Summer Temperatures Research Articles

Future Climate Projections for South Florida: Improving the Accuracy of Air Temperature and Precipitation Extremes With a Hybrid Statistical Bias Correction Technique

AbstractProjecting future climate variables is essential for comprehending the potential impacts on hydroclimatic hazards like floods and droughts. Evaluating these impacts is challenging due to the coarse spatial resolution of global climate models (GCMs); therefore, bias correction is widely used. Here, we applied two statistical methods—standard empirical quantile mapping (EQM) and a hybrid approach, EQM with linear correction (EQM‐LIN)—to bias correct precipitation and air temperature simulated by nine GCMs. We used historical observations from 20 weather stations across South Florida to project future climate under three shared socioeconomic pathways (SSPs). Compared to the EQM, the hybrid EQM‐LIN method improved R2 of daily quantiles by up to 30% over the historical period and improved MAE up to 70% in months that contain most extreme values. Projected extreme precipitation at the weather stations showed that, compared to the EQM‐LIN, the EQM method underestimates the high quantiles by up to 26% in SSP585. The projected changes in annual maximum precipitation from historical period (1985–2014) to near future (2040–2069) and far future (2070–2100) were between 2% and 16% across the study area. Projected future precipitation suggested a slight decrease during summer but an increase in fall. This, along with rising summer temperatures, suggested that South Florida can experience rapid oscillations from warmer summers and increased flooding in fall under future climate. Additionally, our comparative analyses with globally and nationally downscaled studies showed that such coarse scale studies do not represent the climatic extremes well, particularly for high quantile precipitation.

Challenges to Viticulture in Montenegro under Climate Change

The Montenegrin climate is characterised as very heterogeneous due to its complex topography. The viticultural heritage, dating back to before the Roman empire, is settled in a Mediterranean climate region, located south of the capital Podgorica, where climate conditions favour red wine production. However, an overall increase in warmer and drier periods affects traditional viticulture. The present study aims to discuss climate change impacts on Montenegrin viticulture. Bioclimatic indices, ensembled from five climate models, were analysed for both historical (1981–2010) and future (2041–2070) periods upon three socio-economic pathways: SSP1-2.6, SSP3-7.0 and SSP5-8.5. CHELSA (≈1 km) was the selected dataset for this analysis. Obtained results for all scenarios have shown the suppression of baseline conditions for viticulture. The average summer temperature might reach around 29.5 °C, and the growing season average temperature could become higher than 23.5 °C, advancing phenological events. The Winkler index is estimated to range from 2900 °C up to 3100 °C, which is too hot for viticulture. Montenegrin viticulture requires the application of adaptation measures focused on reducing temperature-increase impacts. The implementation of adaptation measures shall start in the coming years, to assure the lasting productivity and sustainability of viticulture.

Incorporating projected climate conditions to map future riparian refugia

AbstractIdentifying areas expected to remain buffered from climate change and maintain biodiversity and ecological function (i.e., climate refugia) is important for climate adaptation planning. As structurally diverse transitional zones between terrestrial and aquatic environments, riparian areas are often biological hotspots and provide critical corridors for species movement, particularly in arid and semi‐arid regions. In our study region in the western and central USA, identifying riparian areas that could serve as climate refugia is a priority for wildlife managers. We mapped areas with connected riparian habitats that, based on landscape diversity and projected changes in summer temperatures and landscape runoff, are expected to serve as climate refugia. To incorporate uncertainty and balance the need for near‐ and long‐term planning, we mapped potential refugia for 2 future time periods (2040–2069, 2070–2099) based on 2 climate models that represented divergent but plausible climate outcomes. The approach we developed is not constrained by physiology or behavior of target species and can be used to identify areas expected to fare comparatively well under a wide range of future climate scenarios. Our approach can also be used to identify areas where restoration could increase riparian connectedness and climate resilience.

