义乌市降水变化特征分析          下载免费PDF全文

冯利华  赵贤产  毛樟林  华云峰  朱跃娟  朱持则  张行才  骆高远 《气象与环境学报》2008,24(1):1-4

根据历史和实测资料的统计分析,得到义乌市的降水变化特征。结果表明:丰水期义乌市的涝年偏多,旱年偏少,而枯水期则旱年偏多,涝年偏少。厄尔尼诺事件的当年或翌年,义乌市的降水显著偏多,而拉尼娜事件的当年或翌年,义乌市的降水则显著偏少。丰水期平均入梅日偏早,平均出梅日偏晚,平均梅雨日数偏长,平均梅雨量偏多,而在枯水期则反之。义乌市6月6—15日入梅的可能性最大,出梅日期的时间分布相对比较分散,其集中期的发生规律不如入梅集中期明显。厄尔尼诺事件的当年或翌年,义乌市的出梅日偏晚,而拉尼娜事件的当年或翌年,义乌市的出梅日偏早。研究结果可为水库源区雨季的人工增雨作业提供科学依据。  相似文献   

地磁扰动事件的描述及处理   总被引：1，自引：1，他引：0  

陈健  刘江斌  张秀霞  李松华 《地震地磁观测与研究》2008,29(6):45-49

影响地磁观测的因素很多,只有充分了解干扰的机制,才能对其数据进一步的处理。而在GM3,GM4提供秒采样数据后,观测数据中干扰数据的形态就可以非常清晰。本文就是利用秒采样的数据对几种常见干扰情况进行了描述,并使用软件对干扰数据进行剔除。  相似文献   

全球变暖减速与郭增建的“海震调温假说”   总被引：2，自引：0，他引：2       下载免费PDF全文

杨冬红  杨学祥 《地球物理学进展》2008,23(6):1813-1818

数值计算表明,潮汐形变和潮汐震荡是海流循环和季节性厄尔尼诺现象发生的原因.2004年12月26日印尼地震海啸后,全球低温冻害和暴雪灾害频繁发生.气候潮汐循环说和"深海巨震降温说"是一种合理的解释,2005～2008年全球气温因为强潮汐和地震海啸而降低.西方科学家也承认了这一客观事实:过去两年里,自然气候的变化抵消了全球气候变暖效应并将继续促使气温在2008年保持缓慢变化的趋势.气候潮汐循环说和海震调温说,阐明了冷气候、强潮汐和强震相互对应的物理机制,对2000年地球进入拉马德雷冷位相后的气候预测有重大科学意义.中国连续18年暖冬的终结是2000年地球进入拉马德雷冷位相和印尼发生地震海啸的合理结果.规律表明,在拉马德雷冷位相时期,全球强震、低温、飓风伴随拉尼那、全球性流感伴随厄尔尼诺将越来越强烈.地球自转、最强潮汐和特大地震都有准四年周期.特大地震可能发生在2000～2030年拉马德雷冷位相时期中的前18年左右.  相似文献   

各向同性介质长偏移距地震同相轴动校正   总被引：3，自引：2，他引：1       下载免费PDF全文

尤建军  陈强  张超谟  常旭 《地球物理学进展》2008,23(4):1173-1178

传统二阶动校正方法基于较小最大偏移距与目标层深度比和地震波沿直线传播假设,进行长偏移距地震资料处理时,这些假设不再成立.高阶项动校正公式能提高长偏移动校正精度,文中对几种典型的高阶项动校正方法进行了比较,并提出了优化四阶、优化六阶动校正方法.模型计算表明,高阶项动校正方法能取得较常规动校正方法好的动校正结果,但并非阶数越高动校正精度就越高;在纵向速度变化剧烈时,高阶动校正或优化高阶动校正方法一般不能适用于最大偏移距与目标层深度大于3.5的地震反射同相轴,优化四阶和优化六阶动校正公式由于考虑了无穷大偏移距的影响,具有更稳定、更加精确动校正效果,适合于实际的各向同性长偏移距地震资料处理.  相似文献   

Links between global CO<Subscript>2</Subscript> variability and climate anomalies of biomes     

Tao Zhou  ChuiXiang Yi  Peter S. Bakwin  Li Zhu 《中国科学D辑(英文版)》2008,51(5):740-747

The global rate of fossil fuel combustion continues to rise, but the amount of CO₂ accumulating in the atmosphere has not increased accordingly. The causes for this discrepancy are widely debated. Particularly, the location and drivers for the interannual variability of atmospheric CO₂ are highly uncertain. Here we examine links between global atmospheric CO₂ growth rate (CGR) and the climate anomalies of biomes based on (1986–1995) global climate data of ten years and accompanying satellite data sets. Our results show that four biomes, the tropical rainforest, tropical savanna, C₄ grassland and boreal forest, and their responses to climate anomalies, are the major climate-sensitive CO₂ sinks/sources that control the CGR. The nature and magnitude by which these biomes respond to climate anomalies are generally not the same. However, one common influence did emerge from our analysis; the extremely high CGR observed for the one extreme El Niño year was caused by the response of the tropical biomes (rainforest, savanna and C₄ grassland) to temperature.  相似文献   

