bluuebunny/crossref_metadata_2025 huggingface dataset:
Does the financial market lead the business cycle in South Africa?
Authors: Botha Ilsé
Published: July 2019

Financial markets play a significant role in an emerging market economy such as South Africa, especially after financial liberalisation. Financial liberalisation causes economies to interrelate across borders and between different sectors. The impact of this interrelationship can be captured by taking the different components of the financial market into account and relating these to the real sector, using the coincident indicator. It will be useful to identify an indicator representing the major components - equity market, capital market and the domestic financial sector - of the financial market in South Africa. This financial indicator will lead the coincident indicator, because the components of the financial indicator are available at a higher frequency than the components of the coincident indicator. This new indicator for South Africa will be of assistance in making more informed business decisions since it can be used to forecast turning points in the coincident indicator, i.e. the business cycle.
The value of accounting discourse in conditions of accelerating change
Authors: Hookana Heli
Published: July 2019

This study investigates the complex relationships between organisational strategic change, developing accountabilities, and materialised values in the emerging public-service network. The study highlights the importance of bilateral governance, relational forms of behaviour, and the voluntary exchange of information that is based upon shared values and that regulates networked behaviour in a much less overt way than formal attempts at control. In these circumstances accountancy basically serves as an assistant, helping to mediate, shape and construct inter-organisational relations through various socio-economic and discursive power-based mechanisms. The results indicate that for some organisations value-based management may still have elements of value-adding contributions of a more non-financial and social nature despite the veneer of the rhetoric. In combining participation in development work, work in practice, and theoretical analysis, the study carries both theoretical and practical implications.
The causal relationship between government revenue and expenditure in Namibia
Authors: Eita Joel H. , Mbazima Daisy
Published: July 2019

The relationship between government revenue and government expenditure is important, given its relevance for policy especially with respect to the budget deficit. The purpose of this paper is to investigate the relationship between government revenue and government expenditure in Namibia. It investigates the causal relationship between government revenue and government expenditure using the Granger causality test through cointegrated vector autoregression (VAR) methods for the period the period 1977 to 2007. The paper tests whether government revenue causes government expenditure or whether the causality runs from government expenditure to government revenue, and if there is bi-directional causality. The results show that there is unidirectional causality from government revenue to government expenditure. This suggests that unsustainable fiscal imbalances can be mitigated by policies that stimulate government revenue.
The value and accounting premium for South African-listed shares
Authors: Ernstberger Jürgen , Heinze Christian , Vogler Oliver
Published: July 2019

In the last decade, empirical research has found strong evidence that value stocks provide higher returns than growth stocks (value premium). Firms with a high ratio of book value of equity to market value of equity are regarded as value stocks; a low ratio identifies growth stocks. Most research is tailored to the market in the United States of America. Only a few studies consider country-specific distinctions. This research analyses the value premium for the South African market and compares its magnitude to the findings for the US market. Moreover, the effects of the introduction of International Financial Reporting Standards (IFRS) for companies listed at the JSE Limited are examined. The adoption of IFRS is used to demonstrate that investors award an accounting premium for voluntary compliance with this new accounting standard.
Do waiters get their fair share? A case study on the working conditions of waiters
Authors: Blaauw Derick , Viljoen Kotie
Published: July 2019

In 2007 the working conditions and remuneration of waiters in South Africa changed with the introduction of the Sectoral Determination 14, as an addition to the Basic Conditions of Employment Act no 75 of 1997. One important provision of the Sectoral Determination is the introduction of minimum wages for employees in the hospitality sector, including waiters. The aim of this paper is to investigate the working conditions and remuneration of waiters and to compare their actual working conditions with those stipulated by the above legislation. In order to achieve this aim, the research includes a literature review of the BCEA and Sectoral Determination as well as a survey amongst waiters in Kempton Park (South Africa), investigating the actual working conditions and remuneration of waiters. A comparative study of the actual working conditions is done and the results are compared with the available literature on the topic. From this analysis relevant policy recommendations are formulated.
Editorial
Authors: Els Gideon
Published: July 2019

No abstract available.
Accounting practitioners’ views on the proposed “Micro GAAP”: A South African perspective
Authors: Van Wyk Hentie A. , Rossouw Cobus
Published: July 2019

Even though the IFRS for SMEs does provide some relief in respect of the financial reporting burden for non-public entities, there still seems to be a need for an even lower level of financial reporting. In recent years South Africa embarked upon the development of a financial reporting framework for non-public entities and various versions of this so-called micro GAAP have been issued. However, the Accounting Practices Board raised some concerns about the then proposed micro GAAP. This article highlights the South African accounting practitioners’ views from different professional bodies on micro GAAP. They generally believe that micro GAAP will represent fair presentation and that the financial statements prepared under micro GAAP can still be regarded as general purpose financial statements. Furthermore, the majority of accounting practitioners believe that there is a definite need for a third tier of financial reporting in South Africa and indicated their preference of which entities may apply micro GAAP. Legal backing of micro GAAP is also considered appropriate by the practitioners.
Spatial price transmission analysis in Ghanaian agricultural markets: Does the data frequency improve our estimation?
Authors: Amikuzuno Joseph
Published: July 2019

