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Advances in Atmospheric Sciences 2012年第1期29卷 36-46页

作者： ZHOU Feifan MU Mu Laboratory of Cloud-Precipitation Physics and Severe Storms Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029 Key Laboratory of Ocean Circulation and Wave Institute of OceanologyChinese Academy of SciencesQingdao 266071

In this study, the ilnpacts of horizontal resolution on the conditional nonlinear optimal perturbation （CNOP） and on its identified sensitive areas were investigated for tropical cyclone predictions. Three resolutions, 30 km, 60 km, and 120 kin, were studied for three tropical cyclones, TC Mindulle （2004）, TC Meari （2004）, and TC Matsa （2005）. Results show that CNOP may present different structures with different resolutions, and the major parts of CNOP become increasingly localized with increased horizontal resolution. CNOP produces spiral and baroclinic structures, which partially account for its rapid amplification. The differences in CNOP structures result in different sensitive areas, but there are common areas for the CNOP-identified sensitive areas at various resolutions, and the size of the common areas is different from case to case. Generally, the forecasts benefit more from the reduction of the initial errors in the sensitive areas identified using higher resolutions than those using lower resolutions. However, the largest improvement of the forecast can be obtained at the resolution that is not the highest for some cases. In addition, the sensitive areas identified at lower resolutions are also helpful for improving the forecast with a finer resolution, but the sensitive areas identified at the same resolution as the forecast would be the most beneficial.

关键词： horizontal resolution CNOP sensitive area TC prediction

An Effective Configuration of Ensemble Size and horizontal resolution for the NCEP GEFS

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Advances in Atmospheric Sciences 2012年第4期29卷 782-794页

作者：麻巨慧 Yuejian ZHU Richard WOBUS Panxing WANG Key Laboratory of Meteorological Disaster of Ministry of Education Nanjing University of Information Science ＆ Technology Nanjing 210044 Environmental Modeling Center/NCEP/NOAA Camp Springs MD 20746 USA UCAR Boulder CO 80307 USA I.M. Systems Group Inc. （IMSG） at the Environmental Modeling Center/NCEP/NOAA Camp Springs MD 20746 USA

Two important questions are addressed in this paper using the Global Ensemble Forecast System （GEFS） from the National Centers for Environmental Prediction （NCEP）：（1） How many ensemble members are needed to better represent forecast uncertainties with limited computational resources？（2） What is tile relative impact on forecast skill of increasing model resolution and ensemble size？ Two-month experiments at T126L28 resolution were used to test the impact of varying the ensemble size from 5 to 80 members at the 500- hPa geopotential height. Results indicate that increasing the ensemble size leads to significant improvements in the performance for all forecast ranges when measured by probabilistic metrics, but these improvements are not significant beyond 20 members for long forecast ranges when measured by deterministic metrics. An ensemble of 20 to 30 members is the most effective configuration of ensemble sizes by quantifying the tradeoff between ensemble performance and the cost of computational resources. Two representative configurations of the GEFS the T126L28 model with 70 members and the T190L28 model with 20 members, which have equivalent computing costs--were compared. Results confirm that, for the NCEP GEFS, increasing the model resolution is more （less） beneficial than increasing the ensemble size for a short （long） forecast range.

关键词： NCEP operational GEFS ensemble size horizontal resolution ensemble mean tbrecast probabilistic forecast

INFLUENCE OF MODEL horizontal resolution ON THE INTENSITY AND STRUCTURE OF RAMMASUN

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Journal of Tropical Meteorology 2018年第1期24卷 15-28页

作者： WANG Chen-xi ZENG Zhi-hua Shanghai Typhoon Institute CMA Shanghai 200030 China

