Post on 27-Mar-2015
transcript
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