THE SPATIAL SURFACE OF POVERTY IN PENINSULAR MALAYSIA     

Peggy Teo Cheok Chin  M.Sc.  Ph.D. 《Singapore journal of tropical geography》1990,10(1):55-73

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Complex study of characteristics of a Cb cloud developing over the arabian peninsula under conditions of high dew point deficit in the atmosphere. Part 2. Analysis of the meteosat data     

T. W. Krauss  A. A. Sin’kevich  N. E. Veremei  Yu. A. Dovgalyuk  V. S. Makitov  V. D. Stepanenko 《Russian Meteorology and Hydrology》2011,36(3):167-174

Development of a long-living Cb cloud in the desert part of Saudi Arabia on April 10, 2008 is analyzed. Continuous satellite and radar observations of the cloud are carried out during five hours. Numerical modeling of the cloud is performed using a nonstationary 1.5-dimensional model. Data on the Cb cloud and its anvil development dynamics are obtained. It is shown that the anvil characteristics differ significantly in the zone of its formation directly over the cloud and when moving away from it. It is pointed out that the radar underestimates the anvil sizes. Estimation of precipitation rate from the cloud under study by means of satellite and radar measurements is compared against the results of numerical modeling. It is found that precipitation rate could reach 100 mm/h. The radar estimates of the precipitation rate are significantly overstated, which is, in this case, due to presence of large hail particles.  相似文献   

Impacts of landscape fragmentation on simulated precipitation fields in the Amazonian sub-basin of Ji-Paraná using the Eta model     

Daniel Andres Rodriguez  Sin Chan Chou  Javier Tomasella  Eleonora M. C. Demaria 《Theoretical and Applied Climatology》2014,115(1-2):121-140

Numerical studies on impacts of landscape fragmentation due to land use and land cover change (LUCC) on precipitation fields over the Ji-Paraná basin in the Amazon region are carried out using atmospheric Eta model. Experiments consider historical data about LUCC over the basin from 1978 to 2000 and compare simulations under LUCC conditions with simulations under pristine conditions. In agreement with previous observational studies, model results do not show statistically significant impacts on precipitation in the region. Results indicate that variability in precipitation in this region is mainly controlled by large-scale atmospheric characteristics and soil moisture conditions. However, some limitations are identified in the model simulations, mainly associated to the diurnal cycle of precipitation.  相似文献   

Retracted: Discussion of paper ‘Development of a family of unconditionally stable explicit direct integration algorithms with controllable numerical energy dissipation’ by Chinmoy Kolay and James M. Ricles,Earthquake Engineering and Structural Dynamics 2014; 43:1361–1380          下载免费PDF全文

Shuenn‐Yih Chang 《地震工程与结构动力学》2015,44(8):1325-1328

It seems that the explicit KR‐α method (KRM) is promising for the step‐by‐step integration because it simultaneously integrates unconditional stability, explicit formulation, and numerical dissipation together. It was shown that KRM can inherit the numerical dispersion and energy dissipation properties of the generalized‐α method (GM) for a linear elastic system, and it reduces to CR method (CRM) if ρ_∞ = 1is adopted, where ρ_∞ is the spectral radius of the amplification matrix of KRM as the product of the natural frequency and the step size tends to infinity. However, two unusual properties were found for KRM and CRM, and they might limit their application to solve either linear elastic or nonlinear systems. One is the lack of capability to capture the structural nonlinearity, and the other is that it is unable to realistically reflect the dynamic loading. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Synoptic patterns associated with landslide events in the Serra do Mar, Brazil   总被引：2，自引：1，他引：1  

Marcelo E. Seluchi  Sin Chan Chou 《Theoretical and Applied Climatology》2009,98(1-2):67-77

Heavy rains frequently occur over the Serra do Mar, in the southeast coastal mountain region in Brazil, particularly during the summer season. These rains can cause landslides and loss of life. The objective of this work is to produce a synoptic climatology of heavy rainfall episodes of the period from November to April using 10-year reanalyses data. The identification of the synoptic pattern of these events should provide guidance to forecasters. The landslide events were mostly related to cold front passages and the South Atlantic Convergence Zone (SACZ). These systems differed from the climatology by exhibiting more intense characteristics for the frontal situations and a blocking circulation configuration for the SACZ situations. In both cases, the composite fields showed that the 250-hPa mass divergence was strikingly more intense than the climatology and had a preferred location in the 24 h prior to landslide events. Anomalies of this ten-year event climatology showed above-normal moisture anomalies, which are more evident in the SACZ than in the frontal cases.  相似文献   

