Estimation of Vertical Distributions of Water Vapor from Spaceborne Observations of Scattered Sunlight

2001 ◽  
Author(s):  
Dale P. Winebrenner ◽  
John Sylvester
Keyword(s):  
Water Vapor ◽  
Vertical Distributions

scholarly journals Retrieval of water vapor vertical distributions in the upper troposphere and the lower stratosphere from SCIAMACHY limb measurements

2011 ◽  
Vol 4 (5) ◽  
pp. 933-954 ◽  
Author(s):  
A. Rozanov ◽  
K. Weigel ◽  
H. Bovensmann ◽  
S. Dhomse ◽  
K.-U. Eichmann ◽  
...  
Keyword(s):  
Water Vapor ◽  
Solar Radiation ◽  
Lower Stratosphere ◽  
Water Vapor Content ◽  
Retrieval Algorithm ◽  
Altitude Range ◽  
Upper Troposphere ◽  
Vertical Distributions ◽  
First Results ◽  
Scanning Imaging

Abstract. This study describes the retrieval of water vapor vertical distributions in the upper troposphere and lower stratosphere (UTLS) altitude range from space-borne observations of the scattered solar light made in limb viewing geometry. First results using measurements from SCIAMACHY (Scanning Imaging Absorption spectroMeter for Atmospheric CHartographY) aboard ENVISAT (Environmental Satellite) are presented here. In previous publications, the retrieval of water vapor vertical distributions has been achieved exploiting either the emitted radiance leaving the atmosphere or the transmitted solar radiation. In this study, the scattered solar radiation is used as a new source of information on the water vapor content in the UTLS region. A recently developed retrieval algorithm utilizes the differential absorption structure of the water vapor in 1353–1410 nm spectral range and yields the water vapor content in the 11–25 km altitude range. In this study, the retrieval algorithm is successfully applied to SCIAMACHY limb measurements and the resulting water vapor profiles are compared to in situ balloon-borne observations. The results from both satellite and balloon-borne instruments are found to agree typically within 10 %.

scholarly journals Balloon-borne measurements of temperature, water vapor, ozone and aerosol backscatter at the southern slopes of the Himalayas during StratoClim 2016-2017

2018 ◽  
Author(s):  
Simone Brunamonti ◽  
Teresa Jorge ◽  
Peter Oelsner ◽  
Sreeharsha Hanumanthu ◽  
Bhupendra B. Singh ◽  
...  
Keyword(s):  
Water Vapor ◽  
Lower Stratosphere ◽  
Monsoon Season ◽  
Deep Convection ◽  
Lapse Rate ◽  
Boreal Summer ◽  
Aerosol Layer ◽  
Vertical Distributions ◽  
Aerosol Backscatter ◽  
Temperature Water

