scholarly journals Predictability of the Strong Ural blocking Event in January 2012 in the Subseasonal to Seasonal Models of Europe and Canada

Atmosphere ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 538
Author(s):  
Dong Chen ◽  
Shaobo Qiao ◽  
Shankai Tang ◽  
Ho Nam Cheung ◽  
Jieyu Liu ◽  
...  
Keyword(s):  
Climate Change ◽  
East Asia ◽  
Development Stage ◽  
Weather Forecasts ◽  
Vorticity Advection ◽  
Medium Range ◽  
Ecmwf Model ◽  
Temperature Tendency ◽  
Blocking Event ◽  
Vorticity Tendency

The occurrence of a Ural blocking (UB) event is an important precursor of severe cold air outbreaks in Siberia and East Asia, and thus is significant to accurately predict UB events. Using subseasonal to seasonal (S2S) models of the European Centre for Medium-Range Weather Forecasts (ECMWF) and the Environment and Climate Change Canada (ECCC), we evaluated the predictability of a persistent UB event on 18 to 26 January 2012. Results showed that the ECCC model was superior to the ECMWF model in predicting the development stage of the UB event ten days in advance, while the ECMWF model had better predictions than the ECCC model for more than ten days in advance and the decaying stage of the UB event. By comparing the dynamic and thermodynamic evolution of the UB event predicted by the two models via the geostrophic vorticity tendency equation and temperature tendency equation, we found that the ECCC model better predicted the vertical vorticity advection, ageostrophic vorticity tendency, the tilting effect, horizontal temperature advection, and adiabatic heating during the development stage, whereas the ECMWF model better predicted the three dynamic and the two thermodynamic terms during the decaying stage. In addition, during both the development and decaying stages, the two models were good (bad) at predicting the vortex stretching term (horizontal vorticity advection), with the PCC between both the predictions and the observations larger (smaller) than +0.70 (+0.10) Thus, we suggest that the prediction of the persistent UB event in the S2S model might be improved by the better prediction of the horizontal vorticity advection.

scholarly journals Physical Process Contributions to the Development of a Super Explosive Cyclone Over the Gulf Stream

2021 ◽  
Vol 9 ◽  
Author(s):  
Shuqin Zhang ◽  
Chunlei Liu ◽  
Jianjun Xu ◽  
Shaojing Zhang ◽  
Ruoying Tang ◽  
...  
Keyword(s):  
Gulf Stream ◽  
Diabatic Heating ◽  
Rapid Development ◽  
Cyclonic Vorticity ◽  
Upper Troposphere ◽  
Explosive Cyclone ◽  
Weather Forecasts ◽  
Vorticity Advection ◽  
Medium Range ◽  
Water Vapor Convergence

Contributions of different physical processes to the development of a super explosive cyclone (SEC) migrating over the Gulf Stream with the maximum deepening rate of 3.45 Bergeron were investigated using the ERA5 atmospheric reanalysis from European Centre for Medium-Range Weather Forecasts (ECMWF). The evolution of the SEC resembled the Shapiro-Keyser model. The moisture transported to the bent-back front by easterlies from Gulf Stream favored precipitation and enhanced the latent heat release. The bent-back front and warm front were dominated by the water vapor convergence in the mid-low troposphere, the cyclonic-vorticity advection in the mid-upper troposphere and the divergence in the upper troposphere. These factors favored the rapid development of the SEC, but their contributions showed significant differences during the explosive-developing stage. The diagnostic results based on the Zwack-Okossi equation suggested that the early explosive development of the SEC was mainly forced by the diabatic heating in the mid-low troposphere. From the early explosive-developing moment to maximum-deepening-rate moment, the diabatic heating, warm-air advection and cyclonic-vorticity advection were all enhanced significantly, their combination forced the most explosive development, and the diabatic heating had the biggest contribution, followed by the warm-air advection and cyclonic-vorticity advection, which is different from the previous studies of ECs over the Northwestern Atlantic. The cross section of these factors suggested that during the rapid development, the cyclonic-vorticity advection was distributed and enhanced significantly in the mid-low troposphere, the warm-air advection was strengthened significantly in the mid-low and upper troposphere, and the diabatic heating was distributed in the middle troposphere.

