Emeritus Professor Jetse Kalma

In this paper we present a variable bucket capacity (VBC) representation of TOPMODEL (Beven and Kirkby, 1979), generalizing the Manabe 'simple bucket' scheme widely used in climate models. In doing this, we have been motivated by the variable infiltration capacity (VIC) model presented by Wood et al. (1992). For catchments, or for parts of the land surface, whose hydrology fits the TOPMODEL assumptions, this lumped version offers an alternative representation that can be used as the building block for land surface hydrology models at large spatial scales. The model is first applied, with satisfactory results, to a small catchment near Canberra in Australia. Next, using the same model, the effects of random spatial variability of rainfall are studied, but in the context of land surface hydrological parameterizations for global climate models. Sub-grid rainfall variability, especially the partial coverage that characterizes rainfall events at such large scales, is found to cause significant biases in the estimation of land surface fluxes. Other manifestations of the effects of the spatial variability of rainfall are also investigated, also by means of model simulations, but with a view to gaining insights for developing simple parameterizations of land surface fluxes at large scales. This includes the investigation of the dynamics, i.e. spatial and temporal variability, of the soil moisture state variable during and after a rainfall event. In addition, empirical relationships linking the variable contributing area, subsurface runoff and evaporation, to a soil moisture state variable (e.g. soil moisture storage), are derived based on model simulations, and the effects of the sub-grid rainfall variability on these relationships are examined. Because of the strong non-linearity inherent in the process descriptions within the model, the above 'constitutive' relationships are strongly affected by rainfall heterogeneity. © 1997 by John Wiley & Sons, Ltd.

Over the last 35 years solar radiation in Hong Kong has decreased by more than one-third. During the same period the population doubled and the total use of fossil fuels increased more than sevenfold. A surface energy balance model was used to demonstrate the opposing effects of the decline in irradiance and the increase in anthropogenic heat production on air temperature. Differences between air temperatures measured in the city and at an upwind, unpopulated island were used to verify the simulated decrease in the urban heat-island by day and increase at night, leading to an unchanged mean air temperature difference. The implications of these results for climate change in the rapidly urbanizing Pacific Rim region are discussed briefly. Copyright © 1995 John Wiley & Sons, Ltd

A catchment-wide soil moisture index based on spatially distributed point measurements of soil moisture is used to describe the temporal trend in regional soil moisture status in a 26 km2 catchment in south-eastern Australia. The temporal variation in runoff, evaporation and soil moisture storage is simulated with a modification of the lumped SFB water balance model of Boughton (1984), which assumes a fixed bucket size, and with the variable infiltration capacity (VIC) model of Wood et al. (1992), which assumes a variable bucket representation. Comparison of simulated catchment soil moisture storage and the soil moisture index based on measurements indicates that both models can make useful predictions of soil moisture status at the catchment scale, with the VIC model performing slightly better than the SFB model. It is also shown that the quasi-distributed VIC model can predict the relative wetness at individual locations, given their relative frequency of occurrence, thus allowing the disaggregation of catchment-scale storage values to point-scale soil moisture values. Copyright © 1995 John Wiley & Sons, Ltd

Interannual variation in both annual and maximum and minimum monthly values was small and less than the accuracy of the measurements. Limitations of accuracy, together with the non-homogeneous and non-continuous nature of much of the data and the data processing procedures adopted at some periods, suggest that changes in measurement strategy are needed if secular, i.e. long-term, variations of the magnitude measured over much of the northern hemisphere are to be distinguished within a reasonable period. -from Authors

A regional water-balance study has been carried out from 1986-1993 in a 27 km2 catchment of the Goulburn-Marulan region of New South Wales. Field measurements have been made of water-balance components at a range of spatial and temporal scales. The processing and analysis of data from three climate sites, three additional rainfall-only sites, and two streamflow gauges is described. The construction of a weir for the second streamflow-monitoring site is described and flow over both streamflow-monitoring sites is discussed. The derivation of discharge-rating tables is also presented. A summary table of daily climate and runoff data compiled from all the above-mentioned monitoring sites is given. -from Authors

Over 70 wide ranging papers (abstracted separately) were presented at the symposium and are contributions of the hydrologic atmospheric sciences to the IBGP Core Project BAHC and to the IHP prject H-1-1. The papers are grouped into 13 sections including: terrain evaporation dynamics; water/heat fluxes; soil flux transport; hydrological modelling; land surface process scaling; remote sensing techniques; hydrology and climate; spatial variability of precipitation and evaporation. -R.Gower

TAPES-G, a grid-based method of terrain analysis, SRAD, an approximate method of computing daily global short wave, net long wave and net radiation and extrapolation minimum, maximum and average temperature across a landscape, WET, an approximate method of computing spatially distributed soil water content and evaporation and catchment runoff and EROS, an approximate method for predicting erosion potential, are simple terrain-based models for analysing spatially distributed land surface processes. The spatial variability of the radiation, thermal, soil water, evaporation and erosion regimes on the 27km2 Lockyersleigh catchment in southeastern Australia is explored using these models. -from Authors

