Paired Stations Research Articles

Characterization of the geomagnetic H-component for a paired station in Africa

This scientific research investigates the quiet days variation, Sq(H) of H- component of geomagnetic field for the paired stations: Aswan (ASW: G.G.Lat.24.090N, G.G.Lon.32.890E and G.M.Lat.15.200, G.M.Lon.104.240),Durban (DRB: G.G.Lat.29.860S, G.G.Lon.31.020E and G.M.Lat.39.210, G.M.Lon.96.10) located along the 960 MM (magnetic meridian) using the ten international quietest days’ geomagnetic data from MAGDAS for the year 2009 (a low activity year).The study reveals that sq(H) shows predominantly the diurnal, monthly and seasonal variations of the geomagnetic H-component during the quiet days year round. With maximum amplitude of sq(H) in ASW and minimum in DRB. Meanwhile, the CEJ seen as negative depressions in the H-component of earth field at DRB are all salient physical processes in this study. Further data analysis also revealed many other interesting characteristics for the Sq(H) over African sector paired station. The conclusion drawn from the study shows that the geomagnetic field variations in the northern hemisphere are higher due to solar activities in the region. The Northern Hemisphere is tilted toward the sun, so this area of the Earth receives more direct sunlight during the day than the Southern Hemisphere does. The Southern Hemisphere, on the other hand, is tilted away from the sun and thus receives the sun's rays at an angle, which significantly explains why there is a consistent decrease when it reaches the Durban station (southern hemisphere station), hence the solar activity of the sun influences the Earth’s magnetic field, and the upper atmosphere(ionosphere).

Preliminary Result of Rayleigh Wave Tomography beneath Jailolo Volcanic Complex, North Moluccas, Indonesia using Ambient Noise

From November 2015 to February 2016, seismic swarm activity occurred around Jailolo volcano, a long-dormant and few-studied volcano located on Halmahera Island, North Moluccas, Indonesia. We perform seismic ambient noise tomography method to delineate the sub-surface seismic structure beneath Jailolo volcanic complex. We use the vertical seismogram data from 29 temporary short-period seismic stations of 7G Seismic Network from January to March 2017 observation. The 7G Seismic Network was collaborative research between the Indonesian Agency of Meteorology, Climatology, Geophysics (BMKG), Indonesia, and the German Research Centre for Geoscience (GFZ). We cross-correlated vertical components of pair stations to estimate Green’s Rayleigh wave function. More than 350 group velocities were estimated. We measure the dispersion characteristic of Rayleigh wave group velocity by applying the frequency-time analysis (FTAN) technique. We compare Green Function and the dispersion curve by applying different band-pass filters. The Green Function of Rayleigh wave is clearly seen in causal and/or acausal part by applied 0.01-0.5 Hz band-pass filter and then dispersion curve is picked within 2-10 s. The Rayleigh group velocities average is 0.6-0.9 km/s.

Fast Urbanization Causes Overestimation of Global Warming Trends

The contribution of urbanization to the global warming tendency has not been evaluated accurately. We propose that comparing the temperature records of relocated new meteorological stations to those of old meteorological stations is a better method for evaluating the urbanization contribution than the current methods. On the Web of Science and the China National Knowledge Infrastructure, previous studies on temperature records of paired old and relocated new meteorological stations were searched and selected. As a result, we gathered temperature data from 57 paired stations and discovered that the old stations' temperature was 0.66 ℃ higher than the new stations' (-0.90 to 1.63 ℃). The urbanization process may be responsible for more than 60% of the current temperature rise trends. Furthermore, there are strong correlations between periods of global warming and regional rapid urbanization, implying that rapid urbanization causes overestimation of global warming trends. Finally, the IPCC's assessment of global warming should be revised in the next report based on paired urban and rural temperature datasets from globally relocated meteorological stations.

