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| Titel |
Development of deep convection and identification of preliminary signs in water vapour structures by GNSS |
| VerfasserIn |
Hugues Brenot, Jean Neméghaire, Laurent Delobbe, Nicolas Clerbaux |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250052724
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| Zusammenfassung |
| Belgium is equipped with a network of 67 permanent GPS stations. The typical distance
between the stations ranges from 4 to 30 km which allows us to estimate the 2D field of the
zenith delay of the neutral atmosphere over Belgium, this is connected to the humidity field.
In addition, using horizontal gradients of delay, a precise location of water vapour structures
can be plotted from GNSS observations.
To study the convective rainfall event of the 28-29 June 2005, we measured GNSS
observations with a time resolution of 15 minutes. Considering all the synoptic
observations archived by the Royal Meteorological Institute of Belgium, we will briefly
present how our GNSS observations describe the meteorological situation. Our
presentation will focus on the interest of these observations for nowcasting. On the 29th
of June 2005 during a few hours, several clusters of convective cells developed
above the major part of Belgium. For each of these clusters we have identified the
same characteristic mechanism that we call “dry-wet contrast” of the humidity
field.
We will present the three criteria to use operational detections of these GNSS contrasts
for nowcasting. The first aspect is the definition of a meteorological warning using a
“dry-wet contrast” (criteria to obtain a contrast, “level of a warning”, and the role
of GNSS gradient in the precise location of a warning). The second aspect is the
validity of this warning referring to the development or not of this cluster. The third
element of the criteria is time: the delay between the time it takes to process GNSS
observations and establish a warning, in relation to the time of the development
of a cluster potentially identified by meteorological radar and satellites. Finally
we will present the score of our meteorological warning in a real-time situation. |
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