scholarly journals Quantifying Marine Boundary Layer Water Vapor beneath Low Clouds with Near-Infrared and Microwave Imagery

2016 ◽  
Vol 55 (1) ◽  
pp. 213-225 ◽  
Author(s):  
Luis Millán ◽  
M. Lebsock ◽  
E. Fishbein ◽  
P. Kalmus ◽  
J. Teixeira
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Near Infrared ◽  
Marine Boundary Layer ◽  
Reanalysis Data ◽  
Microwave Radiometry ◽  
Infrared Imagery ◽  
The Difference ◽  
Simple Equations ◽  
Cloud Top Pressure

AbstractThis study investigates the synergy of collocated microwave radiometry and near-infrared imagery to estimate the marine boundary layer water vapor beneath uniform cloud fields. Microwave radiometry provides the total column water vapor, while the near-infrared imagery provides the water vapor above the cloud layers. The difference between the two gives the vapor between the surface and the cloud top, which may be interpreted as the boundary layer water vapor. In combining the two datasets, we apply several flags as well as proximity tests to remove pixels with high clouds and/or intrapixel heterogeneity. Comparisons against radiosonde and ECMWF reanalysis data demonstrate the robustness of these boundary layer water vapor estimates. Last, it is shown that the measured AMSR-MODIS boundary layer water vapor can be analyzed using sea surface temperature and cloud-top pressure information by employing simple equations based on the Clausius–Clapeyron relationship.

scholarly journals Variability of Bulk Water Vapor Content in the Marine Cloudy Boundary Layers from Microwave and Near-Infrared Imagery

2019 ◽  
Author(s):  
Luis F. Millán ◽  
Matthew D. Lebsock ◽  
Joao Teixeira
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Near Infrared ◽  
Cloud Amount ◽  
Bulk Water ◽  
Sea Surface ◽  
Infrared Imagery ◽  
Total Column

Abstract. This work uses the synergy of collocated microwave radiometry and near-infrared imagery to study the marine boundary layer water vapor. The Advanced Microwave Scanning Radiometer (AMSR) provides the total column water vapor, while the Moderate Resolution Imaging Spectroradiometer (MODIS) near-infrared imagery provides the water vapor above the cloud layers. The difference between the two gives the vapor between the surface and the cloud top, which may be interpreted as the boundary layer water vapor under certain conditions. As a by product of this algorithm, we also store cloud top information of the MODIS pixels used, a proxy for the inversion height, as well as the sea surface temperature and total column water vapor from the AMSR measurements. Hence, the AMSR-MODIS dataset provides several of the variables associated with the boundary layer thermodynamic structure. Comparisons against radiosondes, and GPS-Radio Occultation data demonstrate the robustness of these boundary layer water vapor estimates. We explore the annual cycle of the number of observations as a proxy for stratus cloud amount, in well known stratus regions; we then exploit the 16 years of AMSR-MODIS synergy to study for the first time the annual variations of the boundary layer water vapor in comparison to the sea surface temperature and the boundary layer cloud top height (equivalent to the inversion height) climatologies, and lastly, we explore the climatological behavior of these variables on stratocumulus-to-cumulus transitions.

scholarly journals Variability of bulk water vapor content in the marine cloudy boundary layers from microwave and near-infrared imagery

2019 ◽  
Vol 19 (13) ◽  
pp. 8491-8502
Author(s):  
Luis F. Millán ◽  
Matthew D. Lebsock ◽  
Joao Teixeira
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Near Infrared ◽  
Cloud Amount ◽  
Bulk Water ◽  
Sea Surface ◽  
Infrared Imagery ◽  
Total Column

Abstract. This work uses the synergy of collocated microwave radiometry and near-infrared imagery to study the marine boundary layer water vapor. The Advanced Microwave Scanning Radiometer (AMSR) provides the total column water vapor, while the Moderate Resolution Imaging Spectroradiometer (MODIS) near-infrared imagery provides the water vapor above the cloud layers. The difference between the two gives the vapor between the surface and the cloud top, which may be interpreted as the boundary layer water vapor under certain conditions. As a by-product of this algorithm, we also store cloud top information of the MODIS pixels used, a proxy for the inversion height, as well as the sea surface temperature and total column water vapor from the AMSR measurements. Hence, the AMSR–MODIS dataset provides several of the variables associated with the boundary layer thermodynamic structure. Comparisons against radiosondes and GPS radio occultation (GPSRO) data demonstrate the robustness of these boundary layer water vapor estimates. We explore the annual cycle of the number of observations as a proxy for stratus cloud amount, in well-known stratus regions; we then exploit the 16 years of AMSR–MODIS synergy to study for the first time the annual variations of the boundary layer water vapor in comparison to the sea surface temperature and the boundary layer cloud top height (equivalent to the inversion height) climatologies, and lastly we explore the climatological behavior of these variables on stratocumulus-to-cumulus transitions.

