The Seoul Water Vapor Radiometer for the Middle Atmosphere: Calibration, Retrieval, and Validation

Wachter, E. De; Haefele, Alexander; Kämpfer, Niklaus; Ka, Soohyun; Lee, Jung Eun; Oh, Jung Jin

doi:10.1109/tgrs.2010.2072932

Cited by 21 publications

(12 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Water vapor is retrieved for altitudes between approximately 45 and 75 km (De Wachter et al, 2011). The lower observation limit is relatively high because strong baseline ripples in the measured spectrum do not allow a retrieval of the line wings, which contain information for altitudes below 45 km.…”

Section: Datamentioning

confidence: 99%

The quasi 16-day wave in mesospheric water vapor during boreal winter 2011/2012

et al. 2014

View full text Add to dashboard Cite

Abstract. This study investigates the characteristics of the quasi 16-day wave in the mesosphere during boreal winter 2011/2012 using observations of water vapor from groundbased microwave radiometers and satellite data. The groundbased microwave radiometers are located in Seoul (South Korea, 37 • N), Bern (Switzerland, 47 • N) and Sodankylä (Finland, 67 • N). The quasi 16-day wave is observed in the mesosphere at all three locations, while the dominant period increases with latitude from 15 days at Seoul to 20 days at Sodankylä. The observed evolution of the quasi 16-day wave confirms that the wave activity is strongly decreased during a sudden stratospheric warming that occurred in midJanuary 2012. Using satellite data from the Microwave Limb Sounder on the Aura satellite, we examine the zonal characteristics of the quasi 16-day wave and conclude that the observed waves above the midlatitudinal stations Seoul and Bern are eastward-propagating s = −1 planetary waves with periods of 15 to 16 days, while the observed oscillation above the polar station Sodankylä is a standing wave with a period of approximately 20 days. The strongest relative wave amplitudes in water vapor during the investigated time period are approximately 15 %. The wave activity varies strongly along a latitude circle. The activity of the quasi 16-day wave in mesospheric water vapor during boreal winter 2011/2012 is strongest over northern Europe, the North Atlantic Ocean and northwestern Canada. The region of highest wave activity seems to be related to the position of the polar vortex. We conclude that the classic approach to characterize planetary waves zonally averaged along a latitude circle is not sufficient to explain the local observations because of the strong longitudinal dependence of the wave activity.

show abstract

Section: Datamentioning

confidence: 99%

The quasi 16-day wave in mesospheric water vapor during boreal winter 2011/2012

et al. 2014

View full text Add to dashboard Cite

show abstract

“…The atmospheric temperature is perturbed by ±5 K, which is the upper limit of the 1-sigma variability of the 20-year SD-WACCM temperature climatology above Troll. For the estimation of the calibration error we take into account the uncertainties in the hot/cold load calibration, standing waves, line of sight and tropospheric correction factor, and find that it is equivalent to, at most, a 10 % variation of the tropospheric correction factor (Jarchow and Hartogh, 1994;De Wachter et al, 2011;Straub et al, 2013). Thus the total calibration error, including the uncertainty in the tropospheric correction, is taken to be 10 % of the tropospheric correction factor.…”

Section: Error Characterizationmentioning

confidence: 99%

Atmospheric ozone above Troll station, Antarctica observed by a ground based microwave radiometer

