Chinese Contribution to CMIP5：An Overview of Five Chinese Models’Performances

An overview of Chinese contribution to Coupled Model Intercomparison Project-Phase 5 （CMIP5） is presented. The performances of five Chinese Climate/Earth System Models that participated in the CMIP5 pro ject are assessed in the context of climate mean states, seasonal cycle, intraseasonal oscillation, interan-nual variability, interdecadal variability, global monsoon, Asian-Australian monsoon, 20th-century historical climate simulation, climate change pro jection, and climate sensitivity. Both the strengths and weaknesses of the models are evaluated. The models generally show reasonable performances in simulating sea surface tem-perature （SST） mean state, seasonal cycle, spatial patterns of Madden-Julian oscillation （MJO） amplitude and tropical cyclone Genesis Potential Index （GPI）, global monsoon precipitation pattern, El Ni-no-Southern Oscillation （ENSO）, and Pacific Decadal Oscillation （PDO） related SST anomalies. However, the perfor-mances of the models in simulating the time periods, amplitude, and phase locking of ENSO, PDO time periods, GPI magnitude, MJO propagation, magnitude of SST seasonal cycle, northwestern Pacific mon-soon and North American monsoon domains, as well as the skill of large-scale Asian monsoon precipitation need to be improved. The model performances in simulating the time evolution and spatial pattern of the 20th-century global warming and the future change under representative concentration pathways pro jection are compared to the multimodel ensemble of CMIP5 models. The model discrepancies in terms of climate sensitivity are also discussed.     

长江流域径流量变化过程及其对ENSO和PDO的响应

根据宜昌站、汉口站和大通站的径流量数据,运用M-K检验和小波分析等方法,对1900年以来长江流域径流量的趋势和周期变化进行分析,探究径流量变化对厄尔尼诺?南方涛动（ENSO）和太平洋年代际振荡（PDO）的响应。结果表明：1900 年以来长江流域径流量呈显著的减少趋势,并具有2~8 a的年际周期变化和14~17 a的年代际周期变化。流域径流量与ENSO具有相同的2~8 a周期变化,在El Ni?o发生期,径流量较低,在La Ni?a发生期,径流量较高。14~17 a的周期变化与PDO相关,在暖位相期径流量偏少,在冷位相期径流量偏多。PDO影响着ENSO和径流量之间的相关性,在暖位相期,El Ni?o对径流量的影响增强,在冷位相期,La Ni?a对径流量的影响增强。因此,在分析和预测流域径流量长时间尺度上的变化时要综合考虑ENSO和PDO的影响。     

SST variations of the Kuroshio from AVHRR observation

1 INTRODUCTION The Kuroshio Current (KC), being the western boundary current in the North Pacific subtropical gyre, is the second strongest current in the world af- ter the Gulf Stream and is famous as a strong and fast flow. KC plays an important role in…     

PRECIPITATION PATTERNS IN FLOOD SEASON OVER CHINA ASSOCIATED WITH THE EL NI■O/SOUTHERN OSCILIATION

I.I~IOXENds(EINabs/SouthernOscillation)eventsaretheintensivesignalsofair-seainteractionintropicalarea.PlentyOfresultsfromdifferentresearchersshoWthattheENdssignalcanbedetectedoninterannualvallationsoflargescaleatmOSPhericcirculationandclimateregimeSovermostpartsoftheworld.SeveralkindsofrelationShipbetweenENdsandprecipitationoverChinahavebeenrevealedbydifferentreSearcherS,buttherearemanydifferencesamongthepublishedreSults.Itmayberesulted*fromthatdifferentreSearchersuseddifferentindic…     

Holocene initiation and expansion of the southern margins of northern peatlands triggered by the East Asian summer monsoon recession

Northern peatlands represent one of the largest biospheric carbon reservoirs in the world. Their southern margins act as new carbon reservoirs, which can greatly influence the global carbon dynamics. However, the Holocene initiation, expansion and climate sensitivity of these peatlands remain intensely debated. Here we used a compilation of basal peat ages across six isolated peatlands at the southern margins of northern peatlands to address these issues. We found that the earliest initiation event of these peatlands occurred after the Younger Dryas (YD, 12,800–11,700 years ago) period. The second initiation event and rapid expansion occurred since 5 ka cal. BP. The recession of East Asian summer monsoon (EASM) during the YD period and at around 5 ka cal. BP likely played a major role in controlling the initiation and expansion of these peatlands. The rapid expansion of these peatlands possibly contributed to the significant increases in atmospheric methane concentrations during the late Holocene because of the minerotrophic fens status and rapid expansion of them. These ecological processes are different from northern peatlands, indicating the special carbon sink and source implications of these peatlands in the global carbon cycle.     