Why sometimes its simply sunny (in the trades)

2021 ◽  
Author(s):  
Bjorn Stevens ◽  
Ilya Serikov ◽  
Anna Lea Albright ◽  
Sandrine Bony ◽  
Geet George ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Marine Boundary Layer ◽  
Cloud Base ◽  
Lidar Signal ◽  
Cloud Base Height

<p>Cloud free skies are rare in the trades.  We analyze conditions in which cloud-free conditions prevail.  For this purpose Raman water vapor measurements from the Barbados Cloud Observatory, complemented by ship-based measurements during EUREC4A are used to explore water vapor variability in the marine boundary layer.   We explore the consistency of the inferred cloud base height with estimates of temperature and water vapor from the lidar signal, and examine the co-variability of these quantities.  After having established the properties of these measurements, we seek to use them as well as others, to explain in what ways periods of cloud-free conditions are maintained, investigating the hypothesis that only when the wind stills is it simply sunny.</p>

scholarly journals A Framework to Study Mixing Processes in the Marine Boundary Layer Using Water Vapor Isotope Measurements

2018 ◽  
Vol 45 (5) ◽  
pp. 2524-2532 ◽  
Author(s):  
M. Benetti ◽  
J.‐L. Lacour ◽  
A. E. Sveinbjörnsdóttir ◽  
G. Aloisi ◽  
G. Reverdin ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Marine Boundary Layer ◽  
Mixing Processes ◽  
Isotope Measurements

scholarly journals Mission Configuration and Retrieval Technique for Profiling Water Vapor in the Marine Boundary Layer

2021 ◽  
Author(s):  
Stephen Leroy ◽  
Igor Polonsky ◽  
Alexandra Meredith ◽  
Kerri Cahoy ◽  
Lucy Halperin ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Marine Boundary Layer ◽  
Retrieval Technique

scholarly journals Missing OH reactivity in the global marine boundary layer

2020 ◽  
Vol 20 (6) ◽  
pp. 4013-4029 ◽  
Author(s):  
Alexander B. Thames ◽  
William H. Brune ◽  
David O. Miller ◽  
Hannah M. Allen ◽  
Eric C. Apel ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Dimethyl Sulfide ◽  
Marine Boundary Layer ◽  
Limit Of Detection ◽  
Chemical Species ◽  
Volatile Organic ◽  
The Mean ◽  
The Difference

Abstract. The hydroxyl radical (OH) reacts with thousands of chemical species in the atmosphere, initiating their removal and the chemical reaction sequences that produce ozone, secondary aerosols, and gas-phase acids. OH reactivity, which is the inverse of OH lifetime, influences the OH abundance and the ability of OH to cleanse the atmosphere. The NASA Atmospheric Tomography (ATom) campaign used instruments on the NASA DC-8 aircraft to measure OH reactivity and more than 100 trace chemical species. ATom presented a unique opportunity to test the completeness of the OH reactivity calculated from the chemical species measurements by comparing it to the measured OH reactivity over two oceans across four seasons. Although the calculated OH reactivity was below the limit of detection for the ATom instrument used to measure OH reactivity throughout much of the free troposphere, the instrument was able to measure the OH reactivity in and just above the marine boundary layer. The mean measured value of OH reactivity in the marine boundary layer across all latitudes and all ATom deployments was 1.9 s−1, which is 0.5 s−1 larger than the mean calculated OH reactivity. The missing OH reactivity, the difference between the measured and calculated OH reactivity, varied between 0 and 3.5 s−1, with the highest values over the Northern Hemisphere Pacific Ocean. Correlations of missing OH reactivity with formaldehyde, dimethyl sulfide, butanal, and sea surface temperature suggest the presence of unmeasured or unknown volatile organic compounds or oxygenated volatile organic compounds associated with ocean emissions.

A Multi-Wavelength Mini Lidar for Measurements of Marine Boundary Layer Aerosol and Water Vapor Fields

2001 ◽  
Author(s):  
Shiv K. Sharma ◽  
Barry R. Lienert ◽  
John N. Porter ◽  
Antony D. Clarke
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Marine Boundary Layer ◽  
Multi Wavelength
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