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Moisture transport over the northeastern Atlantic Ocean is an important process governing precipitation distribution and variability over western Europe. To assess its long-term variability, the vertically integrated horizontal water vapor transport (IVT) froma long-term climate simulation spanning the period 850–2100CEwas used.Results show a steady increase in moisture transport toward western Europe since the late-nineteenth century that is projected to expand during the twenty-first century under the RCP8.5 scenario. The projected IVT for 2070–99 significantly exceeds the range given by interannual–interdecadal variability of the last millennium. Changes in IVT are in line with significant increases in tropospheric moisture content, driven by the concurrent rise in surface temperatures associated with the anthropogenic climate trend.Onregional scales, recent and projected precipitation changes over theBritish Isles follow the global positive IVT trend, whereas a robust precipitation decrease over Iberia is identified in the twenty-first century, particularly during autumn. This indicates a possible extension of stable and dry summer conditions and a decoupling between moisture availability and dynamical forcing. The investigation of circulation features reveals a mean poleward shift of moisture corridors and associated atmospheric rivers. In particular, in Iberia, a significant increase in the frequency of dry weather types is observed, accompanied by a decrease in the frequency of wet types.An opposite response is observed over the British Isles. These changes imply a stronger meridional north–south dipole in terms of pressure and precipitation distributions, enhancing the transport toward central Europe rather than to Iberia.

Atmospheric Rivers (ARs) are one of the key elements in explaining the occurrence of extreme precipitation and floods in mid‐latitudes. Despite the recognised importance of ARs, few studies have systematically evaluated how a weather forecast model captures AR conditions affecting western Europe. Using radiosonde observations from different sites across western Europe, this study evaluates the specific humidity, wind speed and moisture flux in the data assimilation system of the ECMWF Integrated Forecasting System (IFS) for the extended winter of 2020/2021 with a particular focus on landfalling ARs. Results indicate a systematic underestimation of specific humidity, wind and moisture flux in the IFS, particularly during more intense moisture flux events. The most significant negative biases of the IFS were observed in the boundary layer (1000–900 hPa) and lower free troposphere (900–700 hPa), coinciding with the core region of moisture flux. Wind speed was generally underestimated, with the largest errors occurring in the boundary layer at locations with complex topography. In addition, as expected, the assimilation of radiosonde profiles reduced short‐range forecast errors. The results highlight the current limitations in forecasting AR intensity and location and show the importance of in situ observations to improve the forecast of high‐impact weather events. Atmospheric Rivers (ARs) are major drivers of extreme precipitation and flooding in western Europe, yet forecasting their intensity and location remains challenging. Using radiosonde observations from multiple sites, we evaluated the ECMWF IFS data assimilation system during winter 2020/2021, focusing on specific humidity, wind and moisture flux. The system systematically underestimated these variables, particularly in the boundary layer and lower free troposphere, while assimilation of radiosondes improved accuracy, highlighting the importance of in situ observations for better prediction of high‐impact AR events.

An automated atmospheric river (AR) detection algorithm is used for the North Atlantic Ocean basin, allowing the identification of the major ARs affecting western European coasts between 1979 and 2012 over the winter half-year (October to March). The entire western coast of Europe was divided into five domains, namely the Iberian Peninsula (9.75° W, 36–43.75° N), France (4.5° W, 43.75–50° N), UK (4.5° W, 50–59° N), southern Scandinavia and the Netherlands (5.25° E, 50–59° N), and northern Scandinavia (5.25° E, 59–70° N). Following the identification of the main ARs that made landfall in western Europe, a Lagrangian analysis was then applied in order to identify the main areas where the moisture uptake was anomalous and contributed to the ARs reaching each domain. The Lagrangian data set used was obtained from the FLEXPART (FLEXible PARTicle dispersion) model global simulation from 1979 to 2012 and was forced by ERA-Interim reanalysis on a 1° latitude–longitude grid. The results show that, in general, for all regions considered, the major climatological areas for the anomalous moisture uptake extend along the subtropical North Atlantic, from the Florida Peninsula (northward of 20° N) to each sink region, with the nearest coast to each sink region always appearing as a local maximum. In addition, during AR events the Atlantic subtropical source is reinforced and displaced, with a slight northward movement of the sources found when the sink region is positioned at higher latitudes. In conclusion, the results confirm not only the anomalous advection of moisture linked to ARs from subtropical ocean areas but also the existence of a tropical source, together with midlatitude anomaly sources at some locations closer to AR landfalls.

Evaluating species responses to anthropogenic infrastructures and other habitat changes is often used to assess environmental impacts and to guide conservation actions. However, such studies are generally carried out at the population level, disregarding inter‐individual variability. Here, we investigate population‐ and individual‐level responses toward power lines of a territorial raptor, the Bonelli's eagle Aquila fasciata. We used GPS‐PTT tracking data of 17 adult eagles to model space use as a function of distance to transmission and distribution lines, while accounting for other habitat features known to affect this species. At population level, eagles increased the intensity of space use in the proximity of power lines (up to 1,000 m), suggesting an attraction effect. At individual level, some eagles shared the general population attraction pattern, while others showed reduced intensity of space use in the proximity of power lines. These differential responses were unrelated to the sex of individuals, but were affected by the characteristics of the power grid, with a tendency for apparent attraction to be associated with individuals occupying home ranges with a denser network of transmission lines and transmission pylons. However, the study could not rule out the operation of other potentially influential factors, such as individual idiosyncrasies, the spatial distribution of prey availability, and the availability of natural perches and nesting sites. Overall, these results suggest that power lines may drive different behaviors and have differential impacts across individuals, with those attracted to the proximity of power lines potentially facing increased risk of mortality through electrocution and collision, and those avoiding power lines being potentially subject to exclusion effects. More generally, our results reinforce the need to understand individual variability when assessing and mitigating impacts of anthropogenic infrastructures. We found power lines may drive different behaviors and have differential impacts across individuals. Our results reinforce the need to understand individual variability when assessing and mitigating impacts of anthropogenic infrastructures.

Africa faces significant challenges in reconciling economic and social development while preserving its natural resources. Little is known about the diverse bat community on the continent, particularly in drier ecosystems. A better understanding of the bat community will help improve and inform the management of these ecosystems. Our study aimed to provide detailed information on the main drivers of bat richness and activity at three different heights above the ground in a semi-arid region of Kenya. We assessed how bat activity varied with space and height using acoustic sampling and complementary methods. We sampled 48 sites at ground level and two sites on meteorological masts at 20 m and 35 m above the ground. We recorded more than 20 bat species, including one species of concern for conservation. Our models showed that the use of space varies with bat guild, creating trade-offs in the variables that affect their activity. Low-flying bat species are mostly associated with habitat variables, whereas high-flying species are more dependent on weather conditions. Our study highlights the richness of bat assemblages in semi-arid environments and emphasizes the need for management measures to protect bat diversity in the face of habitat degradation caused by climate change, land management, and development projects.

The European Macaronesia Archipelagos (Azores, Madeira and Canary Islands) are struck frequently by extreme precipitation events. Here we present a comprehensive assessment on the relationship between atmospheric rivers and extreme precipitation events in these three Atlantic Archipelagos. The relationship between the daily precipitation from the various weather stations located in the different Macaronesia islands and the occurrence of atmospheric rivers (obtained from four different reanalyses datasets) are analysed. It is shown that the atmospheric rivers’ influence over extreme precipitation (above the 90th percentile) is higher in the Azores islands when compared to Madeira or Canary Islands. In Azores, for the most extreme precipitation days, the presence of atmospheric rivers is particularly significant (up to 50%), while for Madeira, the importance of the atmospheric rivers is reduced (between 30% and 40%). For the Canary Islands, the occurrence of atmospheric rivers on extreme precipitation is even lower.

The present study assesses the thermal variability of the regional ocean around Madeira Island, in intraseasonal and interdecadal time scales, using a 35-year (1983–2017), 3-km horizontal resolution ocean simulation forced by a co-located atmospheric simulation, with SODA and ERA5 boundary and initial conditions, respectively. Atmosphere–ocean interactions in this region are found to be driven by the variability of two quasi-permanent tip-jets, located at the island west and east tips, especially during the summer months. The ocean response is found to be larger in the regions of higher jets speed variability, but its thermal response is highly asymmetrical. On the interdecadal time scale, a significant intensification of both jets during the analyzed period is more prominent in the east tip, but the thermal signature is mostly associated with a much reduced sea surface temperature trend near the west tip.

