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Impacts of major volcanic eruptions over the past two millennia on both global and Chinese climates:A review

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Science China Earth Sciences 2024年第1期67卷 61-78页

作者： Weiyi SUN Deliang CHEN Guonian LÜ Liang NING Chaochao GAO renhe zhang Bin WANG Jian LIU Key Laboratory for Virtual Geographic Environment Ministry of EducationState Key Laboratory Cultivation Base of Geographical Environment Evolution of Jiangsu ProvinceJiangsu Center for Collaborative Innovation in Geographical Information Resource Development and ApplicationSchool of Geography ScienceNanjing Normal UniversityNanjing 210023China Regional Climate Group Department of Earth SciencesUniversity of GothenburgGothenburg 40530Sweden College of Environmental and Resource Science Zhejiang UniversityHangzhou 310058China Department of Atmospheric and Oceanic Sciences&Institute of Atmospheric Sciences Fudan UniversityShanghai 200437China Department of Atmospheric Sciences and Atmosphere-Ocean Research Center University of Hawaii at ManoaHonoluluHI 96825USA Jiangsu Provincial Key Laboratory for Numerical Simulation of Large Scale Complex Systems School of Mathematical ScienceNanjing Normal UniversityNanjing 210023China Open Studio for the Simulation of Ocean-Climate-Isotope Qingdao National Laboratory for Marine Science and TechnologyQingdao 266237China

Major volcanic eruptions(MVEs)have attracted increasing attention from the scientific community.Previous studies have explored the climatic impact of MVEs over the past two millennia.However,proxy-based reconstructions and climate model simulations indicate divergent responses of global and China’s regional climates to MVEs.Here,we used multiple data from observations,reconstructions,simulations,and assimilations to summarize the historical facts of MVEs,the characteristics and mechanisms of their climatic impact,and directions for future research.We reviewed volcanic datasets and determined intensive MVE periods;these periods corresponded to the years 530–700,1200‒1460,and 1600‒1840 CE.After tropical MVEs,a substantial cooling effect is observed throughout the globe and China on the interannual-interdecadal time scales but an inconsistent cooling magnitude is detected between reconstructions and simulations.In the first summer after tropical MVEs,a decrease in global and monsoonal precipitation is observed.In reconstructions and simulations,an increased precipitation is seen for the Yangtze River Basin,while large uncertainties in precipitation changes are present for other regions of China.Decadal drought can be induced by frequent eruptions and volcanism superimposed on low solar irradiation and internal variability.MVEs affect climate directly through the radiative effect and indirectly by modulating internal variability,such as the El Niño‒Southern Oscillation(ENSO)and Atlantic Multidecadal Oscillation(AMO).However,changes in the phase,amplitude,and periodicity of ENSO and AMO after MVEs and the associated mechanisms remain controversial,which could account for model-reconstruction disagreements.Moreover,other internal variability,uncertainties in reconstruction methods and aerosol‒climate models,and climate background may also induce model-reconstruction disagreements.Knowledge gaps and directions for future research are also discussed.

关键词： Major volcanic eruption Climate variability Mechanism Past two millennia Internal variability

Exact solution of three-dimensional acoustic field in a wedge with perfectly reflecting boundaries

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Science China(Physics,Mechanics & Astronomy) 2015年第9期58卷 29-38页

作者： LUO WenYu zhang renhe State Key Laboratory of Acoustics Institute of Acoustics Chinese Academy of Sciences

An exact approach is presented to compute the three-dimensional(3D) acoustic field in a homogeneous wedge-shaped ocean with perfectly reflecting boundaries. This approach applies the Fourier synthesis technique, which reduces a 3D point-source ideal wedge problem into a sequence of two-dimensional(2D) line-source ideal wedge problems, whose analytical solution is well established. A comparison of numerical efficiency is provided between this solution and the solution proposed by Buckingham,which is obtained by a sequence of integral transforms. The details of numerical implementation of these two solutions are also given. To validate the present approach and at the same time compare numerical efficiency between this approach and Buckingham's analytical solution, two numerical examples are considered. One is the Acoustical Society of America(ASA) benchmark wedge problem and the other is a wide-angle wedge problem. Numerical results indicate that the present approach is efficient and capable of providing accurate 3D acoustic field results for arbitrary receiver locations, and hence can serve as a benchmark model for sound propagation in a homogeneous wedge-shaped ocean.

