bluuebunny/crossref_metadata_2025 huggingface dataset:
UPAYA MENINGKATKAN PRESTASI BELAJAR PAI MATERI AKHLAK TERPUJI MELALUI PENERAPAN MODEL PEMBELAJARAN READING GUIDE PADA SISWA KELAS 4 DI SD 002 BELAKANG PADANG
Authors: JUMIAH JUMIAH
Published: June 2021

Penelitian ini bertujuan untuk meningkatkan prestasi belajar PAI materi akhlak terpuji dengan menggunakan model pembelajaran Reading Guide pada siswa kelas 4 SD Negeri 002 Belakang Padang Tahun 2015/2016.  Subyek penelitian sebanyak 15 orang, terdiri dari 8 siswa perempuan dan 7 siswa laki-laki. Penelitian ini dilaksanakan pada 12 sampai 28 Februari 2015. Penelitian ini merupakan Penelitian Tindakan Kelas yang terdiridari 2 siklus yang masing-masing siklus terdiri dari 4 tahap yaitu perencanaan, pelaksanaan, pengamatan, dan refleksi. Metode pengumpulan data yang digunakan yaitu tes tertulis dan dokumentasi. Analisis data pada penelitian ini yaitu dengan membandingkan pencapaian nilai dengan KKM dan ditandai dengan adanya peningkatan Kriteria Ketuntasan Klasikal pada setiap siklusnya. Hasil penelitian pada siklus I dan siklus II diperoleh data seperti berikut: KKM mata pelajaran Pendidikan Agama Islam adalah 70, sebelum menggunakan model pembelajaran reading guide hanya ada 40 % (6 siswa) yang tuntas, sedangkan 60% (9 siswa) belum memenuhi KKM. Setelah penggunaan model pembelajaran reading guide dalam pelajaran PAI pada siklus I diperoleh data 73% (11 siswa) tuntasdan 27% (4 siswa) tidak tuntas, sehingga terjadi peningkatan sebesar 33% dibandingkan pada pra siklus. Setelah itu dilakukan refleksi siklus I, terjadi peningkatan prestasi belajar pada siklus II yaitu sebesar 93% (14 siswa) tuntas dan 27% (4 siswa) belum memenuhi KKM. Dengan demikian dari siklus I ke siklus II terjadi peningkatan prestasi belajar sebesar 20 %. Prosentase Kriteria Ketuntasan Klasikal pada siklus II ini mencapai 93% dengan nilai rata-rata 75.33. Dengan kata lain sudah memenuhi indicator keberhasilan yang ditentukan yaitu prosentase Kriteria Ketuntasan Klasikal sebesar 85% dengan standar KKM 70.
PEMBINAAN KARAKTER MELALUI KEGIATAN PRAMUKA UNTUK PENINGKATAN DISIPLIN SISWA
Authors: MUSLIMIN MUSLIMIN , MISDAH MISDAH , WAHAB WAHAB
Published: June 2021

Artikel ini adalah hasil dari penelitian yang berjudul Pembinaan Karakter Melalui Kegiatan Pramuka Untuk Peningkatan Disiplin Siswa. Tujuan dari penelitian ini untuk menganalisis pembinaan karakter melalui kegiatan pramuka dalam meningkatkan disiplin siswa di Madrasah Ibtidaiyah Negeri 2 Pontianak Peneliti menggunakan metode penelitian menggunakan desain studi kasus (Case Study) dengan metode kualitatif sumber datanya pembina pramuka, (Observasi, Wawancara dan Dokumentasi). Adapun hasil penelitian ini (1) Bentuk pembinaan karakter melalui kegiatan pramuka dalam meningkatkan disiplin siswa yaitu Bentuk langsung dan tidak langsung, Bentuk mata pelajaran tersendiri dan terintegrasi dalam semua mata pelajaran, Bentuk kegiatan-kegiatan di luar mata pelajaran, Bentuk keteladanan, Bentuk nasehat-nasehat dan memberi perhatian, Bentuk reward dan punishment (2) Implementasi pembinaan karakter melalui kegiatan pramuka dalam meningkatkan disiplin siswa yaitu keimanan dan ketakwaan kepada Tuhan Yang Maha Esa, Kecintaan pada alam dan semesta manusia, Kecintaan pada tanah air dan bangsa, Kedisiplinan, keberanian, dan kesetiaan, Tolong-menolong, Bertanggung jawab dan dapat dipercaya, Jernih dalam pikiran, perkataan dan perbuatan, Hemat cermat dan bersahaja dan Rajin terampil dan gembira.
PENINGKATAN HASIL BELAJAR MATEMATIKA MATERI BILANGAN BULAT MELALUI PEMBELAJARAN JARAK JAUH DENGAN MEDIA VIDEO PEMBELAJARAN PADA SISWA KELAS VI C SD NEGERI WONOSARI I TAHUN PELAJARAN 2020/2021
Authors: MARWANI MARWANI
Published: June 2021

