Annual Summer Research Articles

Temperature effects on the impact of two invasive parasitic copepods on the survival, growth, condition, and reproduction of native mussels

An increase in temperature due to climate change may affect the geographic ranges of invasive parasites and alter their impact on native hosts. Our goal was to determine if the effects of infection by two species of invasive endoparasitic copepods on native blue mussel hosts (Mytilus edulis) change with increasing temperatures. We investigated this with a laboratory experiment using temperatures that represent annual mean and mean summer water temperatures of past observations and future predictions for the study area, the European Wadden Sea (10–26 °C). Over a period of 8–20 weeks, infection with Mytilicola intestinalis lowered mussel condition and infection with Mytilicola orientalis decreased mussel shell growth. High temperatures decreased mussel growth and condition in general, but only at low temperatures (10–14 °C) the parasite-induced loss of condition was evident compared to uninfected mussels. Mussel mortality and reproductive activity were not affected by parasite infection, although both were impacted by temperature: the highest temperature (26 °C) increased mussel mortality, and gamete ripening only occurred at lower temperatures (10–18 °C). Taken together, these results suggest that both infection and high temperatures have independent negative effects. However, an increase in temperature does not worsen the effect of infection on individual mussel hosts, and neither does infection decrease host tolerance for long-term exposure to high temperatures. These findings add to our understanding of the interplay between increasing temperature and the interaction between invasive parasites and native hosts, and help predicting host and parasite dynamics in systems affected by species invasions and climate change.

Building Resilience in Rural STEM Teachers Through a Noyce Professional Learning Community

Addressing the critical STEM teachers’ shortage in the rural United States requires not only recruiting new teachers but also improving retention and teacher resiliency. This study explores contextual protective factors through the Early Career Teacher Resilience (ECTR) framework. The major objective of this study was to evaluate the impacts of the NSF Noyce Professional Learning Community (PLC) on rural STEM teacher resilience. Key components of the Noyce PLC included scholarship support, pre-service mentoring, attendance at local and regional educational events, active engagement in the program’s annual summer conference, and participation in a closed Facebook group. We developed an ECTR framework-based online instrument with 28 questions and sent it to 311 university alumni, including 44 Noyce alumni. The results suggest that the Noyce PLC has excelled in fostering collaborative learning environments, providing resources that enhance teaching and learning, accommodating new and different ways of thinking, and supporting teachers’ professional growth beyond graduation. The findings underscore the importance of integrating theoretical and practical knowledge, supporting ongoing professional learning, and building strong professional relationships. Several aspects of the Noyce PLC could be replicated in other STEM teacher preparation programs to enhance teacher resilience, effectiveness, and career development.

The Survival of Arctic Sea Ice May Depend on Its Travel Routes

Researchers find that the motions of ice parcels determine which ones survive the annual summer melt.

Climatic Trends and Local Perception in Nechasalyan Rural Municipality: A Climate Change Scenario

Climatic policy responses are influenced by how communities and individuals perceive and understand climate variabilities and changes. Integrating community perceptions with observed climate data can provide valuable information to support policies to reduce climate-related risks and enhance climate change adaptation. This study examines climate change in the Nechasalyan Rural Municipality of Solukhumbu district, Nepal, through an integrated analysis of meteorological data and local people's perceptions. Temperature and rainfall data for 31 years i.e. 1991-2021 were collected and analyzed from nearest Meteorological station (Okhaldhunga Station). Local peoples’ perceptions were gathered from the household survey (n=70) along with key informant interview (n= 10) and focus group discussion (n= 5). The analysis revealed that the average maximum, winter and summer temperature trends seemed to be increasing where average minimum trend was decreasing of which only average winter temperature was significant (p<0.05). Despite insignificance in the increases in average annual maximum and summer temperatures, they pose potential challenges in the long run. Similarly, the average annual rainfall as well as seasonal rainfall trends seemed to be decreasing, and only average July rainfall trend was statistically significant (p<0.05). The results indicate that while local perceptions about the changes in the temperature were consistent, there was disconnection between these perceptions and observed rainfall trends. The consistency between local perceptions and rising temperature trends suggests that people remember temperature changes more vividly than rainfall patterns, warranting future research to investigate the causes of disparities between local perceptions and observed climate trends. Additionally, exploring effective communication strategies to bridge the gap between scientific findings and local understanding could enhance community climate resilience.

