Substantial Precipitation Research Articles

Interannual variations of terrestrial water storage in the East African Rift region

Abstract. The US–German GRACE (Gravity Recovery and Climate Experiment, 2002–2017) and GRACE-FO (GRACE Follow-On, since 2018) satellite missions observe terrestrial water storage (TWS) variations. Over 20 years of data allow for investigating interannual variations beyond linear trends and seasonal signals. However, the origin of observed TWS changes cannot be determined solely with GRACE and GRACE-FO observations. This study focuses on the northern part of the East African Rift around the lakes of Turkana, Victoria, and Tanganyika. It aims to characterise and analyse the interannual TWS variations compared to meteorological and geodetic observations of the water storage compartments (surface water, soil moisture, and groundwater). We apply the STL (Seasonal-Trend decomposition using LOESS) method to decompose the signal into a seasonal signal, an interannual signal, and residuals. By clustering the interannual TWS dynamics for the African continent, we define the exact outline of the study region. We observe a TWS decrease until 2006, followed by a steady rise until 2016, and then the most significant TWS gain in Africa in 2019 and 2020. Besides meteorological variability, surface water storage variations in the lakes explain large parts of the TWS decrease before 2006. The storage dynamics of Lake Victoria alone contribute up to 50 % of these TWS changes. On the other hand, the significant TWS increase around 2020 can be attributed to nearly equal rises in groundwater and surface water storage, which coincide with a substantial precipitation surplus. Soil moisture explains most of the seasonal variability but does not influence the interannual variations. As Lake Victoria dominates the surface water storage variations in the region, we further investigate the lake and the downstream Nile River. The Nalubaale Dam regulates Lake Victoria's outflow. Water level observations from satellite altimetry reveal the impact of dam operations on downstream discharge and on TWS decreases in the drought years before 2006. On the other hand, we do not find evidence for an impact of the Nalubaale Dam regulations on the strong TWS increase after 2019.

Integrating remote sensing modeling for drought assessment and vegetation monitoring in El Tarf, Algeria: a 40-year analysis

The escalating frequency and intensity of drought events, exacerbated by anthropogenic climate change, present critical challenges to hydrological resources, ecosystem resilience, and agricultural productivity. In North Africa, and specifically Algeria, comprehending the spatiotemporal patterns of drought is essential for sustainable water resource management and ecological conservation. This investigation focuses on the El Tarf region, located in northeastern Algeria, recognized for its ecological diversity and agricultural relevance. Employing a synergistic methodology, this study integrates the Standardized Precipitation Evapotranspiration Index (SPEI) for long-term drought severity evaluation with the Normalized Difference Vegetation Index (NDVI) to monitor vegetation phenology and health over time. Utilizing the computational power of Google Earth Engine, we process extensive temporal datasets of SPEI spanning from 1980 to 2023, complemented by high-resolution satellite imagery for NDVI computation. This comprehensive approach facilitates an in-depth analysis of drought dynamics, their severity, and impacts on vegetative cover in El Tarf over the past four decades. Our findings indicate significant long-term drought trends, with notable dry spells occurring between 1994 and 2003. Severe drought events were particularly pronounced in December 2022 (SPI = -2.50) and May 2002 (SPI = -2.2), correlating with substantial precipitation deficits. Although areas experiencing extreme drought have diminished, there has been an increase in moderate drought occurrences, suggesting an uptick in drought frequency, which poses risks to hydrological resources and ecosystem health. These observed patterns align with regional climate change projections, highlighting an urgent necessity for adaptive management strategies in agriculture and water resources.