Penelitian ini bertujuan untuk mengetahui proses pelaksanaan pembelajaran jarak jauh dengan media video pembelajaran dan meningkatkan hasil belajar matematika materi bilangan bulat. Subyek penelitian adalah siswa kelas VI C SD Negeri Wonosari I, Gunungkidul. Subjek penelitian berjumlah 28 siswa terdiri dari 14 siswa laki-laki dan 14 siswa perempuan. Jenis penelitian yang digunakan adalah Penelitian Tindakan Kelas (PTK) dengan media Video Pembelajaran. Data dalam penelitian ini observasi, dokumentasi dan tes. Instrumen penelitian berupa lembar observasi dan soal tes. Analisa data menggunakan teknik deskripsi kualitatif. Berdasarkan hasil pengamatan diperoleh bahwa dalam proses pembelajaran matematika terlebih pembelajaran jarak jauh motivasi belajar siswa menurun . Hal tersebut mengakibatkan  hasil belajar siswa tidak maksimal, sehingga guru perlu mengadakan Penelitian Tindakan Kelas Penelitian Tindakan Kelas ini merupakan salah satu upaya meningkatkan hasil belajar matematika. Berdasarkan hasil analisa data dan pembahasan diperoleh kesimpulan bahwa hasil belajar matematika pada pembelajaran jarak jauh dengan media video pembelajaran  meningkat. Berdasarkan hasil penelitian dapat disimpulkan bahwa terjadi peningkatan hasil belajar matematika yang ditandai dengan kenaikan capaian nilai KKM, pada siklus I siswa yang mencapai KKM sebanyak 64,29 % meningkat menjadi  89,29% pada siklus II. Aktivitas dan motivasi belajar siswa juga mengalami peningkatan.
O QUE OS JOVENS DE ENSINO MÉDIO PENSAM E ANSEIAM SOBRE PROJETOS DE VIDA? UMA REVISÃO
Authors: Barbosa Jailma Maria Pimentel
Published: June 2021

Introdução: Existe uma necessidade do buscar perceber as diversas perspectivas teóricas sobre as juventudes no ensino médio, pois acredita-se ser um passo para compreender as expectativas sobre o futuro, e as vivências nesta etapa da escolaridade. Objetivo: Realizar uma revisão integrativa da literatura acerca dos pensamentos e anseios dos jovens do ensino médio sobre projetos de vida no Brasil e no mundo. Materiais e Métodos: Foram realizadas pesquisas nos bancos de dados como Periódico CAPES e Google acadêmico, nos últimos cinco anos. Os descritores utilizados foram: “aspiração” “concepção” “ensino médio” “juventude” “projeto de vida” e “aspiration” “conception” “High school” “Youth” “Life Project”. Foram selecionados oito artigos que se adequaram aos critérios estabelecidos. Resultados: Dos artigos analisados, foi possível observar que 60% dos artigos mostraram que há uma discrepante diferença de objetivos na relação entre a escola, as percepções dos jovens, as propostas de formação e os anseios e aspirações desses sujeitos na escola de ensino médio. Conclusão: Os artigos permitiram constatar que os jovens do ensino médio não têm aspirações de projetos de vida claramente definidas. A atenção desse público está voltada para o presente e as preocupações estão voltadas para relações amorosas e amistosas do momento. Além disso, as influências externas e as crenças gerais impactam diretamente na forma de pensar dos jovens do ensino médio e as aspirações de futuro, quando identificadas, terminam sendo frustradas.
Exploring the uncertainties in the aviation soot-cirrus effect
Authors: Righi Mattia , Hendricks Johannes , Beer Christof Gerhard
Published: June 2021

Abstract. A global aerosol-climate model, including a two-moment cloud microphysical scheme and a parametrization for aerosol-induced ice formation in cirrus clouds, is applied in order to quantify the impact of aviation soot on natural cirrus clouds. Several sensitivity experiments are performed to assess the uncertainties in this effect related to (i) the assumptions on the ice nucleation abilities of aviation soot; (ii) the representation of vertical updrafts in the model; and (iii) the use of reanalysis data to relax the model dynamics (the so-called nudging technique). Based on the results of the model simulations, a radiative forcing from the aviation soot-cirrus effect in the range of −35 mW m−2 to 13 mW m−2 is quantified, depending on the assumed critical saturation ratio for ice nucleation and active fraction of aviation soot, but with a confidence level below 95 % in several cases. Simple idealized experiments with prescribed vertical velocities further show that the uncertainties on this aspect of the model dynamics are critical for the investigated effect and could potentially add a factor of about two of further uncertainty to the model estimates of the resulting radiative forcing. The use of the nudging technique to relax model dynamics is proved essential in order to identify a statistically significant signal from the model internal variability, while simulations performed in free-running mode and with prescribed sea-surface temperatures and sea-ice concentrations are shown to be unable to provide robust estimates of the investigated effect. A comparison with analogous model studies on the aviation-soot cirrus effect show a very large model diversity, with a conspicuous lack of consensus across the various estimates, which points to the need for more in-depth analyses on the roots of such discrepancies.
Spatially consistent postprocessing of precipitation over complex topography 
Authors: Hemri Stephan , Bhend Jonas , Spirig Christoph , Furrer Reinhard , Moret Lionel , Liniger Mark A.
Published: June 2021

Over the last decade statistical postprocessing has become a standard tool to reduce biases and dispersion errors of probabilistic numerical weather prediction (NWP) ensemble forecasts. Most established postprocessing approaches train a statistical model using raw ensemble statistics on a typically small set of stations.  While raw ensemble statistics are available from high resolution NWP grid data, observations are missing at most grid points. Hence, the generation of spatial fields of forecast scenarios requires both some kind of interpolation and reshuffling of forecast quantiles based on a dependence template. The most widely used reshuffling approach, ensemble copula coupling (ECC), applies a reordering based on the raw ensemble rank order structure. ECC relies on the assumption that the spatial dependence structure of the raw ensemble is spatially consistent with the observed fields. This assumption may not always hold for hourly precipitation in particular over complex topography, since even high resolution models do not achieve a perfect representation of the real topography.