Understanding the influence of environmental factors on forest composition along the vertical gradient of Northwestern Himalaya

Temperate and alpine ecosystems are considered the most sensitive and vulnerable region towards climate change in the Indian Himalayan region. The current study investigates forest composition in relation to environmental and edaphic factors, which is critical for determining plant community patterns. The impact of climatic and soil properties was studied to better understand species diversity and composition over an elevational gradient (2500–4800 m) in Beas Valley, Northwestern Himalaya. A total of 181 species from 15 community types, representing 122 genera and 53 families (9 Trees, 13 shrubs, and 142 herbs) were recorded from the valley. Non-metric multidimensional scaling (NMDS) analysis revealed significant compositional dissimilarity (PseudoF = 10.16, R2 = 0.48, p < 0.001) among vegetation types. Structural equation modeling (SEM) results indicated that tree species diversity was significantly influenced by solar radiation (β=0.17, p = 0.001) and winter temperature (β=41.95, p = 0.017). It was observed that solar radiation and winter temperature shape the community types in high elevation temperate regions. In contrast, precipitation, solar radiation along with summer temperature determine the composition of sub-alpine communities, whereas solar radiation, winter temperature and soil pH determine the composition of alpine communities. This indicated that multiple environmental factors are responsible for this diversity. The research findings shed light on crucial factors influencing high elevation plant diversity, emphasizing the significance of understanding environmental correlations for effective conservation. This is pioneer study, which will act as a reference for future studies in Beas valley. This scientific foundation allows for prioritized conservation efforts, focusing on areas with specific environmental conditions influencing forest composition and plant diversity, ultimately contributing to better management and preservation of high elevation plant communities.

Extreme summer temperature anomalies over Greenland largely result from clear-sky radiation and circulation anomalies

The polar regions have been undergoing amplified warming in recent years. In particular, Greenland has experienced anomalously warm summers with intense melt rates. We employ a surface radiation budget framework to examine the causes for positive and negative summer temperature anomaly events over Greenland from 1979 to 2021. We found a dominant contribution of the clear-sky downwelling longwave radiation and the surface albedo feedback to temperature anomalies. Atmospheric temperature perturbations dominate the effect of anomalous emissivity on clear-sky downwelling longwave radiation. In warm years, enhanced turbulent heat exchange due to increased surface temperature and diabatic warming in the troposphere induces adiabatic heating of the atmosphere, enhanced moisture advection, and a high-pressure anomaly with a blocking-like anti-cyclonic circulation anomaly following peak temperature days. Different modes of natural climate variability, in particular, related to blocking over Greenland, can further amplify or dampen the ongoing warming trend, causing extreme temperature events.

Physicochemical properties dominating the behaviors of short/medium chain chlorinated paraffins in the atmosphere

Chlorinated paraffins (CPs) are chlorinated alkane mixtures widely used as flame retardants and plasticizers in multiple industrial products. Systematic research on how homolog-specific properties affect their atmospheric behaviors is limited. Herein, we investigated the levels of short-chain CPs (SCCPs) and medium-chain CPs (MCCPs) in long-timescale, seasonal, and size-fractioned particles in the urban area of Dalian, a coastal city in northern China. The average SCCP and MCCP concentrations in particles with diameters ≤ 10 µm were 3.36 and 4.89 ng/m3, respectively, and a general increase in the SCCP concentration was observed from 2.59 ng/m3 in 2018 – 2019 to 7.84 ng/m3 in 2021 – 2023. CP levels and patterns showed significant seasonal variation, with a higher abundance of C11–13Cl7–9 in winter and C10–12Cl5 in summer. Elevated particle levels in winter and high temperatures in summer contributed to the seasonal variations. SCCPs and MCCPs were concentrated on particles with diameters of < 1 µm and their geometric mean diameter increased with the increasing carbon and chlorine numbers. Total Daily intake of SCCP and MCCP was calculated to be 0.15 and 0.22 ng/kg bw/day for adults. 53.1 %, 8.5 %, and 38.4 % of inhaled SCCPs, and 60.6 %, 7.6 %, and 31.8 % of inhaled MCCPs deposited into the head airway, tracheobronchial region, and alveolar region, respectively. This study reports on how homolog-specific physicochemical properties alter the temporal variations, size distributions, and inhaled fractions of CPs.

Heat-shock transcription factor HsfA8a regulates heat stress response in Sorbus pohuashanensis.

