bluuebunny/crossref_metadata_2025 huggingface dataset:
EU Weather markets: a EU-28 perspective from 2010 to 2020 and beyond
Authors: Eccleston Andrew , Gutbrod Karl , Gruninger-Hermann Christian , Schulze Dennis
Published: June 2022

PRIMET has conducted a market research study on the weather services market in the EU-28 countries for the period of 2010-2020, including National and Private Weather services providers. The study covers annual revenue, employee numbers and segments of market activities. The study does not include the market for meteorological instruments, nor down-stream markets with integrators of meteorology information, such as insurances, agriculture and others.

The study identifies the market activity in each country by the 5 classes described below and makes some projections for the next decade.

a. monopolistic: private sector not allowed, only National Hydro-Meteorological Service (NHMS; state agency) allowed to provide weather services;

b. centralistic: private sector allowed, but NHMS is main provider of weather services and does not provide the necessary base data to private sector, so no, or only very few private companies exist (e.g. Romania);

c. oligopolistic: private sector allowed, NHMS provides the necessary base data to private sector, but influences rules and exerts strong commercial competition in the market place, so private companies are disadvantaged in the competition (e.g. France);

d. polipolistic: private sector allowed, NHMS provides all necessary base data to private sector, and is commercially active in some segments, without unfair competition in the market place (e.g. Germany);

e. free: private sector allowed, NHMS provides all the necessary base data to private sector as open data and is NOT commercially active (e.g. USA);

The research was undertaken independently by Prof. Dr. Christian Gruninger-Hermann of Baden-Wuerttemberg Cooperative State University Loerrach. Prof Gruninger-Hermann is a specialist in the fields of digital transformation and business models, Ecommerce, trade management and market research.

PRIMET is a pan European Trade Association for meteorological service providers operating in the private sector. It aims to promote a fair trading environment between the public and private sector in meteorology and its related disciplines. 
The ETH-Center for Climate Systems Modeling C2SM – enabling atmospheric science at the Zurich hub
Authors: Schnadt Poberaj Christina , Knutti Reto , Brunner Dominik , Croci-Maspoli Mischa , Gruber Nicolas , Plattner Gian-Kasper , Seneviratne Sonia , Stocker Benjamin
Published: June 2022

The Center for Climate Systems Modeling (C2SM) is one of ETH’s extradepartmental centres and a joint venture between ETH Zurich, MeteoSwiss, Empa, and WSL. The centre's mission is to provide a technical and scientific platform and a network for its partner institutions to support the development and application of complex models of the weather and climate system. It also supports the analysis and visualisation of climate data, to enable and facilitate collaborations within C2SM’s community and beyond, to exploit synergies among the partner institutions, and to engage in a dialogue with the general public and other stakeholders about climate-​relevant issues. C2SM also acts as the primary entry and interaction point for ETH, for national and international institutions, and for society at large on issues related to climate and climate change. C2SM currently focuses on four areas: 1) Working closely together with the Swiss National Supercomputer Centre (CSCS) and MeteoSwiss, as well as the international partners Deutscher Wetterdienst (DWD) and Max-Planck Institute for Meteorology (MPI), it develops and applies the next generation modelling paradigms in weather and climate. Specifically, in the six-year open ETH project EXCLAIM, C2SM together with its partners is developing an exascale computing and data platform for weather and climate modelling based on the weather forecast and climate model ICON that will be capable of simulating the regional to global ocean-sea-ice-atmosphere-land system on the kilometre scale globally. 2) C2SM works together with the community to maintain and further develop the atmospheric models and their extensions used in the community focusing on technical improvements and adaptations for high-performance computing. 3) Further, C2SM strongly engages in the development of the next generation Swiss climate scenarios in tight collaboration with the National Centre for Climate Services (NCCS) and MeteoSwiss. 4) C2SM also works together with experts in the areas of impact and risk modelling to foster the seamless integration of climate impact sciences into weather and climate models. Last, but no least, C2SM engages in the area of education and outreach by organising the Swiss Climate Summer School at two-yearly intervals and its annual outreach event ETH-Klimarunde, at which the public is informed about current topics of climate change. To support the research at C2SM and to provide these services, C2SM operates with a core budget of about 870 kCHF per year. This supports an executive director, 4.5 full time scientific programmers, and a small communication and event team that together form the C2SM core team.
A long-term climatology of boundary-layer height and stability at Hyytiälä in southern Finland.
Authors: Sinclair Victoria , Ritvanen Jenna , Urbancic Gabin , Batrak Yurii , Erner Irene , Moisseev Dmitri , Kurpaa Mona
Published: June 2022

