1. Storm Top Processes Related to the Cross ‐ Tropopause Transport Potential Applications of START08 Data Pao K. Wang Department of Atmospheric and Oceanic Sciences University of Wisconsin-Madison March 4, 2009 START08 Workshop, NCAR

2. Storm top processes Wave motions and instability on top of thunderstorms may contribute significantly to the cross-tropopause transport of water vapor and possibly other trace chemicals. Currently the details of these processes are unclear. Both satellite observations and cloud resolving model simulations show some interesting possibilities. START08 data may be very useful in shedding lights on these processes

3. Strom top plumes Satellite observation of middle latitude deep convective storms plume Anvil Storms over Balearic Islands

4. GOES visible images — nearly every active cell is associated with plumes

5. 13 July 2004 MODIS Aqua band 1, Northern Illinois MODIS examples MODIS – Aqua, 03 June 2003, 19:28 UTC, band 1 Louisiana

7. Cloud model simulation of the plume phenomenon WISCDYMM (Wisconsin Dynamical/Microphysical Model) Type – 3D, nonhydrostatic, time-dependent prognostic model Type – 3D, nonhydrostatic, time-dependent prognostic model Dynamics – quasi-compressible primitive equations Dynamics – quasi-compressible primitive equations Microphysics – 5 hydrometeor types (cloud drops, cloud ice, rain drops, snow, graupel-hail), parameterized or bin-category Microphysics – 5 hydrometeor types (cloud drops, cloud ice, rain drops, snow, graupel-hail), parameterized or bin-category BC – Top: Rayleigh layer, Bottom: nonslip, lateral: radiation BC – Top: Rayleigh layer, Bottom: nonslip, lateral: radiation Resolution and Domain – adjustable. ( 1 x 1 x 0.2 km here) Resolution and Domain – adjustable. ( 1 x 1 x 0.2 km here) Initialization – surface temperature and humidity perturbations. Initialization – surface temperature and humidity perturbations.

8. 2 AUG 1981 CCOPE Supercell in Montana

10. Instability and Wave Breaking Convection-induced instability and gravity wave breaking at the storm top send H 2 O through the tropopause to enter the stratosphere. Overshooting top plumes Wave breaking – Jumping cirrus Wang (2007)

11. Fujita’s jumping cirrus “ One of the most striking features seen repeatedly above the anvil top is the formation of cirrus cloud which jumps upward from behind the overshooting dome as it collapses violently into the anvil cloud ”. (Fujita, 1982)

12. WISCDYMM simulation of CCOPE Supercell

13. Fujita (1982, 1989) observed jumping cirrus above severe storms – they are also due to wave breaking Photo courtesy of Martin Setvak Modeled CCOPE storm cloud top Similar shape, size, orientation and occur at similar relative location Overshooting top jumping cirrus From: Wang (2004, GRL)

14. Jumping cirrus taken by webcam in Zurich (courtesy of Willi Schmid, ETH, Zurich)

15. Would such cross-tropopause transport occur in a weak or no wind shear environment ? This may happen more often in tropics as wind shears are usually weaker This may happen more often in tropics as wind shears are usually weaker Model simulation shows that, instead of plumes, a patch of moisture may break away from the storm due to Rayleigh-Taylor instability and form a pancake-shaped cloud on top of the storm. Model simulation shows that, instead of plumes, a patch of moisture may break away from the storm due to Rayleigh-Taylor instability and form a pancake-shaped cloud on top of the storm. Such pancake clouds are actually observed recently. Such pancake clouds are actually observed recently.

16. Pancake on top of the anvil Simulated CCOPE supercell without wind shear and winds

18. A pancake cloud above a Cb over Taiwan (courtesy of Po-Hsiung Lin)

19. Satellite observation (courtesy of Martin Setvak)

20. Tiwi Islands, Australia (12°S, 130°E) without wind (Lane and Reeder, 2001; based on Keenan et al., 2000; )

23. Cb with multiple anvil layers (near Taiwan)

24. START08 Are there cases with strong and weak wind shears? Do vertical water vapor or ice crystal profiles show distinct multiple maxima? How about other tracers? In-situ collection of ice crystal samples?