黄河改道与地图断代:中国地图学西传辩证     

李兆良 《测绘科学》2017,42(4)

黄河经常改道,给中国带来肥沃的耕地,也带来灾难。历代黄河河道变迁反映在地图上,可以断定地图的成图年代。先秦至宋代,黄河基本在华北平原用不同河道进入渤海。自1194年开始,黄河夺淮,分两支,北入渤海,南注黄海。1580年治河后,黄河只有南支汇淮河入黄海,到1855年再恢复单支入渤海。黄河4次大改道的历史可以印证地图成图年代。《坤輿万国全图》上的黄河分两支,为1194—1580年状态,不是利玛窦与李之藻时代的黄河,他们应该目击而未更正,证明两者均没有参加《坤輿万国全图》的测绘,地图存在远较二人时代为早。卫匡国的《中国新地图集》,黄河只表示南支入黄海,是1580年以后的材料,比1541年的《广舆图》资料更新。地图制作有勘探、测绘、拼合、制版、印刷、翻译等步骤。严格来说,地图最重要的创作者是勘探测绘者,其他的任务是后勤,翻译重绘更是省事。《中国新地图集》主要制作人不是卫匡国,实为中国历代省、县、乡分工测绘,明代统其成,已用经纬线,球形投影绘制。《坤輿万国全图》则是郑和等率领大航海的经验总结。卫、利、李等人只参与翻译,添加地名和序言。这两份外国保存的中国地图重现中国历史,证明郑和时代的大航海是世界地理大发现的先驱,近代地图学为中国原创,中国地图学西传才更接近史实。  相似文献   

Tidal influence on the sea-to-air transfer of CH₄ in the coastal ocean     

DOSHIK HAHM  GUEBUEM KIM  YONG-WOO LEE  SUNGH-YUN NAM  KYUNG-RYUL KIM  KUH KIM 《Tellus. Series B, Chemical and physical meteorology》2006,58(1):88-94

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应用E-ε湍流动能闭合湖泊热力学过程模型对东太湖湖-气交换的模拟     

程昕  王咏薇  胡诚  王伟  张弥  肖启涛  刘寿东  李旭辉 《Acta Meteorologica Sinica》2016,74(4):633-645

采用考虑沉水植物影响的E-ε湍流动能闭合湖泊热力学过程模型,模拟2013年8月东太湖湖-气交换过程,并利用太湖的站点观测数据对模型进行了验证。太湖水温的模拟值与观测值吻合较好,模型计算的各层水温与观测值相比,均方根误差均未超过1℃。同时模型也较好地模拟出太湖表面感热通量和潜热通量,潜热通量的模拟值与观测值的标准差为54.7 W/m²。由于湖水较浅,太湖的水温层结会明显受到天气状况的影响。晴朗小风条件下的湖水呈现显著的热分层现象,当风速为0.8 m/s,高层和底层的温差达到7.9℃。大风天气条件驱动较强的水体湍流混合,水温的热分层消失,风速为12 m/s,湖泊上层与底层的水温差仅0.12℃。此外,模拟结果较好地呈现出了东太湖沉水植物的存在通过增大湖体消光系数,减小到达湖体内部的热量,并增加对湖水的阻力,影响湖体中湍流动能的分布,并进而影响湖水温度的分布。综上所述,该模型能够较好地模拟出浅水大湖湖-气交换的过程。  相似文献   

Horizontal distribution of Changjiang Diluted Water in summer inferred from total suspended sediment in the Yellow Sea and East China Sea     

LEE Dong-Kyu  KWON Jae-Il  SON SeungHyun 《海洋学报(英文版)》2015,34(12):44-50

During the summer in the Yellow Sea and East China Sea, the resuspension of the bottom sediment is obstructed by strong stratification and, as a result, the concentration of total suspended sediment (TSS) can be used as an excellent tracer for Changjiang Diluted Water (CDW). To analyze the spatial and temporal variations of the CDW distribution, the monthly mean TSS from Moderate Resolution Imaging Spectroradiometer (MODIS) ocean color data are constructed and are converted to salinity using the relationship between salinity observed from AQUARIUS and TSS. The process produces the detailed horizontal distribution of salinity with very high resolution (1 km). From monthly mean salinity map from 2002 to 2012 in July and August, the expansion patterns of CDW are analyzed. The southerly wind in July and southeasterly wind in August transport the CDW eastward and northeastward, respectively. It is found that the yearly variation of the expansion of CDW toward the southern sea area of Korea is mostly due to the variation of southerly wind and the fluctuations of fresh water discharge into the Changjiang estuary show relatively little impact on the eastward extend of CDW. When 11-year mean (from 2002 to 2012) salinity map in August is compared with World Ocean Atlas 2013, it is revealed that wind in August strengthened six times from 1994 and it causes the expansion of CDW extended 150 km further eastward.  相似文献   

Multivariate analysis of .uorescence and source identi. cation of dissolved organic matter in Jiaozhou Bay, China     

JIANG Fenghu  YANG Baijuan  LEE Frank Sen-Chun.  WANG Xiaoru  CAO Xuan 《海洋学报(英文版)》2009,(2):60-72

