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The lifetime of electric energy in the atmosphere is introduced and investigated as is the total electric energy of the atmosphere related to the total mean rate of electric energy dissipation. This lifetime, as determined from general estimations and convenient analytical expressions, turns out to be very small – from about 10 to about 100 s, depending on the assumptions on the control parameters of principal sources in the global electric circuit. In particular the energy lifetime is less than the relaxation time of the “global condenser” and field relaxation time near the ground surface. It is explained by the high dissipative rate of the electric energy in the atmosphere, taking into account that the regions mainly contributing to the total energy and its dissipative rate are connected to the altitudes of active parts of electrified (thunderstorm) clouds in the atmosphere with exponentially increasing conductivity.  相似文献   
2.
Estimates of lifetimes against pitch angle diffusion   总被引:1,自引:0,他引:1  
We consider timescales on which particle distributions respond to pitch angle diffusion. On the longest timescale, the distribution decays at a single rate independent of equatorial pitch angle α0, even though the diffusion coefficient, and the distribution itself, may vary greatly with α0. We derive a simple integral expression to approximate this decay rate and show that it gives good agreement with the full expression. The roles of both the minimum and loss cone values of the diffusion coefficient are demonstrated and clarified.  相似文献   
3.
Real-time N2O measurements have been madein situ at the South Pole, Antarctica, north and south of the equator from on board the Alpha Helix and over the Pacific Ocean on several aircraft flights from the U.S. to New Zealand, Australia and 90°S. In addition, an automated EC-GC has been operated for the past year intermittently monitoring N2O in surface air at a rural site in the wheatlands of eastern Washington state. The data obtained are consistent and in agreement with the data obtained from the analyses of a large number of samples collected both from ground stations and a variety of aircraft flights made in the southern and northern hemisphere. The observed global data show no interhemispheric differences. The present concentration of N2O in the troposphere is measured to be 330±3 ppbv. Its vertical distribution in the troposphere is very uniform. A small decrease (2–3 percent) across the tropopause is characteristically observed in the high altitude Learjet flights.  相似文献   
4.
Arsenic in drinking water has been shown to increase the risk of urothelial carcinoma and lung cancer. However, the lifetime risk of developing urothelial carcinoma and lung cancer caused by exposure to arsenic in drinking water has not been reported. This study aimed to assess the lifetime risk of urothelial carcinoma and lung cancer caused by arsenic exposure from drinking water and cigarette smoking habit for residents living in the arseniasis-endemic area in Northeastern Taiwan. We recruited 8086 residents in 1991–1994 and monitored them for their newly developed types of cancers, identified by computerized linkage with the national cancer registry profile. There were 37 newly diagnosed urothelial carcinoma cases and 223 new lung cancer cases during the follow-up period (until 2007). The lifetime (35–85 years old) cumulative risk of developing urothelial carcinoma from an arsenic concentration in the drinking water of <10, 10–99, and 100+ μg/L was 0.29%, 1.07% and 3.43%, respectively. The corresponding probabilities were 7.42%, 8.99% and 17.09% for the lifetime risk of developing lung cancer. Cigarette smoking was associated with an increased risk of urothelial carcinoma and lung cancer, showing the hazard ratio (95% confidence interval) of 2.48 (1.27–4.82) and 3.44 (2.00–5.90) after adjusting for the arsenic concentration in drinking water. After adjusting for cigarette smoking, the hazard ratio (95% confidence interval) of developing urothelial carcinoma caused by the arsenic concentration in drinking water of <10, 10–99 and 100+ μg/L was 1.0 (the reference group), 2.18 (0.59–8.01), and 8.71 (2.49–30.48), respectively. The corresponding figures were 1.0 (the reference group), 1.14 (0.80–1.61), 1.84 (1.28–2.65) for lung cancer. Synergistic effects on the development of urothelial carcinoma and lung cancer existed between the arsenic exposure level and cigarette smoking. It is suggested that people who have had a high exposure to arsenic in drinking water should stop smoking cigarettes to lower their lifetime risk of urothelial carcinoma and lung cancer.  相似文献   
5.
H2S is a most important biogenic sulfur compound with regard to the atmospheric sulfur cycle. Our present knowledge of the spatial and temporal distribution of this trace gas is rather incomplete owing to unreliable analytical methods. Therefore, a new method for the analysis of H2S in the g-range was applied. This paper deals with the results of ground- and aircraft measurements of H2S in unpolluted air over swamps and tidal flats. Based on the measured vertical distributions a removal coefficient of 2.3×10–5 sec–1 and an average lifetime of 12 hours were calculated. Some conclusions of the contribution of H2S to the atmospheric sulfur budget are added.  相似文献   
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