Cold Climatic Conditions Research Articles

Blade and microblade industry at Helong Dadong, north-east China, during Marine Isotope Stage 2

Characterised by the extensive use of obsidian, a blade-based tool inventory and microblade technology, the late Upper Palaeolithic lithic assemblages of the Changbaishan Mountains are associated with the increasingly cold climatic conditions of Marine Isotope Stage 2, yet most remain poorly dated. Here, the authors present new radiocarbon dates associated with evolving blade and microblade toolkits at Helong Dadong, north-east China. At 27 300–24 100 BP, the lower cultural layers contain some of the earliest microblade technology in north-east Asia and highlight the importance of the Changbaishan Mountains in understanding changing hunter-gatherer lifeways in this region during MIS 2.

The last 20,000 years of climate change in the Iberian Peninsula characterized by the small-mammal assemblages

Climate and environments have undergone significant changes throughout the Earth's history, which are reflected in the faunal record. In that sense, small mammals provide valuable palaeoecological insights due to their close relationship with their associated environments. Our research investigates the dynamics of small mammal communities in the Iberian Peninsula from the Late Pleistocene to the Holocene, comparing regional environmental variations as well as anthropogenic impacts. Our review of the small mammal assemblages from 26 archaeological sites across the Iberian Peninsula revealed a differential response of the small mammal communities between the northern and southern areas. The colder climatic conditions which characterized the Late Pleistocene favoured the presence of mid-European species (e.g., Alexandromys (Oecomicrotus) oeconomus, Chionomys (Chionomys) nivalis) in northern regions until the Mid Holocene, while other taxa today restricted to northern Iberia (e.g., Arvicola amphibius, Microtus gr. (Euarvicola) arvalis, Sorex araneus-coronatus) reached southern regions during the Last Glacial Maximum but disappeared at the beginning of the Holocene period. Palaeoenvironmental reconstructions indicate predominantly open landscapes and colder climates in the Late Pleistocene, with increased forest cover during the Early-Mid Holocene in northern areas. In contrast, the southern regions exhibited more stable environments compared to the northern ones. Our results underscore how the great environmental diversity and interactions between natural and anthropogenic factors affected the composition of Iberian small mammal communities during the last 20,000 years. Most specifically, during the Late Holocene, biogeographical patterns of the small mammals are mostly affected by anthropic activities, with changes in the distribution of some species (Microtus (Iberomys) cabrerae), and the entrance of new ones (synanthropic species).

Hydrogeochemical Characteristics and Sulfate Source of Groundwater in Sangu Spring Basin, China

The Sangu Spring Basin is located in an important economic area, and groundwater is the main source of water for local life and industry. Understanding the sources of chemical components in groundwater is important for the development and utilization of groundwater. In this paper, we analyzed the origin of the chemical components of groundwater and their evolution in the Sangu Spring Basin using statistical analysis, Piper diagrams, Gibbs diagrams, ion ratios, and combined hydrochemistry–isotope analyses. The results show that the groundwater in the Sangu Spring Basin is mainly derived from atmospheric precipitation, that the groundwater in stagnant and confined environment zones was formed under colder climatic conditions, and that the surface water (SW) has a close hydraulic relation with the groundwater. Water–rock interaction is the main factor controlling the composition of groundwater. The compositions of groundwater are mainly derived from carbonate weathering, silicate weathering, and dissolution of gypsum. Na+ and K+ in groundwater mainly come from the dissolution of albite and potassium feldspar, rather than rock salt. Ion exchange occurs in karst groundwater (KGW) and fissure groundwater (FGW), and ion exchange is dominated by the exchange of Mg2+ and Ca2+ in the groundwater with Na+ and K+ in the rock or soil. Sulfate in groundwater is derived from dissolution of gypsum, infiltration of atmospheric precipitation, and leakage of SW. Groundwaters with the highest sulfate content are located in the vicinity of SW, as a result of receiving recharge from SW seepage. Groundwaters with higher sulfate contents are located in the stagnant and deeply buried zones, where sulfate is mainly derived from the dissolution of gypsum. SW seepage recharges groundwater, resulting in increased levels of Cl−, NO3− and SO42− in groundwater. These insights can provide assistance in the protection and effective management of groundwater.

The Magdalenian horse (Equus ferus arcelini) from Roc-aux-Sorciers (Angles-sur-l’Anglin, France): Seasonality and paleoecology

Roc-aux-Sorciers is one of the most emblematic sites of Magdalenian culture, particularly known for its bas-relief and high-relief sculpted frieze depicting animals and humans, dated to the Middle Magdalenian. The stratigraphic sequence contains archaeological deposits corresponding to the occupations from the Middle Magdalenian, overlain by deposits from the Upper Magdalenian. The study of the horse Equus ferus arcelini, the preferentially hunted species, was conducted through various approaches (paleontological, zooarchaeological, palaeoenvironmental, dental wear analyses) to highlight a possible adaptation of these animal populations to the climatic and environmental changes recorded within the Magdalenian sequence, and to better understand the subsistence strategies of Magdalenian groups towards this fauna. In the Middle Magdalenian, in a steppe environment under cold and dry climate conditions, the site was repeatedly occupied for long durations by Magdalenian sculptors. Seasonality data indicate horse hunting in all seasons, suggesting sedentary to semi-sedentary equine populations in the territory. The results are consistent with dental wear analyses. In the Upper Magdalenian, the climate was cold and wet, and the environment more diversified and semi-open. Dental wear analyses show that horses were adapted to a more diversified and less abrasive diet compared to those of the Middle Magdalenian. Occupations were characterised as brief and seasonal.

A sustainable floating dome biogas plants integrated with semi-transparent photovoltaic thermal collectors: Construction, production and economic analysis

The design and construction of a self-sustained solar photo-voltaic active thermal heating floating dome biogas plant (35 m3) offers an alternative solution for round year biogas production, managing food and agricultural waste, reducing greenhouse gas emissions and minimize pollution. Moreover, this proposed model addresses the challenge of achieving the desired operating temperature (35 ± 2 °C) specially during the cold climatic conditions, which often leads to low gas production and high hydraulic retention time in anaerobic digestion. The integration of solar modules with the biogas digester enables the utilization of thermal energy for slurry heating and electricity for force mode of operation, ultimately enhancing overall energy efficiency. However, to assess the performance of the system, proximate and ultimate analyses as well as a cost-benefit analysis were carried out, considering revenue, and costs associated with construction, operation, and maintenance. The plant produces a significant amount of gas (9–12 m3) and hot water (∼2000 L) replacing approximately one LPG cylinder/2 day as well as organic fertilizer. The economic analysis shows a positive net present value (19.5 lakhs), an internal rate of return (20%), and short discounted payback period (5.7 years). This highlights the economic feasibility of the proposed model and emphasizes the importance of considering economic factors in the design and implementation of sustainable energy solutions. Furthermore, this approach demonstrates the potential for sustainable development and the transition to cleaner and more efficient energy systems by integrating renewable energy generation, waste management, and cost reductions.

Study of Heat Distribution in Railway Switch Using Resistive Heater in Cold Climate Conditions

Study of Heat Distribution in Railway Switch Using Resistive Heater in Cold Climate Conditions

Comprehensive performance evaluation of HVAC systems integrated with direct air capture of CO2 in various climate zones

Direct Air Capture (DAC) is a rapidly evolving technology that extracts CO2 directly from ambient air. This study presents a comprehensive performance evaluation of integrating DAC in HVAC systems, which can reduce indoor CO2 concentration and improve energy efficiency of HVAC systems. The DAC equipment is modeled in Modelica based on isotherm and thermodynamic equations, and pressure drop curves of the CO2 sorbent described in literature. The model is validated with data from the literature, and then integrated into a typical HVAC system available in Modelica Buildings library. The HVAC system is a Variable Air Volume (VAV) with reheater system for a one-floor office building with standard ASHRAE 2006 control sequences. Demand control ventilation strategies are designed to reduce the outdoor air flowrates when indoor CO2 concentrations are lower than the threshold, which is to maximize the benefits of integrating DAC. Four cases are proposed to assess the impacts of integrating DAC and DCV in HVAC systems in 8 different ASHRAE climate zones in the USA. The results show that by integrating DAC unit into the HVAC system, the average indoor CO2 concentration can be significantly reduced by over 45 % against the baseline without a DAC unit. By integrating DCV, 0.39–21.66 % of annual energy savings and 226–9539 kg carbon emissions reduction are observed across different climate zones. The highest energy savings are found to be achieved with cold climatic conditions while the lowest energy savings occur with favorable weather.

