bluuebunny/crossref_metadata_2025 huggingface dataset:
A new LES-based system for short-range forecasting of near-surface wind gusts at airports
Authors: Knoop Helge , Maronga Björn
Published: June 2021

Severe wind gusts associated with strong-wind events like winter storms are regarded as the biggest thread to aviation safety during takeoff and landing. In order to get forecasts for gust hazards during strong-wind conditions, airport operators currently still rely on empirical wind gust estimation (WGE) methods that are driven solely by mesoscale and regional numerical weather prediction (NWP) model data. These models currently have grid resolutions on the order of 1 kilometer and do not adequately resolve local topography and vegetation. This is especially problematic, as these local obstacles are a primary source of near surface turbulence. This turbulence is responsible for wind gusts, but it can also no be resolved by mesoscale and regional NWP models and has to be parameterized entirely. Consequently the empirical WGE methods completely neglect the real local obstacles around a specific airport, which leads to significant uncertainties in the wind gust hazard forecasts for airspace that is downwind from those obstacles. In case this airspace is used for takeoff and landing, airport operators have no access to reliable wind gust hazard forecasts. A more adequate and physical approach to resolving local obstacles and the turbulence they induce, is high-resolution large-eddy simulation (LES). We use the high-res LES model PALM to investigate, how wind gusts induced by local obstacles impact airspace used for takeoff and landing at the airport in Frankfurt, Germany. Moreover, we evaluate how accurate these LES results are compared to high-res wind measurements from multiple sites throughout the airport and we quantify the forecast quality of the LES approach vs. the traditional empirical WGE approach. Finally, we outline a path to apply PALM as a magnifying glass nested into mesoscale models with the goal of providing a new and improved forecasting system for gust hazards at airports. This new forecasting system can be used to improve existing empirical WGE approaches and it can be applied in an operational setting to produce new gust forecast products.
Evaluation of the relationship between meteorological and hydrological droughts in the southern Iberian Peninsula
Authors: Romero-Jiménez Emilio , García-Valdecasas Ojeda Matilde , Yeste Patricio , Rosa-Cánovas Juan José , Gámiz-Fortis Sonia Raquel , Castro-Díez Yolanda , Esteban-Parra María Jesús
Published: June 2021

Society is facing a challenge due to climate change. Particularly, there are several areas where droughts will impact economic activities and landscapes, and decisions must be made in order to alleviate these effects. River flow regulation plays a major role in this regard, since it reduces the existing correlation between meteorological and hydrological droughts.
The aim of this work is to investigate the response of hydrological drought to meteorological drought under the influence of reservoir. To this effect, the Guadalquivir River Basin, in the southern Iberian Peninsula, has been studied. The aridity of this basin is expected to increase in the future, with longer and more severe meteorological droughts. Moreover, the Guadalquivir presents a strong regulation along its course. Therefore, streamflow and precipitation data have been analysed. With these data, meteorological and hydrological drought indices, such as the Standardized Precipitation Index (SPI), the Standardized Precipitation-Evapotranspiration Index (SPEI), and the Standardized Streamflow Index (SSI), have been calculated, focusing on how they correlate based on time scale and spatial distribution. The meteorological drought indices have been calculated in varying time scales, showing that the hydrological response is different depending on characteristics such as orography and river section. The correlation between the indices is generally strong in the study area, but the results show that its importance decreases as the streamflow becomes more regulated.
The results of this study could be added to the current tools for decision making in the economic fields that are most affected by droughts. Since droughts are a major effect of climate change in the area, this study could also act as a first step for the study of future droughts through climate and hydrological models.
Keywords: Drought indices, river regulation, hydrological response.
ACKNOWLEDGEMENTS: This work was funded by the FEDER / Junta de Andalucía - Ministry of Economy and Knowledge / Project [B-RNM-336-UGR18], and by the Spanish Ministry of Economy, Industry and Competitiveness, with additional support from the European Community Funds (FEDER) [CGL2017-89836-R].
A new pan-European dataset for gridded daily average wind speed based on in-situ observations
Authors: de Baar Jouke , van der Schrier Gerard , Garcia-Marti Irene , van den Besselaar Else
Published: June 2021

Objective

The purpose of the European Copernicus Climate Change Service (C3S) is to support society by providing information about the past, present and future climate. For the service related to in-situ observations, one of the objectives is to provide high-resolution (0.1x0.1 and 0.25x0.25 degrees) gridded wind speed fields. The gridded wind fields are based on ECA&D daily average station observations for the period 1970-2020.

Research question 

We address the following research questions: [1] How efficiently can we provide the gridded wind fields as a statistically reliable ensemble, in order to represent the uncertainty of the gridding? [2] How efficiently can we exploit high-resolution geographical auxiliary variables (e.g. digital elevation model, terrain roughness) to augment the station data from a sparse network, in order to provide gridded wind fields with high-resolution local features?

