Low-Latitude Cloud Feedbacks CPT Chris Bretherton University of Washington, Seattle, USA Goal: Better simulation and understanding of low- latitude [boundary.

Slides:

Advertisements

Similar presentations

Met Office Hadley Centre, FitzRoy Road, Exeter, Devon, EX1 3PB United Kingdom Tel: +44 (0) Fax: +44 (0)

Advertisements

© Crown copyright Met Office Towards understanding the mechanisms responsible for different cloud-climate responses in GCMs. Mark Webb, Adrian Lock (Met.

Water Vapor and Lapse Rate Feedbacks Neil Gordon ESP Seminar April 14, 2006.

Evaluating parameterized variables in the Community Atmospheric Model along the GCSS Pacific cross-section during YOTC Cécile Hannay, Dave Williamson,

Clouds and Climate A. Pier Siebesma KNMI What are clouds? How do they form? Cloud climatology Clouds and Radiation Clouds in Climate models Cloud Climate.

The Problem of Parameterization in Numerical Models METEO 6030 Xuanli Li University of Utah Department of Meteorology Spring 2005.

Low-Latitude Cloud Feedbacks Climate Process Team – Findings and Experiences Chris Bretherton University of Washington, Seattle, USA Goal: Better simulation.

Low-Latitude Cloud Feedbacks CPT Chris Bretherton University of Washington US CLIVAR activity sponsored by NSF and NOAA at ~$1M/yr, along with 2 ocean.

Sc-Cu transition CPT Goal: Improve the representation of the cloudy boundary layer in global weather/climate models with a focus on the subtropical stratocumulus.

Double ITCZ Phenomena in GCM’s Marcus D. Williams.

What have we learned from CGILS? CFMIP/GCSS/EUCLIPSE Meeting, Exeter, 6 th -10 th June 2011 Minghua Zhang, Chris Bretherton, Peter Blossey Phil Austin,

Low clouds in the atmosphere: Never a dull moment Stephan de Roode (GRS) stratocumulus cumulus.

Clouds and Climate: Cloud Response to Climate Change SOEEI3410 Ken Carslaw Lecture 5 of a series of 5 on clouds and climate Properties and distribution.

What controls the climatological PBL depth? Brian Medeiros Alex Hall Bjorn Stevens UCLA Department of Atmospheric & Oceanic Sciences 16th Symposium on.

The Radiative Budget of an Atmospheric Column in Tropical Western Pacific Zheng Liu Department of Atmospheric Science University of Washington.

Clouds and Climate: Cloud Response to Climate Change ENVI3410 : Lecture 11 Ken Carslaw Lecture 5 of a series of 5 on clouds and climate Properties and.

Boundary layer parameterization and climate Chris Bretherton University of Washington.

Cpt.UCLA Our work is motivated by two observations ‣ our understanding of cloud feedbacks is zonally symmetric. ‣ all pbl parameterizations strive to well.

Subtropical low cloud feedback in a superparameterized GCM - a mechanism and a CRM column analogue Peter N. Blossey Matthew C. Wyant Christopher S. Bretherton.

Evening Discussion: Toward a better understanding of PBL cloud feedbacks on climate sensitivity Some introductory material Chris Bretherton University.

Relationships between wind speed, humidity and precipitating shallow cumulus convection Louise Nuijens and Bjorn Stevens* UCLA - Department of Atmospheric.

Adjustment to tropospheric warming over ocean and land surfaces Adam Sobel, John Chiang, Deborah Herceg, Liqiang Sun, Michela Biasutti + many discussions.

National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology Pasadena, California 1 GCSS Pacific Cross-section.

The CFMIP-GCSS SCM/LES Case Study: Overview and Preliminary Results Minghua Zhang (Stony Brook University) Julio Bacmeister, Sandrine Bony, Chris Bretherton,

VOCALS Update Chris Bretherton, Univ. of Washington.

Observational study of the transition from unbroken marine boundary layer stratocumulus to the shallow cumulus regime Irina Sandu and Bjorn Stevens Max-Planck-Institut.

Why are we here, at the UCLA Conf. Center in June 2005? What is the best way of representing the physics of the atmospheric PBL in weather and climate.

© Crown copyright Met Office Using stability composites to analyse cloud feedbacks in the CMIP3/CFMIP-1 slab models. Mark Webb (Met Office) CFMIP-GCSS.

The Response of Marine Boundary Layer Clouds to Climate Change in a Hierarchy of Models Chris Jones Department of Applied Math Advisor: Chris Bretherton.

A Mechanism for Low Cloud Response in SP-CAM Matthew C. Wyant Christopher S. Bretherton Peter Blossey Department of Atmospheric Sciences University of.

Towards stability metrics for cloud cover variation under climate change Rob Wood, Chris Bretherton, Matt Wyant, Peter Blossey University of Washington.

