Atmospheric effects on radiometry from zenith of a plane with dark vertical protrusions

Effects of an optically thin plane-parallel scattering atmosphere on radiometric imaging from the zenith of a specific surface-type are analyzed. The surface model was previously developed to describe arid steppe, where the sparse vegetation forms dark vertical protrusions from the bright soil-plane. The analysis is in terms of the surface reflectivity to the zenith r sub p for the direct beam, which is formulated as r sub p = r sub i exp (-s tan theta sub 0), where v sub i is the Lambert law reflectivity of the soil, the protrusions parameters s is the projection on a vertical plane of protrusions per unit area and theta sub 0 is the zenith angle. The surface reflectivity r sub p is approximately equal to that for the global irradiance (which is directly measured in the field) only for a narrow range of the solar zenith angles. The effects of the atmosphere when imaging large uniform areas of this type are comparable to those in imaging a Lambert surface with a reflectivity r sub p. Thus, the effects can be approximated by those in the case of a dark Lambert surface (analyzed previously), inasmuch as r sub p is smaller than the soil reflectivity r sub i for any off-zenith illumination. The surface becomes effectively darker with increasing solar zenith angle. Adjacency effects of a reflection from one area and scattering in the instantaneous field of view (object pixel) are analyzed as cross radiance and cross irradiance

Single scattering solution for radiative transfer through Rayleigh and aerosol atmosphere

A solution is presented to the radiative transfer of the solar irradiation through a turbid atmosphere, based on the single-scattering approximation, i.e., an assumption that a photon that underwent scattering either leaves the top of the atmosphere or strikes the surface. The solution depends on a special idealization of the scattering phase function of the aerosols. The equations developed are subsequently applied to analyze quantitatively the enhancement of the surface irradiation and the enhancement of the scattered radiant emittance as seen from above the atmosphere, caused by the surface reflectance and atmospheric back scattering. An order of magnitude error analysis is presented

Enhancement of surface-atmosphere fluxes by desert-fringe vegetation through reduction of surface albedo and of soil heat flux

Under the arid conditions prevailing at the end of the dry season in the western Negev/northern Sinai region, vegetation causes a sharp increase relative to bare soil in the daytime sensible heat flux from the surface to the atmosphere. Two mechanisms are involved: the increase in the surface absorptivity and a decrease in the surface heat flux. By increasing the sensible heat flux to the atmosphere through the albedo and the soil heat flux reductions, the desert-fringe vegetation increases the daytime convection and the growth of the planetary boundary layer. Removal of vegetation by overgrazing, by reducing the sensible heat flux, tends to reduce daytime convective precipitation, producing higher probabilities of drought conditions. This assessment of overgrazing is based on observations in the Sinai/Negev, where the soil albedo is high and where overgrazing produces an essential bare soil. Even if the assessment for the Sinai/Negev does not quantitatively apply throughout Africa, the current practice in many African countries of maintaining a large population of grazing animals, can contribute through the mesoscale mechanisms described to reduce daytime convective precipitation, perpetuating higher probabilities of drought. Time-of-day analysis of precipitation in Africa appears worthwhile, to better assess the role of the surface conditions in contributing to drought

Earth-atmosphere system and surface reflectivities in arid regions from LANDSAT multispectral scanner measurements

Programs for computing atmospheric transmission and scattering solar radiation were used to compute the ratios of the Earth-atmosphere system (space) directional reflectivities in the vertical direction to the surface reflectivity, for the four bands of the LANDSAT multispectral scanner (MSS). These ratios are presented as graphs for two water vapor levels, as a function of the surface reflectivity, for various sun elevation angles. Space directional reflectivities in the vertical direction are reported for selected arid regions in Asia, Africa and Central America from the spectral radiance levels measured by the LANDSAT MSS. From these space reflectivities, surface vertical reflectivities were computed applying the pertinent graphs. These surface reflectivities were used to estimate the surface albedo for the entire solar spectrum. The estimated albedos are in the range 0.34-0.52, higher than the values reported by most previous researchers from space measurements, but are consistent with laboratory measurements

Multidisciplinary uses in Israel

There are no author-identified significant results in this report

Climatic change by cloudiness linked to the spatial variability of sea surface temperatures

An active role in modifying the earth's climate is suggested for low cloudiness over the circumarctic oceans. Such cloudiness, linked to the spatial differences in ocean surface temperatures, was studied. The temporal variations from year to year of ocean temperature patterns can be pronounced and therefore, the low cloudiness over this region should also show strong temporal variations, affecting the albedo of the earth and therefore the climate. Photographs are included

Possible rainfall reduction through reduced surface temperatures due to overgrazing

Surface temperature reduction in terrain denuded of vegetation (as by overgrazing) is postulated to decrease air convection, reducing cloudiness and rainfall probability during weak meteorological disturbances. By reducing land-sea daytime temperature differences, the surface temperature reduction decreases daytime circulation of thermally driven local winds. The described desertification mechanism, even when limited to arid regions, high albedo soils, and weak meteorological disturbances, can be an effective rainfall reducing process in many areas including most of the Mediterranean lands

The US influence in shaping Iraq's sectarian media

After the Anglo-American invasion, the US neo-conservative administration established the Iraqi Governing Council in July 2003, which included 25 members selected for their ethnic and religious origins; it was the most obvious sign of the US political separatist strategy. As a result of the new political reality, the Iraqi media was divided into ethno-sectarian lines, resulting from previous policies followed by the US administration. This article argues that the US media policy prior and after the US invasion of Iraq played a part in enhancing and encouraging the sectarian divisions in the Iraqi society. This was mainly done by sending biased media messages through the state-run Iraqi Media Network (IMN) and other US-aligned channels and allowing militant voices from different Iraqi sides to wage wars of words without interfering. In fact, the only time US officials interfered is when they were criticized by Iraqi media outlets. This study cites different US government reports, accounts from media practitioners who worked for IMN and other journalists that monitored the Iraqi media

Surrounded by sound: noise, rights and environments

Noise was probably the first environmental pollutant (apart from human waste) in the Ancient world. Yet today, by comparison with other environmental matters, noise and protection from its effects are often overlooked, except in specialist fields such as architecture or planning. One major reason for this may be that noise does not possess the same ability to spread that is characteristic of other forms of pollution. Noise is also an unusual form of environmental pollution in having a physical impact – it is ‘heard’ and can be ‘felt’ – but is predominantly interpreted subjectively. The impact and consequences of anthropogenic noise for humans and biodiversity in general, are currently under-investigated in criminology and are under-addressed in both public and private international environmental law. Here we question why noise has not (so far) been explored within green criminology and only tentatively explored within cultural criminology. The objectives are to provide an overview of noise as a topic, connecting media, culture, anti- and pro-social behaviour, and to unearth interconnections between the matter of noise and its implications for the environment

Precision Measurement of the Spin-dependent Asymmetry in the Threshold Region of 3He⃗(e⃗,e′)^3\vec{\mathrm{He}}(\vec{e},e')

We present the first precision measurement of the spin-dependent asymmetry in the threshold region of $^3\vec{\rm He}(\vec{e},e')$ at $Q^2$-values of 0.1 and 0.2 (GeV/c)$^2$. The agreement between the data and non-relativistic Faddeev calculations which include both final-state interactions (FSI) and meson-exchange currents (MEC) effects is very good at $Q^2$ = 0.1 (GeV/c)$^2$, while a small discrepancy at $Q^2$ = 0.2 (GeV/c)$^2$ is observed.Comment: 5 pages, 2 figures, 2 tables. To appear in Phys. Rev. Let