! An Update on CAM-CLUBB Coupled Simulations

Transcription

1 ! An Update on CAM- Coupled Simulations! Peter Bogenschutz, Andrew Gettelman, Vincent Larson, Cheryl Craig, Hugh Morrison, Jack Chen, Katherine Thayer- Calder, Sean Santos, David Schannen, and Rachel Storer 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 CESM Workshop, AMWG, June 24, 2015

2 = 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 P ( l,q t,w) 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

3 P ( l,q t,w)

4 Model Configurations Physics Deep Convection Shallow Convection PBL Macrophysics Microphysics CAM5 Zhang and McFarlane (1995) Park and Bretherton (2009) Bretherton and Park (2009) Park Morrison and Gettelman (2008)! for stratiform cloud only

5 Model Configurations Physics CAM5 CAM- Deep Convection Shallow Convection PBL Macrophysics Microphysics Zhang and McFarlane (1995) Park and Bretherton (2009) Bretherton and Park (2009) Park Morrison and Gettelman (2008)! for stratiform cloud only Zhang and McFarlane (1995) Gettelman and Morrison (2014)! for stratiform and shallow convective cloud

6 Model Configurations Physics CAM5 CAM- CAM--Deep! (see Thayer-Calder poster) Deep Convection Zhang and McFarlane (1995) Zhang and McFarlane (1995) Shallow Convection Park and Bretherton (2009) PBL Bretherton and Park (2009) Macrophysics Park Microphysics Morrison and Gettelman (2008)! for stratiform cloud only Gettelman and Morrison (2014)! for stratiform and shallow convective cloud Gettelman and Morrison (2014)! for all cloud

7 Model Configurations Physics CAM5 CAM- CAM--Deep! (see Thayer-Calder poster) Deep Convection Zhang and McFarlane (1995) Zhang and McFarlane (1995) Shallow Convection Park and Bretherton (2009) PBL Bretherton and Park (2009) Macrophysics Park Microphysics Morrison and Gettelman (2008)! for stratiform cloud only Gettelman and Morrison (2014)! for stratiform and shallow convective cloud Gettelman and Morrison (2014)! for all cloud

8 Model Configurations Physics CAM5 CAM- CAM--Deep! (see Thayer-Calder poster) Deep Convection Zhang and McFarlane (1995) Zhang and McFarlane (1995) Shallow Convection Park and Bretherton (2009) PBL Bretherton and Park (2009) Macrophysics Park Microphysics Morrison and Gettelman (2008)! for stratiform cloud only Gettelman and Morrison (2014)! for stratiform and shallow convective cloud Gettelman and Morrison (2014)! for all cloud

9 Model Configurations Physics CAM5 CAM- CAM--Deep! (see Thayer-Calder poster) Deep Convection Zhang and McFarlane (1995) Zhang and McFarlane (1995) Shallow Convection Park and Bretherton (2009) PBL Bretherton and Park (2009) Macrophysics Park Microphysics Morrison and Gettelman (2008)! for stratiform cloud only Gettelman and Morrison (2014)! for stratiform and shallow convective cloud Gettelman and Morrison (2014)! for all cloud Coupling between and Microphysics: Prognostic precipitation microphysics (Gettelman and Morrison 2014) Sub-stepping of and microphysics (Gettelman et al. 2014): time step is 5 min, physics time step is typically 30 mins. Every time is called, microphysics is called Allows for the clouds, convection, turbulence to evolve with the microphysics

10 Model Configurations Physics CAM5 CAM- CAM--Deep! (see Thayer-Calder poster) Deep Convection Zhang and McFarlane (1995) Zhang and McFarlane (1995) Shallow Convection Park and Bretherton (2009) PBL Bretherton and Park (2009) Macrophysics Park Microphysics Morrison and Gettelman (2008)! for stratiform cloud only Gettelman and Morrison (2014)! for stratiform and shallow convective cloud Gettelman and Morrison (2014)! for all cloud Coupling between and Microphysics: Prognostic precipitation microphysics (Gettelman and Morrison 2014) Sub-stepping of and microphysics (Gettelman et al. 2014): time step is 5 min, physics time step is typically 30 mins. Every time is called, microphysics is called Allows for the clouds, convection, turbulence to evolve with the microphysics

