# Presentation: 149110

## An Overview of the North American Regional Reanalysis

- W. Ebisuzaki, F. Mesinger, G. DiMego, E. Kalnay, K. Mitchell, M. Ek, R. Grumbine, D. Jovic, P. Shafran, and J. Woolen
-      http://wwwt.emc.ncep.noaa.gov/mmb/rreanl/index.html

## Motivation for North American           Regional Reanalysis  (NARR)                  

- Create hi-resolution reanalysis for the North American domain
- Address some of the weakness of the N/N Reanalysis,   i.e., near surface temperature, winds
- Hydrology in the North American domain
- Make a more useful reanalysis (for people who want  point values and live on the surface
-                                                 Expectations
- more applied meteorological applications
- more uncertain about how non-meteorologists will use the data

## High Lights of NARR

- ETA model and assimilation system (EDAS)
- 32 km resolution over the North and Central America
- R-2 horizontal boundary conditions
- new land surface model (NOAH)
- precipitation assimilation
- 8x daily analyses from October 1978 onwards
- 5 TB for basic set of analyses and fluxes
- Oct 1978-Nov 2002 done

## NARR domain

## 180 km (~ CDAS) vs 32 km (NARR) resolution topography

## ETA / NOAH LAND-SURFACE MODEL UPGRADES: 24 Jul 01

_**ETA / NOAH LAND-SURFACE MODEL UPGRADES**_**: ****24 Jul 01**

**- assimilation of hourly precipitation**
**  **-- hourly 4-km radar/gage analysis (Stage IV)
**- cold season processes**(*Koren et al 1999*)  -- patchy snow cover  -- frozen soil (new state variable)  -- snow density (new state variable)  **- bare soil evaporation refinements**
-   -- parameterize upper sfc crust cap on evap
**- soil heat flux**  -- new soil thermal conductivity
-     (*Peters-Lidard et al 1998*)  -- under snowpack (*Lunardini, 1981*)  -- vegetation reduction of thermal cond.    (*Peters-Lidard et al 1997*)
**- surface characterization****  **-- maximum snow albedo database
-     (*Robinson & Kukla 1985*)  -- dynamic thermal roughness length
-     refinements
**- vegetation**
-   -- deeper rooting depth in forests
-   -- canopy resistance refinements

- NOAH LSM tested in various land-model
- intercomparison projects, e.g., GSWP, PILPS
-  2a, 2c, 2d, 2e, Rhone, and (near-future) DMIP.

## January 1997 Precipitation Results

## Precipitation

- Several sources of precipitation
- CONUS data with PRISM (Mountain Mapper) to improve orographic effects
- Canada
- Mexico
- CMAP (combination of satellite and gauge data) over oceans; CMAP is blocked:
- Near central areas of hurricanes (7.5 by 7.5 deg)
- Observed precipitation > 100 mm/day
- A 15-degree 'blending belt' between 27.5 and 42.5 N, with no CMAP north of 42.5 N

## Comparison of N/N Reanalysis and NARRmodel

- Global
- Spectral
- ~250 km resolution
- 28 sigma levels
- Land sfc (Pan and Marht, 1987)
- One soil type (sandy loam)
- Two soil levels
- Simplistic snow depth, fn(T)
- 6 hour analyses time steps

- N. Am. Sector
- Grid point
- 32 km resolution
- 45 pressure levels
- NOAH model (2002)
- Realistic soil types
- 4 soil layers
- Snow depth, modeled/observed
- 3 hour analyses time steps

## Comparison of N/N Reanalysis and NARRinput observations

- Sondes, aircraft
- TOVS temperature retrievals
- Satellite winds
- Land sfc: prs
- Ocean sfc: prs, q, t, winds
- Snow cover: old is low res
- Reynold's SST
- Sea ice from R. Grumbine

- Sondes, aircraft, profilers
- Direct assimilation of radiances
- Satellite winds
- Land sfc: prs, q, winds
- Ocean sfc: prs, q, t, winds
- Precipitation
- USAF snow depth (hi res)
- Reynold's SST + lakes
- Sea ice from R. Grumbine + lakes

