Influence of the total atmospheric optical depth and cloud cover on solar irradiance components

Broadband solar irradiance data obtained in the spectral range 400–940 nm at Kwangju, South Korea from 1999–2000 have been analyzed to investigate the effects of cloud cover and atmospheric optical depth on solar radiation components. Results from measurements indicate that the percentage of direct and diffuse horizontal components of solar irradiance depend largely on total optical depth (TOD) and cloud cover. During summer and spring, the percentages of diffuse solar irradiance relative to the global irradiance were 5.0% and 4.9% as compared to 2.2% and 3.0% during winter and autumn. The diffuse solar irradiance is higher than the direct in spring and summer by 24.2%, and 40.6%, respectively, which may largely be attributed to the attenuation (scattering) of radiation by heavy dust pollution and large cloud amount. In cloud-free conditions with cloud cover ≤2/10, the fraction of the direct and diffuse components were 66.0% and 34.0%, respectively, with a mean daily global irradiance value of 7.92±2.91 MJ m⁻² day⁻¹. However, under cloudy conditions (with cloud cover ≥8/10), the diffuse and direct fractions were 97.9% and 2.2% of the global component, respectively. The annual mean TOD under cloudless conditions (cloud cover≤2/10) yields 0.74±0.33 and increased to as much as 3.15±0.67 under cloudy conditions with cloud amount ≥8/10. An empirical formula is derived for estimating the diffuse and direct components of horizontal solar irradiance by considering the total atmospheric optical depth (TOD). Results from statistical models are shown for the estimation of solar irradiance components as a function of TOD with sufficient accuracy as indicated by low standard error for each solar zenith angle (SZA).     

Toxic (mercury,berillium) and biogenic (selenium,fluorine) elements in aquatic ecosystems of Baikal Natural Territory

Up-to-date analytical methods are used to collect data on the concentrations of toxic (mercury, beryllium) and biogenic (selenium, fluorine) elements in various aquatic landscape-geochemical systems of Baikal Natural Territory, including the central, buffer zone, and the zone of atmospheric influence. The concentrations of selenium and fluorine were found to far below (with rare exceptions) their hygienic standards for drinking water. By this characteristic, the Baikal Natural Territory is classified as a deficient biogeochemical province. The low concentrations (up to nanograms) of highly toxic elements—mercury and beryllium—in surface and subsurface waters of aquatic landscapes show that the considered ecological zones are quite favorable for human life. Studying microelements in landscape-geochemical zones opens the way for environmentally safe nature management in the territory and enables one to forecast variations in the quality of water resources under growing anthropogenic load.     

Methane Production in a West Siberian Eutrophic Fen Is Much Higher than Carbon Dioxide Production: Incubation of Peat Samples,Stoichiometry, Stable Isotope Dynamics,Modeling

Water Resources - Homoacetogenic bacteria can play an important role in anaerobic degradation of organic matter in peatlands at low temperatures. However, little is known about the conditions when...     

THE DEEPER GROUND WATER IN LIBYA

Abstract

A synthetic diurnal energy budget averaged for each month of the year shows that Lake Ontario loses very little heat at night during April, May, and June. The nightly losses during July, August, and September are conjectured to contribute significantly to the deepening of the thermocline through vertical convection.     

The ADSS-3 broadband stand-alone digital seismic station

The SSD-3 three-channel seismic recorder and the ADSS-3 three-component broadband standalone digital seismic station based on the SSD-3 together with SM-3E seismic sensors were developed. The main advantage of this equipment in comparison with foreign and domestic analogs is simplicity and convenience while maintaining high technical characteristics. The structure and operation of the seismic sensor and seismic recorder are considered, and their main technical characteristics are given. Laboratory, bench, and comparative tests of the seismic recorder and station demonstrated their working capacity and compliance with the development goal. Based on the test results, the ADSS-3 seismic station was commissioned as a three-component broadband observation point of the Mikhnevo small-aperture seismic array. The data obtained using the ADSS-3 made is possible to study the structure of the crust and upper mantle of this region using the receiver function method.     

