bluuebunny/crossref_metadata_2025 huggingface dataset:
Stakeholder relevant hazard indices in Euro-CORDEX models developed under the EU- Impetus4Change project
Authors: Outten Stephen , Raffaele Francesca , Zazulie Natalia , Vandeskog Silius Mortensønn
Published: July 2024

Europe suffers great financial loss and loss of life to extreme events every year, and while the impacts of these events may increase due to society’s increasing exposure, the hazardous events themselves are also expected to change. The accurate projection of the changes in extreme events is invaluable for many industries, including insurance, construction, and energy, but also for those stakeholders responsible for preparing the European cities to withstand future extreme events. However, such adaptation requires information that is tailored to the needs and workflow of the stakeholders.
In the EU-Impetus4Change (I4C) project, we have worked with stakeholders in four demonstrator cities across Europe to select hazard indices that are directly applicable to their ongoing work in adapting to climate change. The cities, Barcelona, Paris, Prague and Bergen, were selected because they represent a wide range of climates across Europe and face different hazardous events. There are 23 indices in total, which focus primarily on heat waves and extreme rainfall, but also include indices on drought, fire weather, and river discharge. These indices have now been calculated in 67 models from the EURO-CORDEX simulations, covering all of Europe for the period of 1980 to 2100. These indices are analyzed for both their changes over the timeseries but also at Global Warming Levels of 1, 1.5, 2, 3, and 4 degrees. In this talk we will present a description of the indices and show the first analysis of selected indices for the European domain. The full dataset of these indices is planned to be made openly available through an online, user-friendly toolkit as part of the I4C project.
Analysis of Triggering Mechanisms for Localized Nocturnal Convection Over a Complex Mountainous Region in South China and Sources of Forecast Errors in the Convection-Permitting Model
Authors: Rao Xiaona , Zhu Kefeng , Zhao Kun , Chen Xingchao
Published: July 2024

The concave mountainous area of Pearl River Delta is a summer rainfall hotspot along the South China coast due to the presence of warm-moist monsoon flow and complex orography. This study evaluated the performance of a convection-permitting Weather Research and Forecasting (WRF) model in forecasting nocturnal rainfall in this area, focusing on days with low level southwesterly winds during the summers of 2013–2015. Results showed that the nocturnal rainfall exhibited two centers, one located along the large-scale northern mountains and the other along the small-scale Huadu Hill. WRF demonstrated superior performance in predicting rainfall over the northern mountainous region. In contrast, WRF significantly underestimated nocturnal rainfall both near local Huadu Hill and in the foothill area of northern mountains, which were strongly influenced by local forcings. Using high-resolution analyses from Variational Doppler Radar Analysis System (VDRAS), which assimilated both Doppler radar and Automatic Weather Stations observations, we firstly investigated the mesoscale mechanism governing the convection initiation (CI) of a typical localized nocturnal convection. Results showed that the enhanced prevailing low-level southerly winds, combined with local circulation induced by the urban heat island effect and orographic forcings, led to the formation of low-level convergence and strong updrafts before CI. Subsequently, we identified the sources of forecast errors in triggering CI. Results revealed that WRF severely underestimated thermal contrast between the Guangdong-Hong Kong-Macao Greater Bay Area urban agglomeration and the concave mountains, leading to the absence of the northeastern/northern inflows toward the cities. Consequently, low level convergence and updrafts near the CI position were too weak to lift air parcels above the severely overestimated level of free convection, thereby failing to trigger the convection.VDRAS-based sensitivity experiments, with a specific focus on assimilating surface temperature, validated the crucial role of urban-mountain thermal contrast on local winds that triggered the nocturnal convection.This study underscores the significance of urban-mountain thermal contrast and local circulations in determining nighttime precipitation formation and prediction, particularly in geographically complex regions characterized by concave mountains and urban agglomerations. The findings highlight the need for improved representation of these local forcing mechanisms in numerical weather prediction models to enhance their accuracy in forecasting nocturnal rainfall events.
SUNSET: SUbseasoNal to decadal climate forecast post-processIng and asSEssmenT suite
Authors: Pérez-Zanón Núria , Agudetse Victòria , Palma LLuis , Ho An-Chi , Delgado-Torres Carlos , Milders Nadia , Duzenli Eren , Llabrés-Brustenga Alba , de Paula Kinoshita Bruno , Bretonnière Pierre-Antoine , G. Muñoz Ángel
Published: July 2024

