New Zealand Journal of Geology and Geophysics abstracts

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Estimation of the spatial variation of rainfall in the Southern Alps of New Zealand using single-channel infrared satellite images

S. G. BRADLEY
C. D. STOW
M. R. LAURENSON

Department of Physics
University of Auckland
Private Bag 92019
Auckland, New Zealand

Abstract  The efficacy of low-resolution infrared (IR) satellite data for the estimation of the spatial variation of rainfall is examined. Three analysis techniques were applied to 41 NOAA satellite images of the Southern Alps of New Zealand. Estimated rainfall is compared with surface measurements from 35 sites. Single-channel histograms of cloud-top temperature are shown to have limited application but demonstrate the diurnal variation of cloud cover. Plots of the fraction of cloud amount below four selected temperatures in each of 14 areas across the Alps showed strong orographic dependence for low and middle cloud. Three simple regression models of rainfall dependence on cloudiness and position along a transect crossing the Main Divide show stronger correlation with location than with cloudiness. Spatial-coherence plots identify dominant clusters of exposed surface or low cloud and indicate the variability of cover at other altitudes.

Keywords  rainfall; infrared; satellites; orography

New Zealand Journal of Geology and Geophysics, 1995, Vol. 38: 159-169

0028-8306/95/3802-0159 $2.50/0 (c) The Royal Society of New Zealand 1995

PDF file of entire paper: medium quality (1420K); (scanned from paper original: notes about this process)

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