نتایج جستجو برای: snow cover area

تعداد نتایج: 691239  

2007
Miia Eskelinen Sari Metsämäki

The objective of this work is to evaluate the use of the Medium Resolution Imaging Spectrometer (MERIS) data for seasonal snow cover monitoring specifically in the boreal forest belt. For this purpose, we tuned an existing method for fractional snow cover mapping in order to produce snow maps from MERIS imagery. The method was originally developed at the Finnish Environment Institute (SYKE), wh...

2017
Gao Jie

Snow is an important research interest in international cryosphere research. In China, cold region account for 43% of the total area (Yang et al., 2000). The area of stable snow where snow cover duration is greater than 60 days is approximately 420×104km2. In West China, the recharge to spring freshet from winter snow is a necessary regulation for spring drought (Qin et al., 2006). However, lar...

Journal: :جغرافیا و مخاطرات محیطی 0
محمد صادق کیخسروی کیانی سید ابوالفضل مسعودیان

1. introduction glaciers and snow covers in the mountains play an important role in the water budget of many areas of the world (ramage and isacks, 2003). in high altitudes and mountainous regions, snowmelt is a great contributor to the yearly runoff. the snow melt supplies 1/6 of people's needed water but due to global warming these glaciers may be at risk (barnett, et al. 2005). for the regio...

2007
Zhaoxia Pu Li Xu Vincent V. Salomonson

[1] Seasonal variations of snow cover fraction (SFC) over the Tibet Plateau (TP) are examined using the data acquired from the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra spacecraft. In this study, we first evaluate the accuracy of the MODIS high-resolution snow cover data by comparing the data with in-situ Chinese snow observations. Results show that overall accuracy of ...

2008
Linda Valenti David Small Erich Meier

ABSTRACT A method has been developed to apply multi-temporal Advanced Synthetic Aperture Radar (ENVISAT/ASAR, C-Band) images to snow cover monitoring and mapping in mountainous areas. A multi-temporal dataset that includes sequences of ascending and descending ASAR wide swath and beam mode IS2 scenes acquired over Switzerland was investigated. The images were geometrically corrected to remove r...

Journal: :Remote Sensing 2017
Wenfang Xu Hanqing Ma Donghai Wu Wenping Yuan

Snow cover plays a crucial role in surface hydrology and energy balance, especially in the Qinghai-Tibetan Plateau (QTP). This study used 12 years (2000–2011) of ground-observed snow depth at 87 meteorological stations to assess and verify the accuracy of the daily cloud-free snow-cover product from the Moderate Resolution Imaging Spectroradiometer (MODIS) over the QTP. On average, the daily cl...

2007
Baolin Li A-Xing Zhu Chenghu Zhou Yichi Zhang Tao Pei Chengzhi Qin

Snow cover depletion curves are required for several water management applications of snow hydrology and are often difficult to obtain automatically using optical remote sensing data owing to both frequent cloud cover and temporary snow cover. This study develops a methodology to produce accurate snow cover depletion curves automatically using high temporal resolution optical remote sensing dat...

1997
ZONG-LIANG YANG ROBERT E. DICKINSON ALAN ROBOCK

Snow cover is one of the most important variables affecting agriculture, hydrology, and climate, but detailed measurements are not widely available. Therefore, the effectiveness and validity of snow schemes in general circulation models have been difficult to assess. Using long-term snow cover data from the former Soviet Union, this paper focuses on the validation of the snow submodel in the Bi...

2004
Loew

Remote sensing methods to derive snow properties using both optical and SAR data are presented. The assimilation of the remote sensing products in the water balance and rainfall-runoff model LARSIM is demonstrated. The flood forecast centre in Karlsruhe applies LARSIM for the operational runoff forecast of the Neckar in the South West of Germany. A fully automatic algorithm to derive snow cover...

Journal: :Remote Sensing 2017
Rafael Pimentel Javier Herrero María José Polo

Mediterranean mountainous regions constitute a climate change hotspot where snow plays a crucial role in water resources. The characteristic snow-patched distribution over these areas makes spatial resolution the limiting factor for its correct representation. This work assesses the estimation of snow cover area and the contribution of the patchy areas to the seasonal and annual regime of the s...

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