Integration of interpretable machine learning and environmental magnetism elucidates reduction mechanism of bioavailable potentially toxic elements in lakes after monsoon

Little information is available on the influence of substantial precipitation and particulate matter entering during the monsoon process on the release of potentially toxic elements (PTEs) into lake sediments. Sediments from a typical subtropical lake across three periods, pre-monsoon, monsoon, and post-monsoon, were collected to determine the chemical forms of 12 PTEs (As, Cd, Co, Cr, Cu, Fe, Hg, Pb, Mn, Ni, Sb, and Zn), magnetic properties, and physicochemical indicators. Feature importance, Shapley additive explanations, and partial dependence plots were used to explore the factors influencing bioavailable PTEs. The proportion of bioavailable forms of PTEs decreased from 3.85 % (Cd) to 87.84 % (Hg) after the monsoon. Gradient extreme boosting demonstrated robust fitting accuracy for the prediction of the bioavailable forms of the 12 PTEs (R2 > 0.84). Shapley additive explanations identified that the bioavailable forms were influenced by the total PTE concentrations, wind, shortwave radiation, and particle inputs (25.1 %–88.5 % for total importance), either individually or in combination. The partial dependence plots highlighted the influence thresholds of background values and anthropogenic factors on the bioavailable forms of PTEs. Changes in environmental properties could indicate the process of external sediment influx into lakes. The optimized model combined with magnetic parameters showed strong performance in other cases (coefficient of determination>0.58), confirming the ubiquitous decrease in bioavailable forms of PTEs in sediments across subtropical lakes after monsoons.

The interplay between medicanes and the Mediterranean Sea in the presence of sea surface temperature anomalies

This study examined three Mediterranean Sea cyclones classified as medicanes: Zorbas, Ianos, and Apollo. All three cyclones traversed warm-core eddies during their propagation. We investigated the role of those eddies in the cyclones' development and the responses of those eddies to the passage of a cyclone. Cyclones Zorbas and Apollo intensified considerably in close proximity to warm-core eddies; whereas Ianos, the strongest cyclone ever recorded in the Mediterranean Sea (reaching Category 2), underwent marginal intensification. In the case of Ianos, a strong marine heatwave was present during the intensification, releasing more latent and sensible heat fluxes due to the high ocean heat content, which masked the effect of the warm core eddy. For Zorbas and Apollo, the intensification above the warm-core eddy was accompanied by moisture convergence at the warm-core eddy, yielding substantial precipitation. In the case of Ianos, the convergence of moisture and subsequent precipitation aligned with the occurrence of a marine heatwave. For Zorbas and Apollo, chlorophyll-a concentrations and Phytoplankton increased after the cyclone passed over a warm-core eddy; whereas for Ianos, they increased near the site of a marine heatwave. All three cyclones responded similarly to elevated temperatures at the mesoscale (i.e., warm-core eddy) and regional scale (i.e., marine heatwave).

Revisiting the evolution of downhill thunderstorms over Beijing: a new perspective from a radar wind profiler mesonet

Abstract. Downhill thunderstorms frequently occur in Beijing during the rainy seasons, leading to substantial precipitation. The accurate intensity prediction of these events remains a challenge, partly attributed to insufficient observational studies that unveil the thermodynamic and dynamic structures along the vertical direction. This study provides a comprehensive methodology for identifying both enhanced and dissipated downhill thunderstorms. In addition, a radar wind profiler (RWP) mesonet has been built in Beijing to characterize the pre-storm environment downstream of the thunderstorms at the foothill. This involves deriving vertical distributions of high-resolution horizontal divergence and vertical motion from the horizontal wind profiles measured by the RWP mesonet. A case study of an enhanced downhill thunderstorm on 28 September 2018 is carried out for comparison with a dissipated downhill thunderstorm on 23 June 2018, supporting the notion that a deep convergence layer detected by the RWP mesonet, combined with the enhanced southerly flow, favors the intensification of thunderstorms. Statistical analyses based on radar reflectivity from April to September 2018–2021 have shown that a total of 63 thunderstorm events tend to be enhanced when entering the plain, accounting for about 66 % of the total number of downhill thunderstorm events. A critical region for intensified thunderstorms lies on the downslope side of the mountains west to Beijing. The evolution of a downhill storm is associated with the dynamic conditions over the plain compared to its initial morphology. Strong westerly winds and divergence in the middle of troposphere exert a critical influence on the enhancement of convection, while low-level divergence may lead to dissipation. The findings underscore the significant role of an RWP mesonet in elucidating the evolution of a downhill storm.

