A compact receiver system for simultaneous measurements of mesospheric CO and O 3

Abstract. During the last decades, ground-based microwave radiometry has matured into an established remote sensing technique for measuring vertical profiles of a number of gases in the stratosphere and the mesosphere. Microwave radiometry is the only ground-based technique that can provide vertical profiles of gases in the upper stratosphere and mesosphere both day and night, and even during cloudy conditions. Except for microwave instruments placed at high-altitude sites, or at sites with dry atmospheric conditions, only molecules with significant emission lines below 150 GHz, such as CO, H2O, and O3, can be observed. Vertical profiles of these molecules can give important information about chemistry and dynamics in the middle atmosphere. Today these measurements are performed at relatively few sites; more simple and reliable instrument solutions are required to make the measurement technique more widely spread. This need is urgent today as the number of satellite sensors observing the middle atmosphere is about to decrease drastically. In this study a compact double-sideband frequency-switched radiometer system for simultaneous observations of mesospheric CO at 115.27 GHz and O3 at 110.84 GHz is presented. The radiometer, its calibration scheme, and its observation method are presented. The retrieval procedure, including compensation of the different tropospheric attenuations at the two frequencies and error characterization, are also described. The first measurement series from October 2014 until April 2015 taken at the Onsala Space Observatory, OSO (57° N, 12° E), is analysed. The retrieved vertical profiles are compared with co-located CO and O3 data from the MLS instrument on the Aura satellite. The data sets from the instruments agree well with each other. The main differences are the higher OSO volume mixing ratios of O3 in the upper mesosphere during the winter nights and the higher OSO volume mixing ratios of CO in the mesosphere during the winter. The low bias of mesospheric winter values of CO from MLS compared to ground-based instruments was reported earlier.

[1]  A. E. Barrington,et al.  Radio Measurement of the Atmospheric Ozone Transition at 101.7 GHz , 1968 .

[2]  P. Hays,et al.  Observation of mesospheric ozone at low latitudes. , 1973 .

[3]  F. Shimabukuro,et al.  Microwave Measurement of Mesospheric Carbon Monoxide , 1976, Science.

[4]  R. W. Haas,et al.  Absolute calibration of millimeter-wavelength spectral lines , 1976 .

[5]  K. Kunzi,et al.  Atmospheric CO volume mixing ratio profiles determined from dround-based measurements of the J = 1 → O and J = 2 → 1 emission lines , 1982 .

[6]  Guy Brasseur,et al.  Aeronomy of the Middle Atmosphere: Chemistry and Physics of the Stratosphere and Mesosphere , 1984 .

[7]  H. Müller,et al.  Submillimeter, millimeter, and microwave spectral line catalog. , 1985, Applied optics.

[8]  B. Connor,et al.  Pressure broadening of millimeter-wave ozone lines by atmospheric gases , 1986 .

[9]  E. Lobsiger,et al.  Ground-based microwave radiometry to determine stratospheric and mesospheric ozone profiles , 1987 .

[10]  P. Solomon,et al.  A ground-based technique for millimeter wave spectroscopic observations of stratospheric trace constituents , 1988 .

[11]  A. Hedin.  Extension of the MSIS Thermosphere Model into the middle and lower atmosphere , 1991 .

[12]  P. Hartogh,et al.  Simultaneous Water Vapour And Ozone Measurements with Millimeterwaves In The Stratosphere And Mesosphere , 1991, [Proceedings] IGARSS'91 Remote Sensing: Global Monitoring for Earth Management.

[13]  B. Connor,et al.  Ground‐based microwave monitoring of stratospheric ozone , 1992 .

[14]  Hans J. Liebe,et al.  Propagation Modeling of Moist Air and Suspended Water/Ice Particles at Frequencies Below 1000 GHz , 1993 .

[15]  M. Janssen.  Atmospheric Remote Sensing by Microwave Radiometry , 1993 .

[16]  P. Rosenkranz,et al.  Absorption of Microwaves by Atmospheric Gases , 1993 .

[17]  B. Connor,et al.  Ground-based microwave observations of ozone in the upper stratosphere and mesosphere , 1994 .

[18]  A. Parrish.  Millimeter-wave remote sensing of ozone and trace constituents in the stratosphere , 1994, Proc. IEEE.

[19]  Variability of mesospheric CO in the fall and winter as observed with ground‐based microwave radiometry at 115 GHz , 1995 .

[20]  P. Rosenkranz.  Water vapor microwave continuum absorption: A comparison of measurements and models , 1998 .

[21]  Per Jarlemark,et al.  Ground‐based microwave radiometry and long‐term observations of atmospheric water vapor , 1998 .

[22]  B. Connor,et al.  Intercomparison of remote sounding instruments , 1999 .

[23]  Hideo Ogawa,et al.  Ground-based millimeter-wave observations of ozone in the upper stratosphere and mesosphere over Tsukuba , 1999 .

