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1.
Natural Hazards - Natural disasters are increasing in frequency in China. Enhancing residents' livelihood resilience and adjusting their livelihood strategies have gradually become effective... 相似文献
2.
There were 407 deaths from wind-related tree failures in the United States, 1995–2007. The most common cause of the deadly
fallen tree was a thunderstorm (41%), followed by nonconvective high winds (35%), tropical cyclones (14%), tornadoes (7%),
and snow and ice (3%). Most (62%) of the deaths were males while the median age was 44 years. The most common location of
the fatality was in a vehicle struck by the tree or a vehicle that crashed into a downed tree on the road (44%), followed
by persons outdoors (38%), in mobile homes (9%), and in frame houses (9%). Persons killed by wind-related tree failures during
tropical cyclones and tornadoes were more commonly at home (40%) when struck than those killed at home by thunderstorm and
nonconvective high winds (13%). Seasonality of the deaths varied by weather type with deaths in thunderstorms clustered during
May–August, nonconvective high winds October–April, tropical cyclones August–October, tornadoes in April and November, and
snow and ice December–April. Regional patterns result from frequency of the wind events, population density, and tree cover.
Suggestions are made for hazard reductions. 相似文献
3.
Motor vehicles historically have been dangerous locations to shelter in during tornado events. Throughout the twentieth century, motor vehicle design has become safer while tornado forecasting has become better understood. Despite such advances, tornado fatalities in motor vehicles still occur today, and some events periodically result in high numbers of deaths (e.g., ten motor vehicle occupants were killed by a single tornado in Garland, Texas, in 2015). We seek to examine all US tornado-induced motor vehicle fatalities documented between 1991 and 2015. Our findings indicate that motor vehicle fatalities have not significantly changed during this study period. We attribute annual fatality totals to persons lacking awareness of impending dangers coupled with numbers of significant tornado events for a given year. We find most fatalities result when vehicles are lofted or passengers are ejected, and this most typically occurs at the EF3–EF5 intensity thresholds. Fatalities that occur at weaker tornado winds (EF0–EF2) are most often attributed to collapsing debris (mostly trees) on vehicles. Spatially, motor vehicle fatalities are greatest in the Deep South and southern Great Plains regions where overall tornado and nighttime tornado frequencies are greatest. Some of the largest motor vehicle fatality events have resulted from tornadoes not being distinctly visible to motorists; such events have been characterized by tornadoes occurring at night or by tornadoes not appearing as “classic funnels.” 相似文献
4.
The results of photometric ( BV RIJHK) and polarimetric ( R)monitoring of the blazar 3C 66A performed at the St. Petersburg State University and the Central AstronomicalObservatory of the Russian Academy of Sciences in 2007–2015, radio observations performed by the Boston University team with the Very Long Baseline Array at 43 GHz, and a gamma-ray light curve based on observations with the Fermi SpaceObservatory are presented. Color variations of the object are studied. Changes in the optical spectral energy distribution are observed at some times, indicating the appearance and disappearance of individual variable sources. A variable source with a degree of polarization of 36% is identified, which is responsible for the polarization variations observed during one episode. The correlations between the variations in the different spectral ranges indicate that the optical and gamma-ray radiation originates near the radio core detected at 43 GHz. The presence of five superluminal components emerging from the core is detected. 相似文献
6.
Evacuations represent an integral aspect of protecting public safety in locations where intense, fast-spreading forest fires
co-occur with human populations. Most Canadian fire management agencies have as their primary objective the protection of
people and property, and all fire management agencies in Canada recommend evacuations when public safety is in question. This
study provides the first national assessment of wildfire-related evacuations in Canada and documents the loss of homes that
coincided with evacuation events. The most striking finding is that despite the intensity and abundance of wildfire in Canada,
wildfires have displaced a relatively small number of people. Between 1980 and 2007, the median number of evacuees and home
losses per year in Canada were 3,590 and 2, respectively. Evacuees’ homes survived in 99.3% of cases. Patterns of evacuations
and home losses reflected the distributions of forests, wildfire, and people across the Canadian landscape. Most evacuations
occurred in boreal areas, which have relatively low population densities but among the highest percent annual area burned
in Canada. Evacuations were less common in southern parts of the country, where most Canadians reside, but individual wildfires
in these areas had significant impacts. Interactions between wildfire and people in Canada exhibited a unique regional pattern,
and within the most densely populated regions of the country they can be considered ‘low-probability, high-consequence’ events.
This Canadian context is fundamentally different from places such as California, where concentrations of fires and people
overlap across large areas and therefore calls for a fundamentally different fire management response. 相似文献
8.
The Massachusetts Water Resources Authority (MWRA) conducts a comprehensive multidisciplinary monitoring program in Massachusetts
Bay, Cape Cod Bay, and Boston Harbor to assess the environmental effects of a relocated secondary-treated effluent outfall.
