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Evaluation and Analysis of RegCM3 Simulated Summer Rainfall over the Huaihe River Basin of China

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Acta meteorologica Sinica 2011年第3期25卷 386-394页

作者：宗培书王会军 nansen-zhu international research centre Institute of Atmospheric PhysicsChinese Academy of Sciences Graduate University of Chinese Academy of Sciences

This study evaluates the ability of the Abdus Salam international Center for Theoretical Physics （ICTP） version 3 Regional Climate Model （RegCM3） in simulating the summer rainfall amount and distribution and large-scale circulation over the Huaihe River basin of China. We conducted the simulation for the period of 1982-2001 and the wet year of 2003 to test the ensemble simulation capacity of RegCM3. First, by comparing the simulated rainfall amount and distribution against the observations, it is found that RegCM3 can reproduce the rainfall pattern and its annual variations. In addition, the simulated spatial patterns of 850-hPa wind and specific humidity fields are close to the observations, although the wind speed and humidity values are larger. Finally, the ensemble simulation of RegCM3 for summer 2003 failed to capture the spatial distribution and underestimated the magnitude of the precipitation anomalies, and the reasons are analyzed.

关键词： regional climate model the Huaihe River basin precipitation ensemble simulation

The Response of the East Asian Summer Monsoon to Strong Tropical Volcanic Eruptions

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Advances in Atmospheric Sciences 2014年第6期31卷 1245-1255页

作者： CUI Xuedong GAO Yongqi SUN Jianqi nansen-zhu international research centre Institute of Atmospheric PhysicsChinese Academy of Sciences University of Chinese Academy of Sciences nansen Environmental and Remote Sensing Center Bergen Bjerknes Center for Climate research University of Bergen

A 600-year integration performed with the Bergen Climate Model and National Centers for Environmental Prediction/National Center for Atmospheric research （NCEP/NCAR） reanalysis data were used to investigate the impact of strong tropical volcanic eruptions on the East Asian summer monsoon （EASM） and EASM *** the simulation and NCEP/NCAR reanalysis data show a weakening of the EASM in strong eruption *** model simulation suggests that North and South China experience droughts and the Yangtze-Huaihe River Valley experiences floods during eruption *** response to strong tropical volcanic eruptions,the meridional air temperature gradient in the upper troposphere is enhanced,which leads to a southward shift and an increase of the East Asian subtropical westerly jet stream （EASWJ）.At the same time,the land-sea thermal contrast between the Asian land mass and Northwest Pacific Ocean is *** southward shift and increase of the EASWJ and reduction of the land-sea thermal contrast all contribute to a weakening of the EASM and EASM rainfall anomaly.

关键词： East Asian summer monsoon volcanic eruption East Asian subtropical westerly jet stream land-sea thermal contrast

Evaluation of Routed-Runoff from Land Surface Models and Reanalyses Using Observed Streamflow in Chinese River Basins

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Journal of Meteorological research 2020年第1期34卷 73-87页

作者： Yue MIAO Aihui WANG nansen–zhu international research centre Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029 University of Chinese Academy of Sciences Beijing 100049

Previous studies have demonstrated that offline land surface models(LSMs)and global hydrological models(GHMs)can reasonably reproduce streamflow in large river *** reanalyses supply fine spatiotemporal runoff estimates,but they are not fully intercompared and evaluated in *** study assesses the routed-runoff from five offline LSM/GHM runs(VIC-CN05.1,CLM-CFSR,CLM-ERAI,CLM-MERRA,and CLM-NCEP)and three reanalysis datasets(ERAI/Land,JRA55,and MERRA-2)against the gauged streamflow(26 stations)in major Chinese river basins during 1980–*** Catchment-based Macro-scale Floodplain model(CaMa-Flood)is employed to route those runoff datasets to the hydrological *** statistical quantities,including the correlation coefficient(R),standard deviation(STD),Nash–Sutcliffe efficiency coefficient(NSE),and relative error(RE),along with a ranking method,are used to quantify the quality of those *** results show that the spatial patterns of both modeled and observed streamflow in summer are similar,but their magnitudes are *** for MERRA-2,the other products can reproduce well the interannual variability of streamflow in both the Yangtze and Yellow River *** products generally underestimate the magnitude and variance of monthly streamflow,while VIC-CN05.1 and JRA55 are closer to observations compared to other *** correlation coefficients for all products are overall larger than 0.61,with the highest value(0.85)from *** addition to CLM-MERRA,MERRA-2,and CLM-NCEP with relatively small precipitation,other products can simulate peak flow well with positive NSEs up to 0.41(ERAI/Land).Considerable uncertainties exist among the eight products at the Yellow River outlet,which might be because the LSMs ignore frequent human *** on the above statistics,performances of the eight runoff products are ranked in descending order as follows:VIC-CN05.1,ERAI/Land,JRA55,CLM-CFSR,CLM-ERAI,MERRA-2,CLM-MERRA,and CLM-NCE

关键词： runoff land surface model(LSM) reanalysis data Catchment-based Macro-scale Floodplain model(CaMa-Flood) observed streamflow

A Comparison of Polar Vortex Response to Pacific and Indian Ocean Warming

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Advances in Atmospheric Sciences 2010年第3期27卷 469-482页

作者：李双林 nansen-zhu international research centre Institute of Atmospheric PhysicsChinese Academy of Sciences Climate Change research Center Chinese Academy of Sciences

During recent decades, the tropical Indo-Pacific Ocean has become increasingly warmer. Meanwhile, both the northern and southern hemispheric polar vortices （NPV and SPV） have exhibited a deepening trend in boreal winter. Although previous studies have revealed that the tropical Indian Ocean warming （IOW） favors an intensifying NPV and a weakening SPV, how the tropical Pacific Ocean warming （POW） influences the NPV and SPV remains unclear. In this study, a comparative analysis has been conducted through ensemble atmospheric general circulation model （AGCM） experiments. The results show that, for the Northern Hemisphere, the two warmings exerted opposite impacts in boreal winter, in that the IOW intensified the NPV while the POW weakened the NPV. For the Southern Hemisphere, both the IOW and POW warmed the southern polar atmosphere and weakened the SPV. A diagnostic analysis based on the vorticity budget revealed that such an interhemispheric difference in influences from the IOW and POW in boreal winter was associated with different roles of transient eddy momentum flux convergence between the hemispheres. Furthermore, this difference may have been linked to different strengths of stationary wave activity between the hemispheres in boreal winter.

关键词： tropical Indo-Pacific Ocean warming northern and southern polar vortex atmospheric generalcirculation model transient eddy stationary wave

Skewness of subsurface ocean temperature in the equatorial Pacific based on assimilated data

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Chinese Journal of Oceanology and Limnology 2009年第3期27卷 600-606页

作者：苏京志张人禾 LI Tim 容新尧 Chinese Academy of Meteorological Sciences nansen-zhu international research centre Institute of Atmospheric PhysicsChinese Academy of Sciences international Pacific research Center and Department of Meteorology University of Hawaii at Manoa

The skewness of subsurface temperature anomaly in the equatorial Pacific Ocean shows a significant asymmetry between the east and west. A positive temperature skewness appears in the equatorial eastern Pacific, while the temperature skewness in the western and central Pacific is primarily negative. There is also an asymmetry of the temperature skewness above and below the climatological mean therrnocline in the central and western Pacific. A positive skewness appears below the thermocline, but the skewness is negative above the thermocline. The distinctive vertical asymmetry of the temperature skewness is argued to be attributed to the asymmetric temperature response to upward and downward thermocline displacement in the presence of the observed upper-ocean vertical thermal structure. Because of positive （negative） second derivative of temperature with respect to depth below （above） the thermocline, an upward and a downward shift of the thermocline with equal displacement would lead to a negative temperature skewness above the thermocline but a positive skewness below the thermocline. In the far eastern equatorial Pacific, the thermocline is close to the base of the mixed layer, the shape of the upper-ocean vertical temperature profile cannot be kept. Positive skewness appears in both below the thermocline and above the thermocline in the far eastern basin. Over the central and eastern Pacific, the anomalies of the subsurface waters tend to entrain into the surface mixed layer （by climatological mean upwelling） and then affect the SST. Hence, the positive （negative） subsurface skewness in the far eastern （central） Pacific may favor positive （negative） SST skewness, which is consistent with the observational fact that more La Nina （EI Nino） occur in the central （eastern） Pacific. The present result implies a possible new paradigm for EI Nino and La Nina amplitude asymmetry in the eastern Pacific.

关键词： skewness subsurface temperature equatorial ocean

Assessment of Temperature Extremes in China Using RegCM4 and WRF

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Advances in Atmospheric Sciences 2019年第4期36卷 363-377页

作者： Xianghui KONG Aihui WANG Xunqiang BI Dan WANG nansen-zhu international research centre Institute of Atmospheric PhysicsChinese Academy of Sciences Climate Change research Center Institute of Atmospheric PhysicsChinese Academy of Sciences

This study assesses the performance of temperature extremes over China in two regional climate models(RCMs),RegCM4 and WRF, driven by the ECMWF's 20 th century reanalysis. Based on the advice of the Expert Team on Climate Change Detection and Indices(ETCCDI), 12 extreme temperature indices(i.e., TXx, TXn, TNx, TNn, TX90 p, TN90 p,TX10 p, TN10 p WSDI, ID, FD, and CSDI) are derived from the simulations of two RCMs and compared with those from the daily station-based observational data for the period 1981–2010. Overall, the two RCMs demonstrate satisfactory capability in representing the spatiotemporal distribution of the extreme indices over most regions. RegCM performs better than WRF in reproducing the mean temperature extremes, especially over the Tibetan Plateau(TP). Moreover, both models capture well the decreasing trends in ID, FD, CSDI, TX10 p, and TN10 p, and the increasing trends in TXx, TXn, TNx, TNn, WSDI, TX90 p,and TN90 p, over China. Compared with observation, RegCM tends to underestimate the trends of temperature extremes,while WRF tends to overestimate them over the TP. For instance, the linear trends of TXx over the TP from observation,RegCM, and WRF are 0.53?C(10 yr)^(-1), 0.44?C(10 yr)^(-1), and 0.75?C(10 yr)^(-1), respectively. However, WRF performs better than RegCM in reproducing the interannual variability of the extreme-temperature indices. Our findings are helpful towards improving our understanding of the physical realism of RCMs in terms of different time scales, thus enabling us in future work to address the sources of model biases.