The boundary-layer height and stability are two key parameters that control the exchange of energy between the surface and the atmosphere and strongly influence air quality and pollution dispersion. In this study, we investigate the boundary layer (BL) height and stability at the long-term measurement station of Hyytiälä, located in the Boreal forest of southern Finland at a latitude of 61.85N. A 41-year climatology of the annual and diurnal cycle of BL height was created based on ERA5 reanalysis data. The ability of ERA5 to correctly capture the BL height was determined by comparing ERA5 to BL heights derived from 847 radiosondes that were released from Hyytiälä as part of the 7.5 month “Biogenic Aerosols - Effects on Clouds and Climate” (BAECC) campaign in 2014. Four different methods to estimate the BL height were applied to the radiosondes. A 25-year climatology of surface-layer stability was created based on eddy covariance measurements and was used to identified under which conditions ERA5 can best capture the BL height and to better understand the annual and diurnal cycle of the BL height. The climatology results show that the shallowest (353~m) monthly median BL height occurs in February and the deepest (576~m) in June. The largest variability in BL height, and the largest diurnal range, was found in April and May. Notably, the shallowest BLs were found to occur at night in spring and summer which is also when very stable conditions were most likely to occur. Between November and February, there was no diurnal cycle in BL height due to the limited solar radiation at this time of year. Unstable conditions were rare during the cold season but so were very stable BLs. The absence of very stable conditions in winter is related to the stronger winds, and hence more shear-driven turbulence, compared to either spring of summer. Very shallow and stable BLs are also prevented from developing in autumn and winter due to the increased amount of cloud compared to spring and summer. Good agreement was found between the BL height in ERA5 and the BL height diagnosed from the radiosondes for almost all stability classes but ERA5 does overestimates the BL height in very stable conditions. In addition, ERA5 BL height differs most from the radiosondes at 18 UTC. These results suggest that ERA5 has adequate vertical resolution to correctly resolve the BL height in most conditions, that ERA5 struggles to correctly simulated stable BLs, and lastly that ERA5 does not resolve the evening transition correctly.    
A sensitivity study on high resolution ICON-LAM and comparison with COSMO over Southern Italy 
Authors: Bucchignani Edoardo , Cinquegrana Davide , Montesarchio Myriam , Zollo Alessandra Lucia
Published: June 2022

The ICON (ICOsahedral Nonhydrostatic) is a joint project between the Deutscher Wetterdienst (DWD) and the Max-Planck-Institute for Meteorology (MPI-M) for the development of a unified global numerical weather prediction system. In 2018, COSMO (COnsortium for Small-scale Modeling) started the migration from the COSMO-LM to the ICON-LAM (ICON Limited Area Model) as the operational model. The main aim of this work is the presentation of a sensitivity study performed over a domain located in southern Italy (including the northern part of the Campania region and the southern part of Lazio) aimed to provide a contribution to the definition of a model configuration suitable for accurate weather forecasts over this area. Following the work performed by the authors with COSMO on a similar domain, the week 19-25 November 2018 has been selected as test case, when a low-pressure system coming from Western Mediterranean determined intense storms and gusts.

A computational grid R2B11, characterized by a very high resolution (about 1.2 km), has been adopted. Initial and boundary conditions are provided by the ECMWF IFS model at a spatial resolution of about 8.5 km. The sensitivity was carried out starting from a model configuration optimized by the authors (in a joint effort with the CMCC Foundation, Italy) over the whole Italian area, employing a grid with different resolution (R2B10, about 2.5 km). The reference configuration assumes that the shallow convection parameterization is active whereas the parts treating deep and mid-level convection are switched off. Moreover, a single moment cloud microphysics scheme and a diagnostic Kohler cloud cover scheme are employed.

A first sensitivity was performed with respect to the domain size, considering a reference domain (11.38° – 15.38° E; 40.25° - 42.25° N) and two additional domains respectively larger (in both directions) than 50% and 100% with respect to the original one. Then, a sensitivity to the numerical parameters, which have been shown to play a significant role in determining model response, has been carried out, e.g tkhmin (minimal diffusion coefficient for heat), rlam_heat (factor for laminar resistance for heat) and v0snow (factor for vertical velocity of snow).

Model evaluation has been conducted against ground observation data provided by CIRA instrumentation and by the SCIA system developed by ISPRA (Italy). Moreover, a comparison with forecasts provided by the COSMO model at 0.009° (about 1 km resolution) forced by the same driving data has been performed, in order to highlight the differences between the performances of the two models.
The relationship between precipitation and extra-tropical cyclone intensity in different idealised climates
Authors: Sinclair Victoria , Catto Jennifer
Published: June 2022

Extra-tropical cyclones (ETCs) are the main cause of precipitation in the mid-latitudes. Some, but not all, ETCs can lead to heavy precipitation and flooding. Furthermore, not all extreme ETCs in terms of maximum vorticity – a commonly used measure of ETC intensity – lead to extreme precipitation. Therefore, this study quantifies the relationship between maximum vorticity and ETC related precipitation in the current and future climates, and determines how this relationship depends on the structure and characteristics of the ETC. These aims are addressed using three 10-year-long aqua-planet simulations performed with a state-of-the-art global model, OpenIFS. The simulations only differ in terms of the specified sea surface temperature (SST) distributions which are held fixed in time. The control simulation has the well-known “QObs” SST distribution, the uniform warming simulation has a 4K warming relative to the control simulation applied everywhere, and the polar amplification experiment has a 5K warming applied poleward of 45 degrees. The feature tracking software TRACK is applied to objectively identify and track all ETCs in each experiment and obtain the maximum 850-hPa vorticity of each ETC. k-means clustering is then applied to the precipitation field surrounding each ETC to group the ETCs into clusters with similar precipitation structures.

In all experiments, ETCs with stronger maximum vorticity were associated with more precipitation. This relationship was strongest in the uniform warming simulation and weakest in the control simulation. Considerable spread, particularly in the uniform warming experiment, was present in this correlation suggesting that not all ETCs have a strong correlation between maximum vorticity and precipitation. This is confirmed by the clustering results. The k-means clustering identifies 4 distinct types of ETCs which are present in all experiments. For two types of ETCs – those located at high latitudes with weak precipitation and those with the precipitation located mainly in the centre of the ETCs – there is only a very weak relationship between maximum vorticity and precipitation. The strongest relationship between ETC maximum vorticity and precipitation occurs for ETCs that have most precipitation associated with the warm front. These results will be presented along with dynamical interpretations.
Analysis of short-term precipitation extremes for design purposes in Hungary
Authors: Lakatos Monika , Izsák Beatrix , Szentes Olivér , Bihari Zita
Published: June 2022

The rainfall intensity for various return periods are commonly used for hydrological design. In this study, we focus on rare, short-term precipitation extremes and related return values which are relevant durations in the planning and operating demands of drainage and sewerage systems in Hungary.

Hungarian Meteorological Service together with the National Water Directorate (Municipal Water Management Department) with the professional assistance of the Hungarian Chamber of Engineers (Water Management and Water Construction Section) developed a user service for design purposes.  The user can download the return levels of the short-term rainfall intensity for the closest meteorological station to the location of the planned object specified with geographical coordinates.

Automatic stations replaced the ombrometer in many places in Hungary, particularly from the late 1990s. The change of the measurement practice do not allow simply merging the data recorded form the registering paper in the past and the recent 10 minutes measurements.   The most intense 5, 10, 20, 30, 60, 180 min sub-totals per rainfall events were recorded from the ombrometer registering paper before atomization, typically until 1993. By contrast, the 10 min precipitation sum from the AWSs are stored in the meteorological database of the Hungarian Meteorological Service from automatization. In order to join together the older and the AWS measurements it was necessary to develop a method to make this possible. Therefore, we downscaled the 10 min data in time. The sampling of the AWSs is one minute, although the 1-minute data are available only for some stations in the digital database. We applied a linear regression model to downscale the 10-minute data for 1 min. After this, we can derive the most intense sub-totals per events from the AWS data as if they have been measured with the ombrometers. Therefore, several station data series can be made longer, thus the confidence intervals of the return level estimates are narrowing, and the quality of the service is improving.
Spatial analysis of near-surface air humidity. Which variable?
Authors: Frei Christoph
Published: June 2022

Air humidity can be characterized by several variables (e.g. vapor pressure, dew point, relative humidity). Grid datasets of near-surface humidity are usually available for one of these only, say the daily mean relative humidity. If a different variable is needed in an application, say the vapor pressure deficit, the user is expected to derive it using familiar conversion formuli and a temperature dataset. A largely unnoticed problem of this procedure is that the conversion between variables is valid strictly for instantaneous values, but not for daily means considered in a daily grid dataset, because of non-linearity. In this study, the errors made with such conversion are examined using 10-minute observations at Swiss weather stations, applying the "inappropriate" conversions and comparing the results to the true daily means. The study is a preparatory step in the development of a gridded humidity dataset for Switzerland and its results point to more/less favorable decisions on the target variable.

The results show that the conversion introduces an error with a systematic component (bias) that is quantitatively significant. For example, calculating a daily mean vapor pressure deficit from daily mean relative humidity and temperature introduces a bias of about 10%. The bias is particularly large in summer and at the floor of major valleys, because of the large diurnal cycle of humidity and temperature. Our study explains the origin of the bias in terms of detail in the conversion formuli. An interesting result of our analysis is that conversions starting from dew-point temperature are less prone to error. It appears that dew-point temperature difference constitutes a relatively better choice of target variable for humidity grid datasets, at least with regard to precision of variable conversion. 
User-tailored climate predictions – the DWD climate predictions website
Authors: Mannig Birgit , Paxian Andreas , Tivig Miriam , Pankatz Klaus , Fröhlich Kristina , Hoff Amelie , Reinhardt Katja , Isensee Katharina , Wehring Sabrina , Buchholz Saskia , Pasternack Alexander , Lorenz Philip , Kreienkamp Frank , Früh Barbara
Published: June 2022

DWD publishes operational seasonal climate predictions since 2016. In the following years work towards a seamless climate predictions website commenced, with the aim to provide consistent climate predictions across all timescales, focused on the needs of national users.

