Identify cloud types and their characteristics
The EUMETCAL High Impact Weather group addressed a series of convective events over Europe during the summer 2010.
The EUMETCAL High Impact Weather group addressed a series of convective events over Europe between 5 and 9 August 2010. This events affected many countries from southern areas - Mediterranean/Balkans - to northern areas - Baltic/Scandinavia. In the 30 minute presentation the group analyzed the events, combining the analysis of convection, namely by satellite, with the impacts perspective.
Presentation with results on the occurences of overshooting tops in convective clouds in relation to severe weather.
Presentation given during the Convection Week 2011 by Petra Mikus, a young researcher from the Croatian Meteorological and Hydrological Service DHMZ. The presentation presents results on the occurrences of overshooting tops in convective clouds in relation to severe weather in Austria, Slovenia and Croatia.
Convective clouds can be characterized by three cloud top properties that can be detected by satellites and represented by respective tree RGB components which are discussed in the presentation.
Convective clouds can be characterized by three cloud top properties that can be detected by satellites and represented by respective tree RGB components;
1. Visible brightness, reflecting more solar radiation for thicker clouds with more water and ice (associated with RED color on RGB composites),
2. Cloud particle size and phase (water or ice), having larger drops with greater depth (associated with GREEN color on RGB composites).
3. Temperature, lover for higher tops (associated with BLUE color in RGB composites).
Microphysical processes within the clouds are specially discussed in this lecture, because they present great importance to the net reflectance of the clouds. Various combinations can be made of all the satellite channels to produce desired RGB combination (e.g. Airmass RGB and Dust RGB product) in order to track properties of interest like formation of fog, drizzle, rain clouds, intensive convective storms, etc. This presentation is given by Daniel Rosenfeld from Hebrew University of Jerusalem, Institute of Earth Sciences.
Because we don't know if the cloud observed from satellite is reaching ground or not, it is unrealistic to clam that we can identify fog only using satellite data.
Because we don't know if the cloud observed from satellite is reaching ground or not, it is unrealistic to clam that we can identify fog only using satellite data. Therefore presenter of this lecture is not presenting fog mapping derived only from satellite. Instead he is revealing cloud products extracted from MSG SEVIRI satellite imagery using NWCSAF software, concentrating on the fog or low level clouds category. Lecture is starting with some basic information about SAF nowcasting. After that main features of SAFNWC/MSG cloud algorithms, CM a (cloud mask), CT (cloud type) and CTTH (cloud top temperature and height) are given, step by step with validation results. Also there are examples with fog or low-level clouds situations, including example of automatic use for fog risk mapping.
Presentation on how to discriminate levels of dust and what are the global impacts of dust outbreaks.
Dust is a global issue with it\'s good and also less good sides. There are hundreds or even thousands of places on Earth where the dust can be lifted, nevertheless you need to have a dust source to create a dust outbreak. And these are indeed two needed ingredients for lifting dust in the air that must come together; strong surface winds (requires about 15 knots) and dust source (or hotspots). MSG satellite helps a lot to do much better hot spot climatology, and for that, product called Dust Microphisics RGB is widely used. It is derived from three MSG spectral channels. Red color corresponds to difference of channels IR12.0 and IR10.8, green color to the difference of channels IR10.8 and IR8.7 and blue color to the sole IR10.8 channel. In addition to this product Natural Color RGB is also used, but mostly for detection of dust outbreak over the ocean. In this lecture Jochen Kerkmann, from EUMETSAT, will try to describe dust source regions and dust climatology, how to detect better dust on satellite images, how to discriminate levels of dust and what are the global impacts of dust outbreaks. Also he will mention topics like synoptic patterns and diurnal cycles of dust outbrakes, cloud-dust interaction, forecasting of dust movement and will give a list of typical mesoscale phenomena that can cause dust outbreaks.
Presentation during the event week on Fog and Low Clouds in January 2009.
Vesa Nietosvaara presents fog forecasting process at FMI Aviation forecasting office.
Presentation during the event week on Fog and Low Clouds in January 2009.
Anna Eronn from the Swedish Hydrological and Meteorological Institute will talk about cold event Fog.
The most common way to detect fog and low clouds at night is by using of the brightness temperature difference between IR10.8 and IR3.9. Unfortunately this method does not work in very cold winter situations because the IR3.9 channel is very noisy for cold scenes. Therefore it is recommended to replace the IR3.9 with the IR8.7 channel which is significantly less noisy for cold scenes. The theory behind this and practical examples will be presented.
Presentation during the event week on Fog and Low Clouds in January 2009.
Nuno Moreira from Portugal will talk on how IM (Portugal) deals with fog, with focus in summer fog in comparison to (our) winter fog.
Presentation during the event week on Fog and Low Clouds in January 2009.
Jan Hemink from KNMI will give a practical session on fog in respect to the Aviation Meteorologist with an example from visibility observations and forecast of Fog at Amsterdam Airport Schiphol.
On a satellite image low layered Stratus is often compared to Fog. To actually know if there is Fog underneath this Stratus cover you have to know about the visibility. A problem than arises: When do we talk about Fog? The criteria for this is that the visibility should be below 1000 meters, but how do we defines this criteria during day and night.
The measurements of visibility in relation to the forecast will be a central point that is discussed in this presentation.
Presentation during the event week on Fog and Low Clouds in January 2009.
Paul de Valk, researcher of the remote sensing department at KNMI, will talk about radiation fog and shallow fog. Radiation fog is barely observable from satellite observations. Ground based observations are used to detect radiation fog. The satellite information is used to extrapolate the ground based point observations to a spatial distribution.
The forecaster is provided with information over fog favourable conditions deduced from observations and with information about visibility and ceiling. The tool is developed to support the forecaster in his decisions with respect to fog.
Presentation during the event week on Fog and Low Clouds in January 2009.
Practical session done by Stjepko Jancijev from the Croatian air-traffic control who will talk about Products and techniques used on Zagreb airport for fog forecasting. This talk will be followed by a colleague from the Croatian Weather Service DHMZ who will talk about the use of MSG and the derived Fog products in the operational shifts.
Presentation during the event week on Fog and Low Clouds in January 2009.
Jan Cermak (ETH) will talk about the operational detection of fog and low stratus from satellite data. The research presented my may help the forecasters and application experts to get out of the traditional thinking you cannot differentiate fog from low stratus with satellite images alone.