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1.
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2.

On May 13, 1996, a disastrous tornado hit the Tangail district of Bangladesh, killing more than 700 people and causing extensive damage to homes, crops, and livestock. This paper explores and analyzes how tornado victims adjusted to this destruction. Data collected from two study sites show that victims received emergency assistance from people both in neighboring areas and from more distant areas, as well as from government agencies and non-governmental organizations (NGOs). At both sites, NGOs played the leading role in minimizing the hardships of victims through extraordinary disaster relief and rehabilitation efforts. Because of the extensive support received, the tornado victims were able to return to their “normal” lives very quickly. This study concludes with several recommendations to help cope with future tornado disasters.  相似文献   

3.
New England and Atlantic Canada are characterized by mixed flood regimes that reflect different storm types, antecedent land surface conditions, and flood seasonality. Mixed flood regimes are known to complicate flood risk analyses, yet the synoptic climatology and precipitation mechanisms that generate annual floods in this region have not been described in detail. We analyzed a set of long-term annual flood records at climate-sensitive stream gauges across the region and classified the synoptic climatology of each annual flood, quantitatively describing the precipitation mechanisms, and characterize flood seasonality. We find that annual floods here are dominantly generated by Great Lakes-sourced storms and Coastal lows, known locally as ‘nor’easters.’ Great Lakes storms tend to be associated with lower magnitude annual floods (<75th percentile) and Coastal lows are more clearly associated with higher magnitude events (>75th percentile). Tropical cyclones account for few of all annual floods, including extreme events, despite causing some of the region’s largest and most destructive floods. Late winter/early spring is when the greatest number of annual floods occur region wide, and rainfall is the dominant flood-producing mechanism. Rainfall in combination with snowmelt is also important. Both mechanisms are expected to be impacted by projected regional climate change. We find little evidence for associations between flood-producing synoptic storm types or precipitation mechanisms and large-scale atmospheric circulation indices or time periods, despite upward trends in New England annual flood magnitudes. To more completely investigate such associations, partial duration flood series that include more floods than just the largest of each year, and their associated synoptic climatologies and precipitation mechanisms, should be analyzed.  相似文献   

4.
Although tornadoes are microscale meteorological features, their occurrence is linked to the larger synoptic-scale environment. Most conceptual models of synoptic situations that give rise to tornadoes are based on conditions prevalent in the Great Plains of the United States. However, tornadoes develop in many different synoptic environments, particularly when they form beyond the boundaries of “Tornado Alley.”

Tornado occurrences in the state of Virginia are identified from 1951 through 1992. Using upper air data for the nearest site and observation time, a synoptic classification is produced via application of principal components analysis and cluster analysis. The five resulting synoptic classes each exhibit distinctive thermodynamic and flow conditions that serve as air-mass paradigms for tornado occurrence in Virginia. The groups include thermodynamic/northwest flow air masses, a mixed thermodynamic/dynamic category, a polar front jet situation, cool season midlatitude cyclone events, and Great Plains type tornadic air masses. A sixth type, tornadoes spawned by tropical systems, is defined separately.

A variety of indices have been developed by forecasters to provide information about the likelihood of severe weather and tornadic activity. The lifted index, K-index, Showalter index, SWEAT, Totals index, and a wind shear index are calculated for each tornado event. Analysis of variance indicates that most of these indices are statistically different between synoptic classes.

These results suggest that the synoptic-scale mechanisms responsible for tornado occurrence in the mid-Atlantic states are quite variable. Enhanced predictive capability could be gained by considering the prevailing synoptic conditions associated with individual storms. [Key words: synoptic climatology, tornadoes, Virginia, classification, severe weather.]  相似文献   

5.
Abstract

This paper examines the use of land and property information systems by local authorities in England and Wales. A number of important lessons for the future are discussed. There is much evidence which suggests that the primary use of land and property information systems is to support administrative tasks. This is an important conclusion when it is borne in mind that, in early days of discussions on the design of land and property information systems, it was envisaged that most of the output from such systems would be for management  相似文献   

6.
Immediately following the May 2011 tornado, the city of Joplin, Missouri, initiated recovery efforts to rebuild the part of the community devastated by this event. In doing so, city officials introduced two new safety measures and recommended several others. The main objective of this paper is to explore the tornado survivors' compliance with the safety features recommended by the Joplin city authorities. Face‐to‐face interviews, as well as other methods, were used to survey respondents who were living within the tornado path (damage zones) at the time of the tornado. Results showed that 43 percent of all respondents implemented at least one recommended tornado measure in rebuild or repair their destroyed/damaged homes. Further, it was found that three variables considered here— rebuild or repair, damage zone category, and perceived tornado risk—were all significant contributors to a homeowner's decision to implement recommended tornado safety measures. The paper concludes with a recommendation for expanding tornado safety education among the respondents.  相似文献   

7.
The frequency and timing of Holocene paleofloods in the hilly terrain of New Hampshire and Maine are identified using 14C and high-resolution (cm-by-cm) particle size analysis of sediment cores taken from six post-glacial lakes (~0.1–1.4 km2). A total of nine sediment cores (4.5–6 m long) were taken near the base of stream delta foreslopes. End-member modeling of the particle-size frequency distributions from each core produces 3–5 representative end member distributions, or end members (EMs). Concurrent increases in mean and median particle size, and in the relative abundance of the coarsest EM(s), indicate increased transport capacity of inflowing tributaries, resulting from rainstorms. In all 9 cores, particle size data show clear signs of episodic, high-energy sediment transport events where proxy measurements such as loss-on-ignition and magnetic susceptibility do not, demonstrating the sensitivity of particle size analysis in paleostorm investigations made using lake sediment cores. Floods caused by storms in this region peaked around 1.4, 2.1, 3.0, 3.9, 6.8, 8.2, and 11.5 ka cal BP, and presently appear to be increasing in frequency. Periods of storminess in New Hampshire and Maine correlate well with other records of precipitation and climate in the northeastern United States during the Holocene, further supporting modern records which show tropical air masses as a primary driver of extreme precipitation events in New England (Ludlum 1996; Konrad 2001; Sisson and Gyakum 2004).  相似文献   

8.
Landslides triggered by rainfall are the cause of thousands of deaths worldwide every year. One possible approach to limit the socioeconomic consequences of such events is the development of climatic thresholds for landslide initiation. In this paper, we propose a method that incorporates antecedent rainfall and streamflow data to develop a landslide initiation threshold for the North Shore Mountains of Vancouver, British Columbia. Hydroclimatic data were gathered for 18 storms that triggered landslides and 18 storms that did not. Discriminant function analysis separated the landslide-triggering storms from those storms that did not trigger landslides and selected the most meaningful variables that allow this separation. Discriminant functions were also developed for the landslide-triggering and nonlandslide-triggering storms. The difference of the discriminant scores, ΔCS, for both groups is a measure of landslide susceptibility during a storm. The variables identified that optimize the separation of the two storm groups are 4-week rainfall prior to a significant storm, 6-h rainfall during a storm, and the number of hours 1 m3/s discharge was exceeded at Mackay Creek during a storm. Three thresholds were identified. The Landslide Warning Threshold (LWT) is reached when ΔCS is −1. The Conditional Landslide Initiation Threshold (CTLI) is reached when ΔCS is zero, and it implies that landslides are likely if 4 mm/h rainfall intensity is exceeded at which point the Imminent Landslide Initiation Threshold (ITLI) is reached. The LWT allows time for the issuance of a landslide advisory and to move personnel out of hazardous areas. The methodology proposed in this paper can be transferred to other regions worldwide where type and quality of data are appropriate for this type of analysis.  相似文献   

9.
Abstract:   Coastal research and monitoring on New Zealand beaches have typically examined seasonal and event-driven (storms) changes in the coast. However, historical records are now of sufficient length to indicate that change occurs at longer timescales. This paper presents examples of multi-decadal change at three case-study locations around New Zealand. Results show that morphological adjustment of the coast occurs at multi-decadal scales and is much larger than short-term dynamics. Physical mechanisms driving changes are ill defined but may be associated with El Niños and La Niña episodes which modulate waves and sea level, as well as changes in sediment supply.  相似文献   

10.
《The Journal of geography》2012,111(3):150-156
Abstract

The geography of Black America represents a legitimate and a distinctive sub-field of the discipline. While research time and attention is being focused increasingly on Black America much remains to be done to incorporate its study into introductory courses at both the secondary and college levels. Since many existing geography courses are inadequately structured to accommodate a meaningful analysis of Black America, it will be necessary to restructure them so that they become relevant not only to Black America but to emerging world-wide cultural patterns as well. The most logical and efficacious framework for such courses is one focused on the geography of cities. Courses dealing with urban topics can be devised so that major concepts of city structure can be presented as concomitants to topics dealing with the role and the contribution of the Negro in the city.  相似文献   

11.
This study integrates past research methodologies, data from the National Lightning Detection Network (NLDN), and geographic information system techniques to assess the lightning and severe weather hazard relationship for the 27–28 April 2011 United States tornado outbreak. NLDN and Doppler radar data are used to examine the cloud-to-ground (CG) lightning characteristics associated with seven supercell thunderstorms that produced long-track, significant and/or violent tornadoes. Analyses indicate that CG lightning flashes alone do not provide enough information for the detection of a lightning jump prior to tornadogenesis. All seven supercells were dominated by negative-polarity CG lightning flashes; which is expected due to the geographic location and elevated low-level moisture found in the outbreak environment. The correlation between low-level mesocyclone strength and total CG lightning flash rate was varied and inconsistent among all storms despite their formation and sustenance in similar environmental and geographic space. Additional case studies, as well as climatological approaches, are required to discover if the varying lightning–tornado relationships found in this study are consistent with other tornadic environments.  相似文献   

12.
Abstract

This article introduces the word “LAMPPOST” as a mnemonic device to aid in the instruction of climate variables. It provides instructors with a framework for discussing climate patterns that is based on eight variables: latitude, altitude, maritime influence and continen-tality, pressure systems, prevailing winds, ocean currents, storms, and topography. It focuses on ways to introduce the variables in a logical sequence that provides a smooth transition from one variable to the next. It is primarily designed for instructors with a background in human geography or the social sciences who wish to incorporate elements of physical geography into their lectures.  相似文献   

13.
SUMMARY

The greatest deficiency in American geography is substantive research leading to scholarly publication. By comparison, teaching much more adequately developed so that the need for improvement there is not so urgent. I am convinced however that a majority American geographers respect scholarship and are eager to see improved in quantity and quality.

One of the chief obstacles to the initiation of active research programs by many geographers is a poor development of a sense of problem.

An important stimulation to the development of personal research programs would be the organization of geographical meetings of relatively small size in which active rsesearch workers reported on their progress and findings. Emphasis could be on exchange of ideas, debating of controversial issues and the development of research programs rather than upon the reading of formal papers. Instructors in small colleges and high schools could be inspired to undertake local research problems so that they become expert on heir local areas. This was characteristic of such teachers in Japan.

Our national professional organization, including i t s annual meetings, has become so large that such a n intimate program involving ritical discussion is difficult to attain.

Up to the present time the regional divisions have not developed a consistently distinctive and important function in the national organization. Their usefulness is not comonensurate with the degree of representation which they at present have on the Council of the AAG.

It is my hope that the regional divisions may see fit to undertake this function of stimulating personal and group research as t heir main function and plan their annual meetings accordingly. I do not propose to blueprint these meetings too precisely, but I will go so far as to say that in my judgment they should be occasions for mental stretching. They shoufd be pitched at a high level so that they will attract mature minds and seriousscholars. The total effect of such meetings should be to toughen intellectually those in attendance through providing opportunities for professional debate and discussion. I would make every effort to encourage participation in these programs by both youngsters and old sters, by alert high school teachers and those in college and university faculties so that the lifting effects of the regional meetings would be felt throughout all ranks and ages. I would favor the development of field excursions provided they are planned with genuine professional values in mind; values not limited to observation alone but focused so as to stimulate controversy and healthy debate.  相似文献   