Climate downscaling over South America for 1961–1970 using the Eta Model     

José Fernando Pesquero  Sin Chan Chou  Carlos Afonso Nobre  José Antonio Marengo 《Theoretical and Applied Climatology》2010,99(1-2):75-93

This study shows the results from a regional climate simulation of the present-day climate, corresponding to the period 1961–1970 over South America, using the regional Eta Model nested within the HadAM3P model from the UK Hadley Centre. The simulation analysis is focused on assessing the capability of the nested regional model in representing spatial patterns of seasonal mean climate and the annual cycle of precipitation and temperature. The goals of this 10-year run for South America are to verify if the Eta Model can be used in climate-change scenarios and to verify if this model has the ability to generate added value for the South American continent. The Eta Model was chosen because there are few investigations using the Eta Model for long integrations over South America and because the vertical coordinate system used in this model is recommended for use over South America due to the presence of the Andes range. In the present 10-year simulation, the regional model reproduced many of the South American mesoscale climate features and together added new value to the driver model. Value was also added to the driver model by reducing seasonal biases in austral winter relative to austral summer. The regional model also exhibits better performance in the representation of low-level circulation, such as the topographically induced northwesterly flux.  相似文献   

Development of regional future climate change scenarios in South America using the Eta CPTEC/HadCM3 climate change projections: climatology and regional analyses for the Amazon, S?o Francisco and the Paraná River basins     

Jose A. Marengo  Sin Chan Chou  Gillian Kay  Lincoln M. Alves  José F. Pesquero  Wagner R. Soares  Daniel C. Santos  André A. Lyra  Gustavo Sueiro  Richard Betts  Diego J. Chagas  Jorge L. Gomes  Josiane F. Bustamante  Priscila Tavares 《Climate Dynamics》2012,38(9-10):1829-1848

The objective of this study is to assess the climate projections over South America using the Eta-CPTEC regional model driven by four members of an ensemble of the Met Office Hadley Centre Global Coupled climate model HadCM3. The global model ensemble was run over the twenty-first century according to the SRES A1B emissions scenario, but with each member having a different climate sensitivity. The four members selected to drive the Eta-CPTEC model span the sensitivity range in the global model ensemble. The Eta-CPTEC model nested in these lateral boundary conditions was configured with a 40-km grid size and was run over 1961–1990 to represent baseline climate, and 2011–2100 to simulate possible future changes. Results presented here focus on austral summer and winter climate of 2011–2040, 2041–2070 and 2071–2100 periods, for South America and for three major river basins in Brazil. Projections of changes in upper and low-level circulation and the mean sea level pressure (SLP) fields simulate a pattern of weakening of the tropical circulation and strengthening of the subtropical circulation, marked by intensification at the surface of the Chaco Low and the subtropical highs. Strong warming (4–6°C) of continental South America increases the temperature gradient between continental South America and the South Atlantic. This leads to stronger SLP gradients between continent and oceans, and to changes in moisture transport and rainfall. Large rainfall reductions are simulated in Amazonia and Northeast Brazil (reaching up to 40%), and rainfall increases around the northern coast of Peru and Ecuador and in southeastern South America, reaching up to 30% in northern Argentina. All changes are more intense after 2040. The Precipitation–Evaporation (P–E) difference in the A1B downscaled scenario suggest water deficits and river runoff reductions in the eastern Amazon and S?o Francisco Basin, making these regions susceptible to drier conditions and droughts in the future.  相似文献   

Habitat use and movement of the mummichog (<Emphasis Type="Italic">Fundulus heteroclitus</Emphasis>) in a restored salt marsh     