Unavailability of high frequency weekly or daily data compels most studies of price transmission in developing countries to use low frequency monthly data for their analyses. Analysing price dynamics, especially in agricultural markets, with monthly data may however yield imprecise price adjustment parameters and lead to wrong inferences on price dynamics. This is because agricultural markets in developing countries usually operate daily or weekly, not monthly, as implied by the market analysts who use low frequency data. This paper investigates the relevance of data frequency in price transmission analysis by using a standard and a threshold vector error correction model to estimate and compare price adjustment parameters for high frequency semi-weekly data and low frequency monthly data obtained from five major fresh tomato markets in Ghana. The results reveal that adjustment parameters estimated from the low frequency data are higher in all cases than those estimated from the high frequency data. There is reason to suspect that using low frequency data, as confirmed in some literature, leads to an overestimation of the price adjustment parameters. More research involving a large number of observations is however needed to enhance our knowledge about the usefulness of high frequency data in price transmission analysis.
The effect of financial capital on inner-city street trading
Authors: Callaghan Chris
Published: July 2019

This study extends and tests conceptions offered by the nutrition model of efficiency wage theory into the informal street-trading context. Three street-trader samples from 2008, 2009 and 2010 were drawn from the Johannesburg city centre. Statistical parametric and non-parametric analysis was used for a longitudinal investigation of certain associations of initial investment, or the money investments of street traders at start-up. Partial correlation analysis was used for further analysis of the 2010 sample. Findings suggest that policymaker interventions might best target traders earning under a threshold of earnings of about R230 per day. More specifically, training might offer such traders insight into how to change their product offerings to products associated with higher returns. Further, any interventions that might raise street-trader earnings above this threshold might enable such traders to obtain a positive return on capital invested in the sector.
Die toepaslikheid van deeltitelheffings in Suid-Afrika
Authors: Smit Christiaan , Oberholzer Merwe , Ellis Suria
Published: July 2019

This study challenges the fairness of sectional title schemes’ levies that are ordered by the Sectional Title Act (95 of 1986) to be allocated according to the participation quota (floor area) of units. Studies have shown that larger units in a sectional title scheme tend to subsidise the levies of smaller units. A log-transformed linear regression analysis was performed to investigate the cost behaviour of 113 sectional title schemes. The results revealed that 86% of the variation in the operating costs of a scheme is attributable to the variation in the area of a scheme, while 87% of the variation in operating costs is attributable to a variation in the number of units in a scheme. The conclusion is that the area and the number of units in a scheme are equally significant drivers of operating costs. Therefore, the study recommended that the levies should be allocated on a 50/50 basis with regard to area and number of units.
In-school marketing in South African primary schools: An exploratory study
Authors: Cassim S. , McIntosh K.
Published: July 2019

In-school marketing is a global phenomenon that has recently become the focus of much debate and criticism. Concerns about the potentially negative impact marketing practices may have on school going children have been raised across the globe. In response a variety of policies have been developed in different countries to regulate the practice of in-school marketing. This paper explores commercial activities in South African primary schools through an empirical study of primary school principals. The study investigates the policies and procedures in place to guide the practice of marketing in schools and the views of principals on issues pertaining to in-school commercialism. The findings of this paper indicated an absence of formal policies to guide the practice of commercial activities in primary schools. Principals however supported the need for policies on in-school commercialism to protect children. They also expressed the view that commercial activities can only be tolerated when they offer added value to the school.
Varying cross-sectional volatility in the South African equity market and the implications for the management of fund managers
Authors: Raubenheimer H.
Published: July 2019

Modern portfolio theory is founded on an understanding of longitudinal volatility but it is the cross-sectional dispersion among investment returns that provide active portfolio managers with their competitive investment opportunities. The varying cross-sectional volatility in the South African equity market provides varying opportunity sets for active managers: the higher the cross-sectional volatility, the greater the opportunity for active risk taking, all other things being equal. This article argues that cross-sectional volatility must be considered hand-in-hand with risk limits and active risk targets when investment mandates are set and when mandated risk compliance is monitored.
Sources of negotiation power: An exploratory study
Authors: Dobrijevic G. , Stanisic M. , Masic B.
Published: July 2019

Power is a very important element of negotiation, because it gives advantage to one party over the other. Various tactics used by negotiators are either aimed at increasing their own power or decreasing the power of the opponent. This paper presents a conceptual analysis and research proposals that build on past research on power and negotiation. The main purpose of the present study was to investigate sources of negotiation power most used among business professionals. We have developed an extensive list of sixteen sources of negotiating power. In this exploratory study we used a qualitative approach based on semi-structured interviews. We chose purposive sampling in order to capture perceptions from different groups of negotiators. The results from thirty-one interviews show that need is the most relied upon source of power in any given situation, followed by perception, credibility, alternative, relationship, intangible factors, authority, material resources, and knowledge/information. Although qualitative research cannot be used to make generalisations about the entire population, this study should help negotiators to focus on the most probable sources of negotiation power and to prepare for negotiations adequately.
Financial instability and banks’ balance sheets: A note
Authors: Abraham H.
Published: July 2019

