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Multi-scale Incremental Analysis Update Scheme and Its Application to Typhoon Mangkhut(2018)Prediction

Advances in Atmospheric Sciences 2023年第1期40卷 95-109页

作者： Yan GAO Jiali FENG Xin XIA Jian SUN Yulong MA Dongmei CHEN qilin wan Guangdong-Hong Kong-Macao Greater Bay Area Weather Research Center for Monitoring Warning and Forecasting Shenzhen 518038China CMA Earth System Modeling and Prediction Centre China Meteorological AdministrationBeijing 100081China

In the traditional incremental analysis update(IAU)process,all analysis increments are treated as constant forcing in a model’s prognostic equations over a certain time window.This approach effectively reduces high-frequency oscillations introduced by data assimilation.However,as different scales of increments have unique evolutionary speeds and life histories in a numerical model,the traditional IAU scheme cannot fully meet the requirements of short-term forecasting for the damping of high-frequency noise and may even cause systematic drifts.Therefore,a multi-scale IAU scheme is proposed in this paper.Analysis increments were divided into different scale parts using a spatial filtering technique.For each scale increment,the optimal relaxation time in the IAU scheme was determined by the skill of the forecasting results.Finally,different scales of analysis increments were added to the model integration during their optimal relaxation time.The multi-scale IAU scheme can effectively reduce the noise and further improve the balance between large-scale and small-scale increments in the model initialization stage.To evaluate its performance,several numerical experiments were conducted to simulate the path and intensity of Typhoon Mangkhut(2018)and showed that:(1)the multi-scale IAU scheme had an obvious effect on noise control at the initial stage of data assimilation;(2)the optimal relaxation time for large-scale and small-scale increments was estimated as 6 h and 3 h,respectively;(3)the forecast performance of the multi-scale IAU scheme in the prediction of Typhoon Mangkhut(2018)was better than that of the traditional IAU scheme.The results demonstrate the superiority of the multi-scale IAU scheme.

关键词： multi-scale incremental analysis updates optimal relaxation time 2-D discrete cosine transform GRAPES_Meso Typhoon Mangkhut(2018)

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Ensemble Based Diagnosis of the Track Errors of Super Typhoon Mangkhut(2018)

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Journal of Meteorological Research 2020年第2期34卷 353-367页

作者： Ling HUANG qilin wan Chunxia LIU Huijun HUANG Institute of Tropical and Marine Meteorology of China Meteorological Administration Guangzhou 510000

Super Typhoon Mangkhut(2018)was the most high-impact typhoon in 2018 because of its long lifespan and significant intensity.The operational track forecasts in the short-to-medium range(deterministic and probabilistic forecast)showed a great uncertainty and the forecast landing points varied with different lead times.This study applied ensembles of high-resolution ECMWF forecasts to investigate the major factors and mechanisms of the bias production of the Mangkhut forecast track.The ensembles with the largest track bias were analyzed to examine the possible bias associated factors.The results suggested that environmental steering flows were the main cause for the erroneous southward track error with a variance contribution of 72%.The tropical cyclone(TC)size difference and the interaction of the TC with the subtropical high(SH)were other two key factors that contributed to the track error.Particularly,larger TCs may have led to a stronger erosion of the southern part of the SH,and thus induced significant changes in the large-scale environment and eventually resulted in an additional northward movement of TC.

关键词： Super Typhoon Mangkhut ECMWF ensemble tropical cyclone track

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An Initialization Scheme for Weak Tropical Cyclones in the South China Sea

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Journal of Meteorological Research 2021年第2期35卷 358-370页

作者： Jihang LI qilin wan Daosheng XU Yanyan HUANG Xubin ZHANG Guangzhou Institute of Tropical and Marine Meteorology China Meteorological AdministrationGuangzhou 510640

Variations in the initial structure of tropical cyclones(TCs) inevitably affect prediction results;however, the bogus model cannot accurately describe the structure of a weak tropical cyclone with increased initial field resolution. This study aims to construct a model to improve the prediction of weak TC in southern China. Based on the ECMWF 0.1° analysis data, several vortices were filtered out from tropical depressions and tropical storms in 2018 and 2019 to represent a weak TC reservoir in the South China Sea. For different simulation objects, filtered vortices were combined with the TC environmental field to form ensemble members. The observed TC information was assimilated for simulating TCs Bebinca, Mun, and Ewiniar to verify the feasibility of the proposed model, based on the Global/Regional Assimilation and Prediction Enhanced System(GRAPES) 9-km model developed by the Guangzhou Institute of Tropical and Marine Meteorology. The results show that the initialization scheme of the weak tropical cyclone model improved the intensity prediction of the TC by 26.81%(Bebinca), 18.65%(Mun), and 47.00%(Ewiniar), compared with the control experiment. Because typhoon intensity forecasting has not notably improved for many years, this scheme has certain scientific and operational significance.

