High-latitude Locations Research Articles

Performance Analysis of a Solar DHW System with Adsorption Module Operating in Different World Locations

A numerical study was conducted on the performance of a solar domestic hot water storage system with an adsorption module operating in seven different world locations. The base system was optimized for Portuguese conditions and, without changing the system itself and the water consumption profile, its performance was investigated by altering local installation and operating conditions and solar collector inclination angles. The overall dynamical model of the system was used for numerical simulations. The improved performance of the system was assessed by the reduction achieved on the annual energy consumption of a backup water heater when compared with a similar conventional energy storage system (without an adsorption module). The results showed that the best performances were obtained in locations where winter and summer are clearly defined, especially locations where winters are colder, and with solar collectors’ inclination angles larger than the local latitude, except for locations with low latitudes, where solar collectors’ inclination angles are not so relevant to the system performance. It was also discussed how the performance results must be carefully analyzed, as for low-latitude locations the absolute savings are in fact smaller even if their relative values are of the same order or even higher than for higher-latitude locations.

Optimization of the mixture of building types in a neighborhood and their energy and environmental performance

This paper presents optimization technique of residential and commercial buildings mixture within a mixed-use neighborhood, for enhanced energy performance and less GHG emission. The study, conducted for a Northern high latitude location, investigates several parameters related to building types, their density, floor area as well as ratio of specific building types to the total built area. Several methods are employed in the investigation, including energy simulations, statistical methods, optimization and decision making. A selection method of single optimal neighborhood scenario, based on the analysis of seasonal average hourly load is proposed. The results show that an optimal commercial to built land area ranges between 22% and 32%, with the remaining area dedicated to residential buildings. Multiple combinations of residential buildings that enhance energy performance while reducing GHG emissions are formed by 50% of detached houses and 50% of combined townhouses and apartment units (with different ratios). On the commercial side, near optimal combinations of commercial buildings area is constituted by 46–75% offices, 18–45% retails, and 6–9% supermarkets. Optimizing the hourly energy load profile, a scenario combining commercial land area of 25% with equal composition of office and retail buildings (47.5%), to residential area consisting of equal proportion of single detached and townhouses (48% each) can be selected.

Spatial Epidemiology of Vitamin D Status in Mongolia

TPS 723: Low and middle income countries: sanitation infections and other health effects, Exhibition Hall, Ground floor, August 26, 2019, 3:00 PM - 4:30 PM Background: Most Mongolians are known to have low vitamin D levels because of low availability and lack of dietary habit of vitamin D-rich foods, including fish and mushrooms. Moreover, solar radiation is inadequate to induce cutaneous synthesis of pre-vitamin D in winters because of Mongolia’s high latitude and highland location. This study aims to determine the spatial status of vitamin D in Mongolians. Methods: Serum 25-hydroxyvitamin D [25(OH)D], the most abundant vitamin D metabolite in circulation, was measured in 541 healthy subjects (age: 10–64 years) living in six Mongolian provinces and capital, Ulaanbaatar. Furthermore, blood samples were collected between September and December 2016. Results: The mean (± standard deviation) serum 25(OH)D concentration was 16.6 (± 7.0) ng/mL (recommended value, ≥30.0 ng/mL); furthermore, 70.1% of subjects had “deficient” (<20 ng/mL) and 24.2% had “insufficient” (20≤, <30 ng/mL) levels. The 25(OH)D levels were significantly lower in females (14.9 ± 5.9 ng/mL) than in males (19.5 ± 7.8 ng/mL), although no differentiation was noted by age. Subjects from Ulaanbaatar exhibited the lowest levels of 25(OH)D (7.9 ± 2.6 ng/mL) compared with all provinces, with significant differences even if seasonal sampling blood was considered. Furthermore, the 25(OH)D levels were relatively high in provinces in southern Mongolia. Conclusions: Mongolians have deficient vitamin D levels, especially in Ulaanbaatar, which could be partly attributed to the impact of air pollution; Ulaanbaatar is the most air polluted area in Mongolia (annual mean: PM2.5, 6–10 times higher than the safety level), which decreases the amount of ultraviolet-B radiation required for the synthesis of pre-vitamin D. Therefore, a comprehensive policy, including dietary modification and the remedy for air pollution, is warranted.

