维普中文期刊产品整合服务
155篇 您的检索式:作者名="Tianjun ZHOU"
    题名 作者 年代 出处 被引量
1Characteristics of decadal-centennial-scale changes in East Asian summer monsoon circulation and precipitation during the Medieval Warm Period and Little Ice Age and in the present day显示文摘Using meteorological observations, proxies of precipitation and temperature, and climate simulation outputs, we synthetically analyzed the regularities of decadal-centennial-scale changes in the summer thermal contrast between land and ocean and summer precipitation over the East Asian monsoon region during the past millennium; compared the basic characteristics of the East Asian summer monsoon (EASM) circulation and precipitation in the present day, the Little Ice Age (LIA) and the Medieval Warm Period (MWP); and explored their links with solar irradiance and global climate change. The results indicate that over the last 150 years, the EASM circulation and precipitation, indicated by the temperature contrast between the East Asian mainland and adjacent oceans, had a significant decadal perturbation and have been weaker during the period of rapid global warming over the past 50 years. On the centennial time scale, the EASM in the MWP was strongest over the past 1000 years. Over the past 1000 years, the EASM was weakest in 1450-1570. When the EASM circulation was weaker, the monsoon rain belt over eastern China was generally located more southward, with there being less precipitation in North China and more precipitation in the Yangtze River valley; therefore, there was an anomalous pattern of southern flood/northern drought. From the 1900s to 1920s, precipitation had a pat- tern opposite to that of the southern flood/northern drought, with there being less precipitation in the Yangtze River valley and more precipitation in North China. Compared with the case for the MWP, there was a longer-time-scale southern flood/northern drought phenomenon in 1400-1600. Moreover, the EASM circulation and precipitation did not synchronously vary with the trend of global temperature. During the last 150 years, although the annual mean surface temperature around the world and in China has increased, the EASM circulation and precipitation did not have strengthening or weakening trends. Over the past 1000 years, the weakest EASM occurred ahead of the lowest Northern Hemispheric temperature and corresponded to the weakest solar irradiance.ZHOU XiuJi ZHAO Ping LIU Ge ZHOU TianJun 2011Chinese Science Bulletin2011,56,28:33
2A comparison of the Medieval Warm Period, Little Ice Age and 20th century warming simulated by the FGOALS climate system model显示文摘To compare differences among the Medieval Warm Period (MWP), Little Ice Age (LIA), and 20th century global warming (20CW), six sets of transient and equilibrium simulations were generated using the climate system model FGOALS_gl. This model was developed by the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences. The results indicate that MWP warming is evident on a global scale, except for at mid-latitudes of the North Pacific. However, the magnitude of the warming is weaker than that in the 20th century. The warming in the high latitudes of the Northern Hemisphere is stronger than that in the Southern Hemisphere. The LIA cooling is also evident on a global scale, with a strong cooling over the high Eurasian continent, while the cooling center is over the Arctic domain. Both the MWP and the 20CW experiments exhibit the strongest warming anomalies in the middle troposphere around 200-300 hPa, but the cooling center of the LIA experiment is seen in the polar surface of the Northern Hemisphere. A comparison of model simulation against the reconstruction indicates that model's performance in simulating the surface air temperature changes during the warm periods is better than that during the cold periods. The consistencies between model and reconstruction in lower latitudes are better than those in high latitudes. Comparison of the inter-annual variability mode of East Asian summer monsoon (EASM) rainfall during the MWP, LIA and 20CW reveals a similar rainfall anomalies pattern. However, the time spectra of the principal component during the three typical periods of the last millennium are different, and the quasi-biannual oscillation is more evident during the two warm periods. At a centennial time scale, the external mode of the EASM variability driven by the changes of effective solar radiation is determined by the changes of large scale land-sea thermal contrast. The rainfall anomalies over the east of 110°E exhibit a meridional homogeneous change pattern, which is different from the meridional out-of-phase change of rainfall anomalies associated with the internal mode.ZHOU TianJun LI Bo MAN WenMin ZHANG LiXia ZHANG Jie 2011Chinese Science Bulletin2011,56,28:32
