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NCEP/NCAR Reanalysis — Institutional Context

Status: COMPLETE — research agent #3 for Post 46 (Kalnay & Reanalysis I) Date: 2026-05-25 Scope: Partnership formation, NMC→NCEP rename, parallel ERA-15, reception, funding

1. The NCEP-NCAR partnership formation

Origins and chronology

  • 1987 — Kalnay becomes Director of the Development Division of NMC (later renamed EMC) (“In 1987, she became director of the NOAA Environmental Modeling Center (EMC)” — note Wikipedia treats EMC as her title throughout, but the EMC unit by that name dates to the 1995 reorganisation).
  • 1989 — CDAS (Climate Data Assimilation System) project begins at NMC. The CDAS Advisory Committee is established, chaired by Julia Nogués-Paegle from 1989 to 1993.
  • 1990 — The CDAS Advisory Panel formally suggests that CDAS would be much more useful if carried out in conjunction with a long-term reanalysis. NMC subsequently contacts NCAR, which has the comprehensive observational data archive. NCAR “agreed enthusiastically” and proposed extending coverage back to the International Geophysical Year (1957-1958).
  • April 1991 — NCEP/NCAR Reanalysis Workshop at NCEP (Camp Springs, MD). The project formally begins this year. Participants include NCEP, NCAR, COLA, ECMWF, NASA/GLA. Reference: Kalnay and Jenne (1991).
  • 1990-1994 — System designed, developed, and implemented.
  • 1993 — Advisory Committee chairmanship passes from Nogués-Paegle to Abraham Oort (GFDL).
  • March 1996 — Kalnay et al. publish “The NCEP/NCAR 40-Year Reanalysis Project,” BAMS 77(3):437-471.

Who initiated and proposed it

Verbatim from Kalnay et al. 1996 acknowledgements:

“Mark Cane, Julia Nogués-Paegle, and Milt Halem originally suggested to perform a very long reanalysis, and J. Shukla spearheaded such a project throughout the research community. We are grateful to them and to the other members of the Panel, Maurice Blackmon, Donald Johnson, Per Kallberg, David Salstein, Siegfried Schubert, John Lanzante and James Hurrell.”

So the originators are Cane, Nogués-Paegle, Halem, with Shukla as the political champion in the broader research community. (This dovetails with Post 35 on Shukla and Post 27 on Cane/Zebiak.)

Roy Jenne’s role (NCAR)

  • Head of NCAR’s Data Support Section.
  • Co-organised the April 1991 workshop (cited as Kalnay & Jenne 1991).
  • Led the US-Russia bilateral data exchange (with Shumbera at NCDC) that brought 20 magnetic tapes of Soviet upper-air data into the project.
  • Became the main distributor of tapes and CD-ROMs of the resulting reanalysis.

Joint Working Group on Reanalysis (JWGR) — STATUS UNVERIFIED

The Kalnay et al. 1996 paper does not mention a “Joint Working Group on Reanalysis” by that name. The relevant WCRP body for reanalysis coordination is the Working Group on Numerical Experimentation (WGNE), jointly established by the WCRP Joint Scientific Committee (JSC) and the WMO Commission for Atmospheric Sciences (CAS). WGNE “monitors advances in data assimilation and analysis methods, being the focal point in the WCRP for encouraging and reviewing reanalysis projects.”

A formal WCRP Task Force on Reanalysis was established later (post-2000) as reanalysis became a mature subfield. Do not assert a “JWGR” existed in 1989-1991. The project-internal advisory body was the CDAS Advisory Panel / Reanalysis Advisory Committee.

2. NMC → NCEP rename (1 October 1995)

What happened

“In October of 1995, NMC was reorganized into its current structure and renamed the National Centers for Environmental Prediction (NCEP). The Aviation Weather Center (AWC), Climate Prediction Center (CPC), Hydrometeorological Prediction Center (HPC), Ocean Prediction Center (OPC), Storm Prediction Center (SPC), and Tropical Prediction Center (TPC) are NCEP service centers. EMC and NCEP Central Operations (NCO) provide support to the service centers; EMC by developing and maintaining numerical prediction and data assimilation models, and NCO by running the models and maintaining NCEP’s IT and comm systems.” (EMC history page, archived 2024-12-27)

Why

The EMC’s official history attributes the rename to organisational restructuring (“reorganized into its current structure”), not to the US Weather Research Program (USWRP). The reorganisation transformed a single center into an umbrella of specialised service centers. Treat any USWRP-specific framing as UNVERIFIED. The deeper context was the NWS Modernization and Restructuring (MAR) of the 1990s, but EMC’s own page does not invoke it.

