Includes full-text resources emanating from a complete set of Australian Rangelands Society Proceedings, journal articles from The Rangelands Journal (published by CSIRO Publishing for the Australian Rangelands Society), videos and other resources abou the extensive rangelands of Australia.
A new empirical model of sub-daily rainfall intensity and its application in a rangeland biophysical model
Sub-daily rainfall intensity has a significant impact on runoff and erosion rates in northern Australian rangelands. However, it has been difficult to include sub-daily rainfall intensity in rangeland biophysical models using historical climate data due to the limited number of pluviograph stations with long-term records. In this paper a new empirical model (Temperature I15' model) was developed to predict the daily maximum 15-min rainfall intensity (I15) using daily minimum and maximum temperature and daily rainfall totals from 12 selected pluviograph stations across Australia. The Temperature I15' model accounted for 46% (P less than 0.01) of the variation in observed daily I15 for an independent validation dataset derived from 67 Australia-wide pluviograph stations and represented both geographical and seasonal variability in I15. The model also accounted for 70% (P less than 0.01) of the variation in the observed historical trend in I15 for the full record period (average record period was 37 years) of 73 Australia-wide pluviograph stations. The Temperature I15' model was found to be an improvement on a past empirical model of I15 and can be easily implemented in biophysical models by using readily available daily climate data. However, as the Temperature I15' model only represented 46% of the variation in daily observed I15, the model is best used in simulation studies on timeframes' in excess of 5 years. The new Temperature I15' model was implemented in the runoff equation of the Australia-wide spatial pasture growth model AussieGRASS, which predicts daily water balance and pasture growth for 185 different pasture communities. This resulted in an improved simulation of green cover for 71% of pasture communities but was worse for 25% of communities, with no change for 4% of communities.
Name of Journal:
The Rangeland Journal