Today, the DWD climate predictions website www.dwd.de/climatepredictions contains operational decadal and seasonal predictions. Next, we will add post-processed subseasonal prediction products, derived from the IFS forecasts provided by ECMWF, as a further step towards the seamless climate prediction approach.

The user-oriented graphical presentation of the climate predictions is identical over all timescales. It was co-designed with stakeholders from various sectors at user workshops on climate predictions and through surveys and individual user meetings to guarantee its comprehensibility and usability. This co-design always includes the aspect of how the available predictive power is clearly addressed and its limitations are presented in a way that is understandable to users.

As a result, the website offers different layers of information on a basic and an expert level. It includes maps, time series and tables of 1- and 5-year means (decadal) and 3-month means (seasonal) ensemble mean and probabilistic predictions of temperature and precipitation on a global scale and for Europe, Germany, and German regions. For the subseasonal scale, we will add corresponding figures for weekly means of temperature and precipitation.

The information on DWD’s climate predictions website is retrieved from post-processed model output of the German seasonal and decadal prediction systems based on MPI-ESM. A statistical recalibration is applied to improve the skill of decadal climate predictions. It performs a drift correction as well as a lead time dependent optimization of conditional bias and ensemble spread. To fit the needs of German climate data users of a high spatial resolution in Germany (~20 km) and for climate predictions for German cities (based on ~5 km simulations), the empirical-statistical downscaling EPISODES is applied. All predictions are displayed in combination with their skill.

We work on several extensions of the website: multi-year seasonal predictions (e.g. 5-year summer means), the prediction of extreme indices (e.g. drought indices) and El Nino Southern Oscillation predictions. In addition, a seamless time series combining observations, climate predictions and climate projections is in preparation.
Introducing Mobile Micrometeorological Carts (MMCs) for urban and non-urban micrometeorological measurements
Authors: Milošević Dragan , Savić Stevan , Šećerov Ivan , Dunjić Jelena
Published: June 2022

Most of the world’s population now lives in urban areas that have different urban climates and environmental characteristics with elevated temperatures, frequent heat stress, and air pollution due to urbanization and climate change. These processes affect the daily lives of citizens worldwide, however, detailed spatial and temporal meteorological and environmental data in cities are often lacking. In order to address this problem, the Novi Sad Urban Climate Research Team (NSUCRT) has developed a Mobile Micrometeorological Carts (MMCs) to enable detailed spatial and temporal measurements in urban and non-urban areas. MMCs consist of sensors that measure air temperature, relative humidity, wind speed and direction, globe temperature, global radiation, and six-directional short- and long-wave radiation. The measurement time resolution is two minutes. In addition, a desktop application was created for the transfer of data from MMCs to a computer. This type of detailed and precise equipment will enable researchers and practitioners to obtain micrometeorological data in diverse urban (and non-urban) areas, such as urban squares, streets, parks, river quays, forests, etc. Based on the obtained micrometeorological data, hot and cool spots in the city can be identified, which can be used for the development of climate-friendly planning and design guidelines tackling heat-health issues in cities. In addition, the obtained micrometeorological data can be used for the calculation of mean radiant temperature and outdoor thermal comfort indices, which are important for assessing the comfort and health of citizens in diverse urban environments. Finally, MMCs measurements can be applied for the validation of microclimate models, such as ENVI-met, PALM-4U, SOLWEIG, and RayMan.

Acknowledgment: The research was supported by a project (number 142-451-2557/2021-01) financed by the Autonomous Province of Vojvodina (regional government).
The potential insitu and downwind thermal conditions of a new coastal city built on reclaimed land in Lagos, Nigeria 
Authors: Morakinyo Tobi Eniolu , Simon Helge , Sinsel Tim , Bruse Michael
Published: June 2022

