Metadata for the Coupled Ocean/Atmosphere Mesoscale

Prediction System (COAMPS)using the

Earth System Modeling Framework (ESMF)

Peter BoslerUniversity of MichiganNCAR SIParCS Program

August 4, 2009

Outline

• SIParCS Project – Sylvia Murphy, NCAR ESMF– Tim Campbell, Navy Research Lab. Stennis Space Center MS

• COAMPS Overview• Why ESMF?

– NUOPC– Metadata

• Project Results and Applications– Using COAMPS Metadata (internal & external)

SIParCS Project

• Describing Models– Add Metadata attributes to COAMPS

• Fields have Name, StdName, and Units attached• Components have Model Name, Version, Coding Language, Web URL,

etc.. attached• Export metadata in XML format for each component

• Automating Models– ESMF already has coupling functions like parallel regridding – My job: Build an ESMF Attribute-based unit converter

• Use attributes to decide if conversion is necessary• Perform the conversion using Unidata’s UDUnits• Update the attributes to reflect conversion

COAMPS Basics• “Coupled Ocean/Atmosphere Mesoscale Prediction System”• Standard Navy model for “On-Demand” forecasting• Regional weather prediction out to 72 hours (operational)• High resolution, non-hydrostatic model

Motivation

• Earth System Modeling Framework– Chosen as Common Model Architecture and model-to-model interface

standard by National Unified Operational Prediction Capability (NUOPC)

– Facilitates modularity and flexibility by providing user-defined methods to couple independent components

• Metadata – Formally structured information with a controlled vocabulary

embedded within the model itself, i.e., the ESMF Attribute class.– ESMF includes NUOPC recommended metadata capabilities– Metadata allows model components to be “self-describing”

• Components– Gridded Components

• Atmosphere Component, Ocean Component, Wave Component • Run on separate PETs in distributed environment

– Coupler Components• Handle communication between Grid. Comps.

– COAMPS uses 5 ESMF Gridded Components

• States– Import/Export– Basic data structure for coupler communication

• Fields/Field Bundles– Data and Grid in one package– Field Bundles are collections of fields that share the same grid

ESMF Terminology

ESMF Metadata

• ESMF “Attributes” implement standard ontologies such as the NetCDF Climate and Forecast Convention (CF)

• Attributes can be attached to most ESMF objects (i.e., Components, Field Bundles, Fields, etc.)

• Mechanism for fast search capability of both models and their datasets via online data portals (External Usage)

• Mechanism for component to component communication through an ESMF coupler (Internal Usage)

SIParCS Project (Part 1)

• Built ESMF & COAMPS on Bluefire– ESMF 4.0 beta snapshot 6– COAMPS Version 4

• Modified COAMPS code to include ESMF Attributes– Fields & States– Components (Atmosphere, Ocean, Wave, Ocean Bkgd, Wave Bkgd)– Linked Components to associated States and Fields

• Export COAMPS metadata XML

Sample XML Output

Sample XML Output

Internal Usage Example

Coupler

Ocean ExportAtmos. Import

During Initialize Phase, Coupler detects difference in attributes of the SST field between two components.

Attributes of SST Export are degrees Celsius

Attributes of SST import are degrees Kelvin

Internal Usage Example

Coupler

Ocean ExportAtmos. Import

Run Phase : Coupler receives Ocean SST data from Ocean Comp. in Celsius

RunPhase:Export SST in °C

Internal Usage Example

Coupler

Atmos. ImportOcean Export

Run Phase: Coupler performs unit conversion to Kelvin using UDUnits and updates Field Attribute

Internal Usage Example

Coupler

Atmos. ImportOcean Export

Run Phase: Coupler sends converted SST Field to Atmos. Comp.

Atmos. Comp. receives SST field in °K

ESMF Superstructure

ESMF Infrastructure

•COAMPS Atmos. Comp.

Atmos.

•COAMPS Ocean Comp.

Ocean

•Wave Watch 3Wave

Data Manipulation (Regridding, unit conversion, etc.)

Data Transfer (Import/Export States, Fields & Field Bundles, and Metadata)

SWAN

SIParCS Project (Part 2)

• Get to know UDUnits– UDUnits 2.1.8– C library/API– XML database

• How to use UDUnits in ESMF?– Overlap with ESMF_Attributes– Error checking capability– Parallelization / numeric efficiency

• Write and test ESMF Physical Units module– In progress…

Summary

• ESMF is becoming the technical basis for operational numerical weather prediction

• COAMPS is an example of “modular modeling” using ESMF through component interoperability

• ESMF:– http://www.esmf.ucar.edu/

• COAMPS:– http://www.nrlmry.navy.mil/coamps-web/web/home

• UDUnits:– http://www.unidata.ucar.edu/software/udunits/