## Comparison of N/N Reanalysis and NARRdates

- Software: ~1994
- Analyses: 1948-present

- Software: ~2002
- Analyses: Oct 1978-Nov 2002
-  Nov 2002+ in development

## Operational ETA vs NARR

- 12 km
- 60 levels
- Evolving physics
- Precip assim for CONSUS
- Lakes: SST, ice-real time

- 32 km
- 45 levels
- Frozen physics
- Better precip obs
- Better lake obs

## Operational ETA vs NARRUser Output: RR is more friendly

- RR: 1 grib table vs 3 grib tables for OPN
-      (some software cannot handle multiple tables)
- RR: Winds are N/S vs grid-relative winds in OPN
-      (some software cannot handle grid-relative winds)
- RR: new variables: moisture fluxes, etc
- RR: redundant variables removed: ex dew pt, rel q, specific q
- RR: added new BL levels, removed others
- RR: BUFR files have QC and increments
- RR: many monitoring plots

## Why NARR should have better surface values

- 1) higher horizontal orography: 32 km vs ~250 km
-       need to resolve orography
-  2) better land surface model
-         to get 2m temp and q .. need better sfc fluxes
-  3) assimilated precipitation
-      better model precipitation .. clouds, radiative flux
-      better soil moisture .. latent and sensible heat flux
-  4) gridded snow depth is similar to NARR resolution
-      a problem with NCEP's global reanalyses
-  5) assimilate more near surface data (winds, q)
-  6) 3 hour assim cycle, better resolve diurnal cycle

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## Principal Output Datasets

- Observations with QC marks, increments (BUFR)
- plots: obs locations, fit to sondes, fit to sfc obs,
- fit to global reanalysis, various NARR fields
- binary restart files (to rerun model, high resolution),  very big, small usage
- GRIB analyses and first guess on model grid  big, no interpolation errors
- GRIB analyses and first guess on Lambert conformal 32-km  grid, big, easier to use,  interpolation error
- Merged:  GRIB analyses and averaged/accumulated flux/precip and some 1st guess fields for water budgets, Lambert Conformal grid (AWIP 221), 5 TB for 8x daily for entire period. This will be work-horse data set.

## Data Distribution

- NCAR
- SDSC (San Diego Super Computing Center, UCSD)
- U. of Maryland
- NCDC-NOMADS  (NOAA Operational Model Archive Distribution System)

## NOMADS

- Partnership of many organizations including core collaborators: CDC, COLA, FSL, GFDL, LLNL, NCAR, NCDC, NCEP, PMEL, UNIDATA
- On-line access to the merged RR data set (analyses + fluxes+some first guess)
- NCDC: 7 TB on-line storage, web servers,  x-TB tape storage
- NCEP: 3⁄4 TB on-line, web servers, software upgrades
- Software:
- on-line plotting package
- on-line slice-and-dice of GRIB files
- GrADS-DODS
- Status:
- plotting package will be enhanced by NCEP
- downloading of GRIB files will be enhanced by NCEP
- GrADS-DODS needs enhancements
- NOMADS-NCDC has experience running software

## I can't download the 5 TB merged data set!

- Download what you want:
- Select:
- 	1) variables
- 	2) levels
- 	3) times
- 	4) domain
- 	5) resolution: 32 km, 64 km, 96 km
- Downloading can be scripted

## Summary

- Oct 4, 2003	 Finished Oct 1978 to mid-Nov 2002
- 		         no more inland lake data
- 		         no 2003 Canadian precip
- currently	planning the real-time NARR
- 		        will use different datasets as some
- 		        precip/lake data are not available in real time
- currently	planning subsets and archive
- Dec 2003	internet-2 will be available at NCDC and
- 		distribution to archive sites can start
- Until NARR appears at archive sites, you can look at
- 1 year of merged data at NCEP.
-      http://wwwt.emc.ncep.noaa.gov/mmb/rreanl/index.html