Abstract. The Asian summer monsoon anticyclone (ASMA) is a major meteorological system of the upper troposphere-lower stratosphere (UTLS) during boreal summer. It is known to be enriched in tropospheric trace gases and aerosols, due to rapid lifting from the boundary layer by deep convection and subsequent horizontal confinement. Given its dynamical structure, the ASMA offers a very efficient pathway for the transport of pollutants to the global stratosphere. Detailed understanding of the ASMA structure and processes requires accurate in-situ measurements. Here we present balloon-borne measurements of temperature, water vapor, ozone and aerosol backscatter conducted within the StratoClim project from two stations at the southern slopes of the Himalayas. In total we performed 63 balloon soundings during two main monsoon-season campaigns, in August 2016 in Nainital, India (NT16AUG) and July–August 2017 in Dhulikhel, Nepal (DK17), and one brief post-monsoon campaign in Nainital in November 2016 (NT16NOV). These measurements provide unprecedented insights into the ASMA thermal structure and its relations to the vertical distributions of water vapor, ozone and aerosols. To study the structure of the UTLS during the monsoon season, we adopt the thermal definition of tropical tropopause layer (TTL), and define the region of altitudes between the lapse rate minimum (LRM) and the cold-point tropopause (CPT) as the Asian Tropopause Transition Layer (ATTL). Further, based on air mass trajectories, we define the Top of Confinement (TOC) level of ASMA, which divides the lower stratosphere (LS) into a Confined LS (CLS), below the TOC and above the CPT, and a Free LS (FLS), above the TOC. Using these thermodynamically-significant boundaries, our analysis reveals that the composition of the UTLS is affected by deep convection up to altitudes 1.5–2 km above the CPT due to the horizontal confinement effect of ASMA. This is shown by enhanced water vapor mixing ratios in the Confined LS compared to background stratospheric values in the Free LS, observed in both NT16AUG (+0.5 ppmv) and DK17 (+0.75 ppmv), and by enhanced aerosol backscatter of the Asian tropopause aerosol layer (ATAL) extending into the Confined LS, as observed in NT16AUG. The CPT was 600 m higher in altitude and 5 K colder in DK17 compared to NT16AUG and strong ozone depletion was found in the ATTL and CLS in DK17, suggesting stronger convective activity during DK17 compared to NT16AUG. An isolated water vapor maximum in the Confined LS, about 1 km above the CPT, was also found in DK17, which we argue is due to overshooting convection hydrating the CLS. These evidence show that the vertical distributions and variability of water vapor, ozone and aerosols in the Asian UTLS are controlled by the top height of the anticyclonic confinement in ASMA, rather than by CPT height as in the conventional understanding of TTL, and suggest that the ASMA contributes to moistening the global stratosphere and to increase its aerosol burden.

Simulation of Atmospheric Motion Vectors for an Observing System Simulation Experiment

2020 ◽  
Vol 37 (3) ◽  
pp. 489-505 ◽  
Author(s):  
Ronald M. Errico ◽  
David Carvalho ◽  
Nikki C. Privé ◽  
Meta Sienkiewicz
Keyword(s):  
Water Vapor ◽  
Feature Tracking ◽  
Simulation Experiment ◽  
System Simulation ◽  
Simulation Experiments ◽  
Motion Vectors ◽  
Vertical Distributions ◽  
Atmospheric Motion ◽  
Atmospheric Motion Vectors ◽  
Observing System Simulation Experiment

AbstractAn algorithm to simulate locations of atmospheric motion vectors for use in observing system simulation experiments is described and demonstrated. It is intended to obviate likely deficiencies in nature run data if used to produce images for feature tracking. The algorithm employs probabilistic functions that are tuned based on distributions of real observations and histograms of nature run fields. For distinct observation types, the algorithm produces geographical and vertical distributions, time-mean counts, and typical spacings of simulated locations that are, at least qualitatively, similar to those of real observations and are associated with nature run cloud and water vapor fields. It thus appears suitable for generating realistic atmospheric motion vectors for use in observing system simulation experiments.

scholarly journals Retrieval of water vapor vertical distributions in the upper troposphere and the lower stratosphere from SCIAMACHY limb measurements

2010 ◽  
Vol 3 (5) ◽  
pp. 4009-4057 ◽  
Author(s):  
A. Rozanov ◽  
K. Weigel ◽  
H. Bovensmann ◽  
S. Dhomse ◽  
K.-U. Eichmann ◽  
...  
Keyword(s):  
Water Vapor ◽  
Solar Radiation ◽  
Lower Stratosphere ◽  
Water Vapor Content ◽  
Retrieval Algorithm ◽  
Altitude Range ◽  
Upper Troposphere ◽  
Vertical Distributions ◽  
First Results

Abstract. This study describes the retrieval of water vapor vertical distributions in the upper troposphere and lower stratosphere (UTLS) altitude range from space-borne observations of the scattered solar light made in limb viewing geometry and presents first results using measurements from SCIAMACHY. In the previous publications, the retrieval of water vapor vertical distributions has been achieved exploiting either the emitted radiance leaving the atmosphere or the transmitted solar radiation. In this study the scattered solar radiation is used as a new source of information on the water vapor content in the UTLS region. A recently developed retrieval algorithm utilizes the differential absorption structure of the water vapor in 1353–1410 nm spectral range and yields the water vapor content in 11–25 km altitude range. In this study the retrieval algorithm is successfully applied to SCIAMACHY limb measurements and the resulting water vapor profiles are compared to in situ balloon-borne observations. The results from both satellite and balloon-borne instruments are found to agree typically within 20%.

