ENSO冷暖事件与郑州地区汛期气候异常关系

利用1951—2000年郑州站汛期气温和降水资料，分析了ENSO冷暖事件与郑州地区汛期气候异常的关系。结果发现：ENS0冷暖事件对郑州地区汛期降水和气温均有较大影响，对降水异常的影响更显著。暖事件出现当年，郑州地区汛期易出现降水异常偏少，次年则易出现降水异常偏多；冷事件出现当年，郑州地区汛期降水易出现异常偏多，次年降水出现异常的几率较小。     

ENSO signals and their spatial-temporal variation characteristics recorded by the sea-level changes in the northwest Pacific margin during 1965–2005

Sea-level is closely linked to the Earth’s climate and its change is important as a metric for global and regional climate change. Identifying, extracting, and revealing such information through detailed analysis is the prerequisite for understanding the mechanisms of sea-level change. The monthly- average tide-change records reported and examined in this paper are from 10 tide gauge stations distributed in the northwest margin of the Pacific Ocean, registered during the period 1965-2005. In particular, we have utilized the Second Order Blind Identification (SOBI) method to identify and the Empirical Mode Decomposition (EMD) method to extract the El Niño-Southern Oscillation (ENSO) signals imprinted in those tide gauge records; and subsequently, we have investigated the spatial-temporal characteristics of the extracted ENSO signals using wavelet analysis methods. The following results are obtained: (1) the ENSO events recorded by each tide gauge series are of different types and intensity, which show considerable temporal-spatial variation characteristics, with sea-level responses to ENSO signals remarkably stronger in low latitude areas than in medium-high latitude areas; (2) due to the influences of ocean currents, topographical conditions, and other factors, there exist variations in the type of relationship between the sea-level changes and the recorded ENSO events at different latitudes; (3) sea-level changes can also denote scale-variation characteristics of ENSO events, and particularly, since 1980s, all the tide gauges located south of Kanmen show intense responses to ENSO and the timescale of ENSO events extended gradually from around 4 years to 2–8 years, reflecting variations in the intensity and frequency of ENSO events; and (4) reverse changes of certain scale were noted before and after strong ENSO events recorded by sea-level changes, supporting the research findings about the interaction (mutual coupling and superimposition) between the probability of occurrence of strong ENSO events and their time scale.     

ENSO signals and their spatial-temporal variation characteristics recorded by the sea-level changes in the northwest Pacific margin during 1965-2005

Sea-level is closely linked to the Earth's climate and its change is important as a metric for global and regional climate change. Identifying, extracting, and revealing such information through detailed analysis is the prerequisite for understanding the mechanisms of sea-level change. The monthlyaverage tide-change records reported and examined in this paper are from 10 tide gauge stations distributed in the northwest margin of the Pacific Ocean, registered during the period 1965-2005. In particular, we ha...     

宁夏降水变化及其与ENSO事件的关系

分析1959~2001年的月降水数据发现:20世纪60~80年代宁夏降水有较明显的干旱趋势,但90年代降水较80年代有所增加。功率谱分析表明,ENSO和宁夏降水具有一致的变化周期,即14年、3.75年、准2年和1.5年。宁夏降水对EL Nino事件达到最显著响应需要滞后2~4个月,而对LA Nina事件的响应比对EL Nina迅速,只需滞后1~2个月便达到最显著响应。ENSO对宁夏不同季节降水的影响差异很大。EL Nino发生4个月后,春、夏、秋三个季节降水都偏少,但冬季降水却是增加了。LA Nina发生1个月后,夏、秋、冬三个季节降水都偏多,但春季降水减少了。EL Nino事件发生期间,宁夏年降水偏少28 mm,占常年降水量的10%,而LA Nina发生期间,年降水偏多24 mm,占年降水量9%。     

印尼贯穿流源区马鲁古海与哈马黑拉海水团来源的季节和年际变化

So far, large uncertainties of the Indonesian throughflow(ITF) reside in the eastern Indonesian seas, such as the Maluku Sea and the Halmahera Sea. In this study, the water sources of the Maluku Sea and the Halmahera Sea are diagnosed at seasonal and interannual timescales and at different vertical layers, using the state-of-the-art simulations of the Ocean General Circulation Model(OGCM) for Earth Simulator(OFES). Asian monsoon leaves clear seasonal footprints on the eastern Indonesian seas. Consequently, the subsurface waters(around 24.5σ_θ and at ～150 m) in both the Maluku Sea and the Halmahera Sea stem from the South Pacific(SP) during winter monsoon, but during summer monsoon the Maluku Sea is from the North Pacific(NP), and the Halmahera Sea is a mixture of waters originating from the NP and the SP. The monsoon impact decreases with depth, so that in the Maluku Sea, the intermediate water(around 26.8σ_θ and at ～480 m) is always from the northern Banda Sea and the Halmahera Sea water is mainly from the SP in winter and the Banda Sea in summer. The deep waters(around27.2σ_θ and at ～1 040 m) in both seas are from the SP, with weak seasonal variability. At the interannual timescale,the subsurface water in the Maluku Sea originates from the NP/SP during El Ni?o/La Ni?a, while the subsurface water in the Halmahera Sea always originates from the SP. Similar to the seasonal variability, the intermediate water in Maluku Sea mainly comes from the Banda Sea and the Halmahera Sea always originates from the SP. The deep waters in both seas are from the SP. Our findings are helpful for drawing a comprehensive picture of the water properties in the Indonesian seas and will contribute to a better understanding of the ocean-atmosphere interaction over the maritime continent.     

