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MMM/GTP/IMAGe NCAR

SEMINAR

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Spatial Spectral Structures of Rainfall Patterns Based on NEXRAD

Observations

Hsiao-ming Hsu

NCAR/UCAR

Boulder, CO USA

Warm-season rainfall over North America exhibits distinct temporal periodicity and power-law scaling based on an analysis of multi-year rainfall time series. Temporal and spatial rainfall patterns, derived from NEXRAD observations, are investigated in detail using a spectral decomposition method.  Multiscale features are revealed in the averaged one-dimensional spatial spectra. Two separate power-law exponents appear, -4/3 for small scales and -2/3 for large scales with the spectral break at 20 km.  Moreover, the rainfall fields reconstructed from the small-scale spectral coefficients exhibit a cusp shape in their rainrate density distributions suggesting the fields are highly intermittent. The non-zero density distribution interestingly shows a power-law scaling of about -2. In addition, complex spectral structures derived from NEXRAD observations of hurricane rainfall patterns will be discussed.

Thursday, 9 February 2006, 3:30 PM

Refreshments 3:15 PM

NCAR-Foothills Laboratory

3450 Mitchell Lane

Bldg 2 Auditorium (Rm1022)