Title: Quadrant distribution of tropical cyclone inner-core kinematics in relation to environmental shear
1Quadrant distribution of tropical cyclone
inner-core kinematics in relation to
environmental shear
This research was supported by NASA grants
NNX12AJ82G and NNX13AG71G and NSF grant
ATM-0743180
- Jennifer C. DeHart, Robert A. Houze, Jr., and
Robert F. Rogers - AMS Tropical April 4th, 2014
2Prior Composite Studies
- Big Takeaways
- General downshear-upshear convective pattern
- No analysis of vertical dimension
- Horizontal Composites
- Rainfall (Chen et al. 2006)
- Lightning (Corbosiero and Molinari 2002, 2003)
3Vertical Structure
- Hence and Houze (2011)
- TRMM PR
- convective evolution
- BUT lack velocity
- Reasor et al. (2013)
- vertical motion consistent with previous studies
- BUT only examine mean
4Objective
- Examine the PDF of vertical velocity to determine
if it is consistent with the eyewall convective
evolution implied by the radar reflectivity
statistics
5Dataset
- 2003-2010
- 125 eyewall crossings, 39 flights, 12 hurricanes
- SHIPS deep-layer shear (850-200 hPa)
- gt 2 kts
- NOAA WP-3D Tail Radar
- Automated variational algorithm
- Gamache 1997
- Normalize horizontal dimension by RMW2km
6Eyewall Radar-derived Vertical Velocity CFAD
7Eyewall Vertical Velocity -- Anomalies
contours 2
0
-
8Conclusion 1 Confirmation of convective
evolution hypothesis
9What about outlier velocities?
- Recent studies have analyzed strong updrafts in
relation to intensity changes - how do they behave in relation to shear?
- Isolate data points where
- w gt 5 m s-1
- w lt -4 m s-1
- Investigate radial-height structure
10Intense Updrafts -- Shear
contours 5 -------------- 50
11Intense Downdrafts -- Shear
contours 5 -------------- 50
12Conclusion 2
- Intense drafts follow same pattern in relation to
shear - Strong updrafts occur more often downshear.
- Strong downdrafts are highly concentrated in the
UL quadrant.
13Frame drafts in context of w, vr
- Identify azimuth of strong drafts
- Isolate sector /- 2 degrees from azimuth
- Composite cross-sections
- Only unique data points used
- sectors of adjacent drafts used only once
14Total Eyewall
Intense Updrafts
Intense Downdrafts
15Radial Flow in left of shear quadrants
- Relationship between radial and vertical flow
- is vertical motion amplified by radial flow?
- does vertical motion induce radial flow?
- do they arise from a common cause
Intense Updrafts
Intense Downdrafts
16Conclusion 3
- Radial flow suggests different dynamical behavior
when intense updrafts and downdrafts present