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Implications of enhanced mesospheric water vapor observed by HALOE
Author(s) -
Siskind David E.,
Summers Michael E.
Publication year - 1998
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/98gl51608
Subject(s) - stratosphere , mesosphere , occultation , atmospheric sciences , altitude (triangle) , water vapor , environmental science , photodissociation , atmosphere (unit) , meteorology , physics , photochemistry , chemistry , astrophysics , geometry , mathematics
Recently reprocessed water vapor data from the Halogen Occultation Experiment (HALOE) on the UARS satellite show significant deviations from the expected constant value of 2*CH 4 + H 2 O. An unusual enhancement in the H 2 O is seen from 65–70 km which exceeds the stratospheric the value of 2*CH 4 + H 2 O by 0.6–0.8 ppmv. This is inconsistent with the conventional view of transport of H 2 O and CH 4 up from the lower stratosphere and photodissociation in the mesosphere and suggests the presence of another source of H 2 O. We re‐evaluate the hypothesis that there is an extraterrestrial source of water deposited at mesospheric altitudes. The HALOE data above 60 km provide stringent new constraints on the magnitude and altitude of such a source, but cannot rule out the possibility of a small contribution in the middle mesosphere.