Equatorial Zonal Circulations from the NCEP-NCAR Reanalysis.

A note on the deficiency of NCEP/NCAR reanalysis surface winds over the equatorial Indian Ocean

[1] The seasonal cycle and intraseasonal variability of the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP) reanalysis surface winds over the Indian Ocean (IO) are assessed by comparing them with in situ surface observations from two moored buoys and winds from the SeaWinds scatterometer on the QuikSCAT satellite. The buoys are located in the centra...

On Equatorial Pacific Surface Wind Changes around 1977: NCEP-NCAR Reanalysis versus COADS Observation

The Hadley circulation: assessing NCEP/NCAR reanalysis and sparse in-situ estimates

We present a comparison of the zonal mean meridional circulations derived from monthly in situ data (i.e. radiosondes and ship reports) and from the NCEP/NCAR reanalysis product. To facilitate the interpretation of the results, a third estimate of the mean meridional circulation is produced by subsampling the reanalysis at the locations where radiosonde and surface ship data are available for t...

Artificial Surface Pressure Trends in the NCEP–NCAR Reanalysis over the Southern Ocean and Antarctica*

An examination of 50 years of the National Centers for Environmental Prediction (NCEP)–National Center for Atmospheric Research (NCAR) reanalysis from 1949 to 1998 reveals that significant spurious trends occur in the surface pressure field. Long-term surface pressure reductions are apparent south of 458S. The largest trend in surface pressure is near 658S where an approximately steady long-ter...

Zonal Circulations

The response of the tropical atmosphere to steady forcing for all four seasons is computed using a simple two-layer linear primitive-equation model allowing an arbitrary basic flow with two-dimensional shear. The character of each seasonal response is studied, and two distinct forms of behavior are found. Near the Equator, the forcing excites a slowly varying Kelvin wave of the time scale of mo...