We use the WRF(V3.4) model as the experimental model and select three horizontal resolutions of 15, 9,and 3 km to research the influence of the model's horizontal resolution on the intensity and structure of the super-strong typhoon Rammasun(1409) in 2014. The results indicate that the horizontal resolution has a very large impact on the intensity and structure of Rammasun. The Rammasun intensity increases as the horizontal resolution increases. When the horizontal resolution increases from 9 km to 3 km, the enhancement of intensity is more obvious, but the strongest intensity simulated by 3 km horizontal resolution is still weaker than the observed strongest intensity. Along with the increase of horizontal resolution, the horizontal scale of the Rammasun vortex decreases, and the vortex gradually contracts toward its center. The vortex structure changes from loose to compact and deep. The maximum wind radius,thickness of the eye wall, and outward inclination of the eye wall with height decrease, and the wind in the inner core region, updraft motion along the eye wall, and strength of the warm core become stronger. Additionally, the pressure gradient and temperature gradient of the eye wall region increase, and the vortex intensity becomes stronger. When the horizontal resolution increases from 9 km to 3 km, the change in the Rammasun structure is much larger than the change when the horizontal resolution increases from 15 km to 9 km. When the model does not employ the method of convection parameterization, the Rammasun intensity simulated with 3 km horizontal resolution is slightly weaker than the intensity simulated with 3 km horizontal resolution when the Kain-Fritsch(KF) convection parameterization scheme is adopted, while the intensity simulated with 9 km horizontal resolution is much weaker than the intensity simulated with 9 km horizontal resolution when the KF scheme is adopted. The influence of the horizontal resolution on the intensity and structure of Ram

关键词： horizontal resolution Rammasun intensity structure

THE EFFECT OF MODEL horizontal resolution ON THE PRECIPITATION OF RAMMASUN

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Journal of Tropical Meteorology 2018年第3期24卷 263-279页

作者： WANG Chen-xi ZENG Zhi-hua Shanghai Typhoon Institute CMA Shanghai 200030 China

This paper investigates the effect of horizontal resolution on the precipitation of the super typhoon Rammasun(1409). The experiment uses WRF(V3.4) model with resolutions of 15 km, 9 km and 3 km. The results suggest that the simulated Rammasun rain band shapes and distributions at different horizontal resolutions are nearly the same. When the resolution is increased from 15 km to 9 km and then to 3 km, heavy precipitation is observed to spread in all directions from a concentrated distribution, especially when the resolution is increased from 9 km to 3 km. The 6 h and 1 h heavy precipitations also show a more significant comma-shape distribution. Moreover, the water vapor distribution shows the same characteristics as the heavy precipitation with a notably enhanced ascending movement and a decreased height of the strongest ascending movement. Of the three resolutions, the precipitation distribution simulated at 3 km resolution is the closest to the observed distribution; however, there is still a noticeable difference between the simulated precipitation and the actual observation. With the absence of the convection parameterization in the model, the precipitation distributions simulated at 9 km and 3 km resolutions demonstrate the same features as when the KF convection parameterization is applied. However, the simulated precipitations at these two resolutions are smaller than those obtained with the KF scheme. Meanwhile the difference between the simulated precipitations at these two resolutions is also smaller than that in the latter case. In general, when KF scheme is applied to the model, the simulation effect of Rammasun precipitation is better than that obtained without the convection parameterization scheme.

关键词： horizontal resolution Rammasun precipitation simulation

THE IMPACT OF horizontal resolution ON THE INTENSITY AND MICROSTRUCTURE OF SUPER TYPHOON USAGI

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Journal of Tropical Meteorology 2019年第1期25卷 24-33页

作者： WEN Ying-fang LIU Yu-di TAN Wei-cai PENG Ke-man CHEN Hai-feng College of Meteorology and Oceanography Defense University of Science and Technology Guangzhou Meteorological Bureau Unit No.75839 of People's Liberation Army Guiyang Meteorological Bureau

Typhoon Usagi(1319) was simulated by using the Advanced Weather Research and Forecasting numerical model(WRF) with different horizontal resolution to understand the impact of horizontal resolution on the intensity and characteristics of typhoon's microstructures(including dynamic and microphysical structure). The simulated results show that the improvement of horizontal resolution from 5 km to 1 km has little impact on the track which is comparable to real results, but has a significant impact on the intensity and microstructures, and especially, the impact on wind speed at 10 m height, the vertical movement and precipitation intensity is the greatest. When the resolution is increased to 1 km, the intensity and characteristics of typhoon's microstructures can be simulated better. In lower resolution simulations, some structural characteristics, including more asymmetrical and more outward tilted eyewall, and less water vapor flux on sea surface, work together to weaken typhoon intensity.

