黑潮延伸体海洋中尺度涡旋:四套数据的比较

在不同的中尺度涡数据中,涡旋的识别,跟踪方法以及物理参数的定义存在差异,因此需要对涡旋结果进行相互比较和验证.本文比较了Chelton,GEM-M,Faghmous和Dong四套中尺度涡数据在黑潮延伸体区域的基本特征.结果表明,各数据的中尺度涡数量,特征和轨迹均存在差异.经过归一化处理后,涡特征的地理分布和时间变化高度相似,特别是Chelton,Fahgmous和Dong三套数据.

LICOM Model Datasets for the CMIP6 Ocean Model Intercomparison Project

The datasets of two Ocean Model Intercomparison Project(OMIP)simulation experiments from the LASG/IAP Climate Ocean Model,version 3(LICOM3),forced by two different sets of atmospheric surface data,are described in this paper.The experiment forced by CORE-II(Co-ordinated Ocean–Ice Reference Experiments,Phase II)data(1948–2009)is called OMIP1,and that forced by JRA55-do(surface dataset for driving ocean–sea-ice models based on Japanese 55-year atmospheric reanalysis)data(1958–2018)is called OMIP2.First,the improvement of LICOM from CMIP5 to CMIP6 and the configurations of the two experiments are described.Second,the basic performances of the two experiments are validated using the climatological-mean and interannual time scales from observation.We find that the mean states,interannual variabilities,and long-term linear trends can be reproduced well by the two experiments.The differences between the two datasets are also discussed.Finally,the usage of these data is described.These datasets are helpful toward understanding the origin system bias of the fully coupled model.

Eddy-resolving Simulation of CAS-LICOM3 for Phase 2 of the Ocean Model Intercomparison Project

A 61-year(1958–2018)global eddy-resolving dataset for phase 2 of the Ocean Model Intercomparison Project has been produced by the version 3 of Chinese Academy of Science,the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics/Institute of Atmospheric Physics(LASG/IAP)Climate system Ocean Model(CAS-LICOM3).The monthly and a part of the surface daily data in this study can be accessed on the Earth System Grid Federation(ESGF)node.Besides the details of the model and experiments,the evolutions and spatial patterns of large-scale and mesoscale features are also presented.The mesoscale features are reproduced well in the high-resolution simulation,as the mesoscale activities can contribute up to 50%of the total SST variability in eddy-rich regions.Also,the large-scale circulations are remarkably improved compared with the low-resolution simulation,such as the climatological annual mean SST(the RMSE is reduced from 0.59°C to 0.47°C,globally)and the evolution of Atlantic Meridional Overturning Circulation.The preliminary evaluation also indicates that there are systematic biases in the salinity,the separation location of the western boundary currents,and the magnitude of eddy kinetic energy.All these biases are worthy of further investigation.

FGOALS-g3 Model Datasets for CMIP6 Flux-Anomaly-Forced Model Intercomparison Project

The Flux-Anomaly-Forced Model Intercomparison Project(FAFMIP)is an endorsed Model Intercomparison Project in phase 6 of the Coupled Model Intercomparison Project(CMIP6).The goal of FAFMIP is to investigate the spread in the atmosphere–ocean general circulation model projections of ocean climate change forced by increased CO2,including the uncertainties in the simulations of ocean heat uptake,global mean sea level rise due to ocean thermal expansion and dynamic sea level change due to ocean circulation and density changes.The FAFMIP experiments have already been conducted with the Flexible Global Ocean–Atmosphere–Land System Model,gridpoint version 3.0(FGOALS-g3).The model datasets have been submitted to the Earth System Grid Federation(ESGF)node.Here,the details of the experiments,the output variables and some baseline results are presented.Compared with the preliminary results of other models,the evolutions of global mean variables can be reproduced well by FGOALS-g3.The simulations of spatial patterns are also consistent with those of other models in most regions except the North Atlantic and the Southern Ocean,indicating large uncertainties in the regional sea level projections of these two regions.

The Super-large Ensemble Experiments of CAS FGOALS-g3

A super-large ensemble simulation dataset with 110 members has been produced by the fully coupled model FGOALS-g3 developed by researchers at the Institute of Atmospheric Physics,Chinese Academy of Sciences.This is the first dataset of large ensemble simulations with a climate system model developed by a Chinese modeling center.The simulation has the largest realizations up to now worldwide in terms of single-model initial-condition large ensembles.Each member includes a historical experiment(1850-2014)and an experiment(2015-99)under the very high greenhouse gas emissions Shared Socioeconomic Pathway scenario(SSP5-8.5).The dataset includes monthly and daily temperature,precipitation,and other variables,requiring storage of 275 TB.Additionally,the surface air temperature(SAT)and land precipitation simulated by the FGOALS-g3 super-large ensemble have been validated and projected.The ensemble can capture the response of SAT and land precipitation to external forcings well,and the internal variabilities can be quantified.The availability of more than 100 realizations will help researchers to study rare events and improve the understanding of the impact of internal variability on forced climate changes.

Two regimes of Atlantic multidecadal oscillation: cross-basin dependent or Atlantic-intrinsic

The Atlantic Multidedal Oscillation(AMO) is a prominent mode of sea surface temperature variability in the Atlantic and incurs significant global influence. Most coupled models failed to reproduce the observed 50–80-year AMO, but were overwhelmed by a 10–30-year AMO. Here we show that the 50–80-year AMO and 10–30-year AMO represent two different AMO regimes. The key differences are:(1) the 50–80-year AMO involves transport of warm and saline Atlantic water into the Greenland-Iceland-Norwegian(GIN)Seas prior to reaching its maximum positive phase, while such a transport is weak for the 10–30-year AMO;(2) the zonality of atmospheric variability associated with the 50–80 year AMO favors the transport of warm and saline water into the GIN Seas;(3) the disappearance of Pacific variability weakens the zonality of atmospheric variability and the transport of warm and saline water into the GIN Seas, leading to the weakening of the 50–80-year AMO. In contrast, the 10–30-year AMO does not show dependence on the variability in Pacific and in the GIN Seas and may be an Atlantic-intrinsic mode. Our results suggest that differentiating these AMO regimes and a better understanding of the cross-basin connections are essential to reconcile the current debate on the nature of AMO and hence to its reliable prediction, which is still lacking in most of coupled models.