CCSM4 (CAM4) Tuning Parameter Perturbation Study T85T85.F1850

 

notes: all simulations run at Oak Ridge on Jaguar control simulation

(all default values) = isolated perturbaton simulations (value' per param)

 


Parameter

Default Value

Changed

Value

Code Location

Parameter Function/Description

rhminl

.90

.45

namelist: cldfrc_rhminl (cloud_fraction.F90)

minimum rh for low stable clouds

rhminh

.77

.385

namelist: cldfrc_rhminh (cloud_fraction.F90)

minimum rh for high stable clouds

sh1

.04

.4

cloud_fraction.F90

parameter for shallow convection cloud fraction, code: shallowcu = max(0.0_r8,min(sh1*log(1.0_r8+sh2*cmfmc2(i,k+1)),0.30_r8))

sh2

500

5000.

cloud_fraction.F90

parameter for shallow convection cloud fraction, " "

dp1

.1

1.0

cloud_fraction.F90

parameter for deep convection cloud fraction, code: deepcu = max(0.0_r8,min(dp1*log(1.0_r8+dp2*(cmfmc(i,k+1)-cmfmc2(i,k+1))),0.60_r8))

dp2

500.

5000.

cloud_fraction.F90

parameter for deep convection cloud fraction, " "

premit

250.

750.

cloud_fraction.F90

top pressure bound for mid level cloud

r3lcrit

10.0e-6

1.e-6

cldwat.F90

critical radius at which autoconverion becomes efficient

icritc

45.0e-6

4.5 e-6

cldwat.F90

threshold for autoconversion cold ice, code: icrit = icritc*wt + icritw*(1-wt)

icritw

2.e-4

.2 e-4

cldwat.F90

threshold for autoconversion warm ice, " "

conke

5. e-6

.5 e-6

cldwat.F90

tunable constant for evaporation of precip

capnw

400.

800.

cldwat.F90

warm continental cloud particles density /cm3

capnc

150.

75.

cldwat.F90

cold continental and oceanic cloud particles density /cm3

capnsi

75.

30.

cldwat.F90

sea ice cloud particles density /cm3

cmftau

1800.

3600.

hk_conv.F90

characteristic adjustment time scale for moist convection (time over which convection is assumed to act)

c0

5. e-5

5. e-6

hk_conv.F90

rain water autoconversion coefficient for moist convection

tau

3600.

7200.

zm_conv.F90

convection time scale

c0

3.5 e-3

3.5 e-4

zm_conv.F90

used for condensed liquid/rain production rate, tunable param

ke

1.e -6

1.e -5

zm_conv.F90

tunable evaporation efficieny

rliqocean

14.

7.

pkg_cldoptics.F90

liquid drop size over ocean (micron)

rliqland

8.

4.

pkg_cldoptics.F90

liquid drop size over land (micron)

rliqice

14.

7.

pkg_cldoptics.F90

liquid drop size over ice (micron)