Discovery of a Water Vapor Layer in the Arctic Summer Mesosphere: Implications for Polar Mesospheric Clouds

• Main Authors: Summers, Michael E., Conway, R. R., Englert, C. R., Siskind, D. E., Stevens, M. H., Russell, III, J. M., Gordley, L. L., McHugh, M. J.
• Other Authors: NAVAL RESEARCH LAB WASHINGTON DC E O HULBURT CENTER FOR SPACE RESEARCH
• Format: Text
• Language: English
• Published: 2001
• Subjects: Atmospheric Physics; Meteorology; *CLOUDS; *WATER VAPOR; *MESOSPHERE; ICE; OCCULTATION; SUPERSATURATION; ATMOSPHERES; HALOGENS; SPECTROGRAPHY; HIGH RESOLUTION; LAYERS; REPRINTS; MIXING; MAHRSI(MIDDLE ATMOSPHERE HIGH RESOLUTION SPECTROGRAPH INVESTIGATION); ABUNDANCES; HALOE(HALOGEN OCCULTATION EXPERIMENT); PMC(POLAR MESOSPHERIC CLOD); NLCS(NOCTILUCENT CLOUDS); CRISTA(CRYOGENIC INFRARED SPECTROMETERS AND TELESCOPES FOR THE ATMOSPHERE); Arctic
• Online Access: http://www.dtic.mil/docs/citations/ADA526115; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA526115

We report the discovery of a layer of enhanced water vapor in the Arctic summer mesosphere that was made utilizing two new techniques for remotely determining water vapor abundances. The first utilizes Middle Atmosphere High Resolution Spectrograph Investigation (MAHRSI) OH measurements as a proxy for water vapor. The second is a reanalysis of Halogen Occultation Experiment (HALOE) water vapor data with a technique to simultaneously determine polar mesospheric cloud (PMC) ice particle extinction along with the water vapor abundance. These results reveal a narrow layer of enhanced water vapor centered between 82-84 km altitude and coincident with PMCs, that exhibits water vapor mixing ratios of 10-15 ppmv. This indicates that a higher degree of supersaturation is present in the PMC region, and that PMCs are thus more efficient at sequestering total water (both ice particles and vapor) within the layer, than previously believed. Published in Geophysical Research Letters, v28 n18 p3601-3604, 15 Sep 2001.