We concentrate on the outgoing IR as simulated by a GCM and observed by a satellite during the Northern Hemisphere winter. A spherical harmonic analysis of the time series of 12 hour infrared radiation (IR) is used to isolate the effects of short (spherical harmonic degrees 16–24), medium (8–15), and long (0–7) waves. In both the satellite and GCM values, the fraction of variance contained in the short (16–24) waves peaks in the midlatitude baroclinic zones; for the long (0–7) waves, the fraction of variance peaks in the tropics and subtropics. the temporal wave persistence is found to increase with size. The GCM has relatively less variance in the long waves, when compared with the satellite. The cross correlation of infrared radiation with the poleward component of the wind is concentrated in the midlatitudes and is of largest magnitude for medium, rather than long, waves. The correlation patterns sharpen with the application of a band-pass filter that isolates the effects of waves with periods of 2.5 to 6.0 days.
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- Synoptic Scale Statistics of the Emitted and Reflected Radiation as Observed by Satellites and Computed by General Circulation Models
T. P. Charlock
K. M. Cattany-Carnes
G. L. Potter
- American Meteorological Society