In this study, hourly CombiPrecip fields, which are a blend of precipitation observations from station and radar data, at a spatial resolution of 1 km over Switzerland serve as observations. Hourly precipitation raw ensemble forecast fields covering lead times up to 120 hours with a spatial resolution of 2 km are provided by COSMO-E. This enables us to postprocess hourly  COSMO-E ensemble precipitation forecasts over Switzerland at different spatial scales, from a single global ensemble model output statistics type model, over regional quantile regression  models up to grid point-wise local analog models. The mismatch in spatial resolution between COSMO-E and CombiPrecip as well as  the general issue of non-representative model topography over Switzerland’s complex topography may affect the spatial consistency of the (postprocessed) forecast fields. Starting with an analysis of systematic errors and spatial consistency of COSMO-E precipitation forecasts , we assess the potential for spatially multivariate postprocessing approaches, which are able to incorporate the spatial information from CombiPrecip and are yet simple and computationally efficient. To this end, we analyse the effects of using standard and new postprocessing model designs that vary in the (analog-based) selection of training data, spatial aggregation, postprocessing model parametrizations, and methods to obtain physically realistic forecast scenarios in space. 
A novel approach to surface reanalysis
Authors: Wahl Sabrina , Figura Clarissa , Keller Jan D.
Published: June 2021

Reanalysis is a procedure to merge numerical model integrations and observations to obtain a synergetic representation of the past climatological state of a system, e.g., of the atmosphere. An alternative to running a full reanalysis scheme is a so-called surface reanalysis. Here, an existing reanalysis is used as prior information (for the near-surface state). This first guess is then corrected in a data assimilation step preferrably by applying observations not used in the original assimilation. In such a scheme, an additional downscaling is often performed to enhance the spatial representation of the surface reanalysis.

We present here the development of a new approach aiming to establish such a data set based on the COSMO-REA6 regional reanalysis of the Hans-Ertel-Centre and Deutscher Wetterdienst (DWD). The data assimilation step is based on the operational Local Ensemble Transform Kalman Filter (LETKF) of DWD. While the data assimilation is often performed univariately in such surface reanalysis schemes, here we apply it to various parameters at once thus conserving the covariances among the parameters and allowing for a consistent multivariate utilization of the data. Further, this reanalysis will not be restricted to the ground level and near-surface parameters. Instead, it will be extended to the lower part of the boundary layer aiming at an improved representation of wind speeds in wind turbine hub heights especially relevant for renewable energy applications. The envisaged resolution is approximately 1km and therefore enables an enhanced representation of spatial variability and heterogeneity on small scales. In addition, the LETKF is an ensemble-based data assimilation scheme which also provides uncertainty estimates through an ensemble of the re-analyzed parameters which can also be used as input for downstream applications.
Evaluation of the use of radar-derived precipitation in water balance simulations: A case study in small-medium catchments in Saxony, Germany
Authors: Luong Thanh Thi , Vorobevskii Ivan , Pöschmann Judith , Kronenberg Rico
Published: June 2021

Water balance estimation/modeling is highly dependent on good-quality precipitation data and often lacks enough spatial information about it. Quantitative precipitation estimation (QPE) using radar data is recognized to have a good potential to significantly enhance the spatial depiction of precipitation compared to conventional rain gauge-based methods. However, precipitation measurements are often underestimated by wind drift or funnel evaporation, so that a correction such as Richter’s method is required before the data can be applied in the model. In this study, the Richter correction is applied for the first time to a radar-based QPE, namely RADKLIM-RW, to model water balance in ten selected catchments in Saxony, Germany. The modelled water balance components for the period 2001-2017 were evaluated by means of comparison of radar- and gauge-based precipitation inputs. The results showed that RADKLIM-RW was able to produce reliable simulations of discharge and water balance (KGE = 0.56 and 0.71 on the daily and monthly scales respectively). Application of the Richter correction improved the model performance by 5.5% and 8.9 % (for rain gauge-based and RADKLIM precipitation respectively). The study concluded that radar data as precipitation input to (pseudo)distributed hydrologic model shows immense potential to improve water balance simulations.

