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UP: Umweltphysik
UP 14: Datenauswertung und Modellierung (Atmosphäre) I
UP 14.1: Vortrag
Dienstag, 19. März 2002, 14:45–15:00, HS 16
African and Oceanic Lightning and Sprites — •Martin Füllekrug1, Colin Price2, Yoav Yair3, and Earle Williams4 — 1Universität Frankfurt am Main, Institut für Geophysik, Feldbergstraße 47, 60323 Frankfurt am Main — 2Tel Aviv University, Department of Geophysics, Tel Aviv 69978, Israel — 3The Open University of Israel, 16 Klausner St., Tel Aviv 61392, Israel — 4Massachusetts Institute of Technology, Parsons Laboratory MIT 48-211, Cambridge MA 02139, USA
Extremely low-frequency magnetic field disturbances
from intense positive lightning discharges are
compared to the convective cloud cover
in central Africa, derived from infrared brightness
temperatures recorded on board the geostationary
satellite Meteosat during April 1998.
The daily integrated positive cloud to ground charge
transfer is well correlated with the
cloud cover at 15.5 km height, related to the charging
of the thundercloud.
The estimated charge density is used to estimate promising
locations for optical sprite observations in
the central Congo basin and Cameroon with 69 sprite
occurrences during an average night.
The electrodynamic properties of intense oceanic
lightning discharges are compared to intense
continental lightning discharges. Particularly
intense negative lightning discharges occur more
often over the oceans than over the continents
during April 1998. The intense lightning
discharges mainly occur in the late evening
associated with mesoscale convection.
These results strongly suggest that intense
negative oceanic lightning discharges
may produce mesospheric breakdown and oceanic sprites.