STATISTICAL EVALUATION OF MT AND AMT METHODS APPLIED TO A BASALT-COVERED AREA IN SOUTHEASTERN ANATOLIA,TURKEY*

The efficacy of the magnetotelluric and audiomagnetotelluric (MT/AMT) methods for detailing the structure of a hypothetical geological section is investigated by using the singular value decomposition (SVD) technique. The section is representative of southeastern Turkey, which is mostly covered by basalt and is a prime area for oil exploration. One of the geological units, the Germav shale at a depth of 600 m, is a problem layer for electromagnetic surveys because of its very low resistivity (on average 3 Ωm) and highly variable thickness across the area (200–900 m). In the MT frequency range (0.0004–40 Hz) its total conductance—or, since its resistivity is known from resistivity log information, its thickness—is the best resolved model parameter. The total depth to the Germav shale and the resistivity of the Cambrian/Precambrian basement are the marginally resolved parameters. In the AMT frequency range (4–10000 Hz) the resistivity of the surface basalt layer strongly affects the resolution of the other, less important, model parameters which are the total depth to the Germav shale and the total conductance of the Germav shale. The errors in the measurements determine the number of model parameters resolvable, and are also important for interpretation of the geological model parameters to within a desired accuracy. It is shown that statistical evaluation of the MT and/or AMT interpretations by using an SVD factorization of the sensitivity matrix can be helpful to define the importance of some particular stage of the interpretation, and also provides a priori knowledge to plan a proposed survey. Arrangements of MT and AMT observations, together with some Schlumberger resistivity soundings, on a large grid will certainly provide three-dimensional detailed information of the deep geoelectric structure of the area.     

About the Role of Quinones in the Action of Some Polyphenols on the Streaming of Protoplasm in Nitella sp. Cells

The concentration of phenols and quinones which stopped the protoplasmic movement in the Nitella cells after 15 min was determined. The quinones (β-naphthoquinone, α-naphthoquinone, p-benzoquinone, o-toluquinone, o-bromanil) stopped the protoplasmic movement in the concentration of (1 3) 10^?4 M, phenols (m-cresol, p-cresol, hydroquinone, guaiacol, phenol, gallic acid, pyrogallic acid, resorcinol) in the concentration of (0.2 5) 10^?2 M, except catechol – 2 10^?3 M. Very high toxicity of catechol and in the prolonged experiments (3 hours) also of hydroquinone is connected with the action of quinonoid productions of its oxidation. This suggestion is confirmed by the experiments:

• – by adding the phenol solutions to Nitella shoots (catechol, hydroquinone, resorcinol) we observed the greatest increase of oxygen absorption in case of catechol (86%), less in case of hydroquinone (38%), and for resorcinol oxygen absorption practically remained on the control level;
• – the action of catechol, hydroquinone and p-benzoquinone did not take place in the presence of glutathione and cysteine (but not cystine and oxidated glutathione);
• – diethyldithiocarbamate as an inhibitor of o-diphenoloxidase reduced the ability of catechol solutions to stop the protoplasmic movement;
• – the low concentrations of benzoquinones were able to stop the protoplasmic movement;
• – for stopping the protoplasmic movement under the prolonged time of incubation from 15 min to 3 hours there was necessary a lower concentration of solutions of hydroquinone and catechol in comparison with resorcinol.

     

Method of monitoring atomic oxygen and molecular nitrogen composition in the upper atmosphere on XUV images of the Sun

A method for determining the basic atmosphere O/N₂ based on the solar observations is described. It is shown that, on XUV images of the Sun received by transillumination of the atmosphere, it is possible to observe its state controlling the O/N₂ ratio. The method allows local inhomogeneities of the upper atmosphere to be studied. Its abilities were demonstrated according to the SPIRIT complex on board the Coronas-F satellite.     

Storm track response to ocean fronts in a global high-resolution climate model

Synoptic atmospheric eddies are affected by lower tropospheric air-temperature gradients and by turbulent heat fluxes from the surface. In this study we examine how ocean fronts affect these quantities and hence the storm tracks. We focus on two midlatitude regions where ocean fronts lie close to the storm tracks: the north-west Atlantic and the Southern Ocean. An atmospheric climate model of reasonably high resolution (~50 km) is applied in a climate-length (60 year) simulation in order to obtain stable statistics. Simulations with frontal structure in the sea surface temperature (SST) in one of the regions are compared against simulations with globally smoothed SST. We show that in both regions the ocean fronts have a strong influence on the transient eddy heat and moisture fluxes, not just in the boundary layer, but also in the free troposphere. Local differences in these quantities between the simulations reach 20–40 % of the maximum values in the simulation with smoothed SST. Averaged over the entire region of the storm track over the ocean the corresponding differences are 10–20 %. The effect on the transient eddy meridional wind variance is strong in the boundary layer but relatively weak above that. The potential mechanisms by which the ocean fronts influence the storm tracks are discussed, and our results are compared against previous studies with regional models, Aquaplanet models, and coarse resolution coupled models.