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Glacial thermohaline circulation and Climate:Forcing from the North or South?

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Advances in Atmospheric Sciences 2006年第2期23卷 199-206页

作者： Zhengyu LIU Center for Climatic Research/GNIES University of Wisconsin-Madison WI53706 USA Institute of Earth Environment Chinese Academy of Sciences Xi＇an 710075

Based on the evidence available from both observations and model simulations, the author proposes a view that may provide a unified interpretation of the North Atlantic thermohaline variability. Because of the slow response time of the Southern Ocean （millennia） and the relatively faster response time of the North Atlantic （centuries）, the North Atlantic thermohaline circulation is controlled predominantly by the climate forcing over the Southern Ocean at the long glacial cycle timescales, but by the North Atlantic climate forcing at the short millennial timescaies.

关键词： interhemispheric interaction thermohaline circulation glacial cycle millennial variability

Abrupt Climate Change around 4 ka BP:Role of the thermohaline circulation as Indicated by a GCM Experiment

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Advances in Atmospheric Sciences 2004年第2期21卷 291-295页

作者：王绍武周天军蔡静宁朱锦红谢志辉龚道溢 Department of Atmospheric Sciences School of Physics Peking University Beijing 100871 State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 Department of Atmospheric Sciences School of Physics Peking University. Beijing 100871 Key Lab of Environmental Change and Natural Disaster Ministry of Education Institute of Resources Science Beijing Normal University Beijing 100875

A great deal of palaeoenvironmental and palaeoclimatic evidence suggests that a predominant temperature drop and an aridiflcation occurred at ca. 4.0 ka BP. Palaeoclimate studies in China support this dedution. The collapse of ancient civilizations at ca. 4.0 ka BP in the Nile Valley and Mesopotamia has been attributed to climate-induced aridification. A widespread alternation of the ancient cultures was also found in China at ca. 4.0 ka BP in concert with the collapse of the civilizations in the Old World. Palaeoclimatic studies indicate that the abrupt climate change at 4.0 ka BP is one of the realizations of the cold phase in millennial scale climate oscillations, which may be related to the modulation of the thermohaline circulation (THC) over the Atlantic Ocean. Therefore, this study conducts a numerical experiment of a GCM with SST forcing to simulate the impact of the weakening of the THC. Results show a drop in temperature from North Europe, the northern middle East Asia, and northern East Asia and a significant reduction of precipitation in East Africa, the Middle East, the Indian Peninsula, and the Yellow River Valley. This seems to support the idea that coldness and aridification at ca. 4.0 ka BP was caused by the weakening of the THC.

关键词： abrupt climate change 4 ka BP thermohaline circulation collapse of ancient civilization

Three-Dimensional Structure of Optimal Nonlinear Excitation for Decadal Variability of the thermohaline circulation

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Atmospheric and Oceanic Science Letters 2013年第6期6卷 410-416页

作者： ZU Zi-Qing MU Mu Henk A.DIJKSTRA State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG) Institute of Atmospheric Physics Chinese Academy of Sciences University of Chinese Academy of Sciences Key Laboratory of Ocean circulation and Wave Institute of Oceanology Chinese Academy of Sciences Institute for Marine and Atmospheric Research Utrecht Department of Physics and Astronomy Utrecht University

The decadal variability of the North Atlantic thermohaline circulation(THC) is investigated within a three-dimensional ocean circulation model using the conditional nonlinear optimal perturbation method. The results show that the optimal initial perturbations of temperature and salinity exciting the strongest decadal THC variations have similar structures: the perturbations are mainly in the northwestern basin at a depth ranging from 1500 to 3000 m. These temperature and salinity perturbations act as the optimal precursors for future modifications of the THC, highlighting the importance of observations in the northwestern basin to monitor the variations of temperature and salinity at depth. The decadal THC variation in the nonlinear model initialized by the optimal salinity perturbations is much stronger than that caused by the optimal temperature perturbations, indicating that salinity variations might play a relatively important role in exciting the decadal THC variability. Moreover, the decadal THC variations in the tangent linear and nonlinear models show remarkably different characteristics, suggesting the importance of nonlinear processes in the decadal variability of the THC.

