Product: EAMF from NCEP/NCAR Reanalyses
AAMF from NCEP reanalysis - 2013 - Version metadata

AAMF from NCEP reanalysis - 2013

2018-04-06

2013

Data are NCEP values of effective atmospheric angular momentum functions as calculated from NCEP/NCAR reanalyses archived on pressure surfaces. The Transfer functions and Principal moments in Eubanks (1993)are employed to derive the atmospheric angular momentum functions.
Data are given four-times daily, and each epoch consists of a header record giving the date and time (year,month, day, hour), and data records.
The line after the header contains 9 values of inverted barometer (IB) pressure (or, mass) terms, Non-IB pressure terms, wind (or, motion) terms of X1, X2 and X3, respectively. The wind terms are computed by integrating winds from the Earth surface to 10 hPa, the top of atmospheric model. Note that the inverted barometer correction involves applying the mean atmospheric surface pressure over the whole world ocean to every point over the world ocean.

To convert AAMF_X and Y to milliarcsecond (mas) and AAMF_Z to millisecond (ms), one needs to apply the following scale factors:
AAMF_X and Y (in mas) = AAMF_X and Y *360*60*60*1000/(2*pi);
AAMF_Z (in ms) = AAMF_Z * 24*60*60*1000;

http://files.aer.com/aerweb/AAM/readme.aamf.ncep.reanalysis

6 hours

2013-01-01 00:00:00

2013-12-31 18:00:00

1460

year, month, day, hour, mass_IB_X, mass_IB_Y, mass_IB_Z, mass_NonIB_X, mass_NonIB_Y, mass_NonIB_Z, motion_X, motion_Y, motion_Z

ASCII

13(e16.7)

Irregular

Geophysical fluids, excitation functions, NCEP/NCAR reanalyses

- Salstein, D.A., and R.D. Rosen, 1997: Global momentum and energy signals from reanalysis systems. Preprints, 7th Conf. on Climate Variations, American Meteorological Society, Boston, MA, 344-348.
- Kalnay, E., et al., 1996: The NCEP/NCAR 40-year reanalysis project. Bull. Amer. Meteor. Soc., 77, 437-471.
- Barnes, R.T.H., R. Hide, A.A. White, and C.A. Wilson, 1983: Atmospheric angular momentum fluctuations, length-of-day changes and polar motion. Proc. R. Soc. London, Ser. A, 387, 31-73.

U. S. National Centers for Environmental Prediction (NCEP)

GGFC Special Bureau for the Atmosphere

pnelson@aer.com

onLine

http://files.aer.com/aerweb/AAM/aamf.ncep.reanalysis.2013