关键词：三维声场反射边界精确解数值结果基准模型合成技术积分变换声学学会

Temporal and spatial features of the soil moisture in boreal spring in eastern China

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Science China Earth Sciences 2009年第2期52卷 269-278页

作者： ZUO ZhiYan zhang renhe State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China

Soil moisture data of 45 years from European Center for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-40) and the in situ observational data are used to study the temporal and spatial characteristics of the soil moisture in boreal spring in the area to the east of 100°E in China. Results show that ERA-40 soil moisture well reproduces the temporal and spatial features of observations. ERA-40 data capture the spatial pattern that the soils in Northeast China and Southwest China are wetter than those in Inner Mongolia and North China and represent the inter-annual variability in ob-servations. The dry trends of spring soil moisture are evident over the whole eastern China. It is espe-cially prominent for the dry trend in southwest China where the spring soil from surface to deep-layer show drying and the trend became significant after the 1980s. The dry trend in Northeast China is weak after early 1970s in near-surface layer but aggravates after latel 1970s in deep layers. In the mid-latitude zone, the inter-annual variation of spring soil is robust and shows no dry trend except in deep-layer after 1988.

关键词： soil moisture 100°E east of China spring temporal and spatial variation

Three-dimensional mode coupling around a seamount

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Science China(Physics,Mechanics & Astronomy) 2011年第9期54卷 1561-1569页

作者： LUO WenYu zhang renhe SCHMIDT Henrik State Key Laboratory of Acoustics Institute of Acoustics Chinese Academy of Sciences Beijing 100190 China Department of Mechanical Engineering Massachusetts Institute of Technology Massachusetts 02139 USA

A recently developed three-dimensional normal-mode model is adopted to investigate mode coupling around a seamount in a deep water environment. As indicated by the theoretical analysis and verified by the numerical results, strong mode coupling occurs at the edge of a seamount under certain conditions. Therefore, mode coupling is critical for the investigation of the acoustic field in the presence of a seamount. In addition, the issue regarding the number of sectors assuring convergence is also presented. This issue is important in a two-way coupled-mode approach, especially for solving three-dimensional problems, because the computational effort increases dramatically with the number of sectors in representing a varying bathymetry. The theoretical analysis as well as the numerical example in this paper shows that artificial diffraction lobes form in the event that uniform discretization is used with a horizontal step size greater than half of the acoustic wavelength. However, by using random discretization instead, such artificial diffraction lobes are diffused, resulting in a faster convergence rate.

关键词：三维问题耦合模式海山模式耦合数值结果收敛速度水环境正常模

A modified warping operator based on BDRM theory in homogeneous shallow water

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Science China(Physics,Mechanics & Astronomy) 2014年第3期57卷 424-432页

作者： NIU HaiQiang zhang renhe LI ZhengLin State Key Laboratory of Acoustics Institute of AcousticsChinese Academy of Sciences University of Chinese Academy of Sciences Haikou Laboratory of Acoustics Institute of AcousticsChinese Academy of Sciences

In this paper,a modified warping operator for homogeneous shallow water based on the Beam-Displacement Ray-Mode(BDRM)theory is presented.According to the BDRM theory,the contribution of the beam displacement and the time delay to the group velocity can be easily considered in a shallow water waveguide.A more accurate dispersion formula is derived by using the cycle distance formula to calculate the group velocity of normal modes.The derived dispersion formula can be applied to the homogeneous shallow water waveguide.Theoretically,the formula is related to the phase of the reflection coefficient and suitable for various bottom models.Furthermore,based on the derived dispersion relation,the modified warping operator is developed to obtain linear modal structures.For the Pekeris model,the formulae for the phase of the reflection coefficient are derived in this work.By taking account of the effect of the bottom attenuation on the reflection coefficient,the formula for the phase of the reflection coefficient including the bottom attenuation is obtained for the Pekeris model with a lossy bottom.Performance and accuracy of different formulae are evaluated and compared.The numerical simulations indicate that the derived dispersion formulae and the modified warping operator are more accurate.

关键词： BDRM理论运营商翘曲修改浅水均匀反射系数色散关系

ATTENUATION AND GROUP VELOCITY OF NORMAL MODE IN AN ISO-VELOCITY SHALLOW WATER

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Chinese Journal of Acoustics 1989年第2期8卷 121-132页

作者： zhang, renhe Lu, Zhengfeng Shanghai Acoustics Lab Shanghai China

Proceeding from the eigenvalue equation of the normal mode in homogeneous shallow water, we derive several formulae calculating the mode attenuation and group velocity, and compare their accuracy by means of numerical results. The paper especially discusses the attenuation and the group velocity of critical mode in a Pekeris channel and shows that in general, the attenuation and the group velocity of the critical mode respectively are less than the absorption and the sound speed in the bot -torn . Therefore, the Kornhauser, Raney, Weston Tindle ' s conclusions are modified that the attenuation and the group velocity of the critical mode are exactly equal to the absorption and the sound speed in the bottom, respectively.