Approach

In our analysis, we apply greedy forward selection linear regression (FSLR) to include the high-resolution effects of the auxiliary variables on monthly-mean data. These data provide a ‘background’ for the daily estimates. We apply cross-validation to avoid FSLR over-fitting and use full-cycle bootstrapping to create FSLR ensemble members. Then, we apply Gaussian process regression (GPR) to regress the daily anomalies. We consider the effect of the spatial distribution of station locations on the GPR gridding uncertainty.

The goal of this work is to produce several decades of daily gridded wind fields, hence, computational efficiency is of utmost importance. We alleviate the computational cost of the FSLR and GPR analyses by incorporating greedy algorithms and sparse matrix algebra in the analyses.

Novelty   

The gridded wind fields are calculated as a statistical ensemble of realizations. In the present analysis, the ensemble spread is based on uncertainties arising from the auxiliary variables as well as from the spatial distribution of stations.

Cross-validation is used to tune the GPR hyper parameters. Where conventional GPR hyperparameter tuning aims at an optimal prediction of the gridded mean, instead, we tune the GPR hyperparameters for optimal prediction of the gridded ensemble spread.

Building on our experience with providing similar gridded climate data sets, this set of gridded wind fields is a novel addition to the E-OBS climate data sets.
EUMETNET SRNWPEPS-EPS project and convection-permitting LAM-EPS database
Authors: Callado-Pallarès Alfons
Published: June 2021

SRNWP-EPS module/project into EUMETNET NWP Cooperation Programme has as main goals facilitating and coordinating the cooperation on developing reliable mesoscale convection-permitting ensemble systems (LAM-EPS) in Europe, and, at the same time, grouping efforts developing tools which can be smoothly applied to any LAM-EPS. This is motivated by the fact that the development of LAM-EPS capabilities in Europe is crucial for forecasting a range of weather phenomena and in particular for improving HIW (High Impact Weather) prediction. Due   to the latter, the current SRNWP-EPS 2019-2023 phase is focused on extreme events.

The project results as a survey on products for high-impact weather forecasting and the R2O (Research to Operations) LAM-EPS applications will be presented. The three main R2O forecasting tools developed as project requirements are: calibration of daily and  12 hours extremes for variables such as 10 metres maximum wind gusts, maximum accumulated precipitation, maximum and minimum2m temperatures; the forecasting post-processing LAM-EPS products devoted to HIW forecasting and focused on aeronautics such as icing, thunderstorms’ diagnostic and classification, clear-air turbulence and fog; and tools to apply in an affordable way an Extreme Forecast Index (EFI) and Shift of Tales Index (SOT) on LAM-EPSs.

Moreover, an off-line database of European convection-permitting LAM-EPS ensembles has been established at ECMWF, which archives convection related parameters close to the surface. The aim of LAM-EPS database is to foster coordinate research and collaborations around LAM-EPSs in order to improve HIW events bringing together all European LAM-NWP consortia (ALADIN, HIRLAM, COSMO, LACE, MetOffice partners, etc.). At the time of writing, nine participants are currently archiving since 1st of June of 2020: MOGREPS-UK (MetOffice), MEPS (MetCoOp), γSREPS (AEMET), IT-EPS (ItAF-REMET), IREPS (Met Éireann), COMEPS (DMI), MF-AromeEps (MétéoFrance), RMI-EPS (RMI) and ICON-D2-EPS (DWD). The SRNWP-EPS convection-permitting LAM-EPS database is currently being used by project research sub-groups, for example to check multi-ensemble performance or comparing two LAM-EPSs in their common overlapping area.
Spatial resolution of probabilistic forecasts and its impact on risk perception and precautionary action
Authors: Gubernath John , Fleischhut Nadine
Published: June 2021

In the context of probabilistic forecasting, low probabilities are known to be often underestimated by forecast users. This underestimation of low probabilities may have severe consequences, if people fail to take adequate precautions to protect against high-impact events like storms.
One solution is to communicate higher probabilities by lowering the forecasts’ spatial resolution: the lower the resolution, the higher the probability that the event will occur within the area. At the same time, a lower resolution entails more uncertainty about where exactly the event could occur. Thus, whereas a lower forecast resolution may heighten forecast users’ risk perception through larger probabilities, an increase in spatial uncertainty could reverse this effect. 

In an online experiment, we investigate the effects of forecast resolution and spatial uncertainty on risk perception and precautionary decisions (N = 149). For 12 probabilistic thunderstorm forecasts, participants (i) entered how likely they believed their location would be hit by a thunderstorm, and (ii) decided whether to host an outdoor event at that location at a risk of a high loss or cancel in advance at a smaller cost (blocks randomized).

