An Update on CAM-CLUBB Coupled Simulations...An Update on CAM-CLUBB Coupled Simulations!! Peter Bogenschutz, Andrew Gettelman, Vincent Larson, Cheryl Craig, Hugh Morrison, Jack Chen,

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An Update on CAM-CLUBB Coupled Simulations

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Peter Bogenschutz, Andrew Gettelman, Vincent Larson, Cheryl Craig, Hugh Morrison, Jack Chen, Katherine Thayer-

Calder, Sean Santos, David Schannen, and Rachel Storer

CESM Workshop, AMWG, June 24, 2015

Thanks to: Cecile Hannay, John Truesdale, Brian Medeiros, Xue Zheng, Terry Kubar, Peter Caldwell Robert Pincus, Dan Grosvenor, Dave Williamson, Jen

Kay, Sungsu Park, Matt Wyant, Huan Guo, Chris Golaz, Gokhan Danabasoglu, and many others…

CLUBB

• CLUBB = Cloud Layers Unified By Binormals

• First developed by Golaz et al. (2002), maintained by University of Wisconsin Milwaukee (Vincent Larson’s group)

• “Incomplete” third-order turbulence closure (predicting 9 second and third order moments), centered around a trivariate assumed double gaussian PDF

• CLUBB uses assumed double Gaussian PDF to close SGS cloud and turbulence

• Should provide a unified treatment of PBL, shallow convection, and cloud macrophysics that drives a single microphysics scheme

• Implemented in CAM5 and AM3 as part of Climate Process Team

P (�l, qt, w)

P (�l, qt, w)

Physics

Deep Convection

Shallow ConvectionPBLMacrophysicsMicrophysics

CAM5

Zhang and McFarlane (1995)

Park and Bretherton (2009)Bretherton and Park (2009)

Park Morrison and Gettelman

(2008)!for stratiform cloud only

Model Configurations

Physics

Deep Convection


CAM5





CAM-CLUBB

Zhang and McFarlane (1995)CLUBBCLUBBCLUBB

Gettelman and Morrison (2014)!

for stratiform and shallow convective cloud


Physics

Deep Convection


CAM5





CAM-CLUBB




CAM-CLUBB-Deep!(see Thayer-Calder poster)

CLUBB

CLUBBCLUBBCLUBB


for all cloud


Physics

Deep Convection


CAM5





CAM-CLUBB





CLUBB

CLUBBCLUBBCLUBB


for all cloud


Physics

Deep Convection


CAM5





CAM-CLUBB





CLUBB

CLUBBCLUBBCLUBB


for all cloud


Physics

Deep Convection


CAM5





CAM-CLUBB





CLUBB

CLUBBCLUBBCLUBB


for all cloud


• Coupling between CLUBB and Microphysics:

• Prognostic precipitation microphysics (Gettelman and Morrison 2014)

• Sub-stepping of CLUBB and microphysics (Gettelman et al. 2014):

• CLUBB time step is 5 min, physics time step is typically 30 mins.

• Every time CLUBB is called, microphysics is called

• Allows for the clouds, convection, turbulence to evolve with the microphysics

Physics

Deep Convection


CAM5





CAM-CLUBB





CLUBB

CLUBBCLUBBCLUBB


for all cloud








Physics

Deep Convection


CAM5





CAM-CLUBB





CLUBB

CLUBBCLUBBCLUBB


for all cloud








“Old” CESM-CLUBB Simulations

• Prescribed SST simulations yielded competitive simulations with CAM5

• February 2015 CAM5.5 panel review identified the poor simulation of ENSO as a major concern

• CESM-CLUBB simulation of ENSO was too weak and with no preferred mode of variability

• Tropical Pacific surface stress was too easterly, causing too much upwelling and relatively cold tropical SSTs

“Old” CESM-CLUBB Simulations

• Prescribed SST simulations yielded competitive simulations with CAM5

• February 2015 CAM5.5 panel review identified the poor simulation of ENSO as a major concern

• CESM-CLUBB simulation of ENSO was too weak and with no preferred mode of variability

• Tropical Pacific surface stress was too easterly, causing too much upwelling and relatively cold tropical SSTs

Plots by CVDP

Old vs. New CESM-CLUBB Simulations

• Many CESM-CLUBB sensitivity simulations were performed

• One test was to “upgrade” all of our code tags to the most current tags at that time (i.e. newest CESM tag, newest CAM tag, newest CLUBB tag)

• Without any tuning, we serendipitously achieved a reasonable PI radiation balance, reasonable mean state climate, and a decent ENSO

Old vs. New CESM-CLUBB Simulations

• Many CESM-CLUBB sensitivity simulations were performed

• One test was to “upgrade” all of our code tags to the most current tags at that time (i.e. newest CESM tag, newest CAM tag, newest CLUBB tag)

• Without any tuning, we serendipitously achieved a reasonable PI radiation balance, reasonable mean state climate, and a decent ENSO

Old New

Plots by CVDP

ENSO 3.4 Monthly Standard Deviations (C)

HADISST Obs CESM-LE Control

CESM-CLUBB Old CESM-CLUBB New

Plots by CVDP

Why the Improvement?

• Improvement appears mostly due to new CAM tag (updated topography file) and new CLUBB tag (better Sc to Cu transition)



Sea Surface Temperature (New - Old)

All plots are years 80-100 of pre-industrial control



Surface Stress (New - Old)





Shortwave Cloud Forcing (New - Old)

Surface Stress (New - Old)



CAM-CLUBB Coupled Simulations• The “New” coupled simulation presented here is overall better than the “Old”

coupled simulation submitted for panel review this past winter

• All the “good” aspects of CAM-CLUBB are retained (full diagnostics available to the community)

• Taylor score is nearly identical between “Old” and “New” simulation. However, the “New” simulation was not tuned at all, thus it would have been very easy to achieve even better skill score metrics had we tuned the “New” CESM-CLUBB

• Although climate sensitivity and aerosol effect experiments were not performed with this new simulation, we have no reason suspect these would change, nor would a successful 20th century simulation…

CAM-CLUBB Coupled Simulations• The “New” coupled simulation presented here is overall better than the “Old”

coupled simulation submitted for panel review this past winter

• All the “good” aspects of CAM-CLUBB are retained (full diagnostics available to the community)

• Taylor score is nearly identical between “Old” and “New” simulation. However, the “New” simulation was not tuned at all, thus it would have been very easy to achieve even better skill score metrics had we tuned the “New” CESM-CLUBB

• Although climate sensitivity and aerosol effect experiments were not performed with this new simulation, we have no reason suspect these would change, nor would a successful 20th century simulation…

1850 1900 1950 2000−0.6

−0.4

−0.2

0

0.2

0.4

0.6

0.820th Century Surface Temperature

Year

Tem

pera

ture

Ano

mal

y (K

)

Observations (MLOST)CESM−LE−1CESM−CLUBB

CAM5.4-CLUBB Simulations (CAM5.5)

• “New” coupled simulation performed thus far are what we call CAM5.3+

• Performed with a recent CAM development tag that has some CAM5.4 options turned on by default (i.e. new topography file, energy changes, etc.), plus MG2 (which is the default microphysics for CLUBB)

• We are now pursuing coupled simulations with all CAM5.4 options turned ON

• This includes new ice nucleation, MAM4, 32-levels, and mode width changes

• All CAM5.4-CLUBB developments are currently on the trunk and ready to turn on (only thing to be decided are tuning parameters)


• Introduction of CAM5.4 options has significant impacts on the top of atmosphere radiation budget:

• RESTOM (10/year simulation):

• CAM5.3+-CLUBB: -0.03 W/m2

• CAM5.4-CLUBB: 1.47 W/m2

• Significant tuning required to achieve PI radiation balance once again.

SWCF (CAM5.4-CLUBB - CAM5.3+-CLUBB)

LWCF (CAM5.4-CLUBB - CAM5.3+-CLUBB)


• Thus far we have tuned CAM5.4-CLUBB to achieve RESTOM ~ 0.0 W/m2 in three configurations that were run for 50 years.

• All these simulations have cooled too much, with the bulk of the cooling occurring in the northern hemisphere.

• We are currently investigating why. Some possibilities are:

• Increase of aerosols in the North Pacific with CAM5.4

• Sensitivity to initial conditions?

• Weakening AMOC

• Good ENSO simulation appears to hold in CAM5.4-CLUBB

• Preliminary CAM5.4-CLUBB simulations are competitive with CAM5.4







• Weakening AMOC









• Weakening AMOC



CAM5.4-CLUBB Coupled Simulations• Early CAM5.4-CLUBB coupled simulations show much improved double

ITCZ and southern ocean wind stress biases compared to CAM5.4.

DJF

CESM-CAM5.4-CLUBB CESM-CAM5.4

CAM5.4-CLUBB Coupled Simulations Differences in SWCF

CESM-CLUBB Old - CERES-EBAF CESM-CAM5.3 - CERES-EBAF


CESM-CAM5.4-CLUBB - CERES-EBAF

CESM-CLUBB Old - CERES-EBAF CESM-CAM5.3 - CERES-EBAF


CESM-CAM5.4-CLUBB - CERES-EBAF

CESM-CLUBB Old - CERES-EBAF

CESM-CAM5.4 - CERES-EBAF

CESM-CAM5.3 - CERES-EBAF

CAM5.4-CLUBB Coupled Simulations Surface Stresses, AMOC, and Cooling

CESM-CAM5.4 - ERS

CESM-CAM5.4-CLUBB - ERS

CAM5.4-CLUBB Coupled Simulations Surface Stresses, AMOC, and Cooling

CESM-CAM5.4 - ERS

CESM-CAM5.4-CLUBB - ERS

Max Atlantic Overturning CESM-CAM5.4-CLUBB

!Surface Temp.

RESTOM = 0.08 W/m2

Future Work

• Two priorities moving forward:

• Focus on getting stable control run of CAM5.4-CLUBB (CAM5.5)

• Working on improvements of Kelvin Wave simulation

• High resolution CAM-CLUBB simulations:

• Larson, Gettelman, et. al. CSL proposal awarded 20 M core hours.

• Focus on variable mesh and 0.25 degree AMIP runs

• Both CAM-CLUBB and CAM-CLUBB-DEEP will be tested

Documents

An Update on CAM-CLUBB Coupled Simulations...An Update on CAM-CLUBB Coupled Simulations!! Peter Bogenschutz, Andrew Gettelman, Vincent Larson, Cheryl Craig, Hugh Morrison, Jack Chen,