Sensible and latent heat flux measurements using Bowen ratio and eddy correlation techniques and aircraft measurements are presented and compared with results obtained with a coupled slab-vegetation model for a 27 km2 grassland catchment in SE Australia. -Authors

A method for spatially disaggregating regional-scale evaporation estimated by a one-dimensional atmospheric boundary layer (ABL) model is presented. An index approach that characterizes the spatial distribution of hydrologic processes in a landscape using terrain attributes, soil and land cover data provides the basis for this disaggregation. The method is tested on the 27 km2 Lockyersleigh catchment in southeastern Australia. -Authors

There is a serious need to reformulate the physics embodied in surface hydrology models to suit the scales of interest. Proposed reformulation strategies are speculative, and intended to stimulate constructive debate. Because of the lack of large-basin-scale hydrology models suited to predicting the consequences of land use change, it is believed that research should strongly emphasise reformulation. On a global scale, because tentative predictions are required urgently, it would be inappropriate to disparage the current emphasis on refining the strategy of scaling up point scale physics with aggregated data. However, at this scale the long-term need for reformulation is greatest, if sound predictions are to be made. At what scale should surface hydrologists and climatologists meet to begin this process? Perhaps the proposal should be accepted that they can meet best at the mesoscale, at which the planetary boundary layer processes spatially integrate smaller-scale variation in energy and mass transfer fluxes from the land surface. -from Authors

The fourth phase of IHP (1990-1995) - IHP IV - has been divided into three subprogrammes, including (H) Hydrological research in a changing environment. The objectives of sub-programme H are: to improve knowledge of the process involved in the hydrological cycle and to determine the manner in which these processes might be most appropriately described to meet the demands for planning, design, construction, maintenance and operation of water management schemes within changing environmental situations including the possibility of climate change; and to provide in cooperation with the international scientific community a general framework for the national, regional and international development of hydrology and related water sciences. Sub-programme H has several themes including: interface processes between atmosphere, land and water systems (Theme H-1). Theme H-1 includes Project H-1-1: Review of the scientific aspects of the interface processes of water transport through the atmosphere-vegetation-soil system at an elementary plot, catchment and grid size scale. -from Authors

Over 70 wide ranging papers (abstracted separately) were presented at the symposium and are contributions of the hydrologic atmospheric sciences to the IBGP Core Project BAHC and to the IHP prject H-1-1. The papers are grouped into 13 sections including: terrain evaporation dynamics; water/heat fluxes; soil flux transport; hydrological modelling; land surface process scaling; remote sensing techniques; hydrology and climate; spatial variability of precipitation and evaporation. -R.Gower

Rain angle and direction were measured using four variations of the Rose-Farbrother vectopluviometer and a new device called a pole vectopluviometer. Gauge wind loss and gauge wind interference related to wind speed, direction and rainfall intensity caused substantial differences in the rain angle and rain direction estimates between the different vectopluviometers. Although no absolute standard device exists, the pole vectopluviometer, a fluted pole divided into four sectors, provided the estimates of rainfall direction which most closely agreed with anemometer data and is intrinsically able to estimate average rain angle independently of direction. © 1991.

Meso-scale atmospheric systems are either forced by the instabilities of larger scale synoptic disturbances or they are induced by terrain. Terrain factors include topography, vegetation and land use. The variability in these atmospheric systems has temporal and spatial components of importance to agriculture in the world's semiarid regions. This review: i) discusses statistical and physical modelling approaches used in the analysis of meso-scale climatic variability; ii) reviews several monitoring approaches based on remote sensing; and iii) emphasises the need to integrate these different approaches. -from Authors

Reports on the evaporation measurements obtained with the Bowen ratio method at four sites in the Lockyersleigh catchment. It provides complete listings of the Bowen ratio data obtained on 42 days in 1987-89. This document also lists the additional surface temperature and windspeed data obtained for use with the simple one-layer resistance model described by Kalma and Jupp (1990). The results of this model application are presented in some detail. -from Authors

Rain angle and direction were measured using four variations of the Rose-Farbrother vectopluviometer and a new device called a pole vectopluviometer. Gauge wind loss and gauge wind interference related to wind speed, direction and rainfall intensity caused substantial differences in the rain angle and rain direction estimates between the different vectopluviometers. Although no absolute standard device exists, the pole vectopluviometer, a fluted pole divided into four sectors, provided the estimates of rainfall direction which most closely agreed with anemometer data and is intrinsically able to estimate average rain angle independently of direction. -Authors

The project aims to develop a series of maps by remote sensing to monitor aspects of the regional hydrology of the Murray-Darling Basin as well as its properties as a hydrothermal (water/energy) system. The methods are based on the analysis of thermal and microwave data collected by satellites to extract information on surface temperature and emissivity and thereby to estimate the spatial and temporal variation of soil moisture, rate of evaporation, water balance and associated properties of the root zone at a regional scale. © CSIRO 1990.

A one-layer resistance model has been used with infrared thermometry to estimate sensible and latent heat flux in pastures near Goulburn, New South Wales. The model compares reasonably well with energy balance-Bowen ratio measurements. However, the relative error in the evaporation estimates becomes significant in very dry conditions and at low net radiation values. An aerodynamic surface temperature may be computed from independent sensible heat flux measurements, air temperature measurements and estimates of aerodynamic resistance. The differences between computed and observed surface temperatures show characteristic diurnal trends and vary between days of measurement. These differences may be caused by errors in measuring the sensible heat flux and the surface temperature and in estimating the aerodynamic resistance. The pasture data obtained in this study are used to assess such uncertainties. The major cause for differences between the computed and observed surface temperatures is considered to be the incompleteness of the vegetative cover during each of the experimental periods. The measured Ts values apply to both the vegetation and the soil surface, whereas the observed T0 values are based on a model which assumes complete cover and only considers foliage temperature. Finally, the two-layer model of Shuttleworth and Wallace is used to show that the relationship between the measured infrared surface temperature and the canopy air temperature depends on the aerodynamic resistances, the fractional vegetated area and the temperature differences between foliage, canopy air and soil surface. © 1990.

Minimum air temperatures were measured during three winters with a network of stations in open, undulating terrain. It was observed that the change in minimum air temperature with elevation could be predicted from mean nighttime windspeed, total nighttime net radiation loss and a hill-top reference minimum temperature. It was also found that the deviation of temperatures at individual sites could be predicted from a local terrain parameter which reflects the extent of cold air accumulations. Thus a methodology for frost risk mapping has been developed which is based on regional weather data and local terrain analysis. This paper describes the model and illustrates the regional weather and terrain effects with three-dimensional block diagrams. © 1990 Springer-Verlag.

A regional water balance study has been carried out in 1986-1990 in a 27 km2 catchment in the Goulburn-Marulan region in New South Wales. Field measurements and observations have been made of water balance components at a range of spatial and temporal scales. Reports in detail on the soil moisture monitoring program based on Neutron Moisture Meter measurements. It describes the calibration procedures used and provides a complete set of three and half years of soil moisture data obtained at approximately two-week intervals along three transects with 13, 16, and 15 measuring points, repectively. This Report also provides the associated rainfall data obtained at three automatic climate stations. -from Authors

The present paper on air temperature, discusses some of its determinants and then reviews temperature measuring techniques. The second part is particularly concerned with the spatial extrapolation and interpolation of temperature data. A brief reference is also made to problems of temporal extrapolation. In the final section, some recent experiences with remote sensing techniques are discussed to illustrate their potential utility in local climate studies. -Author

Resistance-energy balance methods for estimating evapotranspiration have been widely used with remotely sensed surface temperatures obtained with ground-based or airborne infrared thermometers, as well as thermal sensors in satellites. However, serious problems are associated with the determination of appropriate aerodynamic resistances (ra)H, ie the diffusion resistance to sensible heat transfer between the vegetation or soil surface and some reference height. In this note several widely used expressions for (ra)H are compared using published wheat data from Phoenix, Arizona. -Author

The proceedings comprise the full text of 24 papers and abstracts of two. They are arranged by session theme: recognition of basic problems and the need for data; new approaches to the application of climatic and hydrologic data - the need for training; methods for extending the utility of climatic and hydrologic data; assessment of climatic or hydrologic hazards in agricultural production; application of various water balance and crop growth/development models which draw on climatic and hydrologic data; availability, quality and accessibility of data for agricultural applications. Reports on plenary discussions, and an overview of group discussions are included. Some of the papers are on Australia. All are abstracted separately. -from Editors

Laplacian smoothing spline functions have been used in a detailed spatial analysis of monthly and annual mean windspeed values in Tasmania. The techniques used here have been described in detail by Hutchinson et aL and the present paper significantly extends their results for Tasmania. The windspeed maps are discussed in detail with particular emphasis on their use for the assessment of Tasmania's wind energy potential Copyright © 1988, Wiley Blackwell. All rights reserved

The calibration of a commercially available infra-red surface temperature transducer is described. The instrument uses (i) a thermistor to measure the internal detector temperature and (ii) a thermopile to produce an output voltage, which depends on the temperature of the target surface and the internal detector temperature. Calibration results for the thermistor are shown to be in excellent agreement with the manufacturer's data. Three methods were used for calibration of the thermopile. The calibration results indicate that a single relationship between output voltage and the linear difference between target surface and internal detector temperatures, as proposed by the manufacturer, will lead to significant errors in measured target surface temperature. Theoretical considerations suggest expressions based on power functions of target and detector temperatures. The paper shows that such expressions result in significantly reduced errors, especially when the instrument is used over a wide range of detector temperatures. © 1988.