14.
The tornado siren has become the standard method of notifying resident populations of dangerous weather conditions. In March, 2012, the city of San Marcos, Texas purchased 14 Tempest-121 rotating sirens creating a coverage network. Because San Marcos has experienced two tornadoes during the previous twelve years, two research questions were constructed, 1) what is the spatial coverage of the tornado siren network in San Marcos, and 2) what is the approximate number of residents located outside the siren's network coverage area? The hypothesis stated that the siren network left more than 10 percent of the population outside the coverage area.Each tornado siren was individually located and associated GPS data allowed for construction of the siren network in a GIS. The analysis identified approximately 26 percent (22 km2) of San Marcos located outside the network's coverage area. Furthermore, analysis of census block data and the extent of siren coverage resulted in 5.14 percent of residents not included in siren coverage, approximately half compared to what was hypothesized. As San Marcos continues to expand, both in size and in population, the question of whether there is enough coverage for the entire city for the foreseeable future remains unclear.  相似文献   

15.
《Basin Research》2018,30(Z1):36-47
Radioisotope geochronology of detrital grains coupled with quantitative classification of grain morphology can provide valuable insight into the history of sediment transportation and recycling. Here we present ca. 750 new concordant U‐Pb ages from detrital zircon grains from a relatively understudied Permian sedimentary succession in the New England Orogen (eastern Australia), coupled with values of abrasion that provides a proxy for the relative source‐to‐sink distance. We show that cumulative proportion curves for age groups that correspond to plausible source regions provide insights into the palaeodrainage, even if the basin stratigraphy is relatively poorly constrained. This approach is particularly suitable for investigating complex depositional systems that received inflow from different provenance, such as back‐arc and intra‐cratonic basins. Using the example from eastern Australia, our results show that during the Early Permian, a large regional fluvial system transported detritus from continental Gondwana across the landscape of the former active continental margin (New England Orogen) and the simultaneously developing East Australian Rift System. In addition, a local drainage system mobilised detritus within the New England Orogen. Our new constraints for the Early Permian palaeogeography support the idea that the Lower Permian successions of the southern New England Orogen were deposited in a back‐arc region that was likely linked to a retreating subduction zone.  相似文献   

16.
We tested the use of cladoceran remains as a proxy for the presence and life history type of alewife (Alosa pseudoharengus) from pre-colonial times to present in a group of coastal lakes in southern New England. Alewife are a keystone predator that structure the zooplankton community through strong predation on large-bodied zooplankton species, which releases small zooplankton species, such as Bosmina spp., from competition and predation pressure. In southern New England there are lakes without alewife, lakes with anadromous alewife that only reside in lakes during the summer, and lakes with landlocked alewife that reside in lakes year-round. The entire zooplankton community of these lakes is structured differently based on the presence and type of alewife they contain. We examined differences in the morphology of Bosmina spp. from sediment core samples and contemporary zooplankton samples between lakes with different types of alewife. We found that there were significant differences in the morphology of Bosmina spp. between lakes with and without alewife. We also used discriminant analysis on the morphology of Bosmina spp. to classify lakes in terms of alewife presence and alewife type. We found that the morphology of Bosmina spp. can serve as a useful proxy for detecting the presence, but not the life history type of alewife from paleoecological and contemporary inferences.  相似文献   

17.
The sustainable management of erodible pastoral hill country is a major focus of land use research in New Zealand. A multi-disciplinary study, using a high resolution lake sedimentation record, is being conducted to determine the role that cyclonic storms and natural and human-induced vegetation changes play in the erosion history of a landslide-prone hill country watershed.Sediment cores from Lakes Tutira and Waikopiro in northern Hawke's Bay were analysed to construct the magnitude-frequency history of storm-induced erosion since European settlement. Pulses of sediment representing individual storms can be clearly identified and are correlated to a storm history derived from analysis of a 93 year daily rainfall record. Correlation and dating are confirmed by pollen and diatom analysis,137Cs distribution, tephrochronology and reference to a well documented land use history. Annually laminated, organic rich deposits, which occur in the uppermost sediments and represent the annual decomposition of biogenic material associated with eutrophication, are also used to confirm the chronology.A high correlation was found between storm sediment thickness and total storm rainfall (R2=0.8). Although sediment producing storms (>150 mm) occur on a near annual basis, the two largest storms (>600 mm) contributed 54% of the total sediment thickness.The presence of well defined storm sediment pulses has enabled the lake storage component of a sediment budget to be calculated for Cyclone Bola (1988), the most recent and largest rainstorm on record. The integration of this budget with the storm-magnitude-frequency history will be used to develop watershed-based models to predict the impacts of land use changes and the erosion response to climate scenarios.This is the third paper in a series of papers published in this issue on high-resolution paleolimnology. These papers were presented at the Sixth International Palaeolimnological Symposium held 19–21 April, 1993 at the Australian National University, Canberra, Australia. Dr A. F. Lotter and Dr. M. Sturm served as guest editors for these papers.  相似文献   

