HR: 0800h
AN: A21A-0711    [Abstracts]
TI: Low Humidity in the Tropical and Subtropical Atmosphere
AU: * Cau, P
EM: p.cau@reading.ac.uk
AF: University of Reading, Early Gate, PO Box 243, Reading, RG6 6BB United Kingdom
AU: Methven, J
EM: j.methven@reading.ac.uk
AF: University of Reading, Early Gate, PO Box 243, Reading, RG6 6BB United Kingdom
AU: Hoskins, B
EM: b.j.hoskins@reading.ac.uk
AF: University of Reading, Early Gate, PO Box 243, Reading, RG6 6BB United Kingdom
AB: The occurrence of dry intrusions in the tropical troposphere and their origins are investigated. The velocity fields from ERA-40 are used to calculate the back trajectories or air masses from radiosonde profiles. The humidity observed by the sonde is compared with humidity profiles reconstructed by taking ERA-40 specific humidity from the origin of the trajectories, reducing the value only if saturation occurs along the trajectory. The agreement between the two provides a validation of the trajectory technique used. The origin of dry air masses arriving in the tropical and subtropical region during January 1993 is discussed.
DE: 3337 Numerical modeling and data assimilation
DE: 3374 Tropical meteorology
DE: 0368 Troposphere--constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting