E. C. Meyers, G. M. McFarquhar, B. F. Jewett, S. W. NesbittUniversity of Illinois at Urbana-Champaign

11 May 2010

Vertical Velocity and Microphysical Distributions Related to the Rapid

Intensification of Hurricane Dennis (2005)

E N

WS

Image Science and Analysis Laboratory, NASA-Johnson Space Center. "The Gateway to Astronaut Photography of Earth.”http://eol.jsc.nasa.gov/scripts/sseop/photo.pl?mission=ISS011&roll=E&frame=10221

E

NW

SImage Science and Analysis Laboratory, NASA-Johnson Space Center. "The Gateway to Astronaut Photography of Earth.”http://eol.jsc.nasa.gov/scripts/sseop/photo.pl?mission=ISS011&roll=E&frame=10216

Guiding Questions• How do such isolated, inner-core, most-intense

vertical velocities (i.e., convective bursts) cause and/or respond to rapid intensification (RI) of tropical cyclones?

Guiding Questions• How do such isolated, inner-core, most-intense

vertical velocities (i.e., convective bursts) cause and/or respond to rapid intensification (RI) of tropical cyclones?

• What statistics can be gathered from a high-resolution simulation regarding convective bursts’ distributions, magnitudes, vertical structures, durations, proximities to the vortex center, and trends as precursors to RI?

• Limited understanding of how RI may relate to convective bursts– 3-D structure– Timing– Distributions of latent heat

Motivation

• Limited understanding of how RI may relate to convective bursts– 3-D structure– Timing– Distributions of latent heat

• Need to statistically characterize the morphology of these isolated, intense vertical velocities and associated microphysics within observational voids

Motivation

WRF Configuration Horizontal…

27-km

9-km3-km 1-km

d01

d02d03

d04

736

784

WRF Configuration Vertical…

Dennis Track

00Z 06 July 200500Z 07 July 2005

00Z 08 July 2005

*10 min

*

Intensity

*10 min

*

Intensity

-19 hPa (6 h)-1

*10 min

*

Intensity

*

*

*10 min

+36 kts (6 h)-1

14:20Z-14:32Z 09 July 2005

[dBZ]

[m s-1]14:45Z-15:03Z 09 July 2005

• Guimond et al. (2010, JAS)

• Are column-confined, averaged, and low-to-mid-level interpretations valid?

Convective Bursts?

10-min

2-min

10-min

2-min

CFAD

9 hours before RI

9 hours during RI

Column Max Reflectivity

s

9 hours before RI

9 hours during RI

during – before RI

CFAD Difference

hourly 99.9th percentile w [m s-1]

• Interpretation of RI depends on:– Interval examined– ∆pmin or ∆|v10-m, max| perspective

• Discrete vertical level statistics provide better identification of convective bursts than column averages or thresholds

• Outlier (e.g., 99.9th percentile) w better indicators of RI than averages– Precursor to RI at upper levels (e.g., 14 km)– Continual broadening and convergence toward TC center

CONCLUSIONS

CONCLUSIONS, CONT’D• Outlier (e.g., 99.9th percentile) w at lower levels (e.g.,

6 km), however, increase only after onset of and during RI

• Manifested as an increase in latent heating• Precursor w have unnoticeable impact on latent

heating– Vertical structure– Thresholds for definition

• Implications of these upper-level, rapidly accelerating updrafts for RI?

Acknowledgements• AMS Graduate Fellowship, Earth Science Div. of the Science

Mission Directorate• NASA Headquarters under the NESSF Program• NASA Hurricane Science Program – Grant NNX09AB82G• NOAA/GFDL• WRF Modeling Community• TeraGrid• Seemingly endless list of students, staff, and faculty at the

University of Illinois at Urbana-Champaign and beyond

THANK YOU!Boston.com “Hurricanes, as seen from orbit”

http://www.boston.com/bigpicture/2008/09/hurricanes_as_seen_from_orbit.html

*LH, Abe

< -80

Precursor to RI?

Colin et al. (2009, Nature Geosci.)

*history interval accumulation

≤ 5> 3

> 15

≤ 0> -2

< -10

*instantaneous, @ output

*instantaneous, @ output

≤ 0> -60

< -540

> 1.0< 5.0

> 30.0< 40.0

2030Z7th

2036Z7th

2042Z7th

2048Z7th

2054Z7th

2100Z7th

Obs

erve

d on

set

of R

I

Every 6 hours from contour analysis of simulation

onset of simulated 24-hour period during which ∆pmin ≤ -42 hPa

Every 3 hours from contour analysis of simulation

onset of simulated 24-hour period during which ∆|v10-m, max contour| ≥ +30 knots

Every 6 hours from contour analysis of simulation

onset of simulated 24-hour period during which ∆|v10-m, max contour| ≥ +30 knots

Every 3 hours from contour analysis of simulation

hourly 99.9th percentile w [m s-1]

• Zhu and Zhang (2006, JAS)

• Li and Pu (2008, MWR)

Relation to Microphysics

only warm rain processes; hmmm…

LI AND PU MARCH 2008

WSM3

WSM5WSM6

Increasing inclusion of mixed-phase proc. graupel

support Wang (2002)

Rogers (2010, JAS)

Rogers (2010, JAS) MEAN, convective regions

72.9°W

71.6°W

15.6°N

16.7°N

(|V10-m| ≥ 30 knots) contoured (interval = 5 knots) in black18:00Z 06 July 2005

What About the Vertical?

> 35< 40

> 15< 20

< 364

> 372< 374

> 370< 374

> 358< 362