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Several damaging tropical cyclones (TCs) have occurred recently over the South Indian Ocean (SIO) region, causing enormous social and economic losses. Yet, while many studies have examined SIO TC characteristics using observations and reanalysis, only a few have assessed these characteristics specifically for this region in climate models, and fewer have investigated their projections under climate change. Here we do this for a historical (1980–2010) and future (2020–2050) period, using multimodel simulations from the High Resolution Model Intercomparison Project, as well as examine biases in the historical period relative to a reanalysis (ERA5). The models have horizontal resolutions of 25–50 km, which has enabled an improved ability to represent tropical cyclones globally in previous studies. TempestExtremes software is employed to detect tropical storm and cyclone tracks. In cases where TempestExtremes cannot be applied due to a lack of requisite variables in a dataset, we instead examine extreme wind speeds in that dataset. For the historical period, we find considerable variation in model biases compared to ERA5, which itself exhibits realistic spatial patterns of tracks and their monthly distribution. Models do at least agree on positive biases in track frequency east of Madagascar and somewhat in the Mozambique Channel. However, the models and ERA5 only produce Category 3 tropical cyclones at best. Wind speeds for 25 km resolution models have much larger positive biases than for 50 km ones, suggesting the former can simulate even higher‐category tropical cyclones. Considerable intermodel variation is also found in track changes between the future and historical periods. No systematic intercategory pattern of change exists, and low signal‐to‐noise may obscure any such patterns in the limited timespan of available data. Thus, no meaningful conclusions can be drawn regarding changes in track intensity. Nevertheless, track frequency broadly decreases across models for the region, as does accumulated cyclone energy. An east‐to‐west shift in track location from east of Madagascar toward the Mozambique Channel is also implied by track frequency and wind speed changes. Our findings provide information to potentially improve storm resiliency in this vulnerable region. [ABSTRACT FROM AUTHOR]

Cyclonic storms, or hurricanes, are expected to intensify as ocean heat energy rises due to climate change. Ecological theory suggests that tropical forest resistance to hurricanes should increase with forest age and wood density. However, most data on hurricane effects on tropical forests come from a limited number of well‐studied long‐term monitoring sites, restricting our capacity to evaluate the resistance of tropical forests to hurricanes across broad environmental gradients. In this study, we assessed whether forest age and aridity mediate the effects of hurricanes Irma and Maria in Puerto Rico, Vieques and Culebra islands. We leveraged functional trait data for 410 tree species, remotely sensed measurements of canopy height and cover, along with data on forest stand characteristics of 180 of 338 forest monitoring plots, each covering an area of 0.067 ha. The plots represent a broad mean annual precipitation (MAP) gradient from 701 to 4598 mm and a complex mosaic of forest age from 5 to around 85 years since deforestation. Hurricanes resulted in a 25% increase in basal area mortality rates, a 45% decrease in canopy height and a 21% reduction in canopy cover. These effects intensified with forest age, even after considering proximity to the hurricane path. The links between forest age and hurricane disturbances were likely due the prevalence of tall canopies. Tall forest canopies were strongly linked with low community‐weighted wood density (WD). These characteristics were on average more common in moist and wet forests (MAP >1250 mm). Conversely, dry forests were dominated by short species with high wood density (WD > 0.6 g cm−3) and did not show significant increases in basal area mortality rates after the hurricanes. Synthesis. Our findings show that selection towards drought‐tolerant traits across aridity gradients, such as short stature and dense wood, enhances resistance to hurricanes. However, forest age modulated responses to hurricanes, with older forests being less resistant across the islands. This evidence highlights the importance of considering the intricate links between ecological succession and plant function when forecasting tropical forests’ responses to increasingly strong hurricanes. [ABSTRACT FROM AUTHOR]

The National Science Foundation–sponsored Lake-Effect Electrification (LEE) field campaign intensive observation periods occurred between November and early February 2022–23 across the eastern Lake Ontario region. Project LEE documented, for the first time, the total lightning and electrical charge structures of lake-effect storms and the associated storm environment using a lightning mapping array (LMA), a mobile dual-polarization X-band radar, and balloon-based soundings that measured vertical profiles of temperature, humidity, wind, electric field, and hydrometeor types. LEE also observed abundant wind turbine-initiated lightning, which is climatologically more likely during the winter. The frequent occurrence of intense lake-effect storms and the proximity of a wind farm with nearly 300 turbines each more than 100 m tall to the lee of Lake Ontario provided an ideal laboratory for this study. The field project involved many undergraduate (>20) and graduate students. Some foreseen and unforeseen challenges included clearing the LMA solar panels of snow and continuous operation in low-sunlight conditions, large sonde balloons prematurely popping due to extremely cold conditions, sonde line breaking, recovering probes in deep snow in heavily forested areas, vehicles getting stuck in the snowpack, and an abnormally dry season for parts of the LEE domain. In spite of these difficulties, a dataset was collected in multiple lake-effect snowstorms (11 observation periods) and one extratropical cyclone snowstorm that clarifies the electrical structure of these systems. A key finding was the existence of a near-surface substantial positive charge layer (1 nC m−3) near the shoreline during lake-effect thunderstorms. SIGNIFICANCE STATEMENT: Winter lightning is an exciting phenomenon and important to study as man-made objects (e.g., wind turbines) can be more likely to be struck this time of year. We involved over 20 undergraduate students in collecting total lightning, mobile radar, and sounding (e.g., electric field) data in several lake-effect storms. These storms have been known to have substantial electrification and occur many times each winter in a small, consistent region east of Lake Ontario. We analyzed 246 lightning flashes from the main data collection period, and over a third of them were associated with towers. The results from this study will have impacts on our general understanding of electrification in winter and summer storms. [ABSTRACT FROM AUTHOR]

Societal Impact Statement: Conserving frankincense trees (Boswellia) is crucial for both ecological and socio‐economic reasons. Surveying these trees in the field and using remote sensing unmanned aerial vehicles in the Socotra Archipelago, we found that Socotran frankincense trees are threatened by forest fragmentation, overgrazing, and increasingly frequent extreme climate events. A better understanding of the distribution and the threats of these important insular species will improve the conservation policy of the local authorities and benefit local communities in the Socotra Archipelago. At the same time, this work serves as a good practice example to guide conservation efforts for other culturally important threatened tree species around the world, therefore helping to sustain local livelihoods, fostering ecological resilience, and supporting socio‐economic stability. Summary: Globally, frankincense trees (Burseraceae: Boswellia) are increasingly under threat because of habitat deterioration, climate impacts, and the olibanum trade. Despite harboring nearly half of the species in the genus, up‐to‐date insights are lacking for the insular endemic frankincense trees of the Socotra Archipelago UNESCO (United Nations Educational, Scientific and Cultural Organization) World Heritage Site (Yemen).We combined georeferencing of individual trees in the field with remote sensing applying unmanned aerial vehicles (UAVs) to evaluate Boswellia distribution and (sub)population sizes in the entire Socotra Archipelago.We counted 17,253 trees across all 11 taxa and we surveyed almost 55% directly in the field, collecting individual information on threats and health indicators. We estimate that the current total population sizes of the relatively common Socotran Boswellia taxa (Boswellia elongata, Boswellia popoviana, and Boswellia ameero) consist of a few thousand mature individuals with fragmented distribution of which a large proportion occurs in highly disjunct relictual stands, while the more range‐restricted species survive only through a few hundred (Boswellia nana and Boswellia samhaensis) to fewer than a hundred trees (Boswellia scopulorum). Our field data show that the Socotran frankincense trees are threatened by fragmentation and overgrazing resulting in a lack of natural regeneration, in combination with effects of extreme climate events (e.g., higher frequency and intensity of cyclones and prolonged drought) and potential future infrastructure developments; the species are less impacted by resin collection.We provide recommendations to strategize urgent protection of the declining Socotran frankincense trees, and we update their conservation status, resulting in an endangered status for seven and a critically endangered status for four taxa. [ABSTRACT FROM AUTHOR]

This study examines the experiences of 17 teacher candidates who participated in a literacy‐focused service‐learning initiative in the aftermath of destructive tornadoes in their community. In response to the natural disaster, the Literacy Ambassadors, composed of university literacy faculty and teacher candidates, sought to address the critical need for book access among area students impacted by the tornadoes. Over the course of 8 months, researchers collected initial questionnaires, participant reflections, meeting transcripts, and anecdotal notes as the group met to learn about book matching, text complexity, and to acquire, sort, and curate book bags for individual preK‐12 students. Books were shared with community members on three occasions—two occurred 12 months after the tornadoes and served eight schools; another occurred 16 months after the event and served one school. Participants revealed themes of shifting identity, a developing understanding of the complexity of literacy, and the relational power of literacy—offering valuable insights into the impact of community engagement on teacher candidates in response to disaster. These findings support previous research that emphasizes the potential of service‐learning as real‐life experiences that address community needs while simultaneously enriching the professional growth of future educators. [ABSTRACT FROM AUTHOR]