关键词： tropical cyclones(TCs) intensity forecast initialization scheme for weak TC

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Effect of Aerosol Particles on Orographic Clouds:Sensitivity to Autoconversion Schemes

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Advances in Atmospheric Sciences 2020年第2期37卷 229-238页

作者： Hui XIAO Yan YIN Pengguo ZHAO qilin wan Xiantong LIU Guangzhou Institute of Tropical and Marine Meteorology China Meteorological AdministrationGuangzhou 510641China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science and TechnologyNanjing 210044China College of Atmospheric Science Chengdu University of Information&TechnologyChengdu 610225China

Aerosol particles can serve as cloud condensation nuclei(CCN)to influence orographic clouds.Autoconversion,which describes the initial formation of raindrops from the collision of cloud droplets,is an important process for aerosol-cloud-precipitation systems.In this study,seven autoconversion schemes are used to investigate the impact of CCN on orographic warm-phase clouds.As the initial cloud droplet concentration is increased from 100 cm^(-3)to 1000 cm^(-3)(to represent an increase in CCN),the cloud water increases and then the rainwater is suppressed due to a decrease in the autoconversion rate,leading to a spatial shift in surface precipitation.Intercomparison of the results from the autoconversion schemes show that the sensitivity of cloud water,rainwater,and surface precipitation to a change in the concentration of CCN is different from scheme to scheme.In particular,the decrease in orographic precipitation due to increasing CCN is found to range from-87%to-10%depending on the autoconversion scheme.Moreover,the surface precipitation distribution also changes significantly by scheme or CCN concentration,and the increase in the spillover(ratio of precipitation on the leeward side to total precipitation)induced by increased CCN ranges from 10%to 55%under different autoconversion schemes.The simulations suggest that autoconversion parameterization schemes should not be ignored in the interaction of aerosol and orographic cloud.

关键词： orographic cloud precipitation autoconversion aerosol particles

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Raindrop Size Distribution Parameters Retrieved from Guangzhou S-band Polarimetric Radar Observations

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Journal of Meteorological Research 2018年第4期32卷 571-583页

作者： Xiantong LIU qilin wan Hong wanG Hui XIAO Yu ZHANG Tengfei ZHENG Lu FENG Institute of Tropical and Marine Meteorology of China Meteorological Administration Guangzhou 510640 Guangzhou Meteorological Observatory Guangzhou 511430

According to the statistical shape-slope （μ-A） relationship observed for the first time by several 2D-Video-Distro-meters （2DVD） in southern China, a constrained gamma （C-G） model was proposed for the retrieval of rain drop size distributions （DSDs） from Guangzhou S-band polarimetric radar observations. Two typical precipitation processes were selected to verify the accuracy of the retrieval scheme. The p-A relationship： A = 0.0241μ^2 ＋ 0.867μ ＋ 2.453 was obtained based on the 2DVD observation results from at Huizhou Longmen station, which is a very representat-ive location in the area. Relying on the Guangzhou polarimetric radar measurements of radar reflectivity （ZHH） and differential reflectivity （ZDR）, the gamma （F） size distribution parameters （No, μ, and A） can be retrieved by the C-G model retrieval scheme. The results show that the Guangzhou polarimetric radar retrievals of DSDs were close to the 2DVD observations at Guangzhou Maofengshan station. The rain rate, mass mean diameter, and normalized inter-cept parameter of radar retrievals were in good agreement with the 2DVD observations, and the relative errors were less than 10%. The overall accuracy of the retrieval scheme was high. The retrieval scheme has established the rela-tionship between the polarimetric radar measurements and gamma size distribution parameters. It will be helpful to in-depth research and application of the dual-polarization radar data in microphysical precipitation processes analysis, as well as convection-resolved numerical model data assimilation and prediction effect evaluation.

