Probabilistic wind speed forecasting in Hungary

Prediction of various weather quantities is mostly based on deterministic numerical weather forecasting models. Multiple runs of these models with different initial conditions result ensembles of forecasts which are applied for estimating the distribution of future weather quantities. However, the ensembles are usually under-dispersive and uncalibrated, so post-processing is required. In the present work Bayesian Model Averaging (BMA) is applied for calibrating ensembles of wind speed forecasts produced by the operational Limited Area Model Ensemble Prediction System of the Hungarian Meteorological Service (HMS). We describe two possible BMA models for wind speed data of the HMS and show that BMA post-processing significantly improves the calibration and precision of forecasts.Comment: 17 pages, 10 figure

Rövidtávú ensemble előrejelző rendszer kifejlesztése = Development of short-range ensemble weather prediction system

A kutatás célja egy, az ALADIN korlátos tartományú számszerű előrejelző modellen alapuló, rövidtávú valószínűségi (ensemble) előrejelző rendszer kifejlesztése volt. A megvalósítás során az alábbi kísérleteket végeztük el: (i) ARPEGE globális ensemble rendszer (PEARP) leskálázása az ALADIN modellel, ill. érzékenységi vizsgálatok a globális szinguláris vektorokkal. (ii) Az ECMWF ensemble rendszerből előállított szuper-ensemble elemeinek clusterezése, majd a clusterek reprezentatív tagjainak leskálázása az ALADIN modell segítségével. (iii) Perturbációk lokális származtatása az ALADIN modell szinguláris vektorai segítségével. Az elvégzett kísérletek alapján arra a következtetésre jutottunk, hogy a rövidtávú valószínűségi előrejelzések készítésének a legeredményesebb útja az ALADIN modellen alapuló kezdeti feltételek előállítása a szinguláris vektorok segítségével. Ugyanakkor a globális ensemble előrejelzések leskálázása ugyan korlátozott mértékben (például a szélsőséges jelenségek esetében), de érdemi hozzáadott értéket nyújthat az eredeti globális valószínűségi előrejelzésekhez képest. Ezen eredmények mérlegelése után döntöttünk arról, hogy az ALADIN perturbációk teljes alkalmazhatóságáig, már a projekt közvetlen lezárása után elkezdjük a francia PEARP rendszer operatív dinamikai leskálázását. Az eredményeket az előrejelző szakemberek rendelkezésére is fogjuk bocsátani ezzel is előkészítve a rövidtávú valószínűségi előrejelzések teljes operatív bevezetését Magyarországon. | The main objective the research was the development of a short-range ensemble prediction system, based on the ALADIN limited area model. The following experimentation was carried out in the framework of the OTKA research project: (i) Downscaling of the ARPEGE based global ensemble prediction system (PEARP) with the ALADIN model, as well as sensitivity experiments with global singular vectors. (ii) Downscaling of representative members of the super ensemble system created from ECMWF EPS members. (iii) The generation of local perturbations with the singular vectors of the ALADIN model. Based on these experiments it was found that the best method for the establishment of a short range ensemble prediction system is the creation of initial perturbations based on ALADIN singular vectors. At the same time it was revealed that the downscaling of global EPS systems can be also efficient in certain cases, typically in extreme weather situations (heavy precipitation and wind storms), therefore it is of interest to build-up such an operational system as a predecessor for the more advanced local-perturbation based system. Based on this judgement it was decided to start the quasi-operational downscaling of the French PEARP system with the help of the ALADIN model. This regular exploitation will significantly help in the smooth and step-by-step introduction of short range ensemble based probabilistic forecasting system in Hungary

Historical observation impact assessments for EUMETNET using the ALADIN/HU limited area model

Two historical Observing System Experiment (OSE) studies using the ALADIN limited area model and its assimilation system are described. The first study, using an OSE scenario that minimizes the impacts of observations through the lateral boundary conditions, demonstrated the importance of each assimilated terrestrial (radiosonde, aircraft, and wind profiler) observations on the analyses and short-range forecasts of the ALADIN/HU model and proved evidence, that the role of conventional observations cannot be even partly taken over by satellite measurements without degradation of the forecast quality. The second study demonstrated that the assimilation of radiosonde observations remains indispensable even with a progressively increasing amount of aircraft measurements

A szél hatása a késő-neogén–negyedidőszaki üledékképződésre és a domborzat alakulására a Magyar-középhegységben és előterében = The effect of the wind on the late Neogene and Quaternary sedimentation and morphological evolution of the Hungarian Central Range and of its foreland