The North Indian Ocean (NIO) is one of the areas with the highest frequency of tropical cyclones (TCs) occurrence in the world. This study explores the spatial distribution patterns of North Indian Ocean tropical cyclone (NIOTC) trajectories and examines the relationship between the South Asian summer monsoon index (SASMI) and NIOTC using historical data spanning from 1959 to 2020. The annual average number of NIOTC is 4.92, with the highest frequency of occurrence being in the collection of cyclonic storms (34–47 kt) and severe cyclonic storms (48–63 kt). Based on the divergent and convergent trends in the interannual quantity sequences of SASMI and NIOTC, their relationship is categorized into two phases: positive and negative, each spanning 32 and 29 years, respectively. During the positive phase, the landfall frequency and the average intensity of TCs on the eastern coast of India are generally higher and the frequency of TCs' trajectories in the northeast Arabian Sea is significantly higher than during the negative phase, with an average difference of 19.13 trajectories within the range of 14°N-24°N and 61°E-73°E. While NIO is more inclined to generate stronger TCs during the positive phase, extremes are more likely to occur during the negative phase. [ABSTRACT FROM AUTHOR]

Using the statistical properties of the solution of the Fokker–Planck–Kolmogorov equation (FPK) for velocities and coordinates and using the vortex identification method, quantitative estimates of the distributions of various characteristics of cyclones and anticyclones (including lifetime, wind speed, size, characteristic forcing, and kinetic energy) depending on their intensity have been obtained. The calculations are based on ERA5 reanalysis data for the period 2010–2021. The vortex lifetimes estimated using the FPK correspond to the lifetimes obtained using the vortex identification method, and the theoretical distribution of cyclones by intensity practically coincides with those observed. The characteristics of vortices during their life cycle are also investigated. In general, all the characteristics of cyclones analyzed increase with their intensification. However, for intense anticyclones, the increase is not as pronounced as for cyclones. [ABSTRACT FROM AUTHOR]

Extratropical storms, particularly explosive storms or "weather bombs" with exceptionally high deepening rates, present substantial risks and are susceptible to climate change. Individual storms may exhibit a complex and hardly detectable response to human-driven climate change because of the atmosphere's chaotic nature and variability at the regional level. It is thus essential to understand changes in specific storms for building local resilience and advancing our overall comprehension of storm trends. To address this challenge, this study compares analogs—storms with a similar backward track until making landfall—in two climates of three explosive storms impacting different European locations: Alex (October 2020), Eunice (January 2022), and Xynthia (February 2010). We use a large ensemble dataset of 105 members from the Community Earth System Model, version 1 (CESM1). These analogs are identified in two periods: the present-day climate (1991–2001) and a future climate scenario characterized by high anthropogenic greenhouse gas emissions [representative concentration pathway 8.5 (RCP8.5), 2091–2101]. We evaluate future changes in the frequency of occurrence of the storms and intensity, as well as in meteorological hazards and the underlying dynamics. For all storms, our analysis reveals an increase in precipitation and wind severity over land associated with the explosive analogs in the future climate. These findings underscore the potential consequences of explosive storms modified by climate change and their subsequent hazards in various regions of Europe, offering evidence that can be used to prepare and enhance adaptation processes. Significance Statement: This study investigates the impact of climate change on explosive storms, or weather bombs, and their potential consequences for European regions. We project future scenarios of three specific storms, Alex, Eunice, and Xynthia, using a state-of-the-art climate model. Our findings reveal an increase in precipitation and wind over land associated with these storms, emphasizing the heightened risks associated with climate change. The significance lies in understanding the local implications of explosive storms, aiding in the development of resilient strategies and adaptation measures. [ABSTRACT FROM AUTHOR]

The propagation and dissipation of typhoon-induced surface waves are vital to morphological evolution and related engineering within coastal and estuarine regions. An observation system was operated during Typhoon Higos, and TELEMAC--TOMAWAC numerical modeling was performed for Typhoons Hagupit, Hato, and Higos along the central coast of Guangdong and the Pearl River Estuary in China to explore variations in wave propagation and dissipation during typhoons. The results showed that wind waves were dominant before typhoon landfall, and the intense wind waves dissipated rapidly during typhoon decay, while they could stay longer within the estuarine regions. Landward wave propagation had a tendency to convert from being convergence-dominated to being dissipation-dominated with the morphological change and tended to converge at the mouth-bar region. Within the estuarine regions, waves dissipated more rapidly at the prismatic estuary than at the bell-shaped bays due to the limited width and rapid contraction of the outlet. Moreover, the track and scale of typhoons had critical effects on the generated wave field, and they dominated the intensity, propagation, and dissipation of the overall wave field. Specifically, typhoons with broader scales and longer moving tracks within the coastal regions of Guangdong Province enhanced the wind--wave interaction and induced a stronger and wider wave field, despite that their typhoon intensities were comparable (i.e., Hagupit vs. Hato). Furthermore, waves generated by compact and regular cyclone structures dissipated more strongly along the moving track of typhoons (i.e., Hato and Higos). Except for typhoons directly attacking the Pearl River Estuary, waves within the estuarine regions tended to dissipate/converge when located on the right/left side of the moving track of typhoons. [ABSTRACT FROM AUTHOR]

Leveraging the Copernicus high‐resolution multi‐year Mediterranean Sea Surface Temperature (SST) dataset, 15 selected tropical‐like cyclones (TLCs) are analyzed with the objective of elucidating the anomalies of SST at the time of cyclogenesis and the connection between the change in SST during the cyclone lifetime and its characteristics. The long‐term SST increase associated with climate change is identified by comparing detrended and original anomalies. Detrending removes the effect of the intensification of SST anomaly over time, revealing that no significant anomalies generally emerge in the early stages of the TLC lifetimes. Conversely, winter events exhibit early‐stage positive SST anomalies. Also, high SST values were observed during the intensification of the most intense cyclones. A cold SST anomaly is left after the passage of the cyclones, due to the intense sea surface fluxes extracting heat from the sea. Plain Language Summary: Mediterranean tropical‐like cyclones are severe weather events able to produce large socio‐economic and environmental impact, as well as considerable damage. On average, 1.5 such events affect the Mediterranean each year. In this study we assess the Sea Surface Temperature conditions related to the events reported in the literature of the past four decades. We use a high‐resolution multi‐year SST dataset over the Mediterranean Sea, to reveal the potential relationship between the change in SST before and during the cyclone's lifetime and their features. Our results show that SST plays an important role in the intensification phases of the events, while no significant SST anomaly emerges in the early stages for most of the cyclones. Key Points: No significant SST anomalies are found at the early stage of medicanes, except for the winter cases that exhibit a positive anomalySST value is particularly high for the most intense cyclones (September cases)The passage of the cyclones over the sea induces a cooling mainly during their mature phase [ABSTRACT FROM AUTHOR]

Chang (2024, https://doi.org/10.1029/2024gl110011) challenged the methodology proposed recently by Okajima et al. for evaluating cyclonic and anticyclonic contributions to Eulerian eddy statistics and atmospheric energetics based on the local flow curvature. He argued that using the local wind curvature to separate energetic contributions from cyclones and anticyclones is not physically meaningful. Here we argue that his claims are based on an unrealistic assumption of monopolar relative vorticity in an entire storm‐track domain and a meridionally uniform zonal background flow atypical to midlatitudes. We also demonstrate that the error in attributing eddy statistics to cyclones and anticyclones is significantly smaller than his estimation. Rather, we further demonstrate that the curvature‐based methodology effectively eliminates the shear influence to identify cyclonic and anticyclonic regions, which is dismissed in his argument. We conclude that the curvature‐based methodology is beneficial in evaluating distinct cyclonic and anticyclonic contributions to atmospheric energetics in realistic conditions. Plain Language Summary: Chang (2024, https://doi.org/10.1029/2024gl110011) raised a question about the effectiveness of the recent method by Okajima et al. for evaluating cyclonic and anticyclonic contributions separately to eddy statistics based on the local flow curvature. He brings idealized cases to claim that the method by Okajima et al. is not physically meaningful. Here we show that Chang's arguments rely on an unrealistic assumption that an entire storm‐track region contains only one or two isolated cyclonic vorticity patches placed within horizontally uniform westerlies, which are atypical of midlatitudes. We also reveal that the error in attributing eddy statistics to cyclones and anticyclones is much smaller than Chang's result. The curvature‐based method effectively removes the influence of shear vorticity to determine cyclonic and anticyclonic regions, which is overlooked in his argument. We conclude that our curvature‐based method is useful for evaluating the separate contributions of cyclones and anticyclones to atmospheric energetics in realistic conditions in midlatitudes. Key Points: The error in attributing eddy statistics to cyclones and anticyclones is significantly smaller than that presented by Chang (2024, https://doi.org/10.1029/2024gl110011)The arguments of Chang (2024, https://doi.org/10.1029/2024gl110011) are based on the unrealistic assumptions of monopolar vorticity and an atypical background flowThe curvature‐based evaluation of cyclonic and anticyclonic contributions is a practical, beneficial method for realistic flow fields [ABSTRACT FROM AUTHOR]

Atmospheric energetics is frequently used to diagnose how different atmospheric processes contribute to the development of transient storm track activity. Okajima et al. (2024), https://doi.org/10.1029/2023gl106932 developed an ad hoc method to separate the contributions of cyclones and anticyclones to the energetics using the value of the curvature of the instantaneous local wind. Here, using simple examples in which the physics is exactly known, it is shown that cyclones embedded within a constant zonal flow exhibit large regions with anticyclonic curvature despite the absence of any real anticyclones. Using the method of Okajima et al., a large fraction of the eddy kinetic energy is erroneously attributed to being associated with anticyclones. Furthermore, the fraction that is misattributed varies substantially with changes in the background wind speed. It is concluded that using the curvature to separate energetics contributions from cyclones and anticyclones is not likely to be physically meaningful. Plain Language Summary: How different physical processes contribute to the development of cyclones and anticyclones is frequently diagnosed using the energy budget. Previous studies examined the combined contributions of cyclones and anticyclones to the budget terms. A recent study (Okajima et al., 2024, https://doi.org/10.1029/2023gl106932) developed an ad hoc method to use the value of the curvature of the instantaneous local wind to separate the contributions of cyclones from those of anticyclones. In this study, using idealized examples in which the physics is exactly known, it is shown that cyclones embedded within a constant zonal flow exhibit large regions with anticyclonic curvature despite the absence of any real anticyclones within the domain. In these examples, large fractions of the eddy energy can be misattributed as contributions from anticyclones based on the method of Okajima et al. In addition, the fraction that is misattributed varies substantially with changes in the background wind. It is concluded that it may not be physically meaningful to separate the energetics into contributions from cyclones and anticyclones separately. Key Points: The use of the curvature of the local wind to identify cyclones and anticyclones can lead to significant misattributionThe magnitude of the error varies substantially with changes in the background wind speed [ABSTRACT FROM AUTHOR]

Accurate subseasonal prediction of heavy rainfall is helpful for disaster mitigation but challenging. The land thermal condition of Tibetan Plateau (TP), usually with climate memory ranging from weeks to seasons, has been seen as a potential predictability source for subseasonal prediction. Aiming at 2020 record‐breaking Mei‐yu rainfall, this study attempts to investigate whether and how the influence of initial TP surface thermal condition near late June influences the July rainfall prediction over the Middle and Lower Yangtze River Region (MLYR), based on two contrasting prediction experiments using a global climate ensemble prediction system. The results show that the most distinguishable change in the downstream prediction in July is the anomalous low‐tropospheric cyclone and the associated increased rainfall over MLYR corresponding to the warmer initial condition of surface TP. Influenced by the invasion of the positive potential vorticity (PV) center that generated over TP and propagated eastward, this low‐level cyclone anomaly over MLYR is formed within the first week of prediction, and persists for the next 3 weeks maintained by the positive feedback between the low‐level cyclone and middle‐tropospheric latent heating over MLYR in the prediction. This study confirmed the significant effect of TP initial thermal condition on downstream prediction ahead of 3 weeks during the Mei‐yu season (peak summer) with strong land–atmosphere coupling over TP. Plain Language Summary: Based on two contrasting prediction experiments using a global climate ensemble prediction system, this study exhibits that changing the initial thermal condition over Tibetan Plateau (TP) surface can significantly influence the subseasonal prediction of rainfall over Middle and Lower Yangtze River Region (MLYR) in Mei‐yu season. After the TP land surface warming at the initial time of prediction, a low‐level cyclonic and increased rainfall appears within the first week of prediction and persists for the next 3 weeks maintained by the positive feedback between the low‐level cyclone and middle‐tropospheric latent heating over MLYR. This study confirmed the effect of initial land thermal condition over TP on the MLYR prediction ahead of 3 weeks during Mei‐yu season (peak summer) with strong land‐atmosphere coupling over TP. Key Points: Initial TP land surface warming can generate a local near‐surface PV positive center and expand downstream within the first prediction weekThe downstream cyclonic anomaly and increased rainfall can be maintained for 3 weeks in prediction by a positive feedbackThe study confirmed the effect of TP initial thermal condition on the MLYR prediction ahead of 3 weeks in Mei‐yu season (peak summer) [ABSTRACT FROM AUTHOR]

Tropical cyclones models have long used nesting to achieve higher resolution of the inner core than was feasible for entire model domains. These high resolution nests have been shown to better capture storm structures and improve forecast accuracy. The Hurricane Analysis and Forecast System (HAFS) is the new-generation numerical model embedded within NOAA's Unified Forecast System (UFS). The document highlights the importance of high horizontal resolution (2 km or finer) in accurately simulating the small-scale features of tropical cyclones, such as the eyewall and eye. To meet this need, HAFS was developed by NOAA leveraging a high-resolution, storm-following nest. This nest moves with the cyclone, allowing better representation of small-scale features and more accurate feedback between the cyclone's inner core and the larger environment. This hurricane following nest capability, implemented in the Finite-Volume Cubed-Sphere (FV3) dynamical core within the UFS framework, can be run both within the regional as well as global forecast systems. A regional version of HAFS with a single moving nest went into operations in 2023. HAFS also includes the first ever moving nest implemented within a global model which is currently being used for research. In this document we provide details of the implementation of moving nests and provide some of the results from both global and regional simulations. For the first time NOAA P3 flight data was used to evaluate the inner core structure from the global run. [ABSTRACT FROM AUTHOR]

Recent work has indicated that atmospheric radiative heating reduces the kinetic energy of large‐scale eddies in the midlatitudes. However, a physical mechanism that connects radiation to the midlatitude eddy kinetic energy is still uncertain. Using a high‐resolution general circulation model we perform an experiment in which the radiative cooling profile at each model time step is overwritten with the climatological mean, computed from a control simulation. This approach separates the mean and transient effects of radiative heating on the extratropical circulation. We find that, when radiative heating is fixed, the globally‐averaged eddy kinetic energy is enhanced by ∼6%. We show that thermal radiation dampens temperature anomalies near the surface and tropopause in low‐pressure systems, destroying eddy available potential energy and eddy kinetic energy. We identify this as a possible mechanism by which atmospheric radiative heating weakens midlatitude cyclones. Plain Language Summary: The atmosphere can be differentially heated through the absorption of visible and infrared radiation by water vapor and clouds. This process of radiative heating is thought to promote the formation of tropical cyclones, but its impact on midlatitude cyclones—storms characterized by the passage of warm and cold fronts—is less clear. Here we show that, unlike tropical cyclones, radiative heating weakens midlatitude storms. We argue that radiative cooling in the warm sector, and radiative heating in the cold sector of midlatitude cyclones, reduces the temperature gradient which is critical for the development of these weather systems. This study underscores an essential difference between tropical and midlatitude storms: in the tropics, temperature gradients are small, but at higher latitudes, temperature gradients are the drivers of storm formation. Key Points: When radiative interactions are suppressed, the global‐mean eddy kinetic energy increases by ∼6%Radiative cooling coincident with positive temperature anomalies destroys eddy available potential energy and eddy kinetic energyThe energetic perspective provides a useful way to understand the effect of radiative heating on the general circulation [ABSTRACT FROM AUTHOR]

The impact of assimilating in situ temperature, moisture and wind observations from a WindBorne Systems balloon, with long duration and adjustable ballast, is evaluated using a case study from the 2022 THINICE field campaign. A case is selected wherein the WindBorne balloon directly sampled a jet streak associated with a tropopause polar vortex (TPV). The observed TPV merged with another TPV at the same time as a downstream Arctic cyclone (AC) redeveloped eastward. The case is used to better understand the role of the observed TPV in the evolution of the downstream AC. The assimilation of the WindBorne observations improves the forecast track and amplitude of the TPV during the ∼1 day forecast period that the TPV can be tracked as a distinct feature. The root mean square error of temperature at 350 hPa is improved by the WindBorne assimilation throughout the 2.5 day forecast period. The surface cyclone track forecast is improved by the WindBorne assimilation during the period of eastward redevelopment of the surface cyclone, and the sea level pressure RMSE in the surrounding region is reduced during the first ∼1.5 days of forecast lead time. Results demonstrate the capability of the long‐duration controllable WindBorne balloons to improve the analysis of the TPV associated with the jet streak, leading to improved forecast of both tropopause‐level and surface pressure features. Additionally, the importance of observing the upstream TPV amplitude for improving forecasts of the process of TPV merging and its impact on the evolution and longevity of the mature AC is confirmed. Plain Language Summary: During a recent field campaign, WindBorne Systems deployed novel weather balloons that remain in the atmosphere for weeks at a time, adjusting their altitude to follow winds towards features of interest. These balloons provide an opportunity to study the impact of the merging of two upper‐level disturbances on the performance of an Arctic cyclone (AC) forecast. WindBorne observations of one of the two merged disturbances allowed for an improved forecast of the eastward redevelopment of the AC. These experiments confirm the importance of observing such features for AC prediction and the importance of the merging process in the maintenance and evolution of long‐lived Arctic cyclones. Key Points: WindBorne balloons can improve in situ sampling of small scale features critical for Arctic predictabilityTropopause polar vortex (TPV)‐related jet streak is important for predictability of subsequent TPV merging and Arctic cyclone (AC) redevelopmentMerging of TPVs without associated surface cyclone should be included in conceptual models of AC longevity [ABSTRACT FROM AUTHOR]

The evolution of Storm Ciarán was different from what is commonly attributed to windstorms affecting northwest Europe. Ciarán initially developed as a diabatic Rossby wave, driven by low‐level latent heat release and with negligible upper tropospheric forcing. It then crossed the jet stream, intensifying explosively while developing a low‐level warm seclusion and producing extreme near‐surface winds, including sting jets. Ciarán is an example of an extreme windstorm following this pathway and highlights the need of a systematic assessment of its relevance in our warming climate. [ABSTRACT FROM AUTHOR]

The article compares the storm that the Armada del Mar Océano suffered in 1672 with the Bernard storm of 2023, both affecting the southwest of the Iberian Peninsula with intense rains and strong winds. The Armada's storm was described as a "squall of the equinox", while Bernard was an extratropical cyclone that underwent a tropical transition in the eastern North Atlantic. Both storms had characteristics of a tropical cyclone, mainly affecting the Algarve region and lasting for approximately nine hours. [Extracted from the article]

Polar lows exhibit features with very sharp weather contrasts. In weather forecasting, a small misplacement of areas with hazardously high wind speeds can have fatal impacts for people living in polar regions. Therefore, a novel application of spatial verification methods for objective metrics of size, shape, and location of areas with hazardous weather is tested. To separate the effect of errors in polar low location and direction of motion from errors relative to the polar low centre, surface wind fields from the limited‐area weather forecasting model Applications of Research to Operations at Mesoscale‐Arctic and Copernicus Climate Change Service Arctic Regional Reanalysis are centred at the polar low centre and rotated according to the direction of background flow surrounding the polar low. Then the possibilities of the features‐based verification methods SAL (structure, amplitude, location) and MODE (Method for Object‐based Diagnostic Evaluation) are explored using a test case from October 2019. The study demonstrates that the methodology can provide valuable information about forecast performance. MODE is a flexible method with metrics that focus on characteristics of individual objects and can be adapted to questions at hand. For example, a measure of storm eye size was added. SAL, on the other hand, provides effective summary metrics for the full domain and proved particularly useful for evaluation of the overall distribution of wind speed. To evaluate the number of correctly or incorrectly identified areas with harsh weather rather than their details about their shape, contingency scores are more suitable. Applied to a larger dataset, this methodology can assess performance as a function of forecast length, as well as geographical area, and the type of polar low. The methodology can also be applied to other types of low‐pressure systems, such as extratropical cyclones. [ABSTRACT FROM AUTHOR]

The primary goal of the present paper is to examine variations in frequency and intensity of cyclonic storms over Arabian Sea using Accumulated cyclone energy (ACE) and Genesis Potential Index (GPI) from 1991–2020.For this purpose wavelet analysis is applied to surface and sub-surface ocean parameters viz Sea surface temperature (SST), Latent heat flux (LHF), Mixed layer depth (MLD), Depth of D26 Isotherm and Tropical cyclone heat potential (TCHP) to delve the probable changes. It is observed that the ACE signifies the intensity of tropical storms, has risen by 17.6% during the recent decade (2011–2020). LHF and SST are in phase with the intensification of cyclonic storms from Continuous wavelet transform (CWT) power spectrum analysis. Both SST and GPI were strongly correlated(0.8, 95% significant level) during pre-monsoon season.Siginifcant coherence was observed between frequency of cyclonic storms and TCHP in the recent decades through wavelet coherence transform technique. The cross wavelet transform (XWT) shows the frequency of cyclonic storms and SSTs are in phase during Indian Ocean dipole events. By these observations,this study helps in advance forecasting about formation and intensification of cyclonic storms over Arabian Sea. [ABSTRACT FROM AUTHOR]

Many fundamental concepts of synoptic-scale extratropical dynamics are based on the quasi-geostrophic equations of a dry atmosphere. This "dry dynamics" provides the essential understanding of, for example, the formation of extratropical cyclones and the propagation of Rossby waves and makes potential vorticity (PV) a materially conserved quantity. Classically, for extratropical weather systems, the importance of so-called "diabatic effects", e.g. surface fluxes, phase changes of water in clouds, and radiation, has been regarded as secondary compared to the dry dynamical processes. As outlined in this review article, research during recent decades has modified this view of the role of diabatic processes. A combination of complementary research approaches revealed that the nonlinear dynamics of extratropical cyclones and upper-tropospheric Rossby waves is affected – in some cases strongly – by diabatic processes. Despite the violation of material PV conservation in the presence of diabatic processes, the concept of PV has been of utmost importance to identify and quantify the role of diabatic processes and to integrate their effects into the classical understanding based on dry dynamics. This review first summarises the theoretical concepts of diabatic PV modification, moist PV, and slantwise moist convection and provides a concise overview of early research on diabatic effects until the late 1970s. Two poorly predicted high-impact cyclones affecting eastern North America then triggered an impressive diversity of efforts to investigate the role of diabatic processes in rapid cyclone intensification in the last 2 decades of the 20th century. These research activities, including the development of sophisticated diagnostics, growing applications of the Lagrangian perspective, real-case and idealised numerical experiments, and dedicated field experiments, are reviewed in detail. This historical perspective provides insight about how societal relevance, international collaboration, technical development, and creative science contributed to establishing this important theme of dynamical meteorology. The second part of the review then more selectively outlines important achievements in the last 2 decades in our understanding of how diabatic effects, in particular those related to cloud microphysics, affect the structure, dynamics, and predictability of different types of extratropical cyclones and their mesoscale substructures, upper-tropospheric blocks, Rossby waves, and interactions. A novel aspect is the relevance of research on diabatic processes for climate change research. The review closes by highlighting important implications of investigating diabatic processes in extratropical weather systems for the broader field of weather and climate dynamics and its fundamentals and representation in numerical models. [ABSTRACT FROM AUTHOR]

Cyclones are essential components of weather patterns in the densely populated Mediterranean region, providing necessary rainfall for both the environment and human activities. The most intense of them also lead to natural disasters because of their strong winds and heavy precipitation. Identifying sources of errors in the predictability of Mediterranean cyclones is therefore essential to better anticipate and prevent their impact. The aim of this work is to characterise the medium-range cyclone predictability in the Mediterranean. Here, it is investigated in a systematic framework using the European Centre for Medium-Range Weather Forecasts fifth-generation reanalysis (ERA5) and ensemble reforecasts in a homogeneous configuration over the 2001–2021 period. First, a reference dataset of 1960 cyclones is obtained for the period by applying a tracking algorithm to the ERA5 reanalysis. Then the predictability is systematically evaluated in the ensemble reforecasts. It is quantified using a new probabilistic score based on the error distribution of cyclone location and intensity (mean sea level pressure). The score is firstly computed for the complete dataset and then for different categories of cyclones based on their intensity, deepening rate, motion speed, and geographic area and season in which they occur. When crossing the location and intensity errors with the different categories, the conditions leading to poorer or better predictability are discriminated. The motion speed of cyclones appears to be crucial for the predictability of the location: the slower the cyclone, the better the forecast location. In particular, the location of stationary lows located in the Gulf of Genoa is remarkably well predicted. The intensity of deep and rapid-intensification cyclones, occurring mostly during winter, is for its part particularly poorly predicted. This study provides the first systematic evaluation of cyclone predictability in the Mediterranean and opens up possibilities to identify the key processes leading to forecast errors in the region. [ABSTRACT FROM AUTHOR]

Elliptic curve cryptography (ECC) is widely used for secure communications, because it can provide the same level of security as RSA with a much smaller key size. In constrained environments, it is important to consider efficiency, in terms of execution time and hardware costs. Modular inversion is a key time-consuming calculation used in ECC. Its hardware implementation requires extensive hardware resources, such as lookup tables and registers. We investigate the state-of-the-art modular inversion algorithms, and evaluate the performance and cost of the algorithms and their hardware implementations. We then propose a high-radix modular inversion algorithm aimed at reducing the execution time and hardware costs. We present a detailed radix-8 hardware implementation based on 256-bit primes in Verilog HDL and compare its cost performance to other implementations. Our implementation on the Altera Cyclone V FPGA chip used 1227 ALMs (adaptive logic modules) and 1037 registers. The modular inversion calculation took 3.67 ms. The AT (area–time) factor was 8.30, outperforming the other implementations. We also present an implementation of ECC using the proposed radix-8 modular inversion algorithm. The implementation results also showed that our modular inversion algorithm was more efficient in area–time than the other algorithms. [ABSTRACT FROM AUTHOR]

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Flow-type landslides are not typical in this region of the Balkans. However, after the Tamara cyclone event in 2014, numerous such occurrences have been observed in Serbia. This paper presents the initial results of a detailed investigation into debris flows in Serbia, comparing findings from two programs: RAMMS DBF and Geoflow SPH. Located in Western Serbia, the Selanac debris flow is a complex event characterized by significant depths in the initial block and entrainment zone. Previous field investigations utilized ERT surveys, supplemented by laboratory tests, to characterize material behavior. Approximately 450,000 m3 of material began to flow following an extreme precipitation period, ultimately traveling 1.2 km to the deposition zone. For validation purposes, ERT profiles from both the deposition zone and the source area were utilized, with particular attention given to areas where entrainment was substantial, as this had a significant impact on the final models. The first objective of this research is to conduct a detailed investigation of debris flow using field investigations: geophysical (ERT) and aerial photogrammetry. The second objective is to evaluate the capacity of two debris flow propagation models to simulate the reality of these phenomena. The GeoFlow-SPH code overestimated the maximum propagation thickness in comparison to the RAMMS model. The numerical results regarding final depths closely align, especially when considering the estimated average depth in the deposition zone. The results confirm the necessity of using multiple simulation codes to more accurately predict specific events. [ABSTRACT FROM AUTHOR]

The Sundarbans is the world's largest contiguous mangrove forest with an area of about 10,000 square kilometers and shared between Bangladesh and India. This world-renowned mangrove forest, located on the lower Ganges floodplain and facing the Bay of Bengal, has long served as a crucial barrier, shielding southern coastal Bangladesh from cyclone hazards. However, the Sundarbans mangrove ecosystem is now increasingly threatened by climate-induced hazards, particularly tropical cyclones originating from the Indian Ocean. To assess the cyclone vulnerability of this unique ecosystem, using geospatial techniques, we analyzed the damage caused by past cyclones and the subsequent recovery across three salinity zones, i.e., Oligohaline, Mesohaline, and Polyhaline. Our study also examined the relationship between cyclone intensity with the extent of damage and forest recovery. The findings of our study indicate that the Polyhaline zone, the largest in terms of area and with the lowest elevation, suffered the most significant damage from cyclones in the Sundarbans region, likely due to its proximity to the most cyclone paths. A correlation analysis revealed that cyclone damage positively correlated with wind speed and negatively correlated with the distance of landfall from the center of the Sundarbans. With the expectation of more extreme weather events in the near future, the Sundarbans mangrove forest faces a potentially devastating outlook unless both natural protection processes and human interventions are undertaken to safeguard this critical ecosystem. [ABSTRACT FROM AUTHOR]

This study explores the mechanisms contributing to heavy precipitation associated with landfalling atmospheric rivers (ARs) and orography, focusing on a high‐profile case study of an extratropical cyclone, storm Bronagh, which caused flooding and travel disruption in the UK. While prior research has established the connection between ARs, orography, and precipitation, the specific mechanisms leading to intense rainfall remain unclear. A novel methodology is introduced that quantifies the relative contribution to the total precipitation from cyclone‐induced processes and orographic processes using modifications to the Met Office Unified Model orography and microphysics parameterization scheme. Results show that the majority (63%) $(63\%)$ of storm Bronagh 's rainfall over land is attributed to cyclone‐related processes (frontal ascent and embedded convection). However, interaction of the AR associated with storm Bronagh and orography focuses more of the rain over the hills, enhancing precipitation in this region by a further 50% $50\%$. Further analysis reveals that the seeder‐feeder mechanism plays a predominant role in orographically enhanced rainfall. Accretion and riming processes occur as rain from the cyclone induced (seeder) cloud falls through the orographically induced (feeder) cloud enhancing precipitation rates. The feeder cloud formation is related to forced ascent of air within the AR over the orography. In conclusion, this study sheds light on the intricate interplay between ARs, orography, and cyclone precipitation during the landfall of extratropical cyclones. By separating the mechanisms behind heavy rainfall in the context of storm Bronagh, we quantify for the first time the effect of the seeder‐feeder effect at different heights over orography. Plain Language Summary: This study investigates why we experience heavy rainfall during storms in the UK. We focus on storm Bronagh which reached the national news because of the flooding and travel disruption it caused. While there is an established statistical link between atmospheric rivers, mountains, and rain, the details of how atmospheric rivers interact with mountains leading to intense rainfall were not well‐understood. In this research, a new approach which made adjustments to a weather model is used to determine these complex interactions. The results showed that most of the heavy rain during storm Bronagh came from the storm itself, but that it was enhanced via interaction with the mountains. The moisture in an atmospheric river turns into cloud droplets as it is forced to rise over the mountains. A specific process, allowing small raindrops to grow rapidly as they fall through orographic cloud, caused the localized rainfall enhancement. Understanding these processes helps us predict and prepare for extreme weather events better, enhancing our ability to respond to their impacts effectively. Key Points: The largest contribution to observed rainfall totals (63%) was associated with frontal ascent and convection in storm BronaghInteraction of storm Bronagh with orography enhanced rainfall totals by a further 50%Orographic rainfall enhancement in storm Bronagh is dominated by the seeder‐feeder process [ABSTRACT FROM AUTHOR]

In this study, the storm surge processes and characteristics of Tide-Surge Interactions (TSI) induced by the sequential tropical cyclones (TCs) BARIJAT and MANGKHUT (2018) in the Northern South China Sea (NSCS) are investigated using the numerical model. By comparing the impacts of the two TCs, we find that storm surges are significantly influenced by multiple factors. Notably, bays situated on the western side of the cyclone's landfall point exhibit a double peak pattern in storm surge. In addition, TSI exhibits a pronounced impact across bays affected by the two TCs, with amplitude fluctuations ranging from -0.3 to 0.3 meters and contributing approximately -5% to -20% to the peaks of storm surge. Comparative analysis of TSI variations reveals that tides act as the primary determinant, significantly influencing both the magnitude and period of TSI. Dynamic analysis further highlights that variations in TSI are dominated by barotropic pressure gradient and bottom friction stress. Moreover, TSI affects the frequency of storm surges, introducing high-frequency tidal signals to storm surges and reducing the frequency of storm surges. [ABSTRACT FROM AUTHOR]

The increase in natural disaster frequency, intensified by climate change, poses one of the greatest threats to coastal systems and low-lying areas worldwide. It is estimated that the Global Mean Sea Level (GMSL) could rise by approximately 2 m in the twenty-first century, alongside intensifying cyclonic events. Consequently, in Brazil, coastal natural disasters are likely to become more frequent and intense, especially in the southern region. Thus, this study aims to identify, map and discuss coastal natural disasters in municipalities exposed to the open ocean belonging to the coastal zone of Santa Catarina (SC), Brazil, between 1998 and 2020. A review and dating of coastal natural disasters were conducted using four official databases: The Civil Defense of Santa Catarina website, Integrated Disaster Information System (S2ID), Santa Catarina Atlas of Natural Disasters, and the Brazilian Atlas of Natural Disasters. The data were organized into spreadsheets and mapped using QGIS 3.16.0 software. The results and main conclusions indicate: (1) More coastal disasters occurred in the north, central-north, and central sectors of SC between 1998 and 2020; (2) the period between 2010 and 2020 was more impactful; (3) the municipalities with the most records of coastal disasters were Balneário Barra do Sul, Itapoá and Florianópolis (considering only Ilha de Santa Catarina), respectively; (4) the three fastest-growing sectors are the north, central-north, and central; and (5) the seasons of autumn, spring, and winter, respectively, are more impacting for the study area. [ABSTRACT FROM AUTHOR]

The occurrence of tropical cyclones (TCs) in the Horn of Africa and nearby areas is for the first time examined to document their contribution to local rainfall and their trends over the period 1990–2020. An average 1.5 TC (of any intensity) per year was observed over the Western Arabian Sea, with two asymmetrical seasons, namely May–June (30% of cyclonic days) and September–December (70%). Case studies reveal that in many instances, TC‐related rainfall extends beyond 500 km from the TC center, and that substantial rains occur one to 2 days after the lifecycle of the TC. Despite their rarity, in the otherwise arid to semi‐arid context characteristic of the region, TCs contribute in both seasons to a very high percentage of total rainfall (up to 30%–60%) over the northwestern Arabian Sea, the Gulf of Aden and their coastlines. Over inland northern Somalia, contributions are much lower. TCs disproportionately contribute to some of the most intense daily falls, which are often higher than the mean annual rainfall. A strong increase in the number of TCs is found from 1990 to 2020, hence their enhanced contribution to local rainfall. This increase is associated with a warmer eastern/southern Arabian Sea, a decrease in vertical wind shear, and a strong increase in tropospheric moisture content. Plain Language Summary: The role played by tropical cyclones in local rainfall in the Horn of Africa and nearby areas is for the first time examined. An average 1.5 cyclones (of any intensity) per year is observed over the Western Arabian Sea. They occur in two different seasons: May–June (30% of cyclonic days) and September–December (70%). Despite their rarity, these cyclones affect a region which displays arid to semi‐arid climates, hence they contribute to a very high percentage of total rainfall (30%–60%) over the northwestern Arabian Sea, the Gulf of Aden and their coastlines. Over inland northern Somalia, contributions are lower. Many of the most intense rainfall events are related to cyclones, with daily rainfall sometimes higher than the mean annual rainfall. There has been a strong increase in the number of cyclones from 1990 to 2020, and they contribute more to local rainfall. This increase is associated with a warmer Arabian Sea, a change in the wind flow and a higher moisture content. Key Points: An average 1.5 tropical cyclones occur annually in the Western Arabian Sea, 70% of them in September–December, the rest in May–JuneThey strongly contribute (30%–60%) to rainfall over the northwestern Arabian Sea, the Gulf of Aden and their coastlinesTheir frequency sharply increased from 1990 to 2020, resulting in a 11% rise of their contribution to the Gulf of Aden precipitation [ABSTRACT FROM AUTHOR]

Arctic cyclones are key drivers of sea ice and ocean variability. During the 2019–2020 Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition, joint observations of the coupled air‐ice‐ocean system were collected at multiple spatial scales. Here, we present observations of a strong mid‐winter cyclone that impacted the MOSAiC site as it drifted in the central Arctic pack ice. The sea ice dynamical response showed spatial structure at the scale of the evolving and translating cyclonic wind field. Internal ice stress and ocean stress play significant roles, resulting in timing offsets between the atmospheric forcing and the ice response and post‐cyclone inertial ringing in the ice and ocean. Ice motion in response to the wind field then forces the upper ocean currents through frictional drag. The strongest impacts to the sea ice and ocean from the passing cyclone occur as a result of the surface impacts of a strong atmospheric low‐level jet (LLJ) behind the trailing cold front and changing wind directions between the warm‐sector LLJ and post cold‐frontal LLJ. Impacts of the cyclone are prolonged through the coupled ice‐ocean inertial response. Local impacts of the approximately 120 km wide LLJ occur over a 12 hr period or less and at scales of a kilometer to a few tens of kilometers, meaning that these impacts occur at combined smaller spatial scales and faster time scales than most satellite observations and coupled Earth system models can resolve. Plain Language Summary: Arctic winter cyclones are an important part of the Arctic climate system. Yet, due to sparse observations, processes of the coupled sea ice‐ocean response to cyclones are not fully understood. During the 2019–2020 Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition, observations of the atmosphere, sea ice, and ocean were collected at a range of spatial scales. Here, we describe the atmospheric structure and coupled ice‐ocean response to a strong winter cyclone using data from surface weather stations, weather balloons, radar, and a weather model. We then describe the sea ice motion using a large set of global positioning system buoys and ice radar images. Finally, we examine the upper ocean currents and structure using ocean buoy data. The most important part of the storm structure for the sea ice is the development of an atmospheric low‐level jet (LLJ), a narrow region of fast‐moving air that eventually circles around the storm. The sudden change in ice drift speed at the time that the LLJ passes overhead enhances motion of the ice and ocean. Periodic currents in the ocean initiated by the sudden wind change of the LLJ continue for days following the passage of the storm, prolonging its effects. Key Points: A strong cyclone crossed the Multidisciplinary drifting Observatory for the Study of the Arctic Climate (MOSAiC) in midwinter 2020Detailed, multi‐platform observations enable characterization of coupled air‐ice‐ocean interactions during the passage of the cycloneThe development of a low‐level atmospheric jet is a key factor in the spatially and temporally varying sea ice‐ocean response to the storm [ABSTRACT FROM AUTHOR]

Viruses are abundant in the ocean and influence both the composition of marine communities and biogeochemical cycles. Despite their high abundance, production rates of distinct virus taxa in the environment are largely unknown. Here, we investigated production dynamics of T4-like cyanophages and compared them to those of the total dsDNA virioplankton community in two adjacent eddies of opposite polarity in the North Pacific Subtropical Gyre. Virioplankton production rateswere 3-fold higher in the cyclonic than in the anticyclonic eddy, potentially due to higher metabolic activity of their bacterial hosts in the cyclone, and had similar virus production rates during the day and night in the cyclone. In contrast, T4-like cyanophages had similar production rates in the two eddies but showed approximately 4-fold higher production rates at night than during the day, potentially due to a combination of greater infection, increased burst size and more cyanophages completing their infection cycle at night. These findings suggest that virioplankton community production is affected more by spatially differentiated environmental conditions while T4-like cyanophage production is more affected over the diel cycle. Differences in production for the T4-like cyanophages relative to the virioplankton community indicate that spatial variability at the mesoscale differentially impact distinct components of the virioplankton. [ABSTRACT FROM AUTHOR]

Previous studies suggested that the increase in surface chlorophyll a (Chl a) is due to nutrient upwelling or to the upward mixing of the subsurface Chl a maximum layer under the influence of tropical cyclones, while often ignoring the influence of the subsurface Chl a minimum layer and horizontal advection on Chl a. In this study, we show the important roles of the upward mixing of the subsurface Chl a minimum layer, horizontal advection, as well as the upwelling of the subsurface Chl a maximum layer, taking a looping super typhoon "Saola" in the northwest Pacific in August 2023 as an example. The temporal and spatial changes of Chl a and its physical properties were investigated by combining satellite, Argo, reanalysis, and model data. The results indicate that the combined effects of the upwelling of the subsurface Chl a maximum layer caused by wind stress curls and concurrent near‐surface wind mixing were responsible for the surface Chl a increase in the looping area during the typhoon, while the 13% increase in the depth‐integrated Chl a after the typhoon is mainly due to the nutrients brought by upwelling and subsequent biochemical processes. In the edge area affected by the typhoon, the surface Chl a decrease during the typhoon was mainly due to the upward mixing of the subsurface Chl a minimum layer (the effect of upwelling in this area is relatively weak). Furthermore, the horizontal advection led to a continuous surface Chl a decrease in the edge area after the typhoon. These findings could enhance understanding of Chl a dynamics post‐tropical cyclones, aiding marine ecosystem prediction. [ABSTRACT FROM AUTHOR]

To meet the Biden-Harris administration's goal of deploying 30 GW of offshore wind power by 2030 and 110 GW by 2050, expansion of wind energy into U.S. territorial waters prone to tropical cyclones (TCs) and extratropical cyclones (ETCs) is essential. This requires a deeper understanding of cyclone-related risks and the development of robust, resilient offshore wind energy systems. This paper provides a comprehensive review of state-of-the-science measurement and modeling capabilities for studying TCs and ETCs, and their impacts across various spatial and temporal scales. We explore measurement capabilities for environments influenced by TCs and ETCs, including near-surface and vertical profiles of critical variables that characterize these cyclones. The capabilities and limitations of Earth system and mesoscale models are assessed for their effectiveness in capturing atmosphere–ocean–wave interactions that influence TC/ETC-induced risks under a changing climate. Additionally, we discuss microscale modeling capabilities designed to bridge scale gaps from the weather scale (a few kilometers) to the turbine scale (dozens to a few meters). We also review machine learning (ML)-based, data-driven models for simulating TC/ETC events at both weather and wind turbine scales. Special attention is given to extreme metocean conditions like extreme wind gusts, rapid wind direction changes, and high waves, which pose threats to offshore wind energy infrastructure. Finally, the paper outlines the research challenges and future directions needed to enhance the resilience and design of next-generation offshore wind turbines against extreme weather conditions. [ABSTRACT FROM AUTHOR]

