Identify and interpret broad scale, synoptic and mesoscale systems
Andreas Wirth (ZAMG) presents the benefits of analysing the water vapour imagery to diagnose synoptic structures and weather patterns.
Water vapor (WV) imagery is very useful when it comes to visualize zonal and meridional transport of air masses, but it is also suited to get a rapid overview on vertical transport processes. This characteristic makes WV-imagery extremely helpful when it comes to diagnose fronts and cyclogenesis.
The presentation will focus on the dynamics of cyclogenesis and fronts and how they are reflected in WV-imagery. The concept of relative streams will be introduced in the context of cyclogenesis, ana- and kata fronts.
Meteorological products based on WV absorption bands such as the Total Precipitable Water product will be introduced and their usefulness will be demonstrated on case examples.
Christo Georgiev (NIMH) presents influence of synoptic and mesoscale dynamical process, through water vapour imagery, on the intensification of wildfires.
Studies of large fires in Australia, Tasmania, USA and Southeastern Europe have shown a link between fire activity and dry stratospheric intrusions with downward transport of energy and momentum down to the lower troposphere. In such cases the rapid increase of fire activity was accompanied by a dry band in satellite Water Vapour (WV) imagery, which is indicative of pronounced descent of upper-tropospheric or stratospheric air which is normally much dryer than the lower tropospheric one and has much higher potential vorticity. When these descending air masses, reach the Earth’s surface they affect the wind speed, moisture and ozone concentration, which could generate a spike in fire activity.
Case-study examples of such severe events over areas of Central and Eastern Mediterranean are considered in the presentation. Combination of WV imagery, satellite soundings and satellite estimations of fire radiative energy contribute to better understanding of dry stratospheric intrusion depth and related dynamical processes, which govern the intensification of wildfire occurrence and spread.
Christo Georgiev (NIMH) discusses the effect of vorticity on tropical cyclones and development of severe thunderstorms, through the scope of water vapour imagery.
Water vapour (WV) images provide useful information to anticipate the effects of upper-level dynamic environment on the intensity of a tropical cyclone (TC) as well as on its extratropical transition (ET), a gradual process in which a TC loses tropical characteristics and becomes more extratropical in nature. Analyses of WV imagery shows that during ET stage over subtropical areas, advection of potential vorticty anomaly can influence the ET and control the process.
Large amounts of water vapour, originated by TCs may be involved in transfer of moisture by planetary waves, associated with ET developments and give rise to a narrow regions of strong meridional water vapour flux. The presentation shows WV imagery synoptic-scale analysis, which shows supply with additional large amount of moisture of an existing already favourable convective environment. The
combination lead into an environment with very high CAPE and potential to accelerate upward, acquiring kinetic energy and forming strong vertical motions in a deep tropospheric layer. The process is illustrated by a case of catastrophic hailstorm over Bulgaria, Eastern Mediterranean.
Nataša Strelec-Mahović (EUMETSAT) shows and analyses several cases of water vapour structures in the atmosphere using satellite imagery.
Features occurring in the WV6.2μm images indicate the processes going on in the atmosphere, since these dark (dry) and white (moist) structures result from a combination of vertical motion, moisture advection and horizontal deformation within the mid and upper troposphere. Frequently, water vapour images reveal structures such as dark stripes, mountain wave signatures, or circular or spiral formations known as water vapour eyes, eddies or vortices. We will look at how these features can be used as tracers of three-dimensional atmospheric motions on the meso- and synoptic scale and how they relate to e.g. jet-streams, upper-level lows or turbulence.
Christian Herold (DWD) investigates the usefulness of IASI L2 products in nowcasting, detecting and analyzing sting jets in rapid cyclogenesis.
Strong winds southwest of the center of a Shapiro-Keyser-Cyclone are often associated with a cold conveyor jet or a sting jet. The sting jet is a strong mesoscale flow with a very high damage potential. It is a massive challenge for NWP and forecasters to correctly predict a sting jet. The question is, can IASI profiles help forecasters for a better prediction of such mesoscale severe wind events connected with sting jets? In this specific context, some case studies will be presented.
Bryan Guarante (University of Wisconsin) uses a COMET course to explain the usefulness of analysing water vapour images with a goal of assessing the NWP fields.
In dynamically-active regions of the atmosphere, water vapour imagery approximates the same surface as the 1.5PVU height or pressure surface. Because of this, we can take advantage of the WV channels to find areas of mismatch between the NWP and the real atmosphere to adjust our synoptic scale forecasts.
Pieter Groenemeijer (ESSL) presents his findings in using low-level moisture proxy data from polar orbiting satellites at European Severe Storms Laboratory training events.
