Understanding Atmospheric Heating in
the GPM Era
Robert Houze
University of Washington
Heating
algorithms
are
expected
to be an
important
product of
GPM
6th GPM International Planning Workshop, 6-8 November 2006, Annapolis, Maryland, USA
Relationship of Cloud Water Budgets to
Heating Profile Calculations
Total
heating
Austin and Houze 1973
Houze et al. 1980
Houze 1982, 1989
Takayabu 2002
Shige et al. 2006
Latent
heating
only
Houze 1982
PREMISE
Can also relate eddy & radiative heating profiles to
water budget to obtain
Total Heating = Latent + Eddy + Radiative
Tropical MCSs inject lots of hydrometeors into upper troposphere
Idealized life cycle of tropical MCS as proposed by Houze 1982
Contributions to Total Heating by Convective Cloud System
Conv. LH
Strat. LH
Conv. Eddy
Rad.
Strat. Eddy
Details from Houze 1982
These combine to give “top-heavy” heating profile
TOTAL HEATING
“Top
Heavy”
profile.
Includes
latent,
eddy, and
radiative
heating.
Houze 1982 idealized case
Think of the following schematic as a composite of the water
budget of an MCS over its whole life cycle
Ac
As
After Houze et al. (1980)
Ac
As


E  a C  C 
A  b C  C 
Rs   s Csu  CT
Stratiform water budget equation
Csu  CT  Rs  Esd  As
Rain not simply related to condensation
sd
s
su
su
where
s  a  b  1
T
T
Ac
Water budget parameters:
As , Rs , Csu, CT
Need to be determined empirically
Field projects, CloudSat,…
As


E  a C  C 
A  b C  C 
Rs   s Csu  CT
sd
s
su
su
T
T
where
 s  a  b  1  error
Ac
As
Convective region water budget equation
Ccu  Rc  Ecd  Ac  CT
Ac
Sum over all
cloud height
categories i
As
R   Rci
For each height category i
i
Ccu   Ccui
i
Ecd   Ecdi
i
CT   CTi
i
Ac   Aci
i
Rci   iCci
Esdi   iCci
Aci  iCci
CTi  iCci
with the constraint
 i   i   i  i  1
(each height cat.)
ZAC
Ac
As
XAC
Dimensions and hydrometeor content of anvils are
determined by the cloud dynamics and are related to the
radiative heating profiles
These also need to be determined empirically
Using empirically derived values of the water
budget parameters b and s, the stratiform
regions’ anvil mass is proportional to the
stratiform rain
As =(bRs)/s
400 hPa
K/day
200 hPa streamfunction response to CRF assumed proportional to
TRMM rain by Schumacher et al. (2004)
Summary
• Profiles of latent heating estimated by spectral methods are not
independent of eddy and radiative heating profiles.
• Latent, eddy and radiative heating are interrelated through the
water budget of the precipitating cloud system.
• Cloud water budget provides a means to establish the internal
consistency of latent and radiative heating profiles and hence
allows us to link radiative and eddy heating to latent heating
• Global patterns of heating estimated from GPM data can be
extended to include radiative and eddy heating.
• Water budget parameters will need to be determined
empirically in field studies aimed at understanding the anvil
cirrus generation, and/or in conjunction with CloudSat .
Final Thought
• Too ambitious?
• Think 15 years from now!
Thank you!
Extra Slides:
Example from TWP-ICE
Precipitation Radar
20 January 2006 0000UTC
11˚
S
12˚
S
13˚
S
130˚E
131˚E
dB
Z 6
11˚0
S5
3
4
6
12˚3
S9
3
2
2
13˚5
1
S
8
6 km 1
1
132˚E
4
20 January 2006 0900UTC
130˚E
131˚E
dB
Z 6
11˚0
S5
3
4
6
12˚3
S9
3
2
2
13˚5
1
S
8
6 km 1
1
132˚E
4
20 January 2006 1800UTC
dBZ
6
0
53
46
39
32
25
18
6 km
130˚E
131˚E
132˚E
Cloud Radar
11
4
dBZ
20
28
ATTENUATED
Height (km)
16
21
14
12
7
8
0
-7
4
-14
0
-21
2200
19Jan06
0000
20Jan06
0200
20Jan06
0400
20Jan06
0600
20Jan06
0800
20Jan06
1000
20Jan06
1200
20Jan06
1400
20Jan06
1600
20Jan06
1800
20Jan06
2000
20Jan06
-28
Longer-term
records of
the water
budget
parameters
also are
being
derived.
Figures here
are for
duration of
TWP-ICE.
TWP-ICE
Precipitation
Radar Rain Rate
(~20 % stratiform)
TWP-ICE Cloud Radar
Anvil Frequency
This will also
be done for a
longer-term
climatology.
We will use
cloud &
precipitation
radars
permanently
located at
Darwin.
Ac
Water budget parameters empirical
Cloud radar  As
Precip radar  Rs
Doppler & soundings  As, Csu, CT
Field projects, CloudSat,…
As


E  a C  C 
A  b C  C 
Rs   s Csu  CT
sd
s
su
su
T
T
where
 s  a  b  1  error