For example, over Antarctica, cold temperatures cause ice particles Polar Stratospheric Clouds to form in the stratosphere. The nuclei for these particles are thought to be sulfuric acid aerosol, possibly of volcanic origin. The ice particles provide the surfaces that allow complex chemical reactions to take place in a manner than can deplete stratospheric ozone.
The eruption of Mt. Over millions of years, the biosphere has evolved to deal with temporary increases in UV from reductions in stratospheric ozone by natural causes such as volcanic eruptions, but has not had the time required to adjust to long-term ozone reductions attributed to human activities of the last 30 years.
Photograph courtesy USGS. Water Depth UV-B exposure decreases rapidly at increasing depths in the water column. In other words, water and the impurities in it strongly absorb and scatter incoming UV-B radiation. Some substances that are dissolved in water, such as organic carbon from nearby land, will also absorb UV-B radiation and enhance protection of microorganisms, plants, and animals from UV-B. Different masses of water at different locations contain different amounts of such dissolved substances and other particles, making evaluation of UV damage very difficult.
Ultraviolet B UV-B radiation reaches different depths in ocean water depending on water chemistry, the density of phytoplankton, and the presence of sediment and other particulates. The map above indicates the average depth UV-B penetrates into ocean water. The rest was absorbed or scattered back towards the ocean surface. Image courtesy Vasilkov et al. Eustachian Tube Balloon Dilation. Head and Neck Cancer. Pediatric Airway. Pediatric ENT. Sinuva treatment for sinusitis.
Thyroid Surgery. Tonsils and Adenoids. Astigmatism, Myopia and Presbyopia. Cataracts and Cataract Surgery. Common Eye Problems. Corneal Cross-Linking. Diabetic Eye Care. Dry Eye. Femto Laser Assisted Cataract Surgery. Implantable Contact Lenses. Pediatric Eye Care. Pink Eye and Other Eye Infections. Refractive Eye Surgery. Refractive Lens Exchange. Stye and Chalazion. Chemical Peel. Cleft lips and cleft palates. August 21, Four of the telescopes on the Solar Dynamics Observatory observe extreme ultraviolet light activity on the sun that is invisible to the naked eye.
Spacecraft record solar activity as a binary code, 1s and 0s, which computer programs can translate into black and white. Scientists colorize the images for realism, and then zoom in on areas of interest. Provided by NASA. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission.
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