Climate services that rely on the provision of climate forecasts at sub-seasonal, seasonal or decadal time scales (S2S2D) are widely exploited these days. To make them helpful for decision-making, state-of-the-art climate forecast model outputs are tailored to user needs. The conjunction of scientific knowledge and scientific exploration to fulfil users' needs determines the post-processing workflow, from selecting the datasets to visualising the product. Consequently, scientists need to perform different combinations of possible workflows to evaluate the quality of the final products, ensuring the results are meaningful and that best practices (such as cross-validation strategies) are followed. For instance, essential climate variables (ECVs) can be calibrated before computing an indicator, or the indicator based on ECVs could be calibrated instead. Furthermore, several combinations of forecast systems and observation-based datasets can be explored to provide the most convenient product. On the other hand, the required computational resources can be a limitation depending on the total data size involved in the post-processing workflow.To efficiently and flexibly handle all the requirements when exploring and delivering climate services based on S2S2D predictions, the Earth Sciences department of the Barcelona Supercomputing Center has developed the SUbseasoNal to decadal climate forecast post-processIng and asSEssmenT suite, so-called SUNSET. This suite takes advantage of existing software packages and tools (such as startR, CSTools, s2dv, CSDownscale and Autosubmit) to facilitate the definition of the workflow and its parallelisation on HPC machines when available.To tailor climate products for each application and sector (e.g. agriculture, energy, water management, or health), the scientist can decide on the post-processing required steps, such as region selection, regridding method and resolution, anomaly calculation, and downscaling and bias-adjustment methods. SUNSET also allows the creation and visualisation of climate forecast products, such as maps for the most likely tercile. It performs the verification of the products using deterministic and probabilistic metrics, which can be visualised with maps and summarised with scorecards. The storage of final numerical outputs is also designed to consider the need to be ingested by third-party applications or impact models.SUNSET is available in a public repository licensed under the GPLv3 license, and it is under continuous development. The suite is being used in scientific projects such as CERISE, where the next generation of the Copernicus Climate Change Service seasonal climate forecasts are under development.
Long-term responses to changes in Arctic soil hydrology
Authors: García-Pereira Félix , González-Rouco Jesús Fidel , Meabe-Yanguas Nagore , Jungclaus Johann , de Vrese Philipp , Lorenz Stephan
Published: July 2024

Global warming is particularly intense in the Arctic, where temperature trends are up to four times higher than those observed globally. This results in Arctic permanently frozen soils, known as permafrost, being particularly vulnerable to climate change. Permafrost degradation due to warming is a critical element for Earth's climate stability, as it leads to the release of substantial amounts of carbon into the atmosphere, acting as a positive feedback mechanism for climate change. Additionally, the permafrost retreat leads to changes in the landscape, loss of resources, and damage to infrastructure, posing an economic challenge for populations inhabiting the Arctic. However, the increase in temperatures is not the only factor affecting permafrost degradation. Changes in water availability in the Arctic, induced by decadal and centennial changes in general atmospheric circulation, significantly alter soil moisture and the presence of ice, and thus the thermal structure of the soil in permafrost regions. This, in turn, may have global feedbacks through Arctic Amplification processes.The representation of Arctic hydrological and thermodynamical processes and their interactions is still limited in current ESMs, hindering the understanding of Arctic permafrost dynamics. This work explores the response of the Max Planck Institute for Meteorology's ESM (MPI-ESM) to changes in hydrological and thermodynamic characteristics of its Land Surface Model, JSBACH, in permafrost-affected regions. A set of ongoing experiments covering the past2k (0-1850), the historical period (1850-2014), and different climate change scenarios (SSPs, 2015-2100) with variations in soil depth and vertical resolution under two hydro-thermodynamic coupling configurations generating comparatively drier or wetter conditions in the Arctic allows for assessing climate sensitivities to Arctic hydroclimate.
STRAHLGRID - A solar radiation model with applications across different spatial scales
Authors: Seitner Vanessa , Göbel Matthias , Schlögl Matthias , Olefs Marc
Published: July 2024

High-resolution information on short wave radiation fluxes and sunshine duration is important for a wide range of applications in the context of energy and mobility transition, sustainable energy planning and climate change adaptation.We present a comprehensively refactored and updated version of the solar radiation model STRAHLGRID. The broadband model is used to compute diffuse and direct solar radiation on both horizontal and real (inclined) surfaces, as well as the sunshine duration in a spectral range of 0.3-3 μm covering Austria‘s national territory. Model output is available on a near-real-time basis with a temporal resolution of 15 minutes and a spatial resolution of 100 x 100 meters. The model takes atmospheric turbidity, cloudiness and terrain shading into account. For an accurate representation of temporal variations in atmospheric turbidity, precipitable water and visibility fields from the nowcasting model INCA are included. Terrain characteristics (elevation, aspect, slope, horizon angle and sky view factor) are derived from a digital elevation model that has been aggregated to a spatial resolution of 100 m. Model validation was conducted using quality controlled global solar radiation and sunshine duration data from 178 automatic weather stations in Austria as well as gridded reanalysis data sets. Comparisons with station data, COSMO REA 6 and CERRA reanalysis showcase the benefits of STRAHLGRID.The model is used to provide input for modelling tasks on different temporal and spatial scales (e.g., combination with airborne laser scanning data to incorporate local shading effects) and to derive products related to solar energy applications (longterm means and variability).  This presentation covers the conceptual framework behind STRAHLGRID as well as the methods used for modelling, and offers insights to validation and usage of the dataset. The dataset is accessible through the GeoSphere Austria DataHub (https://data.hub.geosphere.at/) at daily resolution.  
Significant slope change but insignificant correlation change between heatwaves and blocking under future global warming
Authors: Chan Pak Wah , Zhang Jilin , Catto Jennifer , Collins Matthew
Published: July 2024

