Calibration of Meteosat water vapor channel observations with independent satellite observations

2001 ◽  
Vol 106 (D6) ◽  
pp. 5199-5209 ◽  
Author(s):  
Stephen A. Tjemkes ◽  
Marianne König ◽  
Hans-Joachim Lutz ◽  
Leo van de Berg ◽  
Johannes Schmetz
Keyword(s):  
Water Vapor ◽  
Satellite Observations ◽  
Vapor Channel

scholarly journals Effect of tropical cyclones on the Stratosphere-Troposphere Exchange observed using satellite observations over north Indian Ocean

2016 ◽  
Author(s):  
M. Venkat Ratnam ◽  
S. Ravindra Babu ◽  
S. S. Das ◽  
Ghouse Basha ◽  
B. V. Krishnamurthy ◽  
...  
Keyword(s):  
Water Vapor ◽  
Indian Ocean ◽  
Tropical Cyclones ◽  
Lower Stratosphere ◽  
North Indian Ocean ◽  
Satellite Observations ◽  
Upper Troposphere ◽  
North West ◽  
The North ◽  
The Impact

Abstract. Tropical cyclones play an important role in modifying the tropopause structure and dynamics as well as stratosphere-troposphere exchange (STE) process in the Upper Troposphere and Lower Stratosphere (UTLS) region. In the present study, the impact of cyclones that occurred over the North Indian Ocean during 2007–2013 on the STE process is quantified using satellite observations. Tropopause characteristics during cyclones are obtained from the Global Positioning System (GPS) Radio Occultation (RO) measurements and ozone and water vapor concentrations in UTLS region are obtained from Aura-Microwave Limb Sounder (MLS) satellite observations. The effect of cyclones on the tropopause parameters is observed to be more prominent within 500 km from the centre of cyclone. In our earlier study we have observed decrease (increase) in the tropopause altitude (temperature) up to 0.6 km (3 K) and the convective outflow level increased up to 2 km. This change leads to a total increase in the tropical tropopause layer (TTL) thickness of 3 km within the 500 km from the centre of cyclone. Interestingly, an enhancement in the ozone mixing ratio in the upper troposphere is clearly noticed within 500 km from cyclone centre whereas the enhancement in the water vapor in the lower stratosphere is more significant on south-east side extending from 500–1000 km away from the cyclone centre. We estimated the cross-tropopause mass flux for different intensities of cyclones and found that the mean flux from stratosphere to troposphere for cyclonic stroms is 0.05 ± 0.29 × 10−3 kg m−2 and for very severe cyclonic stroms it is 0.5 ± 1.07 × 10−3 kg m−2. More downward flux is noticed in the north-west and south-west side of the cyclone centre. These results indicate that the cyclones have significant impact in effecting the tropopause structure, ozone and water vapour budget and consequentially the STE in the UTLS region.

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

Atmosphere ◽  
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.

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

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.

scholarly journals Intercalibrating Microwave Satellite Observations for Monitoring Long-Term Variations in Upper- and Midtropospheric Water Vapor*

2013 ◽  
Vol 30 (10) ◽  
pp. 2303-2319 ◽  
Author(s):  
Eui-Seok Chung ◽  
Brian J. Soden ◽  
Viju O. John
Keyword(s):  
Water Vapor ◽  
Relative Humidity ◽  
Sampling Bias ◽  
Quantitative Agreement ◽  
Observation Time ◽  
Satellite Observations ◽  
Water Vapor Absorption ◽  
Infrared Measurements ◽  
Orbital Drift

Abstract This paper analyzes the growing archive of 183-GHz water vapor absorption band measurements from the Advanced Microwave Sounding Unit B (AMSU-B) and Microwave Humidity Sounder (MHS) on board polar-orbiting satellites and document adjustments necessary to use the data for long-term climate monitoring. The water vapor channels located at 183.31 ± 1 GHz and 183.31 ± 3 GHz are sensitive to upper- and midtropospheric relative humidity and less prone to the clear-sky sampling bias than infrared measurements, making them a valuable but underutilized source of information on free-tropospheric water vapor. A method for the limb correction of the satellite viewing angle based upon a simplified model of radiative transfer is introduced to remove the scan angle dependence of the radiances. Biases due to the difference in local observation time between satellites and spurious trends associated with satellite orbital drift are then diagnosed and adjusted for using synthetic radiative simulations based on the Interim European Centre for Medium-Range Weather Forecasts Re-Analysis (ERA-Interim). The adjusted, cloud-filtered, and limb-corrected brightness temperatures are then intercalibrated using zonal-mean brightness temperature differences. It is found that these correction procedures significantly improve consistency and quantitative agreement between microwave radiometric satellite observations that can be used to monitor upper- and midtropospheric water vapor. The resulting radiances are converted to estimates of the deep-layer-mean upper- and midtropospheric relative humidity, and can be used to evaluate trends in upper-tropospheric relative humidity from reanalysis datasets and coupled ocean–atmosphere models.

scholarly journals First UV satellite observations of mesospheric water vapor

2008 ◽  
Vol 113 (D12) ◽  
Author(s):  
Michael H. Stevens ◽  
R. L. Gattinger ◽  
J. Gumbel ◽  
E. J. Llewellyn ◽  
D. A. Degenstein ◽  
...  
Keyword(s):  
Water Vapor ◽  
Satellite Observations
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