Precipitable water vapor estimated using GPS precise point positioning

Precipitation water vapor is an important indicator of climate change. It is related to the moisture in the atmosphere. Atmospheric water vapor is one of the primary greenhouse gases, and it plays a critical role in weather forecasting, micrometeorology, and global climate change. Due to their high operational costs, sparse station distribution, and lack of all-weather availability, certain conventional methods of measuring water vapor, such as microwave radiometers and radio-sounding balloons, are limited in their application to modern meteorology. The precipitation water vapor values are can be obtained using Global Positioning System signal delays. The objective of this study is to estimate the zenith wet delay using the Global Positioning System precise point positioning method. Water Vapor can be presented by zenith wet delay. To estimate the strength of the relationship between zenith wet delay from GPS data, the computation of correlation with in situ data from meteorology data has been performed. Using two pair stations (Global positioning system and meteorology station): CMLG-Malang and CPAS-Tretes, the correlation coefficients are strong 0.85 and 0.79, respectively. Finally, GPS data measurement can be a complement to obtain the zenith wet delay and water vapor.

Antipredator responses toward cat fur in wild brown rats tested in a semi-natural environment

Abstract Sensitivity to predator-related cues and performance of antipredator behaviors are universal among prey species. Rodents exhibit a diverse suite of antipredator behaviors that have been examined in both field and laboratory studies. However, the results from the laboratory have not always translated to the field. While laboratory studies consistently indicate strong fear-inducing effects of cat fur/skin odors, it is unclear whether this occurs in the field with wild rats. To address this issue, we tested the antipredator responses of wild brown rats (Rattus norvegicus) to predatory (domestic cat fur) and nonpredatory (common brushtail possum fur) odor cues in a semi-natural experimental paradigm. Rats were housed in open air enclosures containing two feeding stations. Following several nights of acclimatization, the feeding stations were paired with cat fur, possum fur, or no fur. Rats spent less time at a feeding station that was paired with cat fur. Duration of time spent at feeding stations increased across consecutive test days and across hours within individual test nights, although the rate of increase within nights was lower for cat fur paired stations. This overall increase might reflect habituation of antipredator behaviors, increasing hunger, or loss of cue potency over time. We suggest that wild brown rats recognize and respond to cat fur odor cues, but their behavioral response is highly adaptable and finely tuned to the trade-off between predation risk and starvation that occurs across short temporal scales.

Olfactory lures in predator control do not increase predation risk to birds in areas of conservation concern

Abstract Context Lethal control of predators is often undertaken to protect species of conservation concern. Traps are frequently baited to increase capture efficacy, but baited traps can potentially increase predation risk by attracting predators to protected areas. This is especially important if targeted predators can escape capture due to low trap success. Snake traps using live mouse lures may be beneficial if traps effectively remove snakes in the presence of birds and do not attract additional snakes to the area. Aims The present study evaluated whether mouse-lure traps in areas occupied by birds (simulated by deploying bird-lure traps) could influence predation risk from an invasive snake on Guam. Methods Snake traps were used, with Japanese quail (Coturnix japonica) as a proxy for predation risk, to assess if an adjacent trap with a mouse (Mus musculus) would attract brown treesnakes (Boiga irregularis) to a focal area and increase contact between an invasive snake and avian prey. Catch per unit effort (CPUE) at stations containing either a bird-lure trap, mouse-lure trap or pair of traps (i.e. one bird-lure and one mouse-lure trap) was evaluated. Key results Bird-lure traps paired with mouse-lure traps did not differ in CPUE from isolated bird-lure traps. At paired stations, CPUE of snakes in mouse-lure traps was 2.3× higher than bird-lure traps, suggesting mouse lures were capable of drawing snakes away from avian prey. Bird-lure traps at paired stations experienced a decay in captures over time, whereas CPUE for isolated bird-lure traps increased after 9 weeks and exceeded mouse-lure traps after 7 weeks. Conclusions Mouse lures did not increase the risk of snakes being captured in bird-lure traps. Instead, mouse-lure traps may have locally suppressed snakes, whereas stations without mouse-lure traps still had snakes in the focal area, putting avian prey at greater risk. However, snakes caught with bird lures tended to be larger and in better body condition, suggesting preference for avian prey over mammalian prey in larger snakes. Implications Strategic placement of olfactory traps within areas of conservation concern may be beneficial for protecting birds of conservation concern from an invasive snake predator.