Hightlights:

Comparison of precipitation derived from sensor networks and radar imagery for small catchments

Evaluation of potential application of radar precipitation in water balance simulation at regional scale

Effect of wind correction (“Richter” correction) on radar precipitation products

Evaluating corrected precipitation on water balance processes

Keywords: HRU, radar climatology, RADKLIM RW (RADOLAN), Richter correction, Open sensor network, water balance simulation, BROOK90
Resource for teachers on the "Ocean and Cryosphere in a Changing Climate"
Authors: Lescarmontier Lydie , Guilyardi Eric , Klein Simon , Sadadou Djian , Tricoire Mathilde , Wilgenbus David
Published: June 2021

The essential role of education in addressing the causes and consequences of anthropogenic climate change is increasingly being recognised at an international level. The Office for Climate Education (OCE) develops educational resources and proposes professional development opportunities to support teachers, worldwide, to mainstream climate change education. Drawing upon the IPCC Special Report on the Ocean and Cryosphere in a Changing Climate, the OCE has produced a set of educational resources that cover the scientific and societal dimensions, at local and global levels, while developing students’ reasoning abilities and guiding them to take action (mitigation and/or adaptation) in their schools or communities. These resources include:

1. Ready-to-use teacher handbook that (i) target students from the last years of primary school to the end of lower-secondary school (aged 9 to 15), (ii) include scientific and pedagogical overviews, lesson plans, activities and worksheets, (iii) are interdisciplinary, covering topics in the natural sciences, social sciences, arts and physical education, (iv) promote active pedagogies: inquiry- based science education, role-play, debate, projectbased learning.

2. A Summary for teachers of the IPCC Special Report, presented together with a selection of related activities and exercises that can be implemented in the classroom.

3. A set of 10 videos where experts speak about a specific issue related to the ocean or the cryosphere, in the context of climate change.

4. A set of 4 multimedia activities offering students the possibility of working interactively in different topics related to climate change.

5. A set of 3 resources for teacher trainers, offering turnkey training protocols on the topics of climate change, ocean and cryosphere.
Statistical Analysis and Case Study of the Evaporation Duct over South China Sea
Authors: Hou Jou Ping , Chiao Mong-Ling
Published: June 2021

Atmospheric duct is a local inversion phenomenon that occurs in the lower atmosphere by the sea-air interaction. When it happens, electromagnetic waves are often affected by atmospheric refraction, resulting in deviations in the propagation path, and affects the effectiveness of communications and radar equipment. Atmospheric ducts often appear on the ocean in East Asia, especially the evaporation ducts in the low altitude. Evaporation ducts, which are caused by a rapid decrease in the refractive index of the lower atmosphere, are known to trap radio waves between the evaporation duct layer and the sea surface, and it exist over large bodies of water such as a sea or ocean, offers the possibility of long-range communication link because of a high percentage of occurrence with acceptable average duct height which allows trapping of radio wave propagation, primarily in the tropical regions of the world.

This study analyzes the evaporation duct height distribution that calculated by the WRF and the Paulus-Jeske evaporation duct model under two different weather patterns in 2017, and uses the high-resolution sounding data of the Dongsha Island, Taiping Island and R.V. Ocean Research I in the 2017 South China Sea Two-Island Monsoon experiment ( SCSTIMX ),and it was found that the results of the Paulus-Jeske evaporation duct model were lower than the results of the sounding data, indicating the Paulus-Jeske evaporation duct model is not applicable in the South China Sea atmosphere and walrus environment; in addition, after correcting the important parameters of the Paulus-Jeske evaporation duct model according to the characteristics of the South China Sea environment, the accuracy of the results can be greatly improved.
Investigating the effect of land-use change on the heat load within two Austrian cities
Authors: Goler Robert , Žuvela-Aloise Maja , Oswald Sandro , Holllósi Brigitta , Hahn Claudia , Kainz Astrid
Published: June 2021

As the majority of the population live in cities, it is important to understand the urban climate and how it can change in the future. Accordingly, the ACRP-funded project LUCRETIA investigates how land use and land cover determine local climate characteristics within cities in Austria. 

Historical land use data has been obtained for Graz and Vienna for a number of years and used as input into the microscale urban climate model MUKLIMO_3 to simulate both cities in conditions representing a typical summer day. In conjunction with the cuboid method, climate indices such as the average number of summer and hot days per year have been calculated to establish how the heat load changes from one year to another. Differences in the heat load have been related to changes in the land use focusing on (i) the change that occurs in situ and (ii) the change that occurs in the neighbourhood. 
 
It is shown that land use categories can be ordered according to their heat load, with categories containing larger amounts of greenery generally having lower heat loads. With the land use categories sorted in such a way, it enables a relatively quick assessment to be made of the effect of replacing one land use category with another, without having to employ expensive modelling tools. Furthermore, it is shown that land-use changes not only affect the heat load of the changed area in situ, but also the neighbourhood around where the change was made. This demonstrates that land-use changes may have a broader spatial impact than initially anticipated. The results from this study can serve as guidance for city planners regarding future land use and land cover changes.
Development of a low-cost X-band meteorological radar
Authors: Hrach Jan
Published: June 2021

We have undertaken a journey to develop a small X-band radar based on widely available commercial off-the-shelf (COTS) components. We have evaluated various radar transmitters, antenna and radome designs and sizes and we are currently operating the second-largest radar network in Europe, spanning 5 countries and consisting of 30 radars.

