NCEP-NCAR (R1): An Overview

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NCEP-NCAR (R1): An Overview
Main content

NCEP-NCAR (R1) is the original reanalysis effort. It uses a frozen global state-of-the-art global data assimilation system (as of 11 January 1995). The original database was enhanced (additional, quality checked datasets) by NCAR's Data Support Section. Originally planned to span 1957-96 ("40-Year Reanalysis Project"), it was extended back to 1948 and continues to this day.

Key Strengths

Key Strengths

Global Data Set

Longest running reanalysis that uses rawindsonde data

Used in many publications so it can be used as a baseline reference for many computations

Key Limitations

Key Limitations

Antiquated (1994) data assimilation/model

Low spatial and temporal moisture variability over oceans (mainly model 'first guess' fields)

relatively poor Southern Hemisphere

Please cite data sources, following the data providers' instructions
Suggested Data Citation
Dataset DOIs
Hosted Climate Index Files
Usage Restrictions

varies by download site

Key Figures

Climate Data Guide Image: Taylor Diagram NCEP NCAR Reanalysis

Taylor Diagram NCEP NCAR Reanalysis

Other Information

Years of record
Data time period extended
Yes, data set is extended
Sub-daily, Daily, Monthly
Input Data

Rawindsondes; ICOADS, station data, aircraft, satellite retrievals

Vertical Levels:
Missing Data Flag
Spatially complete
Ocean or Land
Ocean & Land
Spatial Resolution

2.5°x2.5°; 3 hPA top

Model Resolution (reanalysis)

T62 - 28 levels

Data Assimilation Method
Model Vintage (reanalysis)


Key Publications
  1. Kalnay et al.,1996: The NCEP/NCAR 40-Year Reanalysis Project. Bull. Amer. Meteor. Soc., 77, 437–471.
  2. Kistler, R., et al, 2001: The NCEP-NCAR 50-Year Reanalysis: Monthly Means CD-ROM and Documentation. Bull. Amer. Meteor. Soc., 82, 247-267