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Multi-Factor Intensity Estimation for Tropical Cyclones in the Western North Pacific Based on the Deviation Angle Variance Technique

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Journal of Meteorological Research 2020年第5期34卷 1038-1051页

作者： Wei ZHONG Meng YUAN Hexin YE Xia LUO college of meteorology and Oceanology National University of Defense TechnologyNanjing 211101 Submarine college of Navy Qingdao 266199

In this paper, the infrared cloud images from Fengyun series geostationary satellites and the best track data from the China Meteorological Administration(CMA-BST) in 2015–2017 are used to investigate the effects of two multifactor models, generalized linear model(GLM) and long short-term memory(LSTM) model, for tropical cyclone(TC) intensity estimation based on the deviation angle variance(DAV) technique. For comparison, the typical singlefactor Sigmoid function model(SFM) with the map minimum value of DAV is also used to produce TC intensity estimation. Sensitivity experiments regarding the DAV calculation radius and different training data groups are conducted, and the estimation precision and optimum calculation radius for DAV in the western North Pacific(WNP) are analyzed. The results show that the root-mean-square-error(RMSE) of the single-factor SFM is 8.79–13.91 m s^-1 by using the individual years as test sets and the remaining two years as training sets with the optimum calculation radius of 550 km. However, after selecting and using the high-correlation multiple factors from the same test and training data, the RMSEs of GLM and LSTM models decrease to 5.93–8.68 and 4.99–7.00 m s^-1 respectively, with their own optimum calculation radii of 350 and 400 km. All the sensitivity experiments indicate that the SFM results are significantly influenced by the DAV calculation radius and characteristics of the training set data, while the results of multi-factor models appear more stable. Furthermore, the multi-factor models reduce the optimum radius within the process of DAV calculation and improve the precision of TC intensity estimation in the WNP, which can be chosen as an effective approach for TC intensity estimation in marine areas.

关键词： deviation angle variance(DAV)technique tropical cyclone(TC) intensity estimation

ANNUAL VARIATIONS OF TEMPERATURE ON FOUR URBAN UNDERLYING SURFACES AND FITTING ANALYSIS

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Journal of Tropical meteorology 2013年第2期19卷 138-144页

作者：刘霞王春林景元书麦博儒 Haikou meteorology Bureau Climate Center of Guangdong Province college of Applied meteorology Nanjing University of Information Scienceand Technology Guangzhou Institute of Tropical and Marine meteorology China Meteorological Administration

Based on the observed 2-year temperature data for four kinds of typical urban underlying surfaces,including asphalt, cement, bare land and grass land, the annual variations and influencing factors of landsurface temperature are analyzed. Then fitting equations for surface temperature are established. It is shownthat the annual variation of daily average, maximum and minimum temperature and daily temperature rangeon the four urban underlying surfaces is consistent with the change in air temperature. The difference oftemperature on different underlying surfaces in the summer half year (May to October) is much moreevident than that in the winter half year (December to the following April). The daily average and maximumtemperatures of asphalt, cement, bare land and grass land are higher than air temperature due to theatmospheric heating in the daytime, with that of asphalt being the highest, followed in turn by cement, bareland and grass land. Moreover, the daily average, maximum and minimum temperature on the four urbanunderlying surfaces are strongly impacted by total cloud amount, daily average relative humidity andsunshine hours. The land surface can be cooled (warmed) by increased total cloud amount (relativehumidity). The changes in temperature on bare land and grass land are influenced by both the total cloudamount and the daily average relative humidity. The temperature parameters of the four land surfaces aresignificantly correlated with daily average, maximum and minimum temperature, sunshine hours, dailyaverage relative humidity and total cloud amount, respectively. The analysis also indicates that the range offitting parameter of a linear regression equation between the surface temperature of the four kinds of typicalland surface and the air temperature is from 0.809 to 0.971, passing the F-test with a confidence level of 0.99.

关键词： fitting analysis urban underlying surface land surface temperature

Statistical Characteristics and Mechanistic Analysis of Suddenly Reversed Tropical Cyclones over the Western North Pacific Ocean

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Advances in Atmospheric Sciences 2015年第4期32卷 565-576页

作者： LUO Xia FEI Jianfang HUANG Xiaogang CHENG Xiaoping DING Juli HE Yiqiang college of meteorology and Oceanography PLA University of Science and Technology Beijing Aerospace Control Center

Based on best track data of tropical cyclones（TCs） from the Japan Meteorological Agency, the characteristics of suddenly reversed TCs（SRTCs）, which have turning angles usually approaching 180°, are statistically analyzed from 1949 to 2011 over the western North Pacific Ocean. The typical large-scale circulation patterns of SRTCs are investigated using reanalysis data and dynamical composite analysis. Results show that turnings mainly occur in low latitudes between 10°N and 20°N,and mainly west of 135°E. The majority of SRTCs reach their peak intensity at, or slightly before, the turning time and subsequently decrease at some variable rate. Specifically, SRTCs are divided into four types, each containing two groups（*** groups in total） in terms of the moving-direction changes. The moving speed of all SRTC types except the south–north type decreases to its lowest during the 24 h, corresponding to a significant reduction in the primary steering *** to the analysis of the 13 typical flow patterns found in this study, we suggest that sudden track changes are caused by the reversal steering flow. The original balance of the background flow patterns are broken up by new systems, e.g. binary TCs or dispersion-induced anticyclones. Additionally, sudden track changes are often due to double ridge variations of the subtropical high or weakened/strengthened high pressure in the east and west, respectively.

