潮汐和地震对全球气候变化的影响

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。"潮汐调温说"和"深海巨震降温说"是一种合理的解释。根据"潮汐调温说"和"深海巨震降温说"理论,2005年全球气温将因为印尼地震海啸和强潮汐南北震荡而降低。美国国家航空航天局(NASA)的科学家认为,一个较弱的厄尔尼诺现象和人类排放的温室气体将使2005年成为人类有记载以来最热的一年。事实上,2005年的温度低于1998年。现在,西方科学家也承认了2005—2007年自然气候的变化抵消了全球气候变暖效应这一客观事实。     

El Nino事件当年和次年夏季低纬环流特征的初步分析

分析1950年以来中等强度以上的ElNiño和LaNina当年和次年夏季(7月)低纬度风场和500hPa高度距平场,发现有不同的特征。其中中-西太平洋近赤道地区850、200hPa上风场异常变化十分明显,这种异常变化与南北半球大气相互作用有密切关系。在500hPa高度距平场上,北半球中、高和低纬地区表现出不同的正、负距平分布型式。上述特点对气候短期预测有一定参考意义。     

Continued post-bleaching decline and changed benthic community of a Kenyan coral reef

During the global coral bleaching event of 1997/1998 Kenyan reefs experienced between 50% and 90% coral mortality, with coral cover at Malindi being reduced from 35–45% (pre-bleaching) to 10–20%. Even before this event there was concern that these reefs were being impacted by increased sediment loads from the nearby Sabaki River. Here we report that since 1998 coral cover has declined yet further with, in 2004, means of 5.1% being recorded at North Reef (within the non-fished Malindi Marine National Park) and 2.3% on Leopard Reef (within the fished Marine Reserve). Prior to bleaching 55 coral genera were recorded from the area, currently we find only 23. Meanwhile algal cover, especially the calcareous green alga Halimeda, has increased, and on Leopard Reef is twice that on North Reef. Taken with the evidence of previous studies, these data suggest a combined impact of coral bleaching with sedimentation and fishing.     

淮北地区2010年4月异常低温气候特征及成因分析

利用1961—2010年NCEP/NCAR再分析资料和4月淮北地区气温资料,用累积距平(CA)法、合成分析法对淮北地区气温的时空分布特征以及2010年4月淮北地区持续冷气候背景进行分析。文章分析了淮北地区4月冷、暖年的大气环流异常及要素场的空间分布特征。结果表明:淮北地区4月气温的年代际变化特征明显,在1990年前后发生了突变。贝加尔湖南部,100°E以东的华北地区中低层的冷空气活动与淮北地区4月气温高低存在很好的相关性,该地中低层冷空气强(弱),淮北地区4月气温低(高)。冷暖年,乌拉尔山暖脊、东亚大槽、西伯利亚高压等差异显著,说明以上是影响淮北地区4月气温异常的关键系统。另据分析,El Nino与淮北地区4月气温异常也具有很好的相关性。     

Distinguished Effects of Interannual Salinity Variability on the Development of the Central-Pacific El Nino Events

El Nio events in the central equatorial Pacific (CP) are gaining increased attention,due to their increasing intensity within the global warming context.Various physical processes have been identified in the climate system that can be responsible for the modulation of El Nio,especially the effects of interannual salinity variability.In this work,a comprehensive data analysis is performed to illustrate the effects of interannual salinity variability using surface and subsurface salinity fields from the Met Office ENSEMBLES (EN3) quality controlled ocean dataset.It is demonstrated that during the developing phase of an El Nio event,a negative sea surface salinity (SSS) anomaly in the western-central basin acts to freshen the mixed layer (ML),decrease oceanic density in the upper ocean,and stabilize the upper layers.These related oceanic processes tend to reduce the vertical mixing and entrainment of subsurface water at the base of the ML,which further enhances the warm sea surface temperature (SST) anomalies associated with the El Nio event.However,the effects of interannually variable salinity are much more significant during the CP-El Nio than during the eastern Pacific (EP) El Nio,indicating that the salinity effect might be an important contributor to the development of CP-El Nio events.     

Warming in the northwestern Indian Ocean associated with the El Niño event

This paper investigates possible warming effects of an E1 Nifio event on the sea surface temperature anomaly （SSTA） in the northwestern Indian Ocean. Most pure positive Indian Ocean dipole （IOD） events （without an E1 Nifio event co-occurring） have a maximum positive SSTA mainly in the central Indian Ocean south of the equator, while most co-occurrences with an E1 Nifio event exhibit a northwest-southeast typical dipole mode. It is therefore inferred that warming in the northwestern Indian Ocean is closely related to the E1 Nifio event. Based on the atmospheric bridge theory, warming in the northwestern Indian Ocean during co-occurring cases may be primarily caused by relatively less latent heat loss from the ocean due to reduced wind speed. The deepened thermocline also contributes to the warming along the east coast of Africa through the suppressed upwelling of the cold water. Therefore, the E1 Nifio event is suggested to have a modulating effect on the structure of the dipole mode in the tropical Indian Ocean.     

福建省冬季暴雨过程及其环流特征

利用福建省66个气象观测站1960年12月至2008年2月的暴雨资料,分析了福建冬季暴雨的时空特征及主要影响天气系统。结果表明,冬季暴雨主要发生在闽西;福建冬季暴雨主要是南支槽东移、切变线维持和冷空气南下影响所致;冬季暴雨的产生与充沛的水汽、对流不稳定和辐合上升运动密切相关,但大气层结比汛期暴雨要稳定得多;冬季暴雨异常与500 hPa大气环流和赤道中东太平洋海温异常关系密切,它们可能主要通过大气环流的改变引起福建冬季暴雨异常。     

厄尔尼诺事件和拉尼娜事件的成因与预测

通过对南极气温资料、环南极海冰资料、臭氧变化资料、太平洋海温资料、地球自转速度变化资料、厄尔尼诺和拉尼娜资料的综合验证,发现了构造运动与厄尔尼诺因果关系。大气、海洋与岩石圈的角动量交换在南半球和北半球有不同的形式,这是由陆海分布的差异决定的。南极上空臭氧变化和环南极海冰变化是赤道海温和全球气候准两年振荡的原因。其中,德雷克海峡的海冰变化起主要作用。这个结论给出了作者提出的“海洋锅炉效应”、“臭氧洞漏能效应”、“德雷克海冰气候开关效应”和“大洋地壳跷跷板运动”的相互关系,证明构造运动对厄尔尼诺的重要影响。强潮汐准4a周期的发现,表明南极海冰变化、东太平洋海温变化、地球自转变化和厄尔尼诺都具有4a准周期变化的原因。海温和海冰开关的准2a周期和日食-厄尔尼诺系数理论有较好的预测效果。     

对ENSO循环机理的一些新认识

近几年国内学者通过资料诊断、理论分析和数值试验,对ENSO循环的机理提出了一些新的看法,其中包括El Nino和La Nina的起源,与ENSO循环相联系的暖、冷水的传播过程,热带西太平洋纬向风应力异常,以及热带东太平洋经向风应力异常在ENSO循环中的动力作用等.作者介绍了我国在这些方面的一些研究成果.     

台湾地震与大陆旱涝

利用近80年台湾、大陆和环西太平洋的地震资料,简要分析了地震场与我国东部旱涝分布的关系。台湾强震加上华北或蒙古两年内亦有强震是江淮干旱、华北涝的条件；单有台湾强震是江南旱的前兆；台湾弱震年的第一年加上长江中下游有4.5级以上地震发生是长江大涝的条件。对此统计结果从岩石圈与大气圈相互热交换的观点,提出了一个初步解释。