Satellite‐derived indices of stream discharge in Taylor Valley, Antarctica

Abstract

AbstractTemperature indices from NOAA–AVHRR data were developed to predict diurnal and seasonal streamflow in Taylor Valley, Antarctica. Masks of the primary land‐cover types (snow, glacier ice, lake ice, and soils) were created from Landsat TM data using binary threshold methods. The masks were then scaled to AVHRR resolution using modal selection of pixels and applied to both diurnal and seasonal time series of AVHRR temperature data from the 1994–95 austral summer season. A temperature area index (TAI) was calculated for different land‐cover types, as well as for the entire watershed. The TAI was defined as the number of pixels at or above a specified temperature. Diurnal discharge was well characterized by a linear relationship of streamflow to the TAI using a temperature threshold of 259 K from all land class pixels for lower Taylor Valley. Neither index successfully predicted seasonal discharge, most likely due to the mismatch of time scales between the satellite and streamflow data. The TAI has great potential for predicting diurnal streamflow in both Taylor Valley and other remote areas within the McMurdo Dry Valleys of Antarctica. Copyright © 2002 John Wiley & Sons, Ltd.