Exploring the spatial distribution patterns of South African Cape hakes using generalised additive models

We developed delta generalised additive models (GAMs) to predict the spatial distribution of different size classes of South African hakes, Merluccius capensis and M. paradoxus, using demersal trawl survey data and geographical (latitude and longitude) and environmental features (depth, temperature, bottom dissolved oxygen and sediment type). Our approach consists of fitting, for each hake size class, two independent models, a binomial GAM and a quasi-Poisson GAM, whose predictions are then combined using the delta method. Delta GAMs were validated using an iterative cross-validation procedure, and their predictions were then employed to produce distribution maps for the southern Benguela. Delta GAM predictions confirmed existing knowledge about the spatial distribution patterns of South African hakes, and brought new insights into the factors influencing the presence/absence and abundance of these species. Our GAM approach can be used to produce distribution maps for spatially explicit ecosystem models of the southern Benguela in a rigorous and objective way. Ecosystem models are critical features of the ecosystem approach to fisheries, and distribution maps constructed using our GAM approach will enable a reliable allocation of species biomasses in spatially explicit ecosystem models, which will increase trust in the spatial overlaps and, therefore, the trophic interactions predicted by these models.     

Accuracy assessment of noise mapping on the main street

Among the sounds constituting a part of our daily lives, the undesired and disturbing ones are named noise. The noises can be defined as the acoustic energy that affects the physiological and psychological welfare of humans due to its direct or indirect effects on the human health. But, the traffic noise, which is one of the disturbing noises having wide dispersion in urban areas, affects the health of a gradually increasing number of people. The number of studies on measurement, dispersion, and mapping of traffic noise in developed and developing countries is gradually increasing. It can be seen that the studies concentrate on mapping based on the city centers and neighborhoods, where the traffic is intense. In this article, unlike the regional noise measurement studies, the transversal cross sections were established with a certain interval according to the land status along the main street, and the noise measurement points were determined using the global navigation satellite system (GNSS). The daily mean noise levels (L_den) were calculated by performing the measurements at daytime, evening, and nighttime. Using ArcGIS 10.4 software, the accuracy of noise maps created via inverse distance weighting (IDW), radial basis function (RBF), and ordinary kriging (OK) geostatistical analysis interpolation methods and the dispersion effect of traffic noise were compared. According to the visual method and error corrections, it was found that the best noise map was obtained using the RBF method. It is believed that the map provides accurate and reliable results because of the flat land surface, higher noise values measured on the road region, decrease in the noise at the points farther from the road region, and soft transitions between the noise values depending on the distance from the road. In order to take measures in order to decrease or eliminate noise on the main street, the local administrators and decision-makers can make use of these maps, the accuracy of which has been confirmed.     

The measurement of soil gases and shallow temperature for determination of active faults in a geothermal area: a case study from Ömer–Gecek,Afyonkarahisar (West Anatolia)

Afyonkarahisar is a very important geothermal province of western Anatolia and has low and medium enthalpy geothermal areas. This study has been carried out for the preparation of distribution maps of soil gases (radon and carbon dioxide) and shallow soil temperature and the exploration of permeable tectonic regions associated with geothermal systems and reveal the origins of radon and carbon dioxide gases. The western district of the study area is characterized by the high radon concentration (168.30 kBq/m³), carbon dioxide ratio (0.30%), and soil temperature (21.0 °C) values. Fethibey and Demirçevre faults, which allow the circulation of geothermal fluids, have been detected in the distribution maps of radon, carbon dioxide, and shallow depth temperature and the directions of the curves in these maps correspond to the strikes of Demirçevre faults. The effect of the fault plays an important role in the change of carbon dioxide concentration along the W-E directional geological section prepared to determine the change of soil gas and shallow depth temperature values depending on lithological differences, fault existence, and geothermal reservoir depth. On the other hand, it was determined that Rn²²² concentration and soil temperature changed as a function of geothermal reservoir depth or lithological difference. Tuffs in Köprülü volcano-sedimentary units are the main source of radon due to their higher uranium contents. Besides, the carbon dioxide in Ömer–Gecek soils has geothermal origin because of the highest carbon dioxide content (99.3%) in non-condense gas. The similarities in patterns of soil temperature, radon, and carbon dioxide indicate that the variation in soil temperatures is related to radon and carbon dioxide emissions. It is concluded that soil gas and temperature measurements can be used to determine the active faults in the initial stage of geothermal exploration successfully.     

