Assessment of NASA GISS CMIP5 and post-CMIP5 Simulated Clouds and Radiation fluxes Using Satellite Observations 1/15/2019 Ryan Stanfield(1), Xiquan Dong(1), Baike Xi(1), Aaron Kennedy(1), Anthony D. Del Genio(2), Patrick Minnis(3), David Doelling(3), Norman Loeb(3), Jonathan Jiang(4) (1) University of North Dakota (2) NASA GISS (3) NASA Langley Research Center (4) JPL – Jet Propulsion Laboratory This talk is based on the papers of Stanfiled et al. (2014a, b, J. Climate)  

Our Interest and Focus Zonal averages 1/15/2019 Most GCMs in CMIP5 simulated less Marine Stratocumulus clouds over the SMLs Provided by: Erica Dolinar

Data Sets GCM Simulations: Two versions of the NASA GISS-E2 GCM 40 vertical layers 2°x2.5° (latitude x longitude) (C5) CMIP5 GISS-E2 Model AMIP r5i1p3 run (P5) Post-CMIP5 GISS-E2 Model Diagnostic Interim Atmospheric Run, 2 Major Modifications Cumulus parameterization - (Del Genio et al., 2012) Increased entrainment and rain evaporation. Changes in the convective downdraft. Boundary layer turbulence parameterization (Yao and Cheng, 2012) Computation of nonlocal transports. Turbulent length scale. PBL height. 1/15/2019

Satellite Data CERES-MODIS (CM) CloudSat/CALIPSO (CC) AIRS (AIRS) SYN1 dataset 1°x 1°  2°x 2.5° grid box 2000/03 – 2005/12 CloudSat/CALIPSO (CC) 2B-CWC-RO dataset : Calypso IWP, LWP, IWC, and LWC 2°x 2.5° grid generated from observations 2006/07 – 2010/06 ______________________________________________________________________________ AIRS (AIRS) AIRX3STM dataset 2002/09 – 2012/12 AMSR-E (AMSRe) 2002/07 – 2011/07 0.25°x 0.25°  2°x 2.5° grid box _________________________________________________________________________ CERES-EBAF (CE) Used for radiative comparisons 1/15/2019

Cloud [%] Fraction CloudSat CALIPSO (CC) Post-CMIP5 GISS-E2 (P5) CMIP5 CERES-MODIS (CM) 1/15/2019 Post-CMIP5 GISS-E2 (P5) CMIP5 GISS-E2 (C5) P5 - CM C5 - CM P5 - CC C5 - CC

Total Cloud Fraction High CF Mid CF Low CF > 440 mb Variable Model Observation Bias RMSE Correlation Quicklook CF (Total) [%] P5 CM −7.6 9.01 0.90 I,I,I C5 −19.1 20.45 0.74 CC −13.7 14.37 −25.2 26.08 0.75 (High) 4.2 5.82 W,W,I −1.7 4.31 0.64 −1.9 4.84 0.68 −7.8 9.05 0.67 (Mid) 9.4 10.39 0.82 3.1 6.8 0.71 −5.1 6.78 0.92 −11.4 13.48 0.84 (Low) 17.9 24.42 0.53 I,W,I −20.2 21.99 0.24 7.5 12.14 0.87 −30.6 32.04 0.70 Total Cloud Fraction 1/15/2019 High CF > 440 mb Mid CF 440 < P < 680 Low CF < 680 mb Changes to the PBL scheme implemented in the GISS P5 GCM have increased low level CF by nearly 20% (compared to C5), bringing total column CF closer to both CM and CC.

Cloud [g m-2] Water Path CloudSat CALIPSO (CC) Post-CMIP5 GISS-E2 (P5) CERES-MODIS (CM) 1/15/2019 Post-CMIP5 GISS-E2 (P5) CMIP5 GISS-E2 (C5) P5 - CM C5 - CM P5 - CC C5 - CC

Total Cloud Water Path Liquid Water Path Ice Water Path Cloud Fraction Variable Model Observation Bias RMSE Correlation Quicklook CWP [g / m2] P5 CM −19.5 68.62 0.43 W,I,I C5 2.2 68.99 0.36 CS 6.3 45.96 0.51 I,I,I 28.0 60.84 0.34 LWP −3.9 26.4 0.53 21.1 49.61 0.12 IWP 10.2 50.38 0.08 W,W,W 6.8 49.87 0.04 Total Cloud Fraction 1/15/2019 Cloud Water Path Liquid Water Path Ice Water Path Over the tropics, the decrease in CWP from the C5 to the P5 version of the model is consistent with the decrease observed in total column CF. Whereas comparing CWP and total column CF over the SMLs shows the opposite relationship, most likely an artifact due to a shift from stratiform cloud to shallow convection, whose condensate is not accounted for in the CWP diagnostic

AMSRe Post-CMIP5 GISS-E2 (P5) CMIP5 GISS-E2 (C5) P5 - AIRS C5 - AIRS Precip. Water Vapor (PWV) [g m-2] AMSRe AIRS 1/15/2019 Post-CMIP5 GISS-E2 (P5) CMIP5 GISS-E2 (C5) P5 - AIRS C5 - AIRS P5 - AMSRe C5 - AMSRe

Variable Model Observation Bias RMSE Correlation Quicklook PWV (ALL) [g / m2] P5 AIRS 1.3 1.66 0.98 W,W,- C5 0.0 0.97 (Ocean) 1.67 0.1 0.87 AMSR-E −0.6 1.07 0.99 I,I,- −1.8 1.92 PWV 1/15/2019 PWV (Water Only) SST Over the ocean, the P5 results agree better with AMSR-E retrievals globally, particularly over the SMLs.

Post-CMIP5 GISS-E2 (P5) P5 - AIRS CMIP5 GISS-E2 (C5) C5 - AIRS RH Profiles AIRS 1/15/2019 Post-CMIP5 GISS-E2 (P5) P5 - AIRS CMIP5 GISS-E2 (C5) C5 - AIRS Over the SMLs, the P5 and C5 low-level RHs are ~10% higher and lower than the AIRS retrievals, respectively. This is consistent with our CF comparison and provides strong support for the increase in the number of low-level clouds simulated by P5.

Variable Model Observation Bias RMSE Correlation Quicklook CF (Total) [%] P5 CM −7.6 9.01 0.90 I,I,I C5 −19.1 20.45 0.74 CC −13.7 14.37 −25.2 26.08 0.75 (High) 4.2 5.82 W,W,I −1.7 4.31 0.64 −1.9 4.84 0.68 −7.8 9.05 0.67 (Mid) 9.4 10.39 0.82 3.1 6.8 0.71 −5.1 6.78 0.92 −11.4 13.48 0.84 (Low) 17.9 24.42 0.53 I,W,I −20.2 21.99 0.24 7.5 12.14 0.87 −30.6 32.04 0.70 CWP [g / m2] −19.5 68.62 0.43 W,I,I 2.2 68.99 0.36 CS 6.3 45.96 0.51 28.0 60.84 0.34 LWP −3.9 26.4 21.1 49.61 0.12 IWP 10.2 50.38 0.08 W,W,W 49.87 0.04 PWV (ALL) AIRS 1.3 1.66 0.98 W,W,- 0.0 0.97 (Ocean) 1.67 0.1 AMSR-E −0.6 1.07 0.99 I,I,- −1.8 1.92 1/15/2019 Over the SMLs, we see excellent agreement between the P5 simulation, CS/CC, and AMSR-E observations.

OLR 1/15/2019 SW ABS Albedo P5/C5/CE Clear-Sky All-Sky Changes to the P5 low-level CF have had a minimal impact on OLR but a large impact on all-sky albedo and SW absorption, as can be expected.