Climatologies and long-term changes in mesospheric wind and wave measurements based on radar observations at high and mid latitudes

Abstract. We report on long-term observations of atmospheric parameters in the mesosphere and lower thermosphere (MLT) made over the last 2 decades. Within this study, we show, based on meteor wind measurement, the long-term variability of winds, tides, and kinetic energy of planetary and gravity waves. These measurements were done between the years 2002 and 2018 for the high-latitude location of Andenes (69.3∘ N, 16∘ E) and the mid-latitude locations of Juliusruh (54.6∘ N, 13.4∘ E) and Tavistock (43.3∘ N, 80.8∘ W). While the climatologies for each location show a similar pattern, the locations differ strongly with respect to the altitude and season of several parameters. Our results show annual wind tendencies for Andenes which are toward the south and to the west, with changes of up to 3 m s−1 per decade, while the mid-latitude locations show smaller opposite tendencies to negligible changes. The diurnal tides show nearly no significant long-term changes, while changes for the semidiurnal tides differ regarding altitude. Andenes shows only during winter a tidal weakening above 90 km, while for the Canadian Meteor Orbit Radar (CMOR) an enhancement of the semidiurnal tides during the winter and a weakening during fall occur. Furthermore, the kinetic energy for planetary waves showed strong peak values during winters which also featured the occurrence of sudden stratospheric warming. The influence of the 11-year solar cycle on the winds and tides is presented. The amplitudes of the mean winds exhibit a significant amplitude response for the zonal component below 82 km during summer and from November to December between 84 and 95 km at Andenes and CMOR. The semidiurnal tides (SDTs) show a clear 11-year response at all locations, from October to November.

Refugia under threat: Mass bleaching of coral assemblages in high-latitude eastern Australia.

Environmental anomalies that trigger adverse physiological responses and mortality are occurring with increasing frequency due to climate change. At species' range peripheries, environmental anomalies are particularly concerning because species often exist at their environmental tolerance limits and may not be able to migrate to escape unfavourable conditions. Here, we investigated the bleaching response and mortality of 14 coral genera across high-latitude eastern Australia during a global heat stress event in 2016. We evaluated whether the severity of assemblage-scale and genus-level bleaching responses was associated with cumulative heat stress and/or local environmental history, including long-term mean temperatures during the hottest month of each year (SSTLTMAX ), and annual fluctuations in water temperature (SSTVAR ) and solar irradiance (PARZVAR ). The most severely-bleached genera included species that were either endemic to the region (Pocillopora aliciae) or rare in the tropics (e.g. Porites heronensis). Pocillopora spp., in particular, showed high rates of immediate mortality. Bleaching severity of Pocillopora was high where SSTLTMAX was low or PARZVAR was high, whereas bleaching severity of Porites was directly associated with cumulative heat stress. While many tropical Acropora species are extremely vulnerable to bleaching, the Acropora species common at high latitudes, such as A. glauca and A. solitaryensis, showed little incidence of bleaching and immediate mortality. Two other regionally-abundant genera, Goniastrea and Turbinaria, were also largely unaffected by the thermal anomaly. The severity of assemblage-scale bleaching responses was poorly explained by the environmental parameters we examined. Instead, the severity of assemblage-scale bleaching was associated with local differences in species abundance and taxon-specific bleaching responses. The marked taxonomic disparity in bleaching severity, coupled with high mortality of high-latitude endemics, point to climate-driven simplification of assemblage structures and progressive homogenisation of reef functions at these high-latitude locations.