3The strengthening East Asia summer monsoon since the early 1990s显示文摘Previous studies have documented a weakening tendency of the East Asian summer monsoon (EASM) since the end of the 1970s. In this study, we report that the EASM has been recovering since the early 1990s, although its strength is still less than in previous decades (averaged over the period 1965-1980). Following the recovery of the EASM, there has been a tendency in the last decade toward northward-moving rainbands and excessive rainfall in the Huaihe River valley (110°-120°E, 30°-35°N). There is evidence suggesting that the strengthening EASM since the early 1990s is linked to interdecadal change of land-sea thermal contrast.LIU HaiWen ZHOU TianJun ZHU YuXiang LIN YiHua 2012Chinese Science Bulletin2012,57,13:23
4Theories on Formation of an Anomalous Anticyclone in Western North Pacific during El Nino:A Review显示文摘The western North Pacific anomalous anticyclone(WNPAC) is an important atmospheric circulation system that conveys El Ni?o impact on East Asian climate. In this review paper, various theories on the formation and maintenance of the WNPAC, including warm pool atmosphere–ocean interaction, Indian Ocean capacitor, a combination mode that emphasizes nonlinear interaction between ENSO and annual cycle, moist enthalpy advection/Rossby wave modulation, and central Pacific SST forcing, are discussed. It is concluded that local atmosphere–ocean interaction and moist enthalpy advection/Rossby wave modulation mechanisms are essential for the initial development and maintenance of the WNPAC during El Ni?o mature winter and subsequent spring. The Indian Ocean capacitor mechanism does not contribute to the earlier development but helps maintain the WNPAC in El Ni?o decaying summer.The cold SST anomaly in the western North Pacific, although damped in the summer, also plays a role. An interbasin atmosphere–ocean interaction across the Indo-Pacific warm pool emerges as a new mechanism in summer. In addition, the central Pacific cold SST anomaly may induce the WNPAC during rapid El Ni?o decaying/La Ni?a developing or La Ni?a persisting summer. The near-annual periods predicted by the combination mode theory are hardly detected from observations and thus do not contribute to the formation of the WNPAC. The tropical Atlantic may have a capacitor effect similar to the tropical Indian Ocean.Tim LI Bin WANG Bo WU Tianjun ZHOU Chih-Pei CHANG Renhe ZHANG 2017Journal of Meteorological Research2017,31,6:23
5Comparison of the global air-sea freshwater exchange evaluated from independent datasets显示文摘The implied air-sea freshwater flux is examined in two reanalysis datasets provided respectively by European Center for Medium-range Weather Forecasts and National Center for Environmental Prediction. Not only for annual mean state but also for seasonal variation, two reanalyses agree qualitatively well with each other, and both can reproduce reasonably the global distribution of E-P (i.e. Evaporation minus Precipitation). In the view of quantitative comparison, however, remarkable difference has been found on regional scales, especially over the middle and lower latitudes, with some local disagreement exceeding 100 cm/yr. One important difference between current and previous evaluation is the new found net evaporation over the high latitude North Atlantic, which is demonstrated to result from the transient disturbances during boreal winter.ZHOU Tianjun(State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China) 2003Progress in Natural Science:Materials International2003,13,8:21