Recent studies on troposphere delay modeling for SLR

2020 ◽  
Author(s):  
Mateusz Drożdżewski ◽  
Janina Boisits ◽  
Florian Zus ◽  
Kyriakos Balidakis ◽  
Krzysztof Sośnica
Keyword(s):  
Mapping Function ◽  
Terrestrial Reference Frame ◽  
Optical Observations ◽  
Weather Forecasts ◽  
Horizontal Gradients ◽  
Medium Range ◽  
Space Geodetic Techniques ◽  
Combined Solution ◽  
Parameterized Model ◽  
Ecmwf Model

<p>Recent studies on troposphere delay in Satellite Laser Ranging (SLR) show that the compliance of horizontal gradients of troposphere delay reduces the observation residuals, as well as improves the consistency between SLR results and other space geodetic techniques, all of which are essential for the realization of the terrestrial reference frame. In this work, we examine 3 novel approaches of troposphere delay modeling in SLR, with respect to the standard Mendes-Pavlis approach. We test Potsdam Mapping Function (PMF) with mapping function coefficients and linear horizontal gradients which are based on ERA5 reanalysis provided by the European Centre for Medium-Range Weather Forecasts (ECMWF) model with improved time and spatial resolution in comparison to ERA-Interim reanalysis. We also test a solution based on Vienna Mapping Function 3 for optical observations (VMF3o) which considers the separation of the mapping functions for hydrostatic and non-hydrostatic delays and horizontal gradients. Eventually, we test a solution based on Mendes – Pavlis model with a parameterized model for horizontal gradients based on the 16-year time series of horizontal gradients from PMF. To conduct this experiment, we use SLR observations to passive geodetic satellites LAGEOS-1 and LAGEOS-2. From differences of residual standard deviations for all proposed solutions, we observe an improvement of the SLR observation residuals, for low elevation angles above 10% and improvement of the consistency between estimated pole coordinates and the combined solution IERS-14-C04 series with respect to the currently recommended solutions that neglect the horizontal gradients in SLR solutions.</p>

scholarly journals Recent nationwide climate change impact assessments of natural hazards in Japan and East Asia

2021 ◽  
Vol 32 ◽  
pp. 100309
Author(s):  
Nobuhito Mori ◽  
Tetsuya Takemi ◽  
Yasuto Tachikawa ◽  
Hirokazu Tatano ◽  
Tomoya Shimura ◽  
...  
Keyword(s):  
Climate Change ◽  
East Asia ◽  
Natural Hazards ◽  
Climate Change Impact ◽  
Change Impact

Impact of planetary waves on infrasound propagation uncertainties

2021 ◽  
Author(s):  
Elisabeth Blanc ◽  
Patrick Hupe ◽  
Bernd Kaifler ◽  
Natalie Kaifler ◽  
Alexis Le Pichon ◽  
...  
Keyword(s):  
Wave Activity ◽  
Atmospheric Dynamics ◽  
Planetary Waves ◽  
Data Sets ◽  
Atmospheric Models ◽  
Period Range ◽  
Weather Forecasts ◽  
Atmospheric Disturbances ◽  
Medium Range ◽  
Model Improvement

<p>The uncertainties in the infrasound technology arise from the middle atmospheric disturbances, which are partly underrepresented in the atmospheric models such as in the European Centre for Medium-Range Weather Forecasts (ECMWF) products used for infrasound propagation simulations. In the framework of the ARISE (Atmospheric dynamics Research InfraStructure in Europe) project, multi-instrument observations are performed to provide new data sets for model improvement and future assimilations. In an unexpected way, new observations using the autonomous CORAL lidar showed significant differences between ECMWF analysis fields and observations in Argentina in the period range between 0.1 and 10 days. The model underestimates the wave activity, especially in the summer. During the same season, the infrasound bulletins of the IS02 station in Argentina indicate the presence of two prevailing directions of the detections, which are not reflected by the simulations. Observations at the Haute Provence Observatory (OHP) are used for comparison in different geophysical conditions. The origin of the observed anomalies are discussed in term of planetary waves effect on the infrasound propagation.</p>

