MIAWARA-C, a new ground based water vapor radiometer for measurement campaigns

Straub, C.; Murk, Axel; Kämpfer, Niklaus

doi:10.5194/amt-3-1271-2010

Cited by 48 publications

(65 citation statements)

References 28 publications

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“…A value of 0.8 is used here as it limits the contribution of a priori information in the retrieved profile and has been used for sev- eral similar ground-based instruments (e.g. Hoffmann et al, 2011;Straub et al, 2010). This cut-off gives a range of approximately 16-54 km.…”

Section: Example Fits and Properties Of Retrieved Statesmentioning

confidence: 99%

Ozone profiles above Kiruna from two ground-based radiometers

et al. 2016

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Abstract. This paper presents new atmospheric ozone concentration profiles retrieved from measurements made with two ground-based millimetre-wave radiometers in Kiruna, Sweden. The instruments are the Kiruna Microwave Radiometer (KIMRA) and the Millimeter wave Radiometer 2 (MIRA 2). The ozone concentration profiles are retrieved using an optimal estimation inversion technique, and they cover an altitude range of ∼ 16-54 km, with an altitude resolution of, at best, 8 km. The KIMRA and MIRA 2 measurements are compared to each other, to measurements from balloon-borne ozonesonde measurements at Sodankylä, Finland, and to measurements made by the Microwave Limb Sounder (MLS) aboard the Aura satellite. KIMRA has a correlation of 0.82, but shows a low bias, with respect to the ozonesonde data, and MIRA 2 shows a smaller magnitude low bias and a 0.98 correlation coefficient. Both radiometers are in general agreement with each other and with MLS data, showing high correlation coefficients, but there are differences between measurements that are not explained by random errors. An oscillatory bias with a peak of approximately ± 1 ppmv is identified in the KIMRA ozone profiles over an altitude range of ∼ 18-35 km, and is believed to be due to baseline wave features that are present in the spectra. A time series analysis of KIMRA ozone for winters [2008][2009][2010][2011][2012][2013] shows the existence of a local wintertime minimum in the ozone profile above Kiruna. The measurements have been ongoing at Kiruna since 2002 and late 2012 for KIMRA and MIRA 2, respectively.

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Section: Example Fits and Properties Of Retrieved Statesmentioning

confidence: 99%

Ozone profiles above Kiruna from two ground-based radiometers

et al. 2016

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“…Two ground-based microwave radiometers participated to the campaign, namely the Water Vapor Millimeter-wave Spectrometer (WVMS) permanently deployed by the US Naval Research Laboratory (NRL) at TMF and the portable MIddle Atmosphere WAter vapor RAdiometer (MIAWARA-C) from the University of Bern, Switzerland (Straub et al, 2010). During a 5-month validation campaign the standard deviation of the MLS (version 2) -WVMS differences was shown to be 5 % from 26-70 km and the systematic difference was within 8 % throughout this altitude range.…”

Section: Microwave Radiometersmentioning

confidence: 99%

Validation of MIPAS IMK/IAA temperature, water vapor, and ozone profiles with MOHAVE-2009 campaign measurements

et al. 2012

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Abstract. MIPAS observations of temperature, water vapor, and ozone in October 2009 as derived with the scientific level-2 processor run by Karlsruhe Institute of Technology (KIT), Institute for Meteorology and Climate Research (IMK) and CSIC, Instituto de Astrofísica de Andalucía (IAA) and retrieved from version 4.67 level-1b data have been compared to co-located field campaign observations obtained during the MOHAVE-2009 campaign at the Table Mountain Facility near Pasadena, California in October 2009. The MIPAS measurements were validated regarding any potential biases of the profiles, and with respect to their precision estimates. The MOHAVE-2009 measurement campaign provided measurements of atmospheric profiles of temperature, water vapor/relative humidity, and ozone from the ground to the mesosphere by a suite of instruments including radiosondes, ozonesondes, frost point hygrometers, lidars, microwave radiometers and Fourier transform infrared (FTIR) spectrometers. For MIPAS temperatures (version V4O T 204), no significant bias was detected in the middle stratosphere; between 22 km and the tropopause MIPAS temperatures were found to be biased low by up to 2 K, while below the tropopause, they were found to be too high by the same amount. These findings confirm earlier comparisons of MIPAS temperatures to ECMWF data which revealed similar differences. Above 12 km up to 45 km, MIPAS water vapor (version V4O H2O 203) is well within 10 % of the data of all correlative instruments. The well-known dry bias of MIPAS water vapor above 50 km due to neglect of non-LTE effects in the current retrievals has been confirmed. Some instruments indicate that MIPAS water vapor might be biased high by 20 to 40 % around 10 km (or 5 km below the tropopause), but a consistent picture from all comparisons could not be derived. MIPAS ozone (version V4O O3 202) has a high bias of up to +0.9 ppmv around 37 km which is due to a non-identified continuum like radiance contribution. No further significant biases have been detected. Cross-comparison to co-located observations of other satellite instruments (Aura/MLS, ACE-FTS, AIRS) is provided as well.

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“…Nedoluha et al, 1999;Forkman et al, 2003;Deuber et al, 2004;De Wachter et al, 2011;Straub et al, 2010). showed, that it is also possible to use measurements of such radiometers to additionally retrieve tropospheric water vapour profiles, reinforced by simulated retrievals and retrievals with real data of the MIAWARA radiometer, operated by the Institute of Applied Physics, University of Bern.…”

Section: Introductionmentioning

confidence: 99%

Retrieval of tropospheric water vapour by using spectra of a 22 GHz radiometer

2011

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Abstract. In this paper, we present an approach to retrieve tropospheric water vapour profiles from pressure broadened emission spectra at 22 GHz, measured by a ground based microwave radiometer installed in the south of Bern at 905 m.Classical microwave instruments concentrating on the troposphere observe several channels in the center and the wings of the water vapour line (20-30 Ghz), whereas our retrieval approach uses spectra with a bandwidth of 1 GHz and a high resolution around the center of the 22 GHz water vapour line.The retrieval is sensitive up to 7 km with a vertical resolution of 3-5 km. Comparisons with profiles from operational balloon soundings, performed at Payerne, 40 km away from the radiometer location, showed a good agreement up to 7 km with a correlation of above 0.8. The retrievals shows a wet bias of 10-20 % compared to the sounding.

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MIAWARA-C, a new ground based water vapor radiometer for measurement campaigns

Cited by 48 publications

References 28 publications

Ozone profiles above Kiruna from two ground-based radiometers

Ozone profiles above Kiruna from two ground-based radiometers

Validation of MIPAS IMK/IAA temperature, water vapor, and ozone profiles with MOHAVE-2009 campaign measurements

Retrieval of tropospheric water vapour by using spectra of a 22 GHz radiometer

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