Intensity change and possible unusual eye wall replacement cycle of Edouard between

14 – 15 September 2014

Ed ZipserDepartment of Atmospheric Sciences

University of Utah, Salt Lake City, UT, USAed.zipser@utah.edu

Acknowledgments: Trey Alvey, Rob Rogers, Jon Zawislak, SSEC team, and so many, many others who made HS3

possible

HS3 Science Meeting Tuesday May 5, 2015

At least 2 drops ~ 21 UTC with sfc pressure < 970 mb and wind > 40 m/s

reGPM Overpass of Edouard

GPM Cross-Section through Edouard’s eye (Ku dBZ and Tb at 37, 85, 183+/-7 GHz)

[Eye radius ~ 25 km at low levels]

From Chuntao Liu’s PF database

P3 Lower FuselageImages 14 Sept.

Inner circle is estimated RMW(25 km) from tail radarOuter black lineIs 50 km.

850-200 hPashear vector

N

P3 Lower FuselageImages 15 Sept.

Circle is estimated RMW(45 km) from tail radar

Box (1 X 1°) is samescale as on 14 Sept.

N

850-200 hPashear vector

15th 15 UTC14th 16 UTC

16th 20 UTC

16th 19 UTC

14th 15 UTC

15th 16 UTC

85-91 GHzPCT

85-91 GHz

P3exit

GHenter

EWRC?

So, what can the GH Flight of 14-15 September tell us about Edouard’s intensity change and possible eyewall

replacement cycle?

• Interesting changes in distribution of deep convection started during the 3 hours between departure of the P-3 and the arrival of the GH.

• Convective bursts close to the center left of shear evolved quickly into more symmetric coverage, and at a larger radius.

• Dropsondes should reveal both large scale humidity distribution and small scale changes in the inner core.

• S-HIS may supplement occasional satellite coverage and give profiles in the eye center that the dropsondes just missed.

Passive Microwave Tb at time of first GH eye crossing (N-S)Deep convection at r=25 km (west), 60 km (east). Start of EWRC?

91 GHz PCT 37 GHz (H)

100 km

200 km

Location and trajectory of AVAPS drops near Edouard N-S eye crossing at 2102 Z on 14 Sept

(Note: SHIS shows GH over eye at 2102 Z; also at 0034 Z)

IR Tb < 200K

2100 Z release N of eye, gets into N wall 2103 Z release SE of eye. enters eye

-48° -45°

-2° +2°

COOL! WARM!

Brief Summary

• In spite of a great deal of data from 2 P-3 flights and an excellent GH flight, Edouard’s inner core evolution between 14-15 Sept. is complex and not easily understood.

• The RMW expands from 25 – 45 km during the GH flight but there is little indication of a conventional EWRC.

• A quick look at the dropsondes indicates both high and low theta-e air in different portions of the eyewall. (Why?)

• Challenge: Can numerical simulations shed light on the reasons for the convective evolution, eyewall radius and intensity changes between 14-16 September?

Upshear – Downshear cross section

Upshear – Downshear cross section

Upshear – Downshear cross section

Upshear – Downshear cross section

Upshear – Downshear cross section

Upshear – Downshear cross section

Upshear – Downshear cross section