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1.
Based on Total Ozone Mapping Spectrometer (TOMS) monthly aerosol optical thickness (AOT) measurements in 1980–2001 a study is made of space/time patterns and difference between land and sea of AOT 0.50 μm thick over China,which are put into correlation analysis with synchronous extreme temperature indices (warm/cold day and night).Results suggest that 1) the long-term mean AOT over China is characterized by typical geography,with pronounced land-sea contrast.And AOT has significant seasonality and its seaso...  相似文献   

2.
On the basis of the temperature observations during 1961-2000 in China, seven coupled general circulation models' (GCMs) extreme temperature products are evaluated supplied by the Intergovernmental Panel on Climate Change' s 4th Assessment Report (IPCC-AR4). The extreme temperature indices in use are frost days (FD), growing season length (GSL), extreme temperature range (ETR), warm nights (TN90), and heat wave duration index (HWDI). Results indicate that all the seven models are capable of simulating spatial and temporal variations in temperature characteristics, and their ensemble acts more reliable than any single one. Among the seven models, GFDL-CM2.0 and MIROC3.2 performances are much better. Besides, most of the models are able to present linear trends of the same positive/negative signs as the observations but for weaker intensities. The simulation effects are different on a nationwide basis, with 110°N as the division, east (west) of which the effects are better (worse) and the poorer over the Qinghai-Tibetan Plateau in China. The predictions for the 21st century on emissions scenarios show that except decreases in the FD and ETR, other indices display significant increasing trend, especially for the indices of HWDI and TN90, which represent the notable extreme climate. This indicates that the temperature-related climate is moving towards the extreme. In the late 21st century, the GSL and TN90 (HWDI) increase most notably in southwest China (the Qinghai-Tibetan Plateau), and the FD decrease most remarkably in the Qinghai-Tibetan Plateau, northwest and northeast of China. Apart from South China, the yearly change range of the extreme temperature is reduced in most of China.  相似文献   

3.
Distributions and sources of total organic carbon (TOC)in seabed sediments and their implications for hydrodynamics are analyzed, in the turbidity maximum of the Changjiang Estuary. Ecology ecoenvironmental effects of estuary water on the continuously increasing terrigenous organic carbon from the Changjiang River are also explored through variations of organic carbon content and water quality indicators. Results show that, hydrodynamics exert important influences on distributions of organic carbon in the tur- bidity maximum of Changjiang Estuary. For their redistribution effect of terrigenous organic carbon within the moving layer in the whole region, variations from land to sea are not indicated by surficial and vertical average values of TOC and total nitrogen (TN) contents in core sediment, as well as organic stable carbon isotopes in surface sediments. However, on the long-time scale, the trend of terrigenous organic carbon decreasing from land to sea is still displayed by variations of stable carbon isotopic average values becoming heavier from land to sea. Previous studies have shown that high content of Chl a cannot appear in the Changjiang Estuary in despite of adequate nourishment supply, because photosynthesis of phytoplankton is constrained by high suspended sediment concentration(SSC). However, an area with a high content of Chl a occurs, which may be caused by resuspended benthic algae with bottom fine grain-size sediments. Tremendous pressures are imposed on the environment of Changjiang Estuary, because of uhrophication trends and special hydrodynamics. Phytoplankton bloom area tends to extend from the outer sea to the mouth of Changjiang River.  相似文献   

4.
On the basis of the analysis of the sea temperature data that are observed from the three automatic temperature line acquisition sysem mooring buoys deployed in the central South China Sea (SCS) during South China Sea monsoon experiment, vertical features of biweekly and synoptic variability are discussed. There are five vertical modes, that is, subsurface temperature variability is in phase with,out of phase with, leads to, lags the surface temperature variability, and at depths within the subsurface layer the upper and lower temperature variations are out of phase. The formation of these vertical modes is related to the property of low-level atmospheric forcing and to the background in atmosphere and ocean. Wind stress curl is the main driving factor in forming Modes 1 and 3, and wind stresses in forming Modes 2 and 4.  相似文献   

5.
The global surface temperature change since the mid-19th century has caused general concern and intensive study. However, long-term changes in the marginal seas, including the seas east of China, are not well understood because long-term observations are sparse and, even when they exist, they are over limited areas. Preliminary results on the long-term variability of sea surface temperature (SST) in summer and winter in the seas east of China during the period of 1957-2001 are reported using the Ocean Science Database of Institute of Oceanology, Chinese Academy of Sciences, the coastal hydrological station in situ and satellite data. The results show well-defined warming trends in the study area. However warming and cooling trends vary from decade to decade, with steady and rapid warming trends after the 1980s and complicated spatial patterns. The distribution of SST variation is intricate and more blurred in the areas far away from the Kuroshio system. Both historical and satellite data sets show significant warming trends after 1985. The warming trends are larger and spread to wider areas in winter than in summer, which means decrease in the seasonal cycle of SST probably linked with recently observed increase of the tropical zooplankton species in the region. Spatial structures of the SST trends are roughly consistent with the circulation pattern especially in winter when the meridional SST gradients are larger, suggesting that a horizontal advection may play an important role in the long-term SST variability in winter.  相似文献   