Quantifying the influence of atmospheric rivers on rainfall over the Jianghuai River Basin during the 2022 Mei‐yu season

AbstractAtmospheric rivers (ARs) are narrow, elongated belts of intense water vapor transport that often occur in mid‐latitude areas and are the primary drivers of heavy precipitation in these regions. This study investigates the impact of ARs on precipitation patterns in the Jianghuai River Basin during the Mei‐yu period. Focusing on a specific rainstorm event on June 27, 2022, we analyze atmospheric circulation, water vapor attributes, and transport trajectories. Three distinct classes of grids (Class A, significantly influenced by ARs; Class B, moderately affected; and Class C, untouched by ARs) are identified based on their response to ARs. Class A grids, located centrally, experience substantial precipitation, with a higher probability of rainstorm events. Class B grids, situated at a distance from ARs, exhibit moderate precipitation and a longer duration of rainy days. Class C grids, minimally affected by ARs, experience minimal precipitation with almost no chance of rainstorm events. The results from grid‐based analysis emphasize the localized influence of ARs, indicating a 8–30 times increase in precipitation intensity of Class A compared to Class C. The 23‐day Mei‐yu period is further categorized into AR days and non‐AR days, revealing that ARs amplify precipitation intensity by 2–5 times on average. Grid‐based and day‐based analyses provide complementary insights, with the former offering a broader spatial perspective and the latter emphasizing temporal distinctions. These findings underscore the nuanced influence of ARs on precipitation, emphasizing their role in extreme events and highlighting the importance of considering both spatial and temporal factors in understanding precipitation variability.

Influences of quenching rate on mechanical and corrosion properties of Al-Cu-Li alloy

The study investigated the influence of the quenching rate on the mechanical and corrosion properties of Al-Cu-Li alloys through immersion end-quenching experiments, tensile properties tests, intergranular corrosion (IGC) tests, and microstructure characterization. The research results show that a decrease in the quenching rate leads to substantial precipitation and growth of the quenching-induced θ and T1 phases. This process consumes Cu atoms within the matrix, leading to a reduction in the precipitation of the T1 strengthening phase during the aging process, which in turn decreases the strength. Meanwhile, there is a rise in the amount of quenching-induced T1 phases at (sub)grain boundaries ((S)GBs) and the width of the precipitate-free zone (PFZ) at GBs. This leads to preferential corrosion along the (S)GBs, which causes corrosion to propagate deeper along the (S)GBs. Additionally, a large number of the quenching-induced T1 phases are present within the grain, resulting in corrosion extension within the grain and subsequently decreasing the corrosion properties of the alloy.

Microstructure and mechanical properties in ultrasonic-magnetic field coaxial hybrid GTAW joints of Ti-6Al-4V

GTAW has less arc energy density and coarse joint microstructure. A novel method of Ultrasonic-Magnetic field coaxial hybrid GTAW (U-M-GTAW) was proposed, which improved upon the traditional GTAW torch. Under 140 A current and 4 mm/s speed, the results indicated that the U-M-GTAW depth-to-width ratio increased by 54.5 % compared to GTAW. Meanwhile, the surface of the joint showed a dense corrugation. The interior of the joints was all composed of martensite α', whose phase transformation obeyed the Burgers orientation relationship. The average martensite length in the U-M-GTAW weld zone was 14.8 μm, which was 33.6 % shorter than GTAW, and the length distribution was more uniform. Additionally, the U-M-GTAW joint orientation shifted from {01−10} to {−12−10}, revealing a higher texture density. The substantial precipitation of martensite in the weld zone resulted in the highest hardness, with an average microhardness of 396.8 ± 9.0 HV, marking a 12.1 % improvement over base metal. Moreover, U-M-GTAW exhibited an elongation of 9.3 %, representing a 10.7 % enhancement compared to GTAW, with deeper dimples in the fracture indicating superior plasticity. Notably, the improvements in microhardness and elongation in U-M-GTAW were primarily attributed to the reduction in martensite length and its uniform distribution under the action of ultrasonic and magnetic fields.