[24]  Clive D Rodgers,et al.  Inverse Methods for Atmospheric Sounding: Theory and Practice , 2000 .

[25]  D. Marsh,et al.  The existence of a tertiary ozone maximum in the high‐latitude middle mesosphere , 2001 .

[26]  Laurence S. Rothman,et al.  The HITRAN molecular spectroscopic database: edition of 2000 including updates through 2001 , 2003 .

[27]  R. Garcia,et al.  Longest continuous ground‐based measurements of mesospheric CO , 2003 .

[28]  S. A. Buehlera,et al.  ARTS , the atmospheric radiative transfer simulator , 2004 .

[29]  CO as an important high‐altitude tracer of dynamics in the polar stratosphere and mesosphere , 2004 .

[30]  Gang Li,et al.  The HITRAN 2008 molecular spectroscopic database , 2005 .

[31]  Stefan Buehler,et al.  Qpack, a general tool for instrument simulation and retrieval work , 2005 .

[32]  L. Froidevaux,et al.  Ground‐based microwave ozone radiometer measurements compared with Aura‐MLS v2.2 and other instruments at two Network for Detection of Atmospheric Composition Change sites , 2007 .

[33]  S. Chapman.  Discussion of memoirs. On a theory of upper-atmospheric ozone , 2007 .

[34]  L. Froidevaux,et al.  Comparison and synergy of stratospheric ozone measurements by satellite limb sounders and the ground-based microwave radiometer SOMORA , 2007 .

[35]  Nathaniel J. Livesey,et al.  Validation of middle‐atmosphere carbon monoxide retrievals from the Microwave Limb Sounder on Aura , 2007 .

[36]  Brian J. Drouin,et al.  Validation of Aura Microwave Limb Sounder stratospheric ozone measurements , 2008 .

[37]  P. Hartogh,et al.  Ozone distribution in the middle latitude mesosphere as derived from microwave measurements at Lindau (51.66 N, 10.13 E) , 2009 .

[38]  Guy P. Brasseur,et al.  Aeronomy of the Middle Atmosphere , 2009 .

[39]  Anders Emrich,et al.  Water Vapor Radiometer for ALMA , 2009 .

[40]  J. Notholt,et al.  Atmospheric Measurement Techniques The ground-based MW radiometer OZORAM on Spitsbergen – description and status of stratospheric and mesospheric O 3-measurements , 2010 .

[41]  H Zirath,et al.  MMIC-Based Components for MM-Wave Instrumentation , 2010, IEEE Microwave and Wireless Components Letters.

[42]  V. M. Shulga,et al.  3-mm wave spectroradiometer for studies of atmospheric trace gases , 2010 .

[43]  J. Thepaut,et al.  The ERA‐Interim reanalysis: configuration and performance of the data assimilation system , 2011 .

[44]  Justus Notholt,et al.  Observation of strato-mesospheric CO above Kiruna with ground-based microwave radiometry – retrieval and satellite comparison , 2011 .

[45]  C. Emde,et al.  ARTS, the atmospheric radiative transfer simulator, version 2 , 2011 .

[46]  P. Bernath,et al.  Technical Note: A trace gas climatology derived from the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) data set , 2011 .

[47]  B. Funke,et al.  Six years of mesospheric CO estimated from ground-based frequency-switched microwave radiometry at 57° N compared with satellite instruments , 2012 .

[48]  C. Hoffmann.  Application of CO as a tracer for dynamics in the polar winter middle atmosphere: A study based on ground-based microwave observations in Kiruna , 2012 .

[49]  R. Garcia,et al.  A review of CO2 and CO abundances in the middle atmosphere , 2013 .

[50]  D. Newnham,et al.  Atmospheric ozone above Troll station, Antarctica observed by a ground based microwave radiometer , 2013 .

[51]  K. Hocke,et al.  Intercomparison of stratospheric ozone profiles for the assessment of the upgraded GROMOS radiometer at Bern , 2013 .

[52]  D. Newnham,et al.  Mesospheric CO above Troll station , Antarctica observed by a ground based microwave radiometer , 2013 .

[53]  Time series inversion of spectra from ground-based radiometers , 2013 .

[54]  N. Kämpfer,et al.  GROMOS-C, a novel ground-based microwave radiometer for ozone measurement campaigns , 2015 .

[55]  L. Froidevaux,et al.  Unusual stratospheric ozone anomalies observed in 22 years of measurements from Lauder, New Zealand , 2015 .

[56]  T. Clarmann,et al.  Trend analysis of the 20-year time series of stratospheric ozone profiles observed by the GROMOS microwave radiometer at Bern , 2015 .

[57]  C. Boone,et al.  Detecting physically unrealistic outliers in ACE-FTS atmospheric measurements , 2015 .