Following the recent financial crisis, it is sometimes argued that financial institutions should be regulated to a greater extent than before in order to prevent a recurrence of global financial crises. It is argued here that since banks create liquidity ex nihilo in exchange for financial collaterals whose nominal values are subject to market fluctuations, in general, banks’ regulation can have only a limited effect on the stability of the financial system. Monetary policy of central banks (i.e., setting short term interest rate) is essential to monitor asset prices and thereby create a stable financial environment.
An assessment of selected family business values in small and medium-sized family businesses
Authors: Van Der Merwe S. P. , Venter E. , Farrington S. M.
Published: July 2019

This study highlights the influence of selected business family values on the success of small and medium-sized family businesses. Success, for the purpose of this study, is measured using two variables, namely Harmonious family relationships and Perceived future continuity. The primary objective of this study is twofold: firstly, to identify the potential influence of selected business family values on the success of family businesses and secondly, to make practical recommendations on actions that families in business can take to ensure harmonious family relationships and the future continuity of their family businesses. The target population of this study was small and medium-sized family businesses in South Africa, and a total of 931 individual questionnaires were returned from 173 family businesses. The data collected was subjected to various statistical analyses, including exploratory factor analysis, calculating Cronbach alpha coefficients, and multiple linear regression analysis. The findings of this study show that the more family members perceive fair treatment in the family business, the more harmonious family relationships and perceptions of business continuity will be. In addition, the perceived level of trust, commitment and effective communication has a positive influence on family harmony and business continuity. This study has added to the empirical body of family business research, and provides an important first step in gaining insights into selected family business values that influence the effective functioning of family businesses.
Common Cutaneous Neoplasms in Patients with Immunodeficiency: A Case Series
Authors: Salihi Suhair Al , Mejbel Haider A , Prieto Victor G , Aung Phyu P
Published: July 2019

Through humoral and cell-mediated mechanisms, the immune system plays a vital role in protecting every organ system. Disorders of the immune system may result in various cutaneous manifestations, including cutaneous malignancies. In patients with immunodeficiency, the risk of development of malignant cutaneous neoplasms is substantially increased. This increased risk may be due to oncogenic viruses that find a suitable microenvironment for tumorigenesis and cancer development. A subset of cutaneous malignancies that develop in patients with immunodeficiency may show aggressive clinical and biological behavior. Here, we report six cases of highly aggressive and deadly cutaneous neoplasms that arose in patients with a known history of immunodeficiency: two cases of Kaposi sarcoma in patients with immunosuppression due to human immunodeficiency virus infection; a case of Merkel cell carcinoma and a case of squamous cell carcinoma (SCC) in patients receiving immunosuppressive drugs after organ transplant; a case of multiple cutaneous tumors, including invasive melanoma, SCC, and sebaceous carcinoma, in a patient with hypogammaglobulinemia and a history of organ transplant; and a case of basal cell carcinoma and melanoma in situ in a patient with primary immunodeficiency.
Mixing layer transport flux of particulate matter in Beijing, China
Authors: Liu Yusi , Tang Guiqian , Zhou Libo , Hu Bo , Liu Baoxian , Li Yunting , Liu Shu , Wang Yuesi
Published: July 2019

Abstract. Quantifying the transport flux (TF) of atmospheric pollutants plays an
important role in understanding the causes of air pollution and in making
decisions regarding the prevention and control of regional air pollution. In
this study, the mixing layer height (MLH) and wind profile were measured by a
ceilometer and Doppler wind radar, respectively, and the characteristics of
the atmospheric dilution capability were analyzed using these two datasets.
The ventilation coefficient (VC) appears to be the highest in the spring (3940±2110 m2 s−1) and lower in the summer (2953±1322 m2 s−1), autumn (2580±1601 m2 s−1) and winter
(2913±3323 m2 s−1). Combined with the backscatter
measured by the ceilometer, vertical profiles of the PM2.5
concentration were obtained and the PM2.5 TF in the mixing layer was
calculated. The TF was the highest in the spring at 4.33±0.69 mg m−1 s−1 and lower in the summer, autumn and winter, when the TF
values were 2.27±0.42, 2.39±0.45 and 2.89±0.49 mg m−1 s−1, respectively.
Air pollutants transport mainly occurs between 14:00 and 18:00 LT. The TF
was large in the pollution transition period (spring: 5.50±4.83 mg m−1 s−1; summer: 3.94±2.36 mg m−1 s−1; autumn:
3.72±2.86 mg m−1 s−1; winter: 4.45±4.40 mg m−1 s−1) and decreased during the heavy pollution period (spring:
4.69±4.84 mg m−1 s−1; summer: 3.39±1.77 mg m−1 s−1; autumn: 3.01±2.40 mg m−1 s−1; winter:
3.25±2.77 mg m−1 s−1). Our results indicate that the
influence of the air pollutants transport in the southern regions should
receive more focus in the transition period of pollution, while local
emissions should receive more focus in the heavy pollution period.
Effective densities of soot particles and their relationships with the mixing state at an urban site of the Beijing mega-city in the winter of 2018
Authors: Liu Hang , Pan Xiaole , Wu Yu , Wang Dawei , Tian Yu , Liu Xiaoyong , Lei Lu , Sun Yele , Fu Pingqing , Wang Zifa
Published: July 2019