Spatial gradients of geomagnetic temporal variations causing the instability of inter-station transfer functions

Spatial gradients in the primary geomagnetic fields directly contribute to both the amplitudes and phases of inter-station transfer functions (IS-TFs). This suggests that, for the analysis of subsurface resistivity structures, IS-TFs should be carefully treated by checking the establishment of the plane-wave assumption. Geomagnetic time-series data include various and complicated characteristics and accordingly, time–frequency domain analysis is suitable for the discussion of spatial gradients of time-varying geomagnetic fields. However, such evaluations are complicated by the huge amount of information contained in the spectrograms from several stations. Therefore, we propose a Multi-Channel Nonnegative Matrix Factorization (MC-NMF) method that can decompose raw spectrograms into several components, allowing the spatial gradient of each geomagnetic temporal variation to be identified. We confirm that such components actually affect the estimation of IS-TFs using data acquired at the Kakioka and Memambetsu magnetic observatories in Japan. We derive the year-to-year changes in IS-TFs from each set of paired stations among Kakioka, Kanoya, and Memambetsu observatories. Although the IS-TFs should exhibit opposite polarities (a negative correlation) when the input and output observatories are swapped; surprisingly, some of them have “identical” polarities. The application of MC-NMF shows that the analyzed geomagnetic data include several components that have various spatial gradients. Although IS-TFs sometimes fail to give the expected implication regarding the spatial gradients of geomagnetic temporal variations, MC-NMF can verify whether the IS-TFs exhibit any spatial gradients. Thus, the use of IS-TFs with MC-NMF can yield better implications regarding subsurface resistivity information.

Historic and contemporary anthropogenic effects on granulometry and species composition detected from sediment cores and death assemblages, Nelson Bays, Aotearoa-New Zealand

To effectively manage anthropogenic stressors causing widespread and pervasive habitat change, resource managers and policy makers require advice on priority stressors to optimally target conservation and restoration outcomes. This is difficult in soft sediment ecosystems affected by multiple stressors operating across centuries with possible legacy interactions. Using tools from the emerging discipline of conservation paleobiology, we attempted to disentangle the effects of two stressors: i) changes to sediments (sedimentation rate, composition) and ii) fishing disturbance across pre-human to contemporary timescales by analysing death assemblages (DA) at a rare location protected from power fishing methods for ca. 30 yr in Nelson Bays, Aotearoa-New Zealand. Replicate sediment cores and surface grab samples were collected at paired stations, spread across three depth profiles (25, 30, 35 m), split inside and outside the fishing exclusion zone. Sediment core geochronologies were established using radioisotope dating and analysis of terrestrial plant palynomorphs (spores, pollen, starch) associated with Māori and European introduction to Aotearoa-New Zealand. Results unearthed a complex of brachiopods, molluscs, crustacea, bryozoan, and Māori-introduced pollen and starch remains – the latter a marine first. Following human arrival in the region (ca.1500AD) statistical models revealed separation of DAs between time periods were correlated with a 10–15% increase in sediment silt content following a ca.11-fold increase in Sediment Accumulation Rates (SAR). In contrast, separation of recent surface DAs (ca. 60yr) are now more strongly correlated with sediment mixing, detected by discordance in radioisotope profiles, consistent with exposure to homogenising effects of fishing disturbance outside the exclusion zone. We conclude that historic legacy effects, ongoing sedimentation and fishing disturbance have synergistically modified the sediment characteristics from “natural” baseline conditions. Those changes have likely contributed to the collapse and lack of recovery of Nelson Bays shellfish fisheries.

Oviposition in the onion fly Delia antiqua (Diptera: Anthomyiidae) is socially facilitated by visual cues.

Ovipositional decisions in herbivorous insects may be affected by social information from conspecifics. Social facilitation of oviposition has been suggested for the onion fly Delia antiqua. In the current study, we found that D. antiqua oviposition was unequal between paired oviposition stations of equal quality and that more eggs were laid on an oviposition station baited with decoy flies than on the control. The increased oviposition toward the decoys continued over time >8 h. When decoys were placed upside down, the number of eggs laid did not differ between the decoy and control sides of oviposition stations, suggesting that social facilitation of oviposition is mediated by visual cues. Based on these findings, mechanisms of social facilitation of oviposition in D. antiqua were discussed.

