# Presentation: 015740

## NCEP Regional ReanalysisNARRGlenn K. RutledgeNOMADS PI NESDIS Data Archive Board Briefing 17 March 2004 

## Briefing Overview

- NARR Informational Briefing
- NARR Overview
- Improvements over Global Reanalysis
- Domain / Resolution / Frequency
- NCDC NARR:  Ingest/Archive/Access

## North American Regional Reanalysis (NARR): Background

- The NARR is an improved long term re-analysis of basic meteorological fields on a high resolution gird, that for the first time on any scale, includes precipitation.
- NCDC has agreed to archive most of these new data.
-  This is an informational briefing for the DAB for
- NARR availability with background information
- Provide access information

## NARR:  Purpose 

- Create a long-term set of consistent climate data on a regional scale on a North American domain
- Superior to NCEP/NCAR Global Reanalysis (GR) due to:
- use of a regional model (the Eta model)
- Advances in modeling and data assimilation since 1995,  especially:
- Precipitation assimilation
- Direct assimilation of radiances
- Land-surface model updates

## ETA / NOAH LAND-SURFACE MODEL UPGRADES:

_**ETA / NOAH LAND-SURFACE MODEL UPGRADES**_**:**

**- 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.
**- Surface Characterization****  **-- maximum snow albedo database
-     (*Robinson & Kukla 1985*)  -- dynamic thermal roughness length
-     refinements
**- Vegetation**
-   -- deeper rooting depth in forests
-   -- canopy resistance refinements

## 180 km                            80 km                                32 km

## Domain Coverage of NARR

## NARR:  Data for Global 

| Dataset | Details | Source |
| --- | --- | --- |
| Radiosondes | Temperature, winds, moisture | NCEP/NCAR Global Reanalysis (GR) |
| Dropsondes | Same as above | GR |
| Pibals | Wind | GR |
| Aircraft | Temp. and wind | GR |
| Surface | Pressure | GR |
| Cloud drift winds | Geostationary satellite | GR |

## NARR: Data for Regional

| Dataset | Details | Source |
| --- | --- | --- |
| Precipitation | CONUS (with PRISM), Mexico, Canada, CMAP over oceans | NCEP/CPC |
| TOVS-1B radiances | Winds, precipitable water over oceans | NESDIS |
| Surface land | Wind, moisture | GR, TDL |
| COADS | Ship and buoy data | NCEP/EMC |
| Air Force Snow | Snow depth | COLA and NCEP/EMC |
| SST | 1-degree Reynolds, with Great Lakes SSTs | NCEP/EMC, GLERL |
| Sea and lake ice | Contains data on Canadian lakes, Great Lakes | NCEP/EMC, GLERL, Canadian Ice Center |
| Tropical cyclones | Locations used for blocking of CMAP Precipitation | Lawrence Livermore National Laboratory |

## NARR Results: Upper-Air

- Compared both GR and RR against fits to raobs
- Root-mean-square (RMS) analysis fits significantly better for temperatures and vector wind speeds
- Wind speed improvement greatest in the upper troposphere, especially in winter
- First guess (3-hr forecast, pre-3DVAR) temperatures not always as favorable for RR compared to GR
- Relative humidity improved for RR for both analysis and first guess

## NARR Results: Near Surface

- First guess, 1997: for temperatures, comparison against ship/buoy only.  Surface temperature RMS improved both in winter and in summer
- 1998: Surface temperatures RMS favorable for NARR in both winter and summer.  RR biases closer to zero and little diurnal variation problem in summer
- 10-m winds: RMS in NARR neither better nor worse compared to GR (remarkably similar!)
- Slow wind biases improved in NARR: just a little in winter, visibly in summer

## NARR 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

## NARR Results: Precipitation (cont)

- Precipitation observations used to prescribe the latent heat profile in Eta
- Model uses given latent heat profile to simulate precipitation
- Resulting precipitation pattern looks very much like the observed precipitation pattern in both summer and winter

## January 1997 Precipitation Results

## January 1997 Precipitation Results

## July 1997 Precipitation Results

## July 1997 Precipitation Results

## NARR: Analysis System

- Precipitation assimilation in EDAS
- Revised 3DVAR to run using the satellite bias corrections for all the satellites
- Updated the RR’s land-surface model
- Ported the RR pilot system from the SGI Origin 3000 to the IBM-SP

## NARR:  System Design

- Fully cycled 3-hr EDAS
- Lateral boundary conditions supplied by GR2
- Forecasts to 72 hr every 2.5 days, using GR2 forecast boundary conditions
- Resolution: 32-km, 45 layers
- NARR time period: 1979-2003 Updated monthly

## NARR: Data Acquisition and Processing

- Acquired precipitation dataset with use of PRISM (Mountain Mapper); disaggregated data to hourly
- Acquired TOVS-1B data for 1979-1997 time period
- Acquired Air Force snowdepth dataset
- Created a high-resolution sea-ice field

## NARR: Archiving Overview

- Several archiving centers
- National Climatic Data Center (10TB)
- National Centers for Atmospheric Research *
- San Diego Supercomputing Center **
- Perhaps University of Maryland

- *   7TB
- ** Ambitious amounts

## NARR: Archive Data Volumes

-    4.1 Gb daily (16 files per day; 8 analysis and 8 first-guess files, every 3 hr)    130 Gb monthly    1.5 Tb yearly    37 Tb entire RR period (25 years)

- NARR: Archive Data Volumes

- Archive a) and b) only: 7.8TB
- + 2.2TB of restart= 10TB

## NCDC: Data Ingest and Archive

- 10TB on HDSS and 7.8TB on NOMADS
- No off-site backup
- Metadata: FGDC, COARDS, and XML
- Dynamic XML and GrADs via NOMADS Infrastructure
- Serviced thru NOMADS – NOMADS is “NARR Ready”
- Traditional ftp or Web browse/plot via NOMADS Web
- NOMADS Distributed Access Services