关键词： Guangzhou S-band polarimetric radar 2D-Video-Disdrometer raindrop size distribution retrieval microphysics

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Comparative evaluation of the impact of GRAPES and MM5 meteorology on CMAQ prediction over Pearl River Delta, China

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Particuology 2018年第5期16卷 88-97页

作者： Tao Deng Yiang Chen qilin wan Yanxia Zhang Xuejiao Deng Yanyan Huang Guangfeng Dai Fei Li Institute of Tropical and Marine Meteorology/Guangdong Provincial Key Laboratory of Regional Numerical Weather Prediction China Meteorological AdministrationGuangzhou 510080China Key Laboratory of Meteorological Disaster Ministry of EducationJoint International Research Laboratory of Climate and Environment ChangeCollaborative Innovation Center on Forecast and Evaluation of Meteorological DisastersKey Laboratory for Aerosol-Cloud-Precipitation of China Meteorological AdministrationNanjing University olin formation Science &TechnologyNanjing210044China

The community multiscale air quality (CMAQ) model was used to forecast air quality over the Pearl River Delta region from December 2013 to January 2014.The pollution forecasting performance of CMAQ coupled with two different meteorological models,i.e.,the global/regional assimilation and prediction system (GRAPES) and the fifth-generation mesoscale model (MM5),was assessed by comparison with observational data.The effects of meteorological factors and physicochemical processes on the forecast results were discussed through process analysis.The results showed that both models exhibited good performance but that of GRAPES-CMAQ was better.GRAPES was superior in predicting the overall variation tendencies of meteorological fields,but it showed large deviations in atmospheric pressure and wind speed.This contributed to the higher correlation coefficients of the pollutants with GRAPES-CMAQ but with greater deviations.The underestimations of nitrate and ammonium salt contributed to the underestimations of both particulate matter and extinction coefficients.Source emissions made the only positive contributions to surface layer SO2,CO,and NO.It was found that O3 originated primarily from horizontal and vertical transport and that its consumption was predominantly via chemical processes.Conversely,NO2 was found derived primarily from chemical production.

关键词： Air quality Numerical simulation Global/regional assimilation and prediction system (GRAPES) Community multiscale air quality (CMAQ) Process analysis

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The Simulation of Five Tropical Cyclones by Sample Optimization of Ensemble Forecasting Based on the Observed Track and Intensity

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Advances in Atmospheric Sciences 2021年第10期38卷 1763-1777页

作者： Jihang LI Zhiyan ZHANG Lu LIU Xubin ZHANG Jingxuan QU and qilin wan Guangzhou Institute of Tropical and Marine Meteorology Guangzhou 510640China State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China

The quality of ensemble forecasting is seriously affected by sample quality.In this study,the distributions of ensemble members based on the observed track and intensity of tropical cyclones(TCs)were optimized and their influence on the simulation results was analyzed.Simulated and observed tracks and intensities of TCs were compared and these two indicators were combined and weighted to score the sample.Samples with higher scores were retained and samples with lower scores were eliminated to improve the overall quality of the ensemble forecast.For each sample,the track score and intensity score were added as the final score of the sample with weight proportions of 10 to 0,9 to 1,8 to 2,7 to 3,6 to 4,5 to 5.These were named as“tr”,“91”,“82”,“73”,“64”,and“55”,respectively.The WRF model was used to simulate five tropical cyclones in the northwestern Pacific to test the ability of this scheme to improve the forecast track and intensity of these cyclones.The results show that the sample optimization effectively reduced the track and intensity error,“55”usually had better performance on the short-term intensity prediction,and“tr”had better performance in short-term track prediction.From the overall performance of the track and intensity simulation,“91”was the best and most stable among all sample optimization schemes.These results may provide some guidance for optimizing operational ensemble forecasting of TCs.

关键词： tropical cyclones ensemble forecast sample optimization observed track and intensity

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Improvement of the Surface Pressure Operator in GRAPES and Its Application in Precipitation Forecasting in South China

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Advances in Atmospheric Sciences 2013年第2期30卷 354-366页

作者： HUANG Yanyan XUE Jishan wan qilin CHEN Zitong DING Weiyu ZHANG Chengzhong Guangzhou Institute of Tropical and Marine Meteorology Guangzhou 510080 ~tate Key Laboratory of Severe Weather Chinese Academy of Meteorological Sciences Beijing 100081

In this study we investigated the problems involved in assimilating surface pressure in the current global and regional assimilation and prediction system, GRAPES. A new scheme of assimilating surface pressure was proposed, including a new interpolation scheme and a refreshed background covariance. The new scheme takes account of the differences between station elevation and model topography, and it especially deals with stations located at elevations below that of the first model level. Contrast experiments were conducted using both the original and the new assimilation schemes. The influence of the new interpolation scheme and the updated background covariance were investigated. Our results show that the new interpolation scheme utilized more observations and improved the quality of the mass analysis. The background covariance was refreshed using statistics resulting from the technique proposed by Parrish and Derber in 1992. Experiments show that the updated vertical covariance may have a positive influence on the analysis at higher levels of the atmosphere when assimilating surface pressure. This influence may be more significant if the quality of the background field at high levels is poor. A series of assimilation experiments were performed to test the validity of the new scheme. The corresponding simulation experiments were conducted using the analysis of both schemes as initial conditions. The results indicated that the new scheme leads to better forecasting of sea level pressure and precipitation in South China, especially the forecast of moderate and heavv rain.

