Radar-based Characteristics and Formation Environment of Supercells in the Landfalling Typhoon Mujigae in 2015     

Lanqiang BAI  Zhiyong MENG  Ruilin ZHOU  Guixing CHEN  Naigeng WU  Wai-Kin WONG 《大气科学进展》2022,39(5):802-818

This study presents the radar-based characteristics and formation environment of supercells spawned by the tornadic landfalling Typhoon Mujigae(2015)in October 2015.More than 100 supercells were identified within a 24-hour period around the time of the typhoon’s landfall,of which three were tornadic with a rotational intensity clearly stronger than those of non-tornadic supercells.The identified supercells were concentrated within a relatively small area in the northeast quadrant beyond 140 km from the typhoon center.These supercells were found more likely to form over flat topography and were difficult to maintain in mountainous regions.During the study period,more supercells formed offshore than onshore.The mesocyclones of the identified supercells were characterized by a small diameter generally less than 5 km and a shallow depth generally less than 4 km above ground level.An environmental analysis revealed that the northeast quadrant had the most favorable conditions for the genesis of supercell in this typhoon case.The nondimensional supercell composite parameter(SCP)and entraining-SCP(E-SCP)were effective in separating supercell from non-supercell environment.Even though the atmosphere in the typhoon’s northeast quadrant was characterized by an E-SCP/SCP value supportive of supercell organization,orography was an impeditive factor for the supercell development.These findings support the use of traditional parameters obtained from midlatitude supercells to assess the supercell potential in a tropical cyclone envelope.  相似文献   

A statistical comparison of the CO₂ measurements at Cape St. James and Station "P", Canada     

K. HIGUCHI  V. HUDEC  N. B. A. TRIVETT  C. W. YUEN  D. CHAN  C. S. WONG 《Tellus. Series B, Chemical and physical meteorology》1995,47(1-2):4-16

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SEDIMENTS OF THE NORTH CHINA RIVERS AND THEIR GEOLOGICAL SIGNIFICANCE or A QUANTITATIVE STUDY OF THE PHENOMENA OF EROSION AND DEPOSITION IN NORTH CHINA     

翁文灝 《地质学报》1931,(1)

Ⅰ. SILT OF THE PRINCIPAL RIVERS IN NORTH CHINA. Early observations of the Huangho silt: —Although much has been said about the heavy silt burden of the Yellow River, yet exact data are very scanty  相似文献   

THE SEARCH FOR EARLY MAN IN CHINA     

W.H.WONG 《地质学报》1927,(Z1)

The first indication of the existence of early man in North Chinawas announced by Prof. Max Schlosser of Munich, Germany, who in hiswork "Die fossilen Saugethiere Chinas" in 1903 briefly described a posteriormolar tooth of Homo? or Anthropoid? gen. et sp. undetermined. The possibilityof its being Tertiary was suggested. The material was bought in Peking.  相似文献   

A model study of influence of circulation on the pollutant transport in the Zhujiang River Estuary and adjacent coastal waters   总被引：1，自引：1，他引：1  

WONG Lai Ah  GUAN Weibing  CHEN Jay-Chung  SU Jilan 《海洋学报(英文版)》2004,23(2):225-237

A tracer model with random diffusion coupled to the hydrodynamic model for the Zhujiang River Estuary (Pearl River Estuary, PRE) is to examine the effect of circulations on the transport of completely conservative pollutants. It is focused on answering the following questions: (1) What role does the estuarine plume front in the winter play in affecting the pollutants transport and its distribution in the PRE? (2) What effect do the coastal currents driven by the monsoon have on the pollutants transport? The tracer experiment results show that: (1) the pollutant transport paths strongly depend on the circulation structures and plume frontal dynamics of the PRE and coastal waters; (2) during the summer when a southwesterly monsoon prevails, the pollutants from the four easterly river inlets and those from the bottom layer of offshore stations will greatly influence the water quality in Hong Kong waters, however, the pollutants released from the four westerly river-inlets will seldom affect the water quality of Hong Kong waters due to their transport away from Hong Kong; (3) during the winter when a northeasterly monsoon prevails, all pollutants released from the eight river gates will be laterally transported seaward inside the estuary and transport westward in the coastal waters along the river plume frontal zone. However, pollutants released from the surface layer of offshore stations near or east of the Dangan Channel will be carried into the coastal waters of Hong Kong by the landward component of the westward coastal current driven by the winter northeasterly monsoon. But the pollutants from the bottom layer of the offshore stations will be carried away from the offshore by the bottom flow driven by the northeasterly monsoon. This implies that only surface-released matter from offshore stations will affect the water quality of the coastal waters around Hong Kong during the winter when a northeasterly monsoon prevails.  相似文献   

