A compact receiver system for simultaneous measurements of mesospheric CO and O3

Geoscientific Instrumentation, Methods and Data Systems

V. M.Shulga¹  O. M.Christensen¹  P.Eriksson¹  P.Forkman¹  B.Billade¹  V.Vassilev¹ 

DOI  :  10.5194/gi-5-27-2016

学科分类：天文学(综合)

来源: Copernicus Publications

【 摘 要 】

During the last decades, ground-based microwave radiometry has matured intoan established remote sensing technique for measuring vertical profiles of anumber of gases in the stratosphere and the mesosphere. Microwave radiometryis the only ground-based technique that can provide vertical profiles ofgases in the upper stratosphere and mesosphere both day and night, and evenduring cloudy conditions. Except for microwave instruments placed athigh-altitude sites, or at sites with dry atmospheric conditions, onlymolecules with significant emission lines below 150 GHz, such as CO,H₂O, and O₃, can be observed. Vertical profiles of these moleculescan give important information about chemistry and dynamics in the middleatmosphere.

Today these measurements are performed at relatively few sites; more simpleand reliable instrument solutions are required to make the measurementtechnique more widely spread. This need is urgent today as the number ofsatellite sensors observing the middle atmosphere is about to decreasedrastically. In this study a compact double-sideband frequency-switchedradiometer system for simultaneous observations of mesospheric CO at115.27 GHz and O₃ at 110.84 GHz is presented.

The radiometer, its calibration scheme, and its observation method arepresented. The retrieval procedure, including compensation of the differenttropospheric attenuations at the two frequencies and error characterization,are also described. The first measurement series from October 2014 untilApril 2015 taken at the Onsala Space Observatory, OSO (57° N,12° E), is analysed. The retrieved vertical profiles are comparedwith co-located CO and O₃ data from the MLS instrument on the Aurasatellite. The data sets from the instruments agree well with each other. Themain differences are the higher OSO volume mixing ratios of O₃ in theupper mesosphere during the winter nights and the higher OSO volume mixingratios of CO in the mesosphere during the winter. The low bias of mesosphericwinter values of CO from MLS compared to ground-based instruments wasreported earlier.

【 授权许可】

Unknown