Climate change is associated with the modification of the polar jet stream, cyclone tracks and corresponding circulation patterns over midlatitudes. To apply these synoptic changes on regional climate, the changing sensitivity of a specific location to different pressure centre regions must be studied. An automated, objective circulation pattern detection method was developed to investigate the evolution of cyclonic and anticyclonic influence at any specific point within the European domain. The algorithm was used to assign each location to influencing low‐ or high‐pressure centres within the domain. Pressure centre displacements and the frequency redistribution among different centres were studied for each location. The 180‐year (January 1836–December 2015) mean sea level pressure dataset on the European domain with a 0.703° × 0.702° spatial and daily temporal resolution was obtained from NOAA 20th Century Reanalysis project. The presented method can apply the continental‐scale changes to specific locations. A significant increase of anticyclonic influence was found in southern and central Europe, in line with the northward displacement of Atlantic cyclones. Hundred and eighty year (180‐year) change of the number of days with anticyclonic versus cyclonic influence was found to be between +10% and 15% in the Mediterranean and +2% and 10% in most of Europe. The increasing anticyclonic influence in central Europe was strongest in the spring and the winter and was most attributable to the eastern European anticyclone. Results highlight the importance of research on the dynamical climate response of anticyclonic pressure systems. [ABSTRACT FROM AUTHOR]

This study utilized high-resolution numerical simulation data from the WRF model to conduct a thermodynamic diagnosis of the process by which Typhoon "Maysak" transformed and merged with the Northeast Cold Vortex. The results indicated that the continuous intrusion of cold vortex air and the relative cold advection formed by the typhoon's movement led to the demise of the typhoon's warm core structure. The low-level low-pressure convergence and upper-level high-pressure divergence structure disappeared. After the transformation and merging with the Northeast Cold Vortex, the cyclone became cold throughout the entire layer, with a cold center appearing at low levels. During the process of the typhoon's transformation and merging with the Northeast Cold Vortex, cold air accumulated near the low levels of the cyclone, causing the pseudo-adiabatic potential temperature lines to tilt and resulting in the slanted development of vertical vorticity in the mid-levels of the cyclone. After the typhoon transformed and merged with the Northeast Cold Vortex, the positive vertical vorticity advection at the bottom of the upper-level cold vortex trough promoted the cyclone's development directly from the mid-levels to the upper levels, while the jet stream at the bottom of the cold vortex trough facilitated the maintenance of the positive vertical vorticity advection. Concurrently, the thermodynamic shear vorticity parameter could describe the typical vertical structure characteristics of the dynamic and thermodynamic fields above the rain area during the typhoon transformation process. In terms of temporal evolution trends, there was a certain correspondence with the development and movement of the ground rain area, and the perturbation thermodynamic divergence parameter had a good indicative effect on the area of heavy rainfall. [ABSTRACT FROM AUTHOR]

The present study uses reanalysis data to investigate how the East Asian cold surges are linked to the initiation of westerly wind anomalies prior to El Niño events and easterly wind anomalies prior to La Niña events in the western equatorial Pacific. Our analysis shows that East Asian cold surge events can be associated with the formation of an anomalous anticyclone that moves eastward across the North Pacific and cools the ocean surface prior to El Niño events. The outflow of the anomalous anticyclonic circulation is responsible for the initiation of westerly wind anomalies in the western equatorial Pacific. We also find that East Asian cold surge events are involved in the development of an anomalous cyclone that moves northeastward along the subpolar North Pacific and reinforces the horizontal temperature gradient prior to La Niña events. The cross-equatorial flow into the anomalous cyclone in the North Pacific contributes to the development of easterly wind anomalies in the western equatorial Pacific. We show that air-sea interactions can play a role in the propagation of anomalous circulations across the North Pacific, eventually initiating zonal wind anomalies in the western equatorial Pacific. [ABSTRACT FROM AUTHOR]

This study evaluates the prediction of MJO teleconnections in two versions of the NOAA Unified Forecast System (UFS): prototype 5 (UFS5) and prototype 6 (UFS6). The differences between the two prototypes in the number of vertical layers (64 in UFS5 vs. 127 in UFS6) and the model top (54 km in UFS5 vs. 80 km in UFS6) can potentially impact the prediction of MJO teleconnections. With respect to ERA-Interim, the global teleconnections of the MJO to the Northern Hemisphere show similar biases in 500 hPa geopotential height over the North Atlantic and European sectors in both prototypes, whereas UFS6 has slightly smaller biases over the North Pacific region. Both prototypes capture the extratropical cyclone activity occurring in weeks 3–4 over the North Atlantic after the MJO phases 6–7 and over the North Pacific and North America after MJO phases 4–5. Both prototypes successfully forecast the sign and approximate locations of 2-m temperature anomalies over the mid-to-high latitude continents occurring in weeks 3–4 after MJO phase 3 but fail to capture the sign reversal of anomalies over North America between weeks 3 and 4 after MJO phase 7. Overall, the two prototypes show similar performance in simulating the tropospheric basic state as well as prediction skill of the MJO and MJO teleconnections, suggesting that the increase in model vertical resolution and model top does not strongly improve the prediction of MJO teleconnections in the troposphere in UFS. [ABSTRACT FROM AUTHOR]

This study delves into the intricate connection between Mainland Indochina Southwest Monsoon (MSWM) onset dates and tropical cyclones (TCs) over the Bay of Bengal (BOB) and Arabian Sea (ABMS). Utilizing datasets like International Best Track Archive for Climate Stewardship (IBTrACS), European Centre for Medium-Range Weather Forecasts Reanalysis data version 5 (ERA5), and Climate Hazards Group Infrared Precipitation with Station data (CHIRPS) daily rainfall data, the research highlights the influence of TCs on monsoon onset, emphasizing sea surface temperatures and rainfall intensity. The bimodal distribution of cyclones during early and late onset years is noted, during MSWM onset month May. Significant correlations emerge between cyclone frequency, monsoon onset dates, SST, and rainfall patterns. Employing a robust methodology, the study reveals a complex relationship between TCs and monsoon onset, with late-onset years experiencing higher TC numbers. Additionally, the research explores the influence of El Niño–Southern Oscillation (ENSO), associating positive phases with late monsoon onset and negative phases with early onset and increased rainfall. However, interestingly ENSO has less influence than the TCs over the monsoon onset process. And TCs dynamic may influence cut-out monsoon flow from formal circulation. The findings underscore TCs' multifaceted role in shaping the monsoon, offering insights into intricate climate variables and cyclone dynamics in the northern Indian Ocean. [ABSTRACT FROM AUTHOR]

Certain cyanide leaching tailings in Guizhou contain 1.66 g/t of gold, primarily existing in the forms of exposed gold and sulfide-encapsulated gold. The tailings have a high fineness, with particles of 0.038 mm accounting for over 80%. Given the high slime content of the cyanidation tailings, a sand-slime separation process was employed. Cyclones are used for grading and flotation is performed for the recovery of the underflow and overflow separately. A closed-circuit test with roughing once, scavenging twice, and cleaning three times was conducted, with process parameters and reagent regimes tailored to the characteristics of the underflow and overflow. The sand-slime separation process achieved a concentrate with a gold grade of 12.42 g/t and a gold recovery rate of 50.13%, while the ungraded flotation process of the cyanidation tailings produced a gold concentrate with a grade of 9.49 g/t and a recovery rate of 38. 10%. The results indicate that the sand-slime separation process improved the gold grade by approximately 2.9 g/t and the gold recovery rate by about 12 percentage points, effectively recovering gold from the cyanidation tailings. [ABSTRACT FROM AUTHOR]

This article presents the first photographic evidence of Tirumala hamata orientalis in Hong Kong. The butterfly was caught, photographed, and released in Pak Tam Chung. While the species is typically found in the Philippines, it has been observed as a vagrant in the Ryukyus and Taiwan. The sighting in Hong Kong may be due to dispersal from the Philippines. The article also explores potential host plants for the species and acknowledges the possibility of misidentification with a closely related species, T. limniace limniace. The authors hope that this publication will aid readers in distinguishing T. h. orientalis from other similar species in historical records and future observations. [Extracted from the article]

Post occupancy evaluation of housing reconstruction after a disaster is imperative for every nation that pushes ahead the idea of disaster resilient housing, which is obligatory for the social, cultural, and economic growth of a society or a country. Cyclone SIDR is the most dreadful of all catastrophes that have struck Bangladesh and aftermath of this devastation, a number of donor organizations stepped forward to help disaster victims by providing housing solutions. The aim of this study is to effectiveness analysis of these housing reconstruction programs from planning and construction standpoints with a post occupancy framework. Based on three months of detailed field survey at the most devastated location of cyclone SIDR, Southkhali Union (small rural area) of Sarankhola Upazila (sub-district) of Bagerhat District, this research infers that the donor organizations didn't pay much attention in terms of choice, need and indigenous practices to provide reconstructed houses for the target beneficiaries. The study found that about 78% of the reconstructed houses hold dissatisfaction of the beneficiaries. As a result, people prompt to transform or modify 54% of the 'Donor Driven' houses soon after completion of the project. Another 16% donor driven house remained abandoned and rest 8% demolished. On the other hand, 'Owner Driven' houses were functionally perfect. They had freedom to build their houses with locally available natural materials with resilient planning and construction features which reduces disaster vulnerability and sustains for long time in comparison with donor driven houses. [ABSTRACT FROM AUTHOR]

