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W Ambach

Publications and source records attributed to W Ambach.

At least 37 records · Page 2Linked to original sources
PubMed1990

Indication of increasing solar ultraviolet-B radiation flux in alpine regions.

Measurements at the Jungfraujoch High Mountain Station (Swiss Alps, 47 degrees N, 3576 meters above sea level) indicate that there has been a slight increase of about 1 percent per year in the flux of solar ultraviolet-B radiation (290 to 330 nanometers) since 1981. A Robertson-Berger detector was used to measure solar erythemal radiation. The increase can be related to a long-term ozone depletion.

Altitude↗
PubMed1989

Chernobyl fallout on Alpine glaciers.

Measurements of the gross beta activity of snow samples from four Alpine glaciers contaminated by radioactive fallout from the Chernobyl nuclear accident and a gamma-spectrum analysis of selected samples are reported. The results are discussed with respect to possible risks to the population from using meltwater from these glaciers as drinking water.

Accidents↗
PubMed1988

Displacement of Chernobyl fallout in snow layers of temperate Alpine glaciers.

Measurements of the gross-beta-activity and a gamma-spectrum analysis of radioactive fallout from Chernobyl distributed in vertical snow profiles on an Alpine glacier were carried out. Samples were collected in summer 1986 and in summer 1987. A displacement of isotopes to depths of approximately 6 m was observed. The mean activity per unit area amounts to 10.4 and 6.6 kBq m-2 for samples from 1986 and 1987, respectively, both values corrected to 1 May 1987. Isotopes with half-lives shorter than 110m Ag (250 days) could no longer be detected in 1987.

Accidents↗
PubMed1988

Physical assessment of heat insulation rescue foils.

For the insulation of hypothermic individuals, aluminium-coated foils are used as rescue blankets and rescue suits, respectively. By measurements on a phantom, the efficiency of these foils was tested. Based on an appropriate physical model results were transferred to the thermal reaction of hypothermic individuals. Following investigations were carried out: rescue foil with different types of clothing, comparison between rescue foil and woolen blanket, "Hibler packing", rescue suit at sudden fall in temperature. Applying these foils and the suit, respectively, a thermal stabilization of the body core is being achieved approximately under realistic conditions. When applying the "Hibler packing", reheating is achieved both with wet and dry clothing.

Clothing↗
PubMed1987

On the threshold radiant exposure for keratitis solaris.

Marked inflammation of the cornea (keratitis solaris) is often observed after exposure to strong solar radiation, especially in high altitudes and snow-covered terrain. Using the action spectrum and the solar spectrum, the radiant exposure causing keratitis solaris was calculated for a horizontal surface. The parameters selected were altitude, season, ozone content and albedo. The radiant exposure of the eye increases approximately 16-fold, comparing terrain without snow-cover and terrain with snow-cover. Radiant exposures in clinically observed cases of keratitis solaris were calculated to range from 1200 to 5600 Jm-2. A discussion on these figures with regard to threshold doses shows a significant difference between long-term exposure to solar radiation and short-term exposure to artificial sources.

Humans↗
PubMed1985

[Calculation of radiation dose in changes in solar UV-B radiation with regard to keratitis photoelectrica].

With the help of the keratitis action spectrum and the solar spectrum for various elevations, the intensity of solar radiation that produces keratitis is calculated depending on altitude for terrain with and without snow cover. There is a 17-fold increase in midday solar intensity from winter to summer. In summer the intensity increases by 16% for every 1000 meters of altitude. For a subject observing snow-covered terrain, the intensity is 16 times greater than when the same terrain is observed without snow cover. For clinically observed cases of photoelectric keratitis caused by solar radiation it is possible to calculate the doses involved. They range between 1200 J/m2 and 5600 J/m2. These values are discussed in terms of a threshold dose, and it is concluded that this threshold dose is much higher than in the case of short-term irradiation such as occurs during welding. The difference between these two threshold doses is presumably explained by a repair mechanism.

Altitude↗
PubMed1985

Contamination of firn layers by radioactive fission products from atmospheric fallout.

Measurements of gross beta activity and 3H concentration of firn samples from different regions can be used to determine environmental contamination by radioactive fallout from nuclear weapons tests in the atmosphere since 1952. The exposure dose to the population due to radioactive fission products in the drinking water supply from glacierized areas is compared to maximum acceptable concentrations derived from ICRP annual limits of intake (ALI). It is shown that even from heavily contaminated layers the risk to the population is acceptable.

Arctic Regions↗
PubMed1983

Measurements of the annual variation of the erythema dose of global radiation.

The share of erythema dose of global radiation (Der/G) shows significant diurnal and annual variations. This is the result of the dependence of the ratio Der/G on optical air mass. Maximum values of Der/G are found at times of low optical air mass, i.e., at noon and in summer, minimum values at sunrise and sunset hours as well as in winter. Another reason for the annual variation of the ratio Der/G is the changing amount of total atmospheric ozone. Therefore values of Der/G in fall are about 50% higher than in spring despite the same solar declination. Comparing measurements of erythema dose at two stations with different altitudes, a difference of 14% per 1,000 m is obtained.

Erythema↗