Seasonal and annual patterns of potential wind erosion in Australia are mapped. Potential erosion is estimated by applying Fryberger's sand drift potential concept to 3 p.m. wind data from 732 stations. Contour maps for January, April, July and October show monthly total drift potential, resultant drift potential, and drift directionality. Stream line maps show resultant drift direction. Annual resultant drift potential and drift direction are also mapped. Monthly total drift potential is maximal in October and minimal in April. Highest values occur on the coast, in the Nullarbor Plain, and in Tasmania; lowest values are scattered across the northern inland. Monthly resultant drift potential is similarly distributed. Monthly drift directionality is higher in the north. Monthly drift direction stream lines mainly express the general circulation of the atmosphere. Some local disturbances occur over ranges; others have cyclonic form. Annual resultant drift potential stream lines are broadly confluent and have anticyclonic curvature. These maps of potential wind erosion, linked to measures of erodibility, provide a basis for studying wind erosion hazard in Australia. Copyright © 1988 John Wiley & Sons, Ltd

Minimum air temperatures were measured at 31 sites in a 170 km2 region of undulating grazing land on 30 winter nights in 1982. The change in minimum temperature with elevation (dT/dz) could be predicted from mean night-time windspeed, total night-time all-wave radiation loss and the minimum air temperature at an exposed hill site. A multiple regression model is used which includes an interaction term for windspeed and net radiation. Excellent agreement between dT/dz values obtained with the 31 thermometer sites and a seven-site Ross recorder network was observed for 24 nights. The above regression model was then further developed with data for seven Ross recorder sites available for 86 days representing a much wider range of weather conditions. The improved model explains some 75% of the variation in minimum air temperature. Sites in convex terrain were consistently warmer and sites in concave terrain were consistently colder than predicted with the above model. A second relationship was therefore developed which predicts mean departures from the above regressions for individual sites from two simple terrain parameters: slope and catchment area. This regression explains 76% of the variation in the residual values. The combined weather-terrain model has been tested successfully with Ross recorder data from eight sites in 1980 (n = 246), 10 sites in 1981 (n = 189) and seven sites in 1982 (n = 602). © 1987.

A regional water balance study is in progress with objectives: 1) to develop reliable techniques for estimating daily totals of regional evaporation from remote sensing data and standard meteorological information; and 2) to develop a catchment management model to predict the effect of land use/land cover changes on regional water balance components. -from Authors

Measured surface wind patterns in the Canberra region of southeastern Australia have been used to derive a mean regional surface wind based on three-hourly means from 17 sites over an area of 600 km2. Additionally, three-hourly observations of the wind at 850 mb for one location in the region have been taken to represent the gradient wind over the region. Linear regression for an angular variate has been used to develop equations between the regional surface wind direction and variables defining diurnal and seasonal changes under varying synoptic conditions for each of the eight compass directions of gradient wind. -from Authors

Minimum air temperature measurements and airborne thermal scanner measurements of apparent surface temperature were obtained in a regional frost risk study in gently undulating grazing country in the Southern Tablelands of New South Wales, Australia. The minimum air temperature data obtained at 7 sites on 100 nights have been used to derive a predictive relationship between temperature lapse rate and night-time wind speed and net radiation loss. An extended network was used on 30 nights using an additional 24 sites. Excellent agreement was observed between the lapse rates collected from both the 7-station and 31-station networks on 24 nights. Maps of minimum air temperature across the region have been obtained for selected individual nights using Laplacian smoothing spline functions based on elevation and map co-ordinates. Thermal scanner data were obtained with an aircraft on two nights and the paper presents detailed comparisons between apparent surface temperature data and minimum air temperatures obtained from the regional maps. These comparisons have made it possible to successfully distinguish between broad topographic controls and the effect of local surface characteristics, especially in the case of high-resolution thermal scanner data. Such local controls include the effects of trees, surface water and various man-made features, as well as very local topographic features such as narrow depressions, which are only noticeable from site surveys and detailed aerial photography. It is concluded that thermal imagery is an important aid in understanding spatial distribution patterns of night-time air temperatures and hence in regional frost risk assessment. Copyright © 1986 John Wiley & Sons, Ltd

Reports on the spatial variability of wind speed and wind direction for categories selected on the basis of time of day and the gradient wind speed and direction. The paper also presents equations which may be used as predictive tools. -from Authors

Field germination behaviour and seedbed environment of the annual legume Townsville stylo (Stylosanthes humilis) and the vigorous annual grass weed (Digitaria ciliaris) were studied at Katherine, Northern Territory. Previous studies of the population dynamics of these pastures had indicated the importance of the germination-establishment phase in maintaining S. humilis as a pasture component. Analysis of seed samples at the time of sward establishment showed that near complete germination of viable seed (in the case of D. ciliaris) and of soft seed (in the case of S. humilis) occurred in the early storm period before the onset of the wet season. Swards of both species generally resulted from a single, major germination wave often after an isolated rainfall. The seedbed environment at the time of major germination waves was studied in detail for 2 years and environmental models were used with historical climate records to calculate probability distributions of temperature and moisture over 16 years. The main determinants of the seedbed environment were storms (most often occurring in the period from late afternoon to midnight) and high solar radiation levels (70% > 20 MJ m-2 day-1 in the days after rainfall. Surface soil generally dries to -1.5 MPa by noon. Minimum night surface temperatures showed little variation (~25°C) and were followed by high surface temperatures the following day (> 35°C). The use of a simple water balance model showed a high chance (80% of events) of the top 40 mm drying to ¿ 1.5 MPa at the end of the second day following rainfall. Despite the low variation of annual rainfall at Katherine (cv of 20%) these self regenerating annual species have a high risk of seedling death. Germination and seedling establishment take place at a time of rapid fluctuations in surface moisture and seedbed temperature. The analysis of seedbed conditions indicated that intensive sampling of the seed population would be required in the early storm period to explain differential survival of the species and that laboratory work should concentrate on factors controlling speed of germination over short periods of available moisture (12¿20 h). Copyright © 1985, Wiley Blackwell. All rights reserved

This Memorandum is the fourth in a series of reports on the analysis of wind data obtained in the Canberra wind monitoring program. The present paper reports on the use of regression analysis to provide quantitative relationships between regional wind and simple broadly defined parameters. -from Authors

Data from the Heat Capacity Mapping Mission Experiment Satellite (HCMM) are used to plot lines of constant temperature at 1° intervals for the city of Melbourne and surrounding country. Using four individual scenes, the relationship between uncalibrated, i.e. relative, surface temperature and screen daily minimum air temperature at some 26 standard meteorological stations in the greater Melbourne region was studied. It was found that the relation between the two data sources is poor for the sites taken separately but that means of daily minimum temperatures for appropriately grouped meteorological sites show a consistent linear relationship with night-time HCMM data. The HCMM data also show significant variation in surface temperatures within short distances from meteorological sites and it is concluded that surfacc temperatures in such an area vary on a spatial scale that is large compared with the area sampled by a standard meteorological site but small compared with an HCMM pixel. The implications are that a number of sites arc needed to characterize a region independently of site-specific elTects (i.e. that appropriately grouped sites can under some circumstances be used for calibrating satellite thermal data) and that thermal imagery could provide criteria for the selection of new standard meteorological sites. © 1984 Taylor & Francis Group, LLC.

This paper introduces the first comprehensive wind speed and wind run maps for Australia. Maps for January, April, July and October based on analyses for all twelve months are presented and discussed. They show, in turn, the distributions of mean 9 a.m. and mean 3 p.m. wind speed at a height of 10 m, the distribution of the ratio between mean daily wind speed and the mean of 9 a.m. and 3 p.m. wind speeds and, finally, the distribution of mean daily wind run at a height of 2 m. The wind speed and wind run maps have been produced from Laplacian smoothing spline surfaces fitted to wind speed observations and to wind run observations and estimates at approximately 500 Bureau of Meteorology stations. The ratio maps, which may be used to estimate wind run from 9 a.m. and 3 p.m. wind speeds, have been similarly produced from data at just 73 Bureau of Meteorology anemograph stations but with independent validation at 68 stations which record both wind speed and wind run. The fitted surfaces are functions of latitude, longitude and a suitable transformation of distance inland from the coast. The degree of data smoothing imposed by the surface fitting procedure has been chosen to minimize for each surface the mean square predictive error estimate as measured by generalized cross-validation. Copyright © 1984 John Wiley & Sons, Ltd

Daily values of satellite derived reflectivity and daily totals of incoming solar radiation were obtained over a six-month period for a network of stations in tropical Queensland, Australia. A definite linear relationship was observed between the reflectivity of the earth-atmosphere system and the atmospheric transmissivity calculated as the portion of extraterrestrial radiation reaching the surface. The scatter in the relationship was largely due to variation in the number of satellite scans available each day and to variations in aerosol absorption. Using the regression model, the transmissivity of solar radiation has been calculated over the entire study region for the months of August 1982 and January 1983. The spatial variability of incoming solar radiation has been discussed. It was found that the spatial pattern is strongly dependent on topography and wind direction. Copyright © 1984 John Wiley & Sons, Ltd

The Goulburn Frost Study is based on a program of regional field measurements of climatic variables in the Goulburn-Marulan area. This Technical Memorandum describes the objectives of that study, the study region and field sites, the instrumentation and measurements. It also provides summaries of the synoptic weather conditions during the three experimental periods, as issued by the Bureau of Meteorology.-from Authors

A one-dimensional, time-dependent, initial-value planetary boundary layer model, as developed by T.N.Carlson and colleagues at Pennsylvania State University, is described. This meteorological/hydrological boundary layer model is used with remotely sensed surface temperature data to derive soil moisture availablity and thermal inertia, which essentially govern the partitioning of available radiant energy at the ground between evaporation and sensible heat fluxes.-from Authors

HCMM satellite thermal imagery is used in a detailed frost assessment in an important horticultural area near Melbourne, Australia. Good general agreement is found to exist between plots based on night-time HCMM data which show surface temperature differences across the study area and frost risk maps based on terrain and land cover. However, it is concluded that the HCMM data have insufficient spatial resolution for use in local frost mapping in the study area. Improved thermal resolution will make thermal imagery from future satellites an increasingly important tool in topo-climatology. Without such improvements, local frost mapping will, in the absence of climatic network data or mobile topo-climatological surveys, continue to depend on data from thermal scanners in aircraft and on detailed assessment of terrain and land cover. Copyright © 1983 John Wiley & Sons, Ltd

The main determinants of differences in residential energy use for space heating and space cooling arise from location, structure and design of dwelling and human behaviour. International, inter-regional and inter-household comparisons show that most available statistical data on residential energy use hide great complexity and must be disaggregated to identify real differences. Some differences are increasingly recognized as inequitous, that is, as disadvantageous to one or more groups and difficult or impossible to remove. Government energy policy mechanisms must be developed which do not increase existing inequities in the energy field, or create new ones. © 1982.

