GIS-BASED ANALYSIS OF URBAN LAND-USE CHANGES——A Case Study of Haizhu District of Guangzhou City,China

１INTRODUCTIONMajorcharacteristicsofurbanizationinclude：ur－banconstructioniscontinuouslyspreading，thedemandforurbanlanduseisrapidlyswelling，andalotofa－griculturallandisconvertingintonon－agriculturalland．Whenthesecharacteristicsarereflectedinurbansys－tem，thedevelopingspeedsofbigcitiesandsupercitiesarequickening（CHEN，１９９９）．Basedonthecondi－tionofmarket，landresourcebearsthreetypesofvalueswhicharerespectivelysocialvalue，economicvalueandecologicalvalue．Theexternalexpressiv…     

Source time functions of the 1999, Jiji (Chi-Chi) earthquake from GDSN long period waveform data using aftershocks as empirical Green''''s functions

IntroductionA large earthquake occurred in Jiji (Chi-Chi) town of Nantou County, Taiwan, China at 17h47min on September 20, 1999 (UTC). The origin time was determined to be 17h47min19s of September 20 UTC (1h47min19s of September 21, Beijing Time). The epicenter was determined to be longitude 120.80°E and latitude 23.86°N. It was reported that 2 333 people were killed, 10 002 people were injured, and thousands of houses collapsed which made more than 100 000 people homeless (Shin, e…     

绿色地理学面面观

着色的窗户近一、二年来公众对“环境”越来越感兴趣,每天都有以标题或图片形式反映此类问题的出版物问世。该论题涉及的内容极为广泛,但有一个共同特征,即公众认为环境问题是个大问题,为了人们的康乐而希望克服这些障碍,使世界充满“绿色”。     

Off-Shore Sea Surface Electric Field Investigations around the Indian Sub-Continent during 9-20 May 1983

Sea surface electric field observations off the coast from Goa (15°25'N, 73°47'E) to Madras (13°04'N, 80°15'E) around Sri Lanka, in a distance range 25-135 km from coast, during 9-20 May 1983 were taken. In this paper we have examined the diurnal variation of electric field in the Arabian Sea, Indian Ocean and Bay of Bengal regions covered during the cruise of the research ship ORV Gaveshani. An aspect of electric field dependence on coastal distance and Aitken Nuclei concentration has also been studied. An attempt to examine the latitude dependence of field was also made. Results obtained in the above studies are presented and compared with those obtained elsewhere.     

全球寒武-奥陶系界线划分对比的标志和纽带——中国北方小阳桥剖面的启示

根据对中国小阳桥剖面高精度生物、层序、化学和磁性地层学综合研究的新成果及其与绿岬全球界线层型剖面(GSSP)的详细对比,进一步厘定了加拿大绿岬"金钉子"剖面所定义的奥陶系底界划分与对比的标志,并指出:(1)与所定义的全球标准奥陶系底界相当的界线位于小阳桥剖面块状叠层石灰岩之上19.9 m处的薄层纹层灰岩中(BD-24层...     

Variation of particulate organic carbon and its relationship with bio-optical properties during a phytoplankton bloom in the Pearl River estuary

In this study, variations in the particulate organic carbon (POC) were monitored during a phytoplankton bloom event, and the corresponding changes in bio-optical properties were tracked at one station (114.29°E, 22.06°N) located in the Pearl River estuary. A greater than 10-fold increase in POC (112.29-1173.36 mg m⁻³) was observed during the bloom, with the chlorophyll a concentration (Chl-a) varying from 0.984 to 25.941 mg m⁻³. A power law function is used to describe the relationship between POC and Chl-a, and the POC:Chl-a ratio tends to change inversely with Chl-a. Phytoplankton carbon concentration is indirectly estimated using the conceptual model proposed by Sathyendranath et al. (2009), and this carbon is found to contribute 47.21% (±10.65%) to total POC. The estimated carbon-to-chlorophyll ratio of phytoplankton in diatom-dominated waters is found to be comparable with results reported in the literature. Empirical algorithms for determining the concentrations of Chl-a and POC were developed based on the relationships of these variables with the blue-to-green reflectance ratio. With these bio-optical models, the levels of particulate organic carbon and Chl-a could be predicted from the radiometric data measured by a marine optical buoy, which showed much more detailed information about the variability in biogeochemical parameters during this bloom event.     

Macroinvertebrates in the bed sediment of the Yellow River

Extensive agricultural,industrial and urban development in the Yellow River,China,have modified the sediment-water balance,flow and inundation regimes,longitudinal connectivity,integrity of riparian vegetation,and water quality.Macroinvertebrate assemblages in the bed sediment of main channel and major reservoirs of the Yellow River are described in detail for the first time.A total of 74 taxa comprising 17 taxa of oligochaetes,48 taxa of aquatic insects,5 taxa of molluscs,and 4 taxa of other animals were recorded.A range of feeding guilds were represented,including, collector-gatherers(32 taxa),predators(17 taxa),scrapers(16 taxa),shredders(6 taxa)and collector-filterers(2 taxa).Both the mean density and biomass of macroinvertebrates were significantly higher in sites located in the artificial reservoirs compared with the main river channel. Assemblages varied spatially;Oligochaetes dominated assemblages in upper reaches,insects dominated in middle reaches and other animals(e.g.Crustacea)dominated in lower reaches. Collector-gatherers were dominant throughout the entire river.Classification analysis identified five site-groups on the basis of macroinvertebrate presence/absence:downstream of reservoirs;vegetated sites;reservoir sites;polluted sites,and;lower-reach sites.Lower macroinvertebrate richness,density and biomass,compared with other similar large rivers,were attributed to modification of the sediment-water balance and associated disturbance of benthic habitats.Pollution,stability of sediment and sediment concentration combined to influence the distribution of macroinvertebrates.This knowledge will substantially benefit the recent focus on the health and environmental water requirements of the Yellow River.