The albedo of snow for partially cloudy skies

Choudhury, Bhaskar J.; Chang, A. T. C.

doi:10.1007/bf00121380

Cited by 63 publications

(20 citation statements)

References 29 publications

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“…Owing to the selective absorption in the near infra-red, the LI-COR pyranometer could possibly overestimate the reflected radiation. Albedos calculated in this study are substantially lower than those postulated by Sellers (1 969, or the values reported by Choudhury (198 l), Choudhury and Chang (1981a, 1981b and Warren (1982). This has the effect of significantly increasing the net solar radiation, even after new snow has fallen.…”

Section: Radiation Measurementcontrasting

confidence: 77%

Automated system for measuring snow surface energy balance components in mountainous terrain

Sauter¹,

McDonnell

1994

Hydrological Processes

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The ability to continually monitor several meteorological parameters is needed to estimate snow surface energy balance components in mountainous terrain. In remote mountainous locations, limited accessibility and extreme weather conditions limit the use of delicate meteorological instrumentation. Robust instrumentation and radio telemetry are often needed to measure snow surface energy exchanges. This study examined the practicality and effectiveness of robust instrumentation in estimating radiative and turbulent exchanges in the forested Bear River Mountains of northern Utah. Measurement of reflected shortwave radiation was problematic due to possible selective absorption in the infra-red range. This resulted in overestimates of reflected shortwave radiation and decreased estimates of now surface albedo. During high snowfall, the pyranometer and net radiometer were occasionally covered with snow, resulting in inaccurate radiation measurements. Snow typically melted from instrument surfaces in less than one day under full sun. A relative humidity measurement accuracy of f 4% may have resulted in a possible error of 20% in the calculation of vapour pressure. Snow depth measurement with an acoustical sensor was affected by new or blowing snow, which resulted in inaccurate snow depth measurement 16.2% of the time. The longest period without a valid snow depth measurement was 19.5 hours. A new snow temperature thermocouple ladder was designed and constructed and provided accurate within-pack temperature measurements throughout the pre-melt and melt season.

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Section: Radiation Measurementcontrasting

confidence: 77%

Automated system for measuring snow surface energy balance components in mountainous terrain

Sauter¹,

McDonnell

1994

Hydrological Processes

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“…But, as snow ages and the number of melt/freeze events to which it is subjected increases, the specular reflection component increases especially in the forward direction. Furthermore, the specular reflection component increases with solar zenith angle (SZA) [Salomonson and Marlatt, 1968;Choudhury and Chang, 1981;Dozier et al, 1981]. As noted by Steffen [1987], fresh snow with a grain radius of 0.15 mm is nearly a Lambertian (isotropic) target, but the anisotropic nature of snow reflectance increases with increasing grain size.…”

Section: Albedo Of Snowmentioning

confidence: 98%

“…In addition to the natural variability of snow albedo due to metamorphosis, there is evidence that carbon from industrial pollution or soot, produced in nonpolar areas, may cause a reduction in the albedo of fresh snow and thus increase the amount of solar radiation that is absorbed at the surface [Chylek et al, 1983;Warren andWiscombe, 1980, 1985]. The magnitude of decrease in snow albedo caused by soot may be equal to that of the atmospheric effects of Arctic haze, in which less shortwave radiation is absorbed at the surface because of the haze [Clarke and Noone, 1985].…”