In preparation for MTG data, ESSL is carrying out a series of expert workshops and Testbeds in collaboration with EUMETSAT. At both event types, the increased capabilities of detecting low-level moisture from geostationary orbit, which the MTG program will enable, have received a high amount of attention. In our presentation, we will discuss a number of convective storm cases that were studied using proxy data from polar-orbiting instruments, such as MODIS. One of the ways to visualize low-level moisture is by depicting the ratio of the 0.91 and 0.85 μm channels with an intuitive color scale. We will discuss to what extent this and other proxies for low-level humidity can be used to anticipate the presence of a crucial ingredient for severe deep, moist convection...
Wilfried Jacobs (DWD) introduces the water vapour channels in the 2022 EUMeTrain Water Vapour Event Week.
The target group of this presentation is participants that are not familiar or do not feel familiar enough for understanding the presentations during the entire week. The first presentation deals with basics of vapour water channels in satellite products. First, the principle of radiation and radiation transfer will be outlined briefly and put in relation to wave lengths of imagers and vertical sounders by considering weighting functions. The second part deals with some examples by using single channels. Finally, corresponding composites (RGBs) and their applications will explained in detail.
Izolda Marcinoniene gives a talk on the synoptic background for strong winds in Lithuania.
In Lithuania, very strong winds (≥28m/s) are usually caused by Atlantic cyclones. Fifty-five cases in 173 sites have been registered during the period 1961–2021. Even a few cases with very powerful winds (>40 m/s) were observed. According to statistics, most events occur during the cold season and bring significant damage. Thus, a short summary will be presented. Additionally, the typical cyclone track and synoptic situation will be shown in this presentation.
Javier Garcia-Pereda and Mate Mile give an overview on the NWC-SAF high resolution wind product and its application.
The “NWC SAF/HRW High Resolution Winds” provides a detailed calculation of Atmospheric Motion Vectors locally and in near real time. It calculates the AMVs considering cloud and humidity patterns in up to seven different MSG/SEVIRI channels (HRVIS, VIS06, VIS08, WV062, WV073, IR108, IR120), together with NWP data and the “NWC SAF Cloud products (Cloud type, Cloud top temperature and height)”.
It considers up to two tracer scales (Basic and detailed), two tracer determination methods (Gradient and tracer characteristics), two tracking methods (Euclidean distance or cross correlation), and two Height level assignment methods (Brightness temperature interpolation method and Cross correlation contribution method). As other AMV products worldwide it also includes a quality control flagging based on the Quality Indicator Method developed at EUMETSAT.
NWC SAF/HRW product can be useful in Nowcasting applications in synergy with other data available to the forecaster: monitoring of low level convergence, divergence at the top of developed systems, or other cases of small scale circulation or wind singularities. It can also be used as an input in analysis and forecasting applications like NWP models. The development and main characteristics of the product are explained with examples, useful for the potential users to know what the product can offer. The validation results related to the latest version on the product (HRW v4.0) are also explained.
The role of the Atmospheric Motion Vectors (AMV) in the modern data assimilation systems is evident nowadays. The AMVs – along with satellite observations – have an important key for our operational ALADIN data assimilation system as well. In the framework of the EUMETSAT SAF High Resolution Winds (HRW) products had been developed by AEMET for Nowcasting and Very Short Range Forecasting purposes. The HRW products provide quasi real time data of AMVs from MSG HRVIS and IR10.8 channels every hour in a day. A collaboration between AEMET and OMSZ have been focused to compare the benefit of the operationally used AMVs (received through the EumetCAST) with the newly processed HRW winds. Recent work was an extensive evaluation and monitoring of the assimilation and forecast system. The impact of the AMV winds was examined using different diagnostic techniques, verifications tools and case studies. The first results are promising regarding the use of the HRW AMV. The statistical scores on the full domain showed neutral or slightly positive impact in most of the parameters and the experiment based on HRW AMV data provided better estimate of extreme precipitation events.
David M. Schultz gives a presentation on the different conceptual models approaches concerning occlusion processes in frontal systems.
This talk presents new conceptual models in cyclone structures and evolutions. How does the large-scale flow in which the cyclone is embedded determine the type of frontal evolution that occurs? How does the air flow through cyclones, and what can this tell us about the possibility for damaging winds at the surface? This talk concludes with general principles for how forecasters can improve their skill through the use of conceptual models in operational forecasting.
Fernando Prates gives a presentation on forecasting the tracks of tropical cyclones (TC). He gives presents the TC products delivered by ECMWF.
In this module the importance of forecasting tropical cyclones (TC) is briefly discussed. An overview is given of the recent developments in the forecast systems at ECMWF with impact on the forecast of TCs, including the recent change in the model’s resolution and the implementation of the Ensemble Data Assimilation. At the present time, any TC formed in the forecast system can be identified using a tracker developed at ECMWF. How does it work and what kind of products that can be derived from it is discussed. Some examples are also presented to highlight the model's ability to forecast the genesis of TCs. Finally the statistics of the forecast performance for TCs is discussed.