 |
| Titel |
Preliminary signs of the initiation of deep convection by GNSS |
| VerfasserIn |
H. Brenot, J. Neméghaire, L. Delobbe, N. Clerbaux, P. Meutter, A. Deckmyn, A. Delcloo, L. Frappez, M. Roozendael |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 13, no. 11 ; Nr. 13, no. 11 (2013-06-03), S.5425-5449 |
| Datensatznummer |
250018681
|
| Publikation (Nr.) |
 copernicus.org/acp-13-5425-2013.pdf |
|
|
|
|
|
| Zusammenfassung |
| This study reports on the exploitation of GNSS (Global Navigation
Satellite System) and a new potential
application for weather forecasts and nowcasting. We focus on GPS
observations (post-processing with a time resolution of 5 and 15 min and
fast calculations with a time resolution of 5 min) and try to establish
typical configurations of the water vapour field which characterise
convective systems and particularly which supply precursors of their
initiation are associated with deep convection. We show the critical role of GNSS
horizontal gradients of the water vapour content to detect small scale
structures of the troposphere (i. e. convective cells), and then we present
our strategy to obtain typical water vapour configurations by GNSS called
"H2O alert". These alerts are based on a dry/wet contrast taking place
during a 30 min time window before the initiation of a convective system.
GNSS observations have been assessed for the rainfall event of
28–29 June 2005 using data from the Belgian dense network (baseline from 5
to 30 km). To validate our GNSS H2O alerts, we use the detection of
precipitation by C-band weather radar and thermal infrared radiance (cloud
top temperature) of the 10.8-micrometers channel [Ch09] of SEVIRI instrument
on Meteosat Second Generation. Using post-processed measurements, our H2O
alerts obtain a score of about 80%. Final and ultra-rapid IGS (International GNSS Service) orbits have
been tested and show equivalent results. Fast calculations (less than 10 min) have been
processed for 29 June 2005 with a time resolution of 5 min. The mean bias (and standard deviation) between fast and reference
post-processed ZTD (zenith
total delay) and gradients are, respectively, 0.002 (± 0.008) m
and 0.001 (± 0.004) m. The score obtained for the H2O alerts
generated by fast calculations is 65%. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|