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Uncertainty in Tropical Cyclone Intensity Predictions due to Uncertainty in Initial Conditions

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Advances in Atmospheric Sciences 2020年第3期37卷 278-290页

作者： Chenxi WANG Zhihua ZENG Ming YING shanghai typhoon institute china meteorological administration

Focusing on the role of initial condition uncertainty,we use WRF initial perturbation ensemble forecasts to investigate the uncertainty in intensity forecasts of Tropical Cyclone(TC)Rammasun(1409),which is the strongest TC to have made landfall in china during the past 50 *** results indicate that initial condition uncertainty leads to TC forecast uncertainty,particularly for TC *** uncertainty increases with forecast time,with a more rapid and significant increase after 24 *** predicted TC develops slowly before 24 h,and at this stage the TC in the member forecasting the strongest final TC is not the strongest among all ***,after 24 h,the TC in this member strengthens much more than that the TC in other *** variations in convective instability,precipitation,surface upward heat flux,and surface upward water vapor flux show similar characteristics to the variation in TC intensity,and there is a strong correlation between TC intensity and both the surface upward heat flux and the surface upward water vapor *** initial condition differences that result in the maximum intensity difference are smaller than the errors in the analysis *** in initial humidity,and to a lesser extent initial temperature differences,at the surface and at lower heights are the key factors leading to differences in the forecasted TC *** differences in initial humidity and temperature relate to both the overall values and distribution of these parameters.

关键词： uncertainty tropical cyclone intensity initial conditions

Convective Asymmetries Associated with Tropical Cyclone Landfall: β-Plane Simulations

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Advances in Atmospheric Sciences 2010年第4期27卷 795-806页

作者：黄伟梁旭东 shanghai typhoon institute China Meteorological Administration

The physical processes associated with changes in the convective structure of an idealized tropical cyclone （TC） during landfall on a beta-plane were studied using the fifth-generation Pennsylvania State University- National Center for Atmospheric Research Mesoscale Model, version 3 （MM5）. The simulation results suggested that the suppression of moisture supply and increased friction acted to enhance the convection from the left and front quadrants of the TC to the front and right of the TC during different periods of landfall. When surface moisture flux was turned off, convection in other parts of the quadrant was clearly suppressed and the total rainfall was reduced. When surface friction was increased, precipitation showed a marked increase after the TC made landfall. Wetter air at low and intermediate levels, and drier air at high levels around the onshore side of the coastline led to a high value of convective available potential energy （CAPE）. Consequently, convection was enhanced immediately downstream of this area when the surface moisture flux was cut off. When surface friction was increased, the physical process was similar prior to landfall. After landfall, increased convergence at the onshore side of the land resulted in enhanced convection in front of the TC. Consistent with previous findings, our results suggest that during landfall the TC structure changes from one of thermodynamic symmetry to asymmetry due to differential moisture flux between the land and sea surface. The asymmetry of the thermodynamic structure, which can be explained by the distribution of CAPE, causes an asymmetric rainfall structure.

关键词： tropical cyclone landfall convective asymmetry

Analysis of atmospheric turbulence in the upper layers of sea fog

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Chinese Journal of Oceanology and Limnology 2015年第3期33卷 809-818页

作者：李永平郑运霞 shanghai typhoon institute China Meteorological Administration

Atmospheric turbulence plays a vital role in the formation and dissipation of fog. However,studies of such turbulence are typically limited to observations with ultrasonic anemometers less than 100 m above ground. Thus,the turbulence characteristics of upper fog layers are poorly known. In this paper,we present 4-layers of data,measured by ultrasonic anemometers on a wind tower about 400 m above the sea surface; we use these data to characterize atmospheric turbulence atop a heavy sea fog. Large differences in turbulence during the sea fog episode were recorded. Results showed that the kinetic energy,momentum flux,and sensible heat flux of turbulence increased rapidly during the onset of fog. After onset,high turbulence was observed within the uppermost fog layer. As long as this turbulence did not exceed a critical threshold,it was crucial to enhancing the cooling rate,and maintaining the fog. Vertical momentum flux and sensible heat flux generated by this turbulence weakened wind speed and decreased air temperature during the fog. Towards the end of the fog episode,the vertical distribution of sensible heat flux reversed,contributing to a downward momentum flux in all upper layers. Spatial and temporal scales of the turbulence eddy were greater before and after the fog,than during the fog episode. Turbulence energy was greatest in upper levels,around 430 m and 450 m above mean sea level(AMSL),than in lower levels of the fog(390 m and 410 m AMSL); turbulence energy peaked along the mean wind direction. Our results show that the status of turbulence was complicated within the fog; turbulence caused fluxes of momentum and sensible heat atop the fog layer,affecting the underlying fog by decreasing or increasing average wind speed,as well as promoting or demoting air temperature stratification.