6Climate sensitivities of two versions of FGOALS model to idealized radiative forcing显示文摘Projections of future climate change by climate system models depend on the sensitivities of models to specified greenhouse gases.To reveal and understand the different climate sensitivities of two versions of LASG/IAP climate system model FGOALS-g2 and FGOALS-s2,we investigate the global mean surface air temperature responses to idealized CO2 forcing by using the output of abruptly quadrupling CO2 experiments.The Gregory-style regression method is used to estimate the'radiative forcing'of quadrupled CO2 and equilibrium sensitivity.The model response is separated into a fast-response stage associated with the CO2 forcing during the first 20 years,and a slow-response stage post the first 20 years.The results show that the radiative forcing of CO2 is overestimated due to the positive water-vapor feedback and underestimated due to the fast cloud processes.The rapid response of water vapor in FGOALS-s2 is responsible for the stronger radiative forcing of CO2.The climate sensitivity,defined as the equilibrium temperature change under doubled CO2 forcing,is about 3.7 K in FGOALS-g2 and4.5 K in FGOALS-s2.The larger sensitivity of FGOALS-s2 is due mainly to the weaker negative longwave clear-sky feedback and stronger positive shortwave clear-sky feedback at the fast-response stage,because of the more rapid response of water vapor increase and sea-ice decrease in FGOALS-s2 than in FGOALS-g2.At the slow-response stage,similar to the fast-response stage,net negative clear-sky feedback is weaker in FGOALS-s2.Nevertheless,the total negative feedback is larger in FGOALS-s2 due to a larger negative shortwave cloud feedback that involves a larger response of total cloud fraction and condensed water path increase.The uncertainties of estimated forcing and net feedback mainly come from the shortwave cloud processes.CHEN XiaoLong ZHOU TianJun GUO Zhun 2014Science China Earth Sciences2014,57,6:19
7Forced response of atmospheric oscillations during the last millennium simulated by a climate system model显示文摘Variations in global atmospheric oscillations during the last millennium are simulated using the climate system model FGOALS_gl. The model was driven by reconstructions of both natural forcing (solar variability and volcanic aerosol) and anthropogenic forcing (greenhouse gases and sulfate aerosol). The model results are compared against proxy reconstruction data. The reconstructed North Atlantic Oscillation (NAO) was out of phase with the Pacific Decadal Oscillation (PDO) in the last millennium. During the Medieval Warm Period (MWP), the NAO was strong while the PDO was weak. During the Little Ice Age (LIA), the NAO was weak while the PDO was strong. A La Ni a-like state prevailed in the MWP, while an El Ni o-like state dominated in the LIA. This phenomenon is particularly obvious in the 15th, 17th and 19th centuries. Analysis of the model output indicates that the NAO was generally positive during 1000-1400 AD and negative during 1650-1900 AD. There is a discrepancy between the sim- ulation and reconstruction during 1400-1650 AD. The simulated PDO generally varies in parallel with the reconstruction, which has a negative phase during the MWP and a positive phase during the LIA. The correlation coefficient between the reconstruction and simulation is 0.61, and the correlation is statistically significant at the 1% level. Neither the La Ni a-like state of the MWP nor the El Ni o-like state of the LIA is reproduced in the model. Both the reconstructed and the simulated Antarctic Oscillations had a negative phase in the early period of the last millennium and a positive phase in the late period of the last millennium. The Asian-Pacific Oscillation was generally strong during the WMP and weak during the LIA, and the correlation coefficient between the simulation and reconstruction is 0.50 for the period 1000 -1985 AD. The analysis suggests that the specified external forcings significantly affected the evolution of atmospheric oscillation during the last millennium.MAN WenMin ZHOU TianJun 2011Chinese Science Bulletin2011,56,28:18
8Advances in studying interactions between aerosols and monsoon in China显示文摘Scientific issues relevant to interactions between aerosols and the Asian monsoon climate were discussed and evaluated at the 33 rd 'Forum of Science and Technology Frontiers' sponsored by the Department of Earth Sciences at the Chinese Academy of Sciences. Major results are summarized in this paper. The East Asian monsoon directly affects aerosol transport and provides a favorable background circulation for the occurrence and development of persistent fog-haze weather. Spatial features of aerosol transport and distribution are also influenced by the East Asian monsoon on seasonal, inter-annual, and decadal scales. High moisture levels in monsoon regions also affect aerosol optical and radiative properties. Observation analyses indicate that cloud physical properties and precipitation are significantly affected