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Following the statistical analyses of long‐term rainfall‐runoff records from research basins in humid temperate latitudes, Hewlett and co‐workers extended the global challenge to disprove their findings that rainfall intensity was non‐significant. This paper responds to Hewlett's challenge as no preceding analyses have involved forested basins in a tropical cyclone‐prone area. Based on a 7 year rainfall‐runoff record, quickflow (QF), peak flow (QP) and quickflow response ratios (QRR) were regressed as dependent variables against rainfall parameters (intensity, Pi, amount, P), storm duration, D and antecedent flow, I. These data sets were categorised into total streamflow (Q) classes and stratified into three seasons, (monsoon, post‐monsoon and dry) for forested and cleared catchments. Where rainfall variable collinearity met acceptable levels, the addition of Pi to regression models including P, D, I contributed up to 9% and 66% of the respective variations in quickflow and peak flow. For the highest Q storm classes (monsoon), Pi alone accounted for up to 67% and 91% of the variation in QF and QP respectively and was the dominant influence on QP for all seasons. The very high rainfall intensities experienced in the monsoon season is a causal factor why these results differ from those of other research drainage basins. Surprisingly, Pi continued to have a significant influence on QF for dry season classes when less‐intense rainfall occurs. Further the results were similar for both catchments across all seasons. P was the dominant independent variable affecting QF above a threshold Q of 50 mm (monsoon), as rainfall contributes directly to saturation overland flow and return flow under saturated conditions. Further although QRR increased with increasing Q for each season, the regression results for that parameter were poor possibly due to the non‐linearity of the rainfall‐runoff relationship. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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In a tropical rainforest catchment, shallow piezometers respond almost instantaneously to rainfall, but the dominant ground water recharge mechanisms are not well understood. To improve understanding, the downward movement of soil water on a runoff plot was traced using tritiated water injected at 0·20 m below the surface which marks the lower boundary of active subsurface storm flow. The tritium pulse was translated slowly down the profile, apparently dominated by interstitial piston flow on the lines described by Zimmermann's theoretical model. This recharge mechanism accounted for about 35 per cent of rainfall or 50 per cent of throughfall. The pulse's advance may have also been delayed by the upward movement of soil water indicated by the distribution of hydraulic potential under different hydrological conditions. The result was an increase in soil water transit time particularly below 1·0 m. There was also evidence in the tracer profiles for rapid by-pass flow but the volumes concerned could not be quantified in this experiment. 相似文献
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The spontaneous combustion of coal causes widespread underground coal fires in several countries, amongst which is China. These coal fires cause serious environmental, economic and safety problems. In northern China, the coal fires occur within a wide region stretching 5000 km east-west and 750 km north-south. Remote sensing therefore provides an ideal tool for monitoring this environmental hazard over such a large and remote area. As part of a research project to detect, measure, monitor and extinguish these coal fires, this paper describes a remote-sensing-based multi-sensor data-fusion methodology for detecting the underground fires. The methodology is based on fusing a variety of satellite-based image types (optical, thermal, microwave) together with airborne data (optical and thermal infrared) and ancillary data sources such as geological and topographic maps. The results of the remote-sensing data fusion are presented, using pixel-based, feature-based and decision-based fusion approaches. 相似文献
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Natural Hazards - Quang Nam province, central Vietnam, is situated within the tropical monsoon and typhoon zone of south-east Asia and is susceptible to extreme floods. Historical water level data... 相似文献
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Child disadvantage is an important issue in Australia today and is one of the key policy target areas of the Federal government. Child disadvantage not only affects child wellbeing in the present time but can also inhibit their future achievements. As well as individual- and family-level effects, there is growing evidence that child wellbeing and achievement is highly affected by the environment in which children grow up, and what resources and role models are available to them in their surrounding areas. In this paper, we examine the spatial clustering of children in jobless households through the computation of the Global and Local Moran's statistics, for the Sydney and Melbourne metropolitan regions, and observe how these clusters have changed between the 2001 and 2006 census years. We find that there are significant spatial clusters of children in jobless households in both periods, suggesting that ‘place’ is a driver of this particular phenomenon. Further, we observe an expansion of ‘hot spots’, in both Sydney and Melbourne, suggesting that areas with high proportions of children in jobless households have both persisted and increased despite the sizeable economic growth in Australia over the same period. 相似文献
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