关键词： tropical cyclone suddenly reversed turning statistical analysis steering flow

Potential Vorticity and the PV Perspective

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Advances in Atmospheric Sciences 2015年第1期32卷 2-9页

作者： Brian HOSKINS Department of meteorology University of Reading Grantham Institute for Climate Change Imperial College London

This paper highlights some theoretical aspects of potential vorticity（PV） and discusses some of the insights the PV perspective has given us. The topics covered include the nature of PV, its controlling role in the symmetric stability of the atmosphere, its inversion to give the flow field, Rossby waves and their coupling to give baroclinic instability, PV and midlatitude weather systems and, finally, insights into tropical motions.

关键词： circulation stability Rossby waves tropopause

Assessment of the three representative empirical models for zenith tropospheric delay(ZTD)using the CMONOC data

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Geodesy and Geodynamics 2024年第5期15卷 488-494页

作者： Debao Yuan Jian Li Yifan Yao Fei Yang Yingying Wang Ran Chen Tairan Xu college of Geoscience and Surveying Engineering China University of Mining and Technology-BeijingBeijing100083China Hubei Luojia Laboratory Wuhan430079China

The precise correction of atmospheric zenith tropospheric delay(ZTD)is significant for the Global Navigation Satellite System(GNSS)performance regarding positioning accuracy and convergence *** the past decades,many empirical ZTD models based on whether the gridded or scattered ZTD products have been proposed and widely used in the GNSS positioning *** there is no comprehensive evaluation of these models for the whole China region,which features complicated topography and *** this study,we completely assess the typical empirical models,the IGGtropSH model(gridded,non-meteorology),the SHAtropE model(scattered,non-meteorology),and the GPT3 model(gridded,meteorology)using the Crustal Movement Observation Network of China(CMONOC)*** general,the results show that the three models share consistent performance with RMSE/bias of 37.45/1.63,37.13/2.20,and 38.27/1.34 mm for the GPT3,SHAtropE and IGGtropSH model,***,the models had a distinct performance regarding geographical distribution,elevation,seasonal variations,and daily *** the southeastern region of China,RMSE values are around 50 mm,which are much higher than that in the western region,approximately 20 *** SHAtropE model exhibits better performance for areas with large variations in *** GPT3 model and the IGGtropSH model are more stable across different months,and the SHAtropE model based on the GNSS data exhibits superior performance across various UTC epochs.

关键词： GNSS Zenith tropospheric delay Empirical ZTD model CMONOC data

Accelerated anaerobic dechlorination of DDT in slurry with Hydragric Acrisols using citric acid and anthraquinone-2,6-disulfonate(AQDS)

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Journal of Environmental Sciences 2015年第12期27卷 87-94页

作者： Cuiying Liu Xianghua Xu Jianling Fan Jiangsu Key Laboratory of Agricultural meteorology College of Applied MeteorologyNanjing University of Information Science and Technology State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of Sciences

The application of electron donor and electron shuttle substances has a vital influence on electron transfer,thus may affect the reductive dechlorination of 1,1,1-trichoro-2,2-bis（p-chlorophenyl）ethane（DDT） in anaerobic reaction *** evaluate the roles of citric acid and anthraquinone-2,6-disulfonate（AQDS） in accelerating the reductive dechlorination of DDT in Hydragric Acrisols that contain abundant iron oxide,a batch anaerobic incubation experiment was conducted in a slurry system with four treatments of（1） control,（2） citric acid,（3） AQDS,and（4） citric acid ＋ *** showed that DDT residues decreased by 78.93%-92.11% of the initial quantities after 20 days of incubation,and 1,1-dichloro-2,2-bis（4-chlorophenyl）-ethane（DDD） was the dominant *** application of citric acid accelerated DDT dechlorination slightly in the first 8 days,while the methanogenesis rate increased quickly,and then the acceleration effect improved after the 8th day while the methanogenesis rate *** amendment by AQDS decreased the Eh value of the reaction system and accelerated microbial reduction of Fe（III） oxides to generate Fe（II）,which was an efficient electron donor,thus enhancing the reductive dechlorination rate of *** addition of citric acid ＋ AQDS was most efficient in stimulating DDT dechlorination,but no significant interaction between citric acid and AQDS on DDT dechlorination was *** results will be of great significance for developing an efficient in situ remediation strategy for DDT-contaminated sites.