Validation of GNSS data about the integrated water vapor in Europe using sun photometers

In the article the comparison of time series of integrated water vapor (IWV) for 2015-2017 at 8 pair stations of GNSS and solar photometers of AERONET network in Europe is carried out. The distance between pairs of stations didn’t exceed 20 km. It is shown that bias and standard deviations of divergences have the seasonal course. In the winter GNSS-photometer bias was from –0.61 to 0.34 mm. In the summer the GNSS overestimates IWV relative to photometers by values from 0.52 to 2.26 mm. The standard deviation is maximal in summer and is from 1.31 to 1.64 mm, in winter it decreases to 0.49-0.86 mm that is 5-6% of IWV.

The relationships between urban-rural temperature difference and vegetation in eight cities of the Great Plains

Interpreting the relationship between urban heat island (UHI) and urban vegetation is a basis for understanding the impacts of underlying surfaces on UHI. The calculation of UHI intensity (UHII) requires observations from paired stations in both urban and rural areas. Due to the limited number of paired meteorological stations, many studies have used remotely sensed land surface temperature, but these time-series land surface temperature data are often heavily affected by cloud cover and other factors. These factors, together with the algorithm for inversion of land surface temperature, lead to accuracy problems in detecting the UHII, especially in cities with weak UHII. Based on meteorological observations from the Oklahoma Mesonet, a world-class network, we quantified the UHII and trends in eight cities of the Great Plains, USA, where data from at least one pair of urban and rural meteorological stations were available. We examined the changes and variability in urban temperature, UHII, vegetation condition (as measured by enhanced vegetation index, EVI), and evapotranspiration (ET). We found that both UHI and urban cold islands (UCI) occurred among the eight cities during 2000–2014 (as measured by impervious surface area). Unlike what is generally considered, UHII in only three cities significantly decreased as EVI and ET increased (p<0.1), indicating that the UHI or UCI cannot be completely explained simply from the perspective of the underlying surface. Increased vegetative cover (signaled by EVI) can increase ET, and thereby effectively mitigate the UHI. Each study station clearly showed that the underlying surface or vegetation affects urban-rural temperature, and that these factors should be considered during analysis of the UHI effect over time.

Near-ground effect of height on pollen exposure

The effect of height on pollen concentration is not well documented and little is known about the near-ground vertical profile of airborne pollen. This is important as most measuring stations are on roofs, but patient exposure is at ground level. Our study used a big data approach to estimate the near-ground vertical profile of pollen concentrations based on a global study of paired stations located at different heights. We analyzed paired sampling stations located at different heights between 1.5 and 50 m above ground level (AGL). This provided pollen data from 59 Hirst-type volumetric traps from 25 different areas, mainly in Europe, but also covering North America and Australia, resulting in about 2,000,000 daily pollen concentrations analyzed. The daily ratio of the amounts of pollen from different heights per location was used, and the values of the lower station were divided by the higher station. The lower station of paired traps recorded more pollen than the higher trap. However, while the effect of height on pollen concentration was clear, it was also limited (average ratio 1.3, range 0.7–2.2). The standard deviation of the pollen ratio was highly variable when the lower station was located close to the ground level (below 10 m AGL). We show that pollen concentrations measured at >10 m are representative for background near-ground levels.

A Comparison of Temperature Data from Automated and Manual Observing Networks in Georgia and Impacts of Siting Characteristics