在ENSO不同位相下青藏高原春季感热对华南盛夏降水的影响

根据青藏高原(简称高原)春季感热(Sensible Heat,SH)异常和ENSO不同位相,划分出12种类型,研究了高原春季(5月)SH异常和前冬ENSO对华南盛夏(7—8月)降水的影响及相对影响程度。结果表明:高原春季SH和前冬ENSO均对华南盛夏降水有较显著的影响,即当两者分别处于各自正(负)位相时,华南盛夏降水普遍偏少(多);通过对两者的单独作用和协同作用的分析表明,高原春季SH对华南盛夏降水贡献要更大。影响机制分析发现华南盛夏降水受西太平洋副热带高压(简称西太副高)和南亚高压共同影响,ENSO直接影响西太副高,而高原春季SH异常则对南亚高压作用显著,因此在两者共同影响下,两个高压的变化共同导致华南盛夏降水出现异常。      

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.     

Two Opposite Extreme Events in Seasonal Mean Winter Rainfall over East China during the Past Three Decades

In this study,the extremes of winter seasonal mean precipitation have been investigated by using daily precipitation data from 91 stations in East China,the National Centers for Environmental Prediction/the National Center for Atmospheric Research(NCEP/NCAR)monthly reanalysis,and sea surface temperature data from the Hadley Centre for 1979–2007.The largest anomalous rainfall amount was observed in regions south of the Yangtze River.In the most recent three decades,extreme events in the seasonal mean winter precipitation occurred in 1985 and 1997.Because it was influenced mainly by a La Ni a event,the precipitation in 1985 showed a deficit following a stronger winter monsoon.The rainfall amount in 1997 was influenced by El Ni o and was significantly larger than normal with a weaker winter monsoon.Both the circulation anomalies and wave energy dispersions during the winters of 1985 and 1997 differed significantly.In 1985,the North Atlantic Oscillation anomalously excited the Eurasian-Pacific teleconnection and circumglobal teleconnection phenomena.Consequently,Rossby wave energy propagated along the north and south branches of the westerlies,strengthening the East Asian trough along with a stronger winter monsoon,which facilitated the wintertime dry extreme in East China.In1997,however,Rossby wave energy propagated from low latitudes northeastward into the southern part of China,resulting in a weaker winter monsoon and the wettest winter.The results of this study will be helpful for future monitoring and prediction of extreme winter rainfall events in East China.     

ENSO发展和衰减阶段的陕西夏季降水异常特征

利用1961—2008年陕西78个气象站夏季 (6—8月) 降水资料、NCEP/NCAR位势高度场和风场月平均再分析资料,采用合成及相关分析方法探讨ENSO发展和衰减阶段对陕西夏季降水异常的影响,以期为陕西夏季降水的气候预测提供线索和依据。结果表明:陕西夏季降水异常对ENSO发展和衰减阶段的响应存在显著差异,El Ni?o发展阶段和La Ni?a衰减阶段,陕西夏季降水偏少; El Ni?o衰减阶段和La Ni?a发展阶段,陕西夏季降水偏多; ENSO不同阶段对陕西7月降水影响最为显著。比较而言,El Ni?o事件对陕西夏季降水的影响更加显著。在El Ni?o衰减、La Ni?a发展阶段,西太平洋副热带高压偏强、偏西,东亚夏季风偏弱,而在El Ni?o发展、La Ni?a衰减阶段,西太平洋副热带高压偏弱、偏东,东亚夏季风偏强,El Ni?o过程对东亚夏季风强弱的影响更加显著。ENSO发展和衰减阶段通过影响大气环流变化和东亚夏季风的强弱,进而影响陕西夏季降水。     

亚洲区域海—陆—气相互作用对全球和亚洲气候变化的作用研究进展

围绕全球变化研究国家重大研究计划项目“亚洲区域海—陆—气相互作用机理及其在全球变化中的作用”预定的总体研究内容和科学目标,项目执行两年多以来,取得了一系列阶段性科研成果.关于气候动力学方面,项目揭示了热带印度洋—西太平洋暖池的海温变化是全球热带气候年代际变化的重要驱动力,是全球尺度副热带干旱的重要调控器;发现热带东太平洋海温存在冷舌模态,它是一个海气耦合模态,阐明在全球变暖背景下其对ENSO型态变异的作用及影响东亚气候的机理;揭示了青藏高原热力强迫的异常特征及其气候效应;提出了水平非均匀基流中行星波传播的理论,研究了其在不同东亚夏季风背景下的传播特征.关于气候预测方法方面,提出了若干有物理基础的气候预测方法,如尺度分离的降尺度预测新方法、基于北大西洋涛动(NAO)-ENSO的东亚夏季风预测模型、基于南半球环状模的东亚气候预测模型等,为业务部门提供了重要参考.关于观测方面,项目在亚洲区域海气补充观测和海洋资料同化方面也取得突出进展,成功进行了南海18°N断面海洋综合观测,为形成我国第一条南海断面长期海气观测打下了基础.在国际合作方面,项目还继续推动和领导了“亚洲季风年”(AMY2007-2012)与“东亚气候模拟”国际计划,提升了我国在该领域的国际地位.