The results show that there are significant site differences, some of which are related to the local topography and site exposure. An important result at many sites is the significant frequency of night-time southerly winds, particularly in winter, which appear to be locally generated. Temporal changes in the wind regime during the data collection period are related to regional synoptic conditions.-from AuthorsEnglish

The synoptic situation is described with a six-category classification, as well as windspeed and wind direction at the 850mb level. The regional wind regime is taken to be the average of the windspeed and wind direction at the 17 data sites at a particular time. The comparison is based on data for each synoptic hour, excluding 9pm and midnight, over the entire 12-month data period.-from Authors

Apart from early studies by Griffith Taylor, very little work has been carried out to describe the variety of thermal environments experienced by man in Australia. Previous studies are reviewed and new models are developed to quantify energy exchanges at specific times of the year within a continuum of possible responses to maintain homeothermy. Maps are presented of cold and heat stress to naked man, of work rates to achieve neutrality, and of clothing insulation requirements. Estimates are also made of primary energy inputs necessary to reach comfortable indoor temperatures by space heating and cooling within standard housing. It is further suggested that the success of settlement is associated with the relevance of human responses to the thermal environment. Copyright © 1981, Wiley Blackwell. All rights reserved

If present global trends toward rapid urbanization continue, about 5000 new cities, each with a population of about half a million people, will be required by the turn of the century, most of them in developing countries. The authors of this article, using Hong Kong as a model, conclude that the energy costs of constructing and operating these cities over the next 25 years would amount to more than five times the 1973 world consumption of energy. This study of the flow and end-use of energy and other materials in Hong Kong, and the extrapolation to a global future, shows that rapid urbanization is a resource-expensive process. Conservation strategies and alternative solutions should therefore be developed, with consideration given to the ecological relationships between cultural and physical variables in each setting.

A field evaluation of an inexpensive two-channel temperature recording system based on the Ross recorder with data storage on commerical stereo tape cassettes is described. The system can, in its present configuration, operate continuously for up to two months. A description is also provided of a tape translator and an inexpensive small temperature screen. The system has been evaluated in field tests which include comparison with standard climatological equipment, inter-comparison of several recorders in the same location and several topo-climatological studies. Overall accuracy of the system is better than 0.5°C. Several current developments are discussed. © 1978 Springer-Verlag.

This paper is Part II in a series on the impact of energy use on the atmospheric environment in Hong Kong. A one-dimensional time-dependent energy budget model has been used to study the effect of land use and of artificial heat generation on the surface energy balance and near-surface climate. Both spatial and temporal variability in energy use are considered. It is shown that energy use as well as the physical nature of the surface have a major impact on urban (meso) climate. Implications of these findings for two-and three- dimensional boundary-layer models are discussed. © 1978.

A range of methods and assumptions is presented for drawing up complete energy budgets for individual consumption sectors and for the detailed study of the spatial distribution and seasonal and diurnal variation of energy use in Hong Kong. The energy use per capita in Hong Kong is just over one-third of that in the Sydney region, whereas the intensity of energy use per unit area in Hong Kong is nearly twice that in Sydney. Midwinter daily energy use in Sydney¿s City area reaches 49 percent of the incoming solar radiation whereas values of 180 percent are reached in the Hung Horn region of Hong Kong. © 1976, Taylor & Francis Group, LLC. All rights reserved.

It is shown with simple two-dimensional advective models that artificial heat generation in the Sydney area, on early mornings in July, is largely responsible for the downwind temperature increase over the city. The models predict the height of the mixing layer and also the temperature increase downwind which agrees favourably with observations. The models require the following information: (1) average wind speed, (2) lapse rate difference between the stable upwind atmosphere and the air layer over the city, (3) the upwind surface temperature, (4) the vertical thermal diffusivity upwind, and (5) artificial heat generation. Data on energy use in the Sydney area have been presented elsewhere. A sensitivity analysis has been performed to study the interaction between the input parameters and their role in modifying the city's atmospheric boundary layer. © 1974 D. Reidel Publishing Company.

Seasonal changes in net all-wave and long-wave radiation are discussed, as measured over three surfaces, one dominated by Townsville stylo, another by two annual grasses and a third consisting of bare soil. The short-wave reflection coefficient of these three surfaces has been discussed in Kalma and Badham (1972). Net long-wave loss during night-time varied between 3 and 12% and net long-wave loss over 24 h between 19 and 47% of total incident short-wave radiation. In general, wetting and rapid growth caused net long-wave loss, as a fraction of incident solar radiation, to decrease. Drought, maturing, lodging and senescence had the opposite effect. Differences between the three surfaces were related to cover, stand height, drought resistance and growth phase. A unique relationship was observed between daily atmospheric transmissivity and the ratio between daily totals of diffuse and total radiation. It is shown how daily net long-wave radiation, under all conditions, may be predicted from known daily values of atmospheric transmissivity and air temperature. Effective surface radiative temperatures, indirectly obtained from measurements with single-sided pyrradiometers, have been presented for the two vegetative surfaces for three representative days. Semi-empirical relations for estimating net all-wave radiation during daylight from incident total radiation were obtained from linear regressions computed, using hourly totals, for net all-wave radiation on incident total radiation for all three surfaces and six successive periods covering the experimental season. Three seasonal regressions for the individual surfaces are given, and are considered to have practical applicability in further studies. Finally, long-wave and short-wave components of the radiation balance are given as percentages of monthly and seasonal mean daily short-wave radiation income. © 1972.