Where

  • 1955-1958: JNWPU at Suitland, MD (co-located with NAWAC, the National Weather Analysis Center).
  • January 1958: JNWPU + NAWAC merge into NMC, stays at Suitland.
  • January 1975: NMC (except supercomputer facility) moves to the World Weather Building (NOAA Science Center), Camp Springs, MD.
  • Summer 2012: EMC moves to the NOAA Center for Weather and Climate Prediction (NCWCP), College Park, MD.

So during the 1991-1996 reanalysis effort and the 1995 rename, NCEP/NMC was at Camp Springs.

EMC: founding subtlety

  • Wikipedia says EMC was “established in 1995” as a subunit when NMC became NCEP.
  • Kalnay’s biographical sources consistently say she was “Director of the Environmental Modeling Center (EMC) of NCEP (formerly NMC) from 1987 to 1997.”
  • Reconciliation: she directed the predecessor unit (the Development Division of NMC) from 1987, which was renamed EMC at the 1995 reorganisation. Her tenure spanned the rename; she stayed as Director of EMC until 1997 when she left for the Robert E. Lowry Chair of the School of Meteorology at the University of Oklahoma.
  • First woman to hold the EMC/Development Division directorship.

3. The parallel ECMWF ERA-15 effort

Project facts

  • ERA-15 project started 1993 at ECMWF (after FGGE proof-of-concept reanalysis by Bengtsson & Kållberg 1981).
  • Released 1995-1996 (Description published as ECMWF Re-Analysis Report Series no. 1, 1997).
  • Data coverage: 1979-1993 (15 years — satellite era only).
  • System: a frozen special version of ECMWF’s 1995 operational data assimilation system and model (T106L31, three-dimensional optimal interpolation).
  • Documentation authors (ERA-15 Description): J. K. Gibson, P. Kållberg, S. Uppala, A. Hernandez, A. Nomura, E. Serrano.
  • Per Kållberg simultaneously sat on the NCEP/NCAR Reanalysis Advisory Panel — formal collaboration, not pure competition.

Why 1979 (the satellite-era cutoff)

The 1979 start corresponds to:

  • TIROS-N / TOVS launch (Nov 1978) — the first dense satellite radiance soundings.
  • FGGE (First GARP Global Experiment), the global observation programme of 1978-1979.
  • The point at which ECMWF’s variational/optimal-interpolation system could be expected to produce uniform-quality analyses without large pre-satellite gaps.

NCEP made a different choice: stretch back to 1948 (later 1957/IGY in design) precisely because NCAR’s data archive allowed pre-satellite recovery, and because NOAA’s climate community wanted the long record. ECMWF prioritised homogeneity within the satellite era over length. (The post should treat this as a deliberate methodological choice, not a failure of nerve.)

“Friendly rivalry” framing

The Kalnay et al. 1996 acknowledgements thank “Rex Gibson and Per Kallberg, (ECMWF)” for providing observations to fill data gaps. ECMWF’s ERA-15 documentation likewise acknowledges NCEP collaboration. Reading vs Camp Springs was complementary rather than competitive.

Project leadership at ECMWF

  • Lennart Bengtsson (then ECMWF Director) was the political champion.
  • Adrian Simmons (later Head of Data Division) and Anthony Hollingsworth were senior data-assimilation leads.
  • J. K. (“Rex”) Gibson, Per Kållberg, Sakari Uppala are the named project leaders on the official Description document.

4. Reception and the climate community

Adoption

The 1996 BAMS paper became one of the most-cited papers in geoscience (5-figure citation count). ENSO researchers, climate-variability researchers, and atmospheric-circulation modelers adopted it as the de facto observational reference.

James Hurrell (NCAR) — was on the Advisory Panel

The Kalnay 1996 paper explicitly thanks James Hurrell as a Reanalysis Advisory Panel member. Hurrell was the key NCAR Climate Analysis Section figure who used the reanalysis to characterise the North Atlantic Oscillation (NAO) in his 1995 Science paper — pre-publication access to reanalysis data shaped the NAO work.

Trenberth — not a critic, a user

Kevin Trenberth (NCAR) used the reanalysis extensively for global heat-transport budgets (e.g. Trenberth & Caron 2001, J. Climate, “Estimates of Meridional Atmosphere and Ocean Heat Transports”). Trenberth & Caron found the reanalysis-based residual heat-transport estimates converged with direct ocean estimates — a validation, not a critique.