by aerosols in China with aerosols likely suppressing local light and moderate rainfall, and intensifying heavy rainfall in southeast coastal regions. However, the detailed mechanisms behind this pattern still need further exploration. The decadal variation in the East Asian monsoon strongly affects aerosol concentrations and their spatial patterns. The weakening monsoon circulation in recent decades has likely helped to increase regional aerosol concentrations. The substantial increase in Chinese air pollutants has likely decreased the temperature difference between land and sea, which favors intensification of the weakening monsoon circulation. Constructive suggestions regarding future studies on aerosols and monsoons were proposed in this forum and key uncertain issues were also discussed.WU GuoXiong LI ZhanQing FU CongBin ZHANG XiaoYe ZHANG RenYi ZHANG RenHe ZHOU TianJun LI JianPing LI JianDong ZHOU DeGang WU Liang ZHOU LianTong HE Bian HUANG RongHui 2016Science China Earth Sciences2016,59,1:16
9Human umbilical cord-derived mesenchymal stem cell therapy in patients with COVID-19:a phase 1 clinical trial显示文摘No effective drug treatments are available for coronavirus disease 2019(COVID-19).Host-directed therapies targeting the underlying aberrant immune responses leading to pulmonary tissue damage,death,or long-term functional disability in survivors require clinical evaluation.We performed a parallel assigned controlled,non-randomized,phase 1 clinical trial to evaluate the safety of human umbilical cord-derived mesenchymal stem cells(UC-MSCs)infusions in the treatment of patients with moderate and severe COVID-19 pulmonary disease.The study enrolled 18 hospitalized patients with COVID-19(n=9 for each group).The treatment group received three cycles of intravenous infusion of UC-MSCs(3×107 cells per infusion)on days 0,3,and 6.Both groups received standard COVID-treatment regimens.Adverse events,duration of clinical symptoms,laboratory parameters,length of hospitalization,serial chest computed tomography(CT)images,the PaO2/FiO2 ratio,dynamics of cytokines,and IgG and IgM anti-SARS-CoV-2 antibodies were analyzed.No serious UC-MSCs infusion-associated adverse events were observed.Two patients receiving UC-MSCs developed transient facial flushing and fever,and one patient developed transient hypoxia at 12 h post UC-MSCs transfusion.Mechanical ventilation was required in one patient in the treatment group compared with four in the control group.All patients recovered and were discharged.Our data show that intravenous UC-MSCs infusion in patients with moderate and severe COVID-19 is safe and well tolerated.Phase 2/3 randomized,controlled,double-blinded trials with long-term follow-up are needed to evaluate the therapeutic use of UC-MSCs to reduce deaths and improve long-term treatment outcomes in patients with serious COVID-19.Fanping Meng Ruonan Xu Siyu Wang Zhe Xu Chao Zhang Yuanyuan Li Tao Yang Lei Shi Junliang Fu Tianjun Jiang Lei Huang Peng Zhao Xin Yuan Xing Fan Ji-Yuan Zhang Jinwen Song Dawei Zhang Yanmei Jiao Limin Liu Chunbao Zhou Markus Maeurer Alimuddin Zumla Ming Shi Fu-Sheng Wang 2020Signal Transduction and Targeted Therapy2020,5,1:16
10Impact of 1.5°C and 2.0°C global warming on aircraft takeoff performance in China显示文摘Associated with global warming, climate extremes such as extreme temperature will significantly increase. Understanding how climate change will impact the airflights is important to the planning of future flight operations. In this study, the impacts of 1.5 and 2 degree's global warming on the aircraft takeoff performance in China are investigated using a unique climate projection data from an international collaboration project named HAPPI. It is found that the mean summer daily maximum temperature, which is a major factor that affects the flight through changing the aircraft's takeoff weight, will increase significantly with magnitude less than 1.5℃ over most parts of China except for the Tibetan Plateau. The half a degree additional global warming will lead to higher extreme temperature in the arid and semi-arid western China, the Tibetan Plateau and the northeastern China, while the change in eastern China is weak. Five airports including Beijing, Shanghai, Kunming, Lasa and Urumqi will see ~1.0°-2.0℃(1.4°-3.0℃) higher daily maximum temperature under 1.5℃(2.0℃) scenario. The half-degree additional warming will lead to a shift toward higher extreme temperature in these five sites. For both1.5° and 2.0℃ scenarios, the number of weight-restriction days will increase significantly at 3 airports including Beijing, Shanghai, and Lasa. Urumqi will witness an increase of weight-restriction days only in 2.0℃ future.Tianjun Zhou Liwen Ren Haiwen Liu Jingwen Lu 2018Science Bulletin2018,63,11:16