Short-wave reflection (albedo) was measured for three agricultural surfaces at Katherine, N. T., Australia, between December 18, 1969 and March 28, 1970. The seasonal albedo value for the pasture legume Townsville stylo was 0.19, for a mixed stand of two annual grass species 0.22, and for bare soil 0.21. Albedo of dry soil varied between 0.20 and 0.22. Wetting could lower albedo to 0.14. Maximum albedos for Townsville stylo and grasses were 0.25 and 0.28. Minimum values (0.13 and 0.15, respectively) were found at plant establishment. Rapid increase in albedo was associated with periods of rapid growth (increasing crop cover and increasing leaf area index). Severe water stress occurred after February 20 and albedo for both vegetative surfaces consequently decreased through reduction in effective crop cover, maturing of inflorescences and gradual senescence. Diurnal variation in albedo for all surfaces can partly be attributed to the sensors used, but part of the increase is due to the nature of the surfaces themselves. The role of specular reflection and internal trapping is discussed. © 1972.

Measurements are given of radiative and aerodynamic characteristics of a typical mature orange orchard in Israel's coastal plain. Net radiation to the canopy can be calculated adequately for weekly periods and longer from global radiation and three radiative crop characteristics. The role of aerodynamic crop characteristics, e.g., in crop water use studies, has been discussed. Rainfall, wind run, air temperature and humidity of the air were measured at equivalent heights both in a climate station outside the orchard and above the tree canopy at the experimental orchard site, and the microclimatic modifications associated with the above characteristics are discussed. Rainfall differences were negligible, whereas wind run at the climate station is shown to be significantly under-estimated. Absolute differences in temperature never exceeded 2°C, while relative humidity of the air above the canopy was almost constantly 8% higher. Relationships are given for calculating the relevant crop and climate parameters from standard climatic data. The distribution of net radiation, wind flow, air temperature and vapour pressure throughout the day has been illustrated graphically. The canopy structure of the orchard is not homogeneous horizontally. The horizontal variations especially affect the transfer of mass, energy and momentum within the canopy. Attempts to simulate these processes within the stand are mostly based on one-dimensional models, assuming horizontal homogeneity. In this study one-dimensional models of Cowan (1968) for the absorption of net radiation and the alternation of windflow within the canopy have been tested. Reasons are given for model breakdown and the need for general three-dimensional models is stressed. © 1972.

By inserting on preselected channels a 50 hertz a.c. conductivity meter between system scanner and voltmeter, a.c. resistance-type sensors for soil water content and other variables can be made compatible with a d.c. automatic data logging system, since adequate matching can be achieved between response curves of most of such sensors and the reciprocal resistance response of the conductivity meter. © 1972.

Empirical methods for estimating the direct and diffuse components of known global radiation are examined in detail and are tested with data from Australia, Papua New Guinea, India, southern Africa and the Stanley Islands. Significant differences are observed between relations deduced in this study and those reported by Liu and Jordan as deduced from temperate zone data in the northern hemisphere. A simple model for atmospheric attenuation has been developed which produces a common basis for the two empirical estimation methods. In this model diffuse radiation is related to the depletion of the direct beam in the atmosphere by a forward scattering function coefficient (K), whose value for different regions, climates and important cloud categories is discussed. Theoretical curves are generated relating diffuse and direct radiation to total global radiation for several values of the coefficient K. © 1972 Springer-Verlag.

By harmonic analysis periodic sine-functions were fitted to long-term five-day averages of maximum and minimum temperature of the air at screenheight and of the top 2 cm of bare soil for Katherine, N.T., Australia. A good simulation of the observed annual trend in all four elements was obtained by considering the first two harmonics only. The inclusion of higher harmonics did not lead to any significant improvement. The annual variation of extremes, mean values and ranges of air and soil temperatures and mean annual interrelationships have been studied and the interaction between soil-physical characteristics, rainfall pattern and other weather parameters discussed. A number of characteristic periods could be identified in the interrelationships between the soil and air temperature extremes, which are also climatologically well defined. It was concluded that wetting and drying of the soil are the major factors in determining the thermal regime of the topsoil and hence play an important role in the interrelationships between soil and air temperatures throughout the year. Some agronomic implications of the present climatological outline have been illustrated with reference to characteristic features in the life cycle of the pasture legume Stylosanthes humilis H.B.K., now well established in northern Australia. © 1971.

