Water-vapor Measurements in the Lower Stratosphere

1974 ◽  
Vol 52 (8) ◽  
pp. 1527-1531 ◽  
Author(s):  
H. J. Mastenbrook
Keyword(s):  
Water Vapor ◽  
Lower Stratosphere ◽  
Marked Decrease ◽  
Vapor Concentration ◽  
Water Vapor Concentration ◽  
Mixing Ratio ◽  
Stratospheric Water Vapor ◽  
Mixing Ratios ◽  
Natural Concentration ◽  
General Range

Nearly 10 years of water-vapor measurements to heights of 30 km provide a basis for assessing the natural concentration of stratospheric water vapor and its variability. The measurements which began in 1964 have been made at monthly intervals from the mid-latitude location of Washington, D.C, using a balloon-borne frost-point hygrometer. The observations show the mixing ratio of water-vapor mass to air mass in the stratosphere to be in the general range of 1 to 4 p.p.m. with a modal concentration between 2 and 3 p.p.m. An annual cycle of mixing ratio is evident for the low stratosphere. A trend of water-vapor increase observed during the first 6 years does not persist beyond 1969 or 1970. The 6 year increase was followed by a marked decrease in 1971, with mixing ratios remaining generally below 3 p.p.m. thereafter. The measurements of recent years suggest that the series of observations may have begun during a period of low water-vapor concentration in the stratosphere.

scholarly journals Testing the Fixed Anvil Temperature Hypothesis in a Cloud-Resolving Model

2007 ◽  
Vol 20 (10) ◽  
pp. 2051-2057 ◽  
Author(s):  
Zhiming Kuang ◽  
Dennis L. Hartmann
Keyword(s):  
Water Vapor ◽  
Vapor Concentration ◽  
Water Vapor Concentration ◽  
Mixing Ratio ◽  
Microphysics Scheme ◽  
Temperature Changes ◽  
Stratospheric Water Vapor ◽  
Cloud Resolving Model

Abstract Using cloud-resolving simulations of tropical radiative–convective equilibrium, it is shown that the anvil temperature changes by less than 0.5 K with a 2-K change in SST, lending support to the fixed anvil temperature (FAT) hypothesis. The results suggest that for plausible ozone profiles, a decrease in the air’s emission capability instead of ozone heating shall remain the control on the detrainment level, and the FAT hypothesis should hold. The anvil temperature also remains unchanged with other changes in the system such as the doubled CO2 mixing ratio, doubled stratospheric water vapor concentration, and dynamical cooling due to the Brewer–Dobson circulations. The results are robust when a different microphysics scheme is used.

scholarly journals Modeling upper tropospheric and lower stratospheric water vapor anomalies

2013 ◽  
Vol 13 (4) ◽  
pp. 9653-9679 ◽  
Author(s):  
M. R. Schoeberl ◽  
A. E. Dessler ◽  
T. Wang
Keyword(s):  
Water Vapor ◽  
Lower Stratosphere ◽  
Calculation Model ◽  
Vapor Concentration ◽  
Cold Temperatures ◽  
Tropical Tropopause Layer ◽  
Stratospheric Water Vapor ◽  
Tropical Tropopause ◽  
Minimum Displacement ◽  
Asian Monsoons

Abstract. The domain-filling, forward trajectory calculation model developed by Schoeberl and Dessler (2011) is used to further investigate processes that produce upper tropospheric and lower stratospheric water vapor anomalies. We examine the pathways parcels take from the base of the tropical tropopause layer (TTL) to the lower stratosphere. Most parcels found in the lower stratosphere arise from East Asia, the Tropical West Pacific (TWP) and the Central/South America. The belt of TTL parcel origins is very wide compared to the final dehydration zones near the top of the TTL. This is due to the convergence of rising air as a result of the stronger diabatic heating near the tropopause relative to levels above and below. The observed water vapor anomalies – both wet and dry – correspond to regions where parcels have minimal displacement from their initialization. These minimum displacement regions include the winter TWP and the Asian and American monsoons. To better understand the stratospheric water vapor concentration we introduce the water vapor spectrum and investigate the source of the wettest and driest components of the spectrum. We find that the driest air parcels that originate below the TWP, moving upward to dehydrate in the TWP cold upper troposphere. The wettest air parcels originate at the edges of the TWP as well as the summer American and Asian monsoons. The wet air parcels are important since they skew the mean stratospheric water vapor distribution toward higher values. Both TWP cold temperatures that produce dry parcels as well as extra-TWP processes that control the wet parcels determine stratospheric water vapor.