Extra-tropical continental summer heatwaves often occur under persistent anticyclones or blocking.  Here, we study the heatwave–blocking relation under future global warming projected by CMIP6 SSP585 experiment.  We define both recent-past and future heatwaves using detrended temperature anomalies and recent-past thresholds.  We employ an optimized blocking index that best correlates with heatwave frequency (Pearson correlation of 0.7).  The index is from Dole and Gordon 1983, which identifies persistent positive geopotential anomalies. With detrended temperature and recent-past thresholds, we find a significantly steepened (flattened) heatwave–blocking slope over Europe (Greenland) under future global warming.  The steepened heatwave–blocking relation over Europe could be a result of depleted soil moisture and enhanced land–atmosphere coupling, which enhance the capacity of blocking in driving more heatwaves.  The flattened heatwave–blocking relation over Greenland is likely because the melting of ice or snow and the absorption of latent heat, which limit blocking’s capacity in driving heatwaves.  Considering the contribution to heatwave frequency change, the heatwave–blocking slope change likely dominates over decrease in blocking frequency.  Despite the statistically significant change in heatwave–blocking slope, we find statistically insignificant change in heatwave–blocking correlation.  In other words, the ratio of heatwave variability explained by blocking will not change significantly.  We also find the same type of blocking found in the recent past, i.e., identified with the same amplitude threshold and duration threshold, continues to be most relevant to future heatwaves.  We revisit previous evidences that suggest future heatwaves being caused by different circulation patterns, in order to understand more about the reasons behind the apparent discrepancy.  Studies on future heatwave frequency should focus on the heatwave–blocking relation change, and the thermodynamical factors behind. 
The citizen science project Co-Carbon Trees Measurement: quantifying the CO2 captured by urban trees
Authors: Mazon Jordi , Jaumà Artemi
Published: July 2024

One of the big challenges that the EU has proposed is the mission of 100 cities to become carbon neutral by 2030, and the whole continent by 2050. One of the key points to know is how many CO2 can capture the whole urban tress in a year. This amount of absorption depends on several parameters (type of tree, age, water requirement, …), being weather conditions during the whole year the most relevant. The amount of CO2 captured by a tree can be estimated by using different models. The method and equation proposed by Shadman et al. (2022) has been used in the Co-Carbon Trees Measurement project. This is a citizen science project developed in several cities in the metropolitanean area of Barcelona. The results of the pilot developed in the city of Viladecans (67.000 inhabitants, 15 km south to Barcelona) is presented. In this project more than 700 student measured around 1300 trees in a morning, which data allow to take a magnitude of the carbon captured by the 20.000 trees in the city, and so to know how far is the city to become, a carbon neutral. The project proposes repeat yearly this measurement in the same trees, to calculate the CO2 captures in a year, and to link with some annual meteorological parameters like average temperature and precipitation. Shadman, S., Khalid, P. A., Hanafiah, M. M., Koyande, A. K., Islam, M. A., Bhuiyan, S. A., … & Show, P. L. (2022). The carbon sequestration potential of urban public parks of densely populated cities to improve environmental sustainability. Sustainable energy technologies and assessments, 52, 102064.   
Sea surface wind measurement enhanced by stepped frequency microwave radiometer: A comprehensive approach to validation and sensitivity analysis
Authors: Kang Deok-du , Kim Min-seong , Han Seung-beom , Goo Tae-young , Jung Sueng-pil , Lee Gwang-jae , Shin Jong-hoon , Kang myeong-hoon
Published: July 2024

The National Institute of Atmospheric Sciences (NIMS) employs its KingAir 350H research aircraft for various missions, including the "Severe Weather" (SW) mission. This mission aims to enhance understanding of severe weather events like heavy rain, snowfall, and typhoons through advanced observations, ultimately improving numerical model accuracy. A key instrument aboard the aircraft is the Stepped Frequency Microwave Radiometer (SFMR). Mounted underneath, this C-band radiometer measures ocean brightness temperature to calculate sea surface wind speed and rain rate. Our study compared wind speeds derived from the SFMR with those obtained from dropsondes deployed along the aircraft's flight path. We also investigated the sensitivity of SFMR wind speed estimates to sea surface temperature and salinity, both serving as initial input data. Between 2021 and 2023, 118 SW-mission flights around the Korean peninsula. SFMR data revealed an average wind speed of 8.7 m/s and a maximum of 22.1 m/s. Sea surface temperature and salinity data from buoys and research stations were interpolated to 0.1˚ intervals for sensitivity analysis. Calibration coefficients derived from a dedicated calibration flight on October 26, 2022, were applied to re-calculate wind speeds, which were then compared with pre-calibration estimates and wind speeds obtained from dropsondes at 30m, 150m, and 500m above the sea surface. Notably, the strongest correlation was observed between SFMR-derived wind speeds and those at 500m. This study demonstrates the potential of NIMS aircraft SFMR data for accurate sea surface wind speed measurements, particularly when employing calibration and considering the influence of lower-level wind patterns. Further research can refine these techniques and enhance our understanding of air-sea interaction.
A high density observational dataset of daily meteorological data for the Extended Alpine Region
Authors: Bongiovanni Giulio , Matiu Michael , Crespi Alice , Napoli Anna , Majone Bruno , Zardi Dino
Published: July 2024

Several observational products of key climate variables have been widely used to evaluate the extent of the ongoing effects of climate change in the Alpine area, one of the most vulnerable and sensitive regions to the continuous warming of climate. However, a limited spatial coverage in most observational products and quality issues of data may strongly impact climate and hydrological studies results in terms of reliability, accuracy and precision. Even though the collection and management of meteorological data for the whole Alpine area is a challenging task due to strong fragmentation and diversity of data sources, further efforts need to be dedicated to produce new harmonised, high-quality and high-resolution products able to permit a more robust assessment of climate change and its impacts.  Here we present a new observational dataset gathering in-situ daily measurements of key climate variables provided by a variety of meteorological and hydrological services within the extended Alpine region. Data collected are recorded up to 2020, with a temporal extent of about 200 years in the longest time series. The observational network consists of about 10000 in-situ weather stations, resulting in an extended and homogeneous coverage, both in space and elevation. Data collected are screened, inspecting the presence of most important critical issues in terms of data quality. A deep quality control of collected time series has been performed by checking internal, temporal and spatial consistency of time series, exploiting the problem of outlier removal. Data homogeneity was assessed by a cross-comparison of results obtained with Climatol, Acmant and RH Test methods. Quantile matching was used to adjust inhomogeneous periods in time series. The present dataset addresses the most important issues affecting state-of-the-art observational products and it represents a powerful tool for better understanding Alpine climate changes over the last decades and improving the reliability of future scenarios.
Reasons for Different Predictability of Tropical Cyclone Tracks in the Western North Pacific and Atlantic Oceans
Authors: Zhou Feifan , Ye Yiwei
Published: July 2024

Recent several studies have focused on the predictability of tropical cyclone track forecast. As a response to the question issued by Landsea and Cangialosi (2018) about "the approaching limit of predictability for tropical cyclone (TC) track prediction is near or has already been reached", Zhou and Toth (2020) (short for ZT20) and Yu et al. (2022) (short for Y22) have found that the limit of predictability for TC track prediction has not been reached both in Atlantic (ATL) and Western North Pacific (WNP) basins. However, the predictabilities are different in two basins, as ZT20 found that 1 day's improvement can be obtained through 10 years in ATL, while Y22 found that 2 days' improvement can be obtained through 15 years in WNP. To reveal the causes of this difference, the predictability of TC track in WNP is first investigated under the same framework as ZT20. Then important parameters that determined the predictabilities are found and analyzed. Results suggested that the growth rate of true track forecast error in WNP is higher than that in ATL, indicating a lower predictability in WNP. Further explorations suggested that TCs in WNP basin have averagely larger sizes, stronger intensities, lower-latitude locations, and poorer forecast skills of their guided flows. All these factors contribute to the larger track forecast error growth rate. Moreover, it is pointed out that as the improvement of forecast skills over years mainly due to the reduction of initial analysis errors, although a lower predictability is found in WNP, the forecast skill improvement in WNP is faster than that in ATL.
Refinement of coupling strength between soil moisture and latent heat flux: Effects on medium-range weather forecast and soil moisture data assimilation in the KIM system
Authors: Gim Hyeon-Ju , Koo Myung-Seo , Kwon Yonghwan , Cho Mee-Hyun , Song Jaeyoung , Jun Sanghee , Kim Wonheung , Seol Kyung-Hee , Kwon In-Hyuk
Published: July 2024

The Korean Integrated Model (KIM), an operational global numerical weather prediction model at the Korea Meteorological Administration, has been developed during the initial phase of the Korea Institute of Atmospheric Prediction Systems (KIAPS) from 2011 to 2019. During this phase, the Noah land surface model (LSM) has been coupled to KIM, and the initial states of the land surface are being generated by a land data assimilation (DA) system based on the National Aeronautics and Space Administration (NASA) Land Information System (LIS). In the ongoing second phase of KIAPS from 2020 to 2026, the Noah-Multiparameterization (Noah-MP) LSM, designed to enhance geophysics representations, has been integrated into the KIM system and is currently undergoing further geophysical advancements.This study examines the interaction between land surface and atmosphere in the KIM system by estimating a coupling strength between soil moisture (SM) and latent heat flux (LH) represented in LSMs. It is found that improved SM initial conditions through land DA do not ensure improving forecast fields of temperature and specific humidity in the low troposphere in some regions, particularly South Asia croplands, where typically the SM and LH coupling strength is overrepresented in LSMs. Notably, among the sub-components of LH, direct evaporation at the soil surface exhibits stronger coupling with SM than other sub-components. As the overrepresented SM and LH coupling strength may cause degraded performance of land SM DA within land-atmosphere coupled systems, here we aim to analyze and improve the SM and LH coupling representations in LSMs towards improving land DA of the KIM system. In this presentation, we will introduce the sensitivity experiments on LH-related parameters and their impacts on the SM DA performance as well as medium-range weather forecasts.Acknowledgements. This work was carried out through the R&D project “Development of a Next-Generation Numerical Weather Prediction Model by the Korea Institute of Atmospheric Prediction Systems (KIAPS)”, funded by the Korea Meteorological Administration (KMA2020-02212).
A quantitative explanation for the different Impacts of El Niño Development and Decay Stages on the Hadley Circulation
Authors: Feng Juan , Ji Xuanliang , Li Jianping , Chen Xingrong , Wang Chunzai
Published: July 2024

The impact of El Niño on the Hadley Circulation (HC) has been a topic of previous studies, but the results have been inconclusive. We study how El Niño affects the HC during different stages of its cycle. In development years, the HC anomaly shows an equatorial quasi-symmetric pattern, while in decay years, it shows an asymmetric pattern. And it is shown a transition in the variability of the first two modes of the HC during these stages, with the first mode exhibiting a larger explained variance in the decaying stage. The regime change in HC variability corresponds to underlying anomalous SST distributions, as confirmed by sensitive experiments. The differences in tropical SST during different stages of El Niño cause differences in SST meridional gradients, which determine the location of convergence. This explains why the HC anomalies have different spatial structures during El Niño development and decay years. Quantitative assessment reveals stronger HC-SST response amplitudes during the decaying stage compared to the development stage. Employing the Kuo-Eliassen (KE) equation, diabatic heating anomalies during the decaying stage explain the difference in air-sea response intensity between the two stages. Diabatic heating variations are identified as the primary contributor to amplification or reduction of air-sea response intensity during the respective El Niño stages, providing insights into the different air-sea processes throughout the El Niño lifespan. Our results show that the meridional distribution of SST during different El Niño stages has significantly distinct impacts on meridional circulation and clarify the differences in El Niño's effects on climate.
The connection between sea surface temperature anomaly over tropical south Atlantic and ENSO and the associated impact on East Asian climate
Authors: Liu Yimin , Zhang Shaoyu , Ma Tingting , Sheng Chen , Dong Buwen
Published: July 2024

The tropical Atlantic, as a vital component of the tropical oceans, exerts significant influence on both local and global climates through its sea surface temperature variability and interactions among tropical basins. We found a significant influence of the sea surface temperature anomaly over tropical south Atlantic (TSA-SSTA) on ENSO Events and the Meiyu onset date. A significant negative correlation between the preceding TSA-SSTA and subsequent summer ENSO events was revealed. The warm (cold) TSA-SSTA corresponds to the following summer La Niña (El Niño)-like SSTA in the tropical Pacific. Warm TSA-SSTA can trigger local anomalous upward motion, resulting in precipitation and positive Walker circulation anomalies in the equatorial Pacific. This configuration facilitates the strengthening of easterly anomalies in the lower level of the equatorial Pacific, further promoting the development of La Niña-like SSTA in the central to eastern equatorial Pacific. These mechanisms and conclusions remain valid even after linearly removing the signal of the preceding winter ENSO. At the same time, when TSA-SSTA is warm the Meiyu onset date tends to be early. This is because that warm TSA-SSTA triggers significant positive Gill responses in the equatorial Pacific, further generating local anticyclonic circulation anomalies over the Maritime Continent of the northwest Pacific. Under the combined effects of large-scale forcing and the "precipitation-circulation Sverdrup positive feedback" mechanism in the northwest Pacific, anomalous anticyclones can develop and be sustained, resulting in an earlier Meiyu onset date. Furthermore, the interannual relationship between the TSA-SSTA and ENSO also exhibits decadal variability, closely related to the Pacific Decadal Oscillation (PDO).
Assessment of WRF-LES Model Performance in Simulating Valley Breezes and Vertical Structure of the Planetary Boundary Layer in the Pyrenees.
Authors: Carbone Juan , Ortiz-Corral Pablo , Román-Cascón Carlos , Yagüe Carlos
Published: July 2024

A modeling study of a real case has been conducted to assess the performance of the large-eddy simulation version of the Weather Research and Forecasting Model (WRF-LES) in the Vallée d'Aure region, situated on the northern side of the Pyrenees.This study aims to evaluate the model's ability to accurately simulate thermally-driven flows (TDF) and the vertical thermal and dynamic structure of the planetary boundary layer (PBL). This is essential because the characteristics of TDFs at mountain environments are influenced by factors such as the strength of the temperature gradient near the surface, interaction with winds of varying spatiotemporal scales, such as synoptic winds, and the vertical structure of the pre-existing PBL.The accurate simulation of turbulence in the PBL at sub-kilometer horizontal scales is a complex issue, but it offers advantages under stable conditions and over heterogeneous surfaces when local properties are required or when resolving small-scale surface features is desirable, as is the case of the valley here considered. To evaluate the performance of methods currently available in the WRF-LES model, different sensitivity experiments are conducted with different PBL treatments.To validate these simulations, data from the MOSAI1 field campaign, conducted in collaboration with the LATMOS-i2 and WINDABL3 projects, have been used. Throughout this campaign, meteorological radiosoundings were performed, and three meteorological stations were strategically installed in the valley, incorporating surface turbulence measurements. (1) MOSAI project (Model and Observation for Surface-Atmosphere Interactions, https://mosai.aeris-data.fr/).(2) LATMOS-i project (Land-ATMOSphere interactions in a changing environment: How do they impact on atmospheric-boundary-layer processes at the meso, sub-meso and local scales in mountainous and coastal areas?) (PID2020-115321RB-I00, funded by MCIN/AEI/ 10.13039/501100011033).(3) WINDABL project (PR2022-055). Project to impulse the career of young researchers funded by the University of Cádiz (Spain) (Plan Propio).
Analysis of the 10-years daily observation of homogenitus clouds in Catalonia (2014-2024).
Authors: Costa Marcel , Escoda Jordi , Mazon Jordi , Pino David , Ripoll Ricard , Del Amo Xènia
Published: July 2024

