Climate Interactions Research Articles

A hybrid framework for short-term irrigation demand forecasting

Reliable short-term forecasts of Irrigation Water Demand (IWD) can provide useful information to help water supply system operators with day-to-day operating decisions. Forecasting IWD is a complex task due to different natural (soil, water, crop, and climate interactions) and behavioral (farmers’ decision-making) components of the irrigation process. So far, various approaches have been developed to estimate IWD values in different contexts. One common approach is the application of data-driven methods to map the relationship between the main influential factors and IWD. Data-driven approaches often do not consider any conceptual understanding of the system in modeling IWD, which has been found to be effective in improving the predictive performance when considered. In this study, a hybrid framework has been introduced and developed by incorporating existing physical knowledge of the system into a data-driven model to predict IWD. This framework consists of two modules: In the first module, a simple conceptual approach was implemented to model the understood factors leading to crop water needs using observation data. In the second module, a data-driven model was used to capture the remaining relationships between inputs and the output in the irrigation process. The proposed hybrid framework was then applied to estimate daily IWD up to 7 days ahead for an irrigation district in Victoria, Australia. Results show that the integration of physical system understanding into data-driven models can improve the performance of IWD forecasting models, particularly during the high-demand period. In addition, the hybrid framework provides improved system understanding and thus leads to increased capacity to support operational decisions.

Editorial: Applications of Remote Sensing in Glaciology

Contemporary and significant spatiotemporal changes in glaciers are a result of rapidly evolving regional and global climate, and continuous monitoring is imperative for understanding the complexities of glacio–climatic interactions [...]

The influence of soil development on the depth distribution and structure of soil microbial communities

Although it has been shown that the interaction of climate and time shape the dynamics of soil organic matter (SOM) storage and preservation in soil, the role of soil microbial communities in this dynamic remains unclear. Microbial communities are present throughout soil profiles and likely play critical roles in SOM and nutrient cycling, however the influence of other factors such as soil development (i.e., age) and the composition SOM on microbial community variation with depth has yet to be quantified. Improving our understanding of the relationship between soil development, soil depth, and microbial communities may provide insight to the critical role they play in cycling and preservation of SOM, as well as more mechanistic predictions of the response of soil communities to change, such as landscape-scale changes in available moisture or temperature regimes. Here we compare soils spanning a soil age by climate gradient (i.e., climo-chronosequence) to better understand the mechanisms which influence soil microbial community structure and the molecular composition of SOM. While we observed little depth-dependence in metrics of microbial community structure (i.e., composition, diversity, dissimilarity) across the range of soil development under a wetter climate, we found significant depth-dependent changes in community metrics under a drier climate, which became more pronounced as soils became older. This shift in bacterial and archaeal community structure and diversity is most apparent below a clay-rich argillic horizon formed in the older, drier soils. The molecular composition of SOM as measured by high resolution mass spectrometry (i.e., FTICR MS) also exhibited similar shifts in composition with soil depth and age. Our results highlight how soil moisture shapes the interaction of soil development, SOM, and microbial community composition. Differences in the moisture regime between our two study sites drive differences in biogeochemical depth gradients and subsequent variation in soil microbes and SOM. This suggests that knowledge of not just the pedogenic trajectory of soil development, but also the spatial position relative to distinct pedogenic features, are important for explaining variations in the depth-dependencies of microbial communities and associated SOM.

Warming Trend and Cloud Responses over the Indochina Peninsula during Monsoon Transition

An exacerbated precipitation–temperature relationship can lead to compound extremes. The role of clouds in such a relationship is relatively uncertain. Here, we investigate the cloud–precipitation–temperature relationships over the Indochina Peninsula during the summer monsoon transition. The negative correlation between cloudiness/precipitation and surface maximum temperature is valid on seasonal and interannual timescales. The near-surface temperature exhibits interdecadal variability and a long-term warming trend. The warming trend has accelerated in the past two decades. In the anomalous warm years, the remarkably strong western Pacific subtropical high inhibits the development of clouds, especially the middle and high cloud-top regimes, leading to the suppression of deep convection and precipitation. There are more optically thin (moderate to thick) clouds with smaller (larger) effective radii in the high cloud-top regime for the warm (cold) years. The dominance of shallow cumulus is a distinct feature in the warm years. The daytime heating of enhanced surface insolation due to decreased cloudiness is worsened by the dry condition of the precipitation deficit. The water vapor warming effect can prevent an efficient drop in nighttime temperature, thereby exacerbating the warm condition under the warming trend. The cloud–precipitation–temperature relationships coupling with the monsoon development can be used to diagnose the regional scale cloud–climate interactions in climate models.