关键词： typhoon horizontal resolution microstructure Usagi numerical simulation

Modeling Arctic Intermediate Water: The effects of Neptune parameterization and horizontal resolution

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Advances in Polar Science 2013年第2期24卷 98-105页

作者： LI Xiang SU Jie WANG Zeliang ZHAO Jinping Key Laboratory of Physical Oceanography Ministry of Education College of Physical and Environmental Oceanography Ocean University of China Bedford Institute of Oceanography Department of Fisheries & Oceans

Arctic Intermediate Water （AIW）, advected from the North Atlantic Ocean, has a potential influence on climate in the Arctic region, but is poorly simulated in coarse resolution models. In this study, a coupled ice-ocean model is used to investigate features of AIW by conducting two sensitivity experiments based on Neptune parameterization and horizontal resolution. The re- suits show that both experiments improve the modeling of temperature profiles in the western Eurasian Basin, mainly as a result of more realistic volume and heat transport through the Fram Strait. Topographical flows are well reproduced using Neptune parame- terization or a finer horizontal resolution. In the eddy-permitting model with relatively higher resolution, the velocity field is more realistic than in the Neptune parameterization model, and complex inflow and outflow belts of barotropic structure are well repro- duced. The findings of this study suggest that increased model resolution, as provided by an eddy-resolving model, is needed to reproduce realistic circulation and thermohaline structure in the Arctic, since the Rossby radius of deformation is only several kilometers in the Arctic Ocean. This paper focuses on the external heat input rather than internal mixing process, and obtains a conclusion that the heat input from the Fram Strait is a main factor to reproduce AIW in the Eurasian Basin successfully, at least for the western part.

关键词： Arctic modeling Arctic Intermediate Water Neptune parameterization horizontal resolution

Characteristics of the Asian–Pacific Oscillation in Boreal Summer Simulated by BCC_CSM with Different horizontal resolutions

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Advances in Atmospheric Sciences 2016年第12期33卷 1401-1412页

作者： Yazhou ZHANG Zhijie LIAO Yaocun ZHANG Feng NIE School of Atmospheric Sciences Nanjing UniversityNanjing 210023 PLA 61936 Troop Haikou 571100

The summer Asian-Pacific Oscillation （APO） is a major teleconnection pattern that reflects the zonal thermal contrast between East Asia and the North Pacific in the upper troposphere. The performance of Beijing Climate Center Climate System Models （BCC_CSMs） with different horizontal resolutions, i.e., BCC_CSM1.1 and BCC_CSM1.1 （m）, in reproducing APO interannual variability, APO-related precipitation anomalies, and associated atmospheric circulation anomalies, is evaluated. The results show that BCC_CSMI.I（m） can successfully capture the interannual variability of the summer APO index. It is also more capable in reproducing the APO＇s spatial pattern, compared to BCC_CSMI.1, due to its higher horizontal resolution. Associated with a positive APO index, the northward-shifted and intensified South Asian high, strengthened extratropical westerly jet, and tropical easterly jet in the upper troposphere, as well as the southwesterly monsoonal flow over North Africa and the Indian Ocean in the lower troposphere, are realistically represented by BCC_CSM1.1 （m）, leading to an improvement in reproducing the increased precipitation over tropical North Africa, South Asia, and East Asia, as well as the decreased precipitation over subtropical North Africa, Japan, and North America. In contrast, these features are less consistent with observations when simulated by BCC_CSM1.1. Regression analysis further indicates that surface temperature anomalies over the North Pacific and the southern and western flanks of the Tibetan Plateau are reasonably reproduced by BCC_CSM 1.1 （m）, which contributes to the substantial improvement in the simulation of the characteristics of summer APO compared to that of BCC_CSM1.1.

关键词： Asian-Pacific Oscillation BCC_CSM horizontal resolution simulation

Decadal Methane Emission Trend Inferred from Proxy GOSAT XCH4 Retrievals:Impacts of Transport Model Spatial resolution

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Advances in Atmospheric Sciences 2022年第8期39卷 1343-1359页

作者： Sihong ZHU Liang FENG Yi LIU Jing WANG Dongxu YANG Carbon Neutrality Research Center Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China National Centre for Earth Observation University of EdinburghEdinburghEH93FFUK University of Edinburgh EdinburghEH93FFUK University of Chinese Academy of Sciences Beijing 100049China