S.?L.?H.?Teo  K.?W.?AbleEmail author 《Estuaries and Coasts》2003,26(3):720-730

The mummichog,Fundulus heteroclitus, is one of the most abundant macrofaunal components of salt marsh ecosystems along the east coast of the United States. During April–November 1998, we determined the habitat use and movement patterns of young-of-the-year (YOY) and adult mummichogs in a restored marsh, formerly a salt hay farm, and an adjacent creek in order to expand our understanding of the ecology of the species and evaluate the success of the restoration. Four major fish habitat types (large first-order natural creek, second-order created creek, linear drainage ditch, and marsh surface) were identified within the study site. Patterns of relative abundance and mark and recapture using coded wire tags were used to determine the habitat use, tidal movements, home range, and site fidelity of the species within these habitat types. A total of 14,784 fish, ranging from 20–100 mm SL, were captured with wire mesh traps and tagged, and 1,521 (10.3%) fish were recaptured. A variety of gears were used to attempt to recapture fish across all habitat types, including wire mesh traps, push nets, and otter trawls. Based on abundance and recaptures of tagged fish, the YOY and adults primarily used the shallow subtidal and intertidal areas of the created creek, the intertidal drainage ditches, and the marsh surface of the restored marsh but not the larger, first-order natural creek. At low tide, large numbers were found in the subtidal areas of the created creek; these then moved onto the marsh surface on the flooding tide. Elevation, and thus hydroperiod, appeared to influence the microscale use of the marsh surface. We estimated the home range of adults and large YOY (20–100 mm SL) to be 15 ha at high tide, which was much larger than previously quantified. There was strong site fidelity to the created creek at low tide. The habitat use and movement patterns of the mummichog appeared similar to that reported for natural marshes. Coupled with the results of other studies on the feeding, growth, and production of this species in this restoreh, the species appeared to have responded well to the restoration.  相似文献   

The Interpretation of Segregation Indices in Context: The Case of P in Singapore     

Chih Hoong Sin 《The Professional geographer》2002,54(3):422-437

The article argues that the interpretation of segregation indices has been deeply conditioned by U.S. and U.K. studies. Using an empirical example of the P index on data pertaining to Singapore's public housing residents, the article investigates the “exposure” dimension of segregation for Singapore's three main ethnic groups: Chinese, Malay, and Indians/Others. While the figures yielded are low in comparison to those in Western studies, the article demonstrates that low index values are nonetheless sociologically significant. The figures generated for Malay isolation in higher–quality public housing were argued to be qualitatively different from those for Indian isolation in lower–quality public housing. The former demands an appreciation of household structure and kinship ties, while the latter involves atomized individuals in a highly urbanized setting. Blind application and interpretation of indices run the risk of coming to erroneous conclusions. A contextual approach is needed for a better appreciation of the diverse ways in which segregation is manifested and experienced.  相似文献   

Structural changes and oxidation of ferroan phlogopite with increasing temperature: in situ neutron powder diffraction and Fourier transform infrared spectroscopy     

Chul-Min Chon  Chul-Kyoo Lee  Yungoo Song  Sin Ae Kim 《Physics and Chemistry of Minerals》2006,33(5):289-299

The thermal response of the natural ferroan phlogopite-1M, K₂(Mg_4.46Fe_0.83Al_{0. 34}Ti_0.22)(Si_5.51Al_{2. 49})O₂₀[OH_3.59F_0.41] from Quebec, Canada, was studied with an in situ neutron powder diffraction. The in situ temperature conditions were set up at ?263, 25, 100°C and thereafter at a 100°C intervals up to 900°C. The crystal structure was refined by the Rietveld method (R _p=2.35–2.78%, R _wp=3.01–3.52%). The orientation of the O–H vector of the sample was determined by the refinement of the diffraction pattern. With increasing temperature, the angle of the OH bond to the (001) plane decreased from 87.3 to 72.5°. At room temperature, a = 5.13 Å, b = 9.20 Å, c = 10.21 Å, β = 100.06° and V(volume) = 491.69 ų. The expansion rate of the unit cell dimensions varied discontinuously with a break at 500°C. The shape of the M-octahedron underwent some significant changes such as flattening at 500°C. At temperatures above 500°C, the octahedral thickness and mean distance was decreased, while the octahedral flattening angle increased. Those results were attributed to the Fe oxidation and dehydroxylation processes. The dehydroxylation mechanism of the ferroan phlogopite was studied by the Fourier transform infrared spectroscopy (FTIR) after heated at temperatures ranging from 25 to 800°C with an electric furnace in a vacuum. In the OH stretching region, the intensity of the OH band associated with Fe²⁺(N _B-band) begun to decrease outstandingly at 500°C. The changes of the IR spectra confirmed that dehydroxylation was closely related to the oxidation in the vacuum of the ferrous iron in the M-octahedron. The decrease in the angle of the OH bond to the (001) plane, with increasing temperature, might be related to the imbalance of charge in the M-octahedra due to Fe oxidation.  相似文献