The impact of extreme weather events of projected Canadian regional climate model data on flexible pavement

This paper presents findings about the influence of projected data from the Canadian regional climate model on the performance of flexible pavement, building upon the results from previous work where the data were generated and published, in which a general trend of decreasing the design life was observed. Projected temperature is the most important extreme climate impact on flexible roads. Adopting a conservative approach demonstrated that two extreme events of maximum mean annual air temperature and maximum summer average air temperature resulted in significant reduction of 25 years road design life. The observed trend indicates a severity range of 7%–15% in terms of design service life loss when considering events every year compared to every 5 years. The findings revealed a reduction in pavement design life by 34%, 50%, 73%, and 90% for historical, short, intermediate, and long-term life cycles in the city of Windsor, respectively.

Impact and evaluation report of the DTA3/COFUND programme

Background This report evaluates the outcomes and effectiveness of the DTA3/COFUND doctoral fellowship programme, which ran from 2019 to 2023. Funded by the Horizon 2020 Marie Skłodowska-Curie PhD Fellowship programme, DTA3 aimed to foster interdisciplinary, international, and industry-focused research across 15 UK universities. Methods The programme supported 71 international fellows from diverse countries, emphasising inter-sectoral skills and post-doctorate employability. A mixed-methods study design was employed, involving online surveys, focus groups, and interviews with fellows, supervisors, and university programme leads. Results Key areas of evaluation included research activities, employment outcomes, wellbeing, doctoral training experiences, and institutional impact. The data revealed that 72% of fellows had submitted their PhD theses, with 66% having completed their viva by the report's conclusion. The programme also recorded a high employment rate, with 55% of fellows in the final stages of their PhD already employed. The DTA3 programme featured an enhanced training component, including annual summer schools, spring refresh events, autumn schools, and residential writing retreats. These events focused on enhancing employability, academic skills, research impact, and intersectoral collaboration. Despite challenges such as visa complications, COVID-19 restrictions, and international supervisor movements, the programme maintained a strong completion rate. Conclusions The report highlights the programme's success in providing fellows with significant international mobility opportunities, with many securing employment in their home countries or abroad shortly after completing their PhD. The DTA3 legacy includes ongoing cohort tracking, an alum network, and a dedicated legacy fund to support further international collaboration and knowledge exchange. Overall, the DTA3/COFUND programme demonstrated substantial impact in training and developing skilled researchers, promoting international collaboration, and enhancing employability in diverse sectors, thereby contributing positively to the global research community.

Integrated farming optimization ensures high-yield crop production with decreased nitrogen leaching and improved soil fertility: The findings from a 12-year experimental study

Context or problemSustainable farming practices, including precision fertilization, water-saving irrigation and recycling of organic materials, have been implemented worldwide in recent decades to achieve high crop yields and minimize nonpoint source pollution. However, the comprehensive impacts of these agricultural practices have seldom been systematically evaluated in field production. As agricultural intensification started in the 1980s, most previous studies focused on a single practice in the context of low land productivity. Objective or research questionThe objective of this research is to investigate and evaluate how holistic farming practices affect both crop production and environmental quality. MethodsWe reported findings from a 12-year experiment (2008–2020) in the highly intensive North China Plain (NCP) farming region, and conventional and optimized farming measures were compared. Three field treatments with annual double cropping (winter wheat (Triticum aestivum L.) and summer maize (Zea mays L.)) were chosen in the study, i.e., control without nitrogen (N) application (CK), farmers’ conventional practices (CON), and optimized practices (OPT), were chosen for this study. ResultsCompared with the CON treatment, OPT reduced N fertilizer input by 41.4 % and irrigation water by 27.1 % but produced similar grain yields; OPT increased the N recovery efficiency (REN) and N utilization efficiency (NUT2E) by 90.4 % and 53.0 %, respectively; these values were much greater than the increases in REN (+56.1 %) and NUT2E (+25.5 %) when soil N change was not considered. Similarly, compared with those in the CON treatment, the soil N stock (0–60 cm) in the OPT treatment increased by 8.4 %, and the N loss via leaching, ammonia volatilization and N2O + NO + N2 decreased by 47.1 %, 11.4 % and 28.6 %, respectively. ConclusionsOur study revealed that the integration of optimized practices of organic material recycling, precision fertilization and water-saving irrigation substantially reduced N losses, mainly through decreased N leaching, but maintained fertilizer N in the root-zone soil layer, which is important for a sustainable and high-yield crop production. Implications or significancesThe dissemination of these optimized practices to other regions in China and beyond will be highly important for achieving the dual goals of food security and environmental protection.