关键词： 1,1,1-Trichoro-2,2-bis(p-chlorophenyl)ethane (DDT) Anthraquinone-2,6-disulfonate (AQDS) Electron donor Reductive dechlorination Soil

Tracking Surface Cyclones with Moist Potential Vorticity

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Advances in Atmospheric Sciences 2004年第5期21卷 830-835页

作者： Zuohao CAO Da-Lin ZHANG Meteorological Service of Canada Ontario Canada Department of Meteorology University of Maryland College Park Maryland

Surface cyclone tracks are investigated in the context of moist potential vorticity (MPV). A prognostic equation of surface absolute vorticity is derived which provides a basis for using negative MPV (NMPV) in the troposphere as an alternative approach to track surface cyclones. An observed case study of explosive lee cyclogenesis is performed to test the e?ectiveness of the MPV approach. It is shown that when a surface cyclone signal is absent due to the blocking of the Rocky Mountains, the surface cyclone can be well identi?ed by tracing the peak NMPV.

关键词： cyclone track moist potential vorticity lee cyclogenesis

Investigation of Mesoscale Available Potential Energy Spectra in a Simulated Tropical Cyclone

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Journal of Meteorological Research 2019年第6期33卷 1098-1112页

作者： Yuan WANG Lifeng ZHANG Jun PENG Yun ZHANG Tongfeng WEI college of meteorology and Oceanography National University of Defense TechnologyNanjing 211101 meteorology and Space Weather Monitoring and Warning Center China Xi’an Satellite Control CenterXi’an 710000

We investigated the moist mesoscale available potential energy(APE)spectra and corresponding spectral budgets of an idealized tropical cyclone(TC).The APE is defined with respect to a dry air mass using a modified potential *** wavelengths below 500 km,the mesoscale APE spectra show a consistent quasi-linear shape and a–5/3 spectral slope in the troposphere and lower stratosphere during the mature period of the *** spectral APE budget in the troposphere is dominated by diabatic and energy conversion *** mesoscale APE is forcefully injected by the diabatic effect and immediately partially converted to other forms of energy by the buoyancy *** diabatic effect contains a positive contribution from the heating effect and a negative contribution from the dehumidifying effect,which weakens the heating effect by about 16%.The energy conversion tends toward the horizontal kinetic energy at larger scales and toward the gravitational potential energy of the total moist species at smaller *** the lower stratosphere,the mesoscale APE is primarily deposited by the three-dimensional divergent effect and removed by nonlinear interactions;however,the effect of the energy conversion is *** lower troposphere and lower stratosphere are governed by clear downscale and upscale APE cascades,respectively,whereas the mid-and upper tropospheric mesoscale APE spectra undergo more complex cascade processes.

关键词： energy spectra available potential energy moist atmosphere tropical cyclone

Three-dimensional structure of an observed cyclonic mesoscale eddy in the Northwest Pacific and its assimilation experiment

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Acta Oceanologica Sinica 2021年第5期40卷 1-19页

作者： Jun Dai Huizan Wang Weimin Zhang Pinqiang Wang Tengling Luo college of meteorology and Oceanography National University of Defense TechnologyChangsha 410073China

Mesoscale eddies play an important role in modulating the ocean *** previous studies on the threedimensional structure of mesoscale eddies were mainly based on composite analysis,and there are few targeted observations for individual eddies.A cyclonic eddy surveyed during an oceanographic cruise in the Northwest Pacific Ocean is investigated in this *** three-dimensional structure of this cyclonic eddy is revealed by observations and simulated by the four-dimensional variational data assimilation(4 DVAR)system combined with the Regional Ocean Modeling *** observation and assimilation results together present the characteristics of the cyclonic *** cold eddy has an obvious dual-core structure of temperature *** core is at 50–150 m and another is at 300–550 m,which both have the average temperature anomaly of approximately-3.5℃.The salinity anomaly core is between 250 m and 500 m,which is *** horizontal velocity structure is axis-asymmetric and it is enhanced on the eastern side of the cold *** the assimilation experiment,sea level anomaly,sea surface temperature,and in situ measurements are assimilated into the system,and the results of assimilation are close to the *** on the high-resolution assimilation output results,the study also diagnoses the vertical velocity in the mesoscale eddy,which reaches the maximum of approximately 10 m/*** larger vertical velocity is found to be distributed in the range of 0.5 to 1 time of the normalized radius of the *** validation of the simulation result shows that the 4 DVAR method is effective to reconstruct the three-dimensional structure of mesoscale eddy and the research is an application to study the mesoscale eddy in the Northwest Pacific by combining observation and assimilation methods.

关键词： mesoscale eddy three-dimensional structure 4DVAR assimilation vertical velocity