Large-Eddy Simulation of a stratocumulus to cumulus transition as observed during the First Lagrangian of ASTEX Stephan de Roode and Johan van der Dussen.

© Crown copyright Met Office CFMIP-2 techniques for understanding cloud feedbacks in climate models. Mark Webb (Met Office Hadley Centre) CFMIP/GCSS BLWG.

The VOCALS Assessment (VOCA) Matt Wyant, Chris Bretherton, Rob Wood Department of Atmospheric Sciences University of Washington Scott Spak, U. Iowa (Emissions)

Vertical Structure of the Tropical Troposphere (including the TTL) Ian Folkins Department of Physics and Atmospheric Science Dalhousie University.

Observational and model evidence for positive low-level cloud feedback Robert J. Burgman and Amy C. Clement Rosenstiel School of Marine and Atmospheric.

Stephan de Roode (KNMI) Entrainment in stratocumulus clouds.

Update on model developments: Meteo-France NWP model / clouds and turbulence CLOUDNET workshop / Paris 27-28/05/2002 Jean-Marcel Piriou Centre National.

Clouds in the Southern midlatitude oceans Catherine Naud and Yonghua Chen (Columbia Univ) Anthony Del Genio (NASA-GISS)

Arctic Cloud Biases in CCSM3 Steve Vavrus Center for Climatic Research University of Wisconsin.

CCSM3.5+ Coupled Experiments Rich Neale Phil Rasch, Cecile Hannay, Jon Wolfe, Steve Yeager.

The ASTEX Lagrangian model intercomparison case Stephan de Roode and Johan van der Dussen TU Delft, Netherlands.

Forecast simulations of Southeast Pacific Stratocumulus with CAM3 and CAM3-UW. Cécile Hannay (1), Jeffrey Kiehl (1), Dave Williamson (1), Jerry Olson (1),

Climate forcing, adjustment and feedback Christopher S. Bretherton Atmospheric Sciences and Applied Mathematics University of Washington with help from.

Simple tropical models and their relationship to GCMs Adam Sobel, Columbia Chris Bretherton, U. Washington.

Goal: Isolate SP-CAM low cloud response in a simpler setting and examine its resolution sensitivity. Key assumptions: (like Zhang & Bretherton 2008, Caldwell.

Large Eddy Simulation of Low Cloud Feedback to a 2-K SST Increase Anning Cheng 1, and Kuan-Man Xu 2 1. AS&M, Inc., 2. NASA Langley Research Center, Hampton,

Boundary Layer Clouds.

Sensitivity to the PBL and convective schemes in forecasts with CAM along the Pacific Cross-section Cécile Hannay, Jeff Kiehl, Dave Williamson, Jerry Olson,

Workshop on Tropical Biases, 28 May 2003 CCSM CAM2 Tropical Simulation James J. Hack National Center for Atmospheric Research Boulder, Colorado USA Collaborators:

Robert Wood, Atmospheric Sciences, University of Washington The importance of precipitation in marine boundary layer cloud.

Trends in Tropical Water Vapor ( ): Satellite and GCM Comparison Satellite Observed ---- Model Simulated __ Held and Soden 2006: Robust Responses.

VOCALS Update Chris Bretherton, Univ. of Washington.

National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology Pasadena, California 1 João Teixeira Jet Propulsion.

Yuqing Wang and Chunxi Zhang International Pacific Research Center University of Hawaii at Manoa, Honolulu, Hawaii.

Evaluation of radiative properties of low and high clouds in different regimes using satellite measurements Bing Lin 1, Pat Minnis 1, and Tai-Fang Fan.

Large-scale transient variations of tropical deep convection forced with zonally symmetric SSTs Zhiming Kuang Dept. Earth and Planetary Sciences and School.

CGILS Updated Results GCSS-BLCWG Meeting, September 29-30, 2010 KNMI Minghua Zhang, Chris Bretherton, Peter Blossey Phil Austin, Julio Bacmeister, Sandrine.

CGILS Updated Results GCSS-BLCWG Meeting, September 29-30, 2010 KNMI Minghua Zhang (Stony Brook University) Julio Bacmeister, Sandrine Bony, Chris Bretherton,

Stephan de Roode The art of modeling stratocumulus clouds.

Important data of cloud properties for assessing the response of GCM clouds in climate change simulations Yoko Tsushima JAMSTEC/Frontier Research Center.

Impact of Convective Triggering Mechanisms on CAM2 Model Simulations Shaocheng Xie, Gerald L. Potter, Richard T. Cederwall, and James S. Boyle Atmospheric.

Key ingredients in global hydrological response to external forcing Response to warming => Increased horizontal moisture fluxes => Poleward expansion of.