Image-aided platform orientation determination with a GNSS/low-cost IMU system using robust-adaptive Kalman filter

The availability of miniaturized sensors with enhanced capabilities, new methods for image processing, and easy access to small and low-weight airborne platforms for data acquisition, including unmanned vehicles, opens new possibilities for geodetic navigation applications and developing new developments in sensor fusion. In this context, the development of efficient methods, based on low-cost sensors, to extract precise georeferenced information from digital cameras is of utmost interest. We present a method to improve the performance of the integration of GNSS/low-cost IMU by exploiting the orientation changes retrieved from digital images. In this work, a robust-adaptive Kalman filter is also introduced to further improve the performance of the method deployed. The adaptive factor and the robust factor accomplished are determined by innovation information and the threshold value of orientation changes between consecutive images. Results from airborne tests used to assess the performance of the method are presented. The results show that using a non-metric camera, the Euler angle estimation accuracy of the GNSS/low-cost IMU integration can be improved to be close to 0.5 degree and an additional improvement, which can reach 59%, can be achieved after using the robust-adaptive Kalman filter.     

‘Filament’ marker beds in the Karababa-A Member (Turonian) of the Arabian platform,SE Turkey: Palaeo-environmental significance,stratigraphy and correlation potential

A ‘filament’ event bed/level corresponds to the occurrence of thin elongate calcitic, shells, or plates of pelagic, bivalve or crinoidal, origin, within pelagic, laminated and organic-matter rich limestones. These organic-rich limestones had been generally deposited under hypoxic/anoxic conditions in an outer-ramp environment. These thin elongate, bivalve shells, or crinoidal plates, are found broken in small pieces, disintegrated, or simply preserved parallel to bedding as almost complete specimens. Such ‘filament’ beds were spotted in SE Turkey in deposits, namely the Karababa-A Member, around the Cenomanian-Turonian boundary (C/TB) and above. On a global scale, these filament event beds illustrate sea-level rise related to eustacy and/or climatic change. The abundance of filaments close to the C/TB is a biological marker of high organic productivity resulting from a climatic change to warmer conditions. The prevailing higher sea-level conditions were then favourable to the accumulation and preservation of organic-rich facies, characteristic of the Oceanic Anoxic Event 2 (OAE2). Using both biostratigraphic and carbon isotopic data, those deposits were dated from the latest Cenomanian-Turonian age. ‘Filament’ event beds were recorded in the same order, except for some small differences. A good number of these bio-events are global. Consequently, on a global scale, they are susceptible to constrain the C/TB, especially the base of the Turonian stage, with a significant degree of confidence.     

The investigation of flood risk perception as a quantitative analysis from socio-demographic perspective

The priority of flood management planning is physical victimization and focuses on taking structural measures. Although this approach is an accurate approach, more information is needed in implementing efficient precautionary and planning decisions. It is an indisputable fact that the existence of nothing that is not sustainable in nature cannot continue. Hence, it is necessary to implement a planning decision suitable for the structure of the population living in the region so that the continuity of the policies to be carried out against natural hazards of hydrometeorological origin such as a flood is ensured. How the socio-demographic structures affect the flood risk perception of 245 people living in the city center of Bayburt is examined in this study. It is the first research conducted for the province of Bayburt for this perspective. The participants were asked to fill a questionnaire containing 24 items and consisting of 2 sections. T test and one-way ANOVA (one-way analysis of variance) statistical methods were used to ascertain the difference between the responses of the participants to the questionnaire, based on their demographic structure. As the result of the study, significant differences were observed between the expressions depicting flood risk perception and the participant's age, income levels and educational background. In addition, it has been noted that there is a positive relationship between education and income levels and flood risk perception.

     

Hydrologic models coupled with 2D hydrodynamic model for high-resolution urban flood simulation

Natural Hazards - Floods are the most frequent natural disaster and pose a very challenging threat to many cities worldwide. Understanding the flood dynamic is essential for developing strategies...     

Long- and short-term volcanic hazard assessment of El Chichón Volcano (Mexico) through Bayesian inference

Natural Hazards - The 1982 eruption of El Chichón volcano constitutes the worst volcanic disaster in Mexico producing more than 2000 fatalities, thousands of displaced people and severe...     

Groundwater metering: revisiting a ubiquitous ‘best practice’

Hydrogeology Journal - It is often taken for granted that metering is an unarguable ‘best practice’ when it comes to the quantitative management of groundwater resources. This paper...