Michael J Savage

University of KwaZulu-Natal (Pietermaritzburg) · Agrometeorology Discipline: School of Agricultural Earth and Environmental Sciences

Site-specific and accurate prediction of daily minimum air and grass temperatures, made available online several hours before their occurrence, would be of significant benefit to several economic sectors and for planning human activities. Site-specific and reasonably accurate nowcasts of daily minimum temperature several hours before its occurrence...

To enhance teaching and learning in agrometeorology and allied disciplines, a Web-based data and information system was developed. The system uses field-based agrometeorologcial measurements, from automatic weather, radiation and temperature stations, to collect and display near real-time and previous data in graphs/tables. An important feature is...

Fog is a potential source of water that could be exploited using the innovative technology of fog collection. Naturally, the potential of fog has proven its significance in cloud forests that are thriving from fog interception. Historically, the remains of artificial structures in different countries prove that fog has been collected as an alternat...

It is imperative to possess a comprehensive understanding of the water consumption patterns of sweet cherry trees under rainfed conditions. This study investigates the water use of sweet cherry using the heat pulse velocity sap flow method. Tree response to drying soil conditions over two consecutive measurement periods (September 2017 to December...

Climate change impact assessment along with adaptation measures are key for reducing the impact of climate change on crop production. The impact of current and future climate change on maize production was investigated, and the adaptation role of shifting planting dates, different levels of nitrogen fertilizer rates, and choice of maize cultivar as...

Evapotranspiration (ET) is widely considered the main consumptive water use in agricultural production and its accurate determination enables crop producers to make informed decisions. Field experiments were conducted in KwaZulu-Natal, South Africa to estimate soybean ET from sensible and latent heat flux obtained using the surface renewal (SR) met...

The agriculture sector in Africa is dominated by small-scale farmers who account for about 80% of the total farms. However, small-scale farmers are vulnerable to climate change and climate variability. Their high susceptibility to climate change emanates from their inadequate ability to adapt to climate change. As a result, small-scale farmers are...

Global warming is widely recognised, and its effects are becoming apparent throughout the world. Evaporation and evapotranspiration, the key components of the hydrological cycle, are generally expected to increase due to the rise in air and surface temperatures. However, previous studies suggest a decrease in these phenomena despite the observed gl...

Study region Cathedral Peak Research Catchments, uKhahlamba Drakensberg mountain range, South Africa. Study focus The focus was to determine the seasonal pattern of evapotranspiration (ET) over a bracken canopy, which is a product of degradation within the montane grasslands of the uKhahlamba Drakensberg mountains. Surface renewal (SR) was investi...

South Africa is continuously experiencing significant irregular climate attributable to both climate change and the El Niño Southern Oscillation (ENSO). Air temperature increases, sporadic precipitation patterns and increased frequency of extreme events are expected across the region. Agricultural production, either rainfed or irrigated will be aff...

Accurate quantification of net irradiance of open water (Rn water) is of paramount importance for the estimation of open water evaporation, which is critical for the efficient management of water resources. Alternatively, model estimates of Rn water are often used when quality measurements of Rn water are not readily available for the water storage...

Maize is a staple crop in South Africa and is mainly grown under rain-fed conditions. Rain-fed agricultural production is heavily reliant on rainfall during the planting season. Information on rainy season characteristics is of utmost importance as it guides farmers in preparing for the upcoming season. The study investigated rainy season character...

Climate change projections of increases in lightning activity are an added concern for lightning-prone countries such as South Africa. South Africa's high levels of poverty, lack of education, and awareness, as well as a poorly developed infrastructure, increase the vulnerability of rural communities to the threat of lightning. Despite the existenc...

Process-based crop models are popular tools to quantify the impact of changes due to climate or crop management. Accurate simulation of crop production for different agro-ecological conditions using an individual crop model remains challenging due to different sources of uncertainty. Studies with ensembles of crop models can give valuable informati...

Climate change projections of increases in lightning activity are an added concern for lightning-prone countries such as South Africa. South Africa’s high levels of poverty, lack of education and awareness, as well as a poorly developed infrastructure increases the vulnerability of rural communities to the threat of lightning. Despite the existence...

Eddy covariance (EC) systems are expensive and not financially viable in a budget-restricted hydrological monitoring network. The surface renewal (SR) method is a cheaper alternative that requires a reduced fetch, but is currently dependent on EC for calibration. The SR methods not requiring calibration (SR2 and SRDT) have been used, but are not wi...

