Understanding Atmospheric Heating in the GPM Era

Robert HouzeUniversity of Washington

6th GPM International Planning Workshop, 6-8 November 2006, Annapolis, Maryland, USA

Heating algorithms are expected to be an important product of GPM

Relationship of Cloud Water Relationship of Cloud Water Budgets to Heating Profile Budgets to Heating Profile

CalculationsCalculations

Austin and Houze 1973Houze et al. 1980Houze 1982, 1989

Takayabu 2002Shige et al. 2006

Relationship of Cloud Water Relationship of Cloud Water Budgets to Heating Profile Budgets to Heating Profile

CalculationsCalculations

Austin and Houze 1973Houze et al. 1980Houze 1982, 1989

Takayabu 2002Shige et al. 2006

Latent heating only

Total heating

Houze 1982

PREMISEPREMISE

Can also relate eddy & radiative heating profiles to water budget to obtain

Total Heating = Latent + Eddy + Radiative

Houze 1982

PREMISEPREMISE

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 troposphereTropical MCSs inject lots of hydrometeors into upper troposphere

Idealized life cycle of tropical MCS as proposed by Houze 1982

Conv. LH Strat. LH

Rad.Conv. Eddy Strat. Eddy

Contributions to Total Heating by Convective Cloud System Contributions to Total Heating by Convective Cloud System

Details from Houze 1982

TOTAL HEATING

These combine to give “top-heavy” heating profile These combine to give “top-heavy” heating profile

Houze 1982 idealized case

“Top Heavy” profile.

Includes latent, eddy, and radiative heating.

Think of the following schematic as a composite of the water budget of an MCS over its whole life cycle

Think of the following schematic as a composite of the water budget of an MCS over its whole life cycle

After Houze et al. (1980)

AcAs

As

Csu+CT =Rs + Esd + As

Rs=εs Csu +CT( )

Esd =a Csu +CT( )

As =b Csu +CT( )

where

εs + a+b=1

Stratiform water budget equation

As

Ac

Rain not simply related to condensation

AsAs

Ac

Rs=εs Csu +CT( )

Esd =a Csu +CT( )

As =b Csu +CT( )

where

εs + a+b=1±error

Water budget parameters: As , Rs , Csu, CT

Need to be determined empirically Field projects, CloudSat,…

AsAs

Ac

Ccu=Rc + Ecd + Ac +CT

Convective region water budget equation

AsAs

Ac

R = Rcii∑

Ccu = Ccuii∑

Ecd = Ecdii∑

CT = CTii∑

Ac = Acii∑

Rci=ε iCci

Esdi =α iCci

Aci =βiCci

CTi =ηiCci

ε i +α i + βi +ηi =1

Sum over all cloud height categories i

For each height category i

with the constraint

(each height cat.)

AsAs

Ac

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

XAC

ZAC

Using empirically derived values of the water

budget parameters b and εs, the stratiform

regions’ anvil mass is proportional to the stratiform rain

As =(bRs)/εs

200 hPa streamfunction response to CRF assumed proportional to TRMM rain by Schumacher et al. (2004)

400 hPaK/day

SummarySummary

•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 .

•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 ThoughtFinal Thought

•Too ambitious?

•Think 15 years from now!

•Too ambitious?

•Think 15 years from now!

Thank you!

Extra Slides:

13˚S

11˚S

12˚S

130˚E 132˚E131˚E

60534639322518114

dBZ

20 January 2006 0000UTC

6 km

13˚S

11˚S

12˚S

130˚E 132˚E131˚E

60534639322518114

dBZ

20 January 2006 0900UTC

6 km

13˚S

11˚S

12˚S

130˚E 132˚E131˚E

60

53

46

39

32

25

18

11

4

dBZ20 January 2006 1800UTC

6 km

Example from TWP-ICE

dBZ20

220019Jan06

000020Jan06

020020Jan06

040020Jan06

060020Jan06

080020Jan06

100020Jan06

120020Jan06

140020Jan06

160020Jan06

180020Jan06

200020Jan06

28

21

14

7

0

-7

-14

-21

-28

ATTENUATED

Hei

gh

t (k

m)

4

8

12

16

0

Cloud Radar

Precipitation Radar

TWP-ICE Precipitation

Radar Rain Rate(~20 % stratiform)

TWP-ICE Cloud Radar Anvil Frequency

Longer-term records of the water budget parameters also are being derived.

Figures here are for duration of TWP-ICE.

This will also be done for a longer-term climatology.

We will use cloud & precipitation radars permanently located at Darwin.

AsAs

Ac

Rs=εs Csu +CT( )

Esd =a Csu +CT( )

As =b Csu +CT( )

where

εs + a+b=1±error

Cloud radar As

Precip radar Rs

Doppler & soundings As, Csu, CT

Water budget parameters empirical

Field projects, CloudSat,…