11 Model Configurations Physics CAM5 CAM- CAM--Deep! (see Thayer-Calder poster) Deep Convection Zhang and McFarlane (1995) Zhang and McFarlane (1995) Shallow Convection Park and Bretherton (2009) PBL Bretherton and Park (2009) Macrophysics Park Microphysics Morrison and Gettelman (2008)! for stratiform cloud only Gettelman and Morrison (2014)! for stratiform and shallow convective cloud Gettelman and Morrison (2014)! for all cloud Coupling between and Microphysics: Prognostic precipitation microphysics (Gettelman and Morrison 2014) Sub-stepping of and microphysics (Gettelman et al. 2014): time step is 5 min, physics time step is typically 30 mins. Every time is called, microphysics is called Allows for the clouds, convection, turbulence to evolve with the microphysics

12 Old CESM- 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- 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

13 Old CESM- 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- 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

14 Old vs. New CESM- Simulations Many CESM- 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 tag) Without any tuning, we serendipitously achieved a reasonable PI radiation balance, reasonable mean state climate, and a decent ENSO

15 Old vs. New CESM- Simulations Many CESM- 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 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

16 ENSO 3.4 Monthly Standard Deviations (C) HADISST Obs CESM-LE Control Plots by CVDP CESM- Old CESM- New

17 Why the Improvement? Improvement appears mostly due to new CAM tag (updated topography file) and new tag (better Sc to Cu transition)

18 Why the Improvement? Improvement appears mostly due to new CAM tag (updated topography file) and new tag (better Sc to Cu transition) Sea Surface Temperature (New - Old) All plots are years of pre-industrial control

19 Why the Improvement? Improvement appears mostly due to new CAM tag (updated topography file) and new tag (better Sc to Cu transition) Sea Surface Temperature (New - Old) Surface Stress (New - Old) All plots are years of pre-industrial control

20 Why the Improvement? Improvement appears mostly due to new CAM tag (updated topography file) and new tag (better Sc to Cu transition) Sea Surface Temperature (New - Old) Surface Stress (New - Old) Shortwave Cloud Forcing (New - Old) All plots are years of pre-industrial control

21 CAM- 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- 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- 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

22 CAM- 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- 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- 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 Temperature Anomaly (K) Observations (MLOST) CESM LE 1 CESM 20th Century Surface Temperature Year

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

24 CAM5.4- Simulations (CAM5.5) SWCF (CAM CAM5.3+-) Introduction of CAM5.4 options has significant impacts on the top of atmosphere radiation budget: RESTOM (10/year simulation): LWCF (CAM CAM5.3+-) CAM5.3+-: W/m2 CAM5.4-: 1.47 W/m2 Significant tuning required to achieve PI radiation balance once again.

25 CAM5.4- Simulations (CAM5.5) Thus far we have tuned CAM5.4- 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- Preliminary CAM5.4- simulations are competitive with CAM5.4

26 CAM5.4- Simulations (CAM5.5) Thus far we have tuned CAM5.4- 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- Preliminary CAM5.4- simulations are competitive with CAM5.4

27 CAM5.4- Simulations (CAM5.5) Thus far we have tuned CAM5.4- 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- Preliminary CAM5.4- simulations are competitive with CAM5.4

28 CAM5.4- Coupled Simulations Early CAM5.4- coupled simulations show much improved double ITCZ and southern ocean wind stress biases compared to CAM5.4. DJF CESM-CAM5.4- CESM-CAM5.4

29 CAM5.4- Coupled Simulations Differences in SWCF CESM- Old - CERES-EBAF CESM-CAM5.3 - CERES-EBAF

30 CAM5.4- Coupled Simulations Differences in SWCF CESM- Old - CERES-EBAF CESM-CAM5.3 - CERES-EBAF CESM-CAM CERES-EBAF

31 CAM5.4- Coupled Simulations Differences in SWCF CESM- Old - CERES-EBAF CESM-CAM5.3 - CERES-EBAF CESM-CAM CERES-EBAF CESM-CAM5.4 - CERES-EBAF

32 CAM5.4- Coupled Simulations Surface Stresses, AMOC, and Cooling CESM-CAM5.4 - ERS CESM-CAM ERS

33 CAM5.4- Coupled Simulations Surface Stresses, AMOC, and Cooling CESM-CAM5.4 - ERS! Surface Temp. RESTOM = 0.08 W/m2 CESM-CAM ERS Max Atlantic Overturning CESM-CAM5.4-

34 Future Work Two priorities moving forward: Focus on getting stable control run of CAM5.4- (CAM5.5) Working on improvements of Kelvin Wave simulation High resolution CAM- simulations: Larson, Gettelman, et. al. CSL proposal awarded 20 M core hours. Focus on variable mesh and 0.25 degree AMIP runs Both CAM- and CAM--DEEP will be tested