On the Origin of Hurricane Spiral Rain Bands

Precipitation system size, shape, location, lifetime, and motion in 16 mature and early weakening stages of typhoons around Japan was studied, using conventional radar network data. Based on these findings, precipitation systems in typhoons apart from mid-latitude frontal zones were classified into inner and outer rain shields, inner and outer rainbands, and eyewalls. Delta-shaped precipitation systems, called delta rain shields, were found to characterize typhoons approaching mid-latitude frontal zones.

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Classification of Precipitation Systems in Mature and Early Weakening Stages of Typhoons around Japan

Shimazu¹

1998

“…It is also noted that the distance of these zones from the storm center is gradually expanding with time. This is similar to the motion of spiral rain bands relative to the storm center studied by Senn and Hiser (1959).…”

Section: Analysis Of the Time Change Of Rainfall Intensitymentioning

confidence: 99%

Precipitation Bands of Typhoon Vera in 1959 (Part I)

Hamuro

Kawata

Matsuda

et al. 1969

A case study of the rainfall associated with Typhoon Vera (the Ise Bay Typhoon) in 1959 is made. From an inspection of hourly precipitation charts, one gets an imprestion that the rainfall amount with the typhoon is solely dependent upon the orographic elect.However, the analysis of time changes of rainfall intensity reveals the existence of well-organized zones of alternating heavy and weak rainfall intensity surrounding the storm center. The surface pressure field also contains similar banded structure.A comparison with the radar pictures shows the correspondence of these zones to groups of radar rain bands.

“…It has been well known since the 1940's that cumulus convection in tropical cyclones is organized as an eyewall and spiral rainbands and that latent heat released by cumulus convection is the energy source of tropical cyclones (Simpson, 1947(Simpson, , 1952Palmen, 1948;Jordan, 1952Jordan, , 1958Senn and Hiser, 1959;Riehl and Malkus, 1961;Yanai, 1961). Since cumulus convection usually has to be treated implicitly in theoretical and numerical models, how to incorporate its effect into a model has been an important but difficult problem.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Surface Friction on the Mesoscale Organization of Cumulus Convection in Tropical Cyclones

Nasuno¹,

Yamasaki²

1997

In order to study the effect of surface friction on the properties of mesoscale convection which constitute the rainbands of tropical cyclones, numerical experiments are performed with an axi-symmetric non hydrostatic model. As discussed by Yamasaki (1983), when the tangential wind velocity is not very strong (10 ms-1 or less), the typical time scale of mesoscale convection is a few hours. When the tangential wind intensifies and frictional inflow becomes very significant, the lifetime of mesoscale convection becomes 11-12 hours. In contrast to the convection with time scale of a few hours, it does not decay owing to an outward shift of low-level convergence associated with the intensification of cold downdraft outflow. Its decay is caused by its inward shift due to strong frictional inflow. In this situation, rainwater falling from the cloud, which tilts outward with height at this stage, acts to prevent the low-level warm moist air from flowing into the cloud. A new mesoscale convection is formed at some distance from the old one. Structure, time evolution and the mechanism of the mesoscale convection with the longer lifetime are discussed in detail.