scholarly journals Some Effects of Multiple Scattering on the Distribution of Solar Radiation in Snow and Ice

1972 ◽  
Vol 11 (63) ◽  
pp. 357-368 ◽  
Author(s):  
Bruce R. Barkstrom
Keyword(s):  
Solar Radiation ◽  
Multiple Scattering ◽  
Specular Reflection ◽  
Scattering Problem ◽  
Solar Flux ◽  
Isotropic Scattering ◽  
Solar Altitude ◽  
Exponential Decrease ◽  
The Antarctic ◽  
Upward Flux

AbstractMultiple scattering of the solar flux in snow and “bubbly” ice can account for the variable albedo, the non-specular reflection, the non-exponential flux decrease near the surface, and the large upward flux within the medium. The scattering problem has been formulated and solved exactly, assuming isotropic scattering in a plane-parallel, semi-infinite, grey medium. The solution shows a non-exponential flux decrease near the surface and an exponential decrease deep in the medium. For such a medium, the albedo will increase with decreasing solar altitude in a manner which agrees to within one per cent of observed snow albedos in the Antarctic.

scholarly journals Some Effects of Multiple Scattering on the Distribution of Solar Radiation in Snow and Ice

1972 ◽  
Vol 11 (63) ◽  
pp. 357-368 ◽  
Author(s):  
Bruce R. Barkstrom
Keyword(s):  
Solar Radiation ◽  
Multiple Scattering ◽  
Specular Reflection ◽  
Scattering Problem ◽  
Solar Flux ◽  
Isotropic Scattering ◽  
Solar Altitude ◽  
Exponential Decrease ◽  
The Antarctic ◽  
Upward Flux

AbstractMultiple scattering of the solar flux in snow and “bubbly” ice can account for the variable albedo, the non-specular reflection, the non-exponential flux decrease near the surface, and the large upward flux within the medium. The scattering problem has been formulated and solved exactly, assuming isotropic scattering in a plane-parallel, semi-infinite, grey medium. The solution shows a non-exponential flux decrease near the surface and an exponential decrease deep in the medium. For such a medium, the albedo will increase with decreasing solar altitude in a manner which agrees to within one per cent of observed snow albedos in the Antarctic.

Diurnal albedo variation of black spruce and sphagnum–sedge bogs

1976 ◽  
Vol 6 (3) ◽  
pp. 247-252 ◽  
Author(s):  
Erwin R. Berglund ◽  
Arnett C. Mace Jr.
Keyword(s):  
Solar Radiation ◽  
Black Spruce ◽  
Specular Reflection ◽  
Radiation Quality ◽  
Surface Flattening ◽  
Solar Altitude ◽  
Space And Time ◽  
Time Variations ◽  
Dominant Influence

Diurnal albedo relationships were determined for black spruce (Piceamariana (Mill.) B.S.P.) and sphagnum–sedge bogs in northern Minnesota. Two opposing, cart-mounted, Kipp and Zonen pyranometers traversed a tramway to integrate space and time variations of incoming and reflected solar radiation (waveband 0.3–3.0 microns (μ)).The black spruce stand's diurnal albedo was parabolic. Albedo increased with solar altitude to a maximum at 1200 h (7–8%) and then decreased. Greatest within-season variation occurred during June and September. Canopy roughness was the dominant influence on albedo variation and differences.The sphagnum–sedge type diurnal albedo was M-shaped. A minimum albedo between two maxima occurred at 1200 h. Albedos increased from the 1200-h minimum to each maxima as a result of reported surface 'flattening' effects, increased specular reflection, and changes in solar radiation quality. Albedos before the first and after the second maxima were dominated by the microrelief roughness of the sphagnum–sedge hummocks.

scholarly journals Accuracy Analysis of International Reference Ionosphere 2016 and NeQuick2 in the Antarctic

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1551
Author(s):  
Zihuai Guo ◽  
Yibin Yao ◽  
Jian Kong ◽  
Gang Chen ◽  
Chen Zhou ◽  
...  
Keyword(s):  
Solar Radiation ◽  
International Reference Ionosphere ◽  
Electron Content ◽  
Observation Data ◽  
Dual Frequency ◽  
Total Electron ◽  
International Reference ◽  
Antarctic Continent ◽  
The Antarctic ◽  
Frequency Observation

Global navigation satellite system (GNSS) can provide dual-frequency observation data, which can be used to effectively calculate total electron content (TEC). Numerical studies have utilized GNSS-derived TEC to evaluate the accuracy of ionospheric empirical models, such as the International Reference Ionosphere model (IRI) and the NeQuick model. However, most studies have evaluated vertical TEC rather than slant TEC (STEC), which resulted in the introduction of projection error. Furthermore, since there are few GNSS observation stations available in the Antarctic region and most are concentrated in the Antarctic continent edge, it is difficult to evaluate modeling accuracy within the entire Antarctic range. Considering these problems, in this study, GNSS STEC was calculated using dual-frequency observation data from stations that almost covered the Antarctic continent. By comparison with GNSS STEC, the accuracy of IRI-2016 and NeQuick2 at different latitudes and different solar radiation was evaluated during 2016–2017. The numerical results showed the following. (1) Both IRI-2016 and NeQuick2 underestimated the STEC. Since IRI-2016 utilizes new models to represent the F2-peak height (hmF2) directly, the IRI-2016 STEC is closer to GNSS STEC than NeQuick2. This conclusion was also confirmed by the Constellation Observing System for Meteorology Ionosphere and Climate (COSMIC) occultation data. (2) The differences in STEC of the two models are both normally distributed, and the NeQuick2 STEC is systematically biased as solar radiation increases. (3) The root mean square error (RMSE) of the IRI-2016 STEC is smaller than that of the NeQuick2 model, and the RMSE of the two modeling STEC increases with solar radiation intensity. Since IRI-2016 relies on new hmF2 models, it is more stable than NeQuick2.

