Tropical cyclones over the Arabian Sea in the pre-monsoon season (May–June) have intensified since 1997 (ref. 1, Fig. 1a) owing to significant reductions in storm-ambient vertical wind shear (VWS) in the troposphere; these reductions have decreased on average by about 3m s from the pre-1997 epoch (1979–1997) to the recent epoch (1998–2010). The authors attribute the reduction of premonsoon VWS ...

a Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung 80424, Taiwan b Department of Oceanography, National Sun Yat-sen University, Kaohsiung 80424, Taiwan c Naval Ocean Analysis and Prediction Laboratory, Naval Postgraduate School, Monterey, CA 93943, USA d Institute of Maritime Information and Technology, National Kaohsiung Marine University, Kaohsiung ...

The objective is to investigate the physical processes that occur as a tropical cyclone interacts with the environment such that intensity and structure changes occur. Specific interactions being studied are with baroclinic environments in the midlatitudes during extratropical transition. During extratropical transition, radical changes to the storm structure occur as vertical wind shear and in...

Tropical cyclone intensity change remains a forecasting challenge with important implications for such vulnerable areas as the U.S. coast along the Gulf of Mexico. Analysis of 1979–2008 Gulf tropical cyclones during their final two days before U.S. landfall identifies patterns of behavior that are of interest to operational forecasters and researchers. Tropical storms and depressions strengthen...

In final form 31 October 2006 ©2007 American Meteorological Society ropical cyclones (TCs) are among the most destructive of natural disasters. The statistics of TC occurrence and intensity are influenced by variations in the large-scale climate, but many aspects of this influence are poorly understood. Even less is known about the influence of tropical cyclones on the large-scale climate. Thes...

[1] This paper explores the impact of the physical parameterization suite on the evolution of an idealized tropical cyclone within the National Center for Atmospheric Research’s (NCAR) Community Atmosphere Model (CAM). The CAM versions 3.1 and 4 are used to study the development of an initially weak vortex in an idealized environment over a 10‐day simulation period within an aqua‐planet setup. ...

Passive microwave radiometers have a strong heritage of instruments: the Special Sensor Microwave Imager (SSM/I), the Tropical Rainfall Mapping Mission (TRMM) Microwave Imager (TMI), the Advanced Microwave Scanning Radiometer–Earth Observing (AMSR-E) and the Special Sensor Microwave Imager/Sounder (SSMI/S). These instruments measure vertically and horizontally polarized brightness temperatures ...

Surface measurements in tropical cyclones (TCs) are difficult to obtain and only microwave sensors below 15 Ghz can penetrate the deep convective clouds surrounding the areas where surface winds are the largest (Quilfen et al., 2007). These kind of measurements are crucial to complement the Dvorak TC intensity analysis as obtained from infrared/visible measurements (Velden and Coauthors, 2006)....

The use of QuikSCAT data for wind retrievals of tropical cyclones is described. The evidence of QuikSCAT 0 dependence on wind direction for 30-m/s wind speeds is presented. The QuikSCAT 0 show a peak-to-peak wind direction modulation of 1 dB at 35-m/s wind speed, and the amplitude of modulation decreases with increasing wind speed. The decreasing directional sensitivity to wind speed agrees wel...

[1] The forced secondary circulation (FSC) by the vertical shear of horizontal winds is isolated from the latent heating and friction FSCs associated with a model-simulated hurricane vortex. This is achieved by use of a newly developed potential vorticity inversion and quasi-balanced vertical motion equations system. Results show that latent heating forces intense updrafts in the eyewall and sl...