NORTHEAST PACIFIC SEAWATER RADIOCARBON RECORDED IN ABALONE SHELLS OBTAINED FROM OTSUCHI BAY, JAPAN

ABSTRACTReconstructing past ocean currents in the coastal regions is necessary to better understand the relationship between oceanographic changes and coastal ecosystems. It is known that variations have occurred with large-scale climate changes such as ENSO (El Niño Southern Oscillations) and PDO (Pacific Decadal Oscillations). Thus, reconstruction of past seawater conditions in coastal regions is needed to better understand the relationship between oceanographic changes and coastal ecosystems. Seawater radiocarbon is a unique proxy to understand the properties of water masses. Reef-building corals have been employed extensively and successfully in conducting this type of research into past ocean circulation histories. However, their distribution is limited to the low latitudes and hence alternative archives are required for studies in mid to high-latitude locations. Here, we use abalone shell samples obtained from Otsuchi Bay located in the Tohoku region on the Pacific coast of Northern Japan. Radiocarbon in abalone shells was compared with dissolved inorganic carbon in two-year-long records of river water as well as seawater. The data indicate that abalone shells can be used to reconstruct past seawater radiocarbon variations in northern Japan where coral skeletons are not available for ocean mixing studies.

Environmental radiation dosimetry at high southern latitudes with Liulin type instruments

Because of the geomagnetic field shape, the polar regions are the most exposed to secondary particles and radiation produced by primary cosmic rays in the atmosphere. At present, only few experimental measurements of environmental dose are reported in literature at high southern latitudes. A three year campaign has been carried out in two different locations, Ushuaia (Argentina, 54.80∘ S, 68.30∘ W) and Marambio (Antarctica, 64.24∘ S, 56.63∘ W), using a Liulin type detector, allowing to measure the total environmental radiation flux and dose. The Liulin type instrument, measuring the energy deposition in a silicon detector, is especially suitable to evaluate the dose, separating the low and high LET (Linear Energy Transfer) components. The instrument was installed at the GAW Station in Ushuaia and inside the LAMBI Laboratory at the Marambio Antarctic base. In December 2017 preliminary measurements have been carried out at the French-Italian base Dome C, at 3233 m a.s.l., with a Liulin-AR, a new version of Liulin spectrometer, specifically built for this application by the Space Research and Technology Institute of Bulgarian Academy of Sciences. In this paper the environmental dose values obtained in the different southern high latitude locations are compared and discussed.

Physiological performance of ballan wrasse (Labrus bergylta) at different temperatures and its implication for cleaner fish usage in salmon aquaculture

Ballan wrasse (Labrus bergylta) are used extensively as cleaner fish to control salmon lice (Lepeophtheirus salmonis) infestations in the Atlantic salmon (Salmon salar) aquaculture industry. Fish are either cultured or caught in the wild before being transferred to salmon sea cages. Ballan wrasse are a poorly studied species, and fundamental knowledge of physiological performances and environmental limits are therefore needed for better deployment strategies and to predict when animal welfare may be at risk. We acclimated ballan wrasse for a minimum of 2 weeks to 5, 10, 15, 20 and 25 °C, representing the full range of temperatures wrasse may experience in salmon sea cages. Swim tunnel respirometry was performed at each temperature to measure standard and maximum metabolic rates, aerobic scope, and critical swimming speed (Ucrit). No mortalities occurred at any acclimation temperature. However, fish were generally inactive at lower temperatures, as evidenced by low metabolic rates. It was not possible to stimulate fish to swim continuously between 5 and 20 °C, and Ucrit was only obtained at 25 °C as 27 cm s−1 (1.1 body lengths s−1). The aerobic scope increased throughout the thermal interval tested from 129 ± 7 mg O2 kg−1 h−1 at 5 °C to 265 ± 18 mg O2 kg−1 h−1 at 25 °C. Owing to weak swimming capabilities, ballan wrasse deployment at locations with moderate to strong current speeds will likely result in poor welfare. Low metabolic rates and inactivity at 5–10 °C suggests that their efficiency as cleaner fish will be limited in winter and in higher latitude locations. Overall, ballan wrasse differs substantially from Atlantic salmon in physiology, behaviour and morphology, and may not thrive in some farm environments suitable for salmon.