The final solution can be deployed by a small team in two days and operated without supervision with negligible maintenance and recurring costs. With approximately 120 kilometers of effective range and high refresh rate, it might be a good fit as an early warning radar, for areas with no current radar coverage or to fill gaps in larger networks; however, due to some limitations of the X band, namely higher attenuation in spatially distributed rain, it may not be a replacement of long-range observation radars.

In this work, we present an overview of our undertakings, technical solutions we have chosen and problems we have encountered. First, we cover transmitter technology selection, and discuss advantages and disadvantages of currently available magnetron and solid-state transmitters. Then we show the evolution of our antenna design, from 1-dimensional slotted waveguide to parabolic antennas with tapered beam. 

With large parabolic antennas, another problem arises: the mechanics of the radar cannot cope with the additional weight and angular momentum, thus we had to develop various mechanical supports and a custom rotator. This rotator can also tilt the antenna, effectively adding volumetric scanning; the tilting is also needed to cope with non-ideal radar locations, where the horizon is partially obscured, which are unfortunately common for a radar network with limited budget. Finally, we discuss design and material selection of our custom radomes, and present an overall experience with everyday running and maintaining the network.
Revisiting two-dimensional turbulence and mesoscale spectra
Authors: Larsén Xiaoli , Larsen Søren , Petersen Erik , Mikkelsen Torben
Published: June 2021

Two-dimensional (2D) turbulence is not only a basic research topic that needs further investigations, it is also relevant for wind energy applications as today’s wind farm clusters can be as large as thousands of kilometers squared and individual turbines hundreds of meters tall. This challenges the use of classical turbulence models applicable for scales smaller than ~1 h, or as denoted in Högström et al. (2002) the Kolmogoroff inertial subrange, the shear production range, and for ranges the spectral gap region.

This study revisits some key characteristics of 2D turbulence and interpretation of the physics behind it, including general literatures as well as a series of our studies in recent years (Larsén et al. 2013, 2016, 2021). This includes

The respective frequency/wave number range and the spectral behaviours for the wind speed: the synoptic scales where the spectral slope is -3, the mesoscale where the spectral slope is typically -5/3, and the gap region. We analyze at what scales the spectra meet and merge, and how the spectra are affected by weather types, seasons and stability.

The 2D-isotropy characteristics. We analyze how the longitudinal and lateral velocities correlate across the scales.

The application of stationarity. The validity of an assumption of stationary time series decides to how large scales we can perform the analysis of the longitudinal and lateral velocity components, the Taylor frozen hypothesis and 2D-isotropy.

The primary datasets are from several met stations over Denmark and the North Sea region, including both 10-min and sonic measurements from about 10 m up to 240 m.

 

References:

Högström U, Hunt J, Smedman AS (2002) Theory and measurements for turbulence spectra and variances in the atmospheric neutral surface layer. Boundary-Layer Meteorol 103:101–124

Larsén, X. G., Larsen, S. E., Petersen, E. L., & Mikkelsen, T. K. (2021). A Model for the Spectrum of the Lateral Velocity Component from Mesoscale to Microscale and Its Application to Wind-Direction Variation. Boundary-Layer Meteorology, 178, 415-434. https://doi.org/10.1007/s10546-020-00575-0

Larsén X. Larsen S. and Petersen E. (2016): Full-scale spectrum of the boundary layer wind. Boundary-Layer Meteorology, Vol 159, p 349-371

Larsén X., Vincent C. and Larsen S.E. (2013): Spectral structure of mesoscale winds over the water, Q. J. R. Meteorol. Soc., DOI:10.1002/qj.2003, 139, 685-700.
A Transformer model for predicting near-surface temperature and relative humidity
Authors: Alerskans Emy , Nyborg Joachim , Birk Morten , Kaas Eigil
Published: June 2021

It is a well-known fact that numerical weather prediction (NWP) models exhibit systematic errors, especially for near-surface variables. Reasons for this are, among other, the inability of these models to successfully handle sub-grid phenomena and shortcomings in the physical formulation of the model dynamics. Even though high-resolution regional NWP models usually have a spatial resolution of a few kilometers (or even finer) they generally exhibit local biases due to unresolved topography and obstacles. In order to obtain more local and site-specific forecasts post-processing methods can be used. Here, we have implemented a Transformer Neural Network model for post-processing 48-hour forecasts of 2 m temperature and relative humidity. The observational data used in this study consist of observations of 2 m air temperature and relative humidity from a network of private weather stations (PWSs). All in all, data from more than 1,000 locations are used. Forecast data from the Global Forecast System (GFS) model – such as temperature, relative humidity, wind speed and direction, radiation fluxes and upper level model fields – are also used as input to the model. The model is trained on 1.5 years of observational and forecast data and the performance is evaluated using an independent validation dataset of PWSs. We find that the Transformer post-processing model reduces the bias and standard deviation compared to the raw NWP forecast for a majority of stations. Furthermore, the model is validated on completely independent data from the Danish Meteorological Institute’s (DMI’s) observational network, where good results were obtained. Overall, the Transformer model produces forecasts that better match the locally observed weather.
A model for weather-related traffic variations and accident probabilities on roads
Authors: Becker Nico , Rust Henning , Ulbrich Uwe
Published: June 2021