Hochaufgelöste Simulation von meteorologischen Feldern in urbanen Räumen mit dem Weather Research and Forecasting (WRF) Modell

2021 ◽  
Author(s):  
Lukas N. Pilz ◽  
Sanam N. Vardag ◽  
Joachim Fallmann ◽  
André Butz
Keyword(s):  
Greenhouse Gas ◽  
Monitoring System ◽  
Weather Research And Forecasting ◽  
Gas Monitoring ◽  
Weather Forecasts ◽  
European Centre ◽  
Medium Range ◽  
Erste Ergebnisse ◽  
Weather Research

<p><span>Städte und Kommunen sind für mehr als 70% </span><span>der globalen, fossilen CO2-Emissionen</span><span> verantwortlich, sodass hier ein enormes Mitigationspotential besteht. Informationen über (inner-)städtische CO2-Emissionen stehen allerdings oft nicht </span><span>in hoher zeitlicher und räumlicher Auflösung</span><span> zur Verfügung und sind </span><span>meist</span><span> mit großen Unsicherheiten behaftet. Diese Umstände erschweren eine zielgerichtete und effiziente Mitigation im urbanen Raum. </span><span>Städtische Messnetzwerke können als unabhängige Informationsquelle einen Beitrag leisten, um CO2-Emissionen in Städten zu quantifizieren und Mitigation zu verifizieren</span><span>. </span><span>Verschiedene denkbare Beobachtungsstrategien sollten</span><span> im Vorfeld abgewägt werden, um urbane Emissionen bestmöglich, d.h. mit der erforderlichen Genauigkeit und </span><span>Kosteneffizienz</span><span> zu quantifizieren. So können Messnetzwerke die Basis für zielgerichtete und kosteneffiziente Mitigation legen.</span></p><p><span>Im Rahmen des Verbundvorhabens „Integrated Greenhouse Gas Monitoring System for Germany“ (ITMS) werden wir verschiedene Beobachtungsstrategien für urbane Räume entwerfen und mit Hilfe von Modellsimulation evaluieren und abwägen. Notwendige Voraussetzung für </span><span>die Evaluation der Strategien</span><span> ist eine akkurate Repräsentation des atmosphärischen Transports im Modell.</span></p><p><span>Diese Studie zeigt</span><span> erste Ergebnisse der hochauflösenden (1kmx1km) meteorologischen Simulationen für den Rhein-Neckar-Raum mit dem WRF Modell. </span><span>Die in WRF simulierten meteorologischen Größen werden für verschiedene Modellkonfigurationen mit </span><span>re-analysierten Daten des European Centre for Medium-Range Weather Forecasts (ECMWF) und ausgewählten Messstationen verglichen. Damit evaluieren wir </span><span>den Einfluss unterschiedlicher Nudging-Strategien, Parametrisierungen physikalischer Prozesse und urbaner Interaktionen</span><span> auf </span><span>die Modellperformance</span> <span>von</span><span> Lufttemperatur, Windrichtung, Windgeschwindigkeit und Grenzschichthöhe. Durch diese Analysen gewährleisten wir, dass die Simulation der Beobachtungsstrategien auf robuste</span><span>m</span><span> und realistische</span><span>m</span><span> atmosphärischen Transport basieren und schlussendlich repräsentative Empfehlungen für den Aufbau von Messnetzwerken liefern können. </span></p>

Aerosol Assimilation of lidar data from Satellite (AEOLUS) and Ground-based (EARLINET) instruments in COMPO-IFS.