Professional development is the key to securing a future rheumatology workforce. Long term evaluation of a summer school for medical students-a national scientific society's educational initiative.

A cumulative imbalance between rheumatologic need and an inadequate number of young colleagues entering the field leads to a dearth of rheumatologists in the near future. The Austrian Society for Rheumatology and Rehabilitation (ÖGR) has been organizing an annual Rheumatology Summer School (RSS) for medical students since 2017. The aim of this study was to analyze the annual RSS evaluations, the RSS' overall effects on attracting new talent into the field and the lasting promotion of rheumatology. A questionnaire was distributed immediately after each RSS meeting. Additionally, we conducted an electronic survey among RSS participants (2017-2022) to assess their career development trajectories. From 2017-2023, a total of 220 students attended the RSS. They all completed the annual evaluation. Accordingly, students' expectations were met in 80% (2017) to 97% (2023) of cases. The electronic survey was completed by 64/133 (48%) students; 49 (77%) indicated that the RSS had markedly increased their desire to specialize in rheumatology. Among the 36 graduates, 10 (28%) had already been working in the field of rheumatology and 6 (17%) were considering this specialty but had not decided yet. RSS attendees in their 6th study year were influenced to a greater extent by the RSS to choose rheumatology as their primary specialty than 4th or 5th year students. The participants indicated that they benefited most from the RSS in terms of knowledge gain, personal awareness of rheumatology, networking among fellow students as well as gaining access to RSS faculty. The RSS enhanced students' intention to choose rheumatology, particularly in those close to graduation, and led to increased awareness and deeper knowledge about rheumatology.

Field Notes from the SITI Summer Workshop

From 1992 until 2021, SITI Company held an annual summer workshop at Skidmore College in Saratoga Springs, New York. In 2012 and 2013, four artists documented their daily experiences at the workshop on social media to share with artists they had met at a Winter Training session in the city earlier that year. From these memories comes an archival script that offers insight into SITI’s pedagogical models and the variety of ways students experienced SITI training.

Unraveling boreal forest composition and drivers across scales in eastern Siberia

The Siberian boreal forest is the largest continuous forest region on Earth and plays a crucial role in regulating global climate. However, the distribution and environmental processes behind this ecosystem are still not well understood. Here, we first develop Sentinel-2-based classified maps to show forest-type distribution in five regions along a southwest-northeast transect in eastern Siberia. Then, we constrain the environmental factors of the forest-type distribution based on a multivariate analysis of bioclimatic variables, topography, and ground-surface temperatur at the local and regional scales. Furthermore, we identify potential versus realized forest-type niches and their applicability to other sites. Our results show that mean annual temperature and mean summer and winter temperatures are the most influential predictors of forest-type distribution. Furthermore, we show that topography, specifically slope, provides an additional but smaller impact at the local scale. We find that the filling of climatic environmental niches by forest types decreases with geographic distance, but that the filling of topographic niches varies from one site to another. Our findings suggest that boreal forests in eastern Siberia are driven by current climate and topographical factors, but that there remains a portion of the variability that cannot be fully accounted for by these factors alone. While we hypothesize that this unexplained variance may be linked to legacies of the Late Glacial, further evidence is needed to substantiate this claim. Such results are crucial to understanding and predicting the response of boreal forests to ongoing climate change and rising temperatures.