Weather conditions affect both road traffic volume and the probability of road accidents. The aim of this study is improve the understanding of both effects as well as their interactions. In a first step, we develop generalized linear models for hourly road traffic counts at 1400 traffic stations on German federal roads and highways. It is distinguished between different vehicle types, including motorbikes, cars, delivery vans and trucks. Different meteorological variables are derived from reanalysis and radar data. The impacts of these variables on the predictive skill of the models is analyzed. In particular models for motorbike counts show large improvements, if meteorological predictors are added to the model. At weekends in the afternoon the mean squared errors of modeled motorbike counts are reduced by up to 60%. Temperatures around 25°C, no precipitation, low cloud cover and low wind speeds lead to the highest motorbike counts. In a second step, the information derived from the traffic models is used to improve models for hourly probabilities of road accidents. These models are based on police reports, which are available at the level of administrative districts, and can now explicitly take traffic volume into account. It is shown that in particular winter conditions like precipitation and freezing temperatures lead to a significant increase in accident probability. Especially the probabilities of roadway departures show an increase under such conditions. The models presented in this study are suitable for the integration in risk-based warning systems and have the potential to improve risk perception and behavior of warning recipients.
Communicating About Ideas for Innovation in Meteorology:  The Harry Otten Prize
Authors: Emch Pamela
Published: June 2021

The Harry Otten Prize for Innovation in Meteorology is awarded every two years at the Annual Meeting of the European Meteorological Society.  This prize, financed by an endowment created by Harry Otten, the founder of MeteoGroup, is oriented towards supporting individuals and small teams that might otherwise find it difficult to secure funding that can help them move their innovative, practical concept on a path towards implementation.  The process of running the competition for the prize, and of selecting the finalists and the ultimate winner, utilizes a variety of communication methods.  This presentation will provide a summary of the process for the Harry Otten Prize competition, focusing in particular on associated aspects of communication.
Lessons learned after two years of operational high-resolution (1,5 km) WRF simulations in Catalonia and a plan to increase their skill
Authors: Mercader Carbó Jordi , Bravo Blanco Manel , Moré Pratdesaba Jordi , Sairouni Afif Abdelmalik
Published: June 2021

The WRF-ARW has been the flagship mesoscale model in the Meteorological Service of Catalonia (SMC) since 2012. Several operational runs are performed daily (initialised at 00 and 12 UTC), using both the GFS and the IFS model for initial and boundary conditions, to account for uncertainties in the synoptic evolution. To provide more accurate forecasts to end-users, a convection-allowing simulation with a grid spacing of 1,5 km was added to the operational chain, starting in the summer of 2019. 

However, the verification results show that the improvement over its mother domain (a 3 km simulation with parameterised convection) is irregular because it does not happen for all the variables. For instance, the 2 m temperature forecasts are more reliable for the highest resolution domain but the wind speed at 10 m has a comparable skill. Regarding the precipitation, there is a very slight improvement only for high daily precipitation rates (50 or 80 mm) during some seasons; nevertheless, the results are worse in forecasting the occurrence of precipitation (that is, when considering low daily precipitation quantities). The comparison of the verification results among different model configurations (with various resolutions and initial conditions) can be easily performed by using a skill score table. This table and its design will also be presented in this session. 

Certainly, these results help to conceive strategies to enhance the skill of the 1,5 km simulations for some of the variables that arise as more inaccurate. For instance, it is evaluated to what extent using alternative static fields (changing the model topography or the land category) improves the forecasts of temperature, humidity or wind near the surface. Furthermore, the sensitivity of precipitation forecasts to several physics schemes is tested, seeking an enhancement of their skill. 
Measuring tropical rainfall with a dense Commercial Microwave Link network in Nigeria
Authors: Droste Arjan , Overeem Aart , Priebe Jan , Tricarico Daniele , Bogerd Linda , Leijnse Hidde , Uijlenhoet Remko
Published: June 2021

Accurate, global rainfall estimates are crucial for many fields, e.g. agriculture or disaster management. While developed countries typically enjoy a dense network of rain gauges and radar, in many less developed areas across the globe, precipitation measurement networks are sparse. To obtain rainfall data for these regions, opportunistic sensing techniques are especially valuable: the use of unconventional sources to extract valuable data that can allow us to estimate precipitation. One of the more prominent data sources is the use of Commercial Microwave Links –CMLs– to measure rainfall, by making use of the signal attenuation between cell phone towers. This method of estimating rainfall has been mostly tested and applied in developed countries that already have reasonable coverage of conventional precipitation measurements. However, the strongest benefits are to be gained in developing regions lacking such measurement networks, where CML data can make a big difference. Only few studies address this, generally using relatively small datasets.

This research focuses on tropical CML rainfall estimation in Nigeria. Nigeria has a dense network of CMLs and relatively few official measurement stations, making it an interesting area to study the effectiveness of CML precipitation measurements. Our dataset spans 4 regions within Nigeria, from the coast to inland, with several large cities (Lagos; Ibadan) as well as areas with less dense CML networks to investigate the influence. We employ the open-source R package RAINLINK to obtain 15-min rainfall maps based on data from several thousand CMLs during the rainy season. We optimise the most important RAINLINK parameters by comparing to rain gauge data, considering local network and environmental conditions. In addition, disdrometer data from Nigeria (or similar climates) are used to compute the values of the physically-based coefficients relating specific attenuation to rainfall rate.

