Satellite Observations for Identifying Continental-Scale Climate Change over Australia

Abstract

Australia’s large extent and relatively low population density, as well as its range of climates, means that it is heavily dependent upon satellite observations to identify the extent and magnitude of climate change. This work examines three types of satellite missions that are used to assess different aspects of climate change. The first involves the use of radio occultation measurements based on signals from Global Navigation Satellite Systems (GNSS) spacecraft made by low-Earth orbiting (LEO) satellites to identify changes in the height of the tropopause, a sensitive indicator of climate change owing to its response to temperature changes in the troposphere and lower stratosphere. The second deals with rainfall over Australia, as measured by the Tropical Rainfall Monitoring Mission (TRMM), in conjunction with other satellite- and ground-based observations. Such observations are invaluable, given the scarcity of ground-based observations over vast areas of Australia.While a comparison between the TRMM product and existing ground-based data is very good, there appears to be a decrease in the correlation between datasets, the reason for which is still being investigated. Finally, we examine the state of terrestrial water storage over Australia as determined from variations in the regional gravity field as measured by the Gravity Recovery and Climate Experiment (GRACE) twin-satellite mission. The loss of substantial volumes of ground water from the Murray-Darling River Basin in the southeast corner of the continent is very apparent, as is an increase over the northern parts of the country. Together, such satellite missions provide a continental-scale picture of climate change over Australia, with temperature and rainfall variations, as well as water resources, able to be monitored, providing valuable information to natural resource managers and climate modellers who endeavour to predict future changes.