Transcript TIGGE data via OPeNDAP Jennifer M. Adams and Brian Doty IGES/COLA What is GrADS? • GrADS is an interactive tool that integrates data access,

TIGGE data via OPeNDAP
Jennifer M. Adams and Brian Doty
IGES/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
Another Example of GrADS Graphics Output
QuikSCAT Winds (HDF), Surface Obs (BUFR), and ETA Model SLP (GRIB)
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 Index
July 2009
Ensemble Forecast Time Series
(Longitude, Latitude, and Level are fixed)
Forecast Time --->
Ensemble Forecast Grid
Ensemble Member
(Longitude, Latitude, and Level are fixed)
Forecast Time --->
Ten Ensemble Forecasts
Ensemble Member
(Longitude, Latitude, and Level are fixed)
Forecast Time --->
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 --->
Ensemble Data Sets Behind GDS
• File aggregation
• Format translation
• Subset over all dimensions
• Server-side analysis
• Data become more usable and accessible
TIGGE Data Behind GDS at NCAR
+ 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 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 Monsoon
Comparison of surface observations, TRMM satellite estimates, and TIGGE forecasts
Station Observations
TRMM Estimate
ECMWF 1.5-day Forecast
All-India Precipitation (mm/day)
NCEP 1.5-day Forecast
TIGGE Forecasts of Hurricane Ike
in the Gulf of Mexico, September 2008
00z 8 Sep
12z 8 Sep
00z 9 Sep
12z 9 Sep
TIGGE Forecasts of Hurricane Ike
Init:
00z
8 Sep
Init:
12z
8 Sep
Init:
00z
9 Sep
Init:
12z
9 Sep
valid: 12z 9 Sep - 00z 13 Sep 2008
TIGGE GDS
http://cdp.ucar.edu:9090
Jennifer Miletta Adams
[email protected]