Due to the ongoing rapid urbanization, built-up landcover has geometrically increased in many global cities in recent years. Specifically, many coastal cities are almost using up their landed area, thus, land reclamation is increasingly becoming popular as a solution for further urban and economic development to cater for the growing population. However, such landcover changes could significantly impact the existing environmental condition and should be investigated.  One such case is the ongoing massive development of an expanse of reclaimed land on the Atlantic coast of Lagos, Nigeria. Thus, this study investigates the potential micro-climatic impact of the conversion of the large ocean surface to a built-up area, locally in the new development and downwind in the existing neighbourhood. To achieve this, we applied the ENVI-met micro-climate model in which a parametric study were conducted. Four scenarios i.e. the pre-reclamation - “reference” case, and three post-reclamation - “highly densified”, “grey design” and “grey-green design” scenarios were evaluated for their micro-climate and thermal comfort situations. Analyses involve the comparison between the pre-and post-reclamation scenarios, and inter-scenario comparison to reveal the influence of urban structure and design decisions on insitu and downwind thermal conditions. The result revealed both the insitu and downwind areas became warmer both at day and night-time due to significant (about 50%) landcover change from water to paved built-up surface. Although the imposed high-rise development on the reclaimed area has an impact on the ventilation flow pattern and magnitude, the relatively warmer air generated in the newly built area is still advected into the existing neighbourhood areas downwind.  However, depending on the urban structure/layout and design features imposed on the reclaimed area, the intensity of the consequent daytime and night-time warmth and thermal discomfort varies across the study domain. The warming intensity is stronger during daytime than nighttime and highest with the high densified/grey-design and otherwise with the green-grey design indicating the role of greening as a key climate-resilient strategy. Similarly, the green-grey design scenario improved the daytime thermal comfort condition significantly compared to the highly densified and grey design counterparts. However, at night-time, the downward longwave radiation from the trees made the environment warmer but this effect is significantly outweighed by the positive effect observed during the daytime. Finally, this study gave insights to developers, urban planners, architects, and decision-makers on the need to mitigate the potential environmental impacts of such large-scale land cover change and development.
Climate services landscape in Eastern Africa: A survey of how, when and by whom is climate information used
Authors: Mittal Neha , Bruno Soares Marta , Abdullahi Hassan Mohammed , Kipkogei Oliver , Baraibar Marta , Wachana Calistus
Published: June 2022

The landscape of climate services development and implementation is rapidly evolving and expanding across sectors and countries in the Eastern Africa region. However, very little is known about the how, when, if and by whom the climate information is used. To address this gap, we deployed an online regional survey across 11 countries in Eastern Africa with a wide range of information producers and users, and a total of 629 responses were received. This provided us a snapshot of the state of climate services in the region including an understanding on the use of existing services across countries and sectors provided by regional and national meteorological centres, the improvements required to increase their uptake and use as well as the new services needed. Our findings further revealed an appetite for sector and country specific tailored services alongside enhancement (skill, resolution, and visualisation), timely delivery products, and access to specific existing services. We also found that regional, national, and sub-national climate outlook forums can be further improved to provide not only timely seasonal climate information but to serve as an interface where sector experts and service users can benefit from iterative interactions. Our paper identifies opportunities for improving existing climate information products and services, as perceived by information users. Importantly, we identify how different channels of communication could be leveraged for the successful provision of existing climate services. This research, while novel in its scope, is important for informing future climate services research and implementation in this complex region of global importance.
The response of secondary chemical species to COVID-19 related emission distrubances
Authors: Brasseur Guy , Gaubert Benjamin , Bouarar Idir , Steinbrecht Wolfgang , Granier Claire , Doumbia Thierno
Published: June 2022

We use the global Community Earth System Model to investigate the response of secondary pollutants (ozone O3, secondary organic aerosols SOA) in response to modified emissions of primary pollutants during the COVID-19 pandemic. We use an estimate of the reduction in surface and aircraft emissions to derive the changes in the chemical composition of the atmosphere. We quantify the respective effects of the reductions in NOx and in VOC emissions, which, in most cases, affect oxidants in opposite ways. Using model simulations, we show that, relative to a situation in which the emission reductions are ignored, the ozone concentration increased only in a few NOx-saturated regions during the winter months of the pandemic when the titration of this molecule by NOx was reduced. In other regions, where ozone is NOx-controlled, the concentration of ozone decreased.  SOA concentrations decrease in response to the concurrent reduction in the NOx and VOC emissions. Zonally averaged ozone concentrations in the free troposphere during Northern Hemisphere spring and summer were 5 to 15% lower than 19-year climatological values, in good quantitative agreement with ozone observations. We examine the response in free tropospheric ozone at different latitudes and specifically in the southern hemisphere, the tropics, the northern hemisphere mid-latitudes and polar region. About one third of this anomaly is attributed to the drastic reduction in air traffic during the pandemic, another third to reductions in surface emissions, the remainder to 2020 meteorological conditions, including the exceptional springtime Arctic stratospheric ozone depletion. We compare calculated changes in the vertical ozone profiles with values derived from ozone sonde observations.
Portuguese wine denominations of origin under changing climates
Authors: Fonseca André , Santos João
Published: June 2022

Climate variability has a great impact on wine production and quality. To assess weather variability and climatic conditions, this research examines high-resolution extreme indexes of daily temperature and precipitation over 50 protected wine denominations of origin (DOs)/sub-regions in mainland Portugal. This study highlights the variations of present and future climate conditions between DO/sub-regions, for a better understanding of the nature of climate change across diverse regions of the country.

The analysis is based on a high-resolution dataset over mainland Portugal and for a baseline period (1981–2010). Climate change projections are also assessed for two scenarios (RCP4.5 and RCP8.5) and using a 5-member climate model ensemble retrieved from EURO-CORDEX climate projections data over the future periods of 2041–2070 and 2071–2100. A quantile mapping technique was used to bias correct the outputs from general circulation model (GCM) and regional climate model (RCM) combination.