关键词： dynamical downscaling extreme-temperature index observation RegCM WRF

Unprecedented Retreat in a 50-Year Observational Record for Petermann Glacier, North Greenland

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Atmospheric and Oceanic Science Letters 2013年第5期6卷 259-265页

作者： Ola M. JOHANNESSEN Mohamed BABIKER Martin W. MILES nansen Environmental and Remote Sensing Center nansen Scientific Society nansen-zhu international research Center Institute of Atmospheric Physics Chinese Academy of Sciences Uni research AS Bjerknes centre for Climate research

Petermann Glacier is a marine-terminating outlet glacier that had a 70 km-long floating ice tongue prior to a ～ 270 km2 calving event that was observed from satellite sensors in August 2010,shortening the ice tongue by ～ 27 ***,in July 2012,another 10 km was lost through *** order to understand these events in perspective,here the authors perform a long-term data analysis of Petermann Glacier calving-front variability and ice velocity for each year in the 1990s-2000s,supplemented by available observations from the previous three *** major （on the order of 100 krm2） calving events are identified,with ～ 153 km2 calved from 1959 to 1961,～ 168 km2 in 1991,～ 71 km2 in 2001,～ 270 km2 in 2010,and ～ 130 km2 in 2012-as well as ～ 31 k m2 calved in *** increased frequency of major calving events in recent years has left the front terminus position retreated nearly 25 km beyond the range of observed in previous *** contrast,stable ice-dynamics are suggested from ice-velocity measurements made each year between 1993-2012,which are on average 1063 m yr-1,with limited interannual variability and no significant trend; moreover,there is no apparent relationship between ice-velocity variability and calving *** degree to which the massive calving events in 2010 and 2012 represent natural episodic variability or a response to atmospheric and/or oceanic changes remains speculative; however,melt-induced weakening of the floating ice tongue in recent years is strongly suggested.

关键词： Greenland outlet glaciers iceberg calving satellite remote sensing

Diapycnal Mixing in Transient Responses of the Atlantic Meridional Overturning Circulation in an Enhanced Freshwater Perturbation Experiment

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Atmospheric and Oceanic Science Letters 2010年第4期3卷 201-206页

作者： Helge DRANGE Odd Helge OTTER nansen-zhu international research centre Institute of Atmospheric PhysicsChinese Academy of Sciences nansen Environmental and Remote Sensing Center/Bjerknes centre for Climate research

It has been reported recently that the simulated Atlantic meridional overturning circulation(AMOC) using the coupled Bergen climate model(BCM) showed initial intensity declines followed by gradual recoveries over a 150-year enhanced freshwater input ***-dependent oceanic diapycnal mixing has been hypothesized as a reason for the simulated recovery of the *** study investigated the role of diapycnal mixing in transient responses of simulated *** results showed that stratification-dependent diapycnal mixing can cause stronger upwelling of deep water in the tropical Atlantic than that produced under conditions of fixed diapycnal ***,simulated AMOCs were more sensitive to active stratification-dependent diapycnal mixing than fixed ***,stratification-dependent diapycnal mixing cannot be conclusively singled out as the critical cause of the recoveries of simulated AMOCs under enhanced-freshwater inputs.

关键词： diapycnal mixing western tropical North Atlantic freshwater experiment

Zones of Openness China’s reforms in its free trade zones offer opportunities to the world

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ChinAfrica 2024年第8期16卷 24-25页

作者： ZHAO ZHONGXIU KONG QINGFENG zhu YONGBIAO University of international Business and Economics School of Economics Shandong University Shandong University Free Trade Zone research Institute School of Politics and international Relations Lanzhou University research centre for the Belt and Road of Lanzhou University

Since the 18th National Congress of the Communist Party of China held in 2012,the construction of pilot free trade zone has emerged as a strategically important approach for China’s reform and opening up *** zones exemplify China’s proactive and open strategy,serving as a key driver for promoting high-quality *** September 2013,China launched its first pilot free trade zone,China(Shanghai)Pilot Free Trade *** the past decade,21 additional pilot free trade zones have been established across the *** expansion has created a comprehensive reform and opening up innovation agenda that spans the eastern,western,southern,northern,and central regions,while integrating coastal,inland,and border areas.

关键词： Zone inland integrating