The SpHsfA8a upregulated expression can induce the expression of multiple heat-tolerance genes, and increase the tolerance of Arabidopsis thaliana to high-temperature stress. Sorbus pohuashanensis is an ornamental tree used in courtyards. However, given its poor thermotolerance, the leaves experience sunburn owing to high temperatures in summer, severely affecting its ornamental value. Heat-shock transcription factors play a critical regulatory role in the plant response to heat stress. To explore the heat-tolerance-related genes of S. pohuashanensis to increase the tree's high-temperature tolerance, the SpHsfA8a gene was cloned from S. pohuashanensis, and its structure and expression patterns in different tissues and under abiotic stresswere analyzed, as well as its function in heat tolerance, was determined via overexpression in Arabidopsis thaliana. The results showed that SpHsfA8a encodes 416 amino acids with a predicted molecular weight of 47.18kDa and an isoelectric point of 4.63. SpHsfA8a is a hydrophilic protein without a signal peptide and multiple phosphorylation sites. It also contains a typical DNA-binding domain and is similar to MdHsfA8a in Malus domestica and PbHsfA8 in Pyrus bretschneideri. In S. pohuashanensis, SpHsfA8a is highly expressed in the roots and fruits and is strongly induced under high-temperature stress in leaves. The heterologous expression of SpHsfA8a in A. thaliana resulted in a considerably stronger growth status than that of the wild type after 6h of treatment at 45°C. Its proline content, catalase and peroxidase activities also significantly increased, indicating that the SpHsfA8a gene increased the tolerance of A. thaliana to high-temperature stress. SpHsfA8a could induce the expression of multiple heat-tolerance genes in A. thaliana, indicating that SpHsfA8a could strengthen the tolerance of A. thaliana to high-temperature stress through a complex regulatory network. The results of this study lay the foundation for further elucidation of the regulatory mechanism of SpHsfA8a in response of S. pohuashanensis to high-temperature stress.

Carbon and oxygen isotopes in mummified wood reveal warmer and wetter winters in the Siberian Arctic 3000 years ago

Paleoclimate reconstructions from the Holocene are important for defining baseline conditions in order to interpret and contextualize the effects of modern climate change. Such records are particularly lacking for Siberia, a region that represents ~ 50% of the Arctic. In addition, the majority of proxy-based paleoclimate reconstructions for the Holocene represent mean annual conditions, and few quantify winter temperature, which is particularly important for predicting the effects of global warming in Arctic environments. Here we provide the first quantitative proxy reconstruction of precipitation and temperature for both summer and winter for 3000 years ago via novel high-resolution intra-annual carbon and oxygen isotope measurements across annual growth rings of fossil wood mummified within the permafrost of far northeastern Siberia. We found that the site experienced greater precipitation year-round (~ 10% increase in summer and ~ 30% increase in winter), cooler summer temperatures, and warmer winter temperatures, compared with today. Our findings indicate that warmer winter temperatures (+ 3.0 °C above early twentieth century values) in the Arctic 3000 years ago drove higher mean annual temperature by up to 1 °C, despite the existence of cooler summers, a similar phenomenon to what is observed within today’s Arctic environments, and past intervals of extreme global warmth.

Forecast models for start and peak dates of Poaceae pollen season in Tétouan (NW Morocco) using multiple regression analysis.

Poaceae pollen is one of the most widespread sources of aeroallergens in the world. The aim of this study is to build predictive models for the pollen season start day (PSsd) and peak dates of the Poaceae pollen season and thus give an overview of the climatic parameters that have the greatest influence. In Tétouan, sampling was carried out using a volumetric spore trap of the Burkard Hirst type. The relationships between the PSsd, peak dates and meteorological parameters were determined using correlation analysis. The models were constructed using multiple regression analysis with data from 2008 to 2019 and tested on data from 2022. The PSsd was especially significantly influenced by minimum temperature during winter and precipitation in the autumn of the previous year. The peak dates were significantly correlated with precipitation in January, March and April, but not with temperature. Three models were obtained for each of the season's parameters; the most accurate model for the PSsd explained a variability of 61% and includes as main predictors rainfall from the autumn of the previous year and the mean daily average temperature from 23 February to 8 March. The two most efficient peak dates models included precipitation in January and April as the main predictor variables, and explained greater variability (87 and 88%). Precipitation in autumn and the mean daily and the sum of minimum temperature in winter, showed significant decreasing tendencies. However, the PSsd trend delay was not statistically significant. This study draws the importance of the weather during preseason for grass pollen production and emphasises the usefulness of the models for allergic patients to take preventive measures and for healthcare professionals in allergy therapy.