Rainfall and air temperature variability pose the greatest risk to environmental change. Past trends in rainfall and air temperature facilitate projecting future climate changes for informed policy responses. We used a combination of the normalised difference vegetation index (NDVI) and observed data from 1968 to 2017 to assess changes in rainfall,...

Globally, lightning causes significant injury, death, and damage to infrastructure annually. In comparison to the rest of the world, South Africa has one of the highest incidences of lightning-related injuries and deaths. The latest available lightning detection techniques and technologies are reviewed and include current research in South Africa a...

The past few decades have produced a wealth of research investigating the extent and severity of global climate change. Patterns in climate variability and change have been studied at global, continental and regional scales. Trends observed at these larger spatial scales are expected to be observable at smaller scales, although research in this reg...

Reliable estimates of daily, monthly and seasonal soil moisture are useful in a variety of disciplines. The availability of continuous in situ soil moisture observations in southern Africa barely exists; hence, process-based simulation model outputs are a valuable source of climate information, needed for guiding farming practices and policy interv...

Evapotranspiration (ET) plays a crucial role in the land-atmosphere interaction and climate variability, especially in arid and semi-arid areas. Accurate estimates of ET are important in hydrological and climate modeling. This study evaluates eight ET data products from different models used for ET estimation. The data products are classified into...

A wealth of information on the extent and severity of global climate change has been produced through research over the past few decades. Global trends of the climate should be observable at a regional and local level, yet certain areas remain under-represented in both national and international research. This study presents an investigation into t...

Global irradiance is an important natural resource which is fundamental in various processes. Direct observations of components of global irradiance are scarce globally and models are required to improve their spatial coverage. Using a 30-year dataset, this study investigates relationships between measured global irradiance and diffuse irradiance a...

Traditional timer-based systems for irrigation management, which are more commonly used in commercial nurseries in South Africa, are not ideal as they may not irrigate seedlings efficiently. A sensor-based irrigation system is presented as an alternative, as this can provide several benefits to nurseries and nursery-grown seedlings. Small-sized soi...

ABSTRACT Meteorological series (daily precipitation, minimum and maximum air temperature) for Asmara (Eritrea) for the last hundred years (1914 – 2015) are analysed. The data were quality controlled and homogenized using publicly available data from surrounding countries as well as newly recovered data from twelve stations in Eritrea. Overall, the...

Simpler crop models simulating evaporation are needed to provide information to farmers, policy makers and decision makers on how to maximise crop yield responses to water. This is becoming important as the frequency and severity of droughts in South Africa is increasing. In this regard, prediction of yield, determination of water productivity and...

Reliable estimates of daily, monthly and seasonal soil moisture are useful in a variety of disciplines. The availability of continuous in situ soil moisture observation records in Southern Africa barely exists. In this regard, process based simulation model outputs turns out to be a valuable source of climate information, which is needed for guidin...

Central Africa is a global lightning hot spot, with the tropical areas including the top 10 highest lightning-flash-rate densities in the world. There are no lightning-locating-system networks available across most of Africa, however, and it becomes necessary to make use of real-time, ground-based lightning early warning systems. Such a system was...

Various Word and PowerPoint templates for Masters’ dissertations, PhD theses, long documents and slide presentations. For all templates/documents see: https://www.dropbox.com/sh/kqegd6qqzw1oecu/AAAuXvO0oUc7CWwf23rXTWFDa

Surface-layer scintillometer (SLS) measurements and inputs of beam height above the zero-plane displacement height, air temperature, atmospheric pressure and direction of sensible heat flux are used to calculate sensible heat and momentum fluxes using MOST and an iterative process. See my video channel to check for a possible video on this spreadsh...

Spreadsheet analysis for linear regression statistics model evaluation, prediction of x from y or y from x and suspicious point analysis

Daily short-grass and tall-crop reference evaporation and their components using Excel VBA. This version allows for a long set of data as input. A simple method of obtaining from daily evaporation the weekly and monthly evaporation values is demonstrated. For instructions on the use of a similar spreadsheet, see: https://youtu.be/qDU41skJByk

Daily short-grass and tall-crop reference evaporation and their components using Excel VBA. A simple method of obtaining from daily evaporation the weekly and monthly evaporation values is demonstrated. For instructions on the use of a similar spreadsheet, see: https://youtu.be/qDU41skJByk

A spreadsheet for calculating humidity, including the wet-bulb, using the Newton-Raphson iterative method in Excel VBA. For instructions on the use of this spreadsheet, see: https://youtu.be/jmydREU0GT0