Key determinants of soil labile nitrogen changes under climate change in the Arctic: A meta-analysis of the responses of soil labile nitrogen pools to experimental warming and snow addition

The Arctic terrestrial ecosystems are undergoing rapid climate change, causing shifts in the dynamics of soil nitrogen (N), a pivotal but relatively underexplored component. To understand the impacts of climate change on soil labile N pools, we performed meta- and decision-tree analyses of 391 observations from 38 peer-reviewed publications across the Arctic, focusing on experimental warming and snow addition. Soil dissolved organic nitrogen (DON), ammonium (NH4+), and nitrate (NO3-) pools under experimental warming exhibited overall standard mean differences (SMDs) ranging from −0.08 to 0.02, with no significance (P > 0.05); however, specific conditions led to significant changes. The key determinants of soil labile N responses to warming were experimental duration and mean annual summer temperature for DON; annual precipitation, soil moisture, and sampling timing for NH4+; and soil layer for NO3-. Snow addition significantly increased all labile N pools (overall SMD = 0.23–0.36; P < 0.05), influenced by factors such as sampling timing and vegetation type for DON; experimental duration and soil moisture for NH4+; and soil pH for NO3-. By consolidating and reprocessing datasets, we not only showed the overall responses of soil labile N pools to climate manipulation experiments in Arctic tundra ecosystems but also identified key determinants for changes in soil N pools among environmental and experimental variables. Our findings demonstrate that warming and snow-cover changes significantly affect soil labile N pools, highlighting how the unique environmental characteristics of different sites influence terrestrial N cycling and underscoring the complexity of Arctic N dynamics under climate change.

On the Variability in the Temporal Stability Pattern of Soil Moisture Under Mediterranean Conditions

In recent decades, there has been increasing interest in studying the variability in soil water properties and, specifically, the spatiotemporal variability in the soil water content. This is motivated by the notable theoretical and applied research interests in soil moisture dynamics and their implications for many natural processes. This study aimed to study whether there are variations in the spatial pattern of the temporal stability of soil moisture over time and to analyze the possible influences of certain hydroclimatic (soil water content, precipitation, and evapotranspiration) and soil factors (texture, bulk density, and organic matter content) on these variations. This study was conducted within the Soil Moisture Measurement Stations Network of the University of Salamanca (REMEDHUS, Spain) under Mediterranean conditions, with daily surface moisture data (0–5 cm depth) obtained from 20 stations for the 2006-2023 period. The results showed differences between the average pattern obtained with the 18-year data series and that obtained with the data series for each year. In more than half of the years studied, the representative station differed from that derived from the average pattern. The mean annual precipitation and summer precipitation characteristics seem to be the main factors influencing the variability in the spatial pattern of the temporal stability of soil moisture.

Multiproxy studies on the spatially distinct surface samples to reconstruct palaeoecology and palaeoclimate from the Core Monsoon Zone of India

Palaeoclimatic reconstructions necessitate an understanding of the various biotic and abiotic responses to develop a modern analogue. The interpretation and calibration of the modern data allow us to check the lead-lag effect in different proxy parameters, which could be applied for robust palaeoclimatic reconstructions. We, in the present study, analysed pollen and diatom (biotic proxies), as well as grain size, magnetic susceptibility and geochemistry (abiotic components) of the modern soil samples, collected from the states of Madhya Pradesh and Chhattisgarh, the Core of the Monsoon Zone (CMZ) in central India. The weathered materials of the Palaeocene Cretaceous extrusive rocks and sedimentary rocks of the Late Triassic to the Upper Carboniferous are underlying the soil cover in these areas, respectively. The study revealed that the overall pollen and diatom preservation is comparatively good in the areas where the Palaeocene Cretaceous extrusive rocks are found except for the areas of human settlements, whereas the preservation of pollen and diatom was comparatively poor in areas where sedimentary rocks of the Late Triassic to Upper Carboniferous are found. The most plausible reason for this difference is the availability of nutrients which are supplied more abundantly by the easily weatherable Deccan basalt rocks compared to their sedimentary counterparts. The present study will serve as baseline information about biotic-abiotic interactions operating in the central Indian Core Monsoon Zone (CMZ). Since the intensity and duration of the rainfall in the CMZ are largely governed by the annual Indian summer monsoon rainfall (AISMR), therefore, the present study could help trace the weak or intense monsoon periods (break and active spells, respectively) of the past hundreds to thousands of years by studying the sediment profiles/cores.

A regressive analysis of the main environmental risk factors of human echinococcosis in 370 counties in China.

