Implementation of Model Data Interoperability for IOOS:

Successes and Lessons Learned

Rich Signell USGS Woods Hole, MA / NOAA Silver Spring USA

Model Data Interoperability

is Low-Hanging Fruit!

US Integrated Ocean Observing System (IOOS®)

IOOS® Plan defines:• Global Component• Coastal Component

17 Federal Agencies 11 Regional Associations

HF radar

DMAC approved services for Gridded Data and Model Outputs

Table ofContents

Metadata

Data Values

DataProvider

CF Metadata

QualityControl

satellite

griddedmodeloutputs

OGC WCS(Web

CoverageService)

OPeNDAP/CF

The Problem: Stovepiped Model Access

UCLA/JPL ROMS SCB Model Yi Chao, JPL

ChesROMS Model Wen Long, UMaryland

Result: Inability to compare and assess model results & underutilization of model products

The GoMOOS Nowcast/Forecast Circulation Model (University of Maine)

Issue: Ocean grids are not regularly spaced!

Stretched surface and terrain following vertical coordinates

Curvilinear orthogonal horizontal coordinates

Climate and Forecast (CF) Metadata Conventions

Groups adopting CF:GO-ESSP: Global Organization for Earth System Science Portal IOOS-DMAC: Integrated Ocean Observing SystemESMF: Earth System Modeling FrameworkOGC: Open Geospatial Consortium (via WCS netcdf encoding)

CF-Compliant Ocean Model Files_rho:standard_name = "ocean_s_coordinate" ;s_rho:formula_terms = "s: s_rho eta: zeta depth: h a: theta_s b: theta_b depth_c: hcs_rho:field = "s_rho, scalar" ;

double s_w(s_w) ;s_w:long_name = "S-coordinate at W-points" ;s_w:valid_min = -1. ;s_w:valid_max = 0. ;s_w:standard_name = "ocean_s_coordinate" ;s_w:formula_terms = "s: s_w eta: zeta depth: h a: theta_s b: theta_b depth_c: hc" ;s_w:field = "s_w, scalar" ;

float salt(ocean_time, s_rho, eta_rho, xi_rho) ;salt:long_name = "averaged salinity" ;salt:units = "PSU" ;salt:time = "ocean_time" ;salt:coordinates = "lat_rho lon_rho" ;salt:field = "salinity, scalar, series" ;

float temp(ocean_time, s_rho, eta_rho, xi_rho) ;temp:long_name = "averaged potential temperature" ;temp:units = "Celsius" ;temp:time = "ocean_time" ;temp:coordinates = "lat_rho lon_rho" ;temp:field = "temperature, scalar, series" ;

float u(ocean_time, s_rho, eta_u, xi_u) ;u:long_name = "averaged u-momentum component" ;u:units = "meter second-1" ;

NetCDF Java Library

NcML XML markup language for NetCDF

<aggregation dimName="time" type="joinExisting"> <netcdf location="http://rocky.umeoce.maine.edu/cdfs/gomoos.20050509.cdf" /> <netcdf location="http://rocky.umeoce.maine.edu/cdfs/gomoos.20050510.cdf" /> </aggregation> <variable name="elev"> <attribute name="coordinates" value="x y" /> </variable> <variable name="depth"> <attribute name="coordinates" value="x y" /> </variable> <variable name="temp"> <attribute name="coordinates" value="x y zpos" /> </variable> <variable name="time"> <attribute name="units" value="days since 2002-01-01 00:00 UTC" /> </variable> <variable name="zpos"> <attribute name="standard_name" value="ocean_sigma_coordinate" /> <attribute name="formula_terms" value="sigma: zpos eta: elev depth: depth" /> <attribute name="positive" value="up" /> <attribute name="units" value="1" /> <attribute name="axis" value="Z" /> <values> 0 -0.002 -0.004 -0.008 -0.016 -0.024 -0.032 -0.04 -0.06 -0.08 -0.10 -0.12 -0.14 -0. </variable> <attribute name="Conventions" value="CF-1.0" />

Data Interoperability Model

NJ Toolkit for Matlab http://njtbx.sourceforge.net

• Objective: Make it simple to access CF data• Example function:• [t, geo]=nj_tslice(URI,’temp’,1);• t = 22x120x180 single• geo =

– lat: [120x180 single] – lon: [120x180 single]– z: [22x120x180 double]– time: 733582 (matlab datenum)

• nj_tslice works identically for ROMS, POM, ECOM, WRF, Wavewatch3

• URI can be: local NetCDF, remote NetCDF, NcML, OpenDAP Data URL

• Coding by Sachin Kumar Bhate MSSTATE

Comparing Models with Data in Matlab

Model 1: UMASS-ECOM Model 2: UMAINE-POM Data: SST 2008-Sep-08 07:32

Buoy_comp.m: Model/Data comparison of Wave Height

Browser-based Mapping with ncWMS/Godiva2

3D Visualization with the Integrated Data Viewer (IDV)

Single Point of Access Catalog:GEO-IDE => IOOS Regions

http://ferret.pmel.noaa.gov/thredds/geoideCatalog.html

Working with Data in ArcGIS using the NOAA/ASA Environmental Data Connector

14 Different Ocean Forecast Models Spanning CONUS Waters in IDV

OOI-CI OSSE (Sep-Oct, 2009)

Models being used for BP Spill

Successes

• Existing Unidata technology allowed for standards-based delivery of aggregated geospatial data from native model grids that put little or no effort on the data provider

• Demonstrated interoperability with 17 THREDDS servers in 11 IOOS Regions

• What did we get? – Single point of access for regional model results– Interoperable software– More eyes on the model results– More usage of model results– Faster feedback to modelers– Improved models– Increased community support for standards-based access

What Next?

• Continue work on a high-level scientific toolbox for standardized access to model data. (Matlab toolbox based on NetCDF-Java)

• Develop unstructured grid support: Common Data Model implemented in NetCDF-Java with methods comparable to structured grid

• Applications need to be modified to read standardized data via OPeNDAP instead of home-grown files

• Work on discovery and documentation

Lessons Learned

• Honor the existing practices• Users are best served by developing

infrastructure for Developers• Focus on success: find something that works,

clone it, and build off it

Questions, Feedback?

Dr. Richard P. Signell+1 (508) 457-2229

rsignell@usgs.gov

Role of Regions

• Develop customized THREDDS catalogs for regional users

• Report status of services (e.g. NetCheck)• Assess and help with gridded data standards

compliance following UAF-developed techniques

• Develop end-user applications that access gridded data, using CF-compliant OPeNDAP

• Help educate regional scientists, developers, consultants that standardized services, libraries and tools are available

Late Breaking News

THREDDS

• When people say “THREDDS”, they can mean a catalog or a data server– THREDDS Catalogs are XML files that define

metadata, datasets and services– THREDDS Data Server is a Java data server

application developed by Unidata, a simple and flexible way for delivering CF-compliant data via OPeNDAP

OPeNDAP

• When people say “OPeNDAP”, they can mean protocol, a server, or an organization– OPeNDAP (or just DAP) protocol: a remote data

access service protocol with multiple responses• DDS – describes the format of the data• DAS – describes associated attributes• DDX – XML response containing the DDS & DAS• DODS – the actual data

– OPeNDAP server: a server capable of serving the DAP protocol (e.g. THREDDS Data Server, Hyrax, Pydap, GrADS Data Server)

– OPeNDAP organization: Defines and maintains the DAP protocol, develops servers and clients, provide custom OPeNDAP solutions