Spatial patterns of urban land use growth in Beijing   总被引：6，自引：1，他引：6  

Liu Shenghe Ph.D.  Sylvia Prieler  Li Xiubin 《地理学报(英文版)》2002,12(3):266-274

By using digitized land use maps of Beijing in 1982, 1992 and 1997 and employing GIS spatial analysis techniques, this paper conducts an empirical study on the spatial differentiation and spatial patterns of urban land use growth in Beijing in the period of 1982–1997. It is observed that urban land use growth in Beijing went beyond the control of urban planning, in terms of the extraordinary high growth rate and undesired spatial pattern. The rate of urban expansion after 1982, which was predominated by growth of industrial land, was extraordinary high compared to its historical period. While its growth centers have been actively shifting toward the northern part, rather than toward the southern and eastern parts as designated by the latest General Plan (1991–2010) of Beijing, its spatial pattern of urban land use growth in general was in distinct concentric sprawl, which seriously violated the General Plan of Beijing.  相似文献   

Spatial patterns of urban land use growth in Beijing     

LIU Shenghe  Sylvia Prieler  LI Xiubin 《地理学报》2002,12(3):266-274

By using digitized land use maps of Beijing in 1982, 1992 and 1997 and employing GIS spatial analysis techniques, this paper conducts an empirical study on the spatial differentiation and spatial patterns of urban land use growth in Beijing in the period of 1982-1997. It is observed that urban land use growth in Beijing went beyond the control of urban planning, in terms of the extraordinary high growth rate and undesired spatial pattern. The rate of urban expansion after 1982, which was predominated by growth of industrial land, was extraordinary high compared to its historical period. While its growth centers have been actively shifting toward the northern part, rather than toward the southern and eastern parts as designated by the latest General Plan (1991-2010) of Beijing, its spatial pattern of urban land use growth in general was in distinct concentric sprawl, which seriously violated the General Plan of Beijing.  相似文献   

A comparison of biological trends from four marine ecosystems: Synchronies, differences, and commonalities   总被引：1，自引：1，他引：0  

Jason S. Link  William T. Stockhausen  Georg Skaret  William Overholtz  Bernard A. Megrey  Harald Gjster  Sarah Gaichas  Are Dommasnes  Jannike Falk-Petersen  Joseph Kane  Franz J. Mueter  Kevin D. Friedland  Jonathan A. Hare 《Progress in Oceanography》2009,81(1-4):29

Major features of four marine ecosystems were analyzed based on a broad range of fisheries-associated datasets and a suite of oceanographic surveys. The ecosystems analyzed included the Gulf of Maine/Georges Bank in the Northwest Atlantic Ocean, the Norwegian/Barents Seas in the Northeast Atlantic Ocean, and the eastern Bering Sea and the Gulf of Alaska in the Northeast Pacific Ocean. We examined survey trends in major fish abundances, total system fish biomass, and zooplankton biomasses. We standardized each time series and examined trends and anomalies over time, using both time series and cross-correlational statistical methods. We compared dynamics of functionally analogous species from each of these four ecosystems. Major commonalities among ecosystems included a relatively stable amount of total fish biomass and the importance of large calanoid copepods, small pelagic fishes and gadids. Some of the changes in these components were synchronous across ecosystems. Major differences between ecosystems included gradients in the magnitude of total fish biomass, commercial fish biomass, and the timing of major detected events. This work demonstrates the value of comparative analysis across a wide range of marine ecosystems, suggestive of very few but none-the-less detectable common features across all northern hemisphere ocean systems.  相似文献   

Recent climate forcing and physical oceanographic changes in Northern Hemisphere regions: A review and comparison of four marine ecosystems     

K.F. Drinkwater  F. Mueter  K.D. Friedland  M. Taylor  G.L. Hunt Jr.  J. Hare  W. Melle 《Progress in Oceanography》2009,81(1-4):10

As part of a project comparing the structure and function of four marine ecosystems off Norway and the United States, this paper examines the oceanographic responses to climate forcing, with emphasis on recent changes. The four Northern Hemisphere ecosystems include two in the Pacific Ocean (Bering Sea and Gulf of Alaska) and two in the Atlantic Ocean (Georges Bank/Gulf of Maine and the Barents/Norwegian Seas). Air temperatures, wind forcing and heat fluxes over the four regions are compared as well as ocean hydrography and sea-ice conditions where seasonal sea ice is found. The long-term interannual variability in air temperatures, winds and net heat fluxes show strong similarity between adjacent ecosystems and within subregions of an ecosystem, but no significant correlations between Pacific and Atlantic ecosystems and few across the Atlantic. In spite of the lack of correlation between climate forcing and ocean conditions between most of the ecosystems, recent years have seen record or near record highs in air and sea temperatures in all ecosystems. The apparent causes of the warming differ. In the Atlantic, they appear to be due to advection, while in the Pacific temperatures are more closely linked to air-sea heat exchanges. Advection is also responsible for the observed changes in salinity in the Atlantic ecosystems (generally increasing salinity in the Barents and Norwegian Seas and decreasing in the Gulf of Maine and Georges Bank) while salinity changes in the Gulf of Alaska are largely related to increased local runoff.  相似文献   

Geographical accessibility and Kentucky's heart-related hospital services   总被引：2，自引：0，他引：2  

Timothy S. Hare  Holly R. Barcus   《Applied geography (Sevenoaks, England)》2007,27(3-4):181-205

Cardiovascular diseases (CVDs) are a leading cause of mortality in the US. Rates of mortality vary spatially and demographically, influenced not only by individual patient characteristics but also by levels of accessibility to hospital services and facilities. In 2000, Kentucky ranked third in the nation for heart-related deaths. The purpose of this paper is to assess geographical accessibility and service utilization related to ambulatory care sensitive CVDs in Kentucky. This study utilizes the Kentucky Hospital Discharge Database to evaluate service utilization and the Compressed Mortality File to examine mortality related to CVDs. A spatial statistical comparison of the geographical distribution of service usage and travel time to hospitals assists in assessing the relationship between accessibility and health. Our findings suggest that the distribution of utilization and mortality is geographically variable. People living in rural areas travel further to services; populations residing more than 45 min from health facilities are more likely to be socially and economically marginalized. Spatial clustering of high rates of hospital utilization occurs in areas with lower accessibility.  相似文献   

气候变化对中国农业生产的影响   总被引：89，自引：1，他引：88  

唐国平  李秀彬 《地理学报》2000,55(2):129-138

根据１９５８￣１９９７年中国３１０个气象站的月平均最高、最低气温,月平均降水量,日照时数等气象参数分析了中国气候的背影特征。用３个大气环流模型,即ＨａｄＣＭ２、ＣＧＣＭ１、ＥＣＨＡＭ４来模拟未来中国气候变化的情景。同时,建立未来气候变化的６种方案。最后,根据３个ＧＣＭｓ模拟的结果,利用国际应用系统分析研究所（ＩＩＡＳＡ）发展并改进的农业生态地带模型（ＡＥＺ）评估气候变化对中国农业生产的影响。评估主  相似文献   

Parameterization and Micrometeorological Measurement of Air–Sea Gas Transfer     

C. W. Fairaill  J. E. Hare  J. B. Edson  W. McGillis 《Boundary-Layer Meteorology》2000,96(1-2):63-106

Because of the combination of smallconcentrations and/or small fluxes, the determinationof air–sea gas fluxes presents unusual measurementdifficulties. Direct measurements (i.e., eddycorrelation) of the fluxes are rarely attempted. Inthe last decade, there has been an intense scientificeffort to improve measurement techniques and to placebulk parameterizations of gas transfer on firmertheoretical grounds. Oceanic tracer experiments,near-surface mean concentration profiles, eddyaccumulation, and direct eddy covariance methods haveall been used. Theoretical efforts have focusedprimarily in the realm of characterizing the transferproperties of the oceanic molecular sublayer. Recentmajor field efforts organized by the U.S.A. (GASEX-98) andthe European Union (ASGAMAGE) have yielded atmospheric-derivedresults much closer to those from oceanographicmethods. In this paper, we review the physical basisof a bulk-to-bulk gas transfer parameterization thatis generalized for solubility and Schmidt number. Wealso discuss various aspects of recent sensor andtechnique developments used for direct measurementsand demonstrate experimental progress with resultsfrom ASGAMAGE and GASEX-98. It is clear that sensornoise, sensitivity, and cross talk with other speciesand even ship motion corrections still need improvement foraccurate measurements of trace gas exchange over theocean. Significant work remains to resolve issuesassociated with the effects of waves, bubbles, andsurface films.  相似文献   