scholarly journals Influence of Seasonal Environmental Variables on the Distribution of Presumptive Fecal Coliforms around an Antarctic Research Station

2003 ◽  
Vol 69 (8) ◽  
pp. 4884-4891 ◽  
Author(s):  
Kevin A. Hughes
Keyword(s):  
Environmental Factors ◽  
Solar Radiation ◽  
Sea Ice ◽  
Fecal Coliform ◽  
Algal Blooms ◽  
Austral Summer ◽  
Fecal Coliforms ◽  
Late Winter ◽  
Research Station ◽  
The Antarctic

ABSTRACT Factors affecting fecal microorganism survival and distribution in the Antarctic marine environment include solar radiation, water salinity, temperature, sea ice conditions, and fecal input by humans and local wildlife populations. This study assessed the influence of these factors on the distribution of presumptive fecal coliforms around Rothera Point, Adelaide Island, Antarctic Peninsula during the austral summer and winter of February 1999 to September 1999. Each factor had a different degree of influence depending on the time of year. In summer (February), although the station population was high, presumptive fecal coliform concentrations were low, probably due to the biologically damaging effects of solar radiation. However, summer algal blooms reduced penetration of solar radiation into the water column. By early winter (April), fecal coliform concentrations were high, due to increased fecal input by migrant wildlife, while solar radiation doses were low. By late winter (September), fecal coliform concentrations were high near the station sewage outfall, as sea ice formation limited solar radiation penetration into the sea and prevented wind-driven water circulation near the outfall. During this study, environmental factors masked the effect of station population numbers on sewage plume size. If sewage production increases throughout the Antarctic, environmental factors may become less significant and effective sewage waste management will become increasingly important. These findings highlight the need for year-round monitoring of fecal coliform distribution in Antarctic waters near research stations to produce realistic evaluations of sewage pollution persistence and dispersal.

Corrigendum - Growth and productivity of irrigated Sorghum bicolor (L. Moench) in Northern Australia. II. Low solar altitude as a possible constraint to productivity in the tropical dry season

1984 ◽  
Vol 35 (2) ◽  
pp. 229
Author(s):  
MA Foale ◽  
GL Wilson ◽  
DB Coates ◽  
KP Haydock
Keyword(s):  
Solar Radiation ◽  
Canopy Structure ◽  
Dry Season ◽  
High Density ◽  
Light Penetration ◽  
Northern Australia ◽  
Growth Study ◽  
Altitude Effect ◽  
Solar Altitude ◽  
Sorghum Bicolor L

A growth study was carried out during the dry season on irrigated grain sorghum cultivar NK 300F at latitude 16�S. in northern Australia. The apparent efficiency of the canopy in the photosynthetic conversion of solar radiation increased progressively in high density stands between June and September, while low density stands showed no change. An hypothesis is advanced that the rise in canopy efficiency was due to increasing solar altitude combining with a suitable canopy structure at high density to give increased light penetration into the canopy. A parameter named weighted mean solar altitude (WMSA) is used in conjunction with noon solar altitude (NSA) to assist in the interpretation of published models of light penetration. This solar altitude effect, if verified by further work, would lower the expectations, based on mean daily solar radiation, for dry season yield of irrigated sorghum and possibly other cereals in the semi-arid tropics.

scholarly journals Concerning the Effect of Anisotropic Scattering and Finite Depth on the Distribution of Solar Radiation in Snow

1975 ◽  
Vol 14 (70) ◽  
pp. 107-124 ◽  
Author(s):  
Bruce R. Barkstrom ◽  
Charles W. Querfeld
Keyword(s):  
Solar Radiation ◽  
Optical Depth ◽  
Scattered Radiation ◽  
Reasonable Agreement ◽  
Finite Depth ◽  
Anisotropic Scattering ◽  
Isotropic Scattering ◽  
Forward Peak ◽  
Angular Reflectance ◽  
Reflectance Data

It is shown that anisotropic scattering with a strong forward peak can give reasonable agreement with angular reflectance data for snow. As a result of the forward peak, solar radiation penetrates deeper into the medium, when measured in terms of photon mean free paths, than it does for isotropic scattering. The radiation transmitted directly through finite slabs can be seen to an optical depth of seven, and decreases much more rapidly with optical depth than does the diffusely transmitted (scattered) radiation.

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