Taxonomic and stable isotope analyses of mammal remains from the Lateglacial site of Grotta Polesini (central Italy): Paleoenviromental implications

ABSTRACTGrotta Polesini is one of the most famous paleontological and archaeological sites of central Italy, which testifies to its human occupation during the Lateglacial. The site comprises a cave system where systematic excavation campaigns have been carried out since the 1950s. In 1974, 656 mammal remains were collected but never studied. This fossil collection is here described for the first time through taxonomic and stable isotope analyses of the enamel of selected mammal teeth. The aim is to reconstruct the paleoenvironmental and climatic conditions of the site and to offer new information on terrestrial ecosystems during the Lateglacial in central Italy. The faunal assemblage studied herein, in addition to other species reported in previous works, suggests cold climate conditions. We also describe a right radius of an adult individual of Homo sapiens, increasing the human fossil record of the site. Carbon isotope data point to a scenario dominated by C3 plants in open and dry habitats, such as grasslands and steppes, in accordance with the pollen data from central Italy. The oxygen isotope data suggest the use of water resources with a local origin, i.e. local precipitation and surface waters with a provenance from the nearby Apennine chain. The ecology of the taxa influenced the oxygen isotope values, especially in the case of semi‐obligate to non‐obligate drinker species.

Performance of small-scale composting in low ambient temperatures: Effects of adding animal by-products and recycling leachates

Decentralized composting is an emerging method for managing biowaste, engaging waste generators as active recyclers in the waste management cycle. Evaluating performance and identifying optimization opportunities within this composting framework is essential to maximize its benefits and address its challenges. In small-scale composters, fresh waste is continuously mixed with previously added materials, shifting the typical composting process. As with larger systems, the composition of the feedstock influences the temperature profile and the quality of the final product. The issue of whether to include animal-source waste remains controversial in the development of standards and program guidelines. On the other hand, evaluating a leachate recycling method could help prevent nutrient loss and mitigate environmental impacts when bulking agents are lacking. In this study, kitchen and garden wastes were composted in 500-L static composters under cold climate conditions. We examined obtained compost stability, maturity, and quality parameters to determine the effects of adding animal by-product waste and/or recycling leachate. Our findings indicate that including animal by-products allows reaching sanitation temperatures under cold weather conditions and that recycling leachates could reduce nutrient losses and alleviate environmental and other user concerns while improving temperature, stability, maturity, and product quality patterns in decentralized composting.

Performance assessments of ground source heat pump assisted by various solar panels to achieve zero energy buildings in cold climate conditions

This paper aims to perform a comprehensive performance analysis of a solar-assisted ground source heat pump (SAGSHP) system connected to various types of solar panels to enhance overall energy efficiency. While previous studies have examined integrating solar panels with heat pumps, comprehensive solutions like those presented here and performance evaluations in the zero energy building context have been lacking. This study developed various scenarios using three types of solar panels, photovoltaic (PV), photovoltaic-thermal (PVT), and solar thermal collectors (ST), to explore their simultaneous use. TRNSYS software was employed to analyze the complex system, comparing it to a conventional natural gas boiler system as a baseline. The findings revealed that the on-site energy use intensity (EUI) decreased from 78.6 kWh/m2 to 53.3 kWh/m2, a reduction of approximately 33 %, due to the SAGSHP's implementation. The combination of PVT and PV panels emerged as the most suitable option for the SAGSHP, aligning with the net zero energy concept. The SAGSHP system achieved a low EUI of 10.4 kWh/m2 in terms of primary energy. Additionally, the solar fraction, indicating the proportion of solar energy used, reached approximately 90 %. Thus, this study underscores the significance of evaluating various solar panel configurations during the preliminary design phase of SAGSHP systems to optimize energy performance and progress toward zero energy buildings.

