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Nirupama Raghavan 《Solar physics》1977,54(2):363-370
Medium resolution observations have been used to find the fractional emitting area in three transition region lines. It is found that is given by DI
mg x
k where k varies from 0.78 to 0.51 in the temperature range 2 × 105 to 7 × 105 K. The average emitting area in O vi deduced by this method is in good agreement with the results from ATM observations. The fractional emitting areas at different values of the Mg x intensity and at different temperatures are combined to find the variation of the areas with height. This variation is in good agreement with Giovanelli's model of the fractional area of cross-section of a magnetic tube of force in the transition region. 相似文献
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Prioritization of disaster risk was carried out for a community in Toronto, Canada. Geographic information systems (GIS) were used for spatial analysis, including spatial overlays and clipping for extracting spatial and attribute information related to people’s vulnerability, critical infrastructure and landuse. In order to determine disaster risk, the overall community vulnerability was evaluated by combining social, economic, physical and environmental vulnerabilities. This paper uses the propane explosion incident as the case in point to demonstrate the methodology and procedure used to evaluate risk using GIS techniques. City of Toronto spatial data have been integrated with the study area to gather landuse information, identify risk zones based on the propane storage facility location and evaluate risks. Statistics Canada 2006 census data have been used for area demographics and people’s social and economic status. Vulnerability indicators were determined based on the GIS-derived spatial and attribute data for the hazard and evacuation zones followed by a quantitative spatial risk estimation and ranking. The methodology of this study, based on the risk evaluation and prioritization conducted, can be applied to future decision making in effective landuse planning and the development of risk management strategies. 相似文献
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The tsunami generated by the December 2004 Sumatra-Andaman earthquake had a devastating effect on some parts of Kerala coast, which is a coast located in southwest India. Results of post-tsunami field surveys carried out to understand the changes in coastal morphology and sediment characteristics in the worst affected Kayamkulam region of Kerala coast are documented in this study. Analysis of offshore bathymetric data indicates the shifting of depth contours towards shore, indicating erosion of sediments and deepening of innershelf due to the tsunami. Depth measurement along the backwater (T-S canal) in the hinterland region indicates siltation due to the inundation of the canal. 相似文献
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Coastal flooding occurs due to storm surges generated by tropical and extra-tropical cyclones on the globe. The meteorological
forcing fields for the generation of storm surges are the tangential surface wind stress on the ocean surface and the normal
atmospheric pressure gradients associated with the weather systems. The large scale forcing from the cyclones is referred
to as the synoptic scale and storm surge prediction from synoptic scale forcing is well developed and is reasonably satisfactory
around the world. However, coastal flooding also occurs from weather systems, with forcing on a meso-scale and also from remote
forcing. It is proposed here that the term “Storm surge” be used to only refer to coastal flooding from synoptic scale forcing
and the terminology “Rissaga” be used for coastal flooding from meso-scale forcing. For flooding due to remote forcing, a
new term “Kallakkadal” is proposed. 相似文献
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The tsunami generated by the December 2004 Sumatra-Andaman earthquake had a devastating effect on some parts of Kerala coast, which is a coast located in southwest India. Results of post-tsunami field surveys carried out to understand the changes in coastal morphology and sediment characteristics in the worst affected Kayamkulam region of Kerala coast are documented in this study. Analysis of offshore bathymetric data indicates the shifting of depth contours towards shore, indicating erosion of sediments and deepening of innershelf due to the tsunami. Depth measurement along the backwater (T-S canal) in the hinterland region indicates siltation due to the inundation of the canal. 相似文献
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Toronto is the largest city in Canada with a population of about 5.5 million in the Greater Toronto Area (GTA). Being located at the shores of Lake Ontario of the Great Lakes, which is the largest surface freshwater system in the world, and affected by air masses originating from the Gulf of Mexico, the Atlantic Ocean, and the Arctic, the city is vulnerable to extreme weather phenomena in socioeconomic and geographical terms. This short paper gives a brief overview of the history of main flooding occurrences in Toronto with an emphasis on the recent flooding of July 2013. An analysis of causes and physical dynamics of the event is presented using the structure of the watersheds and weather systems in the region. Based on the flood risk vulnerability assessment carried out on the 2013 flooding, several weaknesses in critical infrastructure and critical facilities have been highlighted. Future considerations and recommendations include revisiting of the flood damage mitigation strategies (e.g., use of new and adaptive infrastructure designs, social media, crowd-sourcing information), flood zoning update, tax incentives, insurance options, and retrofitting solutions for those living in flood-prone areas. 相似文献
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School buses are important components of the educational structure of societies worldwide. Children’s safety on school bus trips is first and foremost. Decisions made by bus drivers, traffic authorities, school divisions and parents can have a substantial influence. Each year, school buses are used for an estimated 10 billion student trips in the USA. Every school day, 475,000 school buses transport 25 million children to and from schools and school-related activities. Numerous studies have been carried out on school bus and pupil safety during the last 40 years. One important result that has emerged from these studies is that the school bus is the safest mode of transportation for school children. The numbers of accidents, injuries and fatalities show that more school-aged children die in private cars than in school buses. School bus accidents can be either single or multiple vehicle accidents, and the injuries and fatalities are not confined to the occupants of these vehicles but can also include the occupants of other vehicles, pedestrians and bicyclists. This article analyzes school bus accidents in terms of their types, causes and impacts, comparing Canada and the USA. One result that emerges here is that there are more similarities than differences in school bus accidents and the resulting affects. 相似文献
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N. Nirupama 《Natural Hazards》2009,48(1):1-9
Following the devastating tsunami of 26 December 2004 in the Indian Ocean, there was a need to give a voice to the affected
population. Hence a survey was conducted in the tsunami-affected regions of India. The tsunami mainly affected the states
of Tamil Nadu, Kerala and Andhra Pradesh and the Union Territory of Pondicherry, all in south India, as well as the Andaman
and Nicobar Islands of India in the Bay of Bengal. For various logistical reasons, no survey was conducted in the Andaman
and Nicobar Islands. The survey was conducted during 21 January to 19 February 2005 and from 1 March to 8 March 2005. A total
of eight people, arranged into four teams, simultaneously conducted the survey based upon a prepared questionnaire comprising
a total of 16 questions. The total number of villages surveyed was 161, and the overall results of the survey are reported
here. Among many observations, capacity building during the construction process, relocation and housing issues and tsunami
education and awareness were prominent. 相似文献