TIGGE data via OPeNDAP Jennifer M. Adams and Brian Doty IGES/COLA.

TIGGE data via OPeNDAP

Jennifer M. Adams and Brian DotyIGES/COLA

What is GrADS? • GrADS is an interactive tool that integrates

data access, analysis, and visualization• Handles many data formats:

Binary, NetCDF, HDF, GRIB, BUFR • Two data models for gridded and in situ data• Expression handling is flexible, compact, recursive• Programmable interface for scripting• Written in C; code is open source (GPL)• Active users forum with 1800+ subscribers

GOES VIS Image with Radar, 500mb Heights, and SLP

18z 4 June 2009

Analysis of Surface METAR Observations with Radar

18z 29 May 2009

QuikSCAT Winds (HDF), Surface Obs (BUFR), and ETA Model SLP (GRIB)

Another Example of GrADS Graphics Output

00z 6 Dec 2003

What is the GrADS Data Server?

• GDS is a stable, secure, OPeNDAP data server that provides subsetting and server-side analysis services over the internet

• GDS can serve any GrADS-readable dataset, and unifies all data formats into a NetCDF framework

• Open a data set with http://server/filename instead of /disk/filename

News from GrADS/GDS Team GrADS has a 5th grid dimension for ensembles set X, Y, Z, T, or E set lon, lat, lev, time, or ens

GrADS has an interface for HDF5 and GRIB2 GDS can serve any GrADS data set GrADS is a client for any OPeNDAP data set GrADS supports GIS-compatible formats GeoTIFF, KML, and ESRI Shapefiles

GrADS Plot in Google Earth

Palmer Drought Severity IndexJuly 2009

Ensemble Forecast Time Series (Longitude, Latitude, and Level are fixed)

Forecast Time --->

Ensemble Forecast Grid (Longitude, Latitude, and Level are fixed)

Forecast Time --->

Ens

embl

e M

embe

r

Ten Ensemble Forecasts (Longitude, Latitude, and Level are fixed)

Forecast Time --->

Ens

embl

e M

embe

r

Ensemble Forecast Time Series (Longitude, Latitude, and Level are fixed)

Forecast Time --->

Ensemble Mean = tloop(ave(Z,e=1,e=21))Ensemble Min/Max = tloop(min(Z,ens=c00,ens=p20)) +/- StdDev of Ensemble Mean = tloop(sqrt(ave(pow(Z-Zave,2),e=1,e=21)))

Forecast Time --->

• File aggregation • Format translation• Subset over all dimensions• Server-side analysis• Data become more usable and accessible

Ensemble Data Sets Behind GDS

+ Perfect testbed for ensemble handling and GRIB2 interface+ Boost to usage of TIGGE data+ Forecasts organized by date and by provider+ Time series of analyses

- Nearly unbearable load on old hardware- 48-hour data embargo- Int’l agreement requires password protection

TIGGE Data Behind GDS at NCAR

TIGGE Multi-Member Multi-Model Ensemble 500mb Geopotential Height valid August 30, 2008

7-day Lead

3-day Lead

5-day Lead

1-day Lead

2008 Indian MonsoonComparison of surface observations, TRMM satellite estimates, and TIGGE forecasts

TRMM EstimateStation Observations ECMWF 1.5-day Forecast NCEP 1.5-day Forecast

All-India Precipitation (mm/day)

TIGGE Forecasts of Hurricane Ikein the Gulf of Mexico, September 2008

00z 8 Sep

12z 8 Sep

00z 9 Sep

12z 9 Sep

TIGGE Forecasts of Hurricane Ike valid: 12z 9 Sep - 00z 13 Sep 2008

Init:00z

8 Sep

Init:12z

8 Sep

Init:00z

9 Sep

Init:12z

9 Sep

TIGGE GDS http://cdp.ucar.edu:9090

Jennifer Miletta Adams jma@iges.org