Synoptic Situation: Satellite Images, weather and basic numerical parameters
In the set of satellite images below several areas with convection can be seen emerging over Rumania, Poland and Hungary. A more closer look reveals that on the first day a frontal system is moving from west to east. The warm front shield shows the characteristics of convectivity with extreme cold cloudtop temperatures. This part of the system slowly wanders into Ukraine where it brings large amounts of rain and thunderstorms. In the later half of the case we see numerous of convective cells emerge over Central Europe in the cold air behind the frontal system. Striking is the influence the Carpathian Mountains have on the triggering of these cells. With the still easterly governing flow also these cells move further into Ukrain where they slowly die in the morning hours of 11th July 2004 as a result of the lacking insolation.
Meteosat 8 IR10.8μm: time sequence
The first chapter dealing with the synoptic situation describes the convective developments seen over Eastern Europe using plain Meteosat infrared 10.8 μm. The channel is appropiate as it pictures the ice phase of high clouds quite clearly. In a sequence of 15 minutes the relevant satellite image is presented and described.
Meteosat 8 Enhanced IR10.8μm: time sequence
In this chapter again Meteosat 8 infrared 10.8 μm is shown, but the images have been artificially colour enhanced. This will improve the discrimination of where the coldest cloudtops are found during the several convective stages. In a sequence of 15 minutes the satellite images are presented and described.
Meteosat 8 WV6.2μm: time sequence
The chapter presents the several convective developments over Eastern Europe using Meteosat 8 WV6.2 channel. The channel is suitable as it gives an idea of the upper tropospheric humidity (UTH) and gives a view of the upper air dynamics. 15 minutes sequence of images are presented.
Meteosat 8 Severe Convection RGB: time sequence
In this chapter the convective developments over Central and over South-East Europe is studied using the so-called
"severe convection RGB". On red the brightness temperature difference (BTD) of the two water vapour channels 6.2 and 7.3. On green the BTD of the infrared channels 3.9 and 10.8 and on blue the BTD of the two visible channels 1.6 and 0.6, respectively, are pictured.
Meteosat 8 Airmass RGB: time sequence
In this chapter the convection is studied using the
"Airmass RGB". Unlike the
"Severe Convection RGB" discussed previously this RGB does not use any visible channels making it thus also suitable to detect nighttime convection. The recipe of this RGB is that on red the brightness temperature difference (BTD) of the two water vapour channels 6.2 and 7.3 is pictured. On blue the BTD of the infrared channels 9.7 (Ozone channel) and 10.8 and finally on green WV channel 6.2. Using this channel combination different airmass are recognised. Polar and Tropical Airmass are pictured in blue and green, resp. The WV dark stripes discussed previously are pictured in red.
Meteosat 8 Dust RGB: time sequence
In this chapter the convection is studied using the
"Dust RGB". Although it would seem inappropiate to use the Dust RGB to monitor convection it can be of great help. Besides the detection the monitoring of dust the BTD of IR12.0 and IR10.8 (which is presented on the red beam in this RGB) allows a very clear discrimination between thick and thin cloudiness. This allows a clear discrimination with convection between the thick part of a cell and its surrounding thin cirrus shield.
Meteosat 8 IR10.8 and Geopotential Height 1000 hPa.: time sequence
In the following chapter the cloud configurations seen in satellite images are related to the basic field of surface pressure represented by geopotential height in 1000 hPa. 6-hourly sequences are shown.
Meteosat 8 IR10.8 and Geopotential Height 300 hPa.: time sequence
In the following chapter the cloud configurations seen in satellite images are related to the basic field of the upper level height in 300 hPa. 6-hourly sequences are shown.
Meteosat 8 IR10.8 and Surface observations: time sequence
In the following set of images observations of rain, hail and thunderstorms are related to the cloud configurations seen in satellite images in 3-hourly sequences.
Summary of the investigations in this chapter
The set of satellite images showed some severe convective development from different synoptic background moving in Ukrain on 9th and 10th July 2004. Most striking in the beginning of the loop where in the warm sector a synoptic scale convective area is observed. Being blocked by a belt of high pressure over Eastern Europe this convective area moves into Ukrain while it still enhances dramatically over Poland and Belarus bringing large amounts of rain and hail to these areas. Cloudtop temperatures of up to -70 degrees Celsius are observed. Meantime within the cold front we also see some enhancement of convection. Not bound to the insolation as the sun has already set some large cells are seen developing along the boundaries of moist and dry air (WV6.2 and Airmass). These cells also further develop and slowly die out in the morning hours while a ridge of high pressure is directing the cells towards Ukrain. Around noon on the 10th the last series of convection is developing along the carpathian mountain which contours can be seen quite well in all of the satellite images. The mountain ridge triggers a set of cell that develop rapidly and merge while moving east. Especially over the western part of Ukrain it causes some severe rainfall.