نتایج جستجو برای: snow
تعداد نتایج: 17514 فیلتر نتایج به سال:
This paper compares and integrates different strategies to characterize the variability of end-of-winter snow depth and its relationship to topography in ice-wedge polygon tundra of Arctic Alaska. Snow depth was measured using in situ snow depth probes and estimated using groundpenetrating radar (GPR) surveys and the photogrammetric detection and ranging (phodar) technique with an unmanned aeri...
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...
Runo in glacierized alpine basins results from both seasonal snow cover and glacier melt. In this paper we present a case study for an improved runo modelling of the basin Massa-Blatten, 196 km, 1447±4191 m a.s.l. Using high resolution satellite sensors, it is possible to separately map snow cover and glacier areas. From the satellite data we derive depletion curves of snow covered areas in s...
Reasonably simple yet realistic modelling schemes simulating the heat and mass balance within a snow pack are required to provide the necessary boundary conditions for meteorological and hydrological models. An improvement to a one-layer snow energy balance model (UEB, Tarboton et al., 1995) is proposed to better simulate snow surface and snow pack temperatures and, as a result, snowmelt. The m...
Tritiated water was evaluated and used for determining snow and water intake by cattle. This method yielded results comparable to those obtained via simultaneous gravimetric measurement of snow and liquid water intake after adjustments were made for preformed and metabolic water from feed; the correlation coefficient was .96 and the standard error of the estimate was +/- 1.28 kg/day, or +/- 5.8...
Remote sensing of light-absorbing particles (LAPs), or dark colored impurities, such as black carbon (BC) and dust on snow, is a key remaining challenge in cryospheric surface characterization and application to snow, ice, and climate models. We present a quantitative data set of in situ snow reflectance, measured and modeled albedo, and BC and trace element concentrations from clean to heavily...
Within the context of developing data inversion and assimilation techniques for C-band backscatter over sea ice, snow physical models may be used to drive backscatter models for comparison and optimization with satellite observations. Such modeling has the potential to enhance understanding of snow on sea-ice properties required for unambiguous interpretation of active microwave imagery. An end...
Snow aging causes reflectance to vary significantly on timescales of days. This variability influences the strength of snow-albedo feedback, and can affect the timing of snowmelt. However, climate models have yet to incorporate important controls on snow aging and albedo evolution. We develop a physically-based model that predicts evolution of dry, pure-snow specific surface area, and apply asp...
We present Ku-band backscatter signatures of snow for applications to global snow monitoring with NASA Scatterometer (NSCAT) on the ADEOS satellite and the SeaWinds scatterometer on the QuikSCAT satellite. We carried out the 1999 Alaska Snow Experiment to study the relation between Ku-band backscatter and snow physical properties. The experimental results are applied to interpret backscatter da...
It is difficult and time consuming to use traditional measurement methods to estimate the physical properties of snow. However, the emergence of hyperspectral imagery for estimating the physical properties of snow provides a powerful tool. Snow albedo, grain size, and temperature are important factors for evaluating the surface energy balance. Using the spectrum-reflection curves of the differe...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید