C. R. Mechoso (1), Gabriel Cazes-Boezio (1, 3),

1. Experimental El Niño/Southern Oscillation Predictions by the UCLA Atmospheric General Circulation Model (GCM) Coupled to the MIT and POP Oceanic GCMs using the Earth System Model Framework (ESMF) C. R. Mechoso (1), Gabriel Cazes-Boezio (1, 3), J. A. Spahr (1), D. Menemenlis (2), and S.J. Zhou (4) Dept. Atmospheric and Oceanic Sciences, UCLA, USA NASA/Caltech Jet Propulsion Laboratory, USA On leave from IMFIA, Universidad de la Republica, Uruguay Software Integration and Visualization Office, NASA/GSFC and Northrop Grumman This talk presents the first independent adoption of ESMF technology.

2. Atmospheric General Circulation Model (AGCM) Atmospheric Chemical Tracer Model (ACTM) Data Broker Oceanic General Circulation Model (OGCM) Oceanic Chemical Tracer Model (OCTM) UCLA Earth System Model • Model components: • • UCLA Atmospheric GCM • • LANL Parallel Ocean Program (POP) • • UCLA ACTM (which can include up to 64 species) • • Simple NASA/JPL Ocean Chemical Transport Model • Distributed Data Broker

3. Increasing the Interoperability of an Earth System Model: Atmospheric-Ocean Dynamics and Tracer Transports NCC4-624C. R. Mechoso, PI • Major thrusts of the project: • to further our understanding of an ability to predict the dynamic interaction of physical and chemical processes affecting Earth • to incorporate the use of NASA data and highlight its importance • to demonstrate interoperability of codes used in the community of Earth Science.

4. UCLA AGCM - MIT OGCM

5. UCLA AGCM - MIT OGCM

6. UCLA AGCM - LANL POP

7. UCLA AGCM - LANL POP

8. Atmospheric General Circulation Model (AGCM) Atmospheric Chemical Tracer Model (ACTM) Data Broker ESMF Oceanic General Circulation Model (OGCM) Oceanic Chemical Tracer Model (OCTM) UCLA Earth System Model Model components: • UCLA AGCM with upgraded PBL parameterization • LANL Parallel Ocean Program (POP) and MIT OGCM, both in a quasi-global domain with the same grid. • UCLA ACTM (which can include up to 64 species) • Simple NASA/JPL Ocean Chemical Transport Model

9. Porting Strategy • Model codes (AGCM, OGCM) were restructured to isolate Initialize, Run and Finalize tasks (i.e., were made ESMF compliant) • An ESM Driver Program (EDP) was created to control the sequence in which those Initialize-Run-Finalize tasks and data transfers are executed, as well as to keep track of simulation time.

10. Coupled Atmosphere-Ocean Application in ESMF- Superstructure ESM Application AGCM App OGCM App Atmos to Ocean Coupler Ocean to Atmos Coupler Initialize Run Finalize Initialize Run Finalize MIT OGCM POP OGCM UCLA AGCM Import/Export States Import/Export States Infrastructure

11. The difference in prediction between with and without ESMF is possibly due to the different regridding methods --- to be verified!

12. Generic Coupler in ESMF Observation: couplers for UCLA AGCM/LANL OGCM and for UCLA AGCM/MIT OGCM are almost identical

13. Issues in Coupling Model Components(e.g., From Ocean to Atmosphere) export import export import Atmo Init1_a(…) Init2_a(…) Run_a(…) Final_a(…) ssta Sst_o Ocean Init1_o(…) Init2_o(…) Init3_o(…) Run_o(…) Final_o(…) ua S_o va Coupler Regrid(…) U_o V_o Sea_o F_o • Function names in model components are different: • ESMF’s solution: • Uses three standard functions with a stage option, initialize, run, and finalize • Use a function registration service, setEntryPoint and setService • The names of import variables of a “use” component are different from those of export variables of a “provide” component. • The number of import variables of a “use” component are different from that of export variables of a “provide” component.