scholarly journals Intercomparison of two cavity ring-down spectroscopy analyzers for atmospheric <sup>13</sup>CO<sub>2</sub>  ∕ <sup>12</sup>CO<sub>2</sub> measurement

2016 ◽  
Vol 9 (8) ◽  
pp. 3879-3891 ◽  
Author(s):  
Jiaping Pang ◽  
Xuefa Wen ◽  
Xiaomin Sun ◽  
Kuan Huang
Keyword(s):  
Water Vapor ◽  
Co2 Concentration ◽  
Calibration Method ◽  
Vapor Concentration ◽  
Water Vapor Concentration ◽  
Mixing Ratio ◽  
Ambient Conditions ◽  
Significant Linear Correlation ◽  
The Difference ◽  
Water Vapor Mixing Ratio

Abstract. Isotope ratio infrared spectroscopy (IRIS) permits continuous in situ measurement of CO2 isotopic composition under ambient conditions. Previous studies have mainly focused on single IRIS instrument performance; few studies have considered the comparability among different IRIS instruments. In this study, we carried out laboratory and ambient measurements using two Picarro CO2δ13C analyzers (G1101-i and G2201-i (newer version)) and evaluated their performance and comparability. The best precision was 0.08–0.15 ‰ for G1101-i and 0.01–0.04 ‰ for G2201-i. The dependence of δ13C on CO2 concentration was 0.46 ‰ per 100 ppm and 0.09 ‰ per 100 ppm, the instrument drift ranged from 0.92–1.09 ‰ and 0.19–0.37 ‰, and the sensitivity of δ13C to the water vapor mixing ratio was 1.01 ‰ ∕ % H2O and 0.09 ‰ ∕ % H2O for G1101-i and G2201-i, respectively. The accuracy after correction by the two-point mixing ratio gain and offset calibration method ranged from −0.04–0.09 ‰ for G1101-i and −0.13–0.03 ‰ for G2201-i. The sensitivity of δ13C to the water vapor mixing ratio improved from 1.01 ‰ ∕ % H2O before the upgrade of G1101-i (G1101-i-original) to 0.15 ‰ ∕ % H2O after the upgrade of G1101-i (G1101-i-upgraded). Atmospheric δ13C measured by G1101-i and G2201-i captured the rapid changes in atmospheric δ13C signals on hourly to diurnal cycle scales, with a difference of 0.07 ± 0.24 ‰ between G1101-i-original and G2201-i and 0.05 ± 0.30 ‰ between G1101-i-upgraded and G2201-i. A significant linear correlation was observed between the δ13C difference of G1101-i-original and G2201-i and the water vapor concentration, but there was no significant correlation between the δ13C difference of G1101-i-upgraded and G2201-i and the water vapor concentration. The difference in the Keeling intercept values decreased from 1.24 ‰ between G1101-i-original and G2201-i to 0.36 ‰ between G1101-i-upgraded and G2201-i, which indicates the importance of consistency among different IRIS instruments.

Direct injection of water vapor into the lower stratosphere through extreme convection: A case study for the summer 2019 in the mid latitudes

2020 ◽  
Author(s):  
Dina Khordakova ◽  
Christian Rolf ◽  
Martina Krämer ◽  
Martin Riese
Keyword(s):  
Water Vapor ◽  
Satellite Images ◽  
Lower Stratosphere ◽  
Global Climate ◽  
Direct Injection ◽  
Reanalysis Data ◽  
Radiation Budget ◽  
Mixing Ratio ◽  
Mixing Ratios ◽  
Water Vapor Mixing Ratio

&lt;p&gt;Water vapor is one of the strongest greenhouse gases of the atmosphere. Its driving role in the upper troposphere / lower stratosphere region (UTLS) for the radiation budget was shown by e.g. Riese et al., (2012). Despite its low abundance of 4 - 6 ppmv in the stratosphere, even small changes in its mixing ratio can leed to a positive feedback to global warming. To better understand changes and variability of water vapor in the lower stratosphere, we focus here on exchange processes from the moist troposphere to the dry stratosphere in the mid latitudes. These processes are caused by extreme vertical convection, which is expected to increase in intensity and frequency with progressive global climate change.&lt;/p&gt;&lt;p&gt;Within the MOSES (Modular Observation Solutions for Earth Systems) campaign in the summer of 2019, two extreme vertical convection events could be captured with balloon borne humidity sensors over the eastern part of Germany. The comparison of measurements before and after both events reveal distinct water vapor enhancements in the lower stratosphere and show that even in mid-latitudes over shooting convection can impact the water vapor mixing ratio in the UTLS. The measurements are compared with the Microwave Limb Sounder (MLS) data as well as ECMWF reanalysis data.&lt;/p&gt;&lt;p&gt;&lt;span&gt;We will show a deeper analysis of both events by using visible and infrared weather satellite images in combination with meteorological fields of ECMWF. &lt;/span&gt;&lt;span&gt;B&lt;/span&gt;&lt;span&gt;ackward trajectories of the air masses &lt;/span&gt;&lt;span&gt;with the enriched water vapor mixing ratios &lt;/span&gt;&lt;span&gt;calculated with&lt;/span&gt;&lt;span&gt; the CLAMS model &lt;/span&gt;&lt;span&gt;and&lt;/span&gt; &lt;span&gt;combined&lt;/span&gt;&lt;span&gt; with the satellite images can &lt;/span&gt;&lt;span&gt;confirm the convective origin. &lt;/span&gt;&lt;span&gt;Additionally,&lt;/span&gt;&lt;span&gt; we show the &lt;/span&gt;&lt;span&gt;further &lt;/span&gt;&lt;span&gt;development of this distinct water vapor filaments within the lower stratosphere &lt;/span&gt;&lt;span&gt;in order to&lt;/span&gt;&lt;span&gt; trace the transport and mixing process, &lt;/span&gt;&lt;span&gt;based on an&lt;/span&gt; &lt;span&gt;analysis of forward trajectories.&lt;/span&gt;&lt;/p&gt;

scholarly journals Modeling upper tropospheric and lower stratospheric water vapor anomalies

2013 ◽  
Vol 13 (15) ◽  
pp. 7783-7793 ◽  
Author(s):  
M. R. Schoeberl ◽  
A. E. Dessler ◽  
T. Wang
Keyword(s):  
Water Vapor ◽  
Lower Stratosphere ◽  
Calculation Model ◽  
Vapor Concentration ◽  
Cold Temperatures ◽  
Tropical Tropopause Layer ◽  
Stratospheric Water Vapor ◽  
Tropical Tropopause ◽  
Minimum Displacement ◽  
Asian Monsoons

Abstract. The domain-filling, forward trajectory calculation model developed by Schoeberl and Dessler (2011) is used to further investigate processes that produce upper tropospheric and lower stratospheric water vapor anomalies. We examine the pathways parcels take from the base of the tropical tropopause layer (TTL) to the lower stratosphere. Most parcels found in the lower stratosphere arise from East Asia, the Tropical West Pacific (TWP) and Central/South America. The belt of TTL parcel origins is very wide compared to the final dehydration zones near the top of the TTL. This is due to the convergence of rising air due to the stronger diabatic heating near the tropopause relative to levels above and below. The observed water vapor anomalies – both wet and dry – correspond to regions where parcels have minimal displacement from their initialization. These minimum displacement regions include the winter TWP and the Asian and American monsoons. To better understand the stratospheric water vapor concentration we introduce the water vapor spectrum and investigate the source of the wettest and driest components of the spectrum. We find that the driest air parcels originate below the TWP, moving upward to dehydrate in the TWP cold upper troposphere. The wettest air parcels originate at the edges of the TWP as well as in the summer American and Asian monsoons. The wet air parcels are important since they skew the mean stratospheric water vapor distribution toward higher values. Both TWP cold temperatures that produce dry parcels as well as extra-TWP processes that control the wet parcels determine stratospheric water vapor.

scholarly journals Cloud-Assisted Retrieval of Lower-Stratospheric Water Vapor from Nadir-View Satellite Measurements

2018 ◽  
Vol 35 (3) ◽  
pp. 541-553 ◽  
Author(s):  
Jing Feng ◽  
Yi Huang
Keyword(s):  
Water Vapor ◽  
Vapor Concentration ◽  
Small Scale ◽  
Water Vapor Concentration ◽  
Satellite Measurements ◽  
Atmospheric Infrared Sounder ◽  
Stratospheric Water Vapor ◽  
Retrieval Problem ◽  
Elevated Water ◽  
Aircraft Data

AbstractThis study examines the feasibility of retrieving lower-stratospheric water vapor using a nadir infrared hyperspectrometer, with the focus on the detectability of small-scale water vapor variability. The feasibility of the retrieval is examined using simulation experiments that model different instrument settings. These experiments show that the infrared spectra, measured with sufficient spectral coverage, resolution, and noise level, contain considerable information content that can be used to retrieve lower-stratospheric water vapor. Interestingly, it is found that the presence of an opaque cloud layer at the tropopause level can substantially improve the retrieval performance, as it helps remove the degeneracy in the retrieval problem. Under this condition, elevated lower-stratospheric water vapor concentration—for instance, caused by convective moistening—can be detected with an accuracy of 0.09 g m−2 using improved spaceborne hyperspectrometers. The cloud-assisted retrieval is tested using the measurements of the Atmospheric Infrared Sounder (AIRS). Validation against collocated aircraft data shows that the retrieval can detect the elevated water vapor concentration caused by convective moistening.

scholarly journals UV Absorption Hygrometer for Fast-Response Airborne Water Vapor Measurements

2012 ◽  
Vol 29 (9) ◽  
pp. 1295-1303 ◽  
Author(s):  
Stuart P. Beaton ◽  
Mike Spowart
Keyword(s):  
Water Vapor ◽  
Vacuum Ultraviolet ◽  
Fast Response ◽  
High Rate ◽  
Vapor Concentration ◽  
Mixing Ratio ◽  
Lyman Alpha ◽  
High Data ◽  
Mixing Ratios ◽  
Research Aircraft

Abstract A next-generation vacuum-ultraviolet (Lyman-alpha) absorption hygrometer for high-rate research aircraft humidity measurements designed by the National Center for Atmospheric Research is described. It retains the high data rate, optical and mechanical simplicity, and low maintenance of previous Lyman-alpha hygrometers, while incorporating modern electronics and rugged, long-lived commercially available lamps and detectors. The mass of the sensing head is 2.0 kg in a volume of 3700 cm3, while the power supply is 1.3 kg mass in a volume of 1100 cm3. Power draw is 0.2 A at 120 V alternating current (AC). In bench and aircraft flight testing the prototype shows a bandwidth of 35 Hz and mixing ratio noise of ±0.5% over a water vapor mixing ratio range of 2–15 g kg−1. This range can be scaled to lower mixing ratios by increasing the pathlength. This performance enables measurements of water vapor concentration with high spatial resolution from research aircraft. The prototype instrument has flown over 380 h with minimal maintenance or repairs.

The seasonal correlation between atmospheric water vapor and aerosol extinction and the relationship between aerosol, NO2, SO2 and water vapor during haze pollution in Qingdao, China

2020 ◽  
Author(s):  
Hongmei Ren ◽  
Ang Li ◽  
Zhaokun Hu ◽  
Yeyuan Huang ◽  
Jin Xu ◽  
...  
Keyword(s):  
Water Vapor ◽  
Moisture Absorption ◽  
Vapor Concentration ◽  
Water Vapor Concentration ◽  
Aerosol Extinction ◽  
Mixing Ratio ◽  
Haze Pollution ◽  
Water Vapor Mixing Ratio ◽  
Seasonal Correlation ◽  
The Relationship

&lt;p&gt;MAX-DOAS observations was carried out from March 1, 2019 to December 31, 2019 in Qingdao, China, to measure the O&lt;sub&gt;4&lt;/sub&gt;, NO&lt;sub&gt;2&lt;/sub&gt;, SO&lt;sub&gt;2&lt;/sub&gt; and H&lt;sub&gt;2&lt;/sub&gt;O absorption, to retrieve AOD and the troposphere vertical column concentration of NO&lt;sub&gt;2&lt;/sub&gt;, SO&lt;sub&gt;2&lt;/sub&gt; and H&lt;sub&gt;2&lt;/sub&gt;O.We use PriAM algorithm which based on the optimal estimation to calculating volume mixing ratio profile of trace gases, aerosol and water vapor during 0 ~ 4 km. The correlation between AOD and H&lt;sub&gt;2&lt;/sub&gt;O VCD was analyzed in every month, the results showed that the AOD and H&lt;sub&gt;2&lt;/sub&gt;O VCD has good linear relationship in each month., illustrate the increase of water vapor concentration will lead to the increase of moisture absorption of aerosol. The seasonal variation of the four seasonal correlation slopes in the order of summer &lt; autumn &lt; spring &lt; winter. The influence of concentration change of NO&lt;sub&gt;2&lt;/sub&gt; VCD, SO&lt;sub&gt;2&lt;/sub&gt; VCD, H&lt;sub&gt;2&lt;/sub&gt;O VCD and AOD is discussed in a haze episodes occurred in December 2019. Discovery that the H&lt;sub&gt;2&lt;/sub&gt;O VCD and AOD was increased at the same time in the haze pollution incident, but with the increase of water vapor concentration, the concentration of NO&lt;sub&gt;2&lt;/sub&gt; and SO&lt;sub&gt;2&lt;/sub&gt; decreases, indicated that due to the increase of concentration of water vapor, NO&lt;sub&gt;2&lt;/sub&gt; and SO&lt;sub&gt;2&lt;/sub&gt; heterogeneous reaction will happen to generate nitrate and sulfate aerosols, so that the concentration of NO&lt;sub&gt;2&lt;/sub&gt; and SO&lt;sub&gt;2 &lt;/sub&gt;concentration was decreased. The relationship between NO&lt;sub&gt;2&lt;/sub&gt;, SO&lt;sub&gt;2&lt;/sub&gt;, AOD and water vapor mixing ratio of 50m, 200m, 400m and 600m during haze pollution period was also studied, and it was indicated that phenomenon aerosol extinction increased with the increase of water vapor mixing ratio, while NO&lt;sub&gt;2&lt;/sub&gt; and SO&lt;sub&gt;2&lt;/sub&gt;, on the contrary, were more obvious at 50m and 200m near the ground.&lt;/p&gt;

scholarly journals Numerical Simulation of the Water Vapor Separation of a Moisture-Selective Hollow-Fiber Membrane for the Application in Wood Drying Processes

Membranes ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 593
Author(s):  
Nasim Alikhani ◽  
Douglas W. Bousfield ◽  
Jinwu Wang ◽  
Ling Li ◽  
Mehdi Tajvidi
Keyword(s):  
Water Vapor ◽  
Constant Temperature ◽  
Hollow Fiber ◽  
Hollow Fiber Membrane ◽  
Vacuum Pressure ◽  
Vapor Concentration ◽  
Water Vapor Concentration ◽  
Fiber Membrane ◽  
Wood Drying ◽  
Air Velocity

In this study, a simplified two-dimensional axisymmetric finite element analysis (FEA) model was developed, using COMSOL Multiphysics® software, to simulate the water vapor separation in a moisture-selective hollow-fiber membrane for the application of air dehumidification in wood drying processes. The membrane material was dense polydimethylsiloxane (PDMS). A single hollow fiber membrane was modelled. The mass and momentum transfer equations were simultaneously solved to compute the water vapor concentration profile in the single hollow fiber membrane. A water vapor removal experiment was conducted by using a lab-scale PDMS hollow fiber membrane module operated at constant temperature of 35 °C. Three operation parameters of air flow rate, vacuum pressure, and initial relative humidity (RH) were set at different levels. The final RH of dehydrated air was collected and converted to water vapor concentration to validate simulated results. The simulated results were fairly consistent with the experimental data. Both experimental and simulated results revealed that the water vapor removal efficiency of the membrane system was affected by air velocity and vacuum pressure. A high water vapor removal performance was achieved at a slow air velocity and high vacuum pressure. Subsequently, the correlation of Sherwood (Sh)–Reynolds (Re)–Schmidt (Sc) numbers of the PDMS membrane was established using the validated model, which is applicable at a constant temperature of 35 °C and vacuum pressure of 77.9 kPa. This study delivers an insight into the mass transport in the moisture-selective dense PDMS hollow fiber membrane-based air dehumidification process, with the aims of providing a useful reference to the scale-up design, process optimization and module development using hollow fiber membrane materials.

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