In recent studies,proxy XCH_(4)retrievals from the Japanese Greenhouse gases Observing SATellite(GOSAT)have been used to constrain top-down estimation of CH_(4)***,the resulting interannual variations often show significant discrepancies over some of the most important CH_(4)source regions,such as China and Tropical South America,by causes yet to be *** study compares monthly CH_(4)flux estimates from two parallel assimilations of GOSAT XCH_(4)retrievals from 2010 to 2019 based on the same Ensemble Kalman Filter(EnKF)framework but with the global chemistry transport model(GEOS-Chem v12.5)being run at two different spatial resolutions of 4°×5°(R4,lon×lat)and 2°×2.5°(R2,lon×lat)to investigate the effects of resolution-related model errors on the derived long-term global and regional CH_(4)emission *** found that the mean annual global methane emission for the 2010s is 573.04 Tg yr^(-1)for the inversion using the R4 model,which becomes about 4.4 Tg yr^(-1)less(568.63 Tg yr^(-1))when a finer R2 model is used,though both are well within the ensemble range of the 22 top-down results(2008-17)included in the current Global Carbon Project(from 550 Tg yr^(-1)to 594 Tg yr^(-1)).Compared to the R2 model,the inversion based on the R4 tends to overestimate tropical emissions(by 13.3 Tg yr^(-1)),which is accompanied by a general underestimation(by 8.9 Tg yr^(-1))in the *** a dipole reflects differences in tropical-mid-latitude air exchange in relation to the model’s convective and advective schemes at different *** two inversions show a rather consistent long-term CH_(4)emission trend at the global scale and over most of the continents,suggesting that the observed rapid increase in atmospheric methane can largely be attributed to the emission growth from North Africa(1.79 Tg yr^(-2)for R4 and 1.29 Tg yr^(-2)for R2)and South America Temperate(1.08 Tg yr^(-2)for R4 and 1.21 Tg yr^(-2)for R2)during the first half of the 2010s,an

关键词： methane emissions long-term trend horizontal resolution

On the Importance of High-resolution in Large-Scale Ocean Models

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Advances in Atmospheric Sciences 2021年第10期38卷 1621-1634页

作者： Eric *** Xiaobiao XU Center for Ocean-Atmospheric Prediction Studies(COAPS) Florida State UniversityTallahasseeFL32310USA

Eddying global ocean models are now routinely used for ocean prediction,and the value-added of a better representation of the observed ocean variability and western boundary currents at that resolution is currently being evaluated in climate *** overview article begins with a brief summary of the impact on ocean model biases of resolving eddies in several global ocean-sea ice numerical ***,a series of North and Equatorial Atlantic configurations are used to show that an increase of the horizontal resolution from eddy-resolving to submesoscale-enabled together with the inclusion of high-resolution bathymetry and tides significantly improve the models’abilities to represent the observed ocean variability and western boundary ***,the computational cost of these simulations is extremely large,and for these simulations to become routine,close collaborations with computer scientists are essential to ensure that numerical codes can take full advantage of the latest computing architecture.

关键词： ocean modeling numerical models horizontal resolution boundary currents

Representation of the ENSO Combination Mode and its Asymmetric SST Response in Different resolutions of HadGEM3

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Advances in Atmospheric Sciences 2018年第8期35卷 167-180页

作者： Jianghua WAN Hongli REN Peili WU Laboratory for Climate Studies and CMA-NJU Joint Laboratory for Climate Prediction Studies National Climate Center China Meteorological Administration Beijing 100081 China Department of Atmospheric Sciences School of Environment Studies University of Geoscience Wuhan 430074 China Met Office Hadley Center Exeter EX1 3PB UK

Previous studies have revealed a combination mode （C-mode） occurring in the Indo-Pacific region, arising from nonlinear interactions between ENSO and the western Pacific warm pool annual cycle. This paper evaluates the simulation of this C-mode and its asymmetric SST response in HadGEM3 and its resolution sensitivity using three sets of simulations at horizontal resolutions of N96, N216 and N512. The results show that HadGEM3 can capture well the spatial pattern of the C-mode associated surface wind anomalies, as well as the asymmetric response of SST in the tropical Pacific, but it strongly overestimates the explained variability of the C-mode compared to the ENSO mode. The model with the three resolutions is able to reproduce the distinct spectral peaks of the C-mode at the near annual combination frequencies, but the performance in simulating the longer periods is not satisfactory, presumably due to the unrealistic simulation of the ENSO mode. Increasing the horizontal resolution can improve the consistency between atmospheric and oceanic representations of the C-mode, but not necessarily enhance the accuracy of C-mode simulation compared with observation.

关键词： ENSO combination mode asymmetric response Nifio-A index HadGEM3 horizontal resolution