11The CAMS Climate System Model and a Basic Evaluation of Its Climatology and Climate Variability Simulation显示文摘A new coupled climate system model(CSM) has been developed at the Chinese Academy of Meteorological Sciences(CAMS) by employing several state-of-the-art component models. The coupled CAMS-CSM consists of the modified atmospheric model [ECmwf-HAMburg(ECHAM5)], ocean model [Modular Ocean Model(MOM4)], sea ice model [Sea Ice Simulator(SIS)], and land surface model [Common Land Model(CoLM)]. A detailed model description is presented and both the pre-industrial and 'historical' simulations are preliminarily evaluated in this study.The model can reproduce the climatological mean states and seasonal cycles of the major climate system quantities,including the sea surface temperature, precipitation, sea ice extent, and the equatorial thermocline. The major climate variability modes are also reasonably captured by the CAMS-CSM, such as the Madden–Julian Oscillation(MJO), El Ni?o–Southern Oscillation(ENSO), East Asian Summer Monsoon(EASM), and Pacific Decadal Oscillation(PDO).The model shows a promising ability to simulate the EASM variability and the ENSO–EASM relationship. Some biases still exist, such as the false double-intertropical convergence zone(ITCZ) in the annual mean precipitation field,the overestimated ENSO amplitude, and the weakened Bjerknes feedback associated with ENSO; and thus the CAMS-CSM needs further improvements.Xinyao RONG Jian LI Haoming CHEN Yufei XIN Jingzhi SU Lijuan HUA Tianjun ZHOU Yanjun QI Zhengqiu ZHANG Guo ZHANG Jianduo LI 2018Journal of Meteorological Research2018,32,6:15
12Uncertainty in crossing time of 2 °C warming threshold over China显示文摘The 2 °C warming target has been used widely in global and regional climate change research. Previous studies have shown large uncertainties in the time when surface air temperature(SAT) change over China will reach 2 °C relative to the pre-industrial era. To understand the uncertainties,we analyzed the projected SAT in the twenty-first century using 40 state-of-the-art climate models under two Representative Concentration Pathways(RCP4.5 and RCP8.5)from the Coupled Model Intercomparison Project Phase 5.The 2 °C threshold-crossing time(TCT) of SAT averaged across China was around 2033 and 2029 for RCP4.5 and RCP8.5, respectively. Considering a ±1r range of intermodel SAT change, the upper and lower bounds of the 2 °C TCT could differ by about 25 years or even more. Uncertainty in the projected SAT and the warming rate around the TCT are the two main factors responsible for the TCT uncertainty. The former is determined by the climate sensitivity represented by the global mean surface temperature response. About 45 % of the intermodel variance of the projected 2 °C TCT for averaged SAT over China can be explained by climate sensitivity across the models, which is contributed mainly by central and southern China. In a climate more sensitive to CO2 forcing, stronger greenhouse effect, less stratus cloud over the East Asian monsoon region,and less snow cover on the Tibetan Plateau result in increased downward longwave radiation, increased shortwave radiation, and decreased shortwave radiation reflected by the surface, respectively, all of which may advance the TCT.Xiaolong Chen Tianjun Zhou 2016Science Bulletin2016,61,18:15
13An Assessment of Improvements in Global Monsoon Precipitation Simulation in FGOALS-s2显示文摘The performance of Version 2 of the Flexible Global Ocean–Atmosphere–Land System model(FGOALS-s2) in simulating global monsoon precipitation(GMP) was evaluated. Compared with FGOALS-s1, higher skill in simulating the annual modes of climatological tropical precipitation and interannual variations of GMP are seen in FGOALS-s2. The simulated domains of the northwestern Pacific monsoon(NWPM) and North American monsoon are smaller than in FGOALS-s1. The main deficiency of FGOALS-s2 is that the NWPM has a weaker monsoon mode and stronger negative pattern in spring–fall asymmetric mode. The smaller NWPM domain in FGOALS-s2 is due to its simulated colder SST over the western Pacific warm pool. The relationship between ENSO and GMP is simulated