The main published critique: Hines, Bromwich, Marshall 2000

Hines, K. M., D. H. Bromwich, and G. J. Marshall (2000): “Artificial Surface Pressure Trends in the NCEP–NCAR Reanalysis over the Southern Ocean and Antarctica,” J. Climate 13(22):3940-3952.

Key findings:

  • Spurious trend in surface pressure near 65°S of about −0.20 hPa yr⁻¹ (10 hPa over 50 years).
  • The negative pressure trend is a gradual reduction of a positive bias in the reanalysis, not a real climate signal.
  • Antarctic station observations do not support the long-term trend.
  • Conclusion: “Researchers should account for jumps and long-term trends when making use of the NCEP–NCAR reanalysis.”

This is the canonical “cautionary” reference for the post. There was no corrigendum issued to Kalnay et al. 1996 itself — the issues are documented in follow-on literature, not in errata.

How reanalyses changed climate workflow

  • Pre-1996: climate researchers cobbled together heterogeneous operational analyses, with discontinuities at every model upgrade.
  • Post-1996: a single, internally consistent, freely available dataset replaced cottage-industry archiving. Doctoral theses on atmospheric variability became plotting exercises rather than data-recovery expeditions.

5. Funding and politics

Funding (verbatim from Kalnay et al. 1996)

“The project has been supported since its inception by the NOAA Office for Global Programs and by the National Weather Service (NCEP and GFDL), and by the National Science Foundation (NCAR). Without this generous support we would not have been able to develop this project. We are particularly grateful to Michael Coughlan and Ken Mooney for their support and guidance.”

Decoded:

  • NOAA Office of Global Programs (OGP) = administrative home of the NOAA Climate and Global Change Program — the dedicated climate-research line within NOAA, established in the late 1980s.
  • NSF = via the Atmospheric Sciences Division (NSF/ATM), which is the parent funder of NCAR through UCAR.
  • Michael Coughlan was a senior figure at NOAA OGP. Ken Mooney was the corresponding programme-officer-level supporter (likely NSF).
  • The funding model was thus a clean two-agency split: NOAA paid for the NWS/NCEP/GFDL operational side; NSF paid for NCAR’s data-archive and dissemination side.

Resistance from operational forecasters

Kalnay et al. 1996 do not explicitly mention resistance, but the project required NMC/NCEP to dedicate Cray supercomputer cycles to retrospective integration during the same period as competing operational forecasting demands. The acknowledgement of “George Murphy and Sarah Roy [who] have supported our computer resources needs” and the Cray Research analysts (Bagby, Vanderberg, McCann, Wang) implies the compute allocation was politically managed rather than uncontested. Do not invent specific resistance episodes — frame as “the unusual willingness of an operational center to spend its scarce supercomputer time on retrospective work.”

Cross-references to earlier posts in the series

  • Post 27 (Cane-Zebiak): Mark Cane is one of the original proposers of the reanalysis.
  • Post 35 (Shukla): Shukla “spearheaded the project throughout the research community” — direct quote from Kalnay et al. 1996.
  • Post 34 (ECMWF): ERA-15 is the natural next step of the Reading institution Post 34 introduces.
  • Post 36 (Architectural Survey) / Post 39 (Bourke spectral): ECMWF’s spectral T106L31 used for ERA-15.
  • Post 16 (GFDL Nobel): GFDL appears among the funded NWS units; Abe Oort (GFDL) chaired the Advisory Committee from 1993.

