نتایج جستجو برای: snow cover

تعداد نتایج: 124383  

2016
Daniel Kępski Marek Błaś Mieczysław Sobik Żaneta Polkowska Katarzyna Grudzińska

Main aim of the work assumed recognition of physicochemical changes in snowpack occurring during the melting period. Properties of snow cover had been identified at two sites in Western Sudetes mountains (860 and 1228 m asl) in SW Poland since the end of January, and monitored until the disappearance of snow in late Spring. Snow pit measurements and sample collection at both sites were made fol...

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...

2014
Parviz Rezaei

Original scientific paper Determining snowmelt runoff share of watershed basins with snow and wet snow regimes is one of the main concerns of the experts in water resources field, assessment of which has been done so far with difficulties and high rate of error due to lack of snow survey and weather stations in highlands of basin and use of traditional surveying methods. Lack of integrated mana...

2004
Cezar Kongoli Ralph Ferraro

The estimation of snow water equivalent (SWE) from passive microwave sensors remains a formidable challenge primarily due to the non-unique nature of the microwave scattering signatures over snow cover surfaces. Ideally, there is a straightforward relationship between the volume of snow crystals present in the snow pack, and hence, SWE or snow depth, and the degree of microwave scattering by ic...

2010
J. Parajka M. Pepe A. Rampini S. Rossi G. Blöschl

The objective of this study is to propose and evaluate a method for snow cover mapping during clouds using the daily MODIS/Terra snow cover product. The proposed SNOWL approach is based on reclassifying pixels assigned as clouds to snow or land according to their relative position to the regional snow-line elevation. The accuracy of the SNOWL approach is evaluated over Austria, using daily snow...

2010
J. W. POMEROY

As demonstrated in the previous chapter, snow interacts strongly with the global climate system, both influencing and forming as a result of this system. The following chapters discuss the interaction of snow with the chemical and biological systems. This chapter discusses the physical properties of snow as the habitat and regulator of the snow ecosystem. In this sense, the physical snow cover ...

2004
N. P. Molotch S. R. Fassnacht R. C. Bales S. R. Helfrich

The temporal and spatial continuity of spatially distributed estimates of snow-covered area (SCA) are limited by the availability of cloud-free satellite imagery; this also affects spatial estimates of snow water equivalent (SWE), as SCA can be used to define the extent of snow telemetry (SNOTEL) point SWE interpolation. In order to extend the continuity of these estimates in time and space to ...

2001
JOSEPH P. McFADDEN GLEN E. LISTON MATTHEW STURM ROGER A. PIELKE Joseph P. McFadden

In arctic tundra, where wind transport of snow is common, shrubs can significantly modify the distribution and physical characteristics of the snow cover. We examined interactions between shrubs and snow by measuring snow depths along three 1-km transects in arctic Alaska and then measuring plant canopy characteristics at the same locations during the following growing season. Snow depths corre...

2008
Jessica D. Lundquist Fred Lott

[1] Small, self-recording temperature sensors can be deployed quickly and inexpensively to monitor spatial and temporal patterns of snow accumulation and melt in complex environments. Burying these sensors slightly below the soil surface provides a record of the presence or absence of snow cover because near-surface soil temperatures only experience diurnal temperature oscillations when they ar...

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