Abstract. The effective density (ρeff) of refractory black carbon (rBC) is a key parameter relevant to their mixing state that imposes great uncertainty when evaluating the direct radiation forcing effect. In this study, a novel tandem DMA-CPMA-SP2 system was used to investigate the relationship between the effective density (ρeff) and the mixing state of rBC particles during the winter of 2018 in the Beijing mega-city. During the experiment, aerosols with a known mobility diameter (Dmob) and known ρeff values (0.8, 1.0, 1.2, 1.4, 1.6, and 1.8 g/cm3) were selected and measured by the SP2 to obtain their corresponding mixing states. The results showed that the ρeff well represented the morphological variation in rBC-containing particles. The rBC-containing particles changed from an irregular and loose structure to a compact spherical structure with the increase in ρeff. A ρeff value of 1.4 g/cm3 was the morphological transition point. The morphology and ρeff value of the rBC-containing particles were intrinsically related to the mass ratio of non-refractory matter to rBC (MR). As the ρeff values of the rBC-containing particles increased from 0.8 to 1.8 g/cm3, the MR of the rBC-containing particles significantly increased from 2 up to 6–8, indicating that atmospheric aging processes were likely to lead to the reconstruction of more compact and regular particle shapes. During the observation period, the ρeff of most rBC-containing particles was lower than the morphology transition point independent of the pollution conditions, suggesting that the major rBC-containing particles did not have a spherical structure. Simulation based on an aggregate model considering the morphological information of the particles demonstrated that absorption enhancement of rBC-containing particles could be overestimated by ~ 17 % by using a core-shell model. This study highlights the strong dependence of the morphology of ambient rBC-containing particles on ρeff and will be helpful for elucidating the micro physical characteristics of rBC and reducing uncertainty in the evaluation of rBC climate effects and health risks.
Tropopause altitude determination from temperature profile measurements of reduced vertical resolution
Authors: König Nils , Braesicke Peter , von Clarmann Thomas
Published: July 2019

Abstract. Inference of the lapse rate tropopause or the cold point from temperature
profiles of finite vertical resolution entails an uncertainty of the
tropopause altitude. For tropical radiosonde profiles the tropopause altitude
inferred from coarse-grid profiles was found to be lower than that inferred
from the original profiles. The mean (median) displacements of the lapse rate
tropopause altitude when inferred from a temperature profile of 3 km vertical
resolution and a Gaussian kernel are −130, −400, −730, and −590 m
(−70, −230, −390, and −280 m) for Nairobi, Hilo, Munich, and Greifswald,
respectively. In the case of a Michelson Interferometer for Passive Atmospheric
Sounding (MIPAS) averaging kernel, the displacement of the lapse
rate tropopause altitude is −640 m. The mean (median) displacement of the
cold point tropopause inferred from a temperature profile of 3 km vertical
resolution (Gaussian kernels) was found to be −510, −610, −530, and
−390 m (−460, −510, −370, and −280 m) for the stations mentioned above.
Unsurprisingly, the tropopause altitude displacement is larger for coarser
resolutions. The effect of the tropopause displacement on the water vapor
saturation mixing ratio is roughly proportional to the vertical resolution.
In tropical latitudes the resulting error is about 1 to 2 ppmv per vertical resolution in kilometers. The spread of the tropopause
displacements within each sample of profiles seems too large as to recommend
a correction
scheme for tropical temperature profiles, while for midlatitudinal temperature
profiles of vertical resolutions of 1 to 5 km a lapse rate of −1.3 K km−1
reproduces tropopause altitudes determined from high-resolution temperature
profiles with the nominal lapse rate criterion of −2 K km−1 fairly well.
Towards an understanding of surface effects: Testing of various materials in a small volume measurement chamber and its relevance for atmospheric trace gas analysis
Authors: Satar Ece , Nyfeler Peter , Pascale Céline , Niederhauser Bernhard , Leuenberger Markus
Published: July 2019