reasonably by FGOALS-s2. However, the simulated precipitation anomaly over the South African monsoon region–South Indian Ocean during La Nin a years is opposite to the observation. This results mainly from weaker warm SST anomaly over the maritime continent during La Nin a years, leading to stronger upper-troposphere(lower-troposphere) divergence(convergence) over the Indian Ocean, and artificial vertical ascent(descent) over the Southwest Indian Ocean(South African monsoon region), inducing local excessive(deficient) rainfall. Comparison between the historical and pre-industrial simulations indicated that global land monsoon precipitation changes from 1901 to the 1970s were caused by internal variation of climate system. External forcing may have contributed to the increasing trend of the Australian monsoon since the 1980s. Finally, it shows that global warming could enhance GMP, especially over the northern hemispheric ocean monsoon and southern hemispheric land monsoon.ZHANG Lixia ZHOU Tianjun 2014Advances in Atmospheric Sciences2014,31,1:14
14The relationship between the thermohaline circulation and climate variability显示文摘The long-term integration with the Global Ocean-Atmosphere-Land System model of the State Key Laboratory of Atmospheric Sciences and Geophysical Fluid Dynamics (LASG), Institute of Atmospheric Physics(IAP), Chinese Academy of Sciences has been used in the investigations on the relationship between the thermohaline circulation and climate variability. The results show that the strength of the North Atlantic Thermohaline circulation (THC) is negatively correlated with the North Atlantic Oscillation (NAO). Based on this kind of relationship, and also the instrument-measured climate record such as air pressure and sea surface temperature, the activity of the thermohaline circulation during the 20th century has been evaluated. The inferred variations of the strength of the THC is that, during two multi-decadal periods of 1867-1903 and 1934-1972, the THC is estimated to have been running stronger, whereas during the two periods of 1904-1933 and 1973-1994, it appears to have been weaker.ZHOU Tianjun ZHANG Xuehong WANG Shaowu 2000Chinese Science Bulletin2000,45,11:13
15Regional-scale Surface Air Temperature and East Asian Summer Monsoon Changes during the Last Millennium Simulated by the FGOALS-gl Climate System Model显示文摘The spatial patterns and regional-scale surface air temperature(SAT) changes during the last millennium, as well as the variability of the East Asian summer monsoon(EASM) were simulated with a low-resolution version of Flexible Global Ocean–Atmosphere–Land–Sea-ice(FGOALS-gl) model. The model was driven by both natural and anthropogenic forcing agents. Major features of the simulated past millennial Northern Hemisphere(NH) mean SAT variations, including the Medieval Climate Anomaly(MCA), the Little Ice Age(LIA) and the 20th Century Warming(20CW), were generally consistent with the reconstructions. The simulated MCA showed a global cooling pattern with reference to the 1961–90 mean conditions, indicating the 20CW to be unprecedented over the last millennium in the simulation. The LIA was characterized by pronounced coldness over the continental extratropical NH in both the reconstruction and the simulation. The simulated global mean SAT difference between the MCA and LIA was 0.14°C, with enhanced warming over high-latitude NH continental regions. Consistencies between the simulation and the reconstruction on regional scales were lower than those on hemispheric scales. The major features agreed well between the simulated and reconstructed SAT variations over the Chinese domain, despite some inconsistency in details among different reconstructions. The EASM circulation during the MCA was stronger than that during the LIA The corresponding rainfall anomalies exhibited excessive rainfall in the north but deficient rainfall in the south. Both the zonal and meridional thermal contrast were enhanced during the MCA. This temperature anomaly pattern favored a stronger monsoon circulation.MAN Wenmin ZHOU Tianjun 2014Advances in Atmospheric Sciences2014,31,4:12