In 2014 the Catalan Weather Service started in some of the weather observatories in Catalonia the systematic daily observation of clouds caused by human activities (Mazon et al., 2012), the homogenitus clouds defined by the WMO in 2017 (https://cloudatlas.wmo.int/en/homogenitus.html ). It was a pioneer initiative that aimed to account by direct observations the contribution of human activities to the cloud cover. After 10 years of systematic observations, a daily homogenitus clouds observation database has been built in one of these observation locations, la Selva del Camp observatory (located near 100 km south to Barcelona city). By using this datase, two analysis have been performed. The first one has been a statistical analysis, focused on the high homogenitus clouds, caused by aircrafts. The analysis has been done at different temporal scale, from daily, to annual and interannual, which allows us to quantify the average percentage of cloud cover by high clouds produced by aircrafts (contrails), and the annual and seasonal trend within this period. The second analysis focusses on those days with contrails covering more than 2 and 3 octas. A synoptic and temperature analysis has been done at sea level, 850 and 500 hPa of geopotential height during the previous days and the day of the peak of the anthropic clouds, which allows to stablish the relationship between extreme events of high anthropic clouds and geopotential height at 850 and 500 hPa.     Mazón, J., Costa, M., Pino, D. and Lorente, J. (2012), Clouds caused by human activities. Weather, 67: 302-306. https://doi.org/10.1002/wea.1949
CMIP6 climate projections based wave energy production analysis for Mutriku Wave Energy Plant in the XXI century
Authors: Carreno-Madinabeitia Sheila , Serras Paula , Ibarra-Berastegui Gabriel , Sáenz Jon , Ulazia Alain
Published: July 2024

Nowadays, the number of operational renewable energy plants is steadily increasing. It is necessary to analyse how climate change might affect their energy production.  Motivated by this need, this study analyses the Mutriku Wave Energy Plant, which has been operating since July 2011 and has a total capacity of 296 kW.ECMWF Reanalysis v5 (ERA5) data and Commonwealth Scientific and Industrial Research Organisation (CSIRO) wave climate projections are used between 2015 and 2100. The projections are derived from two CMIP6 models: ACCESS-CM2 and EC-EARTH3, along with their respective parameterizations CDFAC1.08 and CDFAC1. Specifically, we employ six different climate projections, two based on the low-emission SSP1-2.6 scenario and four based on the higher-emission SSP5-8.5 scenario.Bias correction for vector-valued variables are performed using the multivariate bias technique based on the MBC N-pdf bivariate pdf, while for univariate variables; the classical Quantile Mapping (QM) technique is applied. Additionally, the self-organising map, SOM, technique is also used to classify the daily frequencies and powers of sea type. Finally, the Smirnov test is employed to assess if the shapes of the probability distributions from the different datasets differed statistically. A significance level of 0.05 is used.Our results show that wave energy production in the Bay of Biscay remains stable in the 21st century. This stability is reflected in a significantly way in the analysis of sea type frequencies and in the energy production. This consistent wave scenario ensures reliable and predictable energy generation, making the Bay of Biscay a valuable source of renewable energy both now and in the future.
Observed bioclimatic changes across the protected area network of Finland 
Authors: Aalto Juha , Lehtonen Ilari , Pirinen Pentti , Aapala Kaisu , Laurila Terhi K. , Gregow Hilppa , Heikkinen Risto K.
Published: July 2024

In boreal regions, trends in biologically relevant climate variables (i.e., bioclimate) over protected areas (PAs), important for biodiversity, have largely remained unquantified. Here, we investigated the changes and variability of 11 bioclimatic variables of both seasonally-integrated variables and extreme-events across Finland during the period 1961–2020 using a gridded climatology. Our results highlight significant changes in growing season temperature over the entire study area, whereas, e.g., annual precipitation sum and April–September water balance have increased especially in the central and northern parts of Finland. Moreover, we found substantial spatial variation in bioclimatic variables over the 631 studied PAs describing e.g. snow conditions and number of frost days in spring with absent snow cover, reflecting the changing exposure of biota to frost. The observed increases in accumulation of heat in the southern boreal zone and more frequent rain-on-snow events in the northern boreal zone can be important for the drought tolerance and winter survival of species, respectively. A multivariate ordination analysis suggested that the main dimensions of bioclimate change in PAs vary by vegetation zones. For example, in the southern boreal zone the changes are mostly related to annual and growing season temperatures, whereas in the middle boreal zone the changes are related to altered moisture and snow conditions. Our findings underpin the marked spatial variation in bioclimatic trends and climate vulnerability in northern Europe. The large suite of bioclimatic indicators provides new understanding of how climate change is manifesting over the northernmost Europe with sensitive ecosystems, and helps to develop biodiversity conservation and ecosystem management. 
High-resolution observations of a gravity wave event over the Netherlands 
Authors: Knoop Steven , Assink Jelle , Tijm Sander , Leijnse Hidde
Published: July 2024

Atmospheric gravity waves (GW) are small-scale propagating disturbances that arise due to the vertical forcing of air parcels by topography, convection, wind shear, jet streams, frontal systems and other tropospheric sources. GWs play a key role in the transfer of energy, and produce turbulence when they dissipate. This can lead to clear air turbulence (CAT) at higher altitude layers, which is a risk for aviation. GWs can be trapped in the lower atmosphere, propagating only horizontally, in which they can impact the state of the atmosphere. Knowledge about heavy waves (and turbulence) in the boundary layer is still limited and contributes to uncertainties in weather and climate models.Here we present observations of a strong GW event in the night and early morning of June 30, 2022. The GWs were generated by outflow from a frontal system over the North Sea and Belgium, and reached a large part of the Netherlands. Several wave trains travelled over the Netherlands, with similar direction but distinct phase speed and wavelength. This event was captured by many sensors that are part of the KNMI observational network. From our weather radars, automatic lidar ceilometer and surface observation network the GW propagation properties are determined.  At our Cabauw supersite, part of the Ruisdael Observatory, Doppler lidar and microwave radiometer measurements provide detailed insight in the vertical profiles of the passing GWs. They show fundamental mode ducted GWs, trapped in the lower 500 m with a vertical velocity amplitude up to 3 m/s. Above this altitude, the waves are evanescent and are observed to decay with height. The Doppler lidar also allows us to observe GW-generated turbulence and derive vertical profiles of eddy dissipation rate, due to its high temporal resolution of 1s. Finally, the 200-m mast in-situ observations highlight the influence of the GWs on the meteorological variables, showing large amplitude oscillations in pressure, temperature, relative humidity, wind speed and wind direction.This comprehensive set of observations may serve as a testbed for high resolution weather models that aim to capture these type of GW events. As this work also highlights the ability to detect GWs by the different components of our KNMI observational network, it provides a starting point to further explore the occurrence and properties of these GWs in the Netherlands, including the North Sea. 
Climate change fingerprint on the 2023 Emilia Romagna floods
Authors: Ginesta Mireia , Lu Chen , Coppola Erika , Yiou Pascal , Faranda Davide
Published: July 2024

The region of Emilia Romagna in northeastern Italy, with its capital in Bologna, experienced a sequence of flooding events on May 2nd, 10th, and 16th, 2023. These three events were linked to the passage of three extratropical cyclones, identified as Mediterranean cyclones, over the same region within a short period. We investigate the influence of climate change on each of these cyclones using an Extreme Event Attribution framework.We use the analogues approach to identify similar cyclones in two periods characterized by weak and strong climate change. Cyclones are defined using a multivariate method based on sea level pressure, surface wind speed, and precipitation rate. We first normalize the fields via quantile normalization. We then calculate the spatially averaged Euclidean distance between the cyclones and other time steps within the phase space defined by the normalized sea level pressure, wind speed, and precipitation rate. Analogues are identified as those with the minimum Euclidean distance.We assess detected changes using daily ERA5 reanalysis data, comparing the meteorological hazards of the analogues of the past period (1950–1985) with the present (1987–2022). To evaluate future changes, we conduct a multi-model study with high-resolution regional models within the EURO-CORDEX program, comparing historical (1970–2000) with future projections (2070–2100). We found an increase in precipitation associated with two of the cyclones during the present period compared to the past. Future projections also indicate an increase in precipitation compared to the present climate. Hence, our findings suggest a possible role of climate change in increasing the severity of such cyclones.
Turbulence anisotropy in unstable stratified flows over hills: an idealized large eddy simulation study
Authors: Wójcik Damian , Stiperski Ivana
Published: July 2024