Through 2007, 8.7 years of baseline data and 7.3 years of postdiversion data (16 total years), including species level estimates
of phytoplankton and zooplankton abundance, have been collected. MWRA’s monitoring program and other studies make this region
one of the most thoroughly studied and well-described marine systems in the world. The data show that the diversion of MWRA
effluent from the harbor to the bay has decreased nutrients concentrations and improved water quality in the harbor (e.g.,
higher dissolved oxygen, lower chlorophyll). The diversion also resulted in an increase in dissolved inorganic nutrients (especially
ammonium) in the vicinity of the bay outfall, but no obvious impacts such as increased biomass or decreased bottom water dissolved
oxygen have been observed. Regional changes in phytoplankton and zooplankton unrelated to the diversion have been seen, and
it is clear that the bays are closely connected both physically and ecologically with the greater Gulf of Maine. Direct responses
to modifications of the nutrient field within a 10 × 10-km area centered near the midpoint of the 2-km long outfall diffuser
in Massachusetts Bay (a.k.a. the nearfield) have not been seen in the plankton community. However, plankton variability in
the bays has been linked to large regional to hemispheric scale (NAO) processes. 相似文献
10.
This paper reports the results of the investigations of 2006–2007 on the distribution and migration forms of artificial radionuclides and chemical elements in the Ob-Irtysh water system. Three regions were studied. One of them is a local segment of the Ob River upstream from the confluence with the Irtysh River; its investigation allowed us to estimate the general radioecological state of the aquatic environment affected by the activity of the Tomsk 7 plant. The second region is a local segment of the Irtysh River upstream from its confluence with the Ob River, where the influence of emissions from the NPO Mayak could be estimated. The third region is the water area of the Ob River after its confluence with the Irtysh River. It characterizes the real level of radioactive and chemical contamination of the middle reaches of the Ob River.In order to explain horizontal variations in the distribution of radionuclides in the upper layer of bottom sediments collected at various sites, the results of sorption-kinetic experiments with radioactive tracers in the precipitate-solution system were used. The investigation of the migration forms of trace elements and radionuclides occurring in river water was based on the method of tangential-flow membrane filtration.Chemical element contents were determined in 400-ml water samples. A set of Millipore polysulfone membranes with pore sizes of 8, 1.2, 0.45, 0.1, and 0.025 μm was employed. Taking into account the ultralow specific concentrations of radionuclides in the water, they were analyzed in 300–500 litre samples using Millipore polysulfone membranes with pore sizes of 0.45 μm and 15 kDa. This allowed us to estimate the percentages of cesium-137 and plutonium-239, 240 in the suspended particulate fraction, colloids, and dissolved species. 相似文献
12.
The study addresses population dynamics in Ghana on the urban and regional levels between 1984 and 2000. At the urban level,
the development trends are analyzed for urban localities (population above 5,000) on the basis of geo-coded census data. Potential
driving forces for rapid population growth related to size, location, accessibility and facility counts are examined using
bivariate and multivariate analysis. An index of weighted accessibility relative to other urban localities provides significant
explanation at the national level, as does initial locality size. At the regional level, population development is analyzed
to provide insight into the rural–urban relations. The level of urbanization is steadily increasing but varies considerably
between regions. Areas of high population growth are found in some rural areas that have a remote location relative to the
large urban centers. This seems to indicate the existence of ‘frontier’ regions, i.e. areas that experience a high degree
of in-migration by people aiming to undertake specific farming activities. A high proportion of the population growth in these
areas appears to take place in relatively small towns. The paper concludes with a more in-depth discussion of the development
characteristics of Ghana’s Western Region. This region has experienced one of the highest regional population growth rates,
mainly due to its status as a ‘frontier’ for cocoa production.
相似文献
13.
The landscapes of the world are constantly changing under the influence of human activities leading to the growth of artificial surfaces. The covering of soil by artificial surfaces is referred to as soil sealing. Aerial and satellite images or data derived from them (for instance CORINE land cover — CLC data used here) provide important information that makes it possible to assess the occurrence, area and rate of soil sealing. As the term sealed soil cannot be wholly identified with the content of the appropriate CLC classes, the term land cover flow urbanization (LCFU) will be used here. The essence of this study is the demonstration and documentation of the trends of the LCFU in Europe for the periods 1990–2000 and 2000–2006 on a single map. This may contribute to a better spatial awareness of the ongoing transformation of landscape under the effects of human activities in an pan-European context. Changes in the LCFU can be seen on a map, compiled from 3 × 3 km squares at an all-European scale, using colours and their hues, to fulfil the role both of identification and classification. The colour method employed makes it possible to perceive three groups of LCFU changes on two time horizons, that is, whether the rate of LCFU in 2000–2006 increased or remained the same (hues of red); or dropped compared to the 1990–2000 period (hues of light to dark blue). The third group represents the LCFU with rates higher or lower than the average (countries with changes recorded in only one time horizon are presented in dark and light magenta colours). 相似文献
14.