 
Severe Weather Warnings: impact of an event vs. impact of a warning.
Authors: Willemse Saskia , Popovic Nathalie , Fuduric Nikolina , Bisang Léonie , Zachlod Cécile
Published: June 2021

The most important question a national weather service should ask itself in connection with its warning task is: "Do our warnings contribute to reducing the impact of extreme weather events?". A perfect impact forecast of an extreme weather event does not necessarily contribute to reduce the impact of the event. Even the most perfect warning, whether based on physical thresholds or on potential impact, is not a guarantee for a reduction of the impact of the warned extreme event. Only If the warning reaches the recipient in time, is understood and action is taken, is there a chance that the impact can be reduced, which means that the warning unfolds an impact. Therefore, if we want the recipient to understand the warnings and to know what action to take, we have to know what his needs are.

In this contribution we describe a method (“Jobs to be done”) with which we investigated the needs of the authorities in terms of severe weather warnings in Switzerland and we will present the results of this investigation. This method focuses our attention on those processes that are important to the authorities but unsatisfactorily fulfilled. Once isolated, we engage our experts in cooperation with the authorities to find optimal and innovative solutions through design thinking workshops. In the Swiss federal structure, the warning chain extends over all levels of the governance structure: the severe weather warnings are issued at federal level and transmitted to the Cantons, these can decide to add local information, particularly concerning impact, and transmit them to the communities and the population. In our investigation, we concentrated on the administrative authorities and on the cantonal coordination bodies of the fire brigades. The aim of this study is to find indications for optimising the warnings, in terms of content, representation and also distribution.

The investigation started in January 2021 with a series of interviews with seven natural hazard experts and six fire inspectors of different Cantons. Currently (April 2021) we are running two surveys in all Cantons and in June we plan two workshops with representatives of the Cantons and of the fire brigades together with collaborators of the National Weather Service MeteoSwiss (forecasters, developers and key accounts). 
Towards the operational use of tweets data in high impact weather scenarios: data mining and analytics in Basque Country.
Authors: Gaztelumendi Santiago
Published: June 2021

Although social media industry is now a very congested Marketplace, Twitter continues to maintain its status as a popular social media platform. There are 330 million monthly active users and 145 million daily active users on Twitter sending more than 6,000 tweets every second in the world. In Spain case 85% population are social media users, with around 5 million tweeter profiles for a population around 47 million. In the autonomous community of Basque country (2.17 million inhabitants) around 20% of citizens use Twitter.

Twitter is a social tool that enables users to post messages (tweets) of up to 280 characters supporting a wide variety of social communication practices including photo and video attach. The Basque Meteorology Agency @Euskalmet with more than 115,3 K followers is one of the most popular accounts in Basque Country. Twitter is not only an opportunity to instantaneous spread messages to people without intermediaries, but also as a potential platform for valuable data acquisition using tweeter API capabilities. In this contribution, we present a study of different aspects related to the operational use of Twitter data in the context of high impact weather scenarios at local level.

The most important activity in Euskalmet are actions in severe weather events. Before the event, mainly centered in forecast and communication, during the event in nowcast, surveillance and impact monitoring and after the event in post-event analysis. During all these complex processes real time tweets posted by local users offer a huge amount of data that conveniently processed could be useful for different purposes. For operational staff, working at office during severe weather episodes, is critical to understand the local effects that an adverse phenomenon is causing and the correct perception of the extent of impact and social alarm. For this purposes, among others, different information associated with posted tweets can be extracted and exploited conveniently. In this work, we present some results that demonstrate how different data mining and advances analytics techniques can be used in order to include social media data information for different tasks and particularly during high impact weather events.

In this paper we summarize our experience during a proof of concept project for automatic real time tweeter analysis and the development of an operational tool for tweeter API data exploitation in the Basque Country. We present the main challenges and problems that we have had to face, including how to deal with the lack of geolocation information, since in the case of the Basque country, as in other parts of the world, tweets containing geotags are the exception, not the rule.
Time-dependent solutions for daily-periodic slope flows driven by surface energy budget
Authors: Marchio Mattia , Farina Sofia , Zardi Dino
Published: June 2021

Diurnal wind systems generated from daytime heating and nighttime cooling of valleys and slopes are a very common feature over mountainous terrains. Despite their frequent occurrence and relevance for a variety of applications, ranging from pollutant transport to convection initiation, slope winds are far from being fully understood and still provide an open research topic.

A well-known steady-state analytical model is the one developed by Prandtl (1942). Then, a first time-dependent analytical model was proposed by F. Defant (1949) and later extended by Zardi and Serafin (2015). These models provide slope-normal profiles of temperature and along-slope wind velocity as a response to a sinusoidal forcing representing the surface temperature. The resulting profiles exhibit sinusoidal oscillations at every distance from the surface, although with different phase lags under different regimes, determined by different combinations of slope angle and stability of the unperturbed ambient atmosphere. As a consequence, they can not explain the observed differences between daytime upslope and nighttime downslope winds in terms of magnitude and height of the peak of wind velocity, as well as the different timing characterising nighttime, daytime, and the two reversal phases.