Echinococcosis is a natural focal, highly prevalent disease in China. Factors influencing the spread of echinococcosis are not only related to personal exposure but also closely related to the environment itself. The purpose of this study was to explore the influence of environmental factors on the prevalence of human echinococcosis and to provide a reference for prevention and control of echinococcosis in the future. Data were collected from 370 endemic counties in China in 2018. By downloading Modis, DEM and other remote-sensing images in 2018. Data on environmental factors, i.e., elevation, land surface temperature (LST) and normalized difference vegetation index (NDVI) were collected. Rank correlation analysis was conducted between each environmental factor and the prevalence of echinococcosis at the county level. Negative binomial regression was used to analyze the impact of environmental factors on the prevalence of human echinococcosis at the county level. According to rank correlation analysis, the prevalence of human echinococcosis in each county was positively correlated with elevation, negatively correlated with LST, and negatively correlated with NDVI in May, June and July. Negative binomial regression showed that the prevalence of human echinococcosis was negatively correlated with annual LST and summer NDVI, and positively correlated with average elevation and dog infection rate. The prevalence of human cystic echinococcosis was inversely correlated with the annual average LST, and positively correlated with both the average elevation and the prevalence rate of domestic animals. The prevalence of human alveolar echinococcosis was positively correlated with both NDVI in autumn and average elevation, and negatively correlated with NDVI in winter. The prevalence of echinococcosis in the population is affected by environmental factors. Environmental risk assessment and prediction can be conducted in order to rationally allocate health resources and improve both prevention and control efficiency of echinococcosis.

Subsurface evolution of three types of surface marine heatwaves over the East Sea (Japan Sea)

Extremely high seawater temperatures (beyond the 90th percentile threshold) are a key characteristic of marine heatwaves (MHWs), which adversely affect human and marine ecosystems. It is important to characterize the MHWs in the East Sea (Japan Sea), a semi-enclosed deep basin connected to the outside seas/ocean by shallow and narrow straits, where the most rapid upper ocean warming has been reported in recent decades. Despite several reports on their rising frequency and severity, the characteristics, and underlying dynamics of East Sea MHWs (ESMHWs), particularly their subsurface evolution, remain poorly understood. In this study, we aimed to understand the subsurface evolution patterns of ESMHWs and the underlying mechanisms. Here, summer (June, July, and August) ESMHWs from four ocean reanalysis products were characterized after being verified against those from long-term (2000–2015) time-series observations near the east coast of Korea. We found the HYCOM reanalysis products is the best match with the observation, showing consistent evolution patterns with the ESMHWs in the observation, yielding high correlation coefficients (ranging from 0.7 to 0.9 at the surface), and low root-mean-square errors (3°C). Therefore, the HYCOM reanalysis is further used to characterize the subsurface evolution of surface ESMHWs. A rising frequency of annual mean and summer ESMHWs across the whole East Sea, with a maximum increasing rate of 1–2 events in 40 years and mean cumulative intensity of 5–9°C days decade-1. Three types (Types-A, -B, and -C) of subsurface evolution of ESMHW were commonly found in six sub-regions (where the increasing ESMHWs trends are maximum)—three in the western and three in the eastern parts. The three types are Type-A, which is surface-confined and short-lived with anomalous warm surface temperatures and cold subsurface temperatures; Type-B, characterized by warm anomalies propagating from the surface to the upper several meters with no subsurface cold anomalies; and Type-C, exhibiting anomalous warm temperatures at the upper 200 m. Although increased shortwave radiation, decreased wind speed, and thinned mixed layer commonly contribute to the formation of all three types, the relative role of the heat penetration into the layer below the mixed layer and dissipation mechanisms significantly differ among the types. Common ESMHW evolution features include mixed layer deepening, heat release to the atmosphere, and interactions between the surface mixed layer and deeper layers, while horizontal advection played a significant role only during the Type-C ESMHW events. The long-term trends in frequency, cumulative intensity, and duration of ESMHWs were discussed in terms of those in each type ESMHWs metrics along with long-term surface warming, subsurface cooling, and weakening currents in the six sub-regions. This study provides significant insights into surface and subsurface evolution of MHWs in this and other marginal seas in warming climate conditions.