关键词： ultrasonic anemometers turbulence characteristics momentum flux sensible heat flux variation in sea fog

An ocean-land-atmosphere coupled model for tropical cyclone landfall processes: The multi-layer ocean model and its verification

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Acta Oceanologica Sinica 2006年第2期25卷 33-48页

作者： DUAN Yihong YU Runling LI Yongping shanghai typhoon institute of china meteorological administration Shanghai 200030China

POM (Princeton ocean model) tentatively taken as the ocean part of an ocean-land atmosphere coupled modcl is verified for the ultimate purpose of studying the landfall process of tropical cyclone (TC) in the western North Pacific. The POM is tested with monthly mean wind stress in the summer and given lateral boundary conditions. The results indicate that the equilibrium state of the ocean is in accordance with the climate mean, with the error in sea surface temperature (salinity) less than 0.5 ℃ (0.5). The simulated occan currents are reasonable as *** numerical experiments are designed to verify the oceanic response to a stationary or moving TC. It is found that the results agree fairly well with the previous work, including both the drop magnitude and the distribution ofsca temperature. Compared with the simple two-layer ocean model used by some other studies, the response of the ocean to a TC is more logical here. The model is also verified in a real case with a TC passing the neighborhood of a buoy station. It is shown that the established ocean model can basically reproduce the sea surface temperature change as observed.

关键词： tropical cyclone ocean coupled model

The Contribution of United States Aircraft Reconnaissance Data to the china meteorological administration Tropical Cyclone Intensity Data:An Evaluation of Homogeneity

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Advances in Atmospheric Sciences 2024年第4期41卷 639-654页

作者： Ming YING Xiaoqin LU shanghai typhoon institute China Meteorological AdministrationShanghai 200030China

This paper investigates the homogeneity of United States aircraft reconnaissance data and the impact of these data on the homogeneity of the tropical cyclone(TC)best track data for the seasons 1949-1987 generated by the china meteorological administration(CMA).The evaluation of the reconnaissance data shows that the minimum central sea level pressure(MCP)data are relatively homogeneous,whereas the maximum sustained wind(MSW)data show both overestimations and spurious abrupt *** comparisons suggest that both the reconnaissance MCP and MSW were well incorporated into the CMA TC best track *** no spurious abrupt changes were evident in the reconnaissance-related best track MCP data,two spurious changepoints were identified in the remainder of the best-track MCP ***,the influence of the reconnaissance MSWs seems to extend to the best track MSWs unrelated to reconnaissance,which might reflect the optimistic confidence in making higher estimates due to the overestimated extreme wind“observations”.In addition,the overestimation of either the reconnaissance MSWs or the best track MSWs was greater during the early decades compared to later decades,which reflects the important influence of reconnaissance data on the CMA TC best track *** wind-pressure relationship(WPR)used in the CMA TC best track dataset is also evaluated and is found to overestimate the MSW,which may lead to inhomogeneity within the dataset between the aircraft reconnaissance era and the satellite era.

关键词： tropical cyclone intensity homogeneity best track aircraft reconnaissance

Climatic variation of tropical cyclones affecting china during the past 50 years

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Science china Earth Sciences 2011年第8期54卷 1226-1237页

作者： YING Ming YANG YuHua CHEN BaoDe ZHANG Wei Laboratory of typhoon Forecast Technique Shanghai Typhoon Institute China Meteorological Administration Shanghai 200030 China

Trends of the tropical cyclones (TCs) influence on china and its four subregions,namely the South china (SC),East china (EC),Northeast china (NEC),and china's inland area (CI),are detected by applying quantile regression to the CMA-STI tropical cyclone best track and related severe wind and precipitation observation *** results indicate that in the past 50 years,the number of TCs affecting china and its four subregions has remained steady,except that the frequency in extremely active years has decreased not only in china as a whole,but also in *** addition,TC activity is found to have weakened over the northwest South china Sea,Guangdong,and Shandong ***,the most important changes in seasonality are found in the first quartiles of the number of days of TCs affecting *** the extreme values of sustained winds all have decreasing trends,the extreme values of wind gusts are completely different not only among different orders of extreme values,but also among different ***,the trends of extreme TC rainfall,namely the maximum storm precipitation and the maximum 1-h precipitation,are not significant.