In the present work, the solutions derived in Zardi and Serafin (2015) are extended to include a more realistic daily-periodic surface forcing taking into account the daily evolution of the surface temperature computed on the basis of a surface energy budget. Incoming solar radiation is represented by means of a Fourier series expansion derived from well-established relationships taking into account latitude, day of the year, slope angle, exposition and other astronomical and atmospheric factors. Based on these expansions, suitable harmonic solutions are derived for the heat flux into the ground and sensible heat flux in the atmosphere, and hence for the daily evolution of slope-normal profiles of along-slope wind velocity and potential temperature.

References:

Prandtl L. 1942. Führer durch die Strömungslehre, Chapter 5. Vieweg und Sohn: Braunschweig, Germany. [English translation: Prandtl L. 1952. Mountain and valley winds in stratified air, in Essentials of Fluid Dynamics: 422–425. Hafner Publishing Company: New York, NY]

Defant F. 1949. Zur Theorie der Hangwinde, nebst Bemerkungen zur Theorie der Berg- und Talwinde. Arch. Meteorol. Geophys. Bioklimatol. A 1: 421–450

Zardi D., Serafin S. 2015. An analytic solution for time‐periodic thermally driven slope flows. Q. J. R. Meteorol. Soc., 141, 1968–1974, https://doi.org/10.1002/qj.2485
A Budget-Based Turbulence Length Scale Diagnostic
Authors: Reilly Stephanie , Bašták Ďurán Ivan , Schmidli Juerg
Published: June 2021

The most frequently used boundary-layer turbulence parameterization in numerical weather prediction (NWP) and general circulation (GC) models are turbulence kinetic energy (TKE) based schemes. However, these parameterizations suffer from a potential weakness, namely the strong dependence on an ad-hoc quantity, the so-called turbulence length scale. The turbulence length scale is used to parameterize the molecular dissipation of TKE and is required to calculate the turbulence exchange coefficients. Traditional turbulence length scale formulations are designed for scales that are located above the energy production range of the turbulence spectra, hence the transfer of TKE across scales is not considered. However, as computational power increase, there is an increase in the potential for simulating turbulence at resolutions that are within the energy production range of turbulence. This is a gray zone problem. In order to represent turbulence processes accurately at these resolutions, the transfer of TKE across scales needs to be accounted for. For this purpose, a new turbulence length scale diagnostic, that can be used in the development of new turbulence length scale formulations, has been developed.  The new diagnostic uses the budget of TKE and the budgets of scalar variances to estimate the effective dissipation rate, which encapsulate the sum of the molecular dissipation and the cross-scale TKE transfer. The effective dissipation rate is then associated with the new scale-dependent turbulence length scale. Several idealized LES cases, simulated with the MicroHH model, are used to diagnose the turbulence length scale. It has been found that in the gray zone of turbulence the new turbulence length scale strongly depends on the horizontal grid spacing, and that this scale-dependence is also height-dependent. The new diagnostic is used for the evaluation of existing turbulence length scale formulations.
Assessment of the WRF model performance in air temperature and wind speed simulation over a complex Antarctic topography
Authors: Matějka Michael , Láska Kamil , Jeklová Klára , Hošek Jiří
Published: June 2021

The Antarctic Peninsula experiences a strong climate variability which is well reflected in glacier mass balance and state of the other cryospheric components. A better insight into the interactions of the atmosphere and the cryosphere can be obtained using numerical atmospheric models. In the presented work, the Weather Research and Forecasting (WRF) model at 700 m horizontal resolution was validated in the northern part of James Ross Island, Antarctic Peninsula. The model topography was based on the Reference Elevation Model of Antarctica. Sea ice cover was updated daily using high–resolution satellite observations. The WRF output was compared with air temperature, wind speed and wind direction observations from multiple automatic weather stations located in a complex topography and a mosaic of land cover types of Ulu Peninsula. Two periods in 2019/2020 representing contrasting seasons (summer and winter) were selected to identify possible seasonal effects on model accuracy. The three WRF boundary layer schemes (MYJ, MYNN, QNSE) were tested and the spatial and seasonal variability in their performance was evaluated. Simulated air temperatures were in very good agreement with measurements (mean bias –1.7 °C to 1.4 °C). The model was within 2 °C of observations in 47–72 % of the winter period and in 66–79 % of the summer period. An exception was a strong air temperature inversion at two winter days when the model accuracy decreased at low–altitude sites. Additional analysis of the WRF output revealed a good skill in simulating near–surface wind speed with higher correlation coefficients in winter (0.81–0.93) than in summer (0.41–0.59). Wind speed mean bias was mostly lower than 2.5 m·s–1, but higher wind speed overestimation was found at a coastal site during the winter validation period. The model successfully captured wind direction, showing only small differences to the observed values. Finally, the model accuracy at coastal and low–altitude sites was found to be more sensitive to the strength of synoptic–scale wind than at higher–altitude sites.  