AbstractThe objectives of this study were to compare average monthly and seasonal maximum and minimum temperatures of the Georgia Automated Environmental Monitoring Network (AEMN) to those of geographically close (i.e., paired) manual observations from U.S. Historical Climatology Network (USHCN) stations and Cooperative Observer Program (COOP) stations for the period 2002–13, and to evaluate the extent to which differences in siting characteristics of paired AEMN–USHCN stations contribute to the temperature differences. Correlations for monthly and seasonal maximum and minimum temperatures of paired AEMN–USHCN and AEMN–COOP stations were high and almost always significant, although the correlations for seasonal minimum temperatures were slightly lower than those of maximum temperatures, especially for summer. Monthly maximum and minimum temperatures and seasonal maximum temperatures of paired AEMN–USHCN and AEMN–COOP stations were significantly different in only a few instances, while seasonal minimum temperatures were more often significantly different, particularly for summer. The stronger relationship between maximum temperatures than minimum temperatures for paired stations is logical given that minimum temperatures typically occur when a shallow, decoupled nocturnal boundary layer is more sensitive to local conditions [e.g., land use/land cover (LULC)]. Stepwise regressions confirmed that a portion of the variance of seasonal minimum temperatures of paired AEMN–USHCN stations was explained by differences in LULC, while the variance in seasonal maximum temperatures was explained better by differences in elevation. Despite the generally close relationships between temperatures of paired stations and a portion of the differences being explained, an abrupt change from manual networks to the AEMN without data adjustments would change the Georgia climate record on monthly and seasonal time scales.

Potential of a low‐cost sensor network to understand the spatial and temporal dynamics of a mountain snow cover

AbstractThe spatial and temporal dynamics of seasonal snow covers play a critical role for many hydrological, ecological, and climatic processes. This paper presents a new, innovative approach to continuously monitor these dynamics using numerous low‐cost, standalone snow monitoring stations (SnoMoS). These stations provide snow and related meteorological data with a high temporal and spatial resolution. Data collected by SnoMoS include: snow depth, surface temperature, air temperature and humidity, total precipitation, global radiation, wind speed, and barometric pressure. A total of 99 sensors were placed over the winters 2010/2011 and 2011/2012 at multiple locations within three 40–180 km2 basins in the Black Forest region of Southern Germany. The locations were chosen to cover a wide range of slopes, elevations, and expositions in a stratified sampling design. Furthermore, “paired stations” located in close proximity to each other, one in the open and one underneath various forest canopies, were set up to investigate the influence of vegetation on snow dynamics. The results showed that considerable differences in snow depth and, therefore, snow water equivalent (SWE) are present within the study area despite its moderate temperatures and medium elevation range (400–1500 m). The relative impact of topographical factors like elevation, aspect, and of different types of forest vegetation were quantified continuously and were found to change considerably over the winter period. The recorded differences in SWE and snow cover duration were large enough that they should be considered in hydrologic and climate models.

Hip Internal Rotation Is Correlated to Radiographic Findings of Cam Femoroacetabular Impingement in Collegiate Football Players

The objective of this study was to determine whether physical examinations (flexion-abduction-external rotation [FABER], impingement, range-of-motion profiles) could be used to detect the bony abnormalities of femoroacetabular impingement (FAI) in an athletic population. We performed a prospective study of 65 male collegiate football players. Both hips were evaluated by 2 orthopaedic surgeons for radiographic signs of FAI. The alpha angle and head-neck offset were measured on frog-leg lateral films. The center-edge angle, acetabular index, crossover sign, and alpha angle were measured on anteroposterior films. Measurements were averaged for both observers. Maximum hip range of motion in flexion (supine) and internal/external rotation (supine, sitting, and prone) was measured with a goniometer. Pain provoked by the impingement and FABER tests was also recorded. Examinations were completed at 2 of 4 stations (2 duplicates), each staffed by 2 clinicians (1 examined and 1 measured). The relation between each range-of-motion and radiographic measure was determined. Data from each station were assessed separately. Only those regressions significant (P < .05) for paired stations were considered clinically significant. The alpha angle and head-neck offset measured on the frog-leg lateral films were significantly correlated (all P < .01) to supine, sitting, and prone internal rotation for all stations. Correlation coefficients ranged from -0.59 to -0.35 for alpha angle and 0.42 to 0.57 for head-neck offset. Although 95% of the hips had at least 1 radiographic sign of FAI, pain was reported in only 8.5% and 2.3% during the impingement and FABER tests, respectively. Internal rotation correlates to radiographic measures of cam FAI in this cohort of collegiate football players. Football players with diminished internal rotation in whom hip pain develops should be evaluated for underlying cam FAI abnormalities. Level IV, therapeutic case series.