Formation of coarse sediment lags in ice-sediment mixtures: A geomorphic signature of sublimation on regolith surfaces

In many high-latitude locations on Mars, boulder sized clasts are present at the ground surface atop finer-grained sediments. These areas are concentrated in the latitude dependent mantle (LDM), an ice-rich surface unit that is globally distributed polewards of ∼30° latitude. Here, we test the hypothesis that sublimation of buried ice can drive grain size sorting in clastic deposits. We conducted pilot laboratory experiments to determine how buried and interstitial dry ice (CO2) sublimation modifies the grain size distribution in overlying and intermingled lithic sediments. We found that sublimation can sort grains into horizons with distinct grain size distributions by allowing fines to winnow into space freed by sublimation of underlying ice. On sloped surfaces, this mechanism enables lateral sorting by concentrating large grains on the surface and allowing them to slide or roll downslope. We infer that sublimation-driven sorting may affect the surface grain size distribution of solar system objects for which solid-vapor phase transitions dominate (e.g., modern Mars, comet 67P/Churyumov-Gerasimenko, asteroids, etc.).

Winter hardiness of Miscanthus (III): Genome‐wide association and genomic prediction for overwintering ability in Miscanthus sinensis

AbstractOverwintering ability is an important selection criterion for Miscanthus breeding in temperate regions. Insufficient overwintering ability of the currently leading Miscanthus biomass cultivar, M. ×giganteus (M×g) ‘1993–1780', in regions where average annual minimum temperatures are −26.1°C (USDA hardiness zone 5) or lower poses a pressing need to develop new cultivars with superior cold tolerance. To facilitate breeding of Miscanthus, this study characterized phenotypic and genetic variation of overwintering ability in an M. sinensis germplasm panel consisting of 564 accessions, evaluated in field trials at three locations in North America and two in Asia. Genome‐wide association (GWA) and genomic prediction analyses were performed. The Korea/N China M. sinensis genetic group is a valuable gene pool for cold tolerance. The Yangtze‐Qinling, Southern Japan, and Northern Japan genetic groups were also potential sources of cold tolerance. A total of 73 marker–trait associations were detected for overwintering ability. Estimated breeding value for overwintering ability based on these 73 markers could explain 55% of the variation for first winter overwintering ability among M. sinensis. Average genomic prediction ability for overwintering ability across 50 fivefold cross‐validations was high (~0.73) after accounting for population structure. Common genomic regions for overwintering ability were detected by GWA analyses and a previous parallel QTL mapping study using three interconnected biparental F1 populations. One QTL on Miscanthus LG 8 encompassed five GWA hits and a known cold‐responsive gene, COR47. The other overwintering ability QTL on Miscanthus LG 11 contained two GWA hits and three known cold stress‐related genes, carboxylesterase 13 (CEX13), WRKY2 transcription factor, and cold shock domain (CSDP1). Miscanthus accessions collected from high latitude locations with cold winters had higher rates of overwintering, and more alleles for overwintering, than accessions collected from southern locations with mild winters.

Solar radiation estimation at high latitudes: Assessment of the CMSAF databases, ASR and ERA5

