Download presentation
Presentation is loading. Please wait.
1
Thermodynamic Structure of Tropical Cyclones From Aircraft Reconnaissance Kay Shelton University at Albany/SUNY, Albany, New York
2
US Air Force reconnaissance flights. –Archive maintained by John Knaff (CIRA). 1995-2003, 77 storms 619 flights. Equivalent potential temperature e. –Bolton (1980). Case-study: Bret, 1999. –Comparison of e and windspeed through storm evolution from tropical depression through to category 4 hurricane. Composite of all storms. –Data every 30s, averaged into 20km radial bins –(>5 points per bin to be included) –Categorised average e profiles by level and intensity. DATA AND METHODOLOGY
3
Instrument wetting errors (IWE). –Eastin et al. (2002).LIMITATION Adapted from Eastin et al. 2002b IWE minimised away from eyewall. In eyewall, maximum mean error < 3K. Removal of IWE acts to move maximum radial gradient towards outer edge of eyewall. Errors may be larger for individual cases.
4
Hurricane Bret, 1999. –Organised to TD at 18Z on 18 th August, in Bay of Campeche. –Bret strengthened to category 4, then decreased to category 3 prior to landfall on Padre Island, TX at 00Z on 23 rd August. –Scatter plots of e and windspeed in six flights will be shown. CASE STUDY
5
<500m TD-TS TS <500m ee Windspeed
6
TS H1-H2 ~850hPa 37.5km ee Windspeed
7
H4 H4-H3 ~700hPa 17.8km 32.5km ee Windspeed
8
COMPOSITE Flight level must increase as storms intensify. Weaker systems have fewer flights above PBL, stronger systems have fewer flights below 700hPa. Comparison between levels at a given intensity is limited to TS and H1.
9
COMPOSITE INWARD RADIAL GRADIENT OF e - e / r ( K/100km) <500m ~850hPa ~700hPa
10
e DIFFERENCE BETWEEN 2 LEVELS TS: e (BL) – e (850hPa)H1: e (850hPa) – e (700hPa) e (K) Arrows indicate relevant tropical environment e / p (Jordan, 1958)
11
SUMMARY RADIAL TD: | e / r| ~ 0 at all radii TS: e increases first in the core (r<90km) H1-H4: | e / r| increases with intensity, within r=100km VERTICAL TS and H1: In lower troposphere convective instability increases outward. –Both profiles are close to convective neutrality near storm centre and convective instability increases outwards to their respective tropical environmental values.
Similar presentations
© 2024 SlidePlayer.com Inc.
All rights reserved.