 |
| Titel |
The genesis of Typhoon Nuri as observed during the Tropical Cyclone Structure 2008 (TCS-08) field experiment – Part 3: Dynamics of low-level spin-up during the genesis |
| VerfasserIn |
L. L. Lussier III, M. T. Montgomery, M. M. Bell |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 14, no. 16 ; Nr. 14, no. 16 (2014-08-27), S.8795-8812 |
| Datensatznummer |
250118984
|
| Publikation (Nr.) |
 copernicus.org/acp-14-8795-2014.pdf |
|
|
|
|
|
| Zusammenfassung |
| Aircraft reconnaissance data collected during the Tropical Cyclone Structure
2008 field campaign are used to examine further kinematical, dynamical, and
thermodynamical aspects of the genesis of Typhoon Nuri. Data from the first
two missions into the pre-Nuri disturbance document the transition from a
tropical wave to a tropical depression. Dropwindsonde-derived tangential
wind profiles at several radii from the low-level circulation center
indicate that the magnitude of low-level circulation increases and that
the corresponding tangential velocity maximum moves inward from the first to
second reconnaissance mission. To compliment these findings, a
three-dimensional variational analysis incorporating both dropwindsonde
and aircraft Doppler radar data is conducted. These data are used to perform
circulation tendency calculations at multiple distances from the low-level
circulation center. The results demonstrate a net spin-up of the
system-scale circulation in the low levels near the center and in the
outer regions of the recirculating Kelvin cat's eye circulation. In these
regions, the spin-up tendency due to the influx of cyclonic absolute
vorticity exceeds the frictional spin-down tendency for both Nuri missions.
The system-scale spin-up is found to be accompanied by areas of
low-level vorticity concentration through vortex-tube stretching
associated with cumulus convection. The areal coverage and intensity of
these high-vorticity regions increase between the first and second Nuri missions.
The findings of this study are consistent in some respects to the Nuri
observational analysis carried out by Raymond and López-Carrillo (2011),
but differ in their suggested key results and related scientific implications
that the pre-Nuri disturbance was spinning down in the planetary boundary
layer on the first day of observations. The findings herein strongly support
a recent tropical cyclogenesis model positing that the Kelvin cat's eye
circulation of the parent wave-like disturbance provides a favorable
environment for convective vorticity organization and low-level spin-up
on the mesoscale. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|