Water vapor measured by the Solar Occultation for Ice Experiment (SOFIE) instrument on the Aeronomy of Ice in the Mesosphere satellite has been validated in the vertical range 45-95 km. Precision estimates for SOFIE v1.022 H2O are similar to 0.2%-2.5% up to 80 km and degrade to similar to 20% at similar to 90 km. The SOFIE total systematic error from the retrieval analysis remains at similar to 3%-4% throughout the lower to middle mesosphere and increases from similar to 9% at 85 km to similar to 16% at 95 km. Comparisons with Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (ACE-FTS) and Microwave Limb Sounder (MLS) H2O show excellent agreement (0%-2%) up to 80 km in the Northern Hemisphere with rare exceptions. Percentage differences above similar to 85 km increase to similar to 20% or worse due largely to the low H2O volume mixing ratios in the upper mesosphere. For the Southern Hemisphere SOFIE is consistently biased low by 10%-20% relative to both ACE-FTS and MLS H2O. Slopes of SOFIE daily mean H2O isopleths on an altitude versus time cross section are used as an indicator of upwelling air motion. In the lower to middle mesosphere, the slope is the largest from mid-May to mid-June (maximum of similar to 1.5 cm/s), and then in July and August, it is reduced significantly. Both SOFIE and MLS daily mean H2O volume mixing ratios at the polar mesospheric cloud height increase rapidly from similar to 2.0 to similar to 5.0 ppmv prior to the solstice and then approach a near-constant but slightly increasing level (6.0-6.5 ppmv) throughout the season.
- ARCTIC SUMMER MESOSPHERE
- DIABATIC CIRCULATION