The IMF sector structure effects in total ozone in central Europe

Summary The influence of the IMF sector structure on the total ozone content is studied in the European middle latitudes (5 stations,46°–52°N, 1°W–20°E) for the winters of the period 1963–1982. The average effect of the IMF sector boundary crossing (SBC) is very weak. The correction for the seasonal trend is quite crucial. Only detrended results are considered to be reliable. A statistically significant and relatively large effect is found to exist in the total ozone only for geoactive proton sector boundaries, while there is no demonstrable effect for non-proton (common) sector boundaries. The effect of proton boundaries consists in a decrease of the total ozone from higher values before the IMF SBC to lower values after the IMF SBC and it differs from the common types of IMF SBC effects. Our results seem to explain the contradiction between results obtained by other authors.

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¶rt;m uu m mm nam aum n () a n ¶rt;au a nu ¶rt;u uma (5 mau, 46° – 52° .., 1° .¶rt;. – 20° .¶rt;.) ¶rt; u nu¶rt;a 1963–1982. ¶rt;u m nu mau () a. naa a m¶rt; ma. mam mau m¶rt;a umam ¶rt;mu. mamumuu au u a m a¶rt; n ¶rt;auu a m ¶rt;amu nm mau. a mau ua ma m. m nm mau mum na¶rt;uu n ¶rt;au a u au ¶rt; ¶rt; uu au n . a am, m au mam m nmuu ¶rt; mamau ¶rt;u am.

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Presented at the XIX General Assembly of IUGG, Vancouver 1987.     

Stresses and displacements in the lithosphere due to terrain topography

Summary The complete two-dimensional theory of stresses and displacements in the loaded elastic floating lithosphere is presented. Analytical expressions are derived describing these quantittes as functions of the physical and geometrical parameters of the model. It is shown that horizontal stresses _xx may considerably exceed the surface load and that values of _xx200 MPa can be generated under certain conditions. Numerical calculations are carried out for geophysically acceptable input parameters.

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am na ¶rt;a mu anu u u a n naa um. ¶rt; aaumuu au, nuau mu uu a uu m uuu umuu naam ¶rt;u. aa, muma anu m aum num anu nm au u m¶rt; a m m n¶rt;a 200 a. n u am ¶rt;uuu ¶rt;nmu ¶rt; naam.

     

The12C/13C isotope ratio in comets,stars and interstellar matter

The¹²C/¹³C isotope ratio in the interstellar medium and in stellar atmospheres is discussed and compared to the value found in the solar system and especially in comets. The cometary value (100) tends to be slightly above the terrestrial value and is definitively higher than that for interstellar molecular clouds (about 30 to 50).This result implies that comets are not of interstellar origin; that the original isotopic abundances of the primitive solar nebula has been preserved in the cometary material; and that due to an enrichment of the interstellar medium in¹³C, the¹²C/¹³C isotope ratio has decreased by a factor of about 2.5 since the formation of the solar system (i.e., during the past 4.5×10⁹ years) — a result which is roughly in agreement with present theories of the chemical evolution of our Galaxy. The relatively high cometary carbon isotope ratio (as compared to the terrestrial value) indicates that some correction should be applied to the semi-empirical models describing the¹³C enrichment in the Galaxy.Paper dedicated to Professor Hannes Alfvén, on the occasion of his 70th birthday, 30 May, 1978.     

A fishery in a changing lake environment: The naked carpGymnocypris przewalskii (Kessler) (Cyprinidae: schizothoracinae) in Qinghai Hu,China

Quinghai Hu is a large, high-altitude, saline lake in north-western China, and supports a fishery based on an endemic species of naked carp (snow trout). The fish take seven years to attain maturity and a marketable weight of 300 g, and have a lifespan of 14–21 years under the present fishery regime. They seasonally migrate from the lake to spawn over the gravel beds of inflowing rivers, but these areas have been reduced by weirs and irrigation diversions and recruitment may have declined. The population may have been affected also by a 1.85-m fall in the lake level over the past 30 years, and by associated changes in salinity. The fishery was opened to large-scale exploitation in 1958. Yields declined sharply (max. 28,523 tonnes, 1960) as the larger, older fish were removed, and then more slowly (min. 2523 tonnes, 1983). Since 1987 the fish factory has been limited to an annual quota of 1200 tonnes, taken by a fleet of four pair trawlers. Another 800 tonnes are taken by licensed fishermen, mainly using gill nets, and perhaps 1000 tonnes are taken illegally. The estimated total catch in 1992 was 3000 tonnes. New trawlers introduced in 1989–90 substantially increased the factory's catch per unit effort, and in 1990 the quota was virtually filled in one month in a zone within 20 km of the factory. Although this could suggest that the stocks will be conserved if the quota is retained, at least half of the catch in 1989–92 consisted of immature individuals. Trawling operations recently were suspended following a further decline in the catch after 1992. While the new trawlers are capable of a major increase in effort, neither the changing environment, the fish stocks or the present markets favour intensified pressure. Gillnets may provide better control over the minimum size limit and may cause less damage than trawling. Other options to improve the viability and profitability of the fishery include improvements in handling, processing and marketing. Failure to develop the fishery may encourage attempts to introduce exotic fish, at some risk to survival of the local species.     

Weather and traffic accidents in the Czech Republic, 1979–2020

Theoretical and Applied Climatology - Police records, kept in the form of yearbooks, enabled analysis of the possible relationships between traffic accidents and the weather in the Czech Republic...