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

Bleisch, René; Kämpfer, Niklaus; Haefele, Alexander

doi:10.5194/amt-4-1891-2011

Cited by 29 publications

(23 citation statements)

References 33 publications

(29 reference statements)

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“…A tropospheric water vapour profile is also included in the forward model. The profile is obtained from the measured surface water vapour density at the ground (from a weather station), assuming a exponential decrease of the water vapour with altitude and a scale height of 2 km (Bleisch et al, 2011). Standard atmospheric profiles for summer and winter are considered for other species such as oxygen and nitrogen (Anderson et al, 1986); these profiles are incorporated into ARTS2.…”

Section: Methodsmentioning

confidence: 99%

Validation of brightness and physical temperature from two scanning microwave radiometers in the 60 GHz O<sub>2</sub> band using radiosonde measurements

2016

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Abstract. In this paper, we address the assessment of the tropospheric performance of a new temperature radiometer (TEMPERA) at 60 GHz. With this goal, an intercomparison campaign was carried out at the aerological station of MeteoSwiss in Payerne (Switzerland). The brightness temperature and the tropospheric temperature were assessed by means of a comparison with simultaneous and collocated radiosondes that are launched twice a day at this station. In addition, the TEMPERA performances are compared with the ones from a commercial microwave radiometer (HAT-PRO), which has some different instrumental characteristics and uses a different inversion algorithm. Brightness temperatures from both radiometers were compared with the ones simulated using a radiative transfer model and atmospheric profiles from radiosondes. A total of 532 cases were analyzed under all weather conditions and evidenced larger brightness temperature deviations between the two radiometers and the radiosondes for the most transparent channels. Two different retrievals for the TEMPERA radiometer were implemented in order to evaluate the effect of the different channels on the temperature retrievals. The comparison with radiosondes evidenced better results very similar to the ones from HATPRO, when the eight more opaque channels were used. The study shows the good performance of TEMPERA to retrieve temperature profiles in the troposphere. The inversion method of TEMPERA is based on the optimal estimation method. The main advantage of this algorithm is that there is no necessity for radiosonde information to achieve good results in contrast to conventional methods as neural networks or lineal regression. Finally, an assessment of the effect of instrumental characteristics as the filter response and the antenna pattern on the brightness temperature showed that they can have an important impact on the most transparent channels.

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Section: Methodsmentioning

confidence: 99%

Validation of brightness and physical temperature from two scanning microwave radiometers in the 60 GHz O<sub>2</sub> band using radiosonde measurements

2016

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“…In the forward model a water-vapor profile with an exponential decrease is included. This profile is calculated with the measured surface water vapor density from the ExWiWeather station (placed next to TEMPERA) and assuming a scale height of 2000 m. Further descriptions can be found in Bleisch et al (2011). For other species like oxygen (O 2 ) and nitrogen (N 2 ) we used standard atmospheric profiles for summer and winter, which are incorporated into ARTS2 (middle latitude FASCODE (Fast Atmospheric Signature CODE) (Anderson et al, 1986)).…”

Section: Forward Model Parametersmentioning

confidence: 99%

Microwave radiometer to retrieve temperature profiles from the surface to the stratopause

et al. 2013

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Abstract. TEMPERA (TEMPERature RAdiometer) is a new ground-based radiometer which measures in a frequency range from 51-57 GHz radiation emitted by the atmosphere. With this instrument it is possible to measure temperature profiles from ground to about 50 km. This is the first groundbased instrument with the capability to retrieve temperature profiles simultaneously for the troposphere and stratosphere. The measurement is done with a filterbank in combination with a digital fast Fourier transform spectrometer. A hot load and a noise diode are used as stable calibration sources. The optics consist of an off-axis parabolic mirror to collect the sky radiation. Due to the Zeeman effect on the emission lines used, the maximum height for the temperature retrieval is about 50 km. The effect is apparent in the measured spectra. The performance of TEMPERA is validated by comparison with nearby radiosonde and satellite data from the Microwave Limb Sounder on the Aura satellite. In this paper we present the design and measurement method of the instrument followed by a description of the retrieval method, together with a validation of TEMPERA data over its first year, 2012.

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“…A tropospheric water vapour profile with an exponential decrease is included. This profile is calculated with the measured surface water vapour density from the ExWi weather station (placed next to TEMPERA) and assuming a scale height of 2000 m (Bleisch et al, 2011). For other species like oxygen (O 2 ) and nitrogen (N 2 ) we used standard atmospheric profiles for summer and winter (Anderson et al, 1986), which are incorporated into ARTS2.…”

Section: Retrievalmentioning

confidence: 99%

An integrated approach toward the incorporation of clouds in the temperature retrievals from microwave measurements

2014

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Abstract. In this paper, we address the characterization of clouds and its inclusion in microwave retrievals in order to study its effect on tropospheric temperature profiles measured by TEMPERA radiometer. TEMPERA is the first ground-based microwave radiometer that makes it possible to obtain temperature profiles in the troposphere and stratosphere at the same time. In order to characterize the clouds a multi-instrumental approach has been adopted. Cloud base altitudes were detected using ceilometer measurements while the integrated liquid water was measured by TROWARA radiometer. Both instruments are co-located with TEMPERA in Bern (Switzerland). Using this information and a constant Liquid Water Content value inside the cloud a liquid profile is provided to characterize the clouds in the inversion algorithm. Microwave temperature profiles have been obtained incorporating this water liquid profile in the inversion algorithm and also without considering the clouds, in order to assess its effect on the retrievals. The results have been compared with the temperature profiles from radiosondes which are launched twice a day at the aerological station of MeteoSwiss in Payerne (40 km W of Bern). Almost 1 year of data have been analysed and 60 non-precipitating cloud cases were studied. The statistical analysis carried out over all the cases evidenced that temperature retrievals improved in most of the cases when clouds were incorporated in the inversion algorithm.

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

Cited by 29 publications

References 33 publications

Validation of brightness and physical temperature from two scanning microwave radiometers in the 60 GHz O<sub>2</sub> band using radiosonde measurements

Validation of brightness and physical temperature from two scanning microwave radiometers in the 60 GHz O<sub>2</sub> band using radiosonde measurements

Microwave radiometer to retrieve temperature profiles from the surface to the stratopause

An integrated approach toward the incorporation of clouds in the temperature retrievals from microwave measurements

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

Cited by 29 publications

References 33 publications

Validation of brightness and physical temperature from two scanning microwave radiometers in the 60 GHz O&lt;sub&gt;2&lt;/sub&gt; band using radiosonde measurements

Validation of brightness and physical temperature from two scanning microwave radiometers in the 60 GHz O&lt;sub&gt;2&lt;/sub&gt; band using radiosonde measurements

Microwave radiometer to retrieve temperature profiles from the surface to the stratopause

An integrated approach toward the incorporation of clouds in the temperature retrievals from microwave measurements

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Product

Resources

About

Validation of brightness and physical temperature from two scanning microwave radiometers in the 60 GHz O<sub>2</sub> band using radiosonde measurements

Validation of brightness and physical temperature from two scanning microwave radiometers in the 60 GHz O<sub>2</sub> band using radiosonde measurements