There is a growing demand for the estimation of solar energy potential at high latitude locations. This study compares four datasets; Cloud, Albedo, Radiation dataset Edition 2 (CLARA), Surface Solar Radiation dataset – Heliosat Edition 2 (SARAH), ECMWF Reanalysis 5 (ERA5) and Arctic System Reanalysis v2 (ASR) on high latitude locations. Global horizontal irradiance (GHI) from these datasets is compared with in-situ ground-measurements over multiple locations in Norway. The first two datasets are mainly based on satellite estimation of solar radiation, while the latter two are based on a combination of a weather-prediction model, satellite data, and other observations. The datasets are evaluated against quality-controlled in-situ measurements of solar radiation from pyranometers. Overall, CLARA, SARAH, and ERA5 show moderate errors, while those of ASR are considerably larger. Monthly averages of global horizontal irradiance have mean absolute deviation (MAD) of 5.6 Wm−2, 5.0 Wm−2, 6.8 Wm−2, and 16.1 Wm−2 for CLARA, SARAH, ERA5, and ASR, respectively. Seasonal error analysis of these datasets reveals that CLARA and SARAH have low errors in all seasons. The datasets are classified into clear-sky, intermediate-cloudiness, and overcast categories, by using two thresholds of cloudiness based on the ratio of radiation at ground to its corresponding clear-sky value (clear-sky index). The categories obtained from satellite and reanalysis data are then compared against estimates based on corresponding in-situ observations; this analysis shows that both CLARA and SARAH perform better than ERA5 and ASR for these categories. SARAH and CLARA perform similarly in all types of conditions, but a gradual increase in errors for an increase of cloudiness is observed for ERA5 and ASR. Yearly energy analysis shows that CLARA performs better than other datasets for locations above latitude 65°N, and SARAH performs better in locations below 65°N. A further analysis is performed to assess the cloud sensing abilities of ERA5. On a shorter time scale, there are errors due to inaccurate representation of clouds, however on longer time scales i.e. months and years, these errors are considerably reduced. ERA5 is observed to overestimate TCWC (the total cloud water content defined as the mass of water and ice in a cloud) in clear-sky and intermediate-cloudy categories, while in overcast category it is underestimated. Generally, an overestimation of solar radiation is observed in reanalysis and an underestimation is observed in satellite methods.

The Ocean Observatories Initiative

The Ocean Observatories Initiative (OOI) is an integrated network that enables scientific investigation of interlinked physical, chemical, biological and geological processes throughout the global ocean. With near real-time data delivery via a common Cyberinfrastructure, the OOI instruments two contrasting ocean systems at three scales. The Regional Cabled Array instruments a tectonic plate and overlying ocean in the northeast Pacific, providing a permanent electro-optical cable connecting multiple seafloor nodes that provide high power and bandwidth to seafloor sensors and moorings with instrumented wire crawlers, all with speed-of-light interactive capabilities. Coastal arrays include the Pioneer Array, a relocatable system currently quantifying the New England shelf-break front, and the Endurance Array, a fixed system off Washington and Oregon with connections to the Regional Cabled Array. The Global Arrays host deep-ocean moorings and gliders to provide interdisciplinary measurements of the water column, mesoscale variability, and air-sea fluxes at critical high latitude locations. The OOI has unique aspects relevant to the international ocean observing community. The OOI uses common sensor types, verification protocols, and data formats across multiple platform types in diverse oceanographic regimes. OOI observing is sustained, with initial deployment in 2013 and 25 years of operation planned. The OOI is distributed among sites selected for scientific relevance based on community input and linked by important oceanographic processes. Scientific highlights include real-time observations of a submarine volcanic eruption, time-series observations of methane bubble plumes from Southern Hydrate Ridge off Oregon, observations of anomalous low-salinity pulses off Oregon, discovery of new mechanisms for intrusions of the Gulf Stream onto the shelf in the Middle Atlantic Bight, documentation of deep winter convection in the Irminger Sea, and observations of extreme surface forcing at the most southerly surface mooring in the world ocean.

Regional variability in reproductive traits of the Acropora hyacinthus species complex in the Western Pacific Region.

Understanding natural variations in the life history traits of reef-building corals under different environmental conditions is an area of active research. This study compares variability in the reproductive and genetic traits of the hermaphroditic broadcast spawning coral Acropora hyacinthus, from the Western Pacific Region, across six different latitudes [Japan (33° and 31°N), Taiwan (23°, 22° and 21°N), and Indonesia (5°S)]. Egg sizes among corals in the lowest latitude studied were significantly larger than those at high latitudes, while the mean number of eggs were significantly different only among high latitude and two out of the three mid latitude locations studied. Egg numbers were significantly negatively correlated with egg and testis volumes, indicating reproductive trade-offs across locations. Female gonad volumes were smaller at high latitudes but significantly larger at lower latitudes, being positively correlated with seawater temperatures. Furthermore, high genetic similarities among populations suggest active gene flow among low-, mid- and high-latitude locations. An exception to this trend, the mid-latitude location of Penghu (off western Taiwan) formed an independent group with highly similar genetic and reproductive traits, suggesting reproductive isolation with local adaptations. This study reports natural spatial variations in the reproductive traits of A. hyacinthus at different latitudinal locations, which may serve as baseline information to predict how the life histories of corals in general respond to the impacts of climate change.