The implementation of the Variable Energy (VE) feature in the previously fixed-energy IBA Cyclone® Kiube cyclotron is presented as an upgrade enabling the production of novel radioisotopes with improved radionuclidic purity and production yields. The possibility of easily decreasing the energy of the extracted proton beam, from 18 down to 13 MeV, allows us to avoid the use of degraders and/or thick target windows, thus preventing related beam current limitations. The immediate application of the Variable Energy feature is proven by presenting the improved results obtained for the production of 68Ga from the irradiation of liquid targets simultaneously in terms of radionuclidic purity and activity produced. [ABSTRACT FROM AUTHOR]

Floods are highly destructive natural disasters. Climate change and urbanization greatly impact their severity and frequency. Understanding flood causes in urban areas is essential due to significant economic and social impacts. Hydrological data and satellite imagery are critical for assessing and managing flood effects. This study uses satellite images, climate anomalies, reservoir data, and cyclonic activity to examine the 2015 and 2023 floods in Chennai, Kanchipuram, and Thiruvallur districts, Tamil Nadu. Synthetic-aperture radar (SAR) satellite data were used to delineate flood extents, and this information was integrated with reservoir data to understand the hydrological dynamics of floods. The classification and regression tree (CART) model delineates flood zones in Chennai, Kanchipuram, and Thiruvallur during the flood years. The study region is highly susceptible to climatic events such as monsoons and cyclones, leading to recurrent flooding. The region's reservoirs discharged floodwaters exceeding 35,000 cubic meters per second in 2015 and 15,000 cubic meters per second in 2023. Further, the study examines the roles of the Indian Ocean Dipole (IOD), which reached its peak values of 0.33 and 3.96 (positive IOD), and El Niño in causing floods here. The complex network of waterways and large reservoirs poses challenges for flood management. This research offers valuable insights for improving the region's flood preparedness, response strategies, and overall disaster management. [ABSTRACT FROM AUTHOR]

In the transportation of grain particles, elbow wear is a pressing concern. A novel approach to mitigate this involves introducing a lateral air supplement rotation mechanism that enables swirling transportation. We assessed the integration of this device at angles of 45°, 55°, and 65° to the central axis of the main pipeline. While the multiphase flow velocity within the main conduit was held constant at 20 m/s, the lateral device's airflow velocities were tested at 20, 30, and 40 m/s. Utilizing the CFD–DEM simulation for grain particle transportation around bends, our findings indicated that an optimal arrangement was with the lateral device at 55° relative to the main pipeline, with an airflow speed of 30 m/s. This setup fostered a forward particle spiral, drastically diminishing wear on the pipe wall. Experimental evaluations corroborated the simulation's outcomes. [ABSTRACT FROM AUTHOR]

Cyclones are employed in many waste treatment industries for the dust collection or abatement purposes. The prediction of the dust collection efficiency is crucial for the design and optimization of the cyclone. However, this is a difficult task because of the complex physical phenomena that influence the removal of particles. Aim of the paper is to present two new meta-models for the prediction of the collection efficiency curve of cyclone separators. A Backpropagation Neural Network (BPNN) and Support Vector Regression (SVR) models were developed using Python environment. These were trained with a set of experimental data taken from the literature. The prediction capabilities of the models were first assessed by comparing the estimated collection efficiency for several cyclones against the corresponding experimental data. Second, by comparing the collection efficiency curves predicted by the models and those obtained from classic models available in the literature for the cyclones included in the validation dataset. The BPNN demonstrated better predictive capability than the SVR, with an overall mean squared error of 0.007 compared to 0.015, respectively. Most important, a 40% to 90% accuracy improvement of the literature models predictions was achieved. [ABSTRACT FROM AUTHOR]

This study examines the frequency of tropical cyclones in the Bay of Bengal and their impact on Bangladesh. The extent of environmental harm led to the selection of two specific areas: the Panpatty Union and Galachipa Upzilla in the Patuakhali district, and the Sariakat Union and Swandip Upzilla in the Chittagong district. The results indicate that cyclonic storms are more common in May and November. The results also demonstrate that the studied regions are vulnerable to the effects of tropical cyclones and suffer significant consequences. The differences in influence between the two locations are statistically significant with a confidence level of 90%. The findings have significant ramifications for policymaking decisions. [ABSTRACT FROM AUTHOR]

Atmospheric fronts embedded in extratropical cyclones are high‐impact weather phenomena, contributing significantly to mid‐latitude winter precipitation. The three vital characteristics of the atmospheric fronts, high wind speeds, abrupt change in wind direction, and rapid translation, force the induced surface waves to be misaligned with winds exclusively behind the cold fronts. The effects of the misaligned waves under atmospheric cold fronts on air‐sea fluxes remain undocumented. Using the multi‐year in situ near‐surface observations and direct covariance flux measurements from the Pioneer Array off the coast of New England, we find that the majority of the passing cold fronts generate misaligned waves behind the cold front. Once generated, the waves remain misaligned, on average, for about 8 hr. The parameterized effect of misaligned waves in a fully coupled model significantly increases the roughness length (185%), drag coefficient (19%), and air‐sea momentum flux (11%). The increased surface drag reduces the wind speeds in the surface layer. The upward turbulent heat flux is weakly decreased by the misaligned waves because of the decrease in temperature and humidity scaling parameters being greater than the increase in friction velocity. The misaligned wave effect is not accurately represented in a commonly used wave‐based bulk flux algorithm. Yet, considering this effect in the current formulation improves the overall accuracy of parameterized momentum flux estimates. The results imply that better representing a directional wind‐wave coupling in the bulk formula of the numerical models may help improve the air‐sea interaction simulations under the passing atmospheric fronts in the mid‐latitudes. Plain Language Summary: Atmospheric fronts are recurrent weather phenomena in mid‐latitudes, significantly contributing to winter precipitation. They are characterized by high wind speeds, abrupt changes in wind direction, and rapid translation. The passage of the fronts over the ocean can generate strongly misaligned waves with the local wind, particularly behind the cold fronts. The effects of these misaligned waves under atmospheric cold fronts on air‐sea fluxes remain undocumented. Using the long‐term surface observations from the Pioneer Array off the coast of New England, we find that the majority of the passing atmospheric fronts generate misaligned waves behind the cold front, which can remain misaligned, on average, for about 8 hr. By increasing the ocean roughness length in case of misaligned waves in coupled numerical experiments, a significant increase in momentum flux is found, which reduces the surface wind speeds. The misaligned wave effect is not accurately represented in a commonly used wave‐based air‐sea flux algorithm. Yet, by considering this effect in the current formulation, the overall accuracy of parameterized momentum flux estimates is improved. A better representation of the air‐sea interaction in numerical models is crucial for a better understanding of regional and global climate. Key Points: Passing atmospheric cold fronts generate a large area of growing wind‐waves that are misaligned with local windParameterized effect of misaligned waves increases the roughness length, drag and enthalpy coefficients, and wind stressRepresentation of the misaligned wave effect in the bulk formula improves the momentum flux estimates [ABSTRACT FROM AUTHOR]

Tropical cyclone causes large-scale devastation and destruction in the coastal plains of India, particularly in Odisha, which is the most cyclone-affected state in the country. Tropical cyclones are projected to be more powerful and widespread due to changing climate. Hence, the risk assessment of tropical cyclone is necessary to identify cyclone-risk areas in coastal Odisha which may help in the mitigation of the damages caused by cyclones. Therefore, this study utilizes geospatial techniques to produce a comprehensive risk map posed by tropical cyclones and to estimate the degree of risk for coastal districts of Odisha. For this, we evaluated the district-level cyclone risk for coastal Odisha using multi-criteria decision-making (MCDM) technique by considering 21 parameters for each of the four components of risk, i.e., exposure, hazard, vulnerability, as well as mitigation capacity. For each criterion, thematic raster map layers were created and weighted using a fuzzy analytical hierarchy process (FAHP). We prepared individual risk component maps using weighted overlay techniques and finally integrated all indices to create the risk map. The study shows that 13% area of the study area comes under a very high-risk zone whereas, 25% area comes under a high-risk zone. The central (Cuttack, northern parts of Khordha, and south-western parts of Jajpur district) and the eastern part (most of the parts of Jagatsinghpur, Kendrapara, and northern parts of Puri district) of the study area come under high to very high tropical cyclone impact zone. Almost 67% of the total area is highly vulnerable to tropical cyclones and mainly concentrated near the shoreline. The applied approach and results can assist the local authorities in identifying vulnerable and hazardous locations and developing workable solutions for the mitigation of revised cyclone threats in the coastal districts of Odisha. [ABSTRACT FROM AUTHOR]