关键词： Acoustic Variables Measurement Wave Velocity Acoustic Waves Attenuation Mathematical Techniques Eigenvalues and Eigenfunctions

Interdecadal shift in the western North Pacific Summer SST anomaly in the late 1980s

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Chinese Science Bulletin 2007年第18期52卷 2559-2564页

作者： WU BingYi zhang renhe Chinese Academy of Meteorological Sciences Beijing 100081 China State Key Laboratory of Cryospheric Science Chinese Academy of Sciences Lanzhou 730000 China

An interdecadal shift in summer (June―August) sea surface temperature (SST) variations during the period of 1968―2002 was identified in the late 1980s, which is characterized by a phase alternating from negative to positive phases of the leading mode of the empirical orthogonal function (EOF) analysis of the summer monthly mean SST in the Pacific domain 100°―180°E and 0°―40°N, accounting for 30.5% of the total variance. During the period of 1968―1987, the leading mode with a mean negative phase state (mean standard deviation = ?0.586) controlled SST variability in the western North Pacific. Correspondingly, negative SST anomalies occupied the western North Pacific south of Japan and Chinese marginal seas. During the period of 1988―2002, the leading mode shifted to its strong positive polarity (mean standard deviation = 0.781), thus positive SST anomalies appeared in the western North Pacific. Accompanied by the interdecadal shift in summer mean SST, summer mean rainfall increased in southern and southeastern China during the late period, particularly in southeastern China where increase in summer mean rainfall exceeded 40 mm, at the 0.05 significance level.

关键词：北太平洋海洋表层温度十年际变化夏季八十年代

Interference structure of shallow water reverberation in time-frequency distribution

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Science China(Physics,Mechanics & Astronomy) 2010年第8期53卷 1408-1411页

作者： LI FengHua zhang YanJun zhang renhe LIU JianJun National Laboratory of Acoustics Institute of AcousticsChinese Academy of SciencesBeijing 100190China Graduate University of Chinese Academy of Science Beijing 100190China

The striations of the reverberation spectrum in the time-frequency distribution were observed in a shallow water acoustic experiment in 2002. A model following the coherent reverberation model developed in 2002 is presented to explain the observed striations. To examine the consistency between the measured data and numerical predictions, we have used a method based on Radon transform for determining the slope of the striations to the measured reverberation data and numerical predictions. The results indicate that the previously developed coherent reverberation model can predict the interference structure of the reverberation intensity in the time-frequency distribution.

关键词： reverberation interference time-frequency waveguide invariant

Impacts of Atlantic sea surface temperature anomalies on Indo-East Asian summer monsoon-ENSO relationship

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Chinese Science Bulletin 2010年第22期55卷 2458-2468页

作者： RONG XinYao zhang renhe LI Tim Chinese Academy of Meteorological Sciences Beijing 100086 China International Pacific Research Center and Department of Meteorology University of Hawaii at Manoa Honolulu HI 96822 USA

In this study, the effect of the tropical North Atlantic (TNA) sea surface temperature (SST) variation in inducing the circulation anomaly in the Indo-East Asian monsoon (IEAM) region is investigated through the observational analysis and numerical model-ing. The observational analysis shows that the TNA summer SST is positively correlated with the preceding winter Ni?o3 SST and is simultaneously correlated with the circulation in the IEAM region. The simultaneous circulation pattern resembles that of the ENSO-decaying summer. The positive correlation between the TNA SST and the Ni?o3 region SST is primarily ascribed to the surface latent heat flux and short wave radiation anomalies induced by the ENSO teleconnection. Coupled general circulation model experiments show that, while including the air-sea coupling in the Atlantic, the model can reproduce the main features of the IEAM circulation, such as an anomalous anticyclone over the western North Pacific (WNP) and southerly anomalies over southeast China. While the climatological Atlantic SST is prescribed, the circulation over the WNP displays a significantly dif-ferent pattern, with an eastward migration of the WNP anticyclone and the associated northerly anomalies over southeast China. It is argued that anticyclonic shear and Ekman divergence associated with the atmospheric Kelvin wave response to the TNA warm SSTA forcing is the primary mechanism for the generation of the anomalous anticyclone in WNP. The results presented in this study provide a teleconnection pattern between TNA and short-term climate variability in IEAM region.

关键词：海表温度异常北大西洋 ENSO 东亚季风夏季季风短期气候变化中国东南部西北太平洋