نتایج جستجو برای: ozone layer depletion
تعداد نتایج: 361253 فیلتر نتایج به سال:
Based on cosmological rates, it is probable that at least once in the last Gy the Earth has been irradiated by a gamma-ray burst in our Galaxy from within 2 kpc. Using a two-dimensional atmospheric model we have computed the effects upon the Earth's atmosphere of one such burst. A ten second burst delivering 100 kJ/rn2 to the Earth results in globally averaged ozone depletion of 35%, with deple...
Declining levels of stratospheric ozone resulting from anthropogenic source gases is internationally recognized as one of the Earth’s most important environmental issues. In the last twenty years, global ozone trends show that concentrations are decreasing by 2-5% per decade in the middle latitudes. The societal concern is that with decreasing concentrations of ozone, the amount of the Sun’s ul...
The annual cycle of formaldehyde (HCHO) has been investigated at a remote surface-site in Antarctica. HCHO mixing-ratios during the period of stratospheric ozone depletion are significantly higher than during times of similar sunshine duration in austral autumn. This might be due to enhanced UV-B radiation.
The complexity of the linkages between ozone depletion, UV-B radiation and climate change has become more apparent.
Heterogeneous reactions in the Antarctic stratosphere are the cause of chlorine activation and ozone depletion, but the relative roles of different types of polar stratospheric clouds (PSCs) in chlorine activation is an open question. We use multi-year simulations of the chemistryclimate model ECHAM5/MESSy for Atmospheric Chemistry (EMAC) to investigate the impact that the various types of PSCs...
Abstract. There is evidence that the ozone layer has begun to recover owing ban on production of halogenated ozone-depleting substances (hODS) accomplished by Montreal Protocol and its amendments adjustments (MPA). However, recent studies, while reporting an increase in tropospheric from anthropogenic NOx CH4 confirming recovery upper stratosphere effects hODS, also indicate a continuing declin...
Ozone depletion led to a positive trend in the summertime Southern Annular Mode (SAM) during last decades of 20th century. During present century, global warming (GW) is expected contribute SAM while ozone recovery act opposite direction. Here, Hemisphere (SH) circulation and regional precipitation change are studied with methodology that separates effects from GW depletion/recovery. Our result...
Human activities are placing enormous pressures on the biosphere. The introduction of new chemicals and the increasing ambient levels of existing chemicals have resulted in atmospheric degradation. This paper reviews some of the adverse effects of stratospheric ozone depletion and global warming. Because the atmospheric effects of ozone depletion are fairly well characterized, quantitative risk...
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