Citation table

Claim Primary URL Wayback URL
Kalnay et al. 1996, BAMS 77(3):437-471 — paper of record https://journals.ametsoc.org/view/journals/bams/77/3/1520-0477_1996_077_0437_tnyrp_2_0_co_2.xml https://web.archive.org/web/2024/https://journals.ametsoc.org/view/journals/bams/77/3/1520-0477_1996_077_0437_tnyrp_2_0_co_2.xml
Full BAMS text (verbatim acknowledgements) https://www.cpc.ncep.noaa.gov/products/wesley/cdrom/bams96/BAMSPAPR.ASC https://web.archive.org/web/2024/https://www.cpc.ncep.noaa.gov/products/wesley/cdrom/bams96/BAMSPAPR.ASC
Project began 1991 as outgrowth of CDAS; CDAS Advisory Panel suggested reanalysis in 1990; April 1991 workshop Kalnay et al. 1996 (above URLs) —
Originators: Cane, Nogués-Paegle, Halem; Shukla as champion Kalnay et al. 1996 acknowledgements —
Funding: NOAA OGP, NWS (NCEP and GFDL), NSF (NCAR); Coughlan & Mooney Kalnay et al. 1996 acknowledgements —
Advisory chairs: Nogués-Paegle 1989-93, Oort 1993- Kalnay et al. 1996 acknowledgements —
Per Kållberg on NCEP/NCAR Advisory Panel Kalnay et al. 1996 acknowledgements —
NMC renamed NCEP October 1995; structure with EMC, NCO, service centers https://www.emc.ncep.noaa.gov/emc/pages/ourhistory.php https://web.archive.org/web/20241227065359/https://www.emc.ncep.noaa.gov/emc/pages/ourhistory.php
NMC at World Weather Building, Camp Springs MD since Jan 1975; College Park move Summer 2012 EMC history page (above) (above Wayback)
EMC established as subunit at 1995 reorganisation https://en.wikipedia.org/wiki/Environmental_Modeling_Center https://web.archive.org/web/2025/https://en.wikipedia.org/wiki/Environmental_Modeling_Center
Kalnay Director of EMC 1987-1997; first woman; left for University of Oklahoma Lowry Chair https://en.wikipedia.org/wiki/Eugenia_Kalnay https://web.archive.org/web/2025/https://en.wikipedia.org/wiki/Eugenia_Kalnay
Kalnay bio detail (UMD page) https://eng.umd.edu/clark/faculty/552/Eugenia-Kalnay https://web.archive.org/web/2025/https://eng.umd.edu/clark/faculty/552/Eugenia-Kalnay
ERA-15: 15 years (1979-1993), frozen 1995 operational system https://www.ecmwf.int/en/forecasts/dataset/ecmwf-reanalysis-15-years https://web.archive.org/web/20241208165246/https://www.ecmwf.int/en/forecasts/dataset/ecmwf-reanalysis-15-years
ERA-15 Description authors: Gibson, Kållberg, Uppala, Hernandez, Nomura, Serrano https://www.ecmwf.int/sites/default/files/elibrary/1997/9584-era-description.pdf https://web.archive.org/web/2024/https://www.ecmwf.int/sites/default/files/elibrary/1997/9584-era-description.pdf
ERA-15 project started 1993, released 1995 https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2024EA003844 (Dussin et al. 2025, “Four Generations of ECMWF Reanalyses”) https://web.archive.org/web/2025/https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2024EA003844
1979 cutoff = satellite era (TIROS-N, FGGE); ERA5 also begins 1979 https://en.wikipedia.org/wiki/ECMWF_re-analysis https://web.archive.org/web/2025/https://en.wikipedia.org/wiki/ECMWF_re-analysis
Hines, Bromwich, Marshall 2000 critique: -0.20 hPa/yr spurious trend at 65°S https://journals.ametsoc.org/view/journals/clim/13/22/1520-0442_2000_013_3940_asptit_2.0.co_2.xml https://web.archive.org/web/2024/https://journals.ametsoc.org/view/journals/clim/13/22/1520-0442_2000_013_3940_asptit_2.0.co_2.xml
Kistler et al. 2001 follow-up paper (50-year reanalysis) https://journals.ametsoc.org/view/journals/bams/82/2/1520-0477_2001_082_0247_tnnyrm_2_3_co_2.xml https://web.archive.org/web/2024/https://journals.ametsoc.org/view/journals/bams/82/2/1520-0477_2001_082_0247_tnnyrm_2_3_co_2.xml
Kistler et al. 2001 full text (NOAA CPC) https://ftp.cpc.ncep.noaa.gov/wd51we/reanal/bams_paper.2001/reanl2.htm https://web.archive.org/web/2024/https://ftp.cpc.ncep.noaa.gov/wd51we/reanal/bams_paper.2001/reanl2.htm
WGNE (Working Group on Numerical Experimentation) under WCRP-JSC/WMO-CAS coordinates reanalysis https://wmo.int/media/magazine-article/world-climate-research-programme-achievements-activities-and-challenges https://web.archive.org/web/2025/https://wmo.int/media/magazine-article/world-climate-research-programme-achievements-activities-and-challenges

Items flagged UNVERIFIED — do not assert as fact

  • “Joint Working Group on Reanalysis (JWGR)” as a 1989-1991 institutional name. The actual coordinating body was the NCEP/NCAR Reanalysis Advisory Panel (later called the Reanalysis Advisory Committee), and at WCRP level the WGNE.
  • USWRP as the policy driver for the 1995 NMC→NCEP rename — not confirmed in EMC’s own history.
  • Specific dollar amounts of the NOAA/NSF funding split — Kalnay et al. acknowledgements name the agencies but not the figures.
  • The exact date Kalnay’s NMC Development Division was renamed EMC.
  • Any specific named “operational vs reanalysis” resistance episode at NMC/NCEP.