Anvil Generation in Relation to Cloud System Water Budget: TWP-ICE Case of January 2006 Jasmine Cetrone and Robert Houze University of Washington 8 November 2006, ARM Cloud Processes Working Group, Annapolis, MD

Water Budget of an MCS

Water Budget Equations Convective region water budget equation R c = ε c C cu E cd = αC cu A c = βC cu C T = ηC cu ε c +α+β+η=1

Water Budget Equations Stratiform water budget equation Rain not simply related to condensation R s = ε s (C su +C T ) E sd = a(C su +C T ) A s = b(C su +C T ) ε s +a+b=1

* E cd C cu C su E sd CTCT AcAc AsAs HEIGHT MIXED ANVIL RcRc RsRs STRATIFORMCONV.ANVIL E ce XAXA E se XSXS XCXC  Z A ) I  X A ) M  X A ) I * * * * * * * * * ICE ANVIL  Z A ) M * * * PRECIPITATING CLOUD ANVIL RcRc RsRs A c + A s * * * * * * * * * * ZAZA * * * XAXA XSXS XCXC  X A ) M  X A ) I HEIGHT Simplified Water Budget Model

19-20 January MCS

Finding anvil amounts from water budget equations Assume portion of cloud system passing over radar was representative of whole system (not true) Compute total convective and stratiform rain amounts from C-Pol radar (in radar domain) Use a range of assumed values of the water budget parameters ε c,α,η,ε s,a (from Houze and Cheng 1981) Compute A c + A s

Results using water budget R c = x kg, R s = x kg αaεcεc A c + A s x kg x kg x kg x kg x kg x kg Realistic Values, acc. to Houze and Cheng 1981

19-20 January MCS dBZ Convective Stratiform Anvil Cloud Radar

Finding anvil amounts from MMCR and C-Pol Find a relationship between cloud thickness and IWP (MMCR) Compute the average area and thickness of anvil clouds in radar range using C-Pol Calculate the amount of anvil water/ice (A c + A s ) that is in range of C-Pol IWP=0.026∆z R 2 = IWP [kg/m 2 ] Thickness [km]  A c + A s = x kg We’re only getting about 10% of the anvil calculated by the water budget equations MMCR

Why such a difference?? 1. The CPol will miss some anvil because of it’s lower sensitivity

Why such a difference?? 2. Above about 8-km, the winds were easterly, shearing much of the anvil to the west instead of it trailing behind the system (i.e. out of CPol’s range)

Future Improvements Use dual-Doppler velocities, cloud radar, and sounding data to compute other values (CT, Ccu, Ecd, Csu, Esd) to calculate the water budget parameters Use satellite data to extend water budget to the whole system, rather than just radar area Use model simulations to help close the water budget Connect water budget to the TRMM PR overpass Find other cases  JASMINE, KWAJEX

JASMINE Ship Radar Data TRMM Precipitation Radar Swath 23 May LST JASMINE Bay of Bengal India

Cloud Radar Cloud radar on ship shows anvil Cloud Radar TRMM PR Also: Scanning radar and ship soundings

KWAJEX TRMMTRMM Scanning C- and S-band Doppler radarsScanning C- and S-band Doppler radars Vertically Pointing S-band radarVertically Pointing S-band radar Sounding NetSounding Net

Thanks!

KWAJEX