Agricultural Value of ENSO Information under Alternative Phase Definition

The El Niño-Southern Oscillation (ENSO) effect has been found to be associated with regional climate variations in many regions of the world, and, in turn, with variation in crop yields. Previous studies have found that early releases of ENSO phase information could permit agricultural producers to make adjustments in their decisions and in turn generate an increase in agricultural sector welfare. This study examines whether the value of the agricultural responses can be enhanced by releasing more detailed ENSO information. Namely we evaluate the implications for projected agricultural welfare under release and adaptation to the Stone and Auliciems five phase definition of ENSO states as opposed to the more standard three phase definition. This value is estimated using a stochastic, U.S./global agricultural model representing 22 climate years. The results indicate that the release and exploitation of the more detailed ENSO phase definition almost doubles the welfare impact. The results also indicate that there is room for up to another doubling of information value through further refinements.     

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ENSO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。     

一种由单值预报生成定量降水概率预报的方法及初步应用

利用1981年1月1日至2003年12月31日淮河流域59个站的降水观测及同时段美国GFS集合预报模式回算的24 h降水量集合平均预报资料,建立条件亚正态分布函数的概率预报模型并得到集成预报.针对淮河流域子流域的试验结果表明:新方法生成的集成预报的均方根误差在所有子流域和各个季节的误差都有显著降低,其中蚌埠至洪泽湖流域6月的均方根误差降低了3.11 mm.4个子流域通过该模型得到的集成预报的Brier技巧评分在0.16～0.61,说明该集成预报在整年都具有一定预报价值.在淮河上游大坡岭至息县流域,当实际日面雨量阈值为0.00～7.82 mm的预报时,夏季的集成预报出现不同程度的低报;但当实际日面雨量阈值为18.12 mm时,夏季的集成预报表现出较好的可靠性.百分位评估则进一步表明该集成预报能较好地预报出小量级的面雨量,而对30.00 mm以上面雨量的预报能力相对较弱.     

ENSO,火山活动与大气CO2的年际变化

利用大气CO2及其δ13C的观测数据分析了不同区域大气CO2的季节和年际变化特征,并结合δ13C的变化趋势判断大气CO2变化的主要影响因素是来自陆地还是海洋.结果表明:大气CO2的年际变化主要受ENSO引起的陆地植被初级生产量而不是海洋吸收变化的影响,且La Ni(n)a对大气CO2的影响大于El Ni(n)o.火山活...     

影响海南的热带气旋气候特征及其与ENSO的关系

利用1949～2003年资料,统计了影响和登陆海南热带气旋频数的时空分布特征、初、终期分布,并探讨了ENSO事件对海南省热带气旋的影响和2004年无热带气旋影响海南的原因.指出ENSO事件与海南省热带气旋活动具有显著的相关性,暖事件年有利于影响和登陆热带气旋偏少、初旋偏晚,冷事件年则相反.但ENSO事件与终旋日期相关不显著.     

河源地区气温变化特征及其与ENSO的关系

利用河源地区5个气象站1960—2016年的逐月平均气温、NOAA逐月海温等资料,采用线性倾向、Mann-Kendall检验等统计方法,分析了河源地区气温变化特征及其对ENSO事件的响应。结果表明:河源地区年平均气温及季平均气温均呈递增趋势,且夏、秋、冬季和年平均气温气温上升趋势显著;河源地区气温在20世纪80年代中后期—90年代末发生1次较为明显的由冷到暖的突变;年平均气温存在5~6、14~15及24 a的周期变化规律;在El Ni1o事件中,河源地区年平均气温有偏高趋势,La Ni1o事件,则反之;ENSO事件对气温的影响存在滞后性,对河源地区的气温影响最明显表现在次年。     

The Interannual Variations of Summer Precipitation in the Northern Indian Ocean Associated with ENSO

Using rainfall data from the Global Precipitation Climatology Project(GPCP),NOAA extended reconstruction sea surface temperature(ERSST),and NCEP/NCAR reanalysis,this study investigates the interannual variation of summer rainfall southwest of the Indian Peninsula and the northeastern Bay of Bengal associated with ENSO.The composite study indicates a decreased summer rainfall southwest of the Indian Peninsula and an increase in the northeastern Bay of Bengal during the developing phase,but vice versa during the decay phase of El Ni o.Further regression analysis demonstrates that abnormal rainfall in the above two regions is controlled by different mechanisms.Southwest of the Indian Peninsula,the precipitation anomaly is related to local convection and water vapor flux in the decay phase of El Ni o.The anomalous cyclone circulation at the lower troposphere helps strengthen rainfall.In the northeastern Bay of Bengal,the anomalous rainfall depends on the strength of the Indian southwest summer monsoon(ISSM).A strong/weak ISSM in the developing/decay phase of El Ni o can bring more/less water vapor to strengthen/weaken the local summer precipitation.     