Response of evapotranspiration to the 2022 unprecedented extreme drought in the Yangtze River Basin

AbstractThe response of evapotranspiration (ET) to drought is essential for understanding water availability under drought conditions, which has received increasing scientific attention but remains highly uncertain. An unprecedented extreme drought sweeping the whole Yangtze River Basin during the summer and autumn of 2022 provides a novel opportunity to explore the ET response to drought within large river basins. Here, we apply multiple ET products to investigate the spatiotemporal variation of ET during the 2022 extreme drought and analyse the response of ET to drought in the Yangtze River Basin. The results show that this drought, characterized by widespread substantial precipitation deficit and high level of atmospheric evaporative demand (AED), leads to evident abnormal ET. Over the whole basin, ET exhibits a notable increase in the initial 2 months of this drought, which can significantly reduce water availability. However, despite continued high AED, the increase in ET fails to remain in the following months due to limited moisture supply. This suggests that ET response to drought varies as drought progresses. Among other drought events from 2003 to 2022, the response of ET is similar to that in the 2022 extreme drought. Specifically, for most sub‐basins, ET typically shows positive anomalies in the early stage of drought, followed by negative anomalies in the late stage. Generally, our findings improve the understanding of the dynamic response of ET to drought at the basin scale, which is crucial for basin water security.

Modulation of evapotranspiration and stream runoff by weathered bedrock in arid and semi-arid mountains

Earth's Critical Zone exhibits remarkable heterogeneity and complexity. Hence, further investigation is required to examine the composition of Earth's Critical Zone as well as the diverse eco-hydrological patterns they exhibit under varying climatic and geological circumstances. This exploration should primarily be conducted through the investigation and experiments of the hillslope unit, where the topography and weathered bedrock are representative, with particular emphasis on semi-arid regions where water resources serve as the primary limiting factor. Here, we have determined that the structure of the weathering profile displays systematic variation across the topography and heterogeneous landscape on uninterrupted slopes. Differences in the structure of the subsurface critical zone led to differences in its water storage capacity at the same time. Runoff in alpine shrubs and forests was dominated by subsurface runoff, and grassland was dominated by surface runoff. In the alpine shrub immediately adjacent to the watershed, an estimated quantity of 129 mm of water is stored within the unsaturated zone of the soil, serving as exchange water to replenish moisture in the underlying bedrock. In contrast to alpine shrubs, an estimated quantity of 62.7 mm of water originates from the unsaturated zone of soil and weathered bedrock in the forest. However, approximately 21.1 mm of moisture is unavailable to plants. The soil water storage in grasslands exhibits a decline throughout the growing season, with a subsequent augmentation occurring solely after substantial precipitation events exceeding 20 mm. In wet years, dynamic storage predominantly manifests as groundwater saturation throughout the entire ground and high subsurface runoff. In dry years, the limited runoff response indicates that the catchment's dynamic water storage primarily comprises “indirect” water storage, which predominantly resides within the soil, saprolite, and weathered rock below the “field capacity”, subsequently being released into the atmosphere through evapotranspiration.

A correlative approach to evaluating the links between local microstructural parameters and creep initiated cavities

The study and modelling of material degradation processes, such as the initiation and growth of creep cavities in high-temperature applications, require a correlative and comprehensive knowledge of the microstructure. However, individual microscopy is limited to a small region and specific microstructural information of the specimen. This work demonstrates a novel correlative microscopy approach for characterising creep cavitation and establishing correlations with local microstructural parameters in a statistical manner. This approach combines datasets from stitched higher-resolution backscattered electron (BSE) images, XeF2 Focused Ion Beam (FIB) images, and backscattered electron diffraction (EBSD) maps with advanced image correlation techniques. Deep-learning image segmentation techniques and statistical analysis are applied to find relations between creep cavitation and local microstructural environment. This approach is demonstrated in a cyclic creep-tested 316H stainless steel specimen with extensive creep cavities. The results show that in this material, strain localization, grain boundary misorientation, and substantial precipitation dominate the nucleation of cavities, whereas other microstructural properties such as grain size and Schmid factor play smaller roles. This study presents the use of the correlative microscopy approach to provide new insights into creep cavitation behaviour and its implications for establishing creep cavitation damage models.