No-Till Soil Organic Carbon Sequestration Patterns as Affected by Climate and Soil Erosion in the Arable Land of Mediterranean Europe

No-tillage (NT) has been considered an agronomic tool to sequester soil organic carbon (SOC) and match the 4p1000 initiative requirements of conservative soil management. Recently, some doubts have emerged about the NT effect on SOC sequestration, often because observations and experimental data vary widely depending on climate and geographic characteristics. Therefore, a suitable SOC accounting method is needed that considers climate and morphology interactions. In this study, the yearly ratio between SOC in NT and conventional tillage (CT) (RRNT/CT) collected in a previous study for flat (96 samples) and sloping (44 samples) paired sites was used to map the overestimation of SOC sequestration. It was assumed that there would be an overestimation of NT capacity in sloping fields due to lower erosion processes with respect to CT. Towards this aim, Geographical Information System (GIS) techniques and an extensive input database of high spatial resolution maps were used in a simplified procedure to assess the overestimation of SOC stocks due to the sloping conditions and spatial variability of the Aridity Index (AI). Moreover, this also made it possible to quantify the effects of adopting NT practices on soil carbon sequestration compared to CT practices. The method was applied to the arable lands of five Mediterranean countries (France, Greece, Italy, Portugal and Spain) ranging between the 35° and 46° latitude. The results showed an overestimation of SOC sequestration, when the AI and soil erosion were considered. The average overestimation rate in the studied Mediterranean areas was 0.11 Mg ha−1 yr−1. Carbon stock overestimation ranged from 34 to 1417 Gg for Portugal and Italy, respectively. Even if overestimation is considered, 4p1000 goals are often reached, especially in the more arid areas. The findings of this research allowed us to map the areas suitable to meet the 4p1000 that could be achieved by adopting conservative practices such as NT.

The effects of crowding and service climate on the perception of the Experiential value of consumption in self-service restaurants

ABSTRACT This research seeks to verify whether perceived crowding, perceived service climate, positive customer-to-customer (C2C) interactions, and dysfunctional customer behavior influence the perception of experiential consumption value in self-service restaurants. We surveyed by applying a questionnaire to 337 consumers. The results showed that the perceived service climate and positive C2C interactions could influence the experiential value of consumption in a self-service restaurant. We found that perceived crowding can influence positive C2C interactions and dysfunctional customer behavior. The results also demonstrate that positive C2C interactions can mediate the relationship between the perceived service climate and the experiential value of consumption.

Climate, Land, Energy and Water systems interactions – From key concepts to model implementation with OSeMOSYS

The Climate, Land, Energy and Water systems (CLEWs) approach guides the development of integrated assessments. The approach includes an analytical component that can be performed using simple accounting methods, soft-linking tools, incorporating cross-systems considerations in sectoral models, or using one modelling tool to represent CLEW systems. This paper describes how a CLEWs quantitative analysis can be performed using one single modelling tool, the Open Source Energy Modelling System (OSeMOSYS). Although OSeMOSYS was primarily developed for energy systems analysis, the tool’s functionality and flexibility allow for its application to CLEWs. A step-by-step explanation of how climate, land, energy, and water systems can be represented with OSeMOSYS, complemented with the interpretation of sets, parameters, and variables in the OSeMOSYS code, is provided. A hypothetical case serves as the basis for developing a modelling exercise that exemplifies the building of a CLEWs model in OSeMOSYS. System-centred scenario analysis is performed with the integrated model example to illustrate its application. The analysis of results shows how integrated insights can be derived from the quantitative exercise in the form of conflicts, trade-offs, opportunities, and synergies. In addition to the modelling exercise, using the OSeMOSYS-CLEWs example in teaching, training and open science is explored to support knowledge transfer and advancement in the field.