Hierarchical clustering analysis and principal component analysis (PCA) methods were used to assess the similarities and dissimilarities of the entire Excitation-emission matrix spectroscopy (EEMs) data sets of samples collected from Jiaozhou Bay, China. The results demonstrate that multivariate analysis facilitates the complex data treatment and spectral sorting processes, and also enhances the probability to reveal otherwise hidden information concerning the chemical characteristics of the dissolved organic matter (DOM). The distribution of di.erent water samples as revealed by multivariate results has been used to track the movement of DOM material in the study area, and the interpretation is supported by the results obtained from the numerical simulation model of substance tracing technique, which show that the substance discharged by Haibo River can be distributed in Jiaozhou Bay.  相似文献   

A preliminary study of the variation of phytoplankton absorption coefficients in the northern South China Sea     

WUJingyu  HONGHuasheng  SHANGShaoling  DAIMinhan  LEEZhongping  LIShaojing 《海洋学报(英文版)》2009,28(5):17-29

The temporal and spatial variabilities of phytoplankton absorption coefficients (a ph (λ)) and their relationships with physical processes in the northern South China Sea were examined, based on in situ data collected from two cruise surveys during May 14 to 25, 2001 and November 2 to 21, 2002. Significant changes in the surface water in a ph values and B/R ratios (a ph (440)/a ph (675)) were observed in May, which were caused by a phytoplankton bloom on the inner shelf stimulated by a large river plume due...  相似文献   

Identifying Indicator Species in Habitats Created by Coastal Structures   总被引：1，自引：1，他引：0  

Chun-Han SHIH  Ying-Chou LEE  Wei-Tse CHANG  Ta-Jen CHU 《中国海洋工程》2010,24(1):117-134

In this paper,three approachs were developed to find indicator species from the habitat created by coastal structures.These approachs consist of a model of species co-occurrence probability,a model of k-environmental factor probability and a composite model.Simultaneously,a case study was conducted in Hsinchu Fishing Port of north-western Taiwan.Based on the aforementioned models,three primary producer species,Ahnfeltiopsis flabelliformis,Chondrus ocellatus and Sarcodia montagneana,were chosen as the indicator species which had the highest co-occurrence probabilities and showed greater tolerance to more critical environment.It is imperative to understand how the three species under particular co-occurring conditions and environmental factors influence the composition of sessile assemblages in coastal water.The results indicate that for the purpose of increasing biodiversity,these models are feasible to find indicator species of artificial structures,and to help make it possible to design coastal structures based on biological considerations.This study provides an innovative approach for further advanced application in the artificial habitat of coast management.  相似文献   

四层模式热成风适应   总被引：1，自引：1，他引：1  

陈秋士  励名德 《气象学报》1964,34(3):253-270

本文用四层模式分析了热成风适应。在适应过程中将发生四种波速不同的惯性波来调节流场和温度场的关系。它们的前阵面的速度分别为306米/秒,114米/秒,36.2米/秒,19.2米/秒。层次愈高,快速惯性波的作用愈大;惯性外波在750毫巴以下才有它的重要性。 计算指出:大气中辐合辐散以及垂直运动在垂直方向上互相迭置的现象,是一定条件下热成风适应的结果。本文计算了各种情况的初始条件下温度场和气压场的相互调整。例如375毫巴上单纯非地转风的流场的反气旋涡旋,适应后可建立起对流层暖性、平流层是冷性的高压系统。将初始非热成风的暖温度中心,放在对流层下层和放在对流层中层适应后的结果将不一样。前者只能在对流层下层形成一浅薄的热低压,而后者可在对流层上层建立起一个强大的反气旋,甚至一直影响到平流层。最后,结合气旋发展时所产生的非热成风的特点,讨论了它们的适应。  相似文献   

DIRECT INTERPRETATION OF RESISTIVITY DATA OVER TWO-DIMENSIONAL STRUCTURES*     

T. LEE 《Geophysical Prospecting》1981,29(3):462-469

A direct interpretation scheme is developed which is capable of determining most of the geological features of a ground which can be assumed to be two dimensional in structure. This scheme extends the earlier work of Pekeris (1940) and Koefoed (1968) to the case where the basal layer of a ground is undulating. It also has a limited use for finding the parameters of a dipping dyke in the lower medium. Though the top and dip of the dyke can be determined, this is not true for the thickness.  相似文献   

台湾崩塌地的分类与防治工法   总被引：1，自引：1，他引：1  

李锦育 《山地学报》2001,19(5):425-429

台湾本岛南北轴长约385km，东西最这处约143km，中央山脉纵贯本岛南北长约350km，其中至少有25个以上的主峰海拔高度超过3000m，台湾山地面积约占总面积70％，不但地质环境复杂，地势陡峻，土壤浅薄、河流短急，降雨多、强度大且集中，山坡地崩塌常随着台风、豪雨及地震、或伴随着人为的破坏还引起，屡屡造成重大灾害。崩塌常发生于特定地质或地质结构上，尤以坡地或台地的缓坡面为最多，其移动缓慢而有特续性及周期（反复）性。本研究针对台湾坡地崩塌的特性试作型态上的分类，并寻求其有效且可行之防治工法，盼能降低灾害所造成之损失，并确保该区域人民之生命及财产之安全。  相似文献