Outline

1. Coupling Climate and Hydrological ModelsInteroperability Through Web ServicesKathy Saint/SGI – NESIIJon Goodall/University of South CarolinaRichard Rood/University of Michigan Haihang You/NSF XSEDECecelia DeLuca/NOAA NESIICW2013February 20, 2013

2. Outline • Project Objective • Motivation • System Description • Components • Frameworks • System Driver • Logical Workflow • Data Flow • Architecture • Future Directions

3. Project Objectives The development of a distributed, service-based modeling system that incorporates both high performance computing and local, PC-based computing resources. Demonstration of a prototype two-way coupled system utilizing a high performance, highly parallel atmospheric model and a PC-based hydrology code used by local resource managers. Preservation of native infrastructure for both of the communities involved (climate research, water resources information delivery)

4. Motivation • Hydrological impact studies can be improved when forced with data from climate models [Zenget al., 2003; Yong et al., 2009] ; regional hydrology can affect climate. • A technology gap exists: • Many hydrological models, impacts models, and end-user services run on personal computers • Most climate models run on high performance supercomputers • Leveraging interface standards ESMF and OpenMI can mitigate the communication difficulties between these model types • ESMF contains web services interfaces that can be used to communicate across a distributed network • Both ESMF and OpenMI are widely used within their respective communities

5. System Description • Soil and Water Assessment Tool – SWAT (hydrology model) runs on PC • Community Atmosphere Model - CAM (climate model) runs on HPC • Wrappers for both SWAT and CAM provide OpenMI interface to each model • Driver (OpenMI Configuration Editor) uses OpenMI interface to timestep through models via wrappers Personal Computer Driver OpenMI SWAT CAM OpenMI Wrapper High Performance Computer ESMF Web Services • Access to CAM across the network provided by ESMF Web Services • CAM output data streamed to CAM wrapper via ESMF Web Services ESMF CAM Component

6. Components: SWAT • SWAT is a river basin scale model developed to quantify the impact of land management practices in large, complex watersheds • It was chosen for this project because it is widely used, is open source, and runs on a Windows platform

7. Components: CAM • The atmospheric model chosen for this system is the Community Atmospheric Model (CAM5), part of the Community Climate System Model (CESM1.0.3) • It was chosen because it has ESMF component interfaces, it is widely used, and it is open source

8. Frameworks: Earth System Modeling Framework • Is a high-performance, flexible software infrastructure that increases the ease of use, performance portability, interoperability, and reuse of Earth science applications • Provides an architecture for composing complex, coupled modeling systems and includes array-based, multi-dimensional data structures • Has utilities for developing individual models including utilities to make models self-describing • Web services included in the ESMF distribution allow any networked ESMF component to be available as a web service.

9. Frameworks: OpenMI • The OpenMI Software Development Kit (SDK) is a software library that provides a standardized interface that focuses on time dependent data transfer • Primarily designed to work with systems that run simultaneously, but in a single-threaded environment [Gregerson et al., 2007] • The primary data structure in OpenMI is the ExchangeItem, which comes in the form of an InputExchangeItem and an OutputExchangeItem (single point, single timestep)

10. The system driver • Controls the application flow • Implemented using OpenMI’s Configuration Editor • Convenient tool for the testing of the OpenMI implementations and model interactions

11. Hardware Architecture Personal Computer (Windows) • The Atmospheric Model runs on a HPC platform • Access to the HPC Compute Nodes must be through the Login Nodes • Access to the Login Nodes is through the Virtual Server (Web Svcs) High Performance Computer Virtual Linux Server • The Client contains the OpenMI and SWAT software, which run on a Windows platform. Login Nodes (kraken) Compute Nodes (kraken)

12. Software AchitectureClient • Configuration Editor is the driver… it is used to link the models and trigger the start of the run. • Hydrological model (SWAT 2005) is a modified version to work with OpenMI • Access to Atmospheric model (CAM) is done through “wrapper” code that accesses ESMF Web Services via an OpenMI interface Personal Computer (Windows) OpenMI Configuration Editor OpenMI SWAT 2005 CAM OpenMI Wrapper … to Web Services