PDSI Reconstruction from Tree Rings in Central Siberia (Russia)

This report describes an international summer course, “Tree Rings, Climate, Natural Resources, and Human Interaction”, held in Cheriomushki, Russia, in the summer of 2018. The course was attended by 12 participants from six countries (Belgium, India, Lebanon, Poland, Russia, and South Africa) and instructors from the USA and included basic training in dendrochronology skills and dendroclimatology and dendroecology projects. This report focuses on a nested May–July Palmer Drought Severity Index (PDSI) reconstruction from annual rings of Pinus sylvestris trees growing in the region and also explores false-ring (FR) occurrence in samples collected during the course. Four chronologies, one developed during the course from Maina District, Khakassia, Russia, are used in the reconstruction, which was based on principal component (PC) regression. The nested reconstruction demonstrated a strong statistical relationship between PDSI and tree-ring growth and allowed for an assessment of climate variability on both interannual and interdecadal time scales. FR occurrence in tree cores collected along an elevational transect from a site along the Yenisei River north of Cheriomushki was found to differ depending on the position of trees on the slope. The frequency of FRs and the location of the FR within the annual ring also appear to be related to seasonal precipitation anomalies.

Interspecific competition limits bird species' ranges in tropical mountains.

Species' geographic ranges are limited by climate and species interactions. Climate is the prevailing explanation for why species live only within narrow elevational ranges in megadiverse biodiverse tropical mountains, but competition can also restrict species' elevational ranges. We test contrasting predictions of these hypotheses by conducting a global comparative test of birds' elevational range sizes within 31 montane regions, using more than 4.4 million citizen science records from eBird to define species' elevational ranges in each region. We find strong support that competition, not climate, is the leading driver of narrow elevational ranges. These results highlight the importance of species interactions in shaping species' ranges in tropical mountains, Earth's hottest biodiversity hotspots.

Soil carbon quantity and form are controlled predominantly by mean annual temperature along 4000 km North-South transect of Eastern China

The forest ecosystem plays a key role in mitigating global climate change through carbon sequestration in its biomass and soils to limit the rising atmospheric concentration of CO2. However, the combined overall interaction of climate and forest type on the quantities and forms of soil carbon (organic vs. inorganic) has not yet been sufficiently investigated. In this study, the contents of soil total carbon (STC), soil organic carbon (SOC) and soil inorganic carbon (SIC) were measured along the 4000 km North-South Transect of Eastern China. We sampled 252 soil samples (6 replicates for each site, 3 depths for each site) from four long-term ecosystem experimental stations in Dinghushan, Shennongjia, Beijing and Changbaishan, along the transect from south to north, including 14 different forest types. The contents of STC, SOC, and SIC in the upper 60 cm soil layer varied in different types of forest with 34–107 g C kg−1, 31–104 g C kg−1, and 1.5–8 g C kg−1, respectively. The northern fir and birch forest, most notably in Changbaishan, had the highest STC and SOC contents. The higher SIC contents were found in the southern evergreen broad-leaved forests in Dinghushan and Shennongjia. The contents of STC, SOC and SIC differed significantly in terms of mean annual temperature (MAT), mean annual precipitation (MAP), forest type, and soil depth. In the upper 60 cm soil layer, the most significant correlations occurred between SOC (or STC) and MAT (R2SOC = −0.62, R2STC = −0.60) when compared with the correlation between SOC (or STC) and MAP (R2SOC = −0.45, R2STC = −0.45) or elevation (R2SOC = 0.48, R2STC = 0.48). The soil stratification ratio (SR) of STC and SOC were typically ∼2–3 in most forests and even reached 5– 7 in Changbaishan forest, indicating a well-functioning ecosystem overall. We concluded that on the near-continental scale (4000 km), forest soil carbon contents and forms (SOC, STC, SIC) were controlled most strongly by temperature (MAT). Therefore, an innovative selection of a specific forest type (fir or broad-leaved forest) within set temperature regimes can better contribute to maximizing soil carbon content and thus optimize its sequestration on the national to near-continental scale to mitigate climate change.