Section: Albedo Of Snowmentioning

confidence: 99%

Assessment of polar climate change using satellite technology

Hall¹

1988

Reviews of Geophysics

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Results from general circulation models (GCMs) have indicated that a predicted climate warming resulting from an increase in atmospheric carbon dioxide (CO 2) will be amplified in the polar regions and that temperature increases in the polar regions will be several times greater than the global average. Some GCMs predict a 4ø-5øC average air temperature increase in the Arctic by the middle of the next century. Evidence from the polar regions indicates that a warming in the cryosphere may already be in progress. A 2ø-4øC rise in permafrost temperature, measured in northern Alaska, is believed to have occurred during the last 100 years. In addition, many small valley glaciers and ice caps have experienced retreat and appear to have contributed up to 50% to the observed rise (10-15 cm) in sea level during the last century. Other work shows that increased snowfall which can be associated with warmer temperatures has caused thickening of some Alaskan glaciers. Though a decrease in snow and sea ice cover would be a likely consequence of global warming, a sustained decrease in global snow and sea ice extent has not been found from analysis of more than 20 years of image data (1.1-km pixel resolution) from National Oceanic and Atmospheric Administration meteorological satellites and more than 7 years of scanning multichannel microwave radiometer snow data (30-km pixel resolution) on the Nimbus 7 satellite. Snow and sea ice are sensitive to atmospheric temperature changes because of their large surface to volume ratio. While measurements of snow and sea ice extent, snow depth, and sea ice concentration are possible using visible, near-infrared, or microwave sensors on satellites, it is not feasible to measure the mass balance of the ice sheets with these sensors directly. Estimates by glaciologists show that the Greenland Ice Sheet is in approximate equilibrium and that the Antarctic Ice Sheet has a positive mass balance. Satellite radar altimetry (and in the future, laser altimetry) is a promising technique for measuring the surface elevation of ice sheets. Satellite-borne laser altimetry in conjunction with imagery on ice sheet extent will permit direct measurements of changes in mass balance of the ice sheets through time. The terminus positions and ablation area boundaries of valley glaciers are indicative of glacier mass balance; these can be studied using visible and near-infrared data from the Landsat satellite series and data from the French Systeme Probatoire d'Observation de la Terre (SPOT) satellite and synthetic aperture radar data. Lake ice freeze-up and breakup dates are sensitive to regional air temperature and may also be good indicators of climate trends. Monitoring the onset of lake freeze-up and breakup dates is feasible with radar and visible image data. The very important role of snow and ice in global processes is being highlighted as large-scale, satellite-derived geophysical data sets have become available and are beginning to be used as realistic input to GCMs. This paper is not subject to U.S. co...

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“…Thus, clouds as well as snow-ice surfaces absorb selectively in the near-infrared. This implies that the integrated surface albedo under overcast conditions exceeds the clear-sky value (Grenfell and Maykut 1977;Grenfell and Perovich 1984;Choudhury and Chang 1981;Shine and Henderson-Sellers 1985). The importance of the surface is underscored by recent observational findings indicating that interannual variations of snow cover are, to a large extent, responsible for the interannual variability of surface air temperature over northern land areas, especially during spring (Groisman et al 1994).…”

Section: Nsa-aao Primary Scientific Focus: Highlatitude Phenomenamentioning

confidence: 99%

Review of Science Issues, Deployment Strategy, and Status for the ARM North Slope of Alaska–Adjacent Arctic Ocean Climate Research Site

et al. 1999

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Recent climate modeling results point to the Arctic as a region that is particularly sensitive to global climate change. The Arctic warming predicted by the models to result from the expected doubling of atmospheric carbon dioxide is two to three times the predicted mean global warming, and considerably greater than the warming predicted for the Antarctic. The North Slope of Alaska-Adjacent Arctic Ocean (NSA-AAO) Cloud and Radiation Testbed (CART) site of the Atmospheric Radiation Measurement (ARM) Program is designed to collect data on temperature-ice-albedo and water vapor-cloud-radiation feedbacks, which are believed to be important to the predicted enhanced warming in the Arctic. The most important scientific issues of Arctic, as well as global, significance to be addressed at the NSA-AAO CART site are discussed, and a brief overview of the current approach toward, and status of, site development is provided. ARM radiometric and remote sensing instrumentation is already deployed and taking data in the perennial Arctic ice pack as part of the SHEBA (Surface Heat Budget of the Arctic Ocean) experiment. In parallel with ARM's participation in SHEBA, the NSA-AAO facility near Barrow was formally dedicated on 1 July 1997 and began routine data collection early in 1998. This schedule permits the U.S. Department of Energy's ARM Program, NASA's Arctic Cloud program, and the SHEBA program (funded primarily by the National Science Foundation and the Office of Naval Research) to be mutually supportive. In addition, location of the NSA-AAO Barrow facility on National Oceanic and Atmospheric Administration land immediately adjacent to its Climate Monitoring and Diagnostic Laboratory Barrow Observatory includes NOAA in this major interagency Arctic collaboration.

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The albedo of snow for partially cloudy skies

Cited by 63 publications

References 29 publications

Automated system for measuring snow surface energy balance components in mountainous terrain

Automated system for measuring snow surface energy balance components in mountainous terrain

Assessment of polar climate change using satellite technology

Review of Science Issues, Deployment Strategy, and Status for the ARM North Slope of Alaska–Adjacent Arctic Ocean Climate Research Site

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