排序方式： 共有18条查询结果，搜索用时 15 毫秒
11.
12.
13.
14.
15.
16.
Slums are home to a large fraction of urban residents in cities of developing nations, but little attempt has been made to go beyond a simple slum/non-slum dichotomy, nor to identify slums more quantitatively than through local reputation. We use census data from Accra, Ghana, to create an index that applies the UN-Habitat criteria for a place to be a slum. We use this index to identify neighborhoods on a continuum of slum characteristics and on that basis are able to locate the worst slums in Accra. These do include the areas with a local reputation for being slums, lending qualitative validation to the index. We show that slums also have footprints that can be identified from data classified from satellite imagery. However, variability among slums in Accra is also associated with some variability in the land cover characteristics of slums. 相似文献
17.
Kathleen L. McInnes Graeme D. Hubbert Debbie J. Abbs Steve E. Oliver 《Meteorology and Atmospheric Physics》2002,80(1-4):217-233
Summary A coastal ocean model capable of modelling tides, storm surge and the overland flow of floodwaters has been further developed
to include the flux of water from tributaries and the forcing from wave breaking that leads to wave setup in the nearshore
zone. The model is set up over the Gold Coast Broadwater on the east coast of Australia. This complex region features a coastal
lagoon into which five tributaries flow and is subject to flooding from extreme oceanic conditions such as storm surge and
wave setup as well as terrestrial runoff. Weather conditions responsible for storm surge, waves and flooding include cyclones
of both tropical and mid-latitude origin.
Two events are modelled. The first is an east coast low event that occurred in April 1989. This event verified well against
available observations and analysis of the model simulations revealed that wave setup produced a greater contribution to the
elevated water levels than the storm surge. The second case to be modelled was tropical cyclone Wanda, responsible for the
1974 floods. Modelled water levels in the Broadwater were reasonably well captured. Sensitivity experiments showed that storm
surge and wave setup were only minor contributors to the elevated sea levels and their contribution was confined to the earlier
stage of the event before the runoff reached its peak. The contribution due solely to runoff exhibited a tidal-like oscillation
that was 180° out-of-phase with the tide and this was attributed to the greater hydraulic resistance that occurs at high tide.
A simulation of this event with present day bathymetry at the Seaway produced sea levels that were 0.3–0.4 m lower than the
simulation with 1974 bathymetry highlighting the effectiveness of deepened Seaway channel to reduce the impact of severe runoff
events in the Broadwater.
Received October 16, 2001 Revised December 28, 2001 相似文献
18.