NCDC, NCEP and GFDL initiated the NOAA Operational Model Archive and Distribution System.

1. Overview • To overcome a deficiency in model data access, some of the Nations top scientists are actively engaged in a framework to share data and research findings over the Internet (GEO-IDE) • NCDC, NCEP and GFDL initiated the NOAA Operational Model Archive and Distribution System. • NOMADS is a distributed data service for format independent access to climate and weather models and data.

2. NOMADS Overview • NOMADS is Operational • at NCDC • Serves 8M downloads and • 8TB per month (NCDC + • NCEP combined) • The source of model data • for many operational fcst • systems including the • private sector and the • International community nomads.ncdc.noaa.gov

3. NOMADS Available Data NWP Model • Global Forecast System (GFS), 1 and ½ degree • NCEP Spectral Statistical Interpolation (SSI) Global Data Assimilation System (GDAS) w/ restart files • North American Mesoscale (NAM, formally Eta) 1 and 3 hourly • Rapid Update Cycle (RUC) 13km and 20km • NCEP North American Regional Reanalysis (NARR) 30 years 32km • NCEP/NCAR R1/R2 Reanalysis (Climate Data Assimilation System -CDAS) • NCEP Regional Special Model (RSM) • NCEP Global Ensembles and SREF • NCEP Climate Forecast System (CFS) coupled climate model. • NCEP Ocean Wave models • NCEP Sea Ice Models • NWS Analysis of Record Real-time Mesoscale Analysis (RTMA downscaled RUC to 5km) In situ • NCDC Global Historical Climate Network (GHCN) surface temperature and precipitation anomalies • NCDC Integrated Global Radiosonde Archive (IGRA) upper air reference quality data set (formally CARDS) • NCDC Smith-Reynolds Extended Reconstructed Sea Surface Temperatures (ERSST) climatologies ) NOAA Satellite and Radar (II-III) • NODC AVHRR Pathfinder Sea Surface Temperature (SST) analysis; GOES and Radar in beta Climate Models / Coupled AOGCM • GFDL CM2.0 and CM2.1 Climate Experiments • Paleoclimate Model Intercomparison Project (PMIP) 14 Ensemble components “a” and “b” files appended.

4. Want Data? Seamless access across real-time to historical NOMADS Design PROPOSED:

5. NOMADS Uses The AWIPS-Next design paper based on NOMADS by ESRL (D. Davis)

6. NOMADS Uses Robert Rozumalski wrote: (NWS Science and Operations Officer) 9/12/06 Greetings NOMADS, I have contacted you previously regarding the RT NOMADS server and the ability of NWS Forecast offices to request subsets of the 0.5 degree GFS GRIB files for initializing local model runs. Several SOOs have asked about the availability of the NOMADS server and have commented that the server is typically saturated with users.  As I understand from our previous exchange is that the process that spatially subsets a grib file is CPU intensive and thus you limit the number of users on the system, which leads me to my request. I would like to set up a server here as a ftp2u system similar to that you have running on NOMADS that would provide data to NWS offices. The hardware is not an issue and I have good access to global GFS grib files, so what I am asking from you are the necessary ftp2u scripts (ftp2u_gfs_dir.sh) and grib file processing routines. Can you make these files available to me for this purpose? One benefit for you is that it might take some of the load off the NOMADS server but most importantly it is helping out the SOOs and field offices. Regards, Bob

7. An example of a GDS data query on Ensembles and Event Probabilities • NOMADS user client applications consist of ftp2/4u, to slice, dice and area subset repackaged GRIB files, “http” (fast ftp), partial ftp transfers, “plot” (pdisp) data display, documentation links to man and machine readable metadata descriptions of all holdings and an OPeNDAP(DODS)/GDS server. • An example the OPenDAP(DODS)/GDS server using Ensembles: • NCEP ensembles are constructed from many (14) independent model integrations by changing the initial conditions using the fastest growing global modes from 6-h forecasts. • Ensembles attempt to span the space of possible forecasts. • Ensemble members are equally probable forecasts – if not, we apply a suitable normalization. • Probability estimates are defined simply as the percentage of forecasts that satisfy a specified weather event over the total number of forecasts. • We apply this to weather elements like surface temperature, wind speed or precipitation at a location and future model forecast time periods.

8. Screen shot of the web page containing prompts and user entered responses for the probability of frost at day 4 ½. Global Ensemble model data is from both the “a” and “b” files since June/2006. The purpose of this example is to show how to make queries to the server as well as show how to directly obtain model values in an user application. We click “yes” to show the temperature queries as they are made.

9. Demonstration web page showing the URL queries of the ensembles OPeNDAP(DODS)/GDS query constrained by time and location of Stapleton airport for temperature for each ensemble component.

10. We loop the previous queries over all forecast times to 180-h and graph the result for the probabilities of frost at Denver for this forecast period. NOMADS Ensemble Probabilities on the fly: 14 model runs, 30 fcst projections 7.5-day fcsts… ONE request

11. The National Ensemble and Reanalysis Archive and Diagnostics facilityan FY07 HPC Proposal* • Leverage NOMADS partnerships and distributed Web Service technologies • A model “post-processing” facility to include both user derived diagnostic quantities from prognostic quantities; and • Access to tools to access or derive statistical bias correction information. * G. Rutledge, Z. Toth & J. Alpert

12. National Academies Recommendation • “The NOAA National Operational Model Archive and Distribution System (NOMADS) should be maintained and extended to include (a) long-term archives of global and regional ensemble forecasting systems and their native resolution, and (b) re-forecast datasets to facilitate post-processing”. National Research Council of the National Academies, Board of Atmospheric Science and Climate, (2006), “Completing the Forecast: Characterizing and Communicating Uncertainty for Better Decisions Using Weather and Climate Forecasts”, Recommendation 3.4, pp76, October 2006 National Academies Press

13. Pilot for TIGGE? • Proposal includes NAFES access leading to distributed remote access for • a single point of access to historical analysis (initial conditions), historical forecasts, and all the associated verifying observations. • Hindcasts • NOMADS will have NCEP Global and Regional datasets available irrespective of HPC Proposal.

14. For Further Information Glenn.Rutledge@noaa.gov Jordan.Alpert@noaa.gov nomads.ncdc.noaa.gov Rutledge, G.K., J. Alpert, and W. Ebisuzaki, 2006: NOMADS, a climate and weather model archive at the National Oceanic and Atmospheric Administration. Bulletin of the American Meteorological Society, 87 (3), 327-341, (March 2006)