Meeting the challenge of obtaining and interpreting observations of deep convection in tropical disturbances and hurricanes by
Meeting the challenge of obtaining and interpreting observations
of deep convection in tropical disturbances and hurricanes
Ed Zipser, Jon Zawislak, and Gabriel Susca-Lopata, University of Utah, Salt Lake City, with assistance of numerous colleagues on the GRIP and HS3 science teams, including
but not limited to Chris Velden, Gerry Heymsfield, Dan Cecil, Rob Rogers, APR-2 team …
Help in interpreting and improving the overflight criteria for the Global Hawk to maintain a safe operation, while obtaining much-needed data over and in the near-vicinity of deep convection during the remainder of HS-3.
Analyze and understand the vertical distribution of convective updrafts and downdrafts with respect to horizontal dimension, updraft magnitude, cloud dynamics and microphysics, radar reflectivity, anvil top temperature and height, overshooting tops, and associated turbulence.
MAJOR CHALLENGE: CAN REMOTE SENSING DATA SUBSTITUTE FOR IN-SITU DATA?
Example Hurricane Earl during GRIP, 28-30 August of Univ. of Wisconsin
ACHA product for a 40-minute
period during Earl’s RI. Interval
between images 6-9 minutes.
Circles identify overshooting
tops, meaning local IR Tb colder
than surrounding clouds.
Note that overshooting tops Hurricane Earl during GRIP, 28-30 August
are transient (expected)
Next: Examine evidence from
ER-2 (EDOP) overflights of
deep convection and
=>Strong evidence of buoyant
“bubbles” rising through
deep cloud systems
Chantal 2001 Hurricane Earl during GRIP, 28-30 August
Courtesy Gerry Heymsfield; EDOP data
After Hurricane Earl during GRIP, 28-30 August G.Heymsfield et al., JAS 2010; relationship between updrafts and dBZ (z) profiles
The one you’ve heard about: ER-2 overpass of Emily 2005 Hurricane Earl during GRIP, 28-30 August
Cecil et al., MWR2010
From Houze, Lee, Bell, MWR 2009
We don’t get such data any more!
• See also Houze, Lee, and Bell, MWR 2009 showing updraft of comparable size and strength
in a convective burst in a tropical depression that later became Hurricane Ophelia (2005)
• Even these exceptionally strong (for oceans) updrafts are only about 2 km across in mid-troposphere. (We have no information on their size and intensity closer to cloud top.)
• Question: Do we expect a 1-km resolution simulation to handle 2-km updrafts accurately?
• Question: Do we expect dual-Doppler retrievals from aircraft to resolve 1-2 km updrafts?
How about HIWRAP?
Comments, questions, arguments?