关键词： thermohaline circulation decadal variability conditional nonlinear optimal perturbation optimal precursor nonlinear processes

Feature of thermohaline circulation in two-layer conceptual model based on energy constraint

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Science China Earth Sciences 2015年第7期58卷 1397-1403页

作者： SHEN Yang GUAN YuPing College of Science Liaoning University of Technology State Key Laboratory of Tropical Oceanography South China Sea Institute of Oceanology Chinese Academy of Sciences

The assertion that the thermohaline circulation(THC)is driven and sustained by mechanical energy has been increasingly *** simplest conceptual model describing the THC is the Stommel two-box *** the vertical stratification in the real ocean,layered models were designed and *** this research,using a two-layer conceptual model based on energy constraint,we studied basic features of thermal-mode and saline-mode *** focused on the effects of freshwater flux and mixing energy on the intensity and multiple equilibrium states of the *** results show that more important than affecting the THC intensity,both the decrease of freshwater flux and increase of mixing energy can lead to an"abrupt transition"in the THC from a stable saline to a stable thermal mode,which further develops the THC energy theory.

关键词： thermohaline circulation two-layer model mixing energy freshwater flux equilibrium state

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Model evidence for climatic impact of thermohaline circulation on China at the century scale

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Science Bulletin 2010年第Z2期 3215-3221页

作者： OTTO-BLIESNER Bette Climate and Global Dynamics Division National Center for Atmospheric Research

Based on transient simulation of the last deglaciation(significant global warming period)using a fully coupled model and sensitivity experiment,we show explicitly how the thermohaline circulation(THC)affects the climate of China,especially during periods of abrupt climate *** simulated evolution of the Chinese climate was consistent with the paleoclimate record during the last *** example,the whole Chinese region warmed significantly during the BФlling-AllerФd warming event(BA).When the magnitude of the THC was reduced in the sensitivity experiment during BA,warming of the Chinese region was greatly *** work shows that in addition to orbital forcing and greenhouse gases,the THC is an important factor influencing climate change in China at the century scale.

关键词： thermohaline circulation China model simulation climate change partial Blocking scheme BФlling-AllerФd warming event Hulu Cave

Sedimentary Characteristics of the Second Marine Layer During the Late Marine Isotope Stage 3 in Southern Yellow Sea and Their Response to the East Asian Monsoon

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Journal of Ocean University of China 2018年第5期17卷 1103-1113页

作者： ZHANG Yang LI Guangxue GUO Hongzhou LIU Yong WANG Haoyin XU Jishang DING Dong QIAO Lulu MA Yanyan WANG Liyan LI Qian College of Marine Geosciences Ocean University of China Key Laboratory of Submarine Geoscience and Prospecting Techniques Ministry of Education Development Research Center China Geological Survey

We use the particle size of sediments in core YS01A to study the sedimentary environment of the mud deposit in the central South Yellow Sea of China during late Marine Isotope Stages 3 （MIS3; 40.5 kyr-31.3 kyr）. In addition, the East Asian Monsoon and its relationship with the North Atlantic Ocean climate change are discussed based on the sensitive grain-size calculation and the spectrum analysis. The results show that during late MIS3, the muddy area in the central South Yellow Sea experienced the evolution of coastal facies, shallow marine facies, coastal facies, and continental facies, with weak hydrodynamic conditions. Compared with other climate indicators, we found that there were many century to millennium-scale climate signals documented in the muddy area sediments in the central South Yellow Sea. According to our particle size results, three strong winter monsoon events occurred at 37.6kyr, 35.6kyr and 32.2kyr. The East Asian Winter Monsoon records in core YS01A are consistent with the Greenland ice core and the Hulu cave stalagmite 8180. The millennial and centennial scale cycles, which are 55 yr, 72 yr, 115 yr, 262 yr respectively, correspond to solar activity cycles, while the 1049 yr and 2941 yr cycles correspond to the Dansgaard-Oeschger cycles. These cycles indicate that the paleoclimate evolution of the area was controlled by the solar activities, with the high-latitude driving thermohaline circulation as the main energy conveyor belt, followed by the sea-air-land amplification of the winter monsoon variation in the central Yellow Sea in the late MIS3.

关键词： sedimentary environment central South Yellow Sea East Asian Monsoon sensitive grade calculation thermohaline circulation

Versions g1.0 and g1.1 of the LASG/IAP Flexible Global Ocean–Atmosphere–Land System Model

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Advances in Atmospheric Sciences 2011年第1期28卷 99-117页

作者：俞永强郑伟鹏王斌刘海龙刘骥平 State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of Sciences