Use of artificial flood events to demonstrate the invalidity of simple mixing models     

TOMMY S. W. WONG 《水文科学杂志》2013,58(5):833-837

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Influence of upstream inflow on wave celerity and time to equilibrium on an overland plane     

TOMMY S. W. WONG 《水文科学杂志》2013,58(2):195-205

Abstract

Based on the kinematic wave equations, formulae for the wave celerity along an overland plane subject to uniform rainfall excess and with a constant upstream inflow together with the corresponding average wave celerity and time to equilibrium for the entire plane are derived. The formulae are further developed in terms of both the Darcy-Weisbach resistance coefficient and the Manning resistance coefficient. By comparing the wave celerities, the average wave celerities and the time to equilibrium for planes with and without upstream inflow show that the upstream inflow causes the wave celerity and the average wave celerity to be faster and the times to equilibrium to be shorter. The effect of upstream inflow is greater with increasing inflow, but the marginal effect decreases with increasing inflow. The effect is greatest for laminar flow and least for turbulent flow. For the wave celerity, the effect is also greatest at the upstream end of the plane and least at the downstream end of the plane.  相似文献   

An analytical study on the second-order resonance system of tide in an ideal partially-enclosed bay     

WONG Lai Ah  DONG Lixian  CHEN Jay Chung  SU Jilan 《海洋学报(英文版)》2005,24(5):1-13

In the numerical studies of a real tide M4 resonance system, the Xiangshan Port which is a partially-closed bay, Dong et al. [1999. Acta Oceanologica Sinica, 21 （3）： 1-6] found the interesting phenomenon that the advection plays an important role in inhibiting the growth of the amplitude of the tidal second-order resonance response （M4）. This result is contrary to the general traditional ideas for a non-resonance system. How this phenomenon is interpreted and what internal mechanism is behind the phenomenon are the main focuses of this study. The followings are examined： （1） the dynamic features of a second-order resonance system of tide; （2） the dominating factors on the second-order resonance responses; （3） the effects of both the friction and the advection on the second-order resonance responses; and （4） their roles in dominating the second-order resonance response and internal mechanisms by using the analytical methods. The respective results show that： （1） Both the bottom friction and the advection play significant roles in dominating the magnitude of the amplitude of the second-order resonance responses; （2） the effect of the friction on the second-order resonance response depends on the distribution ratio of the work-done of the system to friction force exhausted into between the damping of the first-order system and the inner excitation of the second-order system; （3） the advection plays a positive role in increasing the amplitude of the second-order non-resonance response in the second order non-resonance of tide; （4） in a second-order resonance system of tide, the effect of the advection may be either to increase or to decrease the amplitudes of the second-order resonance responses of tide, which depends on the distribution ratio mentioned above.  相似文献   

Climatic effect on DMS producers in the NE sub-Arctic Pacific: ENSO on the upper ocean     

CHI-SHING WONG  SHAU-KING EMMY WONG  ANGELICA PEÑA  MAURICE LEVASSEUR 《Tellus. Series B, Chemical and physical meteorology》2006,58(4):319-326

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Application of Multi-Scale Tracking Radar Echoes Scheme in Quantitative Precipitation Nowcasting     

WANG Gaili  WONG Waikin  LIU Liping  WANG Hongyan 《大气科学进展》2013,30(2):448-460

A new radar echo tracking algorithm known as multi-scale tracking radar echoes by cross-correlation(MTREC) was developed in this study to analyze movements of radar echoes at different spatial scales.Movement of radar echoes,particularly associated with convective storms,exhibits different characteristics at various spatial scales as a result of complex interactions among meteorological systems leading to the formation of convective storms.For the null echo region,the usual correlation technique produces zero or a very small magnitude of motion vectors.To mitigate these constraints,MTREC uses the tracking radar echoes by correlation(TREC) technique with a large "box" to determine the systematic movement driven by steering wind,and MTREC applies the TREC technique with a small "box" to estimate small-scale internal motion vectors.Eventually,the MTREC vectors are obtained by synthesizing the systematic motion and the small-scale internal motion.Performance of the MTREC technique was compared with TREC technique using case studies:the Khanun typhoon on 11 September 2005 observed by Wenzhou radar and a squall-line system on 23 June 2011 detected by Beijing radar.The results demonstrate that more spatially smoothed and continuous vector fields can be generated by the MTREC technique,which leads to improvements in tracking the entire radar reflectivity pattern.The new multi-scale tracking scheme was applied to study its impact on the performance of quantitative precipitation nowcasting.The location and intensity of heavy precipitation at a 1-h lead time was more consistent with quantitative precipitation estimates using radar and rain gauges.  相似文献