Atmospheric rivers (ARs) are long, narrow synoptic scale weather features important for Earth’s hydrological cycle typically transporting water vapor poleward, delivering precipitation important for local climates. Understanding ARs in a warming climate is problematic because the AR response to climate change is tied to how the feature is defined. The Atmospheric River Tracking Method Intercomparison Project (ARTMIP) provides insights into this problem by comparing 16 atmospheric river detection tools (ARDTs) to a common data set consisting of high resolution climate change simulations from a global atmospheric general circulation model. ARDTs mostly show increases in frequency and intensity, but the scale of the response is largely dependent on algorithmic criteria. Across ARDTs, bulk characteristics suggest intensity and spatial footprint are inversely correlated, and most focus regions experience increases in precipitation volume coming from extreme ARs. The spread of the AR precipitation response under climate change is large and dependent on ARDT selection. Plain Language Summary Atmospheric rivers (ARs) are long and narrow weather features often referred to as “rivers in the sky.” They often transport water from lower latitudes to higher latitudes typically across climate zones and produce precipitation necessary for local climates. Understanding ARs in a warming climate is challenging because of the variety of ways an AR can be defined on gridded data sets. Unlike weather features such as tropical cyclones where identification methodologies are similar, algorithms that determine the characteristics of ARs vary depending on the science question posed. Because there is no real consensus on AR identification methodology, we aim to quantify the algorithmic uncertainty in AR metrics and precipitation. We compare 16 different ways of defining an AR on gridded data sets and present the range of possibilities in which an AR could change under global warming. Generally, ARs are projected to increase but the amount of that increase is a function of the algorithm. Across all algorithms and focus regions, AR precipitation is projected to become more extreme. Key Points High‐resolution historical and future simulations are used to evaluate atmospheric river detection tools (ARDT) uncertainty ARDTs mostly show increases in frequency and intensity of future atmospheric rivers (ARs) but the scale of response is dependent on algorithmic restrictiveness Most regions experience an increase in precipitation volume coming from extreme ARs

An automated atmospheric rivers (ARs) detection algorithm is used for the North Atlantic Ocean basin that allows the identification and a comprehensive characterization of the major AR events that affected the Iberian Peninsula over the 1948–2012 period. The extreme precipitation days in the Iberian Peninsula and their association (or not) with the occurrence of ARs is analyzed in detail. The extreme precipitation days are ranked by their magnitude and are obtained after considering 1) the area affected and 2) the precipitation intensity. Different rankings are presented for the entire Iberian Peninsula, for Portugal, and for the six largest Iberian river basins (Minho, Duero, Tagus, Guadiana, Guadalquivir, and Ebro) covering the 1950–2008 period. Results show that the association between ARs and extreme precipitation days in the western domains (Portugal, Minho, Tagus, and Duero) is noteworthy, while for the eastern and southern basins (Ebro, Guadiana, and Guadalquivir) the impact of ARs is reduced. In addition, the contribution from ARs toward the extreme precipitation ranking list is not homogenous, playing an overwhelming role for the most extreme precipitation days but decreasing significantly with the less extreme precipitation days. Moreover, and given the narrow nature of the ARs, the location of the ARs over each subdomain is closely related to the occurrence (or not) of extreme precipitation days.

The climate of western Europe and northwest Africa strongly depends on the Azores anticyclone strength, location, and shape and, locally, also on the characteristics of the Iberia and Sahara summer thermal lows. EC-EARTH3 global simulations are here used to assess the predicted behaviour of these two relevant surface pressure systems and associated surface wind, by the end of XXI century (2071–2100), considering two climate change scenarios. Additionally, a high-resolution Weather Research and Forecasting (WRF) simulation centred on Madeira Island is used to assess the influence of climate change on the surface wind at smaller scales, in a region well known for its perturbed flows. Results indicate a general mean wind speed decrease over a sector of the North-Atlantic, associated with a flatter Azores anticyclone. However, the predicted intensification of the Iberia and Sahara thermal lows imposes an increasing surface wind speed near west Iberia and northwest Africa, in summer. Southwest of Iberia, Madeira Island is also predicted to experience a summer intensification of its tip-jets. The projected changes in low-level wind speed and variability will impact on different sectors of activity, either directly as are the cases of aeronautical operation and offshore renewable energy, or indirectly through changes in the ocean circulation.