Mapping Mariner 9 Dust Opacities

We present the results from a study of the spatial and temporal 9-μm opacity variation of the Martian 1971 global dust storm. T. Z. Martin (1986,Icarus66, 2–21) designed a procedure to calculate 9-μm opacities from the Viking IR Thermal Mapper data set. We have convolved the Mariner 9 IRIS data with...

Ausführliche Beschreibung

Gespeichert in:
Bibliographische Detailangaben
Veröffentlicht in:Icarus (New York, N.Y. 1962) N.Y. 1962), 1997-11, Vol.130 (1), p.115-124
Hauptverfasser: Fenton, Lori K., Pearl, John C., Martin, Terry Z.
Format: Artikel
Sprache:eng
Online-Zugang:Volltext
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
Beschreibung
Zusammenfassung:We present the results from a study of the spatial and temporal 9-μm opacity variation of the Martian 1971 global dust storm. T. Z. Martin (1986,Icarus66, 2–21) designed a procedure to calculate 9-μm opacities from the Viking IR Thermal Mapper data set. We have convolved the Mariner 9 IRIS data with Viking IRTM filter functions in order to use Martin's approach. We find a mean opacity of 0.32 and a modal opacity of 0.21. The resulting opacities are mapped and binned by solar longitude in order to investigate the structure of the 1971 dust storm. There is a diminishing spatial variation in opacity as the storm decays. The highest opacities occur in the southern tropics while the lowest opacities consistently appear in the southern polar region and near the equator. Hellas is relatively clear at the peak of the storm but becomes dustier than the rest of the planet as the storm dissipates. This behavior may be typical of Hellas and Argyre during global dust storms. In contrast, the Tharsis plateau is relatively dusty early in the mission but clears quickly. We have also calculated storm decay constants for different regions. The storm has a decay constant of 67 days in the 20°–30° S zone, 42 days in the 55°–65° S zone, and 46 days on the Tharsis plateau.
ISSN:0019-1035
1090-2643
DOI:10.1006/icar.1997.5810