6.
20世纪90年代后期南海上层海温变化趋势的转折   总被引:1,自引:1,他引:0  
In this paper, the interdecadal variability of upper-ocean temperature in the South China Sea(SCS) is investigated based on several objectively analyzed data sets and two reanalysis data sets. The trends of the SCS sea surface temperature(SST) have changed from warming to cooling since the late 1990 s. A heat budget analysis suggests that the warming of the surface mixed layer during 1984–1999 is primarily attributed to the horizontal heat advection and the decrease of upward long wave radiation, with the net surface heat flux playing a damping role due to the increase of upward latent and sensible heat fluxes. On the other hand, the cooling of the surface mixed layer during 2000–2009 is broadly controlled by net surface heat flux, with the radiation flux playing the dominant role. A possible mechanism is explored that the variation of a sea level pressure(SLP) over the North Pacific Ocean may change the prevailing winds over the SCS, which contributes to the change of the SST in the SCS through the horizontal heat advection and heat fluxes.  相似文献   

7.
Possible impact of reduced Arctic sea-ice on winter severe weather in China is investigated regarding the snowstorm over southern China in January 2008. The sea-ice conditions in the summer (July-September) and fall (September-November) of 2007 show that the sea-ice is the lowest that year. During the summer and fall of 2007, sea ice displayed a significant decrease in the East Siberian, the northern Chukchi Sea, the western Beaufort Sea, the Barents Sea, and the Kara Sea. A ECHAM5.4 atmospheric general circula- tion model is forced with realistic sea-ice conditions and strong thermal responses with warmer surface air temperature and higher-than-normal heat flux associated with the sea-ice anomalies are found. The model shows remote atmospheric responses over East Asia in January 2008, which result in severe snowstorm over southern China. Strong water-vapor transported from the Bay of Bengal and from the Pacific Ocean related to Arctic sea-ice anomalies in the fall (instead of summer) of 2007 is considered as one of the main causes of the snowstorm formation.  相似文献   

8.
By using a method of boundary temperature index of seasons, a classification of hydrological climatic seasons in the China seas is made on the basis statistics of the sea surface air and water temperatures over the years. The results indicate that the assignment of hydrological seasons in the China seas differs with various sea areas. It may be divided into three climatic belts. In the temperate zone area, four seasons are clearly distinct with very long winter. While in the subtropical zone area, there is no winter throughout the year. The autumn is linked together with the spring, and the summer is unusually long. As for the tropical zone area, it is summer all the year round without any other seasons. In addition , the regular pattern of transformation of the four seasons and the regional characteristics of the length of each season are analyzed in greater detail. The results are in agreement with the continental seasonal classification and it is also shown that the results are reasonable and reliabl  相似文献   

9.
A large area hypoxia has been already reported respectively by two interdisciplinary surveys off the Changjiang Estuary since summer of 1999 and 2006. The hypoxic zone shows distinct year-to-year variations. Observed oceanographic data are first analysized and reveal a big difference for the Changjiang Diluted Water (CDW) between these two periods. These great changes are related to the tremendous reduction of the freshwater discharge and variations of wind fields between these two years. It is also found that the monthly mean intrusion of Kuroshio and its branches has increased in the northern East China Sea (ECS), but decreased in the southern ECS in August of 2006 as compared with 1999 on the base of general circulation models. Then, the Regional Ocean Modelling Systems is applied to the East China Sea to evaluate the contributions and relative importance of impacts from the river discharge, wind forcing and open boundary data. Our simulations reproduce the phenomena that more fresh water extends northeastward in 2006 and forms a negative SSS anomaly to the northeast of the river mouth as compared with 1999, which is consistent with observations. The five group numerical tests suggest that the wind forcing dominates the CDW variations followed by the Kuroshio and its branches. The study implies important roles played by hydrodynamic processes on the variability of hypoxic zone in the study areas.  相似文献   

10.
The sea surface temperature (SST) of the East China Sea (ECS) increased in the past decades,which may have a great impact on the ecosystem of the ECS,including the changes in plankton-population structure.In this paper,the changes in peaked abundance of Calanus sinicus in the Changjiang River (Yangtze River) Estuary were compared between 1959 and 2002,based on the data collected from the seasonally oceanographic cruises and those performed in spring of 2005.It was much higher in spring compared with that in other seasons both in 1959 and 2002.Furthermore,in spring 2005,the time for occurrence and decrease of the peaked C.sinicus abundance advanced about one month, accompanying the increase in the sea surface water temperature (SST).It peaked in June and decreased in July in 1959,however,in 2005,it peaked in May and attenuated sharply in early June.The earlier decrease of peaked C.sinicus abundance may further deteriorate the ecosystem in the Changjiang River Estuary and north nearshore of the ECS.  相似文献   

11.
通过与地基气溶胶观测数据的对比,确认了SeaWiFS气溶胶光学厚度产品用于研究中国海域气溶胶分布和变化特征的有效性。在此基础上,分析了中国海域气溶胶光学厚度的季节变化和地理分布特征。研究结果表明,中国东部海域平均气溶胶光学厚度存在以中纬度为中心的纬向分布;受沙尘、季风气候的影响,中国海域气溶胶光学厚度存在季节变化,不同海区有不同的季节变化和分布特征。渤海、黄海及东海有类似的变化特征,春季都受到沙尘气溶胶的影响,使中国东部海域气溶胶光学厚度普遍高于0.160,且对东海的影响最大;夏、秋季逐渐减小,冬季有所回升。南海气溶胶光学厚度均值为0.150,随时间变化不明显,但地理分布变化显著;受季风气候的影响,从春季到冬季,气溶胶光学厚度高值中心从高纬海域向低纬海域转移,范围也逐渐扩大。冬季南海大部分海域气溶胶光学厚度都达到0.160以上,是整个中国海域冬季气溶胶光学厚度最大的海区。气溶胶光学厚度的季节变化和地理分布特征为研究中国海区域气候变化和海洋生态提供了依据。  相似文献   

12.
中国近海海表温度变化的极端特性及其气候特征研究   总被引:4,自引:0,他引:4  
本文基于1982–2017年日再分析数据,分析了中国近海海表温度变化的极端特性、历史演变、空间格局及可能影响,并探讨了与全球变化和区域气候变率的关联性。近30多年来,中国近海海表总体升温明显,尤以春季长江口附近及以南的外部近岸海域升温最为显著,线性升温速率高达0.2°C/(10 a)。相比而言,沿岸海域对气候变暖暂缓的响应可能更为明显;极端高(低)温强度以显著增强(减弱)为主,尤以春(夏)季幅度最大。沿岸海域春季极值温差增强显著,易通过物候变化引起生物迁移和赤潮等生态灾害突发、频发;北部海域极端事件持续天数大于南部,其中,黄海、东海极端高温持续天数增加显著,可能对渔业资源产生较大影响。受气候变暖暂缓影响,极端低温持续天数亦显著增加;极端高温在长江口附近,台湾海峡和南海北部等海域累积频次上升显著,未来极端海洋热浪事件可能持续增加,将对南海珊瑚礁等产生较大影响。极端低温累积频次以显著降低为主。然而长江口及以南沿岸极端低温在冬春季增强明显,可能对红树林等产生一定影响;太平洋年代际振荡(PDO)暖位相期间,ENSO暖事件得到增强,易引起中国近海海表极端低温的频发。北极涛动(AO)正位相时,限制了极区冷空气向南扩展,中国近海海表极端高温频次趋于增加,其危险性增强。  相似文献   

13.
卢峰  郑彬 《海洋学报》2011,33(5):39-46
利用1967-2009年的逐月海表温度(Sea Surface Temperature,SST)资料和降水资料,以及经验正交函数(Empirical Orthogonal Function,EOF)和相关分析方法,探讨了亚印太交汇区(Joining Area of Asia and Indian-Pacific Oce...  相似文献   

14.
2004年秋季冷空气活动对南海海表温度的影响   总被引:3,自引:2,他引:1  
利用航次观测和网上的有关资料对南海2次强度不同的冷空气活动及其对南海SST的影响进行了分析.结果显示,9月22日弱冷空气过程南下速度慢,在陆地上变性较明显,未造成南海SST的明显变化;而10月2日前后的强冷空气过程南下速度快,陆地上变性比较弱,造成南海SST明显下降.通过对南海海表热收支分析,发现南海北部SST下降主要是冷空气造成净热通量急剧增加,海洋失去热量,而南部SST下降可能是南部海面气旋式风应力引起的下层冷水上涌.初步解释了2004年秋季冷空气活动对南海SST的影响.  相似文献   

15.
金啟华  王辉  姜华  何春  刘珊 《海洋学报》2012,34(1):64-70
利用SODA资料和ECCO资料计算得到的北太平洋副热带海洋环流强度,和国家气候中心整编的中国160站逐月降水资料,结合NCEP/NCAR再分析资料和Hadley中心海表面温度资料,分析了1970-2007年海洋环流强度异常同期的大尺度大气环流异常特征及对中国东部夏季降水的影响。结果表明:海洋环流强度变化与长江中下游地区降水存在密切的反相关。环流强度异常可以通过影响西太平洋副热带高压的南北位置异常进而影响长江中下游降水。海洋环流偏弱时,副高位置偏南,长江中下游地区受气旋性环流异常影响,来自副高西北侧的强西南水汽输送至此,在该地区形成强水汽辐合中心,同时伴随上升运动加强和对流的加强,进一步导致该地区降水偏多;当海洋环流偏强时,西太平洋副高位置偏北,长江中下游地区受反气旋性环流异常影响,伴随辐散下沉及水汽辐散,导致该地区降水偏少;海洋环流强度异常导致的中纬度海区海表面温度异常,可能是导致副高南北位置异常的主要原因。  相似文献   

16.
华南中生代岩相变化及海相地层时空分布   总被引:20,自引:3,他引:17  
在搜集大量资料的基础上,分析了华南中生代地层时代、岩性、岩相对比关系,重点综述了中生代海相地层的时空分布特征。受所处构造部位的控制,华南中生代岩相时空变化总体上可分为3个区:东区(闽西南-粤东-粤北-粤中)、中区(粤西-桂东)、西区(滇西-滇东南)。中区在早三叠世以后完全隆升成陆,仅局部有山间盆地碎屑沉积。海相地层集中于东西两区,但存在明显的东西差异:海侵时间在东区为早三叠世、晚三叠世-早侏罗世和早白垩世,西区为中三叠世和中侏罗世;海侵方向在东区来自东南,西区则为中特提斯滇缅海的-部分。晚三叠世-早侏罗世的粤东海盆发育厚达5000m的海相和海陆交互相沉积,可能向南延伸到台西南盆地和南沙群岛东部,但它与南海西部围区的同时代海盆并不直接相通。  相似文献   

17.
宋德众 《台湾海峡》1990,9(3):275-282
本文通过分析华南海岸带约25a的气候资料,揭示了该地区主要气象要素(气温、降水、风)的递变特征。  相似文献   

18.
通过谐波分析的方法,对东亚31个冬季(1980—2010年)的气温提取年际变化分量(周期小于8a部分)进行EOF分析。结果发现:在年际变化的时间尺度上,东亚冬季气温表现为高纬模态和低纬模态2个主要模态,它们一起可以解释总方差73%的变化。进一步分析表明,在年际变化尺度上,与气温变化的高纬模态相联系的大气环流表现为显著的北极涛动(AO)负位相分布,海平面气压场上西伯利亚高压和阿留申低压北移,对流层中层东亚大槽西移,高层西风急流向西北方向移动;副热带北太平洋和阿拉斯加湾的海表面温度(SST)变化呈偶极子振荡分布,这种准两年的周期振荡对这一模态的出现有一定的预示意义。而与气温变化的低纬模态相联系的大气环流表现为类AO正位相分布,与之相关的西伯利亚高压和阿留申低压南移,对流层中层东亚大槽东移,高层的西风急流则是向东南方向移动;赤道东太平洋的SST异常可能对这一模态的形成有一定的作用,而东亚近海的SST则更多是被动地改变。此外,海冰异常变化与东亚冬季气温变化的联系主要体现在:在前夏和前秋,东西伯利亚海-波弗特海海冰异常减少(增加)对应着随后东亚冬季气温变化的高纬模态(低纬模态),而冬季东亚气温变化的高纬模态(低纬模态)又与后期春季北极东半球的海冰异常增加(减少)具有较好的相关性,此外白令海和鄂霍次克海的海冰异常变化是伴随东亚冬季气温变化产生的。  相似文献   

19.
沙洲并陆与长江口北部岸线的演变   总被引:4,自引:0,他引:4  
凌申 《台湾海峡》2001,20(4):484-489
全新世以来,长江口北岸南通-扬州南部经历了“浅海-陆地”的成陆过程。4ka,B.P.前,本区为一漏斗形的浅水海湾,河口拦门沙极为发育.4ka.B.P。以来,沙洲并岸,河口陆地淤长,长江口北部岸线呈东南延伸之势。  相似文献   

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