ANALYSIS OF THE ENVIRONMENT FEATURE OF BREEDING AREA AND ENDANGERED FACTORS OF RED-CROWNED CRANE IN CHINA

1 POPULATION STATUS AND DISTRIBUTION OF RED-CROWNED CRANE IN CHINAAccording to aerial survey, the number of Red-crowned Crane(Grus japonensis) is about 700 in breeding areas of China in 1981－1984, accounting for 65％of total numbers in the world (LI et al., 1987; MAet al., 1987; MA, 1987; FENG et al., 1985). In August 1992, the international symposium of crane in the world was convened in Calgary, Canada. The number of the crane was estimated accurately. There w…     

Directional Spectrum of Wind Waves: Part Ⅰ- Model and Derivation

1　Introduction　Numerousinvestigationsondeepwaterwindwavespectrumhavebeen performed (Phillips ,195 8;Bretschneider,195 9;PiersonandMoscowitz ,196 4;Hasselmannetal.,1973;Donelanetal.,1985 ;Ban ner ,1990 ;Wenetal.,1999) .Ondimensionalground ,Phillips (195 8)suggestedthattheequilibriumfre quencyspectrumofwindwavesfordeepwatershouldbe proportionaltoω- 5,andthecorrespondingwavenumberspectrumshouldbe proportionaltok- 4,whereωistheangularfrequencyandkisthewavenumber.Forfully developedwindwaves…     

Directional Spectrum of Wind Waves: Part Ⅱ- Comparison and Confirmation

1　Introduction1.1　Proposed ModelonDirectionalFrequencySpec trum　ThisisthePartⅡofthetwo papersetondirection alspectraofwindwaves.Anewmodelonthedirec tionalspectrumofwindwavesfordeepwaterispro posedbasedonthestatisticsofwindwavesinthePartⅠ .Substituting (4 5 )ofPartⅠinto (4 0 )andaddingapeak enhancementitemγΓ,weobtainS(ω ,) =0 .0 0 93αaαwD( ,k) ωpω2 ξ- 4g2ω5×exp - 2 ξ+14[bωp +(1-b)ωp]4ω4 γΓ. (1)Here ,αaisthewaveagefactorofspectralcoefficientdefinedbyαa = ω0 .55…     

DEM FROM SAR:PRINCIPLE AND APPLICATION

1　IntroductionWiththetechnologicalimprovementsofradarimagerysystems,thescientificcommunitieshavebetteropportunitiestostudyapplicationsinvariousremotesensingfieldssuchasoceanography ,geolo gy ,atmosphere ,cartography ,environmentsurveil lance .Theseresearchstudieshaveacommonobjec tive:toknowmoreabouttheearth’senvironmentandtheinaccessiblecelestialobjectsmoreprecisely .Cartographicinformationisimportantformanyfields:theterritorydevelopmentanddefense ,theforestforecasts,theminingresources,etc.F…     

PRIMARY STUDY OF SULFATE AND CARBONACEOUS AEROSOLS IN BEIJING

Results of our aerosol study, performed during 1983–1984 in Beijing, demonstrate that ambient carbonaceous aerosols are derived mainly from coal combustion. Different SO₂ oxidation processes have been observed in summer and winter. The winter sulfate appears to be produced locally and associated with products of incomplete combustion.     

有关土壤系统内部临界阈的几个例子

一、石灰性母质中的粘粒移动碳酸盐淋溶是土壤粘粒以淋溶方式迁移的一个必要条件（搏尔等,1980）。像Ca⁺⁺和Mg⁺⁺等二价阳离子具有强烈的凝聚作用,可抑制粘粒的淋溶。在湿润环境中,碳酸盐最终要被淋洗掉,当活性碳酸盐和交换性Ca⁺⁺淋洗到一定程度时,粘粒就不再以凝聚状态存在而开始移动,此时,碳酸盐和Ca⁺⁺的含量即可看作一种临界阈值。     

印度马德拉斯含水层系统水文地球化学对人类健康的影响

从1985年开始,安娜大学水资源中心在马德拉斯含水层系统(MAS)有规律地进行了水文地球化学研究,该含水层系统包括北-西北部多层含水层和南部半承压含水层。马德拉斯大城市居民的60～70~*％,供水来自马德拉斯含水层系统,在干旱年份,近     

由计算机产生建造地貌立体模型之模片

本文叙述两种用于绘制建造三维地貌立体模型所需模片的制图算法。从美国国防制图局的1:250000比例尺数字地形磁带中提取高程数据,用来组装等高线立体模型和剖面立体模型。     

DRY-WET EVOLUTION IN GUANGDONG PROVINCE DURING LAST 500 YEARS

1 INTRODUCTIONThe global warming change has already become one ofthe focuses that many scientists pay attention to, and theprecipitation change of China is also one part of thequestionsunder the whole world changes today. Accord-ing to the actual material analysis, the climate in Chinahad a warm-dry tendency in a wide spread range duringthe past one hundred years (ZHAO, 1993), and it couldnot draw a verdict as for future tendency at present. Fol-lowing the thought of Prof. HUANG Bing…     

The Latest Research Progress on El Ninod

1　ＭａｔｈｅｍａｔｉｃＭｏｄｅｌｏｆＴｉｄａｌＶｉｂｒａｔｉｏｎＳｕｐｐｏｓｅｔｈａｔ 3ｓｅｍｉ -ａｘｅｓｏｆａｅｌｌｉｐｓｏｉｄａｒｅａ ,ｂａｎｄｃ (ａ >ｂ >ｃ) ,ｌａｔｉｔｕｄｅｉｓθ ,ｌｏｎｇｉｔｕｄｅｉｓψ(ｃｈａｎｇｉｎｇｆｒｏｍ 0°ｔｏ 90°) ,