18.
Analysis of data collected between 1950 and 1995 in the state of Indiana indicates that the state experiences an average of nearly 19 tornadoes each year, which occur on approximately 8 or 9 days during an average year. Analysis of storm dimensions indicates that the annual probability of a point location in Indiana being impacted by a tornado is 1.4 × 10-4 per year. The largest number of the more intense tornadoes (F2 and higher) typically occur from March to June, during the afternoon and evening, although tornadoes have been observed in each month of the year and each hour of the day. Inter-annual variability of tornadic events in Indiana is large and may reflect both physical causes (e.g., the variability of cyclone passages or jet stream location) and recording bias (e.g., increased public awareness during the 1950s). Using the data set from Indiana, statistical analyses of the temporal and spatial variability of tornadoes are undertaken. Analyses of tornado reports by county indicate that, in addition to area and population, surface roughness is a significant determinant of event frequency. Analyses presented herein also indicate that in contrast to previous studies, (1) no statistically significant hebdomadal cycle of tornado reporting is evident in the data and (2) the diurnal cycle of tornado records is evident for all F-scale classes and is not confined largely to the weak tornado categories. Analyses of the physical dimensions and F-scale ratings of tornadoes in Indiana indicate that there has been a decline in reported tornado intensity, width, and length between 1950 and 1995. These changes are in accord with evidence of a decreasing number of reports of strong and violent tornadoes across the United States over this period and appears to be principally a result of reporting biases at the beginning of the record. [Key words: tornado climatology, temporal and spatial variability, reporting bias.]  相似文献   

19.

Analyses of the geography of British elections have typically stressed the continuity in patterns of party support. This paper challenges that conclusion. Employing an alternative method of analysis, it identifies significant regional trends in the Conservative and Labour vote between 1950 and 1983. Pro-Labour trends in Scotland and Northwest England are contrasted with secular changes favoring the Conservatives in non-metropolitan Southern England. These long-term trends have not been associated with growing regional polarization in party support. While the findings are specific to Britain, the method of assessing electoral change might be usefully applied to patterns in other countries.  相似文献   

20.
《The Journal of geography》2012,111(7):330-333
Abstract

Sidney Licht (ed.). Medical Climatology. Elizabeth Licht Publishers, New Haven, Conn., 1964. xix and 753 pages, with tables, maps, diagrams and index. $16.00.

Allen K. Philbrick. This Human World. John Wiley and Sons, Inc., New York, 1963. xii and 500 pages, illustrated, maps, tables, appendix, index. $7.95.

Winston W. Crouch and Beatrice Dinerman. Southern California Metropolis: A Study in Development of Government for a Metropolitan Area. University of California Press, Berkeley, 1963. $7.50.

Samuel N. Dicken and Forrest R. Pitts. Introduction to Human Geography. Blaisdell Publishing Co., New York, 1963. 468 pages. $9.75.

Allan G. Bogue. From Prairie to Corn Belt. University of Chicago Press, Chicago, 1963. 310 pages with table of contents, maps, diagrams, bibliography, and index. $6.95.

Eric P. Kelly and Dragos D. Kostick. The Land and People of Poland. Portraits of the Nations Series. J. B. Lippincott Company, Philadelphia, New York, 1964. 128 pp., map and many illustrations. $2.93.  相似文献   

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