Total Column CF P5/C5/CE CWP 1/15/2019 LW CRE SW CRE Net CRE Biases between CE observations and P5 version of the model have decreased in LW/SW CRE. Differences between modeled and observed LW and Net CRE are predominantly due to differences in clear-sky OLR.

CF comparisons over the SMLs P5/C5 compared to CM P5/C5 compared to CC 1/15/2019 Great improvement in the modeled total column CF is observed in the new P5 simulation, primarily due to the modifications made to the boundary layer parameterization.

Relationship between SW CRE and CF over the SMLs P5/C5/CE 1/15/2019 The correlation and slope between SW CRE and CF in the P5 simulations more closely resembles CE observations.

Conclusions Overall, the changes implemented in the latest GISS P5 GCM, especially the changes in boundary layer depth, have shown a significant improvement in model-simulated clouds and cloud properties. Low-level P5 cloud fractions have increased by ~20%, bringing the modeled total column cloud fraction in the SMLs closer to both CM and CC observations. P5 simulated PWV matches closely with AMSR-E observations. Low-level RH has increased over the SMLs in the P5 simulation, corresponding well with our CF comparison. Biases in both LW and SW CRE have decreased. Differences between P5 and CE LW and Net CRE are predominantly due to differences in clear-sky OLR. The correlation and slope between CF and SW CRE in the P5 simulations more closely resembles CE observations. 1/15/2019

Thanks for your attention and Support from Xiquan Dong’s research group

< Reference Slides > Ryan Stanfield

1/15/2019

Stats-Global 1/15/2019 Variable Model Observation Bias RMSE Correlation Quicklook CF (Total) [%] P5 CM −0.3 14.98 0.64 I,I,I C5 −0.9 16.49 0.39 CC −13.0 15.69 0.75 −13.6 17.37 0.59 (High) 5.1 11.74 0.63 W,W,I −2.9 10.02 0.58 9.40 0.68 I,I,W −8.3 10.18 (Mid) 8.5 13.74 W,W,- 3.0 10.04 −4.2 6.89 0.90 −9.7 12.51 0.80 (Low) 16.2 30.20 0.57 −7.0 16.33 0.44 7.4 22.36 0.61 I,W,I −15.8 21.51 0.49 CWP [g / m2] 42.3 99.23 0.46 68.9 111.95 0.43 CS 26.0 78.77 0.67 52.6 90.46 0.65 LWP 29.62 24.6 57.5 0.38 IWP 35.3 84.68 0.54 W,W,W 27.7 73.82 PWV (ALL) AIRS 1.4 2.45 0.99 −0.4 1.76 (Ocean) 2.3 2.82 0.4 1.66 AMSR-E 0.3 2.66 I,W,- 1/15/2019

Stats-SML 1/15/2019 Variable Model Observation Bias RMSE Correlation Quicklook CF (Total) [%] P5 CM −7.6 9.01 0.90 I,I,I C5 −19.1 20.45 0.74 CC −13.7 14.37 −25.2 26.08 0.75 (High) 4.2 5.82 W,W,I −1.7 4.31 0.64 −1.9 4.84 0.68 −7.8 9.05 0.67 (Mid) 9.4 10.39 0.82 3.1 6.8 0.71 −5.1 6.78 0.92 −11.4 13.48 0.84 (Low) 17.9 24.42 0.53 I,W,I −20.2 21.99 0.24 7.5 12.14 0.87 −30.6 32.04 0.70 CWP [g / m2] −19.5 68.62 0.43 W,I,I 2.2 68.99 0.36 CS 6.3 45.96 0.51 28.0 60.84 0.34 LWP −3.9 26.4 21.1 49.61 0.12 IWP 10.2 50.38 0.08 W,W,W 49.87 0.04 PWV (ALL) AIRS 1.3 1.66 0.98 W,W,- 0.0 0.97 (Ocean) 1.67 0.1 AMSR-E −0.6 1.07 0.99 I,I,- −1.8 1.92 1/15/2019