We find that a lower forecast resolution significantly reduced how likely participants believed to be hit and how often they chose to protect against thunderstorms. At the same time, higher forecast probabilities increased participants’ risk perception and likelihood to take precautionary action. Furthermore, the interpretations of the forecast’s spatial reference assessed in multiple choice formats were only a rough proxy for experimentally observed perceptions of risk.
The results constitute a starting point for investigating the trade-off between forecast probability and spatial uncertainty. They also reiterate that the spatial resolution forecasters choose for their products directly influence forecast users’ risk perception and behavior.
Evolution of extreme summer precipitation patterns in the western Mediterranean basin
Authors: Benetó Vallés Pau , Khodayar Pardo Samira
Published: June 2021

The precipitation at the Mediterranean coast of the Iberian Peninsula is strongly seasonal and presents a non-uniform spatial distribution due to complex topography. Summer is generally dry and rainfall is mainly produced by orographically-induced convective precipitation (commonly known as summer storms) generated over the mountain ranges of the basin. Projections of future climate change indicate a generalized reduction of both mean precipitation and summer storms over eastern Spain. Summer storms play a key role in the local climate and the hydrological cycle since they are fundamental for the region water resources and ecosystems providing necessary precipitation during the driest season of the year.

In this study, an extensive analysis of precipitation spatio-temporal patterns during summer, with special focus on summer storms, is conducted over the Hydrographic Confederations of the Júcar (CHJ) and Segura (CHS) located in the southeastern part of the Iberian Peninsula. Specifically, the Spain02 precipitation dataset, covering the period 1951-2019 in a daily base with a 5-km horizontal resolution, is used to analyze extreme precipitation and dry days trends over the study area, as well as at a more local scale regarding the river basins that conform the CHJ and CHS. In addition, the last two decades are analyzed using a disaggregation of precipitation events regarding its origin and development: (A) Atlantic advection, (B) summer storms and (C) Mediterranean advection. Besides, high-resolution simulations (about 3km), performed with the COSMO mesoscale model, will provide further information with respect to the influence of summer storms on the local climate and the hydrological cycle.

Contrarily to the negative tendency in number of summer storms and precipitation amount observed during the period 1951-2019 for summer, preliminary results show an increase in the number of these particular events in both CHJ and CHS during the late summer (August and September) for the last two decades along with a slightly increasing precipitation trend. In our discussion we will describe in detail the observed changes in the precipitation field in combination with changes in other water cycle components, such as soil moisture, and evaporation and the potential implications for the affected regions.
The Africa weather enterprise : filling a large gap
Authors: Copping Tom
Published: June 2021

The study focuses on the role of the private sector in the development and delivery of hydromet and early warning services (EWS) in sub-Saharan Africa, within the current landscape of the Africa Regional Weather Enterprise (ARWE).

The study was sponsored by the World Bank and conducted through interviews with 28 National Hydro­Meteorological Services (NMHS) and 87 participating companies who either work in or have interest in the region’s hydromet market, varying in size from single-person entities to large multinationals. Less than 4% of companies have their headquarters (and solely operate) in Africa. 157 projects were identified from the 65 most active donors financing hydromet projects in sub-Saharan Africa, and classified by sector and complexity, from niche to “full-chain” solutions.

The study analyses which and how private sector actors operate within the framework of national, regional and international hydromet projects, in which countries, which products and services they provide and in which end-user categories, from research and development, to innovation and capacity building initiatives.

The study further analyses the success rates of international companies winning tenders in sub-Saharan Africa , and the patterns leading to success.

The report concludes by drawing on lessons from the positive dynamics and gaps in partnerships and engagements between public and private actors. The results of the study create the need for sixteen recommendations to further improve the ARWE, with a key emphasis on PPE, to successfully complete African hydromet programs, and in turn satisfy end-user needs, to protect lives, property, and to support their national economies for the prosperity of all.
Wintertime temperature extremes in the high Arctic: drivers, statistics and implications for the mid-latitudes
Authors: Messori Gabriele , Woods Cian , Wada Ryoto , Caballero Rodrigo
Published: June 2021

Temperature extremes in the high Arctic have made the headlines in recent years, with wintertime warm spells approaching 0 °C at the North Pole. In the first part of this presentation, I will outline some salient large-scale and synoptic atmospheric drivers of wintertime warm and cold spells in the high Arctic. The warm spells are systematically associated with a large-scale circulation pattern that creates a natural pathway for extreme moisture intrusions from the Atlantic sector into the Arctic. Anomalies in the distribution of synoptic cyclones then favour a deep penetration of these intrusions across the Arctic basin. The large-scale circulation pattern associated with the warm spells further favours the advection of cold air across central-northern Eurasia. On the contrary, cold Arctic extremes are associated with a persistent low-pressure system over the pole. This effectively isolates the high latitudes from mid-latitude air masses, favouring an intense radiative cooling of the polar region. In the second part of the presentation, I will discuss return times of the wintertime warm spells, using a novel approach grounded in extreme value theory. This approach explicitly takes into account the spatial structure of the moisture intrusions driving the temperature extremes, and I will try to convince you that it provides a more realistic set of estimates than conventional return-time algorithms.
Weather forecast on social media platforms
Authors: Üveges Zoltán
Published: June 2021

At the Hungarian Meteorological Service, three years ago we established a media meteorology group of forecasters with my lead. Our main goal is presenting the latest weather forecasts, interpreting weather related news and informative articles on various social media platforms like Facebook, Instagram and YouTube. One of our most popular types of forecasts – which was the topic of the award - is the daily weather forecast short video. What makes it quite different from and more authentic than a usual TV forecast is that our team members are forecasters, content editors and weather presenters in one person. Besides being the head of the group, I am also responsible for creating and designing the visual content.

We believe that forecasts have to be presented in the most simple language. However, weather related questions rarely can be answered with a simple yes or no. That is when probability forecasts come in handy. Presenting plume diagrams, probability maps help us smoothen the expectations of the public. With probabilities, we can speak of the medium range outlook on state of the art scientific basis, we don’t have to tell one single value for the 6th or 7th day maximum temperature and later receive the negative comments. I think it is important not to feel shame to say „we don’t know exactly” the details of the expected weather. Nowadays, communication of uncertainties is one of the main objectives of forecasters, and this sometimes requires that ungrateful task, too.

In our experience weather forecasts appearing indirectly in the media or press fail to contain uncertainties, information is usually transformed and mostly the worst case scenario is the only one which is presented. In order to avoid it, we try to reach the public directly via social media platforms and try to produce content with eye-catching headlines that is ready to use for the media.

The European Meteorological Society Media Weather Forecast Award gave us good feedback that we are on the right way of presenting weather, communicating probabilities in a scientific but understandable form for the public.
The interaction between a low-level jet and the boundary layer in complex topography
Authors: Trini Castelli Silvia , Haikin Nitsa
Published: June 2021

A study investigating the effect of a low-level jet (LLJ) event on the boundary-layer (BL) turbulent structure is presented.  During a radiosounding campaign aimed at investigating the atmospheric circulation in the area of Mount Carmel and Haifa Bay in Israel (35E - 33N), characterized by a complex terrain and a winding and jagged coastline, a couple of consecutive profiles showed a significant LLJ in the morning of January 7, 2010. Since there are no previous measurements or information about frequency or characteristics of the LLJ in this region, the scarcity of observed data does not allow addressing the nature and features of the LLJ. Therefore, its characteristics and development, and also its impact on tracer dispersion, have been explored through model simulations, using RAMS atmospheric model. RAMS was configured with four nested grids with resolution from 32 km to 500 m. A high vertical resolution in the inner grid was achieved with 15 levels below 400 m, using a vertical nesting with a rather novel approach not frequently adopted. RAMS simulated variables were verified against the available observations, providing a reliable reproduction of the LLJ pattern. An elevated inversion characterized the temperature profiles and the LLJ was located at the bottom of such inversion. An analysis of the turbulence kinetic energy (TKE) versus a jet-Richardson number showed that a strongly turbulent weakly-Stable-BL was characterizing the LLJ episode. At the hours of the peak of the LLJ event, 0700 and 0800 UTC (0900 and 1000 LT), two separate maxima, generated below and above the layer affected by the LLJ, appeared in the TKE vertical profiles due to the strong wind shear. Being a morning LLJ, when buoyancy-driven vertical motions started to develop they acted sustaining the turbulence below the LLJ, then decaying at higher elevation opposed also by the strong wind speed at the LLJ level. These and other results are presented and discussed, as a contribution to the understanding of LLJ dynamics and its impact on the boundary layer in complex topography.
GNSS-based Precipitable Water Vapor for the Global Climate Observing System
Authors: Dick Galina , Jones Jonathan , Wang Junhong , Rannat Kalev , Wickert Jens , Zus Florian , Männel Benjamin , Balidakis Kyriakos , Wilgan Karina
Published: June 2021

The Global Climate Observing System (GCOS), supported by a number of international partners and the World Meteorological Organization (WMO), is establishing a reference climate observation network, the GCOS Reference Upper Air Network (GRUAN). Currently, this network comprises 30 reference sites worldwide, designed to detect long-term trends of key climate variables such as temperature and humidity in the upper atmosphere, thus providing a cornerstone to more reliable monitoring of signals of global and regional climate change. GRUAN observations are required to be of reference quality, with known biases removed and with an associated uncertainty value, based on thorough characterization of all sources of measurement.

In support of these goals, GNSS precipitable water (GNSS-PW) measurement has been included as a priority one measurement of the essential climate variable water vapor. In addition, a minimum of twice daily measurements (ideally hourly measurement) of PW are required as entrance to the GRUAN program. GNSS-PW is the primary means to accomplish this entrance requirement. The GNSS-PW program produces a nearly continuous reference measurement of PW and is therefore a substantial part of GRUAN.

GFZ contributes to GRUAN with its expertise in processing of ground-based GNSS network data to generate precise PW products. Since 2013, GFZ hosts a GRUAN central processing facility for the GNSS-PW. GFZ is responsible for the installation of GNSS hardware, data transfer, processing and archiving, derivation of GNSS PW products according to GRUAN requirements including PW uncertainty estimation, as well as for quality check and archiving of the GNSS-PW products. Currently half of the GRUAN sites are equipped with GNSS receivers. At the beginning of this year the data processing of GNSS-PW and its associated documentation has been GRUAN certified. GNSS-PW products including uncertainty estimation and results of selected validation studies are presented.

 
Impacts of the Westerlies on Planetary Boundary Layer Growth Over a Valley on the North Side of the Central Himalayas
Authors: Chen Xuelong
Published: June 2021

The spatial-temporal structure of the Planetary Boundary Layer (PBL) over mountainous areas can be strongly modified by topography. The PBL over the mountainous terrain of the Tibetan Plateau (TP) is more complex than that observed over its flat areas. To date, there have been no detailed analyses which have taken into account the topography effects exerted on PBL growth over the Tibetan Plateau (TP). A clear understanding of the processes involved in the PBL growth and depth over the TP’s mountainous areas is therefore long overdue.The PBL in the Himalayan region of the Tibetan Plateau (TP) is important to the study of interaction between the area’s topography and synoptic circulation.

This study used radiosonde, in-situ measurements, ERA5 reanalysis dataset and numerical model to investigate the vertical structure of the PBL and the land surface energy balance in the Rongbuk Valley on the north of the central Himalaya, and their association with the Westerlies, which control the climate of the Himalaya in winters. Two sunny November days in 2014 with different synoptic conditions in terms of large-scale wind direction and speed were selected to investigate the ways in which large-scale synoptic forcing affected the vertical structure of the PBL, atmospheric stability, surface wind field, and land surface energy fluxes. The results revealed that the valley winds and PBL growth were strongly influenced by the variations of the westerlies. When the synoptic wind direction at the height of the mountain ridges was parallel to the axis of the valley, the downward transmission of the westerlies to the valley floor (DTWTV) was strong and cause high near-surface wind speeds and sensible heat flux value, then produced an extremely deep PBL (9 km above sea level) in the early afternoon of November 23. When the synoptic wind direction at the ridge height intersected the axis of the valley and was weak, the DTWTV was weak, and the PBL became relatively low on November 28. These results demonstrate that the interaction between the topography and synoptic circulation plays a critical role in PBL growth.
Potential influence of meteorological conditions on early COVID-19 transmission dynamics in 409 cities across 26 countries
Authors: Lowe Rachel , Armstrong Ben , Abbott Sam , Meakin Sophie , O'Reilly Kathleen , von Borries Rosa , Schneider Rochelle , Royé Dominic , Hashizume Masahiro , Pascal Mathilde , Tobias Aurelio , Vicedo-Cabrera Ana , Gasparrini Antonio , Sera Francesco ,   MCC Network & CMMID COVID-19 working group
Published: June 2021

More than a year since its emergence, there is conflicting evidence on the potential influence of weather conditions on COVID-19 transmission dynamics. Respiratory viral infections often show seasonality, with influenza and other coronaviruses peaking in winter, yet the underlying mechanisms are poorly understood. As SARS-CoV-2 is a new virus to humans, it is difficult to ascertain if seasonal climate variations might have enhanced or reduced transmission in the first pandemic wave given the high proportion of susceptible people and the potential confounding role of different types of non-pharmaceutical interventions adopted at different times after the onset of local outbreaks. We used a two-stage ecological modelling approach to estimate weather-dependent signatures in COVID-19 transmission in the early phase of the pandemic, using a dataset of 3 million COVID-19 cases reported until 31 May 2020, spanning 409 locations in 26 countries. We calculated the effective reproduction number (Re) over a city-specific early-phase time-window of 10-20 days, for which local transmission had been established but before non-pharmaceutical interventions had intensified, as measured by the OxCGRT Government Response Index. We calculated mean levels of meteorological factors, including temperature and humidity observed in the same time window used to calculate Re. Using a multilevel meta-regression approach, we modelled nonlinear effects of meteorological factors, while accounting for government interventions and socio-demographic factors. A weak non-monotonic association between temperature and Re was identified, with a decrease of 0.087 (95% CI: 0.025; 0.148) for an increase in temperature between 10-20°C. Non-pharmaceutical interventions had a greater effect on Re with a decrease of 0.285 (95% CI 0.223; 0.347) for a 5th - 95th percentile increase in the government response index. The variation in the effective reproduction number explained by early government interventions was 6 times greater than for mean temperature. We find little evidence of meteorological conditions having influenced the early stages of local epidemics and conclude that population behaviour and governmental intervention are more important drivers of transmission.
Serving Open Data from mixed on-premise and cloud environment at the Finnish Meteorological Institute.
Authors: Visa Mikko , Tervo Roope
Published: June 2021

Finnish Meteorological Institute has a long history of open data. Partly as a result of the INSPIRE directive almost all important data was opened back in 2013. Because of this we have quite a long history of usage of the data and as well experience on technical solutions and user needs. The presentation will open up the current status and future development keeping in mind the upcoming WMO WIS2 development as well as the Open Data directive with its High Value Dataset proposal which will very likely feature meteorological datasets.

Data is provided via machine-readable interfaces as well as human usable web interfaces. We use on-premise storage and interfaces and in addition also offer cloud-based distribution such as the Amazon Public Dataset program. The current operational interfaces are based on WFS 2.0 and WMS. Most recently added datasets include weather and flood warnings in Common Alerting Protocol (CAP) format, black carbon measurements and radar data archive via Amazon S3 in GeoTIFF and HDF5 formats. There is development starting for providing data via even more developer-friendly interfaces such as the OGC Features API. Also new data is being added continuously based on our own and user needs.

An impact study has also been conducted for the year 2018 which reveals some findings on what data is used and how it impacts the users and their potential businesses. Also valuable information on the future needs of users was gathered and the most important findings of this study will be presented during the session.
SARAH-3 - a new satellite-based Cimate Data Record for surface radiation parameters from the CM SAF
Authors: Pfeifroth Uwe , Drücke Jaqueline , Trentmann Jörg , Hollmann Rainer
Published: June 2021

The EUMETSAT Satellite Application Facility on Climate Monitoring (CM SAF) generates and distributes high quality long-term climate data records (CDR) of energy and water cycle parameters, which are freely available.

In fall 2021, a new version of the “Surface Solar Radiation data set – Heliosat” will be released: SARAH-3. As the previous editions, the SARAH-3 climate data record is based on satellite observations from the first and second METEOSAT generations and provides various surface radiation parameters, including global radiation, direct radiation, sunshine duration, photosynthetic active radiation and others. SARAH-3 covers the time period 1983 to 2020 and offers 30-minute instantaneous data as well as daily and monthly means on a regular 0.05° x 0.05° lon/lat grid.

In this presentation, an overview of the SARAH climate data record and their applications will be provided. A focus will be on the SARAH-3 developments and improvements (i.e. improved consideration of snow-covered surfaces). First validation results of the new Climate Data Record using surface reference observations will be presented. Further, SARAH-3 will be used for the analysis of the climate variability in Europe during the last decades.

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Making ECMWF Open Data more easily accessible via cloud-based services
Authors: Wagemann Julia , Modigliani Umberto , Siemen Stephan , Baousis Vasileios , Pappenberger Florian
Published: June 2021

The European Centre for Medium-Range Weather Forecasts (ECMWF) is moving gradually towards an open data licence , aiming to make real-time forecast data available under a full, free and open data license by 2025. The introduction of open data policies lead in general to an increase in data requests and a broader user base. Therefore a much larger community of diverse users will be interested in accessing, understanding and using ECMWF Open Data (real-time). While an open data license is an important prerequisite, it does not automatically lead to an increased uptake of open data. In order to increase the uptake of (open) data, Wilkinson et al. (2016) defined the FAIR principles, which emphasize the need to make data better ‘findable’, ‘accessible’, ‘interoperable’ and ‘reusable’.

In 2019, we conducted a web-based survey among users of big Earth data to obtain a better understanding of users’ needs in terms of the data they are interested in, the applications they need the data for, the way they access and process data and the challenges they face. The results show that users are in particular interested in meteorological and climate forecast data, but facing challenges related to the growing data volumes, the data heterogeneity and the limited processing capacities. At the same time, survey respondents showed an interest in using cloud-based services in the near future, but expressed the need for an easier data discovery and the interoperability of data systems. Moreover, an ECMWF supported activity that made a subset of ERA5 climate reanalysis data available to the user community of the Google Earth Engine platform, revealed that interoperability of data systems is a growing bottleneck. 

