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311.
One strand of research relates the magnitude of severe weather disasters to climatic and human development factors; another highlights dramatic growth in catastrophe losses. However, there have been few attempts to put the two strands together. Here we use an explicit modeling framework to determine the contribution of climate variability relative to human factors in reported catastrophe losses. We then examine how future climate change can be expected to affect losses from natural disasters. Simultaneous regression models are constructed from three equations in which the dependent variables are U.S. flood loss, U.S. hurricane loss and U.S. catastrophe loss. Then two kinds of simulation under two climate change scenarios explore how climate change would affect losses. The climate change scenarios respectively project 13.5% and 21.5% increases in annual precipitation. The first simulation increases only the mean value of annual precipitation; the second simulation assumes that the mean and standard deviation of annual precipitation change in the same proportion. Results show that the growth in reported losses from weather-related natural disasters is due mainly to three socioeconomic factors: inflation, population growth and growth in per capita real wealth. However, weather variables such as precipitation and the number of hurricanes per period also clearly affect losses. The three stage least squares (3SLS) simultaneous equation model shows that a 1% increase in annual precipitation would enlarge catastrophe loss by as much as 2.8%. These findings are suggestive as planning signals to decision makers. 相似文献
312.
A. Bregman F. Arnold V. Bürger H. Fisher J. Lelieveld B. A. Scheeren J. Schneider P. C. Siegmund J. Ström A. Waibel W. M. F. Wauben 《Journal of Atmospheric Chemistry》1997,26(3):275-310
In situ aircraft measurements of O3, CO,HNO3, and aerosol particles are presented,performed over the North Sea region in the summerlower stratosphere during the STREAM II campaign(Stratosphere Troposphere Experiments by AircraftMeasurements) in July 1994. Occasionally, high COconcentrations of 200-300 pbbv were measured in thelowermost stratosphere, together with relatively highHNO3 concentrations up to 1.6 ppbv. The particlenumber concentration (at standard pressure andtemperature) between 0.018-1 m decreased acrossthe tropopause, from >1000 cm-3 in the uppertroposphere to <500 cm-3 in the lowermoststratosphere. Since the CO sources are found in thetroposphere, the elevated CO mixing ratios areattributed to mixing of polluted tropospheric air intothe lowermost extratropical stratosphere. Further wehave used a chemical model to illustrate that nitrogenoxide reservoir species (mainly HNO3) determinethe availability of NOx (=NO + NO2) andtherefore largely control the total net O3production in the lower kilometers of thestratosphere. Model simulations, applying additionalNOx perturbations from aircraft, show that theO3 production efficiency of NOx is smallerthan previously assumed, under conditions withrelatively high HNO3 mixing ratios, as observedduring STREAM II. The model simulations furthersuggest a relatively high O3 productionefficiency from CO oxidation, as a result of therelatively high ambient HNO3 and NOxconcentrations, implying that upward transport of COrich air enhances O3 production in the lowermoststratosphere. Analysis of the measurements and themodel calculations suggest that the lowermoststratosphere is a transition region in which thechemistry deviates from both the upper troposphere andlower stratosphere. 相似文献
313.
Igneous zircon: trace element composition as an indicator of source rock type 总被引:225,自引:2,他引:225