关键词： GRAPES system surface pressure assimilation background covariance numerical simulation

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碳化钢渣基胶凝材料在道路水稳层中的应用性能评价及机理研究

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水泥工程 2024年第2期 1-5页

作者：陆振伟张栋锐华苏东张亚男任晓健万奇林胡玉冰袁志洲冯贵洋江苏众信工程投资项目管理咨询有限公司江苏张家港215600 南京工业大学江苏南京211816 江苏绿普资源利用开发有限公司江苏张家港215600 南京理工大学江苏南京210094 南京钜力智能制造技术研究院有限公司江苏南京211100

钢渣存在安定性不良的问题,将钢渣应用于水稳层,会存在钢渣分布不均匀,使试样出现膨胀开裂的现象。通过研究发现,对钢渣基胶凝材料进行碳化处理可以提高其体积稳定性,粒径较细的钢渣能够增大碳化反应面积,有利于提高碳化程度。本文对≥... 详细信息

钢渣存在安定性不良的问题,将钢渣应用于水稳层,会存在钢渣分布不均匀,使试样出现膨胀开裂的现象。通过研究发现,对钢渣基胶凝材料进行碳化处理可以提高其体积稳定性,粒径较细的钢渣能够增大碳化反应面积,有利于提高碳化程度。本文对≥200目钢渣进行碳化处理,研究碳化时间和碳化温度对预碳化钢渣基胶凝材料的体积稳定性影响,并对其碳化机理进行探究;与建筑再生骨料制备水稳层,对其进行无侧限抗压强度和抗冻性测试。结果表明,随着碳化时间的和温度增加,预碳化钢渣基胶凝材料压蒸膨胀率逐渐降低,活性先增高后降低。在常压下,碳化温度为60℃,碳化时间为1.5 h的钢渣基胶凝材料相对活性最高。

关键词：钢渣碳化安定性水稳层

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An Observational Study of the Hygroscopic Properties of Aerosols over the Pearl River Delta Region

An Observational Study of the Hygroscopic Properties of Aero...

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第八届全国优秀青年气象科技工作者学术研讨会

作者： Haobo Tan Yan Yin Xuesong Gu Fei Li P.W.Chan Hanbing Xu Xuejiao Deng qilin wan Key Laboratory for Aerosol-cloud-precipitation of China Meteorological Administration Nanjing University of Information Science and Technology Key Laboratory of Regional Numerical Weather Prediction Institute of Tropical and Marine Meteorology China Meteorological Administration Hong Kong Observatory Experimental Teaching Center Sun Yat-sen University

Hygroscopic growth can significantly affect size distribution and activation of aerosol particles,as well as their effects on human health,atmospheric visibility,and climate.In this study,a H-TDMA（Hygroscopic Tandem Differential Mobility Analyzer）was utilized to measure hygroscopic growth factor and mixing state of aerosol particles at the CAWNET station in Panyu,Guangzhou,China.A statistical analysis of the results show that,at relative humidity（RH）of 90%,for less-hygroscopic particles of 40-200 nm in diameter,the growth factor（gLH）was around 1.13,while the number fraction（NFLH）varied between 0.41±0.136 and 0.26±0.078;for more-hygroscopic particles,the growth factor（gMH）varied between 1.46 and 1.55 with the average equivalent ammonium sulfate ratio（εAS）ranging from 0.63 to 0.68.The differences inεAS among particle of different sizes reveal that more-hygroscopic inorganic salts,such as ammonium sulfate and ammonium nitrate,are of more effective condensation growth for Aitken mode particles.A combined analysis of the probability density function of growth factor（Gf-PDF）and simultaneous meteorological data shows that during clean periods with air masses moving from the north,the particles are more likely to have homogeneous chemical composition,while during polluted or pollution accumulation periods,variations in mean number weighted growth factor（gmean）and NFMH become more pronounced,indicating that locally-emitted aerosol particles tend to be in an externally mixed state and contain a certain proportion of less-hygroscopic particles.This study can help improve our understanding of aerosol hygroscopicity and its impact on the atmospheric visibility and environment.

关键词： H-TDMA aerosol hygroscopicity urban aerosol haze Pearl River Delta

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