# Presentation: 692000

## North American Regional Reanalysis

-              (NARR) Update

- Mesoscale Branch Meeting, 10 March 2005

## Our output files produced  (about 75 Tb total):

- Six sets of reanalysis files, at 3 hr intervals each:
- • “Restart files”: on “native” (model) grid, all variables needed to restart the model;
- •  On the “native” (E) grid, but interpolated to p levels:
- 		Analysis files,		First guess files;
- •  Interpolated in addition to Grid 221 (Lambert, “AWIPS”):
- 		Analysis files,		First guess files;
- •  “Merged” files: Grid 221, a selection of (mostly) analysis variables, enhanced by, e.g., fluxes (“fcst”, from 1st guess), 3-h averages, and 3-hr accumulations (4 types of time validity)

## Output files produced

- •  Input observations;
- •  Climatological and fixed fields used;
- •  Various plots;
- •  Special subsets:
- 	-  Land-surface subset - fields related to
- 		land-surface/hydrology modeling
- 	-  Climatological subset (CPC)
- •  “Free forecasts” (“reforecasts”): 3-day forecast 	every 2.5 days

## Output files produced, cont’d;                              more on the merged files:

- •  Two main sets of the merged files produced; so-called merged-a and merged-b;
- •  Temporal frequency 3 hour (8 files per day, archived in a single tar file)
- •  Merged-a daily tar file is about 450 Mb, merged-b about 75 Mb;
- •  Horizontal grid standard NCEP grid 221 (Lambert conformal, 32 km).  Note that a sliver of 221 is sticking out of the RR domain/ variables undefined;
- •  In vertical: pressure levels, "hybrid levels” (lowest eta mid-layers), soil layers, boundary layer etc.;
- •  Fields in merged-a files mostly analysis; some 3-hr accumulations, 3-hr averages, and 3-hr forecasts;
- •  When the same filed is output as analysis and 3-hr forecast, 3-hr forecast is placed in merged-b file (grads problem);
- •  Some fields are interpolated to 221 using nearest-neighbor algorithm (labeled with asterisk in column three in the list)

## Archiving

- Two or more archiving centers/ two have some of the data:
- National Climatic Data Center (NCDC), merged files for all 25 years available;
- National Center for Atmospheric Research (NCAR), merged files being downloaded;
- San Diego Supercomputing Center (SDSC): contacts in progress;
- Perhaps also University of Maryland

## R-CDAS

- Running in near real-time (similar to the current CDAS that runs with the Global Reanalysis system),
- Precipitation:
- CMORPH, a 1/2-hr high-resolution satellite-based dataset, replaces CMAP over oceans, used for 2003 and beyond;
- No Canadian precipitation; using EDAS precipitation instead
- Mexico and US (N-LDAS) precipitation in real-time;
- Data available after ~ 21 hr delay
- System, including data ingest script, created and tested
- Currently running ~ 4 days behind real time, responsibility of NCEP/CPC

## Some NARR Studies

- Assessment of water and energy budgets in NARR (Luo, Berbery, et al)
- A study of the differences between observed forcing fields and NARR forcing fields (Korolevich et al.)
- Impact of NARR data on climate model simulation (Vasic and Xue)
- Anomalous height and pressure fluctuations (West and Steenburgh)
- Study of mechanisms of warm season precipitation variability (Gochis)