Comments on “Information Content of METEOSAT and Nimbus/THIR Water Vapor Channel Data: Altitude Association of Observed Phenomena”

Abstract. Thermodynamic profiles in the planetary boundary layer (PBL) are important observations for a range of atmospheric research and operational needs. These profiles can be retrieved from passively sensed spectral infrared (IR) or microwave (MW) radiance observations or can be more directly measured by active remote sensors such as water vapor differential absorption lidars (DIALs). This paper explores the synergy of combining ground-based IR, MW, and DIAL observations using an optimal-estimation retrieval framework, quantifying the reduction in the uncertainty in the retrieved profiles and the increase in information content as additional observations are added to IR-only and MW-only retrievals. This study uses ground-based observations collected during the Perdigão field campaign in central Portugal in 2017 and during the DIAL demonstration campaign at the Atmospheric Radiation Measurement Southern Great Plains site in 2017. The results show that the information content in both temperature and water vapor is higher for the IR instrument relative to the MW instrument (thereby resulting in smaller uncertainties) and that the combined IR + MW retrieval is very similar to the IR-only retrieval below 1.5 km. However, including the partial profile of water vapor observed by the DIAL increases the information content in the combined IR + DIAL and MW + DIAL water vapor retrievals substantially, with the exact impact vertically depending on the characteristics of the DIAL instrument itself. Furthermore, there is a slight increase in the information content in the retrieved temperature profile using the IR + DIAL relative to the IR-only; this was not observed in the MW + DIAL retrieval.

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Relationships between Low-Level Jet and Low Visibility Associated with Precipitation, Air Pollution, and Fog in Tianjin

Atmosphere ◽

10.3390/atmos11111197 ◽

2020 ◽

Vol 11 (11) ◽

pp. 1197

Author(s):

Tingting Ju ◽

Bingui Wu ◽

Zhaoyu Wang ◽

Jingle Liu ◽

Dehua Chen ◽

...

Keyword(s):

Air Pollution ◽

Water Vapor ◽

Air Masses ◽

Low Level ◽

Vapor Channel ◽

Low Visibility ◽

Low Level Jet ◽

Industrial Regions ◽

Statistical Results ◽

Pm2.5 Concentration

In this study, relationships between low-level jet (LLJ) and low visibility associated with precipitation, air pollution, and fog in Tianjin are investigated based on observational data from January to December, 2016. Statistical results show 55% of precipitation is accompanied by LLJ, and two causes responsible for the relatively high percentage are presented. The result of case analysis shows that some southwesterly LLJs are favorable for the formation of precipitation by transporting water vapor when the water vapor channel from the South China Sea or Bengal Bay to Bohai Rim region is established. Statistical results show 55% of pollution episodes (PEs) are accompanied by LLJs. When pollutions are observed in the southern industrial regions, nocturnal southwesterly LLJ, which can carry polluted air masses from polluted regions to Tianjin and induce turbulent mixing, can enhance surface PM2.5 concentration and is favorable for the formation of surface pollution at night. Nocturnal northerly or southeasterly LLJ leads to clear air masses mixing with polluted air masses and is favorable for increasing visibility. Contributions of southwesterly LLJs to the formation of fog and precipitation are similar, which both rely on establishing the water vapor channel despite occurrence heights of LLJs being different.

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Diffuse sunlight based calibration of the water vapor channel in the upc raman lidar

EPJ Web of Conferences ◽

10.1051/epjconf/201817605035 ◽

2018 ◽

Vol 176 ◽

pp. 05035

Author(s):

Constantino Muñoz-Porcar ◽

Adolfo Comeron ◽

Michaël Sicard ◽

Ruben Barragan ◽

David Garcia-Vizcaino ◽

...

Keyword(s):

Water Vapor ◽

Raman Scattering ◽

Calibration Factor ◽

Raman Lidar ◽

Lidar System ◽

System Parameters ◽

Vapor Channel ◽

Technical University

A method for determining the calibration factor of the water vapor channel of a Raman lidar, based on zenith measurements of diffuse sunlight and on assumptions regarding some system parameters and Raman scattering models, has been applied to the lidar system of Universitat Politècnica de Catalunya (UPC; Technical University of Catalonia, Spain). Results will be analyzed in terms of stability and comparison with typical methods relying on simultaneous radiosonde measurements.

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Evaluation of the distribution of subtropical free tropospheric humidity in AMIP-2 simulations using METEOSAT water vapor channel data

Geophysical Research Letters ◽

10.1029/2005gl024341 ◽

2005 ◽

Vol 32 (19) ◽

pp. n/a-n/a ◽

Cited By ~ 20

Author(s):

H. Brogniez ◽

R. Roca ◽

L. Picon

Keyword(s):

Water Vapor ◽

Vapor Channel

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Radiometric Information Content for Water Vapor and Temperature Profiling in Clear Skies Between 10 and 200 GHz

IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing ◽

10.1109/jstars.2014.2364394 ◽

2015 ◽

Vol 8 (2) ◽

pp. 859-871 ◽

Cited By ~ 6

Author(s):

Swaroop Sahoo ◽

Xavier Bosch-Lluis ◽

Steven C. Reising ◽

Jothiram Vivekanandan

Keyword(s):

Water Vapor ◽

Information Content

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Upper tropospheric humidity and wind fields observed with the METEOSAT water vapor channel

10.1117/12.196685 ◽

1994 ◽

Author(s):

Leopold Van de Berg ◽

John Whitlock ◽

Carlos Geijo ◽

Johannes Schmetz

Keyword(s):

Water Vapor ◽

Wind Fields ◽

Vapor Channel ◽

Upper Tropospheric Humidity

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Ground-based Temperature and Humidity Profiling: Combining Active and Passive Remote Sensors

10.5194/amt-2020-352 ◽

2020 ◽

Author(s):

David D. Turner ◽

Ulrich Löhnert

Keyword(s):

Water Vapor ◽

Information Content ◽

Great Plains ◽

Optimal Estimation ◽

Differential Absorption ◽

Southern Great Plains ◽

Atmospheric Research ◽

Remote Sensors ◽

Central Portugal ◽

Atmospheric Radiation Measurement

Abstract. Thermodynamic profiles in the planetary boundary layer (PBL) are important observations for a range of atmospheric research and operational needs. These profiles can be retrieved from passively sensed spectral infrared (IR) or microwave (MW) radiance observations, or can be more directly measured by active remote sensors such as water vapor differential absorption lidars (DIALs). This paper explores the synergy of combining ground-based IR, MW, and DIAL observations using an optimal estimation retrieval framework, quantifying the reduction in the uncertainty in the retrieved profiles and the increase in information content as additional observations are added to IR-only and MW-only retrievals. This study uses ground-based observations collected during the Perdigao field campaign in central Portugal in 2017 and during the DIAL demonstration campaign at the Atmospheric Radiation Measurement Southern Great Plains site in 2017. The results show that the information content in both temperature and water vapor is higher for IR instrument relative to the MW instrument (thereby resulting in smaller uncertainties), and that the combined IR+MW retrieval is very similar to the IR-only retrieval below 1.5 km. However, including the partial profile of water vapor observed by the DIAL increases the information content in the combined IR+DIAL and MW+DIAL water vapor retrievals substantially, with the exact impact vertically depending on the characteristics of the DIAL instrument itself. Furthermore, there is slight increase in the information content in the retrieved temperature profile using the IR+DIAL relative to the IR-only; this was not observed in the MW+DIAL retrieval.

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