Conclusions from both activities are helping ECMWF to define the way forward to make ECMWF Open Data (real-time) better accessible via cloud-based services. In this presentation we would like to share and discuss lessons learned to make open data more easily ‘accessible’ and ‘interoperable’ and the role cloud-based services play in doing so. We will also cover our future plans.
Why the use of weather and climate information is essential for SDG implementation
Authors: Griggs David
Published: June 2021

The United Nations 2030 Agenda for Sustainable Development is an ambitious plan for “people, “planet and prosperity”. At its core are the 17 Sustainable Development Goals (SDGs), the achievement of which is critically affected by weather and a changing climate. To that end emphasis has been given to delivering weather and climate services, with information packaged in ways that support timely decision making.

Yet often these approaches tend not to address which decision-making processes need what information, why they need it, or what form they need it in. They have also tended to be focussed on specific situations and SDGs (such as SDG 14, 15) where the need for weather and climate information is clear and obvious.

In this presentation, we will look at how weather and climate information impinges on different decision making contexts, requiring that information to be tailored in new ways. In doing so we will identify key action areas that need to be addressed to improve integration of weather and climate information into SDG decision making. 
Dynamics of key climate variables over Europe
Authors: Tzanis Chris , Kourtesiotis Christos , Philippopoulos Kostas
Published: June 2021

Temperature and humidity are key climatic variables for the assessment of climate variability. This study focuses on the climatic trends of temperature, specific and relative humidity both at the surface and in multiple pressure levels in the atmosphere. We present the first results of the analysis the dynamics of some key climate variables over Europe. The analysis was conducted for Europe, but it is focusing also on Greece. The main purpose of this study is to investigate whether possible changes in the basic climate variables exist over the recent years. 

Data from the ERA5 reanalysis product are used for the period 1979-2018 (40 years) with spatial resolution of 0.25° x 0.25°. The Sen’s slope estimator is used to identify the climate trends at each grid point and the Mann-Kendall statistical test was applied to detect statistically significant spatial and temporal changes for the examined domain. The results indicate statistically significant warming trends at the 99% level over land and sea at surface. Regarding Greece, statistically significant warming trends at the 99% level occur during summer. In addition, positive temperature trends are also presented over land and sea, in the troposphere, over the particular domain. In contrast, in the stratosphere, statistically significant cooling trends at the 99% level are observed. Additionally, the stratospheric cooling trends increase with increasing altitude in the atmosphere. Regarding the climatic trends of the specific humidity, mainly positive values prevail up to mid-troposphere. Finally, the climatic trends of the relative humidity exhibit positive and negative values due to the relationship of humidity and temperature.
Uncertainty Information & Non-Expert Decisions
Authors: Joslyn Susan
Published: June 2021

This talk will describe an experimental research demonstrating the benefit of including numeric uncertainty information in weather forecasts intended for non-experts. Our results suggest that numeric uncertainty estimates (e.g. 30% chance) allow users to better differentiate situations that do and do not require precautionary action while also increasing understanding and trust in the forecast. People appear to understand that all forecasts involve uncertainty and find forecasts that acknowledge it explicitly more plausible.  Moreover, these benefits are not dependent on higher education or special abilities—they extend to a broad range of users. However, this work also suggests that it is important to present numeric uncertainty estimates in a manner that is compatible with the way in which people process information and with their decision goal. 

 
Implementing Integrated Urban Services
Authors: Mills Gerald , Tarasova Oksana
Published: June 2021

Cities are a spatial nexus for a great number of environmental change issues on all scales from natural disasters like flooding, heat waves to poor air quality and to climate change. These issues are closely linked to the land-cover and land-use changes associated with urbanisation including the urban layout, the local economy, transportation networks and energy systems. The environmental services to deal with the risks associated with climate changes have developed independently with distinct scientific infrastructures for different domains/areas (e.g. observation systems and models to support meteorology, hydrology or air quality are disconnected) and specific audiences associated with stakeholder needs. The result is that the services are fragmented, the infrastructure is not shared, and new audiences/services are not identified. In cities where the drivers and risks associated with climate changes are bundled, integration of services is needed to manage risks and support urban resilience.

The WMO has embarked on a mission to develop integrated urban services (IUS) to bring together different environmental services to share data and tools and develop a common system of communications that support risk management and long-term planning at urban scales. An IUS is envisaged as an evolving system that is co-created with stakeholders to ensure a service that is adaptable to specific urban environmental concerns. The WMO has created guidelines for the creation of an IUS and a report that showcases IUS using demonstration cities. This presentation focuses on the final component of this mission, that of implementing an IUS. As part of this work, the WMO has reached out to a wide spectrum of urban stakeholders to identify needs, which can form a framework for next generation services. In addition, it will evaluate the costs and benefits of implementing IUS in different socioeconomic settings.
Higher airborne pollen concentrations correlated with increased SARS-CoV-2 infection rates, as evidenced from 31 countries across the globe
Authors: Damialis Athanasios
Published: June 2021