From datalogger air temperature structure function outputs, Excel VBA is used to calculate the van Atta roots of a depressed cubic polynomial and hence the surface renewal sensible heat flux. For instructions on the use of this spreadsheet, see: https://youtu.be/mFOZSuqsLHI

Humidity and heat index calculations in Excel

Short-grass and tall-crop reference evaporation and their components using Excel VBA. A simple method of obtaining from hourly evaporation the daily, weekly and monthly evaporation values is demonstrated. For instructions on the use of this spreadsheet, see: https://youtu.be/qDU41skJByk

Validation for the calculations of short-grass and tall-crop reference evaporation and their components is demonstrated using Excel VBA. For instructions on the use of this spreadsheet, see: https://youtu.be/qDU41skJByk

From datalogger air temperature structure function outputs, a simple iterative method in Excel VBA (based on Savage, 2017, Journal of Hydrology 547: 742–754) is used to calculate the van Atta roots of a depressed cubic polynomial and hence the surface renewal sensible heat flux. For instructions on the use of this spreadsheet, see: https://youtu.b...

From datalogger air temperature structure function outputs, Excel VBA is used to calculate the van Atta roots of a depressed cubic polynomial and hence the surface renewal sensible heat flux

Humidity and heat index including wet-bulb iteratively using the Newton-Raphson method in VBA Excel: RHCALCi

Excel VBA spreadsheet to obtain short-grass and tall-crop reference evaporation and their components

Humidity and heat index calculations in a spreadsheet

Wildfires are considered one of the most common disasters in southern Africa resulting in a high number of human fatalities and financial loss on an annual basis. It is believed that increased population growth, as well as more concentrated settlement planning, is likely to result in increased fire disasters and increased human fatalities as a dire...

Efficient nursery irrigation is a key factor for the production of high-quality forestry planting stock. Conventional timer-based irrigation systems used by most forestry nurseries have some drawbacks that, if not properly managed, can lead to over-irrigation and water wastage, leaching of nutrients and contribute to increased incidences of pests a...

The estimation of evapotranspiration (ET) is essential for meteorological modeling of surface exchange processes, as well as for the agricultural practice of irrigation management. Hitherto, a number of methods for estimation of ET at different temporal scales and climatic conditions are constantly under investigation and improvement. One of these...

The soil and water assessment tool (SWAT) was calibrated for the Luvuvhu River catchment, South Africa in order to simulate runoff. The model was executed through QSWAT which is an interface between SWAT and QGIS. Data from four weather stations and four weir stations evenly distributed over the catchment were used. The model was run for a 33-year...

Fog can be considered a potential water resource for certain semiarid and arid countries. In Eritrea, a fog-water collection project was implemented in 2007 in the villages of Arborobue and Nefasit. This study presents an assessment of the project after five years of implementation and identifies the main strengths to be technical viability, since it...

Landfill sites are known for their potential for generating particulate matter (PM) which can pose respiratory health problems for people residing in the adjacent communities. As PM2.5 have health impacts on children residing close to landfill sites, it is important to understand the extent to which they are affected. In this investigation, PM2.5 m...

The influence of climate change on wildfires has been studied at a global scale, but uncertainties on the influence at regional and hyper-regional level still exist. As the KwaZulu-Natal (KZN) midlands rely heavily on agro-forestry and tourism to support the local economy, changes in fire dynamics need to be taken into consideration. This study aim...

Current changes in global climate are likely to be evident at both the regional and the local scale. This study presents an investigation in climatic trends in the KwaZulu-Natal (KZN) midlands, South Africa and seeks to assess the level of change in the microclimate and more specifically, the influence of a changing climate on fire danger. To this...

Estimation of reference evapotranspiration (ETo) is crucial in crop production practices and other hydrological processes. The hourly FAO-56 Penman-Monteith (EToPM) method was used to calculate ETo at Bergville, Bethlehem and Harrismith in the eastern Free State, South Africa. Priestley-Taylor evapotranspiration coefficients (PTc) were estimated us...

An iterative method was applied to daily crop reference evaporation ETo. The method correctly evaluated the slope of the saturation water vapour pressure vs temperature relationship between surface temperature and air temperature. Using daily meterological data spanning several decades from four selected locations in Australia, South Africa and USA...

The prevalence and history of fires in Africa has led to the continent being named ‘the fire continent’. Fires are common on the continent and lead to a high number of annual fire disasters which result in many human fatalities and considerable financial loss. Increased population growth and concentrated settlement planning increase the probability...