Regular measurements of incoming and reflected global radiation and net radiation were taken both above and below the canopy of an irrigated orange plantation during one year. The results have been analyzed to show the diurnal and seasonal changes in the main components of the radiation balance. The mean albedo of the plantation throughout the year was 0·16, ranging from a minimum of 0·12 in late spring to a maximum value of 0·21 in late autumn. The reflectivity of a single layer of orange leaves was more than twice that of the entire canopy, indicating the importance of internal absorption of reflected radiation within the canopy. Over the year, 0·28 of the incident global radiation was radiated to space in net long-wave flux, slightly more during the day than the night. The seasonal variation in net long-wave loss at sunrise and sunset was relatively small and showed no clear seasonal trend. Summertime profiles of net radiation from above the canopy to the soil surface beneath the canopy, together with canopy leaf area measurements, were used to compute the extinction coefficient for the plantation. Measurements of the net and short-wave radiation fluxes at ground level, made at different times of the year, were analyzed to show the extent of seasonal changes in the transmission coefficient for both long- and short-wave radiation. Measurements of the soil heat flux show this to be a minor component of the energy balance; seasonal and diurnal variations in this flux are discussed. The annual sum of the radiation balance available to the canopy amounted to 56 per cent of the incident global radiation. The changing seasonal partition of radiation energy between latent and convective heat fluxes has been calculated for both above- and below-canopy conditions and the results show that the leaf surfaces offer a greater resistance to water-vapor diffusion than the bare soil surface beneath the leaf canopy. © 1969.

An accurate, inexpensive, small-orifice rain gage (modified Victor-rain gage) with an orifice diameter of 29.2 mm was developed for use in rainfall networks and in agrometeorological and hydrological studies. It has a large capacity and can be installed and read easily. Comparison with standard rain gages showed good agreement under various conditions of exposure and with different observation techniques. Small amounts of rainfall are likely to be overestimated, owing to a film of water adhering to the glass water container of the gage, whereas hail tends to be underestimated. If the gage is intended for storage, the funnel tube has to reach nearly to the bottom of the inner vessel. Copyright 1969 by the American Geophysical Union.

The three constants of a radiation-balance equation - albedo, heating coefficient and long-wave radiation balance at zero insolation - have been derived from linear regression equations relating measurements of incident and reflected short-wave radiation to measurements of radiation balance (all wave-lengths) made over nine different associations of natural vegetation and two agricultural surfaces. Albedo was found to be the most important discriminant in the relationship, varying from 0.12 for a pine forest to 0.37 for vegetation in a desert wadi. The diurnal and seasonal variations were small and of limited significance. The heating coefficient varied considerably, both with date of measurement and with vegetation, but no consistent differences could be seen. The values found were very low, even negative on a number of occasions. These were associated with a mid-day decrease in the long-wave balance attributed to a marked increase in the long-wave flux from the sky. The long-wave balance at zero insolation also varied considerably with date of measurement and type of surface but showed only small differences in long-term mean values. Daily totals of net radiation balance expressed as percentages of total incoming short-wave radiation varied from a maximum of 58 per cent for the open water surface of a fish pond to a minimum of 25 per cent for a desert association. The ratio for most vegetation was close to 50 per cent. Copyright © 1966 Royal Meteorological Society

Considerable difficulties have been reported in the use of single-layer canopy models for estimating evapotranspiration under partial and non-uniform vegetation cover. Two-layer models that distinguish between bare soil and vegetation are considered to provide a better characterization of the energy and mass transfers over such heterogeneous surfaces. This paper presents the application of one such two-layer model to a grassland catchment in NSW. The investigation has shown that, while the two-layer model is inherently superior to the single-layer models, considerable scatter is generated in practice because of uncertainty in the additional parameter inputs that the two-layer model requires. The parameters that were found to be most critical in this study were surface soil moisture, soil heat flux and stomatal resistance.

Two simple surface temperature models for predicting evaporation are described with results of their use in pasture. First, a simple daily model when compared with a water balance method was found to be inadequate in accounting for seasonal differences in soil moisture and vegetation condition. Second, an hourly one-layer resistance model gave reasonable results when compared with Bowen ratio measurements.

Low-cost battery-operated psychrometers have been developed for use in climate stations and evaporation studies. These instruments are based on the WMO reference psychrometer. The paper gives design details and provides some results of indoor- and outdoor comparisons between the reference psychrometer and the low-cost versions.

Rain angle and direction have been measured using four variations of the Rose/Farbrother vectopluviometer and a new device called a pole vectopluviometer. This paper presents intercomparisons and discusses possible errors.

Salinization is a widespread problem in the Murray-darling Basin of Australia resulting from extensive clearing for grazing, cropping and irrigation since European settlement in the last 200 years. The problem can attributed to increased recharge into regional and local groundwaters through the change in the water balance caused by the clearing and change in the land surface structure. Up to 10 years of AVHRR data are being analysed to investigate whether thermal remote sensing combined with GIS data integration and physical modelling can derive practical management oriented information for location and monitoring of anomalous effects in regional hydrology attributable to the ground and surface water interactions at the base of the salinity problem.