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Radio Occultation Observations As Anchor Observations In Numerical Weather Prediction Models and Associated Reduction of Bias Corrections In Microwave and Infrared Satellite Observations


Satellite radiance measurements are used daily at numerical weather prediction (NWP) centers around the world, providing a significant positive impact on weather forecast skill. Owing to the existence of systematic errors, either in the observations, instruments, and/or forward models, which can be larger than the signal, the use of infrared or microwave radiances in data assimilation systems requires significant bias corrections. As most bias-correction schemes do not correct for biases that exist in the model forecasts, the model needs to be grounded by an unbiased observing system. These reference measurements, also known as “anchor observations,” prevent a drift of the model to its own climatology and associated biases, thus avoiding a spurious drift of the observation bias corrections. This paper shows that the assimilation of global positioning system (GPS) radio occultation (RO) observations over a 3-month period in an operational NWP system results in smaller, more accurate bias corrections in infrared and microwave observations, resulting in an overall more effective use of satellite radiances and a larger number of radiance observations that pass quality control. A full version of the NCEP data assimilation system is used to evaluate the results on the bias corrections for the High Resolution Infrared Radiation Sounder-3 (HIRS-3) on NOAA-17 and the Advanced Microwave Sounding Unit-A (AMSU-A) on NOAA-15 in an operational environment.

Article / Publication Data
Print 0739-0572/Online 1520-0426
Available Metadata
Accepted On
September 30, 2013
Fiscal Year
Publication Name
J. Atmos. Oceanic Technol.
Published On
January 01, 2014
Final Online Publication On
January 01, 2014
Publisher Name
Amer Meteorological Soc
Print Volume
Print Number
Page Range
Submitted On
March 04, 2013


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Authors who have authored or contributed to this publication.

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