We describe contemporaneous changes in environmental quality and social deprivation in English local authority districts over four decades, using secondary source GIS modelled data on environmentally intrusive development. The distribution of this development is described with respect to the Townsend material deprivation score, corroborated against the Breadline Britain index. Spatial patterns of environmental intrusion and material deprivation change markedly over the period, although a clear environmental inequality remains throughout. However, it is not the most deprived who experience the greatest decline in their environmental quality, as most of the increase in environmental intrusion occurs in those districts whose population were amongst the most affluent in the early 1960s. We note that the environmental justice implications of these observations are dependent upon conceptions of justice held, and reflect on the challenge of testing, through empirical longitudinal analysis, the notion that environmental sustainability and social justice are incompatible. 相似文献
15.
We present the results of our study of the classical symbiotic star Z And during its period of activity in 2000–2010. In this
period, the system experienced a series of six outbursts, for three of which high-resolution spectra were obtained and analyzed.
These observations provided information about the system’s behavior during the entire activity period, rather than during
an individual outburst. In particular, we found a fundamental difference between the first outburst, which initiated the activity
period, and subsequent outbursts, namely, the presence of bipolar collimated optical outflows for some of the outbursts. We
propose a model that can explain all the spectroscopic phenomena observed during this series of outbursts, as well as previous
series of outbursts of Z And, and suggest that similar scenarios may be valid for other classical symbiotic stars. 相似文献
16.
The Service d’Observation de la Rade de Villefranche-sur-Mer is designed to study the temporal variability of hydrological conditions as well as the abundance and composition of holo- and meroplankton at a fixed station in this bay of the northwest Mediterranean. The weekly data collected at this site, designated as “Point B” since 1957, represent a long-term time series of hydrological conditions in a coastal environment. Since 2007, the historical measurements of hydrological and biological conditions have been complemented by measurements of the CO 2–carbonic acid system parameters. In this contribution, CO 2–carbonic acid system parameters and ancillary data are presented for the period 2007–2011. The data are evaluated in the context of the physical and biogeochemical processes that contribute to variations in CO 2 in the water column and exchange of this gas between the ocean and atmosphere. Seasonal cycles of the partial pressure of CO 2 in seawater (pCO 2) are controlled principally by variations in temperature, showing maxima in the summer and minima during the winter. Normalization of pCO 2 to the mean seawater temperature (18.5 °C), however, reveals an apparent reversal of the seasonal cycle with maxima observed in the winter and minima in the summer, consistent with a biogeochemical control of pCO 2 by primary production. Calculations of fluxes of CO 2 show this area to be a weak source of CO 2 to the atmosphere during the summer and a weak sink during the winter but near neutral overall (range ?0.3 to +0.3 mmol CO 2 m ?2 h ?1, average 0.02 mmol CO 2 m ?2 h ?1). We also provide an assessment of errors incurred from the estimation of annual fluxes of CO 2 as a function of sampling frequency (3-hourly, daily, weekly), using data obtained at the Hawaii Kilo Nalu coastal time-series station, which shows similar behavior to the Point B location despite significant differences in climate and hydrological conditions and the proximity of a coral reef ecosystem. 相似文献
17.
China is a country prone to high frequency of natural catastrophic events. According to the natural disaster data from 1900 to 2011, the major disaster types include drought, earthquake, epidemic, extreme temperature, flood, mass movement wet and storm. The occurrence of natural disaster and economic loss is increased during the studied period. However, the death toll induced by natural disaster is decreased significantly. A new frame of social development and natural disaster is proposed to discuss the impact of population and GDP on the influence of disaster through the recording and reduction efforts. The results indicated that economic development contributes to the reduction in the impact of natural disaster on the people lives and society. New comprehensive integrated management, including international cooperation, should be established. 相似文献
18.
Natural Hazards - The dual Ahar–Varzaghan earthquakes occurred on August 11, 2012, at 16:53 (Iran standard time) in East Azerbaijan province of Iran. The two quakes measured 6.3 and 6.4 on... 相似文献
19.
This paper characterizes changes in land use and forest cover in southern Cameroon. In doing so, we use remotely sensed data
to define the rates and area of forest loss and cover change in two reference areas over a period of 16 years (from 1984 to
2000)—the Buea-Limbe area in the southwest province and the Bertoua area in the east province. We relate socio-economic data
of these study areas with results from the empirical spatial analysis to explain causes of deforestation. A second set of
explanations, which we call the theoretical perspective, attributes deforestation in southern Cameroon to the intricacies
of modernization, world-systems, and neo-Malthusian theories. 相似文献
20.
Climate risks have significant economic impacts on the various sectors of an economy through direct and indirect channels. When aggregated, their impact can be underestimated or overestimated. This paper examines the impact of five types of climate risks on 47 sectors in China from 2000 to 2014 through the application of a threshold model. We find that: (1) the impact of the integrated climate risks index on sector output is linear. While rainstorms show a U-shaped relationship with output, the other four types of risks—droughts, typhoons, high temperatures and low temperatures freezing—have an inverted U-shaped relationship. (2) Climate risks indirectly influence sector output through capital stock in a significantly positive way. (3) The proportion of intermediate inputs leads to significant differences in the impact of climate risks on sectors. The results suggest that climate policies need to be sector- and risk-specific, as well as dynamic. 相似文献
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