16Impacts of external forcing on the 20th century global warming显示文摘The impacts of external forcing,including natural and anthropogenic,on the 20th century global warming were assessed with the use of the Grid Atmospheric Model of IAP/LASG Version 1.1.0,fol-lowing the standard coordinated experiment design of the Climate Variability and Predictability(CLIVAR) International Climate of the Twentieth Century Project(C20C) ,Phase II. The results indicate that external forcing plays an important role in the evolution of the land surface air temperature on in-terannual,decadal,and interdecadal time scales,and contributes greatly to the global warming in the following two periods:the early twentieth century between the 1910s and the 1940s and the late twen-tieth century after the 1970s. External forcing also has strong impact on the regional temperature change during the two warming periods except for parts of the Eurasia and the North America conti-nents. In the cooling period,however,the impact of internal variability is dominant.LI LiJuan WANG Bin ZHOU TianJun 2007Chinese Science Bulletin2007,52,22:12
17Paleoclimate Modeling in China: A Review显示文摘This paper provides a review of paleoclimate modeling activities in China. Rather than attempt to cover all topics, we have chosen a few climatic intervals and events judged to be particularly informative to the international community. In historical climate simulations, changes in solar radiation and volcanic activity explain most parts of reconstructions over the last millennium prior to the industrial era, while atmospheric greenhouse gas concentrations play the most important role in the20 th century warming over China. There is a considerable model–data mismatch in the annual and boreal winter temperature change over China during the mid-Holocene [6000 years before present(ka BP)], while coupled models with an interactive ocean generally perform better than atmospheric models. For the Last Glacial Maximum(21 ka BP), climate models successfully reproduce the surface cooling trend over China but fail to reproduce its magnitude, with a better performance for coupled models. At that time, reconstructed vegetation and western Pacific sea surface temperatures could have significantly affected the East Asian climate, and environmental conditions on the Qinghai–Tibetan Plateau were most likely very different to the present day. During the late Marine Isotope Stage 3(30–40 ka BP), orbital forcing and Northern Hemisphere glaciation, as well as vegetation change in China, were likely responsible for East Asian climate change. On the tectonic scale,the Qinghai–Tibetan Plateau uplift, the Tethys Sea retreat, and the South China Sea expansion played important roles in the formation of the East Asian monsoon-dominant environment pattern during the late Cenozoic.JIANG Dabang YU Ge ZHAO Ping CHEN Xing LIU Jian LIU Xiaodong WANG Shaowu ZHANG Zhongshi YU Yongqiang LI Yuefeng JIN Liya XU Ying JU Lixia ZHOU Tianjun YAN Xiaodong 2015Advances in Atmospheric Sciences2015,32,2:12
18An improved diagnostic stratocumulus scheme based on estimated inversion strength and its performance in GAMIL2显示文摘Based on satellite data and the estimated inversion strength(EIS) derived by Wood et al.(2006), a feasible and uncomplicated stratocumulus scheme is proposed, referred to as EIS scheme. It improves simulation of cloud radiative forcing(CRF) in the Grid-point Atmospheric Model of IAP/LASG version 2(GAMIL2.0) model. When compared with the original lower troposphere stability(LTS) scheme, the EIS scheme reproduces more reasonable climatology distributions of clouds and CRF. The parameterization partly corrects CRF underestimation at mid and high latitudes and overestimation in the convective region. Such improvements are achieved by neglecting the effect of free-tropospheric stratification changes that follow a cooler moist adiabat at middle and high latitude, thereby improving simulated cloudiness. The EIS scheme also improves simulation of the CRF interannual variability. The positive net CRF and negative stratiform anomaly in the East Asian and western North Pacific monsoon regions(EAWNPMR) are well simulated. The EIS scheme is more sensitive to sea surface temperature anomalies(SSTA) than the LTS. Therefore, under the effect of a warmer SSTA in the EAWNPMR, the EIS generates a stronger negative stratiform response, which reduces radiative heating in the low and mid troposphere, in turn producing strong subsidence and negative anomalies of both moisture and cloudiness. Consequent decreases in cloud reflection and shading effects ultimately improve simulation of incoming surface shortwave radiative fluxes and CRF. Because of the stronger subsidence, a stronger anomalous anticyclone over the Philippines Sea is simulated by the EIS run, which leads to a better positive precipitation anomaly in eastern China during ENSO winter.GUO Zhun ZHOU TianJun 2014Science China Earth Sciences2014,57,11:11