Impact of Deforestation in the Maritime Continent on the Madden–Julian Oscillation

Abstract Deforestation is a major issue affecting both regional and global hydroclimates. This study investigated the effect of deforestation in the Maritime Continent (MC) on tropical intraseasonal climate variability. Using a global climate model with credible Madden–Julian oscillation (MJO) simulations, we examined the effect of deforestation over the MC region by replacing the forest canopy with grassland. The results revealed that under constant orographic and land–sea contrast forcing, the modification of the canopy over the MC altered the characteristics of the MJO. We noted the amplification of the MJO and increases in wet–dry fluctuation and the zonal extent. We analyzed more than 100 MJO cases by performing K-means clustering and determined that the continuous propagation of the MJO over the MC increased from 35% in the control experiment to 61% in the deforestation experiment. This phenomenon of less blocked MJO over the MC in the deforestation run was associated with more substantial precipitation, increased soil moisture, and a suppressed diurnal cycle in land convection. Furthermore, when the MJO convection was over the Indian Ocean (IO), we observed the enhancement of low-level moisture over the MC region in the deforestation experiment. Grassland surface forcing provides a thermodynamic source for triggering instability in the atmosphere, resulting in low-level moisture convergence. The MJO exhibited a stronger energy recharge–discharge cycle in the deforestation experiment than in the control experiment, and this difference between the experiments enlarged as the MJO progressed from the IO to MC.

The Impact of Large-Scale Environments and a Southwest Vortex on Heavy Rainfall in Southern Taiwan in Late May 2020

Abstract This paper investigates the impact of the environmental conditions during the first half of the 2020 mei-yu season (Y20) and the southwest vortex (SWV), as well as their interaction, on heavy precipitation in southern Taiwan during late May 2020, based on a quantitative approach through ensemble simulations. The control experiment successfully replicates observed heavy precipitation in southern and central Taiwan and reveals a positive spatial correlation between precipitation occurrence probabilities and mean accumulated precipitation, emphasizing continuous rainfall accumulation over intermittent extreme events. Comparative analyses with sensitivity experiments elucidate that the Y20, featuring an extended western North Pacific subtropical high, intensify pressure gradients and southwesterly flow near Taiwan, favoring precipitation in windward regions but hindering it in the east. The SWV creates a moist and vortical environment near Taiwan, amplifying moisture supply and westerly winds, promoting precipitation in southern Taiwan, and enhancing frontal activity. The interaction between the SWV and the Y20, though limited in its impact on providing favorable wind and moisture conditions for precipitation southwest of Taiwan, significantly contributes to precipitation in southern Taiwan. The reason is that although the SWV primarily enhances moisture and the Y20 predominantly boost southwesterly flow, creating favorable conditions for rainfall, substantial precipitation occurs only when both factors converge in a nonlinear interaction. The interaction increases frontal activity over the Taiwan Strait and influences the movement and strength of the SWV, enhancing southwesterly flow and moisture flux in southwestern Taiwan.

Enhanced strength-conductivity trade-off in Al-Mg-Si alloys with optimized Mg/Si ratio

This study evaluated the potential for an enhanced strength–conductivity trade-off in Al-Mg-Si alloys with optimized Mg/Si ratios. In cases of the consistent total amounts of Mg and Si atoms, evident differences in hardness and conductivity manifested during artificial aging, contingent on the Mg/Si ratio investigated. The alloy with an Mg/Si ratio of 1.18 displayed a superior trade-off between strength and conductivity, yielding a yield strength of 305 MPa coupled with a remarkable conductivity of 51.57%IACS and 199.7 W/m/K. Alloys characterized by low Mg/Si ratios exhibited a significantly higher precipitates fraction than those with high Mg/Si ratios because of the accelerated age-precipitation kinetics. This resulted in the improved strength owing to the enhanced precipitation strengthening contribution. A constitutive model considering both fraction and structural composition of the precipitates was established to elucidate the mechanism of varying Mg/Si ratio on conductivity. Variations in the residual Mg and Si within the matrix have been demonstrated to predominantly account for the disparities in conductivity across alloys with distinct Mg/Si ratios. The substantial precipitation in the alloy with an Mg/Si ratio of 1.18 induced heightened depletion of both Mg and Si, consequently achieving a comparatively elevated conductivity concomitant with its relatively superior strength.