Abstract. A critical issue for the long-term monitoring of atmospheric trace gases is precision and accuracy of the measurement systems employed. To ensure the best preparation and measurement conditions for trace gases in very low amount fractions, usage of coated materials is in demand in gas metrology and atmospheric measurement communities. This study focuses on the testing of different materials or coatings that are currently used, or may be relevant in future for the measurements of greenhouse gases. For this study, we used the previously tested small volume cylinders, which were constructed such that they can serve as adsorption test chambers. Various materials with or without coatings were loaded into the small cylinder to test their adsorption/desorption behavior. We used the aluminum cylinder as the measurement chamber, and glass, aluminum, copper, brass, steel and three different commercially available coatings as test materials. Inserting the test materials into the measurement chamber doubles the available geometric area for the surface processes. The presented experiments were designed to investigate the pressure dependency up to 15 bar, and temperature dependency up to 80 °C for the test materials placed in the measurement chamber. Here, we focused on the species CO2, CH4, CO and H2O measured by a cavity ring down spectroscopy analyzer. Our results show that the materials currently used in atmospheric measurements are well-suited. The investigated coatings were not superior to untreated aluminum or to stainless steel at the tested pressure ranges, whereas under changing temperature aluminum showed better performance for CO2 (< 0.05 μmol mol−1 change in measured amount fractions) than stainless steel (> 0.1 μmol mol−1). To our knowledge, this study is one of the first attempts to investigate surface effects of different materials in such a setup for the above-mentioned gases.
Automatic Quality Control of the Meteosat First Generation Measurements
Authors: Liefhebber Freek , Lammens Sarah , Brussee Paul , Bos André , John Viju O. , Rüthrich Frank , Onderwaater Jacobus , Grant Michael G. , Schulz Jörg
Published: July 2019

Abstract. Now that the Earth has been monitored by satellites for more than 40 years, Earth Observation images can be used to study how the Earth system behaves over extended periods. Such long-term studies require the combination of data from multiple instruments, with the earliest data sets being of particular importance in establishing a baseline for trend analysis. As the quality of these earlier datasets is often lower, careful quality control is essential, but the sheer size of these image sets makes an inspection by hand impracticable. Therefore, one needs to resort to automatic methods to inspect these Earth Observation images for anomalies. In this paper, we describe the design of a system that performs an automatic anomaly analysis on Earth Observation images, in particular the Meteosat first generation measurements. The design of this system is based on a preliminary analysis of the typical anomalies that can be found in the data set. This preliminary analysis was conducted by hand on a representative subset and resulted in a finite list of anomalies that needed to be detected in the whole data set. The automated anomaly detection system employs a dedicated detection algorithm for each of these anomalies. The result is a system with a high probability of detection and low false alarm rate. Furthermore, most of these algorithms are able to pinpoint the anomalies to the specific pixels affected in the image, allowing the maximum use of the data available.
Regulation of carbon dioxide and methane in small agricultural reservoirs: Optimizing potential for greenhouse gas uptake
Authors: Webb Jackie R. , Leavitt Peter R. , Simpson Gavin L. , Baulch Helen , Haig Heather A. , Hodder Kyle R. , Finlay Kerri
Published: July 2019

Abstract. Small farm reservoirs are abundant in many agricultural regions across the globe and have the potential to be large contributing sources of carbon dioxide (CO2) and methane (CH4) to agricultural landscapes. Compared to natural ponds, these artificial waterbodies remain overlooked in both agricultural greenhouse gas (GHG) inventories and inland water global carbon (C) budgets. Improved understanding of the environmental controls of C emissions from farm reservoirs is required to address and manage their potential importance. Here, we conducted a regional scale survey (~ 235,000 km2) to measure CO2 and CH4 concentrations and diffusive fluxes across 101 small farm reservoirs in Canada's largest agricultural area. A combination of abiotic, biotic, hydromorphologic, and landscape variables were modelled using generalized additive models (GAMs) to identify regulatory mechanisms. We found that CO2 concentration was best estimated by a combination of internal metabolism and groundwater-derived alkalinity (65.7 % deviance explained), while multiple lines of evidence support a positive association between eutrophication and CH4 production (74.1 % deviance explained). Fluxes ranged from −21 to 466 and 0.14 to 92 mmol m−2 d−1 for CO2 and CH4, respectively, with CH4 contributing an average of 74% of CO2-equivalent (CO2-e) emissions. Approximately 19 % farm reservoirs were found to be net CO2-e sinks. From our models, we show that the GHG impact of farm reservoirs can be greatly minimised through overall improvements in water quality and the construction and maintenance of deeper reservoirs.
The INALT family – a set of high-resolution nests for the Agulhas Current system within global NEMO ocean/sea-ice configurations
Authors: Schwarzkopf Franziska U. , Biastoch Arne , Böning Claus W. , Chanut Jérôme , Durgadoo Jonathan V. , Getzlaff Klaus , Harlaß Jan , Rieck Jan K. , Roth Christina , Scheinert Markus M. , Schubert René
Published: July 2019