The results highlight the spatial variability of Portuguese wine sub-regions for the present and future conditions. This study also shows that for future periods (regardless of the scenario) the wine sector in Portugal will likely see important climate changes across most regions. Increases in mean temperatures for each region accompanied by increasing severe dryness are projected in future climates mainly in south-eastern Portugal and along the upper Douro Valley (Douro Superior) in north-eastern Portugal. These DO/sub-regions are projected to become much drier than currently so irrigation or the introduction of new varieties are likely adaptation measures to maintain the viability and sustainability of regional viticulture in future decades.

Acknowledgments: Soil recover for a healthy food and quality of life (SoilRec4+Health). Projeto cofinanciado pelo Fundo Europeu de Desenvolvimento Regional (FEDER) através do Programa Operacional Regional do Norte (NORTE-01-0145-FEDER-000083).
Analysis of the Value Chain in the ‘7.20’ZhengZhou extreme rainfall event
Authors: Liang Xudong , Wang Yi , Zhang Qinghong
Published: June 2022

On 20th July 2021, an extreme rainfall event occurred at Zhengzhou city in China with maximum hourly rainfall of 201.9 mm and 24h accumulated rainfall of 624.1 mm at Zhengzhou weather station. This storm rainfall event caused huge damages of about 40.9 billion Yuan (RMB) property loss and 380 death. Using the Value Chain concept, the functions of observation, weather forecast, hazard forecast, impact forecast, warning and decision during this event were analyzed. The gaps between the “islands” in the Value Chain were emphasized. There are some limits in the observation system to monitor the event and few observations were passed into the next step of weather forecast. The gap between observation and weather forecast was obvious. The skills of global and regional numerical model forecasts were verified. The forecast skills for the extreme rainfall is low, and it is a challenge to forecast the location and amount of the extreme rainfall for the numerical model. How to improve the forecast skills from minutes to days for these extreme weather systems is still a big problem. The ability of hazard and impact forecast were low, and then lead to some delayed or mis decisions. It is indicated that cooperation between mult-discipline is required to improve the ability of hazard and impact forecast. Some high-level hazard warnings were issued during the event. It is helpful for the public and government making decisions and avoiding the damage, but it needs to be improved in some respect. This case is an example to demonstrate the importance of the idea of value chain in hazard mitigation.
European heatwaves in present and future climate simulations: A Lagrangian analysis
Authors: Schielicke Lisa , Allner Theresa , Pfahl Stephan
Published: June 2022

Heatwaves are prolonged periods of anomolously high temperatures. Also in combination with droughts, heatwaves can have devastating impacts on the environment, society and economy.  Dynamically, heatwaves are linked to large-scale, quasi-stationary atmospheric blocking patterns. Heatwaves have become more intense and more numerous over most land areas in the recent history. Due to the expected rise in global mean temperature, it is expected that this trend will continue. This general intensification in line with mean temperature may be modified by changes also in the underlying dynamical processes.

In order to study such potential changes in heatwave dynamics, we compare Lagrangian backward trajectories of air streams associated with historic (1991-2000) and future (2091-2100) heatwaves in six European regions. The heatwaves are identified based on a large ensemble of CESM climate simulations with  the help of the percentile-based Heat Wave Magnitude Index daily.

Compared to climatological values, air streams associated with heatwaves show a larger temperature increase along their trajectory, which is connected to stronger descent and stronger diabatic heating when the air parcels enter the boundary layer. For future heatwaves, the model projects a north-/northeastward shift of the origin of the air masses three days prior to the heat event in most study regions. Furthermore, we find larger diabatic temperature increases along the parcel trajectories in the future. This increasing importance of diabatic heating is more pronounced for heatwaves over continental regions. Boundary-layer diabatic temperature changes are driven by sensible heat fluxes, which are stronger over dry soils, associated with an increase of the Bowen ratio. The amplified diabatic heating associated with future heatwaves may thus be explained by an expected drying of the land surface.
Changes of social contacts due to the Covid-19 pandemic and the dependence on weather parameters
Authors: Schielicke Lisa , Bohmann May , Ertz Philipp
Published: June 2022

The Covid-Pandemic determines social life since the beginning of 2020. Several lockdowns forced people to reduce their social contacts, especially private contacts during their spare time. For fear of infection, some people even reduced their contacts over the whole time of the pandemic. The global virus pandemic is characterised by seasonal waves with periodically increasing and decreasing incidence. This periodic variability depends on many factors. Of central relevance are all kinds of social meetings and gatherings.  Covid-19 is an airborne disease and, hence, indoor meetings and activities without masks pose a significant higher risk of infection than outdoor meetings. The decision to meet indoors or outdoors depends largely on the waether -- amongst other parameters such as the kind of activity (sport, picnic, cooking, gaming, singing) or the composition and background of the  group (band, sports group, study group, students, parents with kids). The type of outdoor activity is strongly dependent on the weather.