Seagrass Factor in Climate Change Mitigation in the Philippines

Despite their importance, seagrasses are facing a global decline due primarily to increased nutrient loading and sedimentation resulting from deforestation and agriculture, and, more recently, from seawater warming in shallow coastal waters. With the advent of new technology and a concerted understanding of seagrass ecosystems as vulnerable social-ecological systems, there has been a dramatic increase in the number of studies focusing on the effects of climate change on seagrasses. Here, I provide an account of the status, role, and future of Philippine seagrasses in an era of climate-driven environmental change. I have gathered information from published studies and actual accounts to identify potential commonalities in the effects of climate change and the responses of seagrasses across the molecular, community, and ecosystem levels. Occupying 13.3% or 4,826 km of the total length of the Philippine coastline, seagrass species composition and diversity remain relatively stable. The seagrass beds of the Philippines and Southeast Asia are declining at an estimated rate of 2.62% or 391 km2 yr–1. Coupled with the apparent neglect in accounts of global carbon, this decline indicates a potential to lose an effective source of blue carbon useful in mitigating the impacts of climate change. In this study, I evaluate the combined effects of climate change with other environmental stressors on the ecosystem services of seagrasses and emphasize the need to apply the lessons learned from three decades of local studies to provide a more inclusive science-based knowledge of seagrass- climate interaction and a deeper understanding of the ecosystem’s resilience. I conclude by presenting the most significant knowledge and management gaps and future directions for seagrass research in the Philippines.

Reclamation of Salt-Affected Land: A Review

Reclamation of salt-affected soil has been identified by the FAO as being critical to meet the needs to increase agricultural productivity. This paper reviews commonly used reclamation methods for salt-affected soils, and provides critical identifiers for an effective reclamation practice of salt-affected soil. There are widely used methods to reduce salinity and sodicity of salt-affected soils, including salt leaching, addition of amendments, revegetation using halophytes and salt scrapping. Not all reclamation techniques are suitable for salt-affected land. The reclamation strategy must be tailored to the site, and based on understanding the soil, plant and climate interactions. On some occasions, a combination of techniques may be required for reclamation. This can include salt scrapping to remove salts from the surface soil, the addition of physical amendments to improve soil pore systems and enhance salt leaching, followed by amelioration of soil by chemical amendments to preserve soil physical conditions, and then halophyte establishment to expand the desalinization zone. This study reveals that soil hydro-geochemical models are effective predictive tools to ascertain the best reclamation practice tailored to salt-affected land. However, models need to be calibrated and validated to the conditions of the land before being applied as a tool to combat soil salinity.

Modeled interactions of mountain pine beetle and wildland fire under future climate and management scenarios for three western US landscapes

BackgroundMountain pine beetle (MPB) is a native disturbance agent across most pine forests in the western US. Climate changes will directly and indirectly impact frequencies and severities of MPB outbreaks, which can then alter fuel characteristics and wildland fire dynamics via changes in stand structure and composition. To investigate the importance of MPB to past and future landscape dynamics, we used the mechanistic, spatially explicit ecosystem process model FireBGCv2 to quantify interactions among climate, MPB, wildfire, fire suppression, and fuel management under historical and projected future climates for three western US landscapes. We compared simulated FireBGCv2 output from three MPB modules (none, simple empirical, and complex mechanistic) using three focus variables and six exploratory variables to evaluate the importance of MPB to landscape dynamics.ResultsWe found that inclusion of MPB (empirical or mechanistic) in the simulations significantly changed past and future landscape dynamics and that the mechanistic MPB module had more cross-scale interactions that increased variability, and perhaps realism, of simulation results. We also evaluated impacts of fire and fuel management on MPB dynamics and found that fire suppression influenced fuel loadings more than MPB disturbance, but at a landscape scale, most fuel treatment programs did little to change fuel loadings, MPB dynamics, and burned area, except under high fire suppression.ConclusionsSynergistic interactions of climate, MPB, and wildfire catalyzed landscape-scale changes in vegetation distributions, fuels, and fire regimes in FireBGCv2 simulations. Models that simulate climate change on pine-dominated landscapes may be improved by including mechanistic MPB simulations to account for potentially important ecological interactions.