19Climate Sensitivity and Feedbacks of a New Coupled Model CAMS-CSM to Idealized CO_2 Forcing: A Comparison with CMIP5 Models显示文摘Climate sensitivity and feedbacks are basic and important metrics to a climate system. They determine how large surface air temperature will increase under CO_2 forcing ultimately, which is essential for carbon reduction policies to achieve a specific warming target. In this study, these metrics are analyzed in a climate system model newly developed by the Chinese Academy of Meteorological Sciences(CAMS-CSM) and compared with multi-model results from the Coupled Model Comparison Project phase 5(CMIP5). Based on two idealized CO_2 forcing scenarios, i.e.,abruptly quadrupled CO_2 and CO_2 increasing 1% per year, the equilibrium climate sensitivity(ECS) and transient climate response(TCR) in CAMS-CSM are estimated to be about 2.27 and 1.88 K, respectively. The ECS is near the lower bound of CMIP5 models whereas the TCR is closer to the multi-model ensemble mean(MME) of CMIP5 due to compensation of a relatively low ocean heat uptake(OHU) efficiency. The low ECS is caused by an unusually negative climate feedback in CAMS-CSM, which is attributed to cloud shortwave feedback(λSWCL) over the tropical Indo-Pacific Ocean.The CMIP5 ensemble shows that more negative λSWCL is related to larger increase in low-level(925–700 hPa)cloud over the tropical Indo-Pacific under warming, which can explain about 90% of λSWCL in CAMS-CSM. Static stability of planetary boundary layer in the pre-industrial simulation is a critical factor controlling the low-cloud response and λSWCL across the CMIP5 models and CAMS-CSM. Evidently, weak stability in CAMS-CSM favors lowcloud formation under warming due to increased low-level convergence and relative humidity, with the help of enhanced evaporation from the warming tropical Pacific. Consequently, cloud liquid water increases, amplifying cloud albedo, and eventually contributing to the unusually negative λSWCL and low ECS in CAMS-CSM. Moreover, the OHU may influence climate feedbacks and then the ECS by modulating regional sea surface temperature responses.Xiaolong CHEN Zhun GUO Tianjun ZHOU Jian LI Xinyao RONG Yufei XIN Haoming CHEN Jingzhi SU 2019Journal of Meteorological Research2019,33,1:11
20The Asian Subtropical Westerly Jet Stream in CRA-40, ERA5, and CFSR Reanalysis Data:Comparative Assessment显示文摘The Asian subtropical westerly jet(AWJ) exerts crucial influences on Eurasian continent weather and climate. This paper analyzes the advantages and limitations of CRA-40, which is China's first generation 40-yr(1979–2018) global atmosphere and land reanalysis product, in describing the characteristics of AWJ, compared with the ECMWF Reanalysis version 5(ERA5) and NCEP Climate Forecast System Reanalysis(CFSR). The results show a close agreement across the three reanalyses on the whole.(1) In terms of climatology, overall differences of 200-h Pa zonal wind across the three reanalyses are within ± 0.5 m s^(-1)(i.e., ± 2%). Large differences with maxima of ± 2 m s^(-1)(±5%) appear over the Iranian Plateau and south of the Tibetan Plateau in the mid–upper troposphere in winter.(2) For seasonal cycle, the position and intensity of the AWJ centers in the three reanalyses are highly consistent, with correlation coefficient over 0.98. But there are some discrepancies in the zonal shift of the western AWJ center during the transition season.(3) On the interannual timescale, intensity of all AWJ centers varies consistently among the three reanalyses, while larger differences appear in their meridional displacement, especially in the eastern AWJ center.(4)For long-term variations, the three reanalyses all present a significant northward movement of the westerly jet axis in winter, and a southward displacement over central Asia(40°–80°E) and a northward migration over East Asia(80°–110°E) in summer. Thus, this study has provided confidence that CRA-40 has comparable performance with ERA5 and CFSR in depicting the characteristics of AWJ.Xiaojing YU Lixia ZHANG Tianjun ZHOU Jingwei LIU 2021Journal of Meteorological Research2021,35,1:10
返回顶部 每页显示:
共8页 首页 上一页 第1页 下一页 末页 /8 跳转

网站首页 | 关于我们 | 联系我们 | 产品服务 | 客服中心 | 广告服务 | 版权声明 | 网站联盟 | 友情链接 | 售卡网点

版权所有© 渝B2-20050021-1 渝公网安备 50019002500403号 违法和不良信息举报中心

互联网出版许可证 新出网证(渝)字10号 全国400电话 - 免长途话费