Wastewater as a nutrient source for hydroponic production of lettuce: Summer and winter growth

Solutions combining soilless cropping systems with wastewater reuse can offer benefits in the agriculture sector, reducing pressure on water resources, promoting sustainable production, and reclaiming wastewater. However, assessing the sanitary risks associated with wastewater reuse is of utmost importance. This study aimed to investigate the hydroponic growth of lettuce (Lactuca sativa var. crispa L.) in wastewater from an urban treatment plant with different levels of treatment and evaluate potential sanitary risks. Crop growth took place in a greenhouse, during summer and winter periods, using wastewater after primary (PTW) or secondary (STW) treatment, and a nutrient solution (NS), as control. Physical and chemical water quality parameters, morphological crop growth parameters, and environmental conditions inside the greenhouse were monitored. Toxicity analyses were carried out through cell viability assays with the Caco-2 cell line and total coliforms and Escherichia coli (E. coli) were determined. Wastewater-grown plants achieved acceptable growth, even though presenting lower fresh weight than NS-plants. STW-plants’ growth was limited essentially by nutrient deficiency, and PTW-plants were affected by nutrient deficiency, pH values, solid load, and N-NO2 concentration. Higher temperatures in summer led to faster crop growth, and lower temperatures in winter allowed better nutrient uptake by the crop. Wastewater-grown plants did not evidence toxicity in leaf extracts up to 1 % w/v. Coliform enumeration data indicated an accumulation in plant roots, with high removal from the wastewater. E. coli was not detected on plants’ leaves and total coliforms were within acceptable limits. Furthermore, the results point to an improvement in the wastewater quality, with minimum removal values of 75.2 % BOD5, 83.1 % COD, 43.4 % P, 44.9 % N, and 90.4 % K. The results demonstrated the viability of wastewater reuse for hydroponic production allowing a better understanding of its processes and contributing to mitigating water scarcity for food production, and the impacts of treated wastewater discharge in freshwater courses, particularly those associated with nutrient delivery to aquatic systems.

Pollen-based seasonal temperature reconstruction in Northeast China over the past 10,000 years, and its implications for understanding the Holocene Temperature Conundrum

The Holocene Temperature Conundrum refers to the mismatch between proxy-based temperature records and those based on climate model simulations. A possible reason for this mismatch is a putative proxy-based bias in reconstructed summer temperatures, and therefore, regional reconstructions of seasonal temperature are crucial for resolving the conundrum. In this paper, we reconstruct vegetation and climate changes over the last ∼10,000 years BP based on a high-resolution pollen record from Gushantun peatland, Changbai Mountains, Northeast China. Multiple quantitative reconstruction approaches were used and weighted averaging partial least squares regression (WAPLS) was found to be the most appropriate method for reconstructing Holocene temperature and precipitation. The reconstructed climate record shows that the Holocene Climate Optimum occurred between 8 ka and 6 ka and exhibited a cold month mean temperature that was 3 °C warmer than modern temperatures. Climate gradually cooled during late Holocene with a minimum cold month temperature of −19.6 °C. Four prominent cold events occurred around 8.7 ka BP, 7.8 ka BP, 5.7 ka BP, and 2.5 ka BP with an amplitude variation up to 3 °C. The synthesized seasonal temperature time series and a comparison with other proxies show that the decreasing trend in mean annual temperature is not a seasonal bias caused by summer temperature change. This study provides evidence of a Holocene seasonal temperature change at a regional scale and insights for further understanding of the Holocene Temperature Conundrum.

Research on the evaluation of occupants' work efficiency in summer thermal environment of special vehicles based on subjective thermal sensation

High summer temperatures in special vehicle cabins affect drivers and occupants, reducing efficiency and combat potential. Improving occupant work efficiency is key to enhancing overall combat effectiveness. There's a lack of research on the work efficiency of special vehicle occupants engaged in complex, specialized tasks within cabin thermal environments. This study focused on a special vehicle, discussing the effects of the summer thermal environment in the cabin on personnel efficiency. It linked subjective thermal sensations to work efficiency through questionnaires and task performance evaluations. The best work efficiency environment may not be the environment with the highest thermal comfort. This paper presented a subjective thermal sensation range criterion for maintaining the work efficiency of the occupants in the cabin during the summer. This serves as a basis for optimizing the summer thermal environment and improving the reliability of human-vehicle systems in special vehicle cabins.

Predicting key ectotherm population mortality in response to dynamic marine heatwaves: A Bayesian‐enhanced thermal tolerance landscape approach

Abstract As climate change intensifies heatwaves, quantifying associated mortality within ectothermic populations is crucial for effective conservation. Thermal tolerance landscape (TTL) models are useful predictive tools that assume exponentially decreasing survival durations in individuals with increasing temperatures. This assumption has been validated through regression analyses on data from constant temperature experiments, primarily focusing on adult‐stage individuals. However, this approach does not allow for direct model validation with data from dynamic, real‐world heatwave events and overlooks early recruitment stage vulnerabilities. This study aimed to address these gaps using the blue mussel Mytilus, a foundation species forming extensive reefs along temperate coasts, as a model organism. We monitored survival rates of mussels (juveniles and adults) under constant heatwave (CHW) conditions in a laboratory experiment and under dynamic heatwave (DHW) scenarios simulated in an outdoor mesocosm experiment. Post‐heatwaves, we also assessed recruitment rates within the mesocosms. TTL models were parametrised by employing Approximate Bayesian Computation with Sequential Monte Carlo (ABC‐SMC) on each dataset separately. The parameter distributions were similar across both experiments, and the ABC‐SMC model predictions closely matched the observed survival declines, validating these models. In comparison, we found a lower predictive performance when using a Bayesian regression approach. Additionally, our best‐fit model predicted that warming across the non‐fatal DHW regimes would increase sublethal effects on mussels. The observed impact on the recruitment stage was more pronounced, with the recruitment rate following an exponential decay as sublethal effects increased. Our model projected minor (&lt;4%) sublethal effects in adult mussels during the century's five warmest summer temperature regimes, corresponding to 0%–32% declines in recruitment rates. Our research extends the TTL model validation, demonstrates the resilience of subtidal Baltic Mytilus to future extreme heatwaves and offers an approach to predict heatwave‐induced population mortalities, applicable to other species and sensitive systems. Read the free Plain Language Summary for this article on the Journal blog.

Urban form and surface temperature inequality in 683 European cities

Despite rapid urbanization and growing heat stress, comprehensive insights into the association between urban form and environmental inequality are lacking. We study the population-weighted Gini coefficient, the measurement of inequality, of the average land surface temperature (LST) in summer in 683 European cities (i.e. Functional Urban Areas) against thirty-four urban form indicators, i.e. population, area, compact ratio, local climate zones (LCZ), presence of grass, impervious surfaces, trees, water and albedo, elevation, aspect, Köppen-Geiger climate classification (KG) and latitude. We calculate density, Moran's I and Entropy measures to quantify cities' spatial structures and diversity. The area of each city is divided into 1 × 1 km spatial units, and inequality among such units is calculated. Using geographically weighted regression (GWR), we found that the impact of factors varies across the cities and that almost 70 % of overall inequality can be explained by urban form. The variables occasionally decreasing LST inequality were population density and concentration, LCZ 9, dry climate, and high latitude. The ones increasing it were urban size, LCZ 3, 5, 6, 8, entropy LCZ, impervious surfaces' density and concentration, trees, high elevation, aspect southwest, and polar climate. Ultimately, the study discusses the findings and proposes spatial strategies for mitigating inequality.

Some like it hot: Seed thermal threshold variation in obligate seeding Acacia pulchella along a climate gradient

Dormancy in seeds is a key persistence mechanism for many flowering plants. Physically dormant (PY) seeds have water impermeable seed coats, and in fire-prone systems a common mechanism for dormancy release is fire-induced soil heating. However, the thermal thresholds innate to seeds with PY may be influenced by vegetation, climate, and fire regimes, varying substantially between populations of the same species. To investigate intraspecific variation of thermal thresholds in PY seeds, we sampled obligate seeding Acacia pulchella (Fabaceae) which produces PY seeds. Sampling was undertaken from 13 populations across a climate gradient of rainfall and temperature, and between two vegetation communities in fire-prone Mediterranean-type ecosystems of south-west Western Australia. To test a range of weather and fire-induced soil heating dormancy-break scenarios, we conducted dry heat shock experiments between 40 and 140 °C for 10 min and scored germination for 16 weeks. We created population-specific thermal performance curves and extracted the dormancy release temperature at which 50 % of the seeds had germinated (DRT50), the optimum dormancy-breaking temperature to stimulate maximum germination (T0), and the lethal temperature at which 50 % of the seeds were killed (LT50). Generalised linear models were used to examine relationships between thermal thresholds and possible vegetation, climate, and fire regime drivers of intraspecific variation in seed traits. We found that thermal thresholds differed between vegetation communities, with thresholds consistently higher in forest-type ecosystems compared to open woodland, and the influence of climate varied significantly between the two communities. Seeds from Jarrah Forest populations had a DRT50 16.0 °C higher, a T0 9.7 °C higher, and LT50 7.8 °C higher than seeds from Banksia woodlands. A high rate of non-dormancy was identified in one population that had lost fire in its system and displayed significant germination after both summer and fire-related temperatures. The PY thermal thresholds modelled here provide insight into the strong influence of variable soil heating as a function of vegetation and fuel dynamics in fire-prone environments. Our findings highlight the significant intraspecific variation for this species and suggest that fire-induced soil heating generated by vegetation characteristics may be an overlooked element of fire regimes shaping seed traits.