2021 ◽  
Author(s):  
Julie Letertre-Danczak ◽  
Angela Benedetti ◽  
Drasko Vasiljevic ◽  
Alain Dabas ◽  
Thomas Flament ◽  
...  
Keyword(s):  
Quality Data ◽  
Lidar Data ◽  
Operational Model ◽  
Weather Forecasts ◽  
The Past ◽  
Medium Range ◽  
First Results ◽  
Monitoring Service ◽  
The Vertical Distribution ◽  
Good Quality Data

<p>Since several years, the number of aerosol data coming from lidar has grown and improved in quality. These new datasets are providing a valuable information on the vertical distribution of aerosols which is missing in the AOD (Aerosol Optical Depth), which has been used so far in aerosols analysis. The launch of AEOLUS in 2018 has increased the interest in the assimilation of the aerosol lidar information. In parallel, the ground-based network EARLINET (European Aerosol Research LIdar NETwork) has grown to cover the Europe with good quality data. Assimilation of these data in the ECMWF/CAMS (European Centre for Medium-range Weather Forecasts / Copernicus Atmosphere Monitoring Service) system is expected to provide improvements in the aerosol analyses and forecasts.<br><br>Three preliminary studies have been done in the past four years using AEOLUS data (A3S-ESA funded) and EARLINET data (ACTRIS-2 and EUNADIC-AV, EU-funded). These studies have allowed the full development of the tangent linear and adjoint code for lidar backscatter in the ECMWF's 4D-VAR system. These developments are now in the operational model version in research mode. The first results are promising and open the path to more intake of aerosol lidar data for assimilation purposes. The future launch of EARTHCARE (Earth-Cloud Aerosol and Radiation Explorer) and later ACCP (Aerosol Cloud, Convention and Precipitation) might even upgrade the use of aerosol lidar data in COMPO-IFS (Composition-Integrated Forecast system).<br><br>The most recent results using AEOLUS data (for October 2019 and April 2020) and using EARLINET data (October 2020) will be shown in this presentation. The output will be compared to the CAMS operational aerosol forecast as well as to independent data from AERONET (AErosol Robotic NETwork).</p>

Evaluierung des nichthydrostatischen mesoskaligen Modells GRAMM-SCI anhand der Richtlinie VDI 3783 Blatt 7/Evaluation of the nonhydrostatic mesoscale model GRAMM-SCI based on the guideline VDI 3783 Part 7

Gefahrstoffe ◽  
2020 ◽  
Vol 80 (07-08) ◽  
pp. 318-324
Author(s):  
D. Öttl
Keyword(s):  
Mesoscale Model ◽  
Weather Forecasts ◽  
European Centre ◽  
Medium Range

Aufgrund der komplexen Orografie in den Alpen sind einfache, auf diagnostischen Ansätzen beruhende Windfeldmodelle in Österreich kaum anwendbar. Daher wird in den meisten österreichischen Bundesländern das mesoskalige Modell GRAMM im Rahmen von Luftschadstoffuntersuchungen eingesetzt. In diesem Beitrag werden Ergebnisse der Modellevaluierung anhand jener drei Datensätze der Richtlinie VDI 3783 Blatt 7 präsentiert, die auf teils umfangreichen Messkampagnen basieren. Das Modell GRAMM wurde mittlerweile erweitert (Version GRAMM-SCI) und kann nun auch mit den Reanalysedaten ERA5 des Europäischen Wetterdienstes (European Centre for Medium-Range Weather Forecasts, ECMWF) angetrieben werden. Um die Qualität der ERA5-Daten zu prüfen, wurden zusätzliche Simulationen für die drei Evaluierungsdatensätze aus VDI 3783 Blatt 7 durchgeführt. Es zeigt sich, dass Modellsimulationen mit GRAMM-SCI, die auf ERA5-Daten basieren, die Strömungs- und Temperaturverhältnisse grundsätzlich gut wiedergeben. Allerdings sind die Abweichungen zu den Messungen der Sondermesskampagnen teilweise etwas zu groß, um die hohen Anforderungen von VDI 3783 Blatt 7 an die Modellergebnisse vollständig zu erfüllen.

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