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Geoffrey J. DiMego
,
Kenneth E. Mitchell
,
Ralph A. Petersen
,
James E. Hoke
,
Joseph P. Gerrity
,
James J. Tuccillo
,
Richard L. Wobus
, and
Hann-Ming H. Juang

Abstract

The recent implementation of changes to the National Meteorological Center's (NMC's) Regional Analysis and Forecast System (RAFS) is described. The changes include an expansion of the innermost grids of the nested-grid model (NGM) and the implementation of the Regional Data Assimilation System (RDAS). The new version of the forecast model and a 3-hourly RDAS analysis system were implemented on 7 August 1991. Some results from tests of the revised forecast model and the combined RDAS/NGM system are presented.

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Ralph A. Petersen
,
Geoffrey J. DiMego
,
James E. Hoke
,
Kenneth E. Mitchell
,
Joseph P. Gerrity
,
Richard L. Wobus
,
Hann-Ming H. Juang
, and
Michael J. Pecnick

Abstract

The final set of changes to NMC's Regional Analysis and Forecast System (RAFS) is described. The changes include modifications to both the forecast model and the analysis model, as well as development of a Regional Data Assimilation System (RDAS). The forecast model changes were developed to correct a number of known deficiencies in the Nested Grid Model (NGM), while the RDAS development will allow the RAFS to take advantage of the new asynoptic data sets soon to be available. Several of the changes were implemented on 7 November 1990. The remaining changes (including the RDAS) are planned for implementation before mid 1991. Results from tests of the revised forecast model and the combined RDAS/NGM system are presented and discussed.

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Suranjana Saha
,
Shrinivas Moorthi
,
Hua-Lu Pan
,
Xingren Wu
,
Jiande Wang
,
Sudhir Nadiga
,
Patrick Tripp
,
Robert Kistler
,
John Woollen
,
David Behringer
,
Haixia Liu
,
Diane Stokes
,
Robert Grumbine
,
George Gayno
,
Jun Wang
,
Yu-Tai Hou
,
Hui-ya Chuang
,
Hann-Ming H. Juang
,
Joe Sela
,
Mark Iredell
,
Russ Treadon
,
Daryl Kleist
,
Paul Van Delst
,
Dennis Keyser
,
John Derber
,
Michael Ek
,
Jesse Meng
,
Helin Wei
,
Rongqian Yang
,
Stephen Lord
,
Huug van den Dool
,
Arun Kumar
,
Wanqiu Wang
,
Craig Long
,
Muthuvel Chelliah
,
Yan Xue
,
Boyin Huang
,
Jae-Kyung Schemm
,
Wesley Ebisuzaki
,
Roger Lin
,
Pingping Xie
,
Mingyue Chen
,
Shuntai Zhou
,
Wayne Higgins
,
Cheng-Zhi Zou
,
Quanhua Liu
,
Yong Chen
,
Yong Han
,
Lidia Cucurull
,
Richard W. Reynolds
,
Glenn Rutledge
, and
Mitch Goldberg

The NCEP Climate Forecast System Reanalysis (CFSR) was completed for the 31-yr period from 1979 to 2009, in January 2010. The CFSR was designed and executed as a global, high-resolution coupled atmosphere–ocean–land surface–sea ice system to provide the best estimate of the state of these coupled domains over this period. The current CFSR will be extended as an operational, real-time product into the future. New features of the CFSR include 1) coupling of the atmosphere and ocean during the generation of the 6-h guess field, 2) an interactive sea ice model, and 3) assimilation of satellite radiances by the Gridpoint Statistical Interpolation (GSI) scheme over the entire period. The CFSR global atmosphere resolution is ~38 km (T382) with 64 levels extending from the surface to 0.26 hPa. The global ocean's latitudinal spacing is 0.25° at the equator, extending to a global 0.5° beyond the tropics, with 40 levels to a depth of 4737 m. The global land surface model has four soil levels and the global sea ice model has three layers. The CFSR atmospheric model has observed variations in carbon dioxide (CO2) over the 1979–2009 period, together with changes in aerosols and other trace gases and solar variations. Most available in situ and satellite observations were included in the CFSR. Satellite observations were used in radiance form, rather than retrieved values, and were bias corrected with “spin up” runs at full resolution, taking into account variable CO2 concentrations. This procedure enabled the smooth transitions of the climate record resulting from evolutionary changes in the satellite observing system.

CFSR atmospheric, oceanic, and land surface output products are available at an hourly time resolution and a horizontal resolution of 0.5° latitude × 0.5° longitude. The CFSR data will be distributed by the National Climatic Data Center (NCDC) and NCAR. This reanalysis will serve many purposes, including providing the basis for most of the NCEP Climate Prediction Center's operational climate products by defining the mean states of the atmosphere, ocean, land surface, and sea ice over the next 30-yr climate normal (1981–2010); providing initial conditions for historical forecasts that are required to calibrate operational NCEP climate forecasts (from week 2 to 9 months); and providing estimates and diagnoses of the Earth's climate state over the satellite data period for community climate research.

Preliminary analysis of the CFSR output indicates a product that is far superior in most respects to the reanalysis of the mid-1990s. The previous NCEP–NCAR reanalyses have been among the most used NCEP products in history; there is every reason to believe the CFSR will supersede these older products both in scope and quality, because it is higher in time and space resolution, covers the atmosphere, ocean, sea ice, and land, and was executed in a coupled mode with a more modern data assimilation system and forecast model.

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