印度尼西亚海及周边海域层结的时空变化特征分析

本文利用World Ocean Atlas 2013 (WOA13)和Simple Ocean Data Assimilation version 3.1.1 (SODA v3.3.1)温盐资料,分析印尼贯穿流(ITF)路径及所经印度尼西亚海及周边西太平洋、南海和东印度洋海域的层结强度(N²)和跃层特征的三维时空变化特征。结果表明,气候态下ITF 3条路径上跃层平均N²差异较小,其中中部路径平均值最大,为10^−3.68 s⁻²,东部路径平均值最小,为10^−3.71 s⁻²;各路径跃层深度和厚度存在明显差异,东部路径跃层深度和厚度最大,分别为124 m和192 m,中部次之,西部最小为99 m和143 m,并且印尼海的跃层深度和厚度平均值均小于其他海域。印尼海N²存在显著的季节变化和4～7 a的多年周期变化,其中年际变化可能主要受厄尔尼诺−南方涛动事件影响。季节上,在印尼海域内,ITF 3条路径夏季层结强度均小于冬季(北半球夏冬季),夏、冬两季N²差值最大可达到两个量级。1993−2015年的长期变化趋势显示,印尼海及周边大部分海域的层结强度呈现增强趋势,其中印度洋中部和哈马黑拉海23 a内最大层结增强近0.1个量级。     

南印度洋副热带偶极模在ENSO事件中的作用

南印度洋副热带偶极模（Subtropical Dipole Pattern,SDP）是印度洋存在的另一种很明显的偶极型海温差异现象,在年际和年代际尺度上均有十分明显的表现.而目前有关印度洋海气相互作用的研究主要集中在赤道印度洋地区,针对南印度洋地区的工作还比较少,特别是有关南印度洋海温与ENSO（El NiDo-Southern Oscillation）事件关系的研究.本文初步探讨了年际尺度上南印度洋副热带偶极型海温变化差异与ENSO事件的关系,发现SDP与ENSO事件有密切的联系,SDP事件就像连接正负ENSO位相转换的一个中间环节,SDP事件前后期ENSO的位相刚好完全相反.进一步,本文通过分析SDP事件前后期海温、高低层风、低层辐合辐散、高空云量和辐射等的变化特征研究了南印度洋偶极型海温异常在ENSO事件中的作用,结果表明：SDP在ENSO事件中的作用不仅涉及海气相互作用的正负反馈过程,还与热带和副热带大气环流之间的相互作用有关,特别是与东南印度洋海温变化所引起的异常纬向风由赤道印度洋向赤道太平洋传播的过程等有十分直接的关系;同时,SDP对ENSO事件的影响在很大程度上还依赖于大尺度平均气流随季节的变换.     

ENSO对平流层气溶胶分布的影响

本文采用ONI(Oceanic Nino Index)和HALOE(Halogen Occultation Experiment)气溶胶面积密度资料,从其滞后相关性入手分析了ENSO循环对平流层气溶胶的影响,通过对滞后于El Nino和La Nina时气溶胶含量的比较探讨了ENSO强迫的影响程度,并用剩余环流及其输送量解释了平流层气溶胶变化的动力机制.结果表明:ENSO对平流层气溶胶的分布有明显影响,在赤道和低纬度上空尤为显著,El Nino发生后半年内热带平流层低层的气溶胶面积密度较平均值偏大,平流层中层的面积密度则偏小,而La Nina反之.El Nino和La Nina影响的差异显著,在分别滞后于El Nino和La Nina事件2~8个月间的60 hPa气溶胶含量差异甚至高达45%,海表温度变化1 K则在滞后半年内气溶胶面积密度的变化可达到16%.ENSO的强烈影响能够维持大约半年,两年后基本消退.热带的变化幅度明显强于中高纬度,南北半球的变化特征也有所不同.ENSO通过影响剩余环流导致气溶胶输送量发生变化,进而引起气溶胶分布出现上述差异.     

近40年中国区域的气候型变化与北半球大气环流特征10年际时空变化的关系

根据１８００－１９８９年（１１０年）的资料，分析研究了新加坡地区月平均和年平均降雨量的一些特征。主要结论是：新加坡年平均降雨量存在准２－６年和１８年的周期振荡；亚洲季风以及ＥＮＳＯ对新加坡降雨量有明显的影响。新加坡年雨量的谷值出现在西南季风期而峰值在东北季风期。在Ｅｌ Ｎｉｎｏ年，新加坡降雨量多为负距平；而在反Ｅｌ Ｎｉｎｏ年，新加坡降雨量多为正距平。     

Preliminary Studies on Predicting the Tropical Indian Ocean Sea Surface Temperature through Combined Statistical Methods and Dynamic ENSO Prediction

The sea surface temperature(SST) in the Indian Ocean affects the regional climate over the Asian continent mostly through a modulation of the monsoon system.It is still difficult to provide an a priori indication of the seasonal variability over the Indian Ocean.It is widely recognized that the warm and cold events of SST over the tropical Indian Ocean are strongly linked to those of the equatorial eastern Pacific.In this study,a statistical prediction model has been developed to predict the monthly SST over the tropical Indian Ocean.This model is a linear regression model based on the lag relationship between the SST over the tropical Indian Ocean and the Ni o3.4(5°S-5°N,170°W-120°W) SST Index.The predictor(i.e.,Ni o3.4 SST Index) has been operationally predicted by a large size ensemble El Ni o and the Southern Oscillation(ENSO) forecast system with coupled data assimilation(Leefs_CDA),which achieves a high predictive skill of up to a 24-month lead time for the equatorial eastern Pacific SST.As a result,the prediction skill of the present statistical model over the tropical Indian Ocean is better than that of persistence prediction for January 1982 through December 2009.