Abstract. The Agulhas Current, the western boundary current of the South Indian Ocean, has been shown to play an important role in the connectivity between the Indian and Atlantic oceans. The greater Agulhas Current system is highly dominated by mesoscale dynamics. To investigate their influence on the regional and global circulations, a family of high-resolution ocean general circulation model configurations based on the NEMO code has been developed. Horizontal resolution refinement is achieved by embedding “nests” covering the South Atlantic and the western Indian oceans at 1/10∘ (INALT10) and 1/20∘ (INALT20) within global hosts with coarser resolutions. Nests and hosts are connected through two-way interaction, allowing the nests not only to receive boundary conditions from their respective host but also to feed back the impact of regional dynamics onto the global ocean. A double-nested configuration at 1/60∘ resolution (INALT60) has been developed to gain insights into submesoscale processes within the Agulhas Current system.
Large-scale measures such as the Drake Passage transport and the strength of the Atlantic meridional overturning circulation are rather robust among the different configurations, indicating the important role of the hosts in providing a consistent embedment of the regionally refined grids into the global circulation.
The dynamics of the Agulhas Current system strongly depend on the representation of mesoscale processes. Both the southward-flowing Agulhas Current and the northward-flowing Agulhas Undercurrent increase in strength with increasing resolution towards more realistic values, which suggests the importance of improving mesoscale dynamics as well as bathymetric slopes along this narrow western boundary current regime.
The exploration of numerical choices such as lateral boundary conditions and details of the implementation of surface wind stress forcing demonstrates the range of solutions within any given configuration.
Correcting a bias in a climate model with an augmented emulator
Authors: McNeall Doug , Williams Jonny , Betts Richard , Booth Ben , Challenor Peter , Good Peter , Wiltshire Andy
Published: July 2019

Abstract. A key challenge in developing flagship climate model configurations is the process of setting uncertain input parameters at values that lead to credible climate simulations. Setting these parameters traditionally relies heavily on insights from those involved in parameterisation of the underlying climate processes. Given the many degrees of freedom and computational expense involved in evaluating such a selection, this can be imperfect leaving open questions about whether any subsequent simulated biases result from mis-set parameters or wider structural model errors (such as missing or partially parameterised processes). Here we present a complementary approach to identifying plausible climate model parameters, with a method of bias correcting subcomponents of a climate model using a Gaussian process emulator that allows credible values of model input parameters to be found even in the presence of a significant model bias. A previous study (McNeall et al., 2016) found that a climate model had to be run using land surface input parameter values from very different, almost non-overlapping parts of parameter space to satisfactorily simulate the Amazon and other forests respectively. As the forest fraction of modelled non-Amazon forests was broadly correct at the default parameter settings and the Amazon too low, that study suggested that the problem most likely lay in the model's treatment of non-plant processes in the Amazon region. This might be due to (1) modelling errors such as missing deep-rooting in the Amazon in the land surface component of the climate model, (2) a warm-dry bias in the Amazon climate of the model, or a combination of both. In this study we bias correct the climate of the Amazon in a climate model using an augmented Gaussian process emulator, where temperature and precipitation, variables usually regarded as model outputs, are treated as model inputs alongside regular land surface input parameters. A sensitivity analysis finds that the forest fraction is nearly as sensitive to climate variables as changes in its land surface parameter values. Bias correcting the climate in the Amazon region using the emulator corrects the forest fraction to tolerable levels in the Amazon at many candidates for land surface input parameter values, including the default ones, and increases the valid input space shared with the other forests. We need not invoke a structural model error in the land surface model, beyond having too dry and hot a climate in the Amazon region. The augmented emulator allows bias correction of an ensemble of climate model runs and reduces the risk of choosing poor parameter values because of an error in a subcomponent of the model. We discuss the potential of the augmented emulator to act as a translational layer between model subcomponents, simplifying the process of model tuning when there are compensating errors, and helping model developers discover and prioritise model errors to target.
Application of logistic regression to simulate the influence of rainfall
genesis on storm overflow operation: a probabilistic approach
Authors: Szeląg Bartosz , Suligowski Roman , Studziński Jan , De Paola Francesco
Published: July 2019

Abstract. One of the key parameters constituting the basis for the assessment of the operation of stormwater systems is the annual number of storm overflows. Since uncontrolled overflow discharges are a source of pollution washed away from the surface of the catchment area, which leads to an imbalance in the receivers, there is a need for their prognosis and potential reduction. This paper proposes an innovative probabilistic model to simulate the number of storm overflow discharges, which takes into account atmospheric circulation and related rainfall in the research area (the city of Kielce located in the central part of Poland). The developed model consists of two independent elements. The first element is the model of logistic regression, which can be used to model storm overflow discharge resulting from the occurrence of a single rainfall episode. The paper confirmed that storm overflow discharge can be modeled on the basis of data on the total amount of rainfall and its duration. An alternative approach was also proposed, in which the possibility of forecasting overflow discharge only on the basis of the average rainfall intensity was demonstrated, which is a big simplification in simulation of the phenomenon under study in comparison with the works published so far in this scope. It is worth noting that the coefficients determined in logit models have a physical interpretation and these models have a universal character, which is why they can be easily adapted to other examined catchment areas. The second element of the model is a synthetic precipitation generator, in which the simulation of rainfall takes into account its genesis resulting from various processes and phenomena taking place in the troposphere. This approach makes it possible to take into account the stochastic nature of rainfall also in relation to the annual number of events. Calculations made in the paper on the example of the examined catchment allowed to assess the influence of rainfall characteristics (depth, intensity, duration) of different genesis on the probability of storm overflow discharge. On the basis of the obtained results, the range of variability of average rainfall intensity was determined, which determines the discharge by storm overflow, as well as the annual number of discharges resulting from the occurrence of rain of different genesis. The obtained results enable their practical implementation in the assessment of storm overflows only on the basis of knowledge concerning the genetic type of rainfall. They can be used to develop warning systems, in which information on the predicted rainfall genesis is a component of the assessment of the operation of the stormwater system and the facilities located on it.
RICE AREA ESTIMATION USING PARAMETERIZED CLASSIFICATION OF SENTINEL 1A SAR DATA
Authors: Raman M. G. , Kaliaperumal R. , Pazhanivelan S. , Kannan B.
Published: July 2019