Abstract WP262: Enhancing Stroke Knowledge Among Youth: Insights from Stroke Busters

Introduction: Educating youth about stroke can improve stroke knowledge in communities. Stroke Buster s, a 5-day program for high school students, consists of interactive stroke lectures, a mock stroke code simulation, and a hands-on thrombectomy demonstration. In 2022, we found that the program was efficacious in improving stroke knowledge using pre/post-tests. In 2023 we designed a consolidated 1-day program, and also repeated the annual 5-day summer program. We assessed pre/post-test knowledge for each workshop, long-term retention, and if teaching the program improved knowledge for prior participants. The optimal duration and format of stroke education for youth is not known. Methods: Students from three cohorts of the Yale University Pathways to Science program participated in Stroke Busters: 13 students from Summer 2022 (5-day, 90 min/day), 14 from Spring 2023 (1-day, 90 min), and 15 from Summer 2023 (5-day, 90 min/day). Student demographics of the overall Pathways to Science program were 31% White, 29% Black, 28% Hispanic, 12% Asian and &lt;1% other. 8-question pre/post tests were administered at the beginning and conclusion of each session, as well as 8 months following the summer 2022 program. Results: Scores were similar for both summer (5-day) programs, increasing from 36.3% (pre-test) to 66.3% (post-test) in 2022 and from 41.7% to 62.5% in 2023. For the 1-day program, the scores increased from 35.7% to 62.5%. Post-test scores were similar for both the 5-day program and the 1-day consolidated program. Five students from the 2022 summer program replied to the 8-month follow up survey, resulting in an average test score of 65%, which was similar to their immediate post-test score of 66.3%. Two students from Summer 2022 (5-day) returned to teach the Spring 2023 (1-day) program, and their average test score after teaching was 87.5%. Conclusion: Stroke Busters is efficacious in promoting long-term retention of stroke knowledge among high school students; students who taught the course retain knowledge even better. The equivalence of post-test scores between the 5-day and 1-day programs offers valuable insights for resource optimization without compromising education quality.

The effect of intentional summer flooding for mosquito control on the nitrogen dynamics of impounded Avicennia germinans mangrove forests

Coastal wetlands such as mangrove forests are breeding grounds for nuisance-causing insects. Rotational Impoundment Management (RIM) for mosquito control involves annual summer inundation of impounded mangrove forests with estuarine water during the summer half year. However, in addition to controlling mosquitos, RIM may change biogeochemical pathways. This study set out to investigate how RIM quantitatively affects physicochemical soil characteristics and potential nitrifying and denitrifying activities (PNA and PDA), which are key in the global nitrogen cycle. Before and after the implementation of RIM, soil samples were collected annually in habitats differing in size and abundance of black mangroves (Avicennia germinans) in an impoundment with RIM and in an adjacent impoundment with a more open connection to the lagoon. Compared to the non-managed impoundment, soil moisture content, total nitrogen and PDA increased, while salinity decreased after the start of annual summer flooding, but only in the dwarf habitat. In the sparse and dense habitats, total nitrogen and PDA increased independently of summer flooding, whereas soil moisture content and salinity were not affected by RIM. Labile organic nitrogen increased only in the RIM impoundment, irrespective of the habitat type. PNA was generally not affected with time, except in the dwarf habitat in the absence of intentional summer flooding where it increased. Changes in the non-managed impoundment adjacent to the RIM impoundment demonstrate the importance of groundwater exchange in linked ecosystems. The consequences of interventions in the management of mangrove impoundments and adjacent forests for the nitrogen budget are discussed.

Sobressemeadura de pastos anuais de verão na cultura da soja para suprir a escassez de foragem outonal

ABSTRACT: In integrated crop-livestock systems, overseeding annual summer pastures over grain crops can reduce forage shortages in autumn without altering grain production. This study evaluated the influence of pearl millet (Pennisetumglaucum L.) and sudangrass (Sorghum Sudanese) overseeded on a soybean (Glycine Max) crop or no-tillage seeding after soybean harvest on productive aspects of pasture. The experimental design was a randomized block with treatments in a 2 × 2 factorial arrangement (pearl millet or sudangrass, overseeding in the full seed stage (R6) of soybean crops or seeding them in a no-tillage system after soybean harvest) in two agricultural years. Pasture height, plant stand, tiller density, and forage production were higher in the first crop year. The overseeding strategy resulted in higher pasture height and foraged production in the first crop year and higher pasture utilization for the next two crop years. Under the no-tillage strategy, the plants stand more elevated in the first crop year, resulting in a higher tiller density in the second crop year. Pasture height, utilization period, and forage production did not differ among the forage species. Pearl millet had a more elevated plant stand, while sudangrass had a higher tiller density. Annual summer pasture overseeding of soybean crops increases the pasture utilization period and forage production in autumn.