Eucalyptus smithii is an important commercial forestry species in South Africa. The species’ shy and erratic flowering tendencies hinder its genetic improvement and seed production. Breeders and seed producers are highly dependent on paclobutrazol (PBZ) applications for encouraging flower and seed production in E. smithii orchards. During the summe...

Winter chilling is a key environmental trigger of floral induction in temperate Eucalyptus. Over the past two decades, considerable site×eucalypt flowering interaction research has been undertaken over a range of high elevation (>1 100 m asl) forestry sites in the South African summer rainfall area. A practical method of accurately monitoring eucal...

Fog is an untapped natural resource. A number of studies have been undertaken to understand its potential as an alternative or complementary water source. In 2007, a pilot fog-collection project was implemented in 2 villages on the Eastern Escarpment of Eritrea. The government of Eritrea, buoyed by the project’s positive results, has encouraged res...

Commercial forestry nursery managers currently use a timer-based system to irrigate their planting stock. However, this method does always result in efficient scheduling of irrigation, and automatic measurement and control of irrigation using sensors may be an alternative. In this study, the effectiveness of an automated irrigation system was inves...

There is a global trend to high intensity horticulture, including high density plantings, use of superior cultivars, greater plant manipulation, and protected cultivation. e avocado industry is lagging in the use of the latter. Two shadenet structures were erected over existing orchards. e rst in the warm, dry subtropical area of Mooketsi (Limpopo)...

There is a global trend to high intensity horticulture, including high density plantings, use of superior cultivars, greater plant manipulation, and protected cultivation. The avocado industry is lagging in the use of the latter. Two shadenet structures were erected over existing orchards. The first in the warm, dry subtropical area of Mooketsi (Li...

There is a global trend to high intensity horticulture, including high density plantings, use of superior cultivars, greater plant manipulation and protected cultivation. The avocado growers have only recently started using protected cultivation and still need to determine the technical details of this type of cultivation. Shade netting has shown t...

The agricultural sector is one of the crucial sectors heavily impacted by the consequences of water scarcity. Improved water resources management in croplands is important as available water resources become scarcer. Evaporation and transpiration are important processes in the hydrological cycle. Their quantification remains one of the important ch...

Spatial variations of microclimatic conditions in enclosed north–south (N–S) oriented single-arched greenhouse polycarbonate structures, with a wet-wall providing evaporative cooling at the S end, were investigated and displayed online in near real-time. Temperature-controlled fans at the N end extracted air. Air temperature, wind speed and water v...

How to interpret meteorological measurements made at a given level over a surface with regard to characteristic properties such as roughness, albedo, heat, moisture, carbon dioxide, and other gases is an old question which goes back to the very beginnings of modern micrometeorology. It is made even more challenging when it is unclear whether these...

Agrometeorology, as an applied technological discipline, is initially challenging to undergraduate students and even postgraduate students. In addition, many of the students have a first language for which the words 'meteorology' and 'agrometeorology' do not exist. The teaching of agro-meteorology presents significant challenges due to the use of m...

Eucalyptus nitens requires a sufficiently cold winter to produce flower buds. In areas in South Africa where E. nitens commercial plantations as well as breeding and production seed orchards are located, winter chilling is often insufficient for floral bud initiation. Hence, under such conditions, E. nitens floral bud and seed crops are poor and in...

The objectives of this research included the development of a system for improved monitoring of meteorological conditions conducive to fire. The nomogram and lookup table lowveld fire danger index (FDI) system was replaced by mathematical functions programmed into a datalogger. Near real-time results of FDI were displayed in a web-based teaching, l...

Accurate air temperature measurements are required for many different purposes, including global warming impacts. Temperature methods used in this study included: Stevenson screen, 6-plate Gill shield, radiation-shielded and aspirated systems, and unshielded and naturally ventilated 25- and 75-micrometre fine-wire thermocouples. The 25-micrometre u...

Quantity and spectral quality of radiation is important when growing plants under protection (tunnels) and particularly for vegetative propagation due to the varying effect of the radiation spectrum on plant morphology. Five coloured shade nets and two plastics were evaluated with regard to their transmission of radiation and alteration of spectral...

INTRODUCTION Protected environment structures such as greenhouses and shadenetting are an option to address the problem of many weather hazards and improve control of the microclimate. Evaporative cooling may be an option to reduce inside temperatures. In this study, that utilises a web-based data and information system for sharing of measurements...

