Transferability as a Strategy for Researching the Water Cycle and Energy Budget E. S. Takle1, J. Roads2, W. J. Gutowski, Jr.1, B. Rockel3, R. W. Arritt1, and I. Meinke2 1Iowa State University, Ames, IA 2Scripps Institution of Oceanography, UCSD,LaJolla, CA 3GKSS Research Centre, Geesthacht , Germany gstakle@iastate.edu

“Transferability” is proposed as the next step beyond “model intercomparison projects” (MIPs) for advancing our understanding of the global energy balance and the global water cycle by use of models

Model Intercomparison Projects ARCMIP GLIMPSE BALTIMOS GKSS/ICTS PRUDENCE SGMIP QUIRCS RMIP PIRCS IRI/ARC AMMA LA PLATA

Lessons Learned from MIPs No single model stands out as being best at simulating all variables Most MIPs have helped individual modelers identify specific shortcomings of their models Regional models run in climate mode simulate real sequences of events if such events are strongly coupled to the large-scale flow (stratiform precip vs. convective precip)

Lessons Learned… MIP ensemble means frequently are closer to observations than any individual model MIP ensembles recognize extreme events but fail to capture the magnitude of such extremes Models generally capture well the diurnal and seasonal cycles of temperature, although with larger error under extreme cold and stably stratified surface conditions (ARCMIP)

Lessons Learned… Most models produce too many high-level clouds, too few mid-level clouds, and too many low clouds There is wide disagreement on partitioning between convective and stratiform precipitation even when precipitation totals agree Some but not all models can capture the diurnal cycle of precipitation even with nocturnal convection All models tend to produce to many light rain events and not enough high-intensity rain events

Lessons Learned… All models (with 50 km resolution) fail to capture the timing between maximum and minimum 3-hourly precipitation accumulation from MCSs Seasonal cycles of precipitation are captured over a wide range of climate regimes Precipitation generally is underestimated in both extreme events and very moist climates

Transferability Objective Regional climate model transferability experiments are designed to advance the science of high-resolution climate modeling by taking advantage of continental-scale observations and analyses.

Objective Regional climate model transferability experiments are designed to advance the science of high-resolution climate modeling by taking advantage of continental-scale observations and analyses. MIPs have helped modelers eliminate major model deficiencies. Coordinated studies with current models can advance scientific understanding of global water and energy cycles.

Use of Regional Models to Study Climate How portable are our models?

Use of Regional Models to Study Climate How portable are our models? How much does “tuning” limit the general applicability to a range of climatic regions?

Use of Regional Models to Study Climate How portable are our models? How much does “tuning” limit the general applicability to a range of climatic regions? Can we recover some of the generality of “first-principles” models by examining their behavior on a wide range of climates?

Transferability Working Group (TWG) Overall Objective To understand physical processes underpinning the global energy budget, the global water cycle, and their predictability through systematic intercomparisons of regional climate simulations on several continents and through comparison of these simulated climates with coordinated continental-scale observations and analyses

Types of Experiments Multiple models on multiple domains (MM/MD) Hold model choices constant for all domains

Types of Experiments Multiple models on multiple domains (MM/MD) Not Hold model choices constant for all domains Not Single models on single domains Single models on multiple domains Multiple models on single domains

TRANSFERABILITY EXPERIMENTS FOR ADDRESSING CHALLENGES TO UNDERSTANDING GLOBAL WATER CYCLE AND ENERGY BUDGET ARCMIP GLIMPSE BALTEX BALTIMOS BALTEX GKSS/ICTS PRUDENCE MAGS SGMIP QUIRCS RMIP PIRCS CAMP GAPP GAPP GAME GAME LBA LBA IRI/ARC AMMA CATCH MDB LA PLATA MDB

Specific Objectives of TWG Provide a framework for systematic evaluation of simulations of dynamical and climate processes arising in different climatic regions

Specific Objectives of TWG Provide a framework for systematic evaluation of simulations of dynamical and climate processes arising in different climatic regions Evaluate “transferability”, that is, quality of model simulations in “non-native” regions

Specific Objectives of TWG Provide a framework for systematic evaluation of simulations of dynamical and climate processes arising in different climatic regions Evaluate “transferability”, that is, quality of model simulations in “non-native” regions “Meta-comparison” among models and among domains

We recognize that… The water cycle introduces exponential, binary, and other non-linear processes into the climate system