Daae

Straub

Espy

et al. 2014

Earth Syst. Sci. Data

View full text Add to dashboard Cite

Abstract. This paper describes the stratospheric and mesospheric ozone profiles retrieved from spectral measurements of the 249.96 GHz O 3 line, using the British Antarctic Survey's ground-based Microwave Radiometer at Troll (BAS-MRT), Antarctica (72• 01 S, 02• 32 E, 62• Mlat). The instrument operated at Troll from February 2008 through January 2010, and hourly averaged spectra were used to retrieve approximately 20 ozone profiles per day. The ozone profiles cover the pressure range from 3 hPa to 0.02 hPa (approximately 38 to 72 km) which includes the topside of the stratospheric ozone layer and the peak of the tertiary maximum. Comparing the retrieved ozone volume mixing ratio (vmr) values to Aura/MLS and SD-WACCM shows no significant bias to within the instrumental uncertainties. The long-term variations (> 20 days) between MLS and SD-WACCM agree well with BAS-MRT at all altitudes with significant correlation coefficients of at least 0.9 (0.7 with SD-WACCM) in the upper stratosphere and middle mesosphere. A weaker correlation is found for the long-term variations in summer when most of the vmr values are below the random noise level of Aura/MLS. The correlation of short-term variations (< 20 days) between MLS and BAS-MRT agree well at all altitudes with significant correlation coefficients of at least 0.7 in the upper stratosphere and middle mesosphere. The ozone profiles retrieved at Troll, Antarctica extend the sparse data coverage of middle atmospheric ozone above Antarctica, where, due to the dynamic nature of the ozone concentrations, systematic observations with a high temporal resolution are desirable. The O 3 profiles presented here are stored at the UK's Polar Data Centre (http://doi.org/nc3) and are available for public scientific use.

show abstract

“…Thorough discussions of the error characterisation for 22 GHz radiometers are presented in De Wachter et al (2011). A posteriori covariance matrices are calculated for different families of uncertainty, namely measurement noise, calibration, spectroscopic parameters and temperatures used in the forward model.…”

Section: Error Characterisationmentioning

confidence: 99%

Validation of middle-atmospheric campaign-based water vapour measured by the ground-based microwave radiometer MIAWARA-C

et al. 2013

View full text Add to dashboard Cite

Abstract. Middle atmospheric water vapour can be used as a tracer for dynamical processes. It is mainly measured by satellite instruments and ground-based microwave radiometers. Ground-based instruments capable of measuring middle-atmospheric water vapour are sparse but valuable as they complement satellite measurements, are relatively easy to maintain and have a long lifetime. MIAWARA-C is a ground-based microwave radiometer for middle-atmospheric water vapour designed for use on measurement campaigns for both atmospheric case studies and instrument intercomparisons. MIAWARA-C's retrieval version 1.1 (v1.1) is set up in a such way as to provide a consistent data set even if the instrument is operated from different locations on a campaign basis. The sensitive altitude range for v1.1 extends from 4 hPa (37 km) to 0.017 hPa (75 km). For v1.1 the estimated systematic error is approximately 10% for all altitudes. At lower altitudes it is dominated by uncertainties in the calibration, with altitude the influence of spectroscopic and temperature uncertainties increases. The estimated random error increases with altitude from 5 to 25%. MIAWARA-C measures two polarisations of the incident radiation in separate receiver channels, and can therefore provide two measurements of the same air mass with independent instrumental noise. The standard deviation of the difference between the profiles obtained from the two polarisations is in excellent agreement with the estimated random measurement error of v1.1. In this paper, the quality of v1.1 data is assessed for measurements obtained at two different locations: (1) a total of 25 months of measurements in the Arctic (Sodankylä, 67.37° N, 26.63° E) and (2) nine months of measurements at mid-latitudes (Zimmerwald, 46.88° N, 7.46° E). For both locations MIAWARA-C's profiles are compared to measurements from the satellite experiments Aura MLS and MIPAS. In addition, comparisons to ACE-FTS and SOFIE are presented for the Arctic and to the ground-based radiometer MIAWARA for the mid-latitude campaigns. In general, all intercomparisons show high correlation coefficients, confirming the ability of MIAWARA-C to monitor temporal variations of the order of days. The biases are generally below 13% and within the estimated systematic uncertainty of MIAWARA-C. No consistent wet or dry bias is identified for MIAWARA-C. In addition, comparisons to the reference instruments indicate the estimated random error of v1.1 to be a realistic measure of the random variation on the retrieved profile between 45 and 70 km.

show abstract

The Seoul Water Vapor Radiometer for the Middle Atmosphere: Calibration, Retrieval, and Validation

Cited by 21 publications

References 17 publications

The quasi 16-day wave in mesospheric water vapor during boreal winter 2011/2012

The quasi 16-day wave in mesospheric water vapor during boreal winter 2011/2012

Atmospheric ozone above Troll station, Antarctica observed by a ground based microwave radiometer

Validation of middle-atmospheric campaign-based water vapour measured by the ground-based microwave radiometer MIAWARA-C

Contact Info

Product

Resources

About