Drought Variations in the Yili Basin, Northwest China since AD 1673 Based on Tree-Ring Width

The Yili Basin represents a typical region influenced by the Westerlies, and as a result of the substantial precipitation delivered by these winds, it has emerged as a significant hub for agricultural and animal husbandry activities in Central Asia. This study established a 419-year tree-ring width chronology, utilizing living Picea schrenkiana samples from two sampling sites in the Yili Basin. Correlation analysis showed that the standard tree-ring width chronology had the best correlation with the Palmer Drought Severity Index from the previous August to the current May (PDSIP8C5) (r = 0.614, n = 59, p < 0.001). Therefore, we reconstructed PDSIP8C5 variations from 1673 to 2018. The reconstruction results reveal eight wet and seven dry periods during the past 346 years. In the reconstructed series, droughts are particularly pronounced around 1770 and 1920, and the PDSI shows a significant long-term wetting trend since the 1980s. The solar activity, North Atlantic Oscillation (NAO), and Atlantic Multidecadal Oscillation (AMO) jointly influenced the regional moisture variation.

Influence of BaO and MgO on viscosity, crystalline phase, and structure of CaO–Al2O3–10%SiO2–20%CaF2-based system

In the current study, the low SiO2 mold flux for the continuous casting of the transformation-induced plasticity steel was studied to avoid the interface reaction between the dissolved aluminum in the molten steel and silica in the mold flux. The viscometer, Raman spectra, and X-ray disproportion were employed to study the viscosity, melt structure, and crystalline phase of the mold flux, respectively. The viscosity of the mold flux decreased with the replacement of MgO by BaO due to the balance of the melt structure and the precipitation phase. The aluminosilicate and silicate structures were depolymerized to simpler units with the replacement of MgO by BaO in the mold flux since a preference that Ba2+ tended to act as a charge compensator. The viscosity of the mold flux roughly increased with the addition of the total BaO and MgO content due to the formation of the MgAl2O4 phase in the pure liquid phase. The substantial precipitation of the MgAl2O4 phase in the liquid melt caused a sharp increase in the viscosity of the mold flux, which should be avoided by lowering the MgO content to less than 3 wt%.

GIS-based hydrodynamic modeling for urban flood mitigation in fast-growing regions: a case study of Erbil, Kurdistan Region of Iraq

Floods threaten urban infrastructure, especially in residential neighborhoods and fast-growing regions. Flood hydrodynamic modeling helps identify flood-prone locations and improve mitigation plans' resilience. Urban floods pose special issues due to changing land cover and a lack of raw data. Using a GIS-based modeling interface, input files for the hydrodynamic model were developed. The physical basin's properties were identified using soil map data, Land Use Land Cover (LULC) maps, and a Digital Elevation Model (DEM). So, the HEC-RAS 2-D hydrodynamic model was developed to estimate flood susceptibility and vulnerability in Erbil, Iraq. The case study examines the quality of flood modeling results using different DEM precisions. Faced with the difficulty, this study examines two building representation techniques: Building Block (BB) and Building Resistance (BR). The work presented here reveals that it is possible to apply the BR technique within the HEC-RAS 2-D to create urban flood models for regions that have a lack of data or poor data quality. Indeed, the findings confirmed that the inundated areas or areas where water accumulated in past rainfall events in Erbil are the same as those identified in the numerical simulations. The study's results indicate that the Erbil city is susceptible to flood hazards, especially in areas with low-lying topography and substantial precipitation. The study's conclusions can be utilized to plan and develop flood control structures, since it identified flood-prone areas of the city.

