Evidence for an Oscillatory Rain Rate in a Midwestern Winter Rain

View More View Less
  • a NOAA/ERL/Wave Propagation Laboratory, Boulder, Colorado
  • | b Cooperative Institute for Research in the Environmental Sciences (CIRES), University of Colorado/N0AA, Boulder, Colorado
© Get Permissions
Full access

Abstract

Rain rate during light precipitation in winter was measured with high temporal resolution optical systems at a site in Illinois. In addition to quasi-periodic variations, a clearly sinusoidal oscillation in rain rate was found imbedded in the general precipitation. The phase shift in the occurrence of the oscillation at two sensors, with the simultaneous recording of sinusoidal fluctuations of the attenuation of a millimeter wave signal, allows simulation of this particular rain pattern by a simple model. The basic mechanism that can produce a rain event with such a sinusoidal pattern is not clearly understood.

Abstract

Rain rate during light precipitation in winter was measured with high temporal resolution optical systems at a site in Illinois. In addition to quasi-periodic variations, a clearly sinusoidal oscillation in rain rate was found imbedded in the general precipitation. The phase shift in the occurrence of the oscillation at two sensors, with the simultaneous recording of sinusoidal fluctuations of the attenuation of a millimeter wave signal, allows simulation of this particular rain pattern by a simple model. The basic mechanism that can produce a rain event with such a sinusoidal pattern is not clearly understood.

Save