The Value of Improved ENSO Prediction to U.S. Agriculture

The economic value of long-range weather prediction is measured by the increase in social welfare arising from the use of the prediction in economic decisionmaking. This paper describes a study of the economic value of ENSO prediction to U.S. agriculture. The interdisciplinary study involved the analysis of data and models from meteorology, plant science, and economics under a framework based on Bayesian decision analysis. The estimated annual value of perfect ENSO prediction to U.S. agriculture is $323 million.     

近百年东亚冬季风与ENSO循环的相互关系及其年代际异常

运用相关及滑动相关的计算技术，讨论了近百年东亚冬季风与ENSO循环的相互关系及其年代际异常。研究指出，东亚冬季风与赤道东太平洋海温的年际关系具有年代际的变化特征；季风与ENSO循环的关系受到季风的QBO以及季风-海洋的年代际背景场配置关系的共同作用；当季风与海洋的背景场处于同样状态时，强冬季风有利于第二年冬季赤道东太平洋的升温，产生El Ni?o事件；当两者的背景场处于反位相状态时，强冬季风对应于第二年冬季的La Ni?a位相。     

Different Impacts of Typical and Atypical ENSO on the Indian Summer Rainfall: ENSO-Developing Phase

The El Niño–Southern Oscillation (ENSO) is a main driving force of the northern hemisphere summer monsoon rainfall, including the Indian Summer Rainfall (ISR). The impacts of typical ENSO and atypical ENSO events on the ISR remain unclear during their developing summers. This study examines the different linkages between a typical ENSO and the ISR and between an a typical ENSO and the ISR. During the developing summer of a typical El Niño, negative rainfall anomalies are seen over the northeastern Indian subcontinent, while the anomalous rainfall pattern is almost the opposite for a typical La Niña; as for an atypical ENSO, the approximate “linear opposite” phenomenon vanishes. Furthermore, an anomalous global zonal wave train is found at mid-latitudes, with a local tripole circulation pattern over central–eastern Eurasia during the developing summer of a typical ENSO, which might explain the corresponding rainfall response over the Indian Peninsula. By contrast, such features are not obvious during the developing summer of an atypical ENSO. Among 106-year historical runs (1900–2005) of nine state-of-the-art models from the Coupled Model Intercomparison Project, Phase 5 (CMIP5), HadGEM2-ES exhibits promising skill in simulating the anomalous circulation pattern over mid-latitudes and central–eastern Eurasia. Probably, it is the model’s ability to capture the linkage between a typical ENSO and the ISR and the characteristics of a typical ENSO that makes the difference.     

近30a青藏高原气候与冰川变化中的两种特殊现象

近30 a全球强烈变暖,水循环加快,冰川也加剧退缩。青藏高原以其特殊的地理位置与下垫面,既对全球变暖有正常的反应,也出现了异常特殊现象。这种特殊现象已发现两处：1) 青藏高原北部偏西冰芯记录降温0.6℃,相应的冰川退缩微弱,融水径流降低;2) 青藏高原东南部以岗日嘎布山区为代表,出现较多的冰川前进,可能指示降水量有较大的增加。上述事实指示气候变化与冰川响应的复杂性。     

气候变化对冬小麦播期的影响

对驻马店市冬小麦播种期1960～2000年气象资料分析结果表明秋、冬季气温随时间升高,特别是冬小麦播种的适宜温度期逐渐推迟;1990年以后,9月25日～10月15日降水量逐渐减少,10月15～30日降水量基本与20世纪80年代持平.因此,冬小麦必须调整播期,适当晚播.     

华南霾日和雾日的气候特征及变化

利用华南192个测站1961-2008年的地面气象观测资料,采用线性趋势分析、Mann-Kendall检验、计算气候趋势系数等统计诊断方法,分析了华南年霾日、雾日的时空特征和变化.结果表明:珠江三角洲、广东西北部和广西东北部为多霾区,海南为极少霾区;华南有三个多雾区,分别位于海南中西部地区,两广的西北部地区.两广雾日呈...     

华南登陆台风频数的变化及其与ENSO事件的关系

利用 18 90～ 1999年登陆于我国的台风资料 (指热带风暴、强热带风暴及台风 ) ,主要采用小波分析方法研究华南登陆台风多时间尺度特征 ,并探讨台风与 ENSO事件的关系。结果表明 ,华南登陆台风占全国的 6 3%,平均每年 5个 (最多 10个、最少 1个 ) ,主要周期有 15、5、80年 ,在 2 0世纪 6 0年代以前 15年周期显著 ,6 0年代及以后5年周期明显。台风频数与 ENSO事件的类型及其季节有密切的关系 ,华南台风在拉尼娜年始于夏季的当年明显偏多 (比厄尔尼诺年平均多 1.8个 ) ,台风偏多年 (年频数≥ 7) ,也是拉尼娜年数多于厄尔尼诺年数。影响台风活动的因素非常复杂 ,对拉尼娜年一般可考虑当年台风可能偏多 ,但厄尔尼诺年台风偏多的可能性亦不容忽视。     