Forecasts of Southeast Pacific Stratocumulus with the NCAR, GFDL and ECMWF models. Cécile Hannay (1), Dave Williamson (1), Jim Hack (1), Jeff Kiehl (1),

NCAR-GFDL Workshops on Model Development

VOCALS Update Chris Bretherton, Univ. of Washington

Short Term forecasts along the GCSS Pacific Cross-section: Evaluating new Parameterizations in the Community Atmospheric Model Cécile Hannay, Dave Williamson,

Cloud-topped boundary layer response time scales in MLM and LES

VOCALS Update Chris Bretherton, Univ. of Washington

Rob Wood, Chris Bretherton, Matt Wyant, Peter Blossey

Presentation transcript:

Low-Latitude Cloud Feedbacks CPT Chris Bretherton University of Washington, Seattle, USA Goal: Better simulation and understanding of low- latitude [boundary layer] cloud feedbacks in present and perturbed climates within NCAR, GFDL, GMAO AGCMs and in the superparameterized CAM.

CPT history October Sept. 2006, NSF/NOAA funded CPT overviews: Spring 04, 06 US CLlVAR Variations 8 funded PIs (Bretherton, Khairoutdinov, Lappen, Mapes, Pincus, B. Stevens, Xu, M. Zhang) + NCAR (Kiehl), GFDL (Held), some GMAO participation. Liaisons at NCAR (Cecile Hannay), GFDL (Ming Zhao). 7 submitted publications. Collaborations with CAPT, GCSS. Proposal submitted for 2 year continuation, restricted to boundary layer cloud feedbacks. Annual meetings + telecons.

Regime-binned cloud climatology ISCCP simulator results from superparameterization more realistic than GCMs, though not perfect. Wyant et al (Clim Dyn, GRL)

CAM3-SP SST+2 climate sensitivity Based on 3.5 yr ctrl, SST+2 runs Strong negative shortwave cloud feedbacks in tropics, extratropics, esp. from subsidence regimes. Mean BL cloud thickness and fraction both increase CAM3-SP = 0.41 K/(W m -2 ) vs. CAM3 = 0.54 K/(W m -2 ) Global CRM, DARE results similar. Wyant et al (GRL)

Single-column analysis CAM3 GFDL SE Pac Sc (85W 20S), October, every timestep Mapes

SCM intercomparison (a la Betts-Ridgway, Larsen et al) Single column in subtropical subsidence regime Radiative/advective forcings maintain moist-adiabatic, fixed RH profile in free trop. Plausible framework for analyzing –intermodel CTBL structure differences (previous slide) –cloud response to climate warming. Led by Minghua Zhang Warm SSTCold SST (moist adiabat) T(z) RH Fixed

Forcings (maintain steady state w/o CTBL) T w =27 o C T w =29 o C TOGA-COARE Free trop RH=15% T s = T w - 4 T Forcingq Forcing radiative realistic shape

Interesting feedback Anomalous radiative cooling due to underlying cold boundary layer affects free trop. temperature profile. SST=23 o C,25 o C T-T0 (SCAM3) PBL top

SCM intercomparison M. Zhang Cloud profiles in the single-column versions of our 3 GCMs exhibit very similar biases to those seen in our Bony analysis of the full models. SCM +2K cloud feedbacks (not shown) also analogous to full GCMs.

Control clouds LS SHC DPC TOT Days Time Series of clouds at 900 mb liq Time Series of q tendency at 900 mb q c-e dqdt ZM HK phy Days SCAM3 equilibrium

The Cycle: ZM and Surface Turbulence – Quasi-equilibrium Evaporative cooling aloft activates PBL scheme PBL scheme kills the ZM scheme PBL scheme activates the Hack scheme The Hack scheme stabilizes itself The Hack scheme dries the air aloft Surface evaporation and the dry air aloft re-activates the ZM scheme Clouds are formed from the ZM water source

Aquaplanet climate sensitivity Meideiros/Stevens Aquaplanet simulations are simpler but show remarkably similar low-lat cloud feedbacks to full +2K Cess runs.

CAPT forecast mode analysis (Hannay/Klein) CAM3, CAM3-UW and AM2 so far. JJA 1998, GCSS NE Pacific cross-section. - EUROCS project JJA GCSS intercomparison JJA 1998/ Observations ISCCP data SSM/I product TOVS atmosphere GPCP precipitation AIRS data - Reanalyses NCEP/ERA40

Mean errors from CAM3 T42 daily forecasts Systematic biases set up fast (1 day in ITCZ, 5 days in subtropics). Can investigate cloud errors from satellite observations. (Hannay)

Clouds CPT Research Foci 1.Direct comparisons of single-column versions of the three AGCMs, LES, bulk models for idealized CTBLs, with focus on understanding climate sensitivity. 2.Improved parameterization of shallow convective cloud cover and microphysics. 3.Incorporation of an LES into a superparameterization (MMF) framework for better CTBL simulations. 4.CAPT forecast-mode and climate-mode column analysis of low-latitude CTBLs in the three GCMs. 5.Zonally symmetric aquaplanet low cloud sensitivity.