Adaptability and yield potential of quinoa as an introduction food crop under cold arid climatic conditions of Ladakh

Adaptability and yield potential of quinoa as an introduction food crop under cold arid climatic conditions of Ladakh

Holocene paleoclimatic records from Chakrata area, Northwest Himalaya

We present monsoon variability records for the Holocene using multi-proxy approach (environmental magnetism, carbon isotope, and total organic carbon) from a 146 cm thick sedimentary profile in the Kotikanasar meadow (Chakrata), Northwest Himalaya. The chronology of the record was constrained by five AMS 14C ages. The carbon isotope (δ13C) and Total Organic Carbon (TOC) data highly variable which vary between -26.62‰ and -22.46‰ (C3-plants) and 0.1 to ∼4%, respectively, indicating paleo-vegetation history and productivity of the studied area. The environmental magnetics indicates highly fluctuating in the Early Holocene with high concentrations of magnetic minerals during high monsoon conditions and vice-versa. Intense Indian Summer Monsoon (ISM) phases were identified during the Early and Late Holocene i.e., ∼9.2 to 7.4 ka, and ∼4.8 ka to Modern which shows warm and wet climate. While decline in the ISM intensity during ∼7.4 to 4.8 ka which indicates cold and dry climatic condition in the Northwest Himalayan regions. From ∼9.2 to 7.4 ka highly fluctuating climate linked with the Early Holocene warming. Sediment profile exhibits aridity in climate accompanying with the high influence of mid-latitude westerlies during ∼7.4 to 4.8 ka from Northwest Indian regions (Enzel et al., 1999). Hence the long-term fluctuation in the climate governed by the changes in the North Atlantic Ocean circulation as well as variations in the incoming solar radiations.

Multi-objectives occupant-centric control of thermostats and natural ventilation systems in cold climate conditions using real-time occupant-related information

Recently, Occupant-Centric Controls (OCCs) have attracted great attention. Many studies have applied OCCs to mechanical ventilation systems, while natural ventilation systems have gathered much less attention. The natural ventilation effect, driven by opening windows or vents, can be effective in improving indoor air quality, however, result in a leakage of interior heating energy in winter in cold climates. Therefore, the controls of thermostats and natural ventilation systems shall be designed well so that satisfying levels of thermal comfort, air quality and energy conservation can be simultaneously guaranteed. This study proposes an OCC and applies it to thermostats and natural ventilation systems for indoor thermal comfort, air quality and heating energy management. The strategy comprises three controllers: occupancy-based on-off controller, controller of setpoint of indoor air temperature and window openness controller. First, real-time profiles of heat gains from occupants and window openness were collected by employing vision-based detection. Second, a parametric building simulation study was conducted, and then simulation data were generated to develop predictive shallow artificial neural networks for forecasting the indoor conditions and energy performance of the investigated room. Third, the performance of the proposed strategy was examined. Compared to the baselines, the control could offer a decrease in building heating loads by between 43.4% and 63.8 % and an improvement of predicted mean vote levels by 0.36–0.37. The proposed OCC could also maintain indoor CO2 concentrations below 1000 ppm for about 91 % of the studied time, while 84.2 % of the time with several peaks over 3000 ppm in the baseline cases.

Reconstructing Younger Dryas ground temperature and snow thickness from cave deposits

Abstract. The Younger Dryas stadial was characterised by a rapid shift towards cold-climate conditions in the North Atlantic realm during the last deglaciation. While some climate parameters including atmospheric temperature and glacier extent are widely studied, empirical constraints on permafrost temperature and snow thickness are limited. To address this, we present a regional dataset of cryogenic cave carbonates (CCCs) from three caves in Great Britain that formed at temperatures between −2 and 0 °C. Our CCC record indicates that these permafrost temperatures persisted for most of the Younger Dryas. By combining ground temperatures with surface temperatures from high-resolution ground-truthed model simulations, we demonstrate that ground temperatures were approximately 6.6 ± 2.3 °C warmer than the mean annual air temperature. Our results suggest that the observed temperature offset between permafrost and the atmosphere can be explained by an average snow thickness between 0.2 and 0.9 m, which persisted for 233 ± 54 d per year. By identifying modern analogues from climate reanalysis data, we demonstrate that the inferred temperature and snow cover characteristics for the British Isles during the Younger Dryas are best explained by extreme temperature seasonality, comparable to continental parts of today's Arctic Archipelago. Such a climate for the British Isles necessitates a winter sea ice margin at approximately 45° N in the North Atlantic Ocean.

