نتایج جستجو برای: snow load

تعداد نتایج: 165439  

Journal: :Journal of Structural and Construction Engineering (Transactions of AIJ) 2012

2016
Noah P. Molotch David M. Barnard Sean P. Burns Thomas H. Painter

The distribution of forest cover exerts strong controls on the spatiotemporal distribution of snow accumulation and snowmelt. The physical processes that govern these controls are poorly understood given a lack of detailed measurements of snow states. In this study, we address one of many measurement gaps by using contact spectroscopy to measure snow optical grain size at high spatial resolutio...

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...

ژورنال: علوم آب و خاک 2010
آخوندعلی, علی محمد, امیری چایجان, رضا, زارع ابیانه, حمید, شریفی, محمدرضا, طبری, حسین, معروفی, صفر,

In mountainous basins, snow water equivalent is usually used to evaluate water resources related to snow. In this research, based on the observed data, the snow depth and its water equivalent was studied through application of non-linear regression, artificial neural network as well as optimization of network's parameters with genetic algorithm. To this end, the estimated values by artificial n...

2017
Christian Rixen Veronika Stoeckli

Increasing production of artificial snow in ski resorts is controversially discussed, but only few investigations have been carried out systematically to specify the environmental impacts. We measured snow depth and density from groomed ski pistes (runs) with compacted snow and their effects on ground temperatures and timing of snowmelt. We analyzed groomed pistes with and without artificial sn...

2003
GEORGE RIGGS DOROTHY K. HALL

A challenging problem in snow mapping is the discrimination of snow from clouds. Snow and clouds often have similar spectral reflectance features across the spectrum and may have similar temperatures making discrimination difficult. Data from the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard the NASA Earth Observing System (EOS) Terra spacecraft, is used to generate many geophys...

2014
Z. H. He J. Parajka F. Q. Tian G. Blöschl

Degree-day factors are widely used to estimate snowmelt runoff in operational hydrological models. Usually, they are calibrated on observed runoff, and sometimes on satellite snow cover data. In this paper, we propose a new method for estimating the snowmelt degree-day factor (DDFS) directly from MODIS snow covered area (SCA) and ground-based snow depth data without calibration. Subcatchment sn...

2009
Cheney M. SHREVE Gregory S. OKIN Thomas H. PAINTER

Snow cover in the Tibetan Plateau is highly variable in space and time and plays a key role in ecological processes of this cold-desert ecosystem. Resolution of passive microwave data is too low for regional-scale estimates of snow cover on the Tibetan Plateau, requiring an alternate data source. Optically derived snow indices allow for more accurate quantification of snow cover using higherres...

2013
Karl Rittger Thomas H. Painter Jeff Dozier

Characterization of snow is critical for understanding Earth’s water and energy cycles. Maps of snow from MODIS have seen growing use in investigations of climate, hydrology, and glaciology, but the lack of rigorous validation of different snow mapping methods compromises these studies. We examine three widely used MODIS snow products: the ‘‘binary’’ (i.e., snow yes/no) global snow maps that we...

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