1. ESMF adoption in CCSM First steps: getting to ESMF-compliant data components. August 25, 2008

2. MCT interface Native data structures BaselineA for steps 1 and 2: Use dead atm component INFO_DEBUG set to 2 in driver namelist. Values of global integrals in the coupler log file are the baseline. Block arrows represent a data structure conversion, plain arrows information transfer. Driver Dead Component MCT data and infodata

3. Driver Dead Component MCT interface Native data structures First step: Inside the dead component 1. MCT to ESMF conversion. 2. ESMF to MCT conversion. During run-time: Infodata is updated between components inside the driver. Driver passes updated infodata to dead component. Dead component updates specific values of infodata locally. Verification: Confirm global integrals are bit for bit against baselineA. ESMF data and infodata MCT data and infodata

4. ESMF interface Native data structures Second step: 1.Remove MCT to ESMF conversion in the dead component. 2.Put ESMF interface on the dead component. 3.MCT to ESMF conversion and update routines move to a comp converter that is called in a layer outside the ESMF interface, sits in new esmf_share code directory During run-time: Infodata is updated inside the driver. Driver passes updated infodata to comp converter. Comp converter updates specific values of infodata locally. Verification: Confirm global integrals are bit for bit against baselineA. MCT data and infodata ESMF data and infodata Driver Dead Component MCT interface comp converter MCT data and infodata

5. MCT interface Native data structures BaselineB for steps 3 and 4: Using data atm component INFO_DEBUG set to 2 in driver namelist. Values of global integrals are the baseline. We are here. Driver Data Component MCT data and infodata

6. ESMF interface Native data structures Third step: 1.Run with data components. 2.Put ESMF interface on the data component. 3.Use comp converter approach from second step. During run-time: Infodata is updated inside the driver. Driver passes updated infodata to comp converter. Comp converter updates specific values of infodata locally. Verification: Confirm global integrals are bit for bit against baselineB. MCT data and infodata ESMF data and infodata Driver Data Component MCT interface comp converter MCT data and infodata

7. ESMF interface Native data structures Fourth step: 1.Remove ESMF to MCT conversion inside the data component. 2.Do direct translation of ESMF to native data structures. During run-time: Infodata is updated inside the driver. Driver passes updated infodata to comp converter. Comp converter updates specific values of infodata locally. Verification: Confirm global integrals are bit for bit against baselineB. At the end of this step the data atm will contain a valid ESMF component. ESMF data and infodata Driver Data Component MCT interface comp converter MCT data and infodata