Pollen exposure weakens the immunity against certain seasonal respiratory viruses by diminishing the antiviral interferon response. Here we investigate whether the same applies to the pandemic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is sensitive to antiviral interferons, if infection waves coincide with high airborne pollen concentrations. Our original hypothesis was that more airborne pollen would lead to increases in infection rates. To examine this, we performed a cross-sectional and longitudinal data analysis on SARS-CoV-2 infection, airborne pollen, and meteorological factors. Our dataset is the most comprehensive, largest possible worldwide from 130 stations, across 31 countries and five continents. To explicitly investigate the effects of social contact, we additionally considered population density of each study area, as well as lockdown effects, in all possible combinations: without any lockdown, with mixed lockdown−no lockdown regime, and under complete lockdown. We found that airborne pollen, sometimes in synergy with humidity and temperature, explained, on average, 44% of the infection rate variability. Infection rates increased after higher pollen concentrations most frequently during the four previous days. Without lockdown, an increase of pollen abundance by 100 pollen/m3 resulted in a 4% average increase of infection rates. Lockdown halved infection rates under similar pollen concentrations. As there can be no preventive measures against airborne pollen exposure, we suggest wide dissemination of pollen−virus co-exposure dire effect information to encourage high-risk individuals to wear particle filter masks during high springtime pollen concentrations.
Wind droughts and winter cold threaten Europe's future energy security
Authors: van der Wiel Karin , Stoop Laurens , van Zuijlen Bas , Blackport Russel , van den Broek Mechteld , Selten Frank
Published: June 2021

To mitigate climate change a renewable energy transition is needed. Existing power systems will need to be re-designed to balance variable renewable energy production with variable energy demand. I will describe the meteorological sensitivity of a highly-renewable European energy system based on large ensemble simulations from two global climate models. From 2×2000 years of simulated weather conditions, we calculated daily wind and solar energy yields and energy demand and selected events of high societal impact: extreme high energy shortfall (residual load, i.e. demand minus renewable production). High energy shortfall days are characterized by large-scale high pressure systems over central Europe, with lower than normal wind speeds and below normal temperatures, driving up energy demands. The events typically occur mid-winter, locked to the coldest months of the year. Near-stationary high pressure situations occur that cause long lasting periods of high energy shortfall. A spatial redistribution of wind turbines and solar panels cannot prevent these high-impact events, options to import renewable energy from remote locations during these events are therefore limited. Projected changes due to climate change are substantially smaller than interannual variability. Future power systems with large penetration of variable renewable energy must be designed with these events in mind.
The state of weather, water and climate services in the U.S. and strategic challenges for the next decade: the perspective from the American Meteorological Society and U.S. National Weather Service
Authors: Farrar Mike
Published: June 2021

This keynote presentation will discuss several key applications and operational systems in the U.S. National Weather Service (NWS) and how they fit in with the broader mission of providing science-based weather, water and climate services to the nation. In addition, the future evolution of the National Centers for Environmental Prediction (NCEP) and NWS will be discussed as it relates to future goals and priorities related to people, science, technology, operational concepts and practices, and partnerships between government/public sector, the private sector, and academia. Also, in his role as the current President of the American Meteorological Society (AMS), Dr. Farrar will address the theme for the 2022 AMS annual meeting, "Environmental Security: weather, water and climate for a more secure world", which will explore the national and human security impacts from extreme weather and climate events and intersections with health, energy, food, and water security.
Improvement of seasonal forecast correction by using weather regimes
Authors: Viel Christian , Marson Paola , Grigis Lucas , Soubeyroux Jean-Michel
Published: June 2021

In order to develop seasonal forecast applications, raw forecast data generally need to be corrected to remove their systematic errors and drifts in time. In the climate community, methods based on quantile mapping techniques are quite common for their easy implementation. In the framework of the SECLI-FIRM project, we have tested a refinement of quantile mapping by conditioning the correction to weather regimes, in order to take large-scale circulation into account. For that purpose, we have used ADAMONT, a tool originally developed by Météo-France to correct climate projection scenarios. It was applied on four C3S seasonal forecast models over Europe, using ERA5 as a reference. Three parameters were treated at daily time-step: 2-metre temperature, precipitation and 10-metre wind-speed.

One of the main objectives of this study was to better understand the role weather regimes can play, if/when/where/for which parameter we gain in quality and predictability. For instance, a series of experiments were conducted on an idealized case of “perfect forecasts” of weather regimes, to point out the maximum benefits we could expect from the method.

Another focus of research was to test some strategies to optimize the positive impact of the introduction of weather regimes, by selecting members in one model ensemble or by using a multi-model approach. The selection was based on a sub-sampling of the best members in terms of weather regime frequency forecast, in order to determine the needed precision of weather regime forecast, for it to be useful in the correction.

We will present the main results of this work and some operational perspectives.