关键词： tropical cyclone wind and precipitation climatic variation china

Analysis and prognosis of tropical cyclone genesis over the western North Pacific on the background of global warming

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Acta Oceanologica Sinica 2007年第1期26卷 23-34页

作者： LI Yongping WANG Xiaofeng YU Runling QIN Zenghao Open Laboratory for typhoon Research Shanghai Typhoon Institute China Meteorological Administration Shanghai 200030

As revealed by the observational study, there are more tropical cyclones generated over the western North Pacific from the early 1950s to the early 1970s in the 20th century and less tropical cyclones from the mid-1970s to the present. The decadal change of ＂tropical cyclones activities are closely related to the decadal changes of atmospheric general circulation in the troposphere, which provide favorable or unfavorable conditions for the formation of tropical cyclone. Furthermore, based on the simulation of corresponding atmospheric general circulation from a coupled climate model under the schemes of Intergovemmental Panel on Climate Change （IPCC）,special report on emission scenarios （SRES） A2 and B2 emissions scenarios an outlook on the tropical cyclone frequency generated over the western North Pacific in the coming half century is presented. It is indicated that in response to the global climate change the general circulation of atmosphere would become unfavorable for the formation of tropical cyclone as a whole and the frequency of tropical cyclones formation would likely decrease by 5% within the next half century, although more tropical cyclones would appear during a short period in it.

关键词： IPCC SRES A2 and B2 general circulation anomaly frequency of tropical cyclone

THE EFFECTS OF STATION NETWORK DENSITY ON STATISTICAL ANALYSES OF TROPICAL CYCLONE PRECIPITATION

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Journal of Tropical Meteorology 2018年第4期24卷 421-432页

作者： LU Xiao-qin YU Hui YING Ming QI Liang-bo shanghai typhoon institute China Meteorological Administration shanghai meteorological Center Shanghai Meteorological Bureau

In this paper, 1416 conventional ground-based meteorological observation stations on the mainland of china were subdivided into groups of differing spatial density. Data from each subgroup were then used to analyze variations in the tropical cyclone(TC) precipitation statistics derived from each subgroup across the mainland of china(excluding Taiwan, Hong Kong, and Macao), as well as in two regions(east china and south china) and three provinces(Guangdong, Hainan, and Jiangxi) between 1981 and 2010. The results showed that for the mainland of china, total precipitation, mean annual precipitation, mean daily precipitation, and its spatial distribution were the same regardless of the spatial density of the stations. However, some minor differences were evident with respect to precipitation extremes and their spatial distribution. Overall, there were no significant variations in the TC precipitation statistics calculated from different station density schemes for the mainland of china. The regional and provincial results showed no significant differences in mean daily precipitation, but this was not the case for the maximum daily precipitation and torrential rain frequency. The maximum daily precipitation calculated from the lower-density station data was slightly less than that based on the higher-density station schemes, and this effect should be taken into consideration when interpreting regional climate statistics. The impact of station density on TC precipitation characteristics was more obvious for Hainan than for Guangdong or Jiangxi provinces. In addition, the effects were greater for south china(including Guangxi Zhuang Autonomous region, Guangdong, and Hainan provinces) than east china(including Shandong, Jiangsu, Zhejiang, shanghai, Fujian, Anhui, and Jiangxi provinces). Furthermore, the analysis proved that the statistical climatic characteristics began to change significantly when the station spacing was between 40 and 50 km,which are close to the mean spa

关键词： station density tropical cyclone precipitation climatic characteristic

PRELIMINARY RESEARCH ON THE RELATIONSHIPS BETWEEN THE INNER CORE SIZE AND OUTER SIZE OF TROPICAL CYCLONES AND THEIR INTENSITY

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Journal of Tropical Meteorology 2014年第4期20卷 308-313页

作者：吴联要雷小途 Zhejiang meteorological Observatory shanghai typhoon institute China Meteorological Administration

Based on the Regional Spectral Model(RSM) re-analysis data from Japan meteorological Agency(JMA) with a horizontal resolution of 20 km and a time interval of 6 h,this study works on the outer and inner core size of 2174 samples of tropical cyclones(TCs) occurring over the western North Pacific between 2001 and *** conclusions have been drawn on the basis of preliminary analysis of the TC inner core size and outer size and their relationship with TC ***,the outer size increase(decrease) helps TCs intensify(weaken).Second,the enlargement(shrinking) of the inner core size helps TCs intensify(weaken) if TCs have a large inner core(with radius of maximum winds larger than 120 km).Contrarily,when TCs have small inner core(with radius of maximum winds smaller than 120 km),the enlargement(shrinking) of the inner core is good for weakening(intensifying) of TCs.

关键词： tropical cyclone size inner core intensity