Phenotypic and Gene Expression Analysis of Fruit Development of ‘Rojo Brillante’ and ‘Fuyu’ Persimmon (Diospyros kaki L.) Cultivars in Two Different Locations

Fruit development and maturation rely on intrinsic genetic programs involving hormone biosynthesis and signalling and environmental cues, integrating phenological cycles and climatic issues encompassing abiotic stresses and climate change. In persimmon trees, environmental inputs strongly influence fitness and agricultural performance, and fruit yield can be severely compromised by them. We have grown two persimmon accessions (‘Rojo Brillante’ and ‘Fuyu’) under contrasting meteorological conditions of two locations in Spain and Japan. Fruit size, colour change, and firmness parameters were followed during fruit development from 30 days after fruit set until commercial ripening, and the expression of genes related to ethylene production and signalling, gibberellin response, carotenoid biosynthesis, cell wall dynamics, and oxidative stress were reported. Genes depending on intrinsic developmental programs (ethylene and ripening variables, mostly) showed common expression trends in both cultivars and locations, whereas gibberellin and abiotic stress-related genes mimicked reduced fruit growth and abiotic stress associated with higher summer temperatures (&gt;35 °C) and lower rainfall reported in the Spanish location. The expression pattern of these genes is consistent with a growth–defence trade-off that explains fruit differential growth through hormonal and stress tolerance mechanisms.

Determination of occurrence of atmospheric blockings over the Caspian Sea region in winters of 1959–2022, and influence of them on the ice regime of the Northern Caspian Sea

The ice regime of the Caspian Sea has pronounced influence on the heat and moisture exchange of the reservoir with the atmosphere, the state of the ecosystem, as well as human marine activities, including shipping, fishing, construction of hydraulic structures, etc. Consequently, the development of existing ideas about the causes of changes in the characteristics of the ice regime of such water bodies is actual and socially significant problem of limnology, hydrometeorology, ecology, and navigation. This study was aimed at determination the frequency of occurrence of atmospheric blockings over the Caspian region with standings longer 5 days in winter period of 1959–2022, and investigation of influence of them on the ice regime in the Northern area of the Sea. The following information and data were used: changes in hourly mean values of atmospheric pressure at the sea level, geopotential of isobaric surfaces 850, 500 and 300 hPa, presented in the ERA5 reanalysis; and observational data on air temperature and ice cover from hydrometeorological stations located in the Caspian region of Kazakhstan and Russia. It has been established that in the winter during a long standing of atmospheric blockings the mean daily air temperatures noticeably drop. The values of all the studied characteristics of every atmospheric blocking which occurred in 1959–2022 were estimated as well the influence of them on the ice regime in the North of the Caspian Sea was analyzed. The relationship between a decrease in the frequency of atmospheric blockings (AB), sums of negative air temperatures on its coasts, and the ice cover thickness in the corresponding areas of coastal waters has been revealed in the region. The longer the total AB duration, the lower is the air temperature, and the ice thickness in February is larger.