The measurement of leaf wetness duration (LWD) was investigated using subhourly dielectric, infrared surface temperature, dewpoint temperature, grass temperature and relative humidity (RH) measurements. Near real-time LWD data and information displays and alerts were made available timeously via a web-based system. LWD was estimated above a short-g...

The estimation of frost duration (FD) was investigated using dielectric, infrared surface temperature and grass temperature subhourly measurements. Near real-time FD data and information displays and alerts were also made available via a web-based system. FD was estimated using a dielectric leaf wetness sensor (LWS) method, for which the sensor vol...

Fog is considered as an alternative water resource for fresh water in the eastern escarpment of Eritrea. This area is bestowed with high-altitude dense fog, which is formed during the uphill movement of adiabatically cooled humid air masses from the Red Sea. A pilot project was implemented in 2007 in the villages of Arborobue and Nefasit where the...

Competition for fresh water between agriculture and domestic and industrial uses is increasing worldwide. This is forcing subsistence and commercial agriculture to produce more with less water. Consequently, it is crucial to properly and efficiently manage water resources. This requires accurate determination of crop water loss into the atmosphere,...

INTRODUCTION Due to ever increasing pressure on water resources for irrigated agriculture, accurate estimation of evapotranspiration (ET) is vital. Within the past decade, accuracy of ET estimates has improved mainly due to new and increasingly sophisticated methods such as those based on micrometeorology. These methods include eddy covariance, Bow...

Surface fluxes of sensible heat and latent energy are important in many atmospheric processes and can be measured with reasonable accuracy over homogeneous surfaces. Direct measurements of turbulent fluxes such as sensible heat and latent energy, which are components of the shortened energy balance, are usually achieved by the eddy covariance (EC)...

Solar irradiance is fundamental in estimating evapotranspiration and dry matter production from agricultural fields. In general, testing of radiation interception models is limited by the number of measurement points both in space and time and the few crop species used. We considered many nodes (points of measurement), more than in any other publis...

To date, time spent grazing has been measured most successfully using an electronic grazing clock. Difficulties experienced with this clock however, were that temperature and stage in the life of the batteries affected the readings. Further, periods of grazing shorter than the units of time registered by the clock could not be recorded. This paper...

The possibility of reliable, reasonably accurate and relatively inexpensive estimates of sensible heat and latent energy fluxes was investigated using a commercial combination thin-film polymer capacitive relative humidity and adjacent temperature sensor instrument. Long-term and unattended water vapour pressure profile difference measurements usin...

For short canopies, latent energy flux may be estimated using a shortened surface energy balance from measurements of sensible and soil heat flux and the net irradiance at the surface. The surface renewal (SR) method for estimating sensible heat, latent energy, and other scalar fluxes has the advantage over other micrometeorological methods since t...

A dual-beam surface-layer scintillometer (SLS) was used to estimate sensible heat flux (H) every 2 min for a path length of either 50 or 101 m, for more than 30 months in a mesic grassland in eastern South Africa. The SLS method relies on Monin-Obukhov similarity theory, the correlation between the laser beam signal amplitude variances and the cova...

Harvesting sugarcane green and using crop residues as a mulch layer for the subsequent ratoon (instead of burning residues) is a desirable alternative production system. Knowledge of how residue layers affect microclimate, the surface energy balance, growth and sugarcane water use is limited. Surface energy balance fluxes namely net irradiance (Rn)...

Evaporation is one of the main components of the energy and water balance of reservoir water behind dams and is a major component of water loss. Measurements in winter of sensible heat (H) for the small and shallow reservoir of Midmar Dam, KwaZulu-Natal, South Africa were made using the surface renewal (SR) method, a renewal model method that uses...

A dual-beam surface-layer scintillometer (SLS) was used to estimate sensible heat flux (H) every 2 min for a path length of either 50 or 101 m, for more than 30 months in a mesic grassland in eastern South Africa. The SLS method relies on Monin-Obukhov similarity theory, the correlation between the laser beam signal amplitude variances and the cova...

Evaporation measurements using two Bowen ratio energy balance (BREB) systems in a remote high altitude montane grassland catchment of the Drakensberg Mountains, Cathedral Peak, South Africa are reported on. Various methods of data verification and rejection of inaccurate measured air temperature and water vapour pressure gradients are examined. A t...

A standard, convenient and accurate method for calibrating net radiometers would assist in unravelling reasons for the perplexing lack of surface energy balance closure as well as improving on the accuracy of the energy balance residual method for estimating evaporation. A relatively inexpensive, accurate and quick laboratory method for non-steady...