Water vapor vertical distributions on Mars: Results from three years of TGO/NOMAD science operations 

2021 ◽  
Author(s):  
Shohei Aoki ◽  
Ann Carine Vandaele ◽  
Frank Daerden ◽  
Geronimo Villanueva ◽  
Giuliano Liuzzi ◽  
...  
Keyword(s):  
Water Vapor ◽  
Dust Storm ◽  
Middle Atmosphere ◽  
Sampling Rate ◽  
Dust Storms ◽  
High Spectral Resolution ◽  
Geophysical Research ◽  
Solar Occultation ◽  
Science Operations ◽  
Vertical Distributions

<div> <p>Nadir and Occultation for Mars Discovery (NOMAD) onboard ExoMars Trace Gas Orbiter (TGO) started  science measurements on 21 April, 2018. Here, we present results on the retrievals of water vapor vertical distributions in the Martian atmosphere from three years of TGO/NOMAD science operations.</p> </div> <p><strong> </strong></p> <p>NOMAD is a spectrometer operating in the spectral ranges between 0.2 and 4.3 μm onboard ExoMars TGO. NOMAD has 3 spectral channels: a solar occultation channel (SO – Solar Occultation; 2.3–4.3 μm), a second infrared channel capable of nadir, solar occultation, and limb sounding (LNO – Limb Nadir and solar Occultation; 2.3–3.8 μm), and an ultraviolet/visible channel (UVIS – Ultraviolet and Visible Spectrometer, 200–650 nm). The infrared channels (SO and LNO) have high spectral resolution (λ/dλ~10,000–20,000) provided by an echelle grating used in combination with an Acousto Optic Tunable Filter (AOTF) which selects diffraction orders. The sampling rate for the solar occultation measurement is 1 second, which provides a good vertical sampling step (~1 km) with higher resolution (~2 km) from the surface to 200 km. Thanks to the instantaneous change of the observing diffraction orders achieved by the AOTF, the SO channel is able to measure five or six different diffraction orders per second in solar occultation mode. In this study, we analyze the solar occultation measurements at diffraction order 134 (3011-3035 cm<sup>-1</sup>), order 136 (3056-3080 cm<sup>-1</sup>), order 168 (3775-3805 cm<sup>-1</sup>), and order 169 (3798-3828 cm<sup>-1</sup>) acquired by the SO channel in order to investigate water vapor vertical distributions.</p> <p>Knowledge of the water vapor vertical profile is important to understand the water cycle and its escape process. Solar occultation measurements by two new spectrometers onboard TGO - NOMAD and Atmospheric Chemistry Suite (ACS) - allows us to daily monitor the water vapor vertical distributions through the whole Martian Year and obtain a good latitudinal coverage for every ~20° of Ls. In 2018, for the first time after 2007, a global dust storm occurred on Mars. It lasted for more than two months (from June to August). Moreover, following the global dust storm, a regional dust storm occurred in January 2019. The NOMAD and ACS observations therefore fully cover the majority of the global and regional dust storms and offer a unique opportunity to study the trace gases distributions during the dust storms. We analyzed those datasets and found a significant increase of water vapor abundances in the middle atmosphere (40-100 km) during the global dust storm from June to mid-September 2018 and the regional dust storm in January 2019. In particular, water vapor reaches very high altitude, at least 100 km, during the global dust storm (Aoki et al., 2019, Journal of Geophysical Research, Volume124, Issue12, Pages 3482-3497, doi:10.1029/2019JE006109). A GCM simulation explained that dust storm related increases of atmospheric temperatures suppress the hygropause, hence reducing ice cloud formation and so allowing water vapor to extend into the middle atmosphere (Neary et al., 2020, Geophysical Research Letters, accepted, Volume47, Issue7, e2019GL084354, doi: 10.1029/2019GL084354). This study presents the results with the extended dataset, which covers a full Mars year. The extended dataset newly includes aphelion season that involves interesting phenomena such as sublimation of water vapor from the northern polar cap and formation of the equatorial cloud belt, which are known as key periods to understand the large north-south hemispheric asymmetries of Mars water vapor. Yet, only a few papers report the water vapor vertical distributions in the aphelion season. The extended dataset also includes the southern summer season (dusty season) in MY 35, which will allow us to compare the water vapor distributions in the global dust storm year with those in the non-global dust storm year. In the presentation, we will discuss the water vapor vertical profiles as well as the aerosols vertical distributions retrieved from the three-year measurements of the TGO/NOMAD.</p>

scholarly journals SCIAMACHY lunar occultation water vapor measurements: retrieval and validation results

2012 ◽  
Vol 5 (1) ◽  
pp. 1029-1073
Author(s):  
F. Azam ◽  
K. Bramstedt ◽  
A. Rozanov ◽  
K. Weigel ◽  
H. Bovensmann ◽  
...  
Keyword(s):  
Water Vapor ◽  
Near Infrared ◽  
Polar Vortex ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Stratospheric Water Vapor ◽  
Lunar Occultation ◽  
Vertical Distributions ◽  
Sensitivity Studies ◽  
Physical And Chemical

Abstract. SCIAMACHY lunar occultation measurements have been used to derive vertical profiles of stratospheric water vapor for the Southern Hemisphere in the near infrared (NIR) spectral range of 1350–1420 nm. The focus of this study is to present the retrieval methodology including the sensitivity studies and optimizations for the implementation of the radiative transfer model on SCIAMACHY lunar occultation measurements. The study also includes the validation of the data product with the collocated measurements from two satellite occultation instruments and two instruments measuring in limb geometry. The SCIAMACHY lunar occultation water vapor measurements comparisons with the ACE-FTS instrument have shown an agreement of 5% on the average that is well within the reported biases of ACE in the stratosphere. The comparisons with HALOE have also shown good results where the agreement between the instruments is within 5%. The validations of the lunar occultation water vapor measurements with MLS instrument are exceptionally good varying between 1.5 to around 4%. The validations with MIPAS are in the range of 10%. A validated dataset of water vapor vertical distributions from SCIAMACHY lunar occultation measurements is expected to facilitate the understanding of physical and chemical processes in the southern mid-latitudes and the dynamical processes related to polar vortex.

New Design for a Differentially Pumped Hydration Chamber for a Siemens IA

1971 ◽  
Vol 29 ◽  
pp. 44-45
Author(s):  
R. C. Moretz ◽  
G. G. Hausner ◽  
D. F. Parsons
Keyword(s):  
Electron Microscopy ◽  
Water Vapor ◽  
Electron Diffraction ◽  
Water Vapor Pressure ◽  
Biological Materials ◽  
Thin Membrane ◽  
Reliable System ◽  
System A ◽  
Water Films ◽  
Aperture Opening

Electron microscopy and diffraction of biological materials in the hydrated state requires the construction of a chamber in which the water vapor pressure can be maintained at saturation for a given specimen temperature, while minimally affecting the normal vacuum of the remainder of the microscope column. Initial studies with chambers closed by thin membrane windows showed that at the film thicknesses required for electron diffraction at 100 KV the window failure rate was too high to give a reliable system. A single stage, differentially pumped specimen hydration chamber was constructed, consisting of two apertures (70-100μ), which eliminated the necessity of thin membrane windows. This system was used to obtain electron diffraction and electron microscopy of water droplets and thin water films. However, a period of dehydration occurred during initial pumping of the microscope column. Although rehydration occurred within five minutes, biological materials were irreversibly damaged. Another limitation of this system was that the specimen grid was clamped between the apertures, thus limiting the yield of view to the aperture opening.

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