14. Generic Coupler: design(automatically name mapping and regridding) CF name pointer neededsource field Destination field Atmo Ssta T_surf ssta Ptr_Ssta Ua Atmos Sst_o ssta U_surf ua Ptr_ua Va register U_o ua V_surf va Ptr_va V_o va Match name T_surf Sst_o Ptr_Sst_o S_surf S_o Ptr_S_o remake export state Output import state Ocean U_surf U_o Ptr_U_o V_surf V_o Ptr_V_o Ptr_Sst_o regrid Ptr_Ssta Sea_level Sea_o Ptr_Sea_o Ptr_U_o Ptr_ua frazil F_o Ptr_F_o Ptr_V_o Ptr_va For the case of only interpolation operation is needed.

15. SUMMARY • The coupled atmosphere-ocean model shows skill in ENSO prediction from six months in advance. The skill is higher for the UCLA AGCM/MIT OGCM combination. • The UCLA AGCM was coupled to the MIT OGCM and LANL POP using ESMF services. • The most time demanding task was to make the model components ESM compliant. • Much more work with the ESMF is needed for debugging, increased capability and user friendliness. • Model codes integrated into the ESMF require maintenance if the framework is to become a standard for Earth System Modeling.

16. Project Organization • Tier I: Upgrade the UCLA Earth System Model (ESM). The principal upgrades are in the planetary boundary layer (PBL) parameterization of the AGCM and domain extension of the OGCM. Perform ENSO predictions. • Tier II: Address issues of code interoperability by using the ESMF services to couple the UCLA AGCM with either LANL POP or the MIT OGCM and by performing forecasts of El Niño/Southern Oscillation (ENSO). • Tier III: Assess the impact of NASA data by comparing ENSO forecasts using initial states provided by JPL’s ECCO project (http://ecco.jpl.nasa.gov). The MIT OGCM is a component in the ECCO’s data assimilation system, while POP is not.

17. The AGCM as ESMF Compliant Module AGCM_GridComp AGCM_Initialize AGCM_Run(start time, end time) AGCM_Finalize

18. ESM Application Register components Create data bases Initialize components Call gridded components drivers (time advance) Call coupler components for regridding and transfers Call gridded components to perform finalize functions

19. Component Driver in EDP (e. g., AGCM) Create ESMF grid Create fields and attach them to import/export states Read control files Set up node distribution Retrieve SST from import state Advance in time Strore updated fields in export state Clean up and close communications

20. Modeling Focus: PBL in UCLA AGCM Traditional Framework Suarez et al. (1983) Revised Framework Konor and Arakawa (2005)

21. Coupler AGCM OGCM CPL Ctrl Time execution E I OGCM Exec AGCM Exec Data Fields Data Fields CPL Ctrl E I Data Reference I Import State Data Flow E Export State

22. “Double ITCZ” Problem Hypothesis 1: Poor heat transport by ocean eddied from upwelling regions - Insufficient OGCM resolution? Hypothesis 2: Poor simulation of the zonal circulation - Difficulties in the simulation of resolved and subgrid processes? Annual Mean SST Model Observation UCLA AGCM - MIT OGCM

23. ESMF Class Structure ApplicationComponent GriddedComponent CouplerComponent Superstructure State Bundle Regrid Infrastructure Field Grid PhysGrid DistGrid F90 Data Communications Layout Array Comm Route C++ MachineModel Utilities: TimeMgr, Config, LogErr, I/O etc.

24. ESMF Component Registration Components provide a single externally visible entry point, which register the other entry points with the ESMF. Components can: • Register one or more Initialization, Run, Finalize, and Checkpoint entry points. • Register a private data block which can contain all data associated with this instantiation of the Component. Higher level Comp ESMF Framework Services cmp_final() cmp_register() cmp_run() cmp_init() Public subroutine Private subroutine

25. Coupler ComponentsImport/Export States The AGCM does not have access to the internals of the OGCM, and vice versa. The exchange data is through a coupler component, which exchanges the roles of Export State from one component to Import State for the other component. The coupler components also do the grid transformations. coupler ocn_component subroutine ocn_run(comp, & ImportState,ExportState, Clock, rc) atm_component subroutine atm_run(comp, & ImportState,ExportState, Clock, rc)