Abstract. A research study was conducted during Rabi 2016 (Samba season) to estimate rice area using SAR data in Tiruvarur district of Tamil Nadu. Multi temporal Sentinel 1A satellite data with VV and VH polarization at 20 m spatial resolution was acquired between September 2016 and January 2017 at 12 days interval and processed using rule-based Parameterized classification in MAPscape-RICE software. Continuous monitoring for crop parameters and validation exercise was done for accuracy assessment. Spectral dB curve of rice was generated and the dB values ranged from −12.76 to −9.95 for VV and from −19.25 to −15.15 for VH polarization with an average primary variation of 1.3 and 2.5 dB respectively. Start of Season (SOS) map was derived from satellite data showing rice emergence dates for the cropping season. A total rice area of 106773 ha was estimated in Tiruvarur district using VV polarization with an overall accuracy of 79.5% and 0.59 kappa index, while in VH polarization, the rice area was estimated to be 91007 ha with 82.1% over all accuracy and 0.64 kappa index. The lesser accuracy in VV polarization was due to underestimate of direct seeded rice area and in VH polarization, it was due to underestimate in Transplanted rice area. The VV and VH rice area maps were then integrated to derive a VV-VH rice area map in MAPscape-RICE software and it recorded a total rice area of 124551 ha with an accuracy of 91.5% and 0.83-kappa index.
UNDERSTANDING THE DYNAMIC OF TROPICAL AGRICULTURE FOR REMOTE SENSING APPLICATIONS: A CASE STUDY OF SOUTHEASTERN BRAZIL
Authors: Sanches I. D. , Luiz A. J. B. , Montibeller B. , Schultz B. , Trabaquini K. , Eberhardt I. D. R. , Formaggio A. R. , Maurano L. E.
Published: July 2019

Abstract. The agricultural activity can greatly benefit from remote sensing technology (RS). Optical passive RS has been vastly explored for agricultural mapping and monitoring, in despite of cloud cover issue. This is observed even in the tropics, where frequency of clouds is very high. However, more studies are needed to better understand the high dynamism of tropical agriculture and its impact on the use of passive RS. In tropical countries, such as in Brazil, the use of current agricultural technologies, associated with favourable climate, allow the planting period to be wide and to have plants of varying phenological cycles. In this context, the main objective of the current study is to better understand the dynamics of a selected area in Southeast of São Paulo state, and its impact on the use of orbital passive RS. For that purpose, data (from field and satellite) from 55 agricultural fields, including annual, semi-perennial and perennial crops and silviculture, were acquired between July 2014 and December 2016. Field campaigns were conducted in a monthly base to gather information about the condition of the crops along their development (data available in a website). Field data corresponding to the 2014–2015 crop year were associated with a time series of Landsat-8/OLI RGB false-colour compositions images and MODIS/Terra NDVI profiles. The type of information that can be extracted (such as specie identification, crop management practices adopted, date of harvest, type o production system used etc) by combining passive remote sensing data with field data is discussed in the paper.
GIS BASED ANALYSIS OF SPATIAL DISTRIBUTION OF NDVI FOR AGRICULTURAL APPLICATIONS IN SALEM DISTRICT – TAMIL NADU
Authors: Venkadesh S. , Jagannathan R. , Ragunath K. P.
Published: July 2019