Seasonal dynamics of spatial distributions and overlap between Northeast Arctic cod (Gadus morhua) and capelin (Mallotus villosus) in the Barents Sea.

The trophic link between cod (Gadus sp.) and capelin (Mallotus sp.) is important in many panarctic ecosystems. Since the early 2000s, the Northeast Arctic cod stock (G. morhua) in the Barents Sea has increased greatly, and the sea has been exceptionally warm. Such changes have potentially large effects on species distributions and overlap, which in turn could affect the strength of species interactions. Due to its high latitude location, the Barents Sea has strong seasonal variation in physical conditions and interactions. To study drivers of variation in cod-capelin overlap, we use data from two annual surveys run in winter and in autumn of 2004–2015. We first model winter and autumn spatial distributions of mature and immature cod and capelin. We then calculate overlap from model predictions on a grid with similar spatial resolution as the survey data. Our approach allowed us to interpret changes in overlap as species-specific effects of stock size and temperature, while accounting for sampling variation due to sampling time and depth. We found that during winter both species expanded their distribution in response to increased stock sizes, but how strongly and where the expansion occurred varied. The effect of temperature on distributions varied in space, and differed for cod and capelin and for different components of the two species. The results for autumn were clearer and more consistent. Both species expanded their distribution areas as their stock sizes increased. A positive effect of temperature was found in the north-eastern Barents Sea, where temperatures were lowest at the start of the study. Overlap increased and shifted north-eastwards during the study period and remained high despite a decline in the capelin stock. The increased overlap during autumn could mainly be attributed to the shift in cod distribution with increased cod stock biomass.

Effects of Water Column Mixing and Stratification on Planktonic Primary Production and Dinitrogen Fixation on a Northern Red Sea Coral Reef.

The northern Red Sea experiences strong annual differences in environmental conditions due to its relative high-latitude location for coral reefs. This allows the study of regulatory effects by key environmental parameters (i.e., temperature, inorganic nutrient, and organic matter concentrations) on reef primary production and dinitrogen (N2) fixation, but related knowledge is scarce. Therefore, this study measured environmental parameters, primary production and N2 fixation of phytoplankton groups in the water overlying a coral reef in the Gulf of Aqaba. To this end, we used a comparative approach between mixed and stratified water column scenarios in a full year of seasonal observations. Findings revealed that inorganic nutrient concentrations were significantly higher in the mixed compared to the stratified period. While gross photosynthesis and N2 fixation rates remained similar, net photosynthesis decreased from mixed to stratified period. Net heterotrophic activity of the planktonic community increased significantly during the stratified compared to the mixed period. While inorganic nitrogen (N) availability was correlated with net photosynthesis over the year, N2 fixation only correlated with N availability during the mixed period. This emphasizes the complexity of planktonic trophodynamics in northern Red Sea coral reefs. Comparing mixed and stratified planktonic N2 fixation rates with those of benthic organisms and substrates revealed a close seasonal activity similarity between free-living pelagic and benthic diazotrophs. During the mixed period, N2 fixation potentially contributed up to 3% of planktonic primary production N demand. This contribution increased by ca. one order of magnitude to 21% during the stratified period. Planktonic N2 fixation is likely a significant N source for phytoplankton to maintain high photosynthesis under oligotrophic conditions in coral reefs, especially during stratified conditions.