The ecohydrological effects of climate and landscape interactions within the Budyko framework under non-steady state conditions

Catchment water yield is controlled by the partitioning of precipitation into evapotranspiration, runoff, and water storage changes. As one form of the Budyko framework, Fu's equation has been widely employed to estimate the influences of climatic factors and landscape characteristics on the precipitation partitioning, with a single parameter ω reflecting the integrated ecohydrological effects of these influencing factors. However, the ecohydrological effects under non-steady state conditions are not fully understood owing to the complex hydrological and ecological processes at finer spatial and temporal scales. In addition, the finer spatial and temporal scales limit the application of the Budyko framework, since the original framework assumes that water storage changes are negligible. In this study, combining two hydrological models (the abcd model and GR2M model) and Fu's equation based on an extended Budyko framework, we estimated the ecohydrological effects of climatic factors and landscape characteristics under non-steady state conditions for 59 small catchments (≤9805 km2) in Qinba Mountains. The outputs of the two hydrological models exist good consistency with satellite-based data, with NSE exceeding 0.5 in 93% and 97% of catchments, respectively. Factors influencing the precipitation partitioning vary with timescale and exhibit greater variability at intra-annual scales. Moreover, the hydrological effects of these time-varying factors are influenced by catchment characteristics (R2 ranging from 0.01 to 0.68), implying the precipitation partitioning is controlled by the ecohydrological interactions of climate and landscape at different timescales.

Microstratigraphy and palaeoenvironmental implications of a Late Quaternary high‐altitude lacustrine record in the subtropical Andes

AbstractHigh‐mountain lake records in semiarid foreland settings, such as the central Andes of North‐western Argentina, are highly restricted and often deprived of well‐preserved microstratigraphic information to analyze palaeoenvironmental changes and their causes, particularly for periods prior to the Last Glacial Maximum. Laguna La Salada Grande (23°S/65°W, 4063 metres above sea‐level) is a closed shallow lake located at Cordillera Oriental, North‐western Argentina with a unique depositional record, including geomorphic and stratigraphic evidence of palaeoenvironmental changes since the Late Pleistocene. In order to understand the depositional dynamics of this mountain lacustrine system at different timescales, limnogeological multiproxy analyses together with a radiocarbon and 210Pb‐based chronology were applied on massive and laminated sediments from La Salada Grande. Laminated deposits were further analyzed using novel sub‐centimetric mineralogical, textural and geochemical automated methods (including a combination of micro‐X‐ray fluorescence and quantitative evaluation of minerals by scanning electron microscopy (QEMSCAN®). Thick laminated microfacies at the beginning of the sequence record a deep and organic matter productive palaeolake prior to ca 34 ka (1 ka = 1000 years before 1950), that changed into a highly fluctuating shallower‐palaeolake with frequent detrital influxes after ca 34 ka. Microstratigraphy of the coarser‐grained detrital laminae between 31 ka and 25 ka reveals irregular and probably sub‐centennial high‐energy discharge events, pointing to convective atmospheric activity as the main trigger. After ca 21 ka the lake evolved to deeper water‐level conditions resulting in fine‐grained deposits with limited delivery of coarse‐grained sediments, followed by an abrupt lake level drop and incision. The multi‐millennial palaeoenvironmental reconstruction of La Salada Grande, and its correlation with other palaeoclimate records, shows a close link between the lacustrine depositional processes and palaeoclimate changes associated with the South American summer monsoon dynamics. This multifocal research in such an understudied environment provides key knowledge about lacustrine functioning and discharge events−climate interactions of mountain lakes of semi‐arid climates.

Late Cenozoic locally landslide-dammed lakes across the Middle Yangtze River

Understanding the drainage history of the Middle Yangtze River is critical for determining its interaction of tectonics, climate, and denudation. Previous studies have focused on interpreting the provenance of the Xigeda lacustrine sediments, however, the poorly constrained ages of these sediments mean that the evolutionary history remains elusive. Here, we present new cosmogenic 10Be, 21Ne and 26Al data from the Dadu and Anning river sediments, indicating deposition ages of paleo-lake sediments between ~1 and ~0.5 Ma. Paleo-denudation rates together with neon isotopic composition and topographic analysis suggest that there was no connection between the Dadu and Anning rivers during the Middle Pleistocene. Combined with field investigations and cosmogenic nuclides ages, we suggest that paleo-lakes formed upstream of channel blocking landslides, which in turn could have been the result of external forcings, such as earthquakes, debris flows, increased precipitation, and glaciation. Previous thermochronology data constrain the fluvial incision of the paleo-Dadu-Anning River to have enhanced between ~13–9 Ma. Subsequently, our cosmogenic results show paleo-lakes were formed (~1 Ma) after the paleo-Dadu-Anning River capture (~2 Ma). Finally, the draining of paleo-lakes occurred at ~0.5 Ma.