IAP ENSO预测系统预报技巧的时间依赖性及对1999年La Nia事件的预测

利用IAP ENSO预测系统对1981年11月至1997年12月系统性回报实验的结果,分析了预报技巧的时间依赖性。结果表明：该预测系统对80年代的ENSO具有较强的预报能力,在Nino 3区接近0.8的预报相关技巧（预报与观测的相关系数）可达1年半左右,而对90年代的ENSO现象,预报技巧则较低,超前半年以上的预报仅在0.4左右;预报技巧具有季节依赖性,从春季到秋初开始的预报较好,高于0.5的技巧均可维持15个月以上,其中从7月到9月开始的预报,其高于0.6的相关技巧可达16个月;而从秋末和冬季开始的预报,其技巧衰减较快,预报5个月后降到了0.5以下。对1999年La Nia事件的实时预测总体上是成功的,即此次La NNia事件将维持到2000年;但未能预测出其在1999年春季以后再次加强的过程。对其未来变化趋势的预测显示,此次La Nia事件有可能于今年夏秋季结束。     

副热带北太平洋SST在ENSO冷暖位相转变中的作用

2015/2016年发生的极端El Ni?o事件,与1997/1998年El Ni?o事件具有可比拟的强度,但是2016年事件转变为弱La Ni?a,而1998年事件则为强La Ni?a。本文通过对比这两次极端El Ni?o事件,揭示其转变为不同强度La Ni?a事件的物理机制。混合层热收支分析的结果表明,在El Ni?o衰减年的4~11月,2016年平流反馈和温跃层反馈相对较弱,混合层温度衰减速率慢,其产生的主要原因是赤道中西太平洋的东风异常较弱。进一步分析表明,赤道中西太平洋的东风异常与副热带东北太平洋的海表温度异常（SSTA）有关,该地区的SST在1998年表现为冷异常,2016年为暖异常。副热带东北太平洋冷的SSTA有利于信风加强,从而加强中西太平洋的东风异常;而暖的SSTA使得赤道以北出现西南风异常,从而削弱中西太平洋的东风异常。此外,合成分析也表明,副热带东北太平洋SSTA与转变的La Ni?a的强度具有关联,El Ni?o转变为强La Ni?a的情况在位相转变期伴随着副热带北太平洋冷的SSTA,而El Ni?o转变为弱La Ni?a的情况没有明显的冷SSTA。     

Geomorphic Variations of Debris Flows and Recent Climatic Change in the French Alps

Much work has been done to show that there is a relationship between the triggering of debris flows and the recorded increase in temperatures or in the number of intense rainy events over the last few decades. The question addressed in this paper is that of the impact of these climate changes on the dynamics of debris flows since the 1950s. 319 debris flows in the Dévoluy and Ecrins massifs located in the French Alps, the triggering of which is independent of the current glacial retreat, have been analysed. In the Dévoluy a reduction in the number of debris flows was observed in the periods 1950–1975 and 1975–2000. In the Massif des Ecrins, we have observed a shift of the triggering debris flow zone toward higher elevations and a lack of significant variation in the number of debris flows. But in the Massif des Ecrins this global result masks two different trends depending on elevation. At low altitude (<2200 m) the number of debris flows and the frequency of debris flows less than 400 m in length have decreased significantly since the 1980s whereas no significant variation was observed at high altitude (>2200 m). At the same time, we have observed a significant increase in the annual and seasonal temperatures for these 20 last years combined with a significant reduction in the number of freezing days. A significant increase in summer rains higher than 30 mm/d has also been observed. In Dévoluy and at low altitude in the Massif des Ecrins,these variations can be explained by the decrease in the number of freezing days related to the increase in the temperatures, which implies a slower reconstitution of the volume of debris stored between two events. But at high altitude it is currently difficult to establish the link between the climatic change and the dynamics of the debris flows because very little is known about the two variables controlling the triggering of the debris flows, i.e., on the one hand intense precipitations and on the other hand the volume of rock debris.     

IAP ENSO预测系统预报技巧的时间依赖性及对1999年La Nina事件的预测

利用IAPENSO预测系统对1981年11月至1997年12月系统性回报实验的结果,分析了预报技巧的时间依赖性。结果表明：该预测系统对80年代的ENSO具有较强的预报能力,在Nino3区接近0.8的预报相关技巧（预报与观测的相关系数）可达1年半左右,而对90年代的ENSO现象,预报技巧则较低,超前半年以上的预报仅在0.4左右;预报技巧具有季节依赖性,从春季到秋初开始的预报较好,高于0.5的技巧均可维持15个月以上,其中从7月到9月开始的预报,其高于0.6的相关技巧可达16个月;而从秋末和冬季开始的预报,其技巧衰减较快,预报5个月后降到了0.5以下。对1999年La nina事件的实时预测总体上是成功的,即此次La nina事件将维持到2000年;但未能预测出其在1999年春季以后再次加强的过程。对其未来变化趋势的预测显示,此次La nina事件有可能于今年夏秋季结束。     

南繁的农业气候条件分析与利用

分析三亚市南繁期间(10月至次年4月)的农业气候条件及气象灾害,并提出开发利用的建议。