Innovative thermal storage strategies for Fresnel-based concentrating solar plants with East-West orientation

A novel proposal to drive forward linear Fresnel technology within the solar market competitiveness is presented in this paper. It consists of two innovative storage strategies conceived for the management of a flexible three-tank thermal storage system of molten salts, which seeks the enhancement of part-load plant efficiency in alternative East-West oriented Fresnel solar plants. A consistent methodology has been developed in order to assess quantitatively this new proposal by means of annual performance simulations of a global model. This allows the comparison of the aforementioned approach of Fresnel-based plant with reference parabolic trough collectors (PTC) and linear Fresnel collectors (LFC), which are equipped with state-of-the-art two-tank thermal storage of molten salts and North-South solar field orientation. Results show an increase of more than 10% in annual plant efficiency compared to conventional North-South Fresnel plants based in high latitude locations, i.e. Almería (Spain). This boost in LFC performance would imply narrowing the gap with PTCs, where expensive high optical quality receivers are used. Findings in this paper state that the proposed innovative strategies are proven to be more effective when low quality receivers are used and when the solar fields are located far from tropics.

Dual Light Trapping and Water-Repellent Effects of a Flexible-Based Inverse Micro-Cone Array for Organic and Perovskite Solar Cells.

A simple and cost-effective fabrication process of a flexible-based inverse micro-cone array (i-MCA) structure textured on flexible transparent conductive electrodes (TCEs) was successfully demonstrated via a micro-imprinting process. The flexible i-MCA films exhibited an extremely high total transmittance of ∼93% and a haze of ∼95% with reduced reflectance while simultaneously demonstrating water-repellent properties. Introducing i-MCA on the illuminating side of organic solar cells (OSCs)- and perovskite solar cells-rigid glass substrate showed improved power conversion efficiencies (PCEs) due to the light trapping effect by multiple light bounces between cone array structures (forward scattering). This results in an increase of the optical path length in the photoactive layer. Similarly, flexible TCEs embedded with textured i-MCA increased the PCE by 14% for flexible OSCs. More importantly, i-MCA-TCE-based OSCs were highly flexible with 98% retention from the initial PCE at both 0° and at 60° even after 2000 bending cycles at a radius of 2 mm. This finding demonstrates that textured i-MCA is promising for improving: (a) the light harvesting efficiency of solar cells when installed in low-/high-latitude locations and (b) the wearable technology where a flexible device attached on curved objects could retain the PCE, even at an oblique angle, with respect to the normal incidence angle.

Future climate change projects positive impacts on sugarcane productivity in southern China

Abstract Climate change is recognised to alter the distribution of rainfall and increase temperature and atmospheric CO2 concentration [CO2] and pose a formidable challenge to the sustainability of various cropping industries around the world. Additionally, in specific regions, like China, and for particular crops, like sugarcane, the likely effects of climate change are not straightforward. This is because of non-linearity of the interacting climatic factors on crop growth and yield. In our study, the APSIM-Sugarcane model was used to examine the likely response of sugarcane in future climate scenarios. Statistically downscaled climate data based on 28 global climate models (GCMs) under RCP4.5 and RCP8.5 scenarios were used to generate the change in climate in southern China. The results show that the model well reproduced observations for biomass dry matter (DM), biomass fresh matter (FM), sugar yields (S) and leaf area index (LAI), with values for the index of agreement of 0.65, 0.71, 0.84 and 0.70, respectively. The values of RMSE were relatively low with 7.10 t ha−1 for DM, 18.87 t ha−1 for FM, 0.84 t ha−1 for S and 1.03 m2 m−2 for LAI. On average, the ensemble of downscaled GCM projections showed a small increase in radiation and rainfall in the future at the four locations considered, with significantly increased temperature. Sugarcane yields in southern China appeared to be positively affected under future climate and [CO2] changes. Overall, DM was projected to increase by 5.6 and 6.4 and 6.6 t ha−1 for RCP4.5 in 2030s, 2060s and 2090s relative to 1961–2010, respectively. However, RCP8.5 had less promotion compared to RCP4.5 on DM. Similar increased trends for three future time periods could be found in FM and S. Our results showed that the largest percentage change in S occurred at high latitude locations (e.g., Hezhou), with mean values 28.1% and 39.4% for RCP4.5 and RCP8.5 in 2030s, 44.2% and 23.5% in 2060s, and 41.1% and 45.5% for in 2090s, respectively. In addition, our multiple linear regression analyses showed that the changes in radiation, rainfall and temperature together with elevated [CO2] could explain more than 70% of sugarcane yields change across four locations. Across all locations, increases in sugarcane yields were strongly correlated (P = .001) with each degree (Celsius) increase in future temperature and per mm increase in future rainfall. For example, the DM, FM and S increased 7.8–14.2, 16.6–36.1 and 2.7–6.1 kg ha−1 mm−1 responding to rainfall, respectively. Although uncertainties in our study on the impact of climate change on sugarcane might arise from the choice of crop model and GCMs, the results would be pivotal for developing high-yield adaptive strategies as well as informing policy makers to improve sugarcane productivity in China.