Abstract. Remote sensing satellites in recent years have emerged as a vital tool for generating the biophysical information, which further helps to evolve the optimal land use plan for sustainable development of an area. The natural resources are to be categorized to obtain the area best suitable for crop production so that they could be better utilized in agricultural planning. The Normalized Difference Vegetation Index (NDVI) has been widely used to monitor moisture-related vegetation condition. The 8-day composite and spatial resolution of 250 m for the years 2002–2012 have obtained from the Moderate Resolution Imaging Spectro-radiometer (MODIS) Surface Reflectance (MOD09A) used for grouping biomass. The MOD09A product was selected because it consisted of both visible and infrared bands, which is requisite for deriving NDVI. The NDVI was used to determine the biomass categorization had four classes B1 (NDVI of 0.06–0.10), B2 (0.1 to 0.2), B3 (0.2–0.4) and B4 (> 0.4) which were rated as poor, moderate, good and excellent, respectively. Here, excellent biomass category was found to cover more area compared to other biomass categories. The per cent area covered under excellent category was (88.7 %) in Salem district. This showed that the agriculture area in this district is largely suitable for crop growth. The categorization of biomass as good to excellent in Salem might be due to the good seasonal (both monsoon) rainfall. It could pave way for better agricultural management and transfer of technology.
SPATIO-TEMPORAL STUDY OF BRAHMAPUTRA RIVER ISLANDS (CHARS) FOR AGRICULTURE EXPANSION IN ASSAM, INDIA
Authors: Prashnani M. , Qadir A. , Goswami J. , Raju P. L. N.
Published: July 2019

Abstract. The present paper aims to understand the spatio-temporal dynamics of the Brahmaputra river islands locally known as chars in Assam for agriculture crop expansion using long term multispectral satellite data and Google Earth Engine. This study also provides information on existing agriculture lands on these chars. For the study Landsat data is analysed to find the long term stable islands (1988–2018) and the present status of these islands for seasonal crop expansion. Validation of results was performed by using high-resolution satellite data. It is found that total area of vegetative chars has increased in past three decades and approximately 146 thousand hectares area of char is stable from past ten years. This study also reveals that the major crop cultivation is in Lower Brahmaputra Valley (LBV). In Upper Brahmaputra Valley (UBV), the crop cultivation is almost negligible compared to the large islands size. It can be inferred that less stable chars which are mostly located in upper Assam has negligible agriculture. It is also observed that at many places in lower Assam, double cropping system is followed. This study can be further extended by including factors like soil type, soil texture, rainfall, socio-economic etc. to study suitability for different crops. Proper facilities and incentives are to be provided to farmers of this region for better food security.
RAPID IDENTIFICATION OF ABIOTIC STRESS (FROST) IN IN-FILED MAIZE CROP USING UAV REMOTE SENSING
Authors: Goswami J. , Sharma V. , Chaudhury B. U. , Raju P. L. N.
Published: July 2019

Abstract. Stress in the crop not only decreases the production but can also have devastating consequences for farmers whose life depends upon the healthy crops. In recent time (January 2018) a such abiotic stress event (hoar frost) was experienced at ICAR research complex experimental filed, Ri-Bhoi district of Meghalaya on standing Maize crop. Therefore, remote sensing (Multispectral UAV- Unmanned Aerial Vehicle) technology were used to detect the effect of frost on in-filed Maize crop. Two set of multispectral data (before frost and after frost) with four advanced machine learning techniques viz. Random Forest (RF), Random Committee (RC), Support Vector Machine (SVM) and Artificial Neural Network were employed for detection of stress free crop and stressed crop due to frost. Results revealed that all the four methods of classification could able to identify / detect stress-free vs. stressed crops at satisfactory level. However, among the classifiers RF achieved relatively higher overall accuracy (OA = 86.47%) with Kappa Indexanalysis (KIA = 0.80) and found very cost effective in context of computational cost (time complexity = 0.08 Seconds) to train the model. In addition, we have also recorded the area of each classes and found that after frost stress-free area (36.01% of all over filed) is decreased by 11% in comparison of before frost (25.036% of all over filed). Based on the results we can suggest that the RF ensemble classification method can be used for further other crop classification in order to estimate the yield, detect the condition, monitoring the health etc.
CROP DAMAGE ASSESSMENT IN FLOOD INUNDATED AREA OF MORIGAON DISTRICT OF ASSAM
Authors: Rasid N. , Prashnani M. , Goswami J. , Raju P. L. N.
Published: July 2019

Abstract. Cropping System Analysis is essential for studying the sustainability of Agriculture. Remote sensing technology provide continuous and synoptic observations of crop area over large extent and substantial contribution in monitoring, evaluating and forecasting of crop and its damage assessment both in cloud and cloud-free environment. Geo-stationary satellites like Synthetic Aperture Radar (SAR) can penetrate through clouds hence it help in assessment of crop even in hazy atmospheric circumstances like fog, smog, light rain, mist etc. The present study reviews cropping pattern and crop rotation of of Morigaon District of Assam. Landsat OLI- 8 multi-spectral data , sentinel 2 multi-spectral and sentinel- 1 SAR data was collected during crop year 2015, 2016 and 2017. The microwave SAR data was used for the classification of crop area for Kharif season due to unavailability of optical cloud free data and also helps in estimation of flood water propagation and its extent and its significant loss to agriculture crop. The result of the pilot study shows that integration of SAR data and GIS environment can be exploited in an efficient way to assess the crop damage area due to flood. Block-wise flood inundation statistics have been derived. This study can be extended to other states/ districts as data collected by satellite can be standardized, the data are reliably objective.