract. Abrupt interdecadal changes in summer precipitation (May – September) over the Indochina Peninsula in the past 40 years have been investigated based on the NCEP-NCAR reanalysis product over 1979–2013 and multiple precipitation datasets. The mechanism for the abrupt change is explored. Results indicate that an abrupt interdecadal change in summer precipitation over the Indochina Peninsula occurred in the middle 1990s, and the annual mean summer precipitation during 1994–2002 increased by about 10% compared to that during 1982–1993. The most significant precipitation change occurred in the central and northern peninsula. Further analysis reveals that the interdecadal decrease in snow cover over the Tibetan Plateau in the winter and spring contributed to the summer precipitation increase over the Indochina Peninsula. The decrease in snow cover over the Tibetan Plateau actually increased the thermal contrast between the Tibetan Plateau and the tropical Indian Ocean-northwestern Pacific, leading to intensified summer monsoon over the northwestern Pacific and the South China Sea. As a result, westerly anomalies occurred from the Bay of Bengal to the northwestern Pacific, while anomalous cyclonic circulation prevailed in the upper levels above East Asia. Correspondingly, the western Pacific subtropical high weakened and shifted eastward. Under the joint effects of the above circulation patterns, the atmosphere became wetter in the Indochina Peninsula and summer precipitation increased. Results of the present study provide a theoretical basis for the prediction of long-term summer precipitation change in the Indochina Peninsula.

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