Decadal changes in surface ozone at the tropical station Thiruvananthapuram (8.542° N, 76.858° E), India: effects of anthropogenic activities and meteorological variability.

This paper presents the first observational results from an Indian station on the long-term changes in surface ozone (O3)-a major environmental pollutant and green house gas-over a period of about 40years. It is based on the in situ measurements carried out during 1973-1975, 1983-1985, 1997-1998 and 2004-2014 at the tropical coastal station, Thiruvananthapuram. From 1973 to 1997, surface O3 shows a slow increase of ~ 0.1ppbyear-1 and a faster increase of 0.4ppbyear-1 afterwards till 2009 after which it showed a levelling off till 2012 followed by a minor decrease. The highest rate of increase is observed during 2005 to 2009 (2ppbyear-1), and the overall increase from 1973 to 2012 is ~ 10ppb. The increase in day time O3 (peak O3) is estimated as 0.42ppbyear-1 during 1997-2012 and 2.93ppbyear-1 during 2006-2012. Interestingly, the long-term trend in O3 showed seasonal dependence which is more pronounced during O3 peaking seasons (winter/summer). The observed trends were analysed in the light of the changes in NO2, a major outcome of anthropogenic activities and methane which has both natural and anthropogenic sources and also meteorological parameters. Surface O3 and NO x exhibited positive association, but with varying rate of increase of O3 for NO x < 4 and > 4ppb. Methane, a precursor of O3 also showed increase in tune with O3. Unlike many other high-latitude locations, meteorology plays a significant role in the long-term trends in O3 at this tropical site with water vapour abundance and strong solar irradiance which favour photochemistry. A comparison with the corresponding changes in the satellite-retrieved tropospheric column O3 (TCO) also showed an increase of 0.03DUyear-1 during 1996-2005 which enhanced to 0.12DUyear-1 after 2005. Both surface O3 and satellite-retrieved TCO were positively correlated with daily maximum temperature, increasing at the rate of 1.54ppb°C-1 and 1.9DU°C-1, respectively, on yearly basis. Surface O3 is found to be negatively correlated with water vapour content (ρv) at this tropical site, but at higher levels of ρv, O3 shows a positive trend.

Self-reported discomfort associated with Daylight Saving Time in Brazilian tropical and subtropical zones

Background: Daylight Saving Time (DST) annually moves clocks 1 hour forward, when daytime is longer than night. Previous studies from medium and high latitude locations have pointed to a disruptive effect of DST on human circadian rhythms. Since Brazil is an equatorial country implementing DST, a different relationship between photic and social synchronisers may interfere with DST effects.Aim: To explore the prevalence and duration of self-reported discomfort related to DST among Brazilian residents (latitude 12–33° S, longditude 39–57° W). It was hypothesised that an elevated prevalence of self-reported discomfort would be found in Brazil, due to the pronounced uncoupling between social and geophysical synchronisers.Subjects and methods: In total, 12 467 volunteers completed a web-based, Brazilian version of Horne-Östberg Morningness-Eveningness Questionnaire, provided demographic information, and answered questions related to DST complaints (discomfort, duration of discomfort).Results: Of the total sample, 45.43% reported no discomfort related to DST, with meaningful proportions for all chronotypes. However, eveningness was most associated with discomfort. About one fourth of the total sample reported discomfort over the whole DST period. Gender interaction is largely supported by these results.Conclusions: DST at low latitude locations may be disruptive for circadian rhythms, since seasonality of sunrise near the equator is negligible or very mild.