نتایج جستجو برای: terrestrial atmosphere
تعداد نتایج: 87850 فیلتر نتایج به سال:
Nitrogen (N) cycling in terrestrial ecosystems is a global environmental concern. The N cycle is a complex interplay where biotic and abiotic processes interact to transform and transfer N in an ecosystem. In general, one can simplify by classifying terrestrial N cycles all over the world in two groups: ‘tight’ N cycles and ‘open’ N cycles. The ‘tight’ N cycle is characterized by its high effic...
Ozone depletion results in greater amounts of UV-B radiation that had an impact on terrestrial and aquatic biogeochemical systems. Biogeochemical cycles were the complex interactions of physical, chemical, geological and biological processes that control the transport and transformation of substances in the natural environment and therefore the conditions that humans experience in Earth's syste...
Terrestrial gamma-ray flashes (TGFs) are very short bursts of high-energy photons and electrons originating in Earth's atmosphere. We present here a localization study of TGFs carried out at gamma-ray energies above 20 MeV based on an innovative event selection method. We use the AGILE satellite Silicon Tracker data that for the first time have been correlated with TGFs detected by the AGILE Mi...
Estuarine and shallow coastal systems (ESCS) are recognized as not only significant organic carbon reservoirs but also emitters of CO2 to the atmosphere through air-sea CO2 gas exchange, thus posing a dilemma on ESCS's role in climate change mitigation measures. However, some studies have shown that coastal waters take up atmospheric CO2 (Catm), although the magnitude and determinants remain un...
We present simulations of atmospheres of Earth-like aquaplanets that are tidally locked to their star, that is, planets whose orbital period is equal to the rotation period about their spin axis, so that one side always faces the star and the other side is always dark. Such simulations are of interest in the study of tidally locked terrestrial exoplanets and as illustrations of how planetary ro...
An integrated modelling approach is proposed for the assessment of the nutrient loading of a coastal marine ecosystem from terrestrial sources. The evaluation of the model was based on a data set collected on a monthly basis from a Greek gulf surrounded by an intensively cultivated watershed. It consisted of three interacting components, that is the terrestrial, the hydrodynamic and the biologi...
From a comparison of C14/C1s and Cla/C1* ratios in wood and in marine material and from a slight decrease of the C14 concentration in terrestrial plants over the past 50 years it can be concluded that the average lifetime of a CO, molecule in the atmosphere before it is dissolved into the sea is of the order of 10 years. This means that most of the CO, released by artificial fuel combustion sin...
US National Report to International Union of Geodosy and Geophysics 1987–1990, Review of Geophysics, Supplement, pp. 1143–1165. Hedin AE and Carignan GR (1985)Morphology of thermospheric composition variations in the quiet polar mesosphere from Dynamics Explorer measurements. Journal of Geophysical Research 90: 5269–5277. Killeen TL (1987) Energetics of the Earth’s thermosphere. Reviews of Geop...
The bulk of the sun's radiation is in the visible and infrared. Solar radiation at these wavelengths controls the weather in the lowest levels of the earth's atmosphere. The rate at which this energy is emitted (the so-called solar constant) varies by a few tenths of 1 percent over a time scale of days. Longer period variations may exist, but have yet to be detected. Far more variable are the a...
Only 17 per cent of French households received digital television in 2002. Hence, for public authorities, digital terrestrial television (DTTV) is mainly a means to stimulate the development of digital television. However, cable and satellite operators (TF1, M6 and Canal Plus), which have been designated as leaders of the DTTV process, are reluctant, as they view DTTV as a competitor to their e...
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