Chronology and geochemistry of the volcanic rocks in Woruo Mountain region,northern Qiangtang depression: Implications to the Late Triassic volcanic-sedimentary events   总被引：3，自引：0，他引：3  

Wang Jian  Fu XiuGen  Chen WenXi  Wang ZhengJiang  Tan FuWen  Chen Ming  Zhuo JieWen 《中国科学D辑(英文版)》2008,51(2):194-205

A suite of sedimentary-volcaniclastic rocks intercalated with the volcanic rocks unconformably overlies the Triassic Xiaochaka Formation in the Woruo Mountain region, Qiangtang Basin, northern Tibet. The vitric tuff from the base of these strata gives a SHRIMP zircon U-Pb age of 216 ± 4.5 Ma, which represents the age of the Late Triassic volcanic-sedimentary events in the Woruo Mountain region, and is consistent with that of the formation of the volcanic rocks from the Nadi Kangri Formation in the Nadigangri-Shishui River zone. There is a striking similarity in geochemical signatures of the volcanic rocks from the Woruo Mountain region and its adjacent Nadigangri-Shishui River zone, indicating that all the volcanic rocks from the Qiangtang region might have the same magmatic source and similar tectonic setting during the Late Triassic. The proper recognition of the Late Triassic large-scale volcanic eruption and volcanic-sedimentary events has important implications for the interpretation of the Late Triassic biotic extinction, climatic changes and regressive events in the eastern Tethyan domain, as well as the understanding of the initiation and nature, and sedimentary features of the Qiangtang Basin during the Late Triassic-Jurassic.  相似文献   

1986～1987年El Niño期间热带西太平洋及南海海气热量交换研究   总被引：2，自引：0，他引：2  

吴迪生  邓文珍  詹进源  林晓能  王祖渊 《气象学报》1999,57(1):121-128

文中根据热带西太平洋海气相互作用研究（ＴＯＧＡ）第１～５及第８航次和南海科学考察结果,对热带西太平洋和南海海气热量交换作了分析。结果表明：ＥｌＮｉｎｏ事件发生前,热带西太平洋及南海海气热量交换非常强烈;ＥｌＮｉｎｏ事件发生后,热带西太平洋及南海海气热量交换反而减弱。  相似文献   

An improved age framework for late Quaternary silicic eruptions in northern Central America   总被引：1，自引：0，他引：1  

William I. Rose  F. Michael Conway  Carlos R. Pullinger  Alan Deino  William C. McIntosh 《Bulletin of Volcanology》1999,61(1-2):106-120

 Five new stepwise-heating ⁴⁰Ar/³⁹Ar ages and one new high-sensitivity ¹⁴C date of ash-fall and ash-flow deposits from late Quaternary silicic volcanoes in northern Central America document the eruption rates and frequencies of five major rhyodacite and rhyolite calderas (Atitlán, Amatitlán, Ayarza, Coatepeque, and Ilopango) located north of the basalt, andesite, and dacite stratovolcanoes of the Central American volcanic front. These deposits form extensive time-stratigraphic horizons that intercalate regionally, and knowledge of dates and stratigraphy provides a valuable framework for age determinations of more localized volcanic and nonvolcanic events. The new data, especially when integrated with previous stratigraphic and dating work, show that all five calderas erupted several times in the past 200 ka and, despite a lack of historic activity, should be considered as active centers that could produce highly explosive eruptions again. Because of their locations near the highly vulnerable economic hearts of Guatemala and El Salvador, the risks of eruptions from these calderas should be carefully considered along with risks of major earthquakes and volcanic front volcanoes, which are much more frequent but inflict less severe and extensive damage. This investigation also includes some examples of dating efforts that failed to produce reasonable results. Received: 15 May 1998 / Accepted: 18 January 1999  相似文献   

新疆乌恰7.4级地震前蛟河井水位异常特征——吉6井远震效应再研究   总被引：1，自引：0，他引：1  

李富 《东北地震研究》1999,15(4):37-41

1985年8月23日,新疆乌恰发生了Ms7.4级地震,临震前,吉林省蛟河井水位出现十种异常,对其形态、幅度、持续时间等特点进行了分析研究,提出了水位固体潮系数、降雨与水位之间的比值可做为判别地震前异常的指标,扼要地阐述了诸异常的关系,对远震效应机制进行了讨论。  相似文献   

据赤道经向风剖面及岛屿站风资料诊断厄尔尼诺事件     

厉善华  林传兰 《海洋学研究》1998,16(3):1-6

据赤道经向风剖面及热带西太平洋岛屿站测风资料来诊断厄尔尼诺（ＥｌＮｉｎｏ）事件,试图从观测事实方面来跟踪与预测ＥｌＮｉｎｏ的发生。分析结果得出：气候监测公报中８５０ｈＰａ风指数对监测、诊断已发生的ＥｌＮｉｎｏ事件较好,但不能用来预测ＥｌＮｉｎｏ事件的发生,而热带西太平洋岛屿站月平均纬向风对ＥｌＮｉｎｏ事件的发生有一定的指示意义。从越赤道气流的演变特征进一步证明,ＥｌＮｉｎｏ事件对应于弱季风,而拉尼娜（ＬａＮｉｎａ）事件对应于强季风。  相似文献