Tree-Ring Isotopic Records Suggest Seasonal Importance of Moisture Dynamics Over Glacial Valleys of the Central Himalaya

Accelerated glacier mass loss is primarily attributed to greenhouse-induced global warming. Land–climate interactions have increasingly been recognized as an important forcing at the regional-local scale, but the related effects on the Himalayan glaciers are less explored and thought to be an important factor regulating spatial heterogeneity. The aim of the present study is a multi-decadal approximation of glacier—hydroclimate interaction over the western region of the central Himalaya (WCH). Multi-species, highly coherent, tree-ring cellulose δ18O chronologies from three sites across the WCH were used to derive atmospheric humidity (Atmospheric Moisture Content: AMC) record of the last four centuries. Annual-scale AMC reconstruction implies a decreasing regional atmospheric moisture since the mid-19th century and a sharp decline in recent decades (1960s). Coherency analyses between regional AMC and glacier mass balance (GMB) indicate an abrupt phase-shift in the relationship after the 1960s within a common record of the last 273 years. To ascertain the cause of this phase-shift, annual AMC was disintegrated into seasonal-scale, utilizing ∼200 years of δ18O record of a deciduous tree species. Seasonal (winter: October–March; summer: April–September) AMC reconstructions and disaggregation results indicate higher sensitivity of regional ice-mass variability to winter moisture dynamics than summer.Winter season AMC reconstruction confirms a revival of winter westerlies-driven moisture influx in the region since the 1970 s. Meanwhile, the record for the summer season AMC indicates a gradual decline in moisture influx from the beginning of the 20th century. Interestingly, despite a prominent decline in Indian summer monsoon (ISM) precipitation after the mid-20th century, the summer season AMC—GMB relation remained stable. We hypothesize that decadal-scale greening, and consequently increased evapotranspiration and pre-monsoon precipitation might have been recycled through the summer season, to compensate for the ISM part of precipitation. However, isotope-enabled ecophysiological models and measurements would strengthen this hypothesis. In addition, high-resolution radiative forcing and long-term vegetation greening trends point towards a probable influence of valley greening on GMB. Our results indicate that attribution of ice mass to large-scale dynamics is likely to be modulated by local vegetation changes. This study contributes to the understanding of long-term hydroclimate—ice mass variability in the central Himalaya, where predictions are crucial for managing water resources and ecosystems.

Evaluating dual exposure by using climate-conflict vulnerability index on the coastal districts of Sindh, Pakistan.

Climate variability is widely recognized as a major concern, particularly in resource-scarce regions where it limits livelihood opportunities by putting additional strain on already depleting resources, resulting in human insecurity and conflicts. Some vulnerability assessments have created a nexus between climate variability and conflicts. The Climate-Water Conflict Vulnerability Index (CWCVI) and the Climate-Agriculture Conflict Vulnerability Index (CACVI) are applied as a tool for exploring the climate and conflict interactions, as well as contrasting the vulnerabilities of the coastal districts of Badin, Thatta, and Sujawal. The analysis incorporates a dual exposure of communities in the form of climate variability and conflict over water and agricultural resources. The study finds that aggression and feelings of insecurity about depleting resources are the main contributing indicators of climate-conflict vulnerability in the coastal districts. District Sujawal showed higher vulnerability in adaptive capacity as compared to the other districts due to poor infrastructure and high dependency on natural resources. However, the district of Badin demonstrated high vulnerability in terms of sensitivity and its exposure to conflicts over agricultural resources is high. The overall CWCVI and CACVI scores were higher in Badin and Thatta, respectively. This study identifies a number of indicators that can be used to improve the efficacy of mitigation strategies to reduce conflict vulnerability in future policy directions and resource planning.