气候变化对中国农业生产的影响   总被引：1，自引：0，他引：1  

唐国平  李秀彬  Sylvia Prieler 《地理学报》2000,55(5)

根据1958～1997年中国310个气象站的月平均最高、最低气温,月平均降水量,日照时数等气象参数分析了中国气候的背景特征.用3个大气环流模型,即HadCM2、CGCM1、ECHAM4来模拟未来中国气候变化的情景.同时,建立未来气候变化的6种方案.最后,根据3个GCMs模拟的结果,利用国际应用系统分析研究所(IIASA)发展并改进的农业生态地带模型(AEZ)评估气候变化对中国农业生产的影响.评估主要集中于气候变化对不同区域复种指数、可耕种土地面积、潜在粮食产量及其土地生产潜力的影响.  相似文献   

Dust Around Solar Mass Stars     

E.E. Becklin  M. Silverstone  R. Chary  J. Hare  B. Zuckerman  C. Spangler  A. Sargent 《Astrophysics and Space Science》1997,255(1-2):113-118

The DEBRIS project is a search for infrared excess around Sun-like main sequence stars, and other types of stellar targets, using the Infrared Space Observatory. Some results, calibration issues, and changes to our original program are presented. Future platforms for advancing this project after the conclusion of the ISO mission are indicated. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

Ancient wet aeolian environments on Earth: clues to presence of fossil/live microorganisms on Mars     

William C Mahaney  Michael W Milner  David Malloch  Victor R Baker  Trent M Hare 《Icarus》2004,171(1):39-53

Ancient wet aeolian (wet-sabkha) environments on Earth, represented in the Entrada and Navajo sandstones of Utah, contain pipe structures considered to be the product of gas/water release under pressure. The sediments originally had considerable porosity allowing the ingress of living plant structures, microorganisms, clay minerals, and fine-grained primary minerals of silt and sand size from the surface downward in the sedimentary column. Host rock material is of a similar size and porosity and presumably the downward migration of fine-grained material would have been possible prior to lithogenesis and final cementation. Recent field emission scanning electron microscopy (FESEM) and EDS (energy-dispersive spectrometry) examination of sands from fluidized pipes in the Early Jurassic Navajo Sandstone reveal the presence of fossil forms resembling fungal filaments, some bearing hyphopodium-like structures similar to those produced by modern tropical leaf parasites. The tropical origin of the fungi is consistent with the paleogeography of the sandstone, which was deposited in a tropical arid environment. These fossil fungi are silicized, with minor amounts of CaCO₃ and Fe, and in some cases a Si/Al ratio similar to smectite. They exist as pseudomorphs, totally depleted in nitrogen, adhering to the surfaces of fine-grained sands, principally quartz and orthoclase. Similar wet aeolian paleoenvironments are suspected for Mars, especially following catastrophic sediment-charged floods of enormous magnitudes that are believed to have contributed to rapid formation of large water bodies in the northern plains, ranging from lakes to oceans. These events are suspected to have contributed to a high frequency of constructional landforms (also known as pseudocraters) related to trapped volatiles and water-enriched sediment underneath a thick blanket of materials that were subsequently released to the martian surface, forming piping structures at the near surface and constructional landforms at the surface. This constructional process on Mars may help unravel the complex history of some of the piping structures observed on Earth; on Earth, evidence for the constructional landforms has been all but erased and the near-surface piping structures exposed through millions of years of differential erosion and topographic inversion now occur as high-standing promontories. If the features on both Earth and Mars formed by similar processes, especially involving water and other volatiles, and since the piping structures of Earth provided suitable environments for life to thrive in, the martian features in the northern plains should be considered as prime targets for physico/mineral/chemical/microbiological analyses once the astrobiological exploration of the red planet begins in earnest.  相似文献