Reconstruction of temperature and monsoon precipitation in southwestern China since the last deglaciation

Monsoon precipitation and temperature are the crucial components of the Indian monsoon climate, yet their spatial-temporal relationship remains unclear. In this study, we reconstruct the changes in monsoon precipitation and mean annual temperature simultaneously over the past 16,000 years using multiple proxies, including isoprenoid glycerol dialkyl glycerol tetraethers (isoGDGTs) and n-alkanes, from an alpine lake in southwestern China. On the one hand, the reconstructed monsoon precipitation shows a long-term increasing trend during the last deglaciation and a gradual decrease during the Holocene, with the highest-humidity period occurring in the early Holocene. Our result displays good consistency with the changes in regional mean annual precipitation, summer precipitation, and monsoon intensity during the last deglaciation and the Holocene. On the other hand, the reconstructed mean annual temperature inferred from the n-alkane proxy shows a long-term warm trend since the last deglaciation. Our result is consistent with the regional reconstruction of both mean annual and summer temperatures during the last deglaciation, while evident seasonal differences were observed for Holocene records with a cooling trend of summer temperature and a warm trend of mean annual temperature. Comprehensive comparison reveals that monsoon precipitation in the Indian monsoon region is mainly related to changes in the Intertropical Convergence Zone (ITCZ) and land-sea thermal contrast controlled by boreal summer insolation. In addition, the increase in temperature during deglaciation is primarily attributed to the escalation of greenhouse gases (GHGs), while the divergent trend of seasonal temperature during the Holocene is mainly attributed to the changes in local seasonal insolation. Our research emphasizes that monsoon precipitation is a summer signature in the Indian monsoon region, which is consistent with the changes in summer temperature, while contrasting with the changes in mean annual temperature. Therefore, it is necessary to consider the seasonal difference in temperature changes when investigating the hydrothermal combination in Indian monsoon regions.

Snow Persistence and Snow Line Elevation Trends in a Snowmelt-Driven Basin in the Central Andes and Their Correlations with Hydroclimatic Variables

The mountain cryosphere is crucial for socio-economic processes, especially during the dry seasons. However, anthropogenic climate change has had a detrimental impact on the cryosphere due to its sensitivity. Over the past two decades, there has been a decline in precipitation and a temperature rise, leading to a substantial reduction in the timing and extent of snow cover. This increase in temperature also elevates the snow line elevation (SLE), further diminishing the volume of available freshwater in the snow-driven basins of the Andes. In this study, we use 22 years (2000–2021) of 8-day snow product (MOD10A2) from the Moderate Resolution Imaging Spectroradiometer (MODIS) to analyze the annual and seasonal variability of snow cover area, SLE, and snow persistence (SP, an indicator of the duration of snow) in the Yeso River basin in Central Chile and the correlation of SP and SLE with hydrometeorological variables and climatic indices. We introduce a new approach called the Maximum Dissimilarity Method to obtain the SLE even on cloudy days. The results are as follows: (1) Snow cover area reductions of 34.0 km2 at low elevations in spring and 86.5 km2 at mid elevations in summer were found when comparing the period 2016–2021 to 2000–2004; (2) SP trends at the annual scale revealed a significant decrease in 89% of its area and an average of 3.6 fewer days of snow cover per year; (3) an upward and significant trend of 21 m‧year−1 in the annual SLE was found; and (4) annual SP and SLE were highly correlated with annual hydrometeorological variables, and spring and summer snow variables were significantly correlated with dry streamflow. This methodology can potentially serve as a valuable tool for detecting trends in snow-covered surfaces, and thereby associate these changes with climate change or other anthropogenic effects in future research.