13. Software ArchitectureServer HPC Login Nodes Linux Server (Web Svr) Tomcat/Axis2 Process Controller Registrar SOAP Svcs Job Scheduler • In some HPC systems, access to nodes can be restrictive. In XSEDE, only the Login Nodes can communicate with the Compute Nodes. • Access to/from external systems can be controlled via “gateway” systems using Web Services. • Running applications (such as CAM Component Svc) on Compute Nodes must be handled by a Job Scheduler. HPC Compute Nodes Comp Svc Comp Svc Comp Svc CAM CAM CAM

14. Creating a Component SvcFrom an ESMF Component • Make sure ESMF Component implements standard initialize, run and finalize routines • Modify the driver from this: • gcomp = ESMF_GridCompCreate(name=cname, rc=rc) • call ESMF_GridCompSetServices(gcomp, userRoutine=my_register_routine, rc=rc) • call ESMF_GridCompInitialize(gcomp, rc=rc) • call ESMF_GridCompRun(gcomp, rc=rc) • call ESMF_GridCompFinalize(gcomp, rc=rc) • to this: • gcomp = ESMF_GridCompCreate(name=cname, rc=rc) • call ESMF_GridCompSetServices(gcomp, userRoutine=my_register_routine, rc=rc) • call ESMF_WebServicesLoop(gcomp, portNum=27060, rc=rc) • Setup and install Process Controller, Registrar, and Web Server applications

15. Logical WorkflowOne-Way Coupling Driver SWAT/OpenMI ATM/OpenMI Wrapper ESMF Web Services ESMF Component Initialize Initialize NewClient Prepare Prepare Initialize ESMF_GridCompInitialize GetValues GetValues RunTimestep ESMF_GridCompRun GetData ValueSet ValueSet Finish Finish Finalize ESMF_GridCompFinalize Dispose Dispose EndClient

16. Logical WorkflowTwo-Way Coupling Driver SWAT/OpenMI ATM/OpenMI Wrapper ESMF Web Services ESMF Component Initialize Initialize NewClient Prepare Prepare Initialize ESMF_GridCompInitialize GetValues GetValues GetValues Extrapolate ValueSet RunTimestep ESMF_GridCompRun GetData ValueSet ValueSet Finish Finish Finalize ESMF_GridCompFinalize Dispose Dispose EndClient

17. Data FlowOne-Way Coupling High Performance Computer Personal Computer CAM/OpenMI Wrapper GetValues Output Exchange Item ESMF Component/CAM GetDataValues ESMF State SWAT/OpenMI Input Exchange Item • The data is pulled from the CAM Component to SWAT via the wrapper , initiated by the OpenMI GetValues call; this call is made once per timestep. • Data is exchanged between CAM and SWAT using the OpenMI Exchange Item structures that handle the translation from grid to point values

18. Data FlowTwo-Way Coupling High Performance Computer Personal Computer GetValues ESMF Component/CAM GetDataValues SWAT/OpenMI ESMF Export State CAM/OpenMI Wrapper Input Exchange Item ESMF Import State Output Exchange Item Import Input Exchange Item SetInputData • In two-way coupling, each model pulls the data from the other model using the OpenMI GetValues method. Extrapolation is used on the first timestep to break the deadlock between the two model requests. • OpenMI Input and Output Exchanges items are again used to exchange and translate the data. Output Exchange Item GetValues

19. Model Configurations • SWAT • Hydrology science information provided by Jon Goodall of University of S. Carolina • Lake Fork Watershed (TX) • Watershed area: 486.830 km2 • Model run: 2 years, 1977 – 1978 • Timestep = 1 day • Weather stations: • wea62 (33.03 N, 95.92 W) • wea43 (33.25 N, 95.78 W) • Export data variables: • evapotranspiration • CAM • Global atmospheric model • Model run: 1 day • Timestep: 1800 sec • Dynamical core: finite volume • Horizontal grid: 10x15 • Export data variables: • surface air temperature • precipitation • wind speed • relative humidity • solar radiation

20. Scaling Analysis • 4 areas of increasing size • 3 variations of CAM resolution (.25, .5, and 1 degree) • CAM almost always gating factor in run times • Data transfer rates minimal • 5 data values CAM to SWAT • 1 data value SWAT to CAM

21. Future Tasks • Additional SWAT configurations for larger scales • Readying the system for scientific experimentation • Currently working on replacement of CAM with WRF • Abstraction of data exchange within the ESMF wrapper code to accommodate configuration of different variables for different model implementations • Setting up SWAT as a service (running on Windows platform) so both models can be remotely accessible • Exploration of cloud computing services