The latest two versions of the IAP Flexible Global Ocean-Atmosphere-Land System （FGOALS） model- versions g1.0 and g1.1, are described in this study. Both two versions are fully coupled GCMs without any flux correction, major changes for g1.1 mainly lie in four aspects：（1） advection schemes for tracer in the ocean component model; （2） zonal filter scheme in high latitudes in the ocean component model; （3） coupling scheme for fresh water flux in high latitudes; and （4） an improved algorithm of airsea turbulent flux depending on the surface current of the ocean. As a result, the substantial cold biases in the tropical Pacific and high latitudes are improved by g1.1, especially g1.1 simulates more reasonable equatorial thermocline, poleward heat transport, zonal overturning stream function in the ocean and sea ice distribution than g1.0. Significant ENSO variability are simulated by both versions, however the ENSO behavior by g1.0 differs from the observed one in many aspects： about twice ENSO amplitude as observed, false ENSO asymmetry, only one peak period around 3 years, etc. Due to improved mean climate state by g1.1, many basic characteristics of ENSO are reproduced by g1.1, e.g., more reasonable ENSO amplitude, two peaks of power spectra for ENSO events, and positive SST skewness in the eastern Pacific as observed.

关键词： air-sea interaction coupled GCM thermohaline circulation ENSO

Effects of astronomical orbital cycle and volcanic activity on organic carbon accumulation during Late Ordovician–Early Silurian in the Upper Yangtze area, South China

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Petroleum Exploration and Development 2021年第4期48卷 850-863页

作者： ZHANG Xi ZHANG Tingshan ZHAO Xiaoming ZHU Haihua MIHAI Emilian Popa CHEN Lei YONG Jinjie XIAO Qiang LI Hongjiao School of Geoscience and Technology Southwest Petroleum UniversityChengdu 610500China Faculty of Geology and Geophysics University of BucharestBucharest 010041Romania

Based on field outcrop data,the effects of cyclic change of astronomical orbit and volcanic activity on organic carbon accumulation during the Late Ordovician-Early Silurian in the Upper Yangtze area were studied using cyclostratigraphic and geochemical methods.d13 C and chemical index of alteration(CIA)were used to filter the astronomical orbit parameters recorded in *** is found that the climate change driven by orbital cycle controls the fluctuations of sea level at different scales,obliquity forcing climate changes drive thermohaline circulation(THC)of the ocean,and THC-induced bottom currents transport nutrient-laden water from high latitude regions to the surface water of low-latitude ***,THC is the main dynamic mechanism of organic-carbon *** marine productivity indexes of Ba/Al and Ni/Al indicate that volcanic activities had limited effect on marine productivity but had great influences on organic carbon preservation efficiency in late Hirnantian(E4).Paleo-ocean redox environmental indicators Th/U,V/Cr and V/(V+Ni)show that there is a significant correlation between volcanism and oxygen content in Paleo-ocean,so it is inferred that volcanisms controlled the organic carbon preservation efficiency by regulating oxygen content in Paleo-ocean,and the difference in volcanism intensity in different areas is an important factor for the differential preservation efficiency of organic *** organic carbon input driven by orbital cycle and the preservation efficiency affected by volcanisms worked together to control the enrichment of organic carbon in the Middle–Upper Yangtze region.

关键词： cyclostratigraphy organic carbon accumulation geochemical weathering index thermohaline circulation volcanic activity Upper Ordovician Wufeng Formation Lower Silurian Longmaxi Formation

Response of IAP/LASG GOALS Model to the Coupling of Air-Sea Fresh Water Exchange

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Advances in Atmospheric Sciences 2000年第3期17卷 473-486页

作者：周天军张学洪俞永强宇如聪刘喜迎金向泽 LASG Institute of Atmospheric Physics Chinese Academy of Sciences

The process of air—sea fresh water exchange is included successfully in the Global— Ocean—Atmosphere Land—System model developed at the State Key Laboratory of Atmospheric Sciences and Geophysical Fluid Dynamics (LASG). The results of the coupled integration show that the climate drift has been controlled successfully. Analyses on the responses of ocean circulation to the changes of surface fresh water or salinity forcing show that the ocean spin-up stage under flux condition for salinity is the key to the implementation of air-sea fresh water flux coupling. This study also demonstrates that the Modified—Monthly—Flux—Anomaly coupling scheme (MMFA) brought forward by Yu and Zhang (1998) is suitable not only for daily air—sea heat flux coupling but also for daily fresh water flux coupling. Key words Fresh water flux - Air-sea coupling - thermohaline circulation This work was co-supported by the National Key Project (Grant No.96-908-02-03), the Excellent National Key Laboratory Research Project (Grant No.49823002) and Chinese Academy of Sciences (CAS) under grant “ Bai Ren Ji Hua? for “Validation of Coupled Climate Models”.

关键词： Fresh water flux Air-sea coupling thermohaline circulation