In a two-way approach of surveys and data analysis, we want to find out how weather parameters such as temperature, wind, precipitation, cloudiness, etc. influence the decision to meet indoors or outdoors. On the one hand, surveys and interviews of students give insight into the special situation oft he social life of students during the pandemic. On the other hand, DWD weather observations of several German cities, contact data and infections numbers are statistically analysed in order to detect possible relationships between the parameters. In this work, we will present first results of this recently started project.
Tropospheric pathways of the late-winter ENSO teleconnection to Europe
Authors: Mezzina Bianca , Garcia-Serrano Javier , Ambrizzi Tercio , Matei Daniela , Manzini Elisa , Bladé Ileana
Published: June 2022

The late-winter signal associated with the El Niño-Southern Oscillation (ENSO) over the European continent is unsettled. Two main anomalous patterns of sea-level pressure (SLP) can be identified: a “wave-like” pattern with two opposite-signed anomalies over Europe, and a pattern showing a single anomaly (“semi-isolated”). In this work, potential paths of the tropospheric ENSO teleconnection to Europe and their role in favoring a more wave-like or semi-isolated pattern are explored. Outputs from historical runs (1850-2005, 3 members) of two versions of the MPI-ESM coupled model, which simulate these two types of patterns, are examined. The two versions of MPI-ESM have same horizontal resolution in the atmosphere (T63/1.9º), same top (0.01 hPa), but different vertical resolution: 47 levels in the low-resolution (LR) version and 95 in the mixed-resolution (MR) one. Results from the models are compared with observational ones using the NOAA-20CR reanalysis. A novel ray-tracing approach that accounts for zonal asymmetries in the background flow is used to test potential propagation paths in these simulations and in observations; three source regions are considered: the tropical Pacific, the North America/North Atlantic, and the tropical Atlantic. The semi-isolated pattern is suggested to be related to the well-known Rossby wave train emanating from the tropical Pacific, either via a split over northern North America or via reflection due to inhomogeneities in the background flow. The wave-like pattern, in turn, appears to be related to a secondary wave train emerging from the tropical Atlantic. The competition between these two pathways contributes to determining the actual surface response.
LIAISE campaign: Measuring and Modelling Evapotranspiration over Irrigated Terrain in a Semi-Arid Environment
Authors: Hartogensis Oscar , Boone Aaron , Mangan Mary-Rose , Bellvert Joaquim , Best Martin , Brooke Jennifer , Canut-Rocafot Guylaine , Cuxart Joan , Le Moigne Patrick , Miro Josep Ramon , Polcher Jan , Price Jeremy , Quintana Segui Pere
Published: June 2022

The overall objective of the Land surface Interactions with the Atmosphere over the Iberian Semi-arid Environment (LIAISE) project is to improve the understanding of land-atmosphere and hydrology interactions in a semi-arid region characterized by strong surface heterogeneity owing to contrasts between the natural landscape and intensive, irrigated agriculture. It is known that irrigation can potentially impact the local atmospheric boundary layer (ABL) characteristics, thereby modifying near surface atmospheric conditions within and downwind of irrigated areas (e.g., Lawston et al., 2020) and potentially the recycling of precipitation. The understanding of the impact of anthropization and its representation in models have been inhibited due to a lack of consistent and extensive observations. In recent years, land surface and atmospheric observation capabilities have advanced while irrigated surfaces have been increasing, leading to a renewed need for dedicated field campaigns over contrasting (climate) regions.

We present a summary of the LIAISE field campaign intensive phase between July 15–29 2021, which took place over the Catalan counties of Urgell and Pla d'Urgell within the Ebro basin in north-eastern Spain. LIAISE is located in a semi-arid hot, dry Mediterranean climate, with a very sharp delineation between a vast, nearly continuous intensively-irrigated region and the generally much more dry rain-fed zone to the east of the study domain. Intensive, spatially distributed surface-based and airborne measurements of the atmospheric boundary layer were made, along with intensive eco-physiological observations and remotely-sensed high spatial resolution mesoscale measures of surface variables from aircraft and unmanned aerial vehicles (UAVs). Two energy budget sites were extended with a network of soil moisture sensors since they were used to evaluate remote sensing data from aircraft. More than 30 institutions took part in the campaign covering a wide range of expertise and spatiotemporal scales in the methods involved, be it through modelling or measurements.

In this contribution we will elaborate on the spatial and temporal scales involved in the processes of evapotranspiration. We will make a strong case for integrated approaches combining observation and modelling techniques to further develop our understanding of evapotranspiration. This will be illustrated with a case study using a mixed layer column model heavily guided and constrained by measurements. 
CroMonthlyGrids - monthly air temperature grids for climate monitoring and climate change detection
Authors: Perčec Tadić Melita , Pasarić Zoran , Guijarro Jose A.
Published: June 2022

The focus of this work is to create homogenised mean monthly air temperature series, produce monthly temperature grids and derive climate monitoring products to assess the state of air temperature and the observed temperature change in Croatia. Having that in mind, monthly mean temperatures from 122 Croatian stations are homogenised and high resolution monthly gridded data are developed for the 1981-2018 period. The hierarchical clustering is introduced to define climate regions in Croatia needed for homogenisation. The breaks of homogeneity are detected by the standard normal homogeneity test. Further on, the regression kriging is applied to produce 1 km x 1 km monthly grids for each month in the analysed period. The quality of the interpolation was assessed by leave-one-out cross-validation and the root mean square error of 0.7°C. The quality of spatial interpolation is estimated with normalised error maps. Climate normals and trends are derived from homogenised station data and monthly grids. After 2000, average annual anomalies from the 30-years climate normal 1981-2010 were positive and up to 1.4°C warmer than the average, and just occasionally negative. The significant strong warming is observed and mapped over the entire Croatian territory in April, June, July, August and November, being stronger inland than on the coast. Annual trends were significant and in the range from 0.3°C/decade to 0.7°C/decade. That suggests that our region could face consequences such as devastating heatwaves, water shortages, loss of biodiversity and risks to food production, especially as being part of the Mediterranean where it seems that the observed trends are 2-2.5 times stronger than the global mean. We can hope that some of the presented climate monitoring products can help in assessing the vulnerability and the risk from climate change and help with the mitigation of the potentially affected sectors like forestry, agronomy, tourism, water management, energy production or consumption, health or others.
Turbulent slope winds in complex terrain: from heat and moisture transport to the sampling of single plumes
Authors: Weinkaemmerer Jan , Göbel Matthias , Bastak Duran Ivan , Serafin Stefano , Schmidli Jürg
Published: June 2022

Local thermal circulations developing over heated valley slopes strongly influence the convective boundary layer (CBL) over mountainous terrain. For this study, large-eddy simulations are carried out both over idealized valleys and semi-idealized complex terrain. The flow is decomposed into a turbulent part, a local mean circulation capturing the slope winds, and a large-scale (upper-level) wind. This allows a detailed budget analysis for heat and moisture. The temperature distribution is horizontally fairly uniform inside each valley due to the homogenizing effect of the thermally-induced circulations. In contrast to that, the slope winds contribute strongly to the transport of moisture up to the ridges. The entrainment of dry air by the recirculation leads to a horizontally non-uniform moisture distribution. Consequently, a large-scale, upper-level wind hardly affects the horizontally homogeneous temperature distribution while it can considerably reduce the vertical moisture transport: a horizontal wind mixes the moisture from the slope-wind layer into the dryer regions of each valley. Single updrafts mark the small-scale end of coherent motions in the CBL over complex terrain. A conditional sampling method is applied in order to identify the thermal plumes using a passive tracer. In the mixed layer, the plumes are moving upslope with the slope wind. In order to quantify the contribution of the plumes to the vertical transport of heat and moisture, the joint probability density functions of the turbulent fluxes are calculated and decomposed into a local and a coherent part. From this perspective, the turbulence statistics is analyzed at different heights in the CBL and compared to the statistics over flat terrain. In general, the plumes turn out to dominate the vertical fluxes in the valleys and in the lower part of the boundary layer. Especially at ridge height, where the updrafts are few but almost stationary, the statistics are fairly different.
Towards transient aerosols in ICON-CLM - Impact of different aerosol climatologies
Authors: Petrik Ronny
Published: June 2022

Within the framework of the project NUKLEUS (Actionable local climate information for Germany) first long-term simulations with COSMO 6.0 and ICON-CLM based on the latest release ICON NWP 2.6.4 have been performed. These simulations were driven by ERA5 reanalysis data, which were downscaled to the EUR-11 EURO-CORDEX grid having a resolution of about 12 km. To capture the whole EURO-CORDEX domain with the ICON-CLM, a R13B05 icosahedral grid with a shifted North pole was chosen. The simulation period covers more than two decades starting from 1981.

In our presentation we aim to study the basic behaviour of transient ICON-CLM hindcasts in “local area mode” configuration. First evaluation results showed ‘questionable’ results for specific periods. After detailed analysis for the reasons of the model deficits, sensitivity experiments were carried out with purely lateral nudging and additional upper boundary nudging for ICON but for COSMO as well. It will be shown that the integration of both models leads to comparable solutions and a comparable level of sensitivity to weaker atmospheric forcing.

Furthermore to the search for an optimal configuration / Keeping in mind a first ‘optimal’ configuration, the performance of ICON-CLM and COSMO-CLM is investigated. In addition to a standard evaluation of relevant climatological parameters, the characteristics of radiative fluxes, clouds and the water budgets are analyzed. Systematic differences as well as similarities between both model simulations will be emphasized during this presentation. We will in particular focus on the impact of different aerosol climatologies on the model's quality.