The response of meiofauna to human trampling on coral reefs

Coastal environments are trampled by humans worldwide; however, there are few studies that evaluate the effect of trampling on the meiofauna of hard substrates, and none on meiofauna of reef environments. We investigated the effects of trampling due to tourism on the meiofauna of reef formations on the northeastern coast of Brazil. Samples were taken from five paired stations located in two areas on the reef: an area protected since 2004, and an area open to tourist visits. Trampling caused important changes in the meiofaunal assemblage. The densities of the total meiofauna and of the commonest groups were negatively affected in the trampled area. Among the major groups, Polychaeta proved to be very sensitive to this disturbance. The meiofauna groups showed different response patterns to trampling depending on the species of algae trampled. Reductions in animal densities were partly attributed to the loss of turf biomass and associated sand caused by trampling, and partly to the direct effect of people stepping on the animals. Considering the importance of meiofauna in the food web as well as its biodiversity, these results highlight the possible negative effects of human trampling on the ecological and economic “services” that coral reefs provide.

Variation of within-day foraging costs in the striped mouse (Rhabdomys pumilio)

Foraging behavior is influenced by spatial and temporal habitat heterogeniety. Here we report on within-day foraging and perceived risk of predation by the striped mouse (Rhabdomys pumilio) in a grassland savannah with wooded “islands” using giving-up densities (GUD, amount of food left behind in depletable food patches). Higher GUDs correspond to higher forging costs. GUDs were measured six times per day at 2-h intervals from paired stations along fern–grass habitat boundaries at 3 and 6m distances from 10 wooded islands. R. pumilio's GUDs varied significantly over the course of the day with highest GUDs during the afternoon hours of 1–3 pm, and lowest between 7 and 9 am in the morning. The same pattern was consistent for both habitats (fern and grass) and distances from the wooded islands. GUDs decreased with distance from the woody islands in both fern and grass habitats and were significantly lower in the fern habitat. This activity pattern suggests that R. pumilio responds to a spectrum of spatially and temporally varying risks from a variety of predators including aerial predators that increase risk as they make use of mid-day thermals.

Accessibility Experience Lab: Discovering the Impact of Design on Disabilities

Many accessibility problems of devices and user interfaces could be avoided if the needs of people with disabilities were considered during the design process. This paper describes an accessibility experience lab module which introduces participants to both the barriers associated with disabilities and the impact that simple design changes can have on those barriers. The core of the lab is an experience session where participants are given functional limitations along with tasks at paired stations so they can compare their experiences on devices with inaccessible and accessible designs. For seven years the experience lab has been a part of the curriculum for first-year engineering students at the University of Wisconsin, and over 1700 students have completed it. In the popular lab, the students are engaged and report interest and insights into design for disabilities. Materials are available at www.trace.wisc.edu/training/explab/ .

Goodbye OSCE, hello CASC: a mock CASC course and examination

SummaryThe Clinical Assessment of Skills and Competencies (CASC) is the latest change to the MRCPsych examination. the CASC is a complex version of an Observed Structured Clinical Examination (OSCE) format, with paired stations, and is now the only clinical component in the MRCPsych examination. We describe how to organise a relatively inexpensive and workforce-light 1-day course and mock CASC examination by adapting a previously described method for running an OSCE workshop. We also evaluate the acceptability to trainees of a mock CASC examination and course, and describe their views on this new clinical examination format.

Effect of bottom type on catch rates of North Sea cod ( Gadus morhua) in surveys with commercial fishing vessels

Seven surveys with commercial fishing vessels were conducted during a collaborative fishermen–scientist project on the distribution of cod in the north-eastern North Sea between June 2006 and June 2008. A flyshooter, a trawler and a gillnetter participated in this study. In general, catch rates were substantially higher on gravel or stone bottom and at ship wrecks than on sand bottom. The difference in the catch rates between the two bottom categories at paired stations within a short distance was highly significant for all the three fishing methods. Similarly, average CPUE for most surveys was several times higher on rough than on smooth bottom. These differences were highly significant for early autumn surveys conducted with the flyshooter and trawler and all gillnet surveys, the summer surveys for the flyshooter and the gillnetter, but not for the winter surveys with the trawler and the flyshooter. The latter suggest that bottom type preference may change with season, e.g. with respect to spawning migrations in winter and in relation with changes in the availability of food during spring and summer.