Legfontosabb kutatási eredményeink: az eolikus üledékek és felszínek elterjedésének és korának meghatározása, megayardangok és plató helyzetű eolikus képződmények leírása, valamint a defláció meghatározó szerepének kimutatása a Dunántúl mai domborzatának, így a zalai és somogyi ún. meridionális völgyrendszer kialakításában is. A szélmarta kőzetfelszínek kozmogén 10Be izotópos korát a mélységprofilok menti mintavételezési módszer alkalmazásával sikerült meghatároznunk. Ezt a módszert korábban szélcsiszolta kőzetfelszíneken még nem alkalmazták; elsőként sikerült 1,5 millió éves szélcsiszolta sziklafelszínt datálnunk Európában. A Tapolcai- és Káli-medencék negyedidőszaki deflációs alacsonyodási rátája 40-75 m/My volt, ugyanakkor a kipreparálódó kvarcittömbök csupán 2-4 m-t pusztulnak évmilliónként. A különböző korú szélmarta felszíneken mért szélkarc irányok megfeleltek a mai ÉNy-ias széliránynak. Ezzel igazoltuk az állandónak tekinthető uralkodó szélirányt a negyedidőszak során. Az OSL kormeghatározással 8-80 ezer éves üledékeket sikerült datálnunk a Vértes környezetében. Az üledékanyag szemcséit a betemetődés előtt nem érte elegendő fény ahhoz, hogy a lumineszcens szignál teljesen lenullázódjon. Ezt valószínűleg a rövid szállítási távolság okozhatta. Ezzel magyarázható, hogy a vizsgált üledékek esetében a geomorfológia és a korábbi koradatok tükrében többnyire a centrális OSL kor adja meg a betemetődés korát. | Our most important results are: determination of the distribution and age of aeolian landforms and sediments and description of megayardangs and aeolian formations in plateau position. We demonstrated that deflation played a definitive role in the formation of the topography of Transdanubia and in the development of the radial valley system of Zala and Somogy countries. Age and denudation rate of the wind-abraded rock surfaces was determined using in situ produced 10Be depth profiles. This was the first application of this method on wind-polished rock surfaces, and the first time when a 1.5 million years old wind-abraded surface was dated in Europe. Quaternary deflational surface lowering of the Tapolca and Kál Basins was 40-75 m/My, while denudation rate of the cemented quartzite rock surfaces was only 2-4 m/My. We proved long term stability of north-westerly winds by the measurement of the direction of wind striations rock surfaces of different age. OSL ages of aeolian sediments in the Vértes foreland were 8-80 ky old. The sediments were not exposed to sunlight for enough time to anneal completely the luminescence signal, most probably because of the short distance of transportation. This is the reason why the central OSL ages provide the age of sedimentation, considering the geomorphology and previous age data as well

The worldwide C3S CORDEX grand ensemble: A major contribution to assess regional climate change in the IPCC AR6 Atlas

peer reviewedAbstract The collaboration between the Coordinated Regional Climate Downscaling Experiment (CORDEX) and the Earth System Grid Federation (ESGF) provides open access to an unprecedented ensemble of Regional Climate Model (RCM) simulations, across the 14 CORDEX continental-scale domains, with global coverage. These simulations have been used as a new line of evidence to assess regional climate projections in the latest contribution of the Working Group I (WGI) to the IPCC Sixth Assessment Report (AR6), particularly in the regional chapters and the Atlas. Here, we present the work done in the framework of the Copernicus Climate Change Service (C3S) to assemble a consistent worldwide CORDEX grand ensemble, aligned with the deadlines and activities of IPCC AR6. This work addressed the uneven and heterogeneous availability of CORDEX ESGF data by supporting publication in CORDEX domains with few archived simulations and performing quality control. It also addressed the lack of comprehensive documentation by compiling information from all contributing regional models, allowing for an informed use of data. In addition to presenting the worldwide CORDEX dataset, we assess here its consistency for precipitation and temperature by comparing climate change signals in regions with overlapping CORDEX domains, obtaining overall coincident regional climate change signals. The C3S CORDEX dataset has been used for the assessment of regional climate change in the IPCC AR6 (and for the interactive Atlas) and is available through the Copernicus Climate Data Store (CDS)

Mathematical problems in meteorological modelling

This book deals with mathematical problems arising in the context of meteorological modelling. It gathers and presents some of the most interesting and important issues from the interaction of mathematics and meteorology. It is unique in that it features contributions on topics like data assimilation, ensemble prediction, numerical methods, and transport modelling, from both mathematical and meteorological perspectives. The derivation and solution of all kinds of numerical prediction models require the application of results from various mathematical fields. The present volume is divided into three parts, moving from mathematical and numerical problems through air quality modelling, to advanced applications in data assimilation and probabilistic forecasting. The book arose from the workshop “Mathematical Problems in Meteorological Modelling” held in Budapest in May 2014 and organized by the ECMI Special Interest Group on Numerical Weather Prediction. Its main objective is to highlight the beauty of the development fields discussed, to demonstrate their mathematical complexity and, more importantly, to encourage mathematicians to contribute to the further success of such practical applications as weather forecasting and climate change projections. Written by leading experts in the field, the book provides an attractive and diverse introduction to areas in which mathematicians and modellers from the meteorological community can cooperate and help each other solve the problems that operational weather centres face, now and in the near future. Readers engaged in meteorological research will become more familiar with the corresponding mathematical background, while mathematicians working in numerical analysis, partial differential equations, or stochastic analysis will be introduced to further application fields of their research area, and will find stimulation and motivation for their future research work