We recognize that… The water cycle introduces exponential, binary, and other non-linear processes into the climate system Water cycle processes occur on a wide range of scales, many being far too small to simulate in global or regional models

We recognize that… The water cycle introduces exponential, binary, and other non-linear processes into the climate system Water cycle processes occur on a wide range of scales, many being far too small to simulate in global or regional models The water cycle creates spatial heterogeneities that feed back strongly on the energy budget and also the circulation system

Strategy Identify key processes relating to the water cycle and energy budget that express themselves to different degrees in different climatic regions

Strategy Identify key processes relating to the water cycle and energy budget that express themselves to different degrees in different climatic regions Create hypotheses that can be tested by use of MM/MD experiments. Candidate examples: “Seasonally dependent biases in cloudiness are due primarily to errors relating to soil moisture” “Physical parameterizations connected with the water cycle are the largest source of error in simulating the diurnal temperature cycle”

Expected Outcomes Improved understanding of the water cycle and its feedbacks on the energy budget and circulation system

Expected Outcomes Improved understanding of the water cycle and its feedbacks on the energy budget and circulation system Improved capability to model climate processes at regional scales

Expected Outcomes Improved understanding of the water cycle and its feedbacks on the energy budget and circulation system Improved capability to model climate processes at regional scales Improved applicability to impacts models

Plan of Work Phase 0: Write an article for BAMS summarizing lessons learned from various “MIPs” and describe how transferability experiments will provide new insight on the global climate system, particularly the water cycle and energy budget, report preliminary results

Plan of Work Phase 0: Write an article for BAMS summarizing lessons learned from various “MIPs” and describe how transferability experiments will provide new insight on the global climate system, particularly the water cycle and energy budget, report preliminary results Phase 1: Conduct pilot studies

Plan of Work Phase 0: Write an article for BAMS summarizing lessons learned from various “MIPs” and describe how transferability experiments will provide new insight on the global climate system, particularly the water cycle and energy budget, report preliminary results Phase 1: Conduct pilot studies Phase 2: Perform sensitivity studies on key processes relating to the water cycle. Create and test hypotheses by MM/MD

Plan of Work Phase 0: Write an article for BAMS summarizing lessons learned from various “MIPs” and describe how transferability experiments will provide new insight on the global climate system, particularly the water cycle and energy budget, report preliminary results Phase 1: Conduct pilot studies Phase 2: Perform sensitivity studies on key processes relating to the water cycle. Create and test hypotheses by MM/MD Phase 3: Prediction, global change, new parameterizations

Models: Use experience gained from simulating “home domains” Transferability Consolidates Lessons Learned from Modeling and Observations Models: Use experience gained from simulating “home domains”

Models: Use experience gained from simulating “home domains” Transferability Consolidates Lessons Learned from Modeling and Observations Models: Use experience gained from simulating “home domains” CEOPS: Use dominant features of the water cycle and energy budget of each CSE to generate testable hypotheses Review what has been learned Identify unique climate features

Transferability Experiments Meet GEWEX Phase II Objectives: “Produce consistent descriptions of the Earth’s energy budget and water cycle…”

Transferability Experiments Meet GEWEX Phase II Objectives: “Produce consistent descriptions of the Earth’s energy budget and water cycle…” “Enhance the understanding of how the energy and water cycle processes contribute to climate feedback”

Transferability Experiments Meet GEWEX Phase II Objectives: “Produce consistent descriptions of the Earth’s energy budget and water cycle…” “Enhance the understanding of how the energy and water cycle processes contribute to climate feedback” “Develop parameterizations encapsulating these processes and feedbacks for atmospheric circulation models”

Current Status Three models (RSM/Scripps, Lokalmodell/GKSS, RegCM3/ISU) simulating four domains (GAPP&MAGS - North America, MDB - Australia, LBA - South America, and BALTEX - Europe)

Current Status Three models (RSM/Scripps, Lokalmodell/GKSS, RegCM3/ISU) simulating four domains (GAPP&MAGS - North America, MDB - Australia, LBA - South America, and BALTEX - Europe) More collaborating modeling groups are being sought

Current Status Three models (RSM/Scripps, Lokalmodell/GKSS, RegCM3/ISU) simulating four domains (GAPP&MAGS - North America, MDB - Australia, LBA - South America, and BALTEX - Europe) More collaborating modeling groups are being sought Contact E. S. Takle (gstakle@iastate.edu)

Transferability Domains and CSE Reference Sites