Single-grain luminescence dating of Manas Lake paleoshorelines reveals late quaternary glacial meltwater forced lake level highstand in arid Central Asia

The spatiotemporal patterns of late Quaternary lake evolution, along with their responses to climatic changes and glacial meltwater in the westerlies-dominated Central Asia, remain unclear primarily due to the lack of well-dated records spanning across glacial and interglacial cycles. In this study, we investigated five well-preserved paleolake shoreline sequences, 15–27 m above the modern lake basin of the now-dry Manas Lake, a representative terminal lake in the Junggar Basin of arid Central Asia. Both single aliquot and single-grain K-feldspar post-infrared infrared stimulated luminescence (pIRIR) dating protocols were applied to 26 shoreline samples to reconstruct a lake level variation for Manas Lake over the past 90 kyr. The reliability of the K-feldspar pIRIR dating was tested through assessment of luminescence characteristics and comparison of single-grain and single-aliquot K-feldspar pIRIR Des. The results indicate that the highest water levels (∼25 m deep) occurred during late Marine Isotope Stage (MIS) 5 (∼80 ka) and MIS 3 (31–27 ka). A lake level 20 m above modern lake basin (a.m.l.b.) occurred from the last deglaciation to the early Holocene (14–10 ka) and again in the late Holocene (3.4–0.3 ka). The lake level changes of Manas Lake are decoupled from observed Westerlies precipitation changes over the past 90 kyr. This decoupling suggests enhanced glacial meltwater sourced from the high Tianshan Mountains, triggered by higher mean summer temperatures, worked together with Westerlies precipitation drove periods of lake level highstand in Manas Lake during late MIS 5, late MIS 3, and early Holocene periods.

Holocene Paleoclimate Changes around Qinghai Lake in the Northeastern Qinghai-Tibet Plateau: Insights from Isotope Geochemistry of Aeolian Sediment

The stable carbon isotope composition of total organic matter (δ13Corg) has been utilized in aeolian sediments, serving as an indicator for reconstructing terrestrial paleoenvironments. The Qinghai Lake (QHL) Basin is a climate-sensitive region of significant importance in paleoclimatic reconstruction. However, the reconstructed climatic variations based on δ13Corg in aeolian sediments in the QHL Basin in the northeastern Qinghai-Tibet Plateau (QTP) are lacking, and their paleoclimatic significance remains poorly understood. By conducting δ13Corg measurements on the Niaodao (ND) aeolian profile near QHL, we reconstructed the paleoclimate changes of 11 ka–present. The variation range of the δ13Corg values in the ND profile indicated the terrestrial ecosystems were not the sole contributor to lacustrine organic matter. The δ13Corg values are an indicator of historical temperature changes in the study area, exhibiting similar trends with the reconstruction of Chinese summer temperatures, East Asian air temperature, global temperature, and Northern Hemisphere summer insolation at 37° N. The temperature increased with high frequency and amplitude oscillations, with strong aeolian activity and low total organic carbon accumulation during the Early Holocene. The temperature was maintained at a high and stable level, with the weakest aeolian activity and intensified pedogenesis during the Middle Holocene. The temperature decreased at a high rate, with renewed aeolian activity and weak pedogenesis during the Late Holocene.

Temperature and palaeolake evolution during a Middle Pleistocene interglacial–glacial transition at the Palaeolithic locality of Schöningen, Germany

The Middle Pleistocene Reinsdorf sequence at the Lower Palaeolithic sites of Schöningen offers the opportunity to reconstruct a rarely well‐preserved post‐Holsteinian environmental transition from an interglacial into a glacial phase along with its highly dynamic interjacent climatic oscillations. Combining biological proxies, element composition and stable isotope ratios of two lakeshore sequences at excavation site 13 II, we demonstrate repeated variations in climate, hydrology and catchment vegetation cover. New ostracod‐based quantitative mean summer and winter air temperature reconstructions with the Mutual Ostracod Temperature Range (MOTR) method provide the first detailed information about the temperature evolution. The interglacial temperature maximum, probably corresponding to Marine Isotope Stage 9e, is followed by a first dry phase and, during the younger part of the Reinsdorf sequence, by a second dry period. Both were marked by lower precipitation/evaporation ratios, reduced vegetation cover in the catchment and increased surface inflows from springs. Temperature reconstructions of these two steppe (open woodland) phases yield very narrow ranges for mean January (−4–0 °C) and July (+17–19 or +17–21 °C) air temperatures, demonstrating that, while summers were similar to those of today, winters were at least 1 °C colder, hinting at a more pronounced continental climate. Precise temperature estimates for the interjacent woodland and steppe (woodland) phase are hindered by generally wider ranges produced by the MOTR method (January mean −4–3 °C, July mean +15–21 °C). The development of a more extensive vegetation cover, reducing surface runoff and erosion in favour of increased river and groundwater discharge, as indicated by a shift in microfossil and stable isotope records, suggests generally more humid climates with higher precipitation/evaporation ratios as well as reduced seasonal temperature variations.