Complex Interplay Between Organic and Secondary Inorganic Aerosols With Ambient Relative Humidity Implicates the Aerosol Liquid Water Content Over India During Wintertime

AbstractAerosol Liquid Water Content (ALWC), a ubiquitous component of atmospheric aerosols, modulates atmospheric chemistry through aerosol surface reactions and reduces the atmospheric visibility. However, the complex dependency of ALWC on aerosol chemistry and relative humidity (RH) in the Indian region remains poorly characterized. Here, we combine available measurements of aerosol chemical composition with thermodynamic model, ISORROPIA2.1, to reveal a comprehensive picture of ALWC in fine mode aerosols during the winter season over the Indian continental region. The factors modulating ALWC are primarily dependent on the RH, such that the effect of aerosol dry mass and hygroscopicity are significant at high RH while the effect of hygroscopicity significantly reduces with decreasing RH. ALWC is observed to display a sharp non‐linear rise, beyond a critical value of ambient RH dependent on the particle hygroscopicity. Further analysis by coupling Weather Research Forecasting‐Chem simulation with ISORROPIA2.1 revealed significant spatial heterogeneity in ALWC over India, strongly associating with regions of high aerosol mass loading and RH. The Indo‐Gangetic Plain is consequently observed to be a hotspot of higher ALWC, which explains the prevalent conditions of haze and smog during winter in this region. Our findings re‐emphasize that high aerosol mass resulting from intense pollution is vital in modulating aerosol–climate interaction under favorable meteorological conditions. Observations suggest the need for localized pollution control strategies, directed at the reduction in aerosol emissions of specific chemical composition observed to contribute to the enhancement in PM through an increase in ALWC during wintertime in the region.

Direct genetic effects, maternal genetic effects, and maternal genetic sensitivity on prenatal heat stress for calf diseases and corresponding genomic loci in German Holsteins

The aim of this study was to infer the effects of heat stress (HS) of dams during late gestation on direct and maternal genetic parameters for pneumonia (PNEU, 112,563 observations), diarrhea (DIAR, 176,904 observations), and omphalitis (OMPH, 176,872 observations) in Holstein calves kept in large-scale co-operator herds. The genotype dataset included 41,135 SNPs from 19,247 male and female cattle. Temperature-humidity indices (THI) during the last 8 wk of pregnancy were calculated, using the climate data from the nearest public weather station for each herd. Heat load effects were considered for average weekly THI larger than 60. Phenotypically, regression coefficients of calf diseases on prenatal THI during the last 8 wk of gestation were estimated in 8 consecutive runs. The strongest detrimental effects of prenatal HS on PNEU and DIAR were identified for the last week of pregnancy (wk 1). Thus, only wk 1 was considered in ongoing genetic and genomic analyses. In an advanced model considering prenatal HS, random regression coefficients on THI in wk 1 nested within maternal genetic effects (maternal slope effects for heat load) were considered as parameters to infer maternal sensitivity in response to prenatal THI alterations. Direct heritabilities from the advanced model ranged from 0.10 (THI 60) to 0.08 (THI 74) for PNEU and were close to 0.16 for DIAR. Maternal heritabilities for PNEU increased from 0.03 to 0.10 along the THI gradient. For DIAR, the maternal heritability was largest (0.07) at the minimum THI (THI = 60) and decreased to 0.05 at THI 74. Genetic correlations smaller than 0.80 for PNEU and DIAR recorded at THI 60 with corresponding diseases at THI 74 indicated genotype by climate interactions for maternal genetic effects. Genome-wide associations studies were performed using de-regressed proofs of genotyped sires for direct genetic, maternal genetic, and maternal slope effects. Thirty suggestive and 2 significant SNPs were identified from the GWAS. Forty-three genes located close to the suggestive SNPs (±100 kb) were annotated as potential candidate genes. Three biological processes were inferred on the basis of the these genes, addressing the negative regulation of the viral life cycle, innate immune response, and protein ubiquitination. Hence, the genetics of prenatal heat stress mechanisms are associated with immune physiology and disease resistance mechanisms.