Formation of the crust on the surface of cold-climate aeolian quartz grains – A nano-scale study

Sand-sized quartz grains selected from sediments of a Pleistocene inland dune (eastern Poland) were subjected to a series of laboratory analyses, including grain-size distribution, morphoscopy analysis, microtextural analysis using scanning electron microscope (SEM) and nanostructural analysis using transmission electron microscope (TEM). The results indicate the presence of a crust on the surface of all of the studied quartz grains and a surprisingly low number of aeolian-induced mechanical microtextures. The TEM examination identifies illite-smectite assemblages as the main component of the crust, accompanied by amorphous silica, local accumulation of Fe, K, Ca, Mg oxides, and mineral particles (quartz, K-feldspar, chlorite). The thickness of the crust reaches approx. 0.1–0.2 μm and varies from the minimum on micro-protrusions up to the maximum in micro-cavities. Here, we present a new theory on the origin of the crust observed on the surface of cold-climate aeolian quartz grains. We postulate that the crust is formed within a near-surface saltation layer during active aeolian transport of sand-sized grains and clay-sized particles operating under cold-climate conditions. The development of abrasion features and the formation of the crust are interpreted here to occur simultaneously and continuously during the aeolian transport. The formation of the crust results from specific properties of aeolian transport (i.e. self-induced electrification and electrification mechanisms of quartz grains) and the quartz grains themselves (i.e. grain shape and surface microtopography).

Ecological evolution of salmonids

For the first time, ecological evolution of salmonid fishes is analyzed using the method of historical biogeography, considering formation of ecology and reproductive biology for these species under planetary climatic and geological changes. Climate cooling in the Cenozoic and associated reconstruction of the food base for salmonids had a major impact on evolution of their ecology. This process began at the Asian coast of the North Pacific much earlier than at the American coast and was much more intense there. The salmonids developed marine and oceanic feeding that led to their stocks increasing and a subsequent imbalance with freshwater prey. Adapting to this imbalance, the species of gen. Oncorhynchus came to irreversible reduction of organs and functions in the fresh water and absolute mortality of producers. Egg development lengthened in cold environments, and anadromous and semi-anadromous salmonid species were forced to spawn earlier, so that the larvae would hatch during the spring bloom of their prey. Gradually, the timing of their spawning shifted from early spring to winter and then to fall; accordingly, the spawning run to the rivers began earlier, in particular in the northern areas. The spawning season of atlantic salmon Salmo salar and brown trout Salmo trutta shifted to a fall and spring-summer spawning run in the north of their range and to a winter-spring and fall spawning run in the south of their range, but there is currently no reason to consider these runs as seasonal races, given that both cases evolved from a single run in the process of evolutionary changes when the spawning season was interrupted by either winter cooling or summer warming in the lower river reaches and at the coast. The northern and southern populations of salmonid fishes in the Pacific separated, too, because of these ecological changes in the late Pliocene, in conditions of cold climate. Being in isolation, they diverged enough to be considered as separate taxa rather than seasonal races.

Relative decline in density of Northern Hemisphere tree species in warm and arid regions of their climate niches

Although climate change is expected to drive tree species toward colder and wetter regions of their distribution, broadscale empirical evidence is lacking. One possibility is that past and present human activities in forests obscure or alter the effects of climate. Here, using data from more than two million monitored trees from 73 widely distributed species, we quantify changes in tree species density within their climatic niches across Northern Hemisphere forests. We observe a reduction in mean density across species, coupled with a tendency toward increasing tree size. However, the direction and magnitude of changes in density exhibit considerable variability between species, influenced by stand development that results from previous stand-level disturbances. Remarkably, when accounting for stand development, our findings show a significant change in density toward cold and wet climatic conditions for 43% of the species, compared to only 14% of species significantly changing their density toward warm and arid conditions in both early- and late-development stands. The observed changes in climate-driven density showed no clear association with species traits related to drought tolerance, recruitment and dispersal capacity, or resource use, nor with the temperature or aridity affiliation of the species, leaving the underlying mechanism uncertain. Forest conservation policies and associated management strategies might want to consider anticipated long-term species range shifts alongside the integration of contemporary within-distribution density changes.

From freezing to functioning: cellular strategies of cold-adapted bacteria for surviving in extreme environments.