Evaluating Contemporary and Future-Scenario Substantial-Precipitation Events in the Missouri River Basin Using Object-Oriented Analysis

The Missouri River Basin is the largest single river basin in the United States, and, as such, it plays an important role in natural ecosystems as well as the country’s economy, through agriculture, hydroelectric power generation, and transportation. Episodes of heavy precipitation can have a substantial negative impact on all these aspects of the basin, so understanding how well these episodes are simulated and projected to change in the future climate is important. We analyzed contemporary and projected mid-century behavior of heavy-precipitation episodes using an object-oriented analysis to diagnose short-term (≥5-day) and extended-period (≥30-day) events with substantial precipitation, using PRISM gridded, observed precipitation and RegCM4 regional-climate simulations that used outputs from two different GCMs for boundary conditions. The simulations were produced for the North American portion of the CORDEX program. A 25 km grid was used for the simulations and for aggregated PRISM precipitation. Overall, the simulated contemporary-climate events compared favorably with the PRISM events’ frequency and duration. The simulated event areas tended to be larger than the areas in the PRISM events, suggesting that the effective resolution of the simulations is greater than 25 km. Event areas and durations change little going from contemporary to scenario climate. The short-term events increase in frequency by an amount commensurate with the increase in mean precipitation simulated for the basis. However, the extended-term events showed little change in frequency, despite the average precipitation increase. Roughly half the extended-period events overlapped with at least one short-term event in both the observations and the simulations. Extended-period events that overlap a short-term event generally have larger areas and longer durations compared to their counterparts with no overlapping short-term events. Understanding the climate dynamics yielding the two types of extended-period events could be useful for assessing future changes in the Missouri River Basin’s heavy precipitation events and their impact.

An evaluation of the landscape structure and La Niña climatic anomalies associated with Japanese encephalitis virus outbreaks reported in Australian piggeries in 2022

The widespread activity of Japanese encephalitis virus (JEV) reported in previously unaffected regions of eastern and southern Australia in 2022 represents the most significant local arbovirus emergency in almost 50 years. Japanese encephalitis virus is transmitted by mosquitoes and maintained in wild ardeid birds and amplified in pigs, the latter of which suffer significant reproductive losses as a result of infection. The landscape epidemiology of JEV in mainland Australia is almost entirely unknown, particularly in the eastern and southern parts of the country where the virus has not been previously documented. Although other areas with endemic JEV circulation in the Indo-Pacific region have demonstrated the importance of wild waterbird-livestock interface in agricultural-wetland mosaics, no such investigation has yet determined the composition and configuration of pathogenic landscapes for Australia. Moreover, the recent emergence in Australia has followed substantial precipitation and temperature anomalies associated with the La Niña phase of the El Niño Southern Oscillation. This study investigated the landscape epidemiology of JEV outbreaks in Australian piggeries reported between January and April of 2022 to determine the influence of ardeid habitat suitability, hydrogeography, hydrology, land cover and La Niña-associated climate anomalies. Outbreaks of JEV in domestic pigs were associated with intermediate ardeid species richness, cultivated land and grassland fragmentation, waterway proximity, temporary wetlands, and hydrological flow accumulation. This study has identified the composition and configuration of landscape features that were associated with piggery outbreaks reported in 2022 in Australia. Although preliminary, these findings can inform actionable strategies for the development of new One Health JEV surveillance specific to the needs of Australia.

Annual isotopic diet (δ13C) ofEremotherium laurillardi(Lund, 1842) and climate variation (δ18O) through the late Pleistocene in the Brazilian Intertropical Region

AbstractWe inferred the annual isotopic diet (δ13C) of an individual of the giant ground slothEremotherium laurillardifound in Toca dos Ossos (Ourolândia, Bahia, Brazil) through the extension of its third inferior molar. This individual lived in the region at 40,779–39,617cal yr BP. One year of its life was recorded in a length of 67 mm in the tooth. Two years were recorded in this molariform, during which the diet and climate did not change much, and substantial precipitation occurred during the middle of the year, which is in opposition to the modern pattern. The mean carbon (μδ13C = −13.9 ± 1.8‰) and oxygen (μδ18O = 22.5 ± 2.9‰) isotopic values were similar to values for other individuals of the species found in the same cave but different from the values found in other localities of the Brazilian Intertropical Region, which allows us to suggest that this region had more precipitation and lower temperatures in comparison to today. The oxygen isotopic values found in dated fossils ofE. laurillardiand from two other taxa found in the same cave (Toxodon platensis, andNotiomastodon platensis) could help in the understanding of the climatic variation that occurred in the region.