Turbulent characteristics of the atmospheric surface layer are considered to be well understood over flat and horizontally homogeneous terrain. There, their initial description was provided by the Monin and Obukhov Similarity Theory (MOST; 1954) and fine-tuned using data from targeted observational campaigns (e.g., Businger et al., 1971). Since then, MOST has served as the basis for parameterization of turbulent exchange in numerical models and for processing of near-surface weather observations. Over complex heterogeneous terrain, however, classical MOST is not applicable due to violation of its underlying assumptions, and has been shown not to work. The recent work of Stiperski and Calaf (2023) has offered a way forward for turbulence parametrizations over non-ideal terrain, and has shown that MOST can be improved if the degree of turbulence anisotropy of the Reynolds stress tensor is included as an additional nondimensional parameter. From practical point of view, this raises a demand to parameterize the turbulence anisotropy over complex terrain for a possibly wide range of boundary-layer conditions.The current study uses large eddy simulation technique to explore the impact of infinite sinusoidal topography on turbulence anisotropy in neutral and unstably stratified flows. The parameter range explored covers a range of hill heights and length scales, as well as geostrophic winds speeds, while the simulations are initialized with a constant surface heat flux. Simulations are carried out using the pseudo-spectral NCAR model with terrain-following coordinates (Sullivan et al., 2014).  The hill height is kept low due to the incompressible nature of the flow. As the model utilizes the MOST itself at the lower boundary, the simulations require very high-resolution to resolve a wide fraction of the inertial-range. Moreover, turbulence statistics are explored at a distance from the surface.
Understanding impact weather: insights from the Basque Country
Authors: Gaztelumendi Santiago , Egaña Joseba , Ruiz Miriam
Published: July 2024

Extreme weather and climate events have profound effects on societies, economies, and environments worldwide. As a result, meteorological and hydrological service providers and researchers are increasingly considering factors such as hazard, exposure, and vulnerability in order to gain a comprehensive understanding of the full impact of weather and to contribute to minimizing fatalities and losses, thus enhancing resilience. Implementing these goals involves various technical and methodological approaches and numerous challenges in developing effective operational products and services.In the case of the Basque Country, as in other parts of the world, improving the resilience of our societies against weather impacts is a current priority and will become increasingly important in the future due to the potential local increase in severe weather events and exposure. As a first step in this complex process of characterizing weather impacts, accurate information from past events must be collected, prepared, and maintained. To this end, a severe weather catalogue has recently been implemented, focusing on local weather impacts, to record detailed information about severe or adverse weather events that affect our society. This catalogue serves as a repository of valuable information for characterizing and evaluating extreme weather events and its consequences.In this contribution, we present an in-depth study of severe weather events that have occurred in our territory during this century, including an analysis of the associated environmental conditions and their impacts. The main objective of this work is to enhance our understanding of local weather impacts by examining synoptic and local hydro-ocean-meteorological conditions conveniently correlated with the degree of impact. We analyze different key aspects aggregated by season, event typology, hazard type, and other relevant factors. Throughout this work, we present and discuss statistical findings to provide perspective and characterize the main aspects of the common hazards and impacts experienced by our territory. Dealing with impact, various indicators are defined and categorized to characterize key aspects, including severe weather warning levels, economic damages, human fatalities, or disruptions to normal life.
Land use and soil texture effects on WRFv4.3 
Authors: Bravo Manel , Mercader Jordi , Moré Jordi
Published: July 2024

In meteorological models, land use and soil texture play a key role in determining surface variables, as they intervene in the exchange of energy, moisture and momentum between the land and the air. In recent years, new data have been made public at higher resolutions, whether they are based on satellite, surveys or machine learning. In this work we want to study the impact of using updated datasets of land use and soil textures in the WRF model (v4.3) with the Noah-MP surface parameterization, which operationally runs at Meteorological Service of Catalonia (SMC). For the land use, we combine two sources, the Europe CORINE land cover (2018) at 100m resolution, and, with 1m resolution, one from the cartographic and geological institute of Catalonia (ICGC), an organization carrying out actions related to the awareness, survey and information about the soil and subsoil. For soil texture, we use SOILGRIDS, a system for global digital soil mapping that makes use of global soil  profile information and covariate data to model the spatial distribution  of soil properties, which includes some additional variables such as silt, density and gravel. These let us analyze the impact of three different pedotransfer functions: Saxton & Rawls (2006), Wösten(1999), Weynants (2009) that transform the variables given by the soil texture to the ones needed by the model. The results of the different initializations are verified against our surface station network for the spring 2023 to quantify their impact. Our results compared to the operational version show an improvement on wind and temperature, with a wider thermal range. Bibliography Jiménez-Esteve B, et al: “Land use and  topography influence in a complex terrain area: a high resolution  mesoscale modelling study over the Eastern Pyrenees using the WRF model.”  Atmos Res, 202, (2018):49–62  Pedruzzi R. et al: “Update of land use/land cover and soil texture for Brazil: Impact on WRF modeling results over São Paulo”, Atmospheric Environment, 268, (2022) Poggio, L., et al: “SoilGrids 2.0: producing soil information for the globe with quantified spatial uncertainty”, SOIL, 7,(2021), 217–240 Saxton K.E. et al: “Estimating generalized soil-water characteristics from texture”, Soil Sci. Soc. Am. J., 50 (1986), pp. 1031-1036 Weynants M. et al: “Revisiting Vereecken pedotransfer functions: introducing a closed-form hydraulic model”, Vadose Zone J., 8  (2009), pp. 86-95 Wösten J.H.M. et al: “Development and use of a database of hydraulic properties of European soils”, Geoderma, 90 (1999), pp. 169-185 