The ability of cold-adapted bacteria to survive in extreme cold and diverse temperatures is due to their unique attributes like cell membrane stability, up-regulation of peptidoglycan biosynthesis, increased production of extracellular polymeric substances, and expansion of membrane pigment. Various cold-adapted proteins, including ice-nucleating proteins (INPs), antifreeze proteins (AFPs), cold shock proteins (Csps), and cold-acclimated proteins (CAPs), help the bacteria to survive in these environments. To sustain cells from extreme cold conditions and maintain stability in temperature fluctuations, survival strategies at the molecular level and their mechanism play significant roles in adaptations in cryospheric conditions. Furthermore, cold shock domains present in the multifunctional cold shock proteins play crucial roles in their adaptation strategies. The considerable contribution of lipopeptides, osmolytes, and membrane pigments plays an integral part in their survival in extreme environments. This review summarizes the evolutionary history of cold-adapted bacteria and their molecular and cellular adaptation strategies to thrive in harsh cold environments. It also discusses the importance of carotenoids produced, lipid composition, cryoprotectants, proteins, and chaperones related to this adaptation. Furthermore, the functions and mechanisms of adaptations within the cell are discussed briefly. One can utilize and explore their potential in various biotechnology applications and their evolutionary journey by knowing the inherent mechanism of their molecular and cellular adaptation to cold climatic conditions. This review will help all branches of the life science community understand the basic microbiology of psychrophiles and their hidden prospect in life science research.

Thermal performance of an economical air heater for space heating using composite energy storage materials

ABSTRACT Energy storage materials have the potential to improve the performance of thermal systems due to their excellent thermo-physical properties. Different energy storage materials have been tested for different thermal systems and found adequate to improve their thermal performance. Present work focuses, (i) on the development of two different composite energy storage materials (CESM) by mixing graphite black powder (obtained from lithium batteries cells) in paraffin wax and coconut oil, and (ii) testing of these materials for solar space heating inside the two similar air heating systems namely, Model-2 and Model-3. Air heating trials have been conducted on four different configurations by placing CESM-filled containers on the absorber of the tested heaters. Results of natural and forced convective operations have been compared with a similar conventional air heater (Model-1) and also to some other relevant works on air heating systems. Results revealed that Model-3 is the best model. For this system, improved heat transfer was observed at 356.20 W/m2.K, thermal efficiency was observed at about 78.8%, overall heat loss was computed at 5.91 W/m2.K and maximum exhaust air temperature was observed at about 322.05 K. The cost of Model-3 was about $51.14 (₹ 4110 in Indian currency). Model-3 can be easily developed and used for air heating and drying operations under mild cold climate conditions.

Climate variability in northern Africa during the late Holocene: A multiproxy perspective from El-Beida Lake (Wadi El-Natrun, Egypt)

North Africa is a key region hosting ca. 230 million people that are dependent on climate to maintain their subsistence through agriculture. Because of the current global changes, understanding the mechanisms behind the climate variations that occurred in this region is extremely important. To contribute to a more accurate modelling projection, we reconstructed the paleoclimatic and paleoenvironmental variations from the Meghalayan (∼1,500 ka) to recent using palynological and geochemical data from a sediment core from El-Beida Lake (Wadi El-Natrun area, north Western Desert of Egypt). North Africa underwent significant shifts in climatic conditions forced by different drivers since the Roman Warm Period (RWP) until recent. Our sediment core record indicates that this region experienced a persistent dry and warm climate during the RWP until the first half of the Medieval Climate Anomaly (MCA). The positive North Atlantic Oscillation was the main driver for controlling the precipitation pattern and pushing the precipitation towards central and north Europe and favoring the dry climate in North Africa during the RWP. The dry and slightly cold conditions in the study area during the Dark Age Cold Period (DACP) can be ascribed to the coupling between the more southward position of the Azores Front and the weak Atlantic Meridional Overturning Circulation. Northern Africa showed variable climatic conditions during the Medieval Climate Anomaly (MCA) due to the complicated thermohaline circulation of the Mediterranean Sea. During this time, the Eastern Mediterranean experienced a cold or partially cold MCA that may be extended to the present study area. An abrupt change to humid and cold climatic conditions occurred in northern Africa during the Little Ice Age (LIA) due to large-scale processes like the ENSO and NAO. The SST warming of the North Tropical Atlantic (NTA), significantly influenced by ENSO, causes the position of the Atlantic ITCZ to be shifted northward affecting precipitation in Africa.