scholarly journals Deteksi pengaruh gelombang Kelvin pada fluktuasi uap air di tropopause menggunakan model inversi

2020 ◽  
Vol 34 (1) ◽  
pp. 63
Author(s):  
Dita Fatria Andarini ◽  
Noersomadi Noersomadi
Keyword(s):  
Water Vapor ◽  
Zonal Wind ◽  
Wave Model ◽  
Coupling Model ◽  
Pressure Level ◽  
Vapor Concentration ◽  
Dynamical Process ◽  
Kelvin Wave ◽  
Maximum Value ◽  
Vapor Distribution

Analisis pengaruh gelombang ekuatorial Kelvin terhadap fluktuasi uap air (H2O) di lapisan tropopause (paras tekanan udara 100 hPa), dilakukan dengan  memanfaatkan data Microwave Limb Sounder (MLS) Aura versi 4.2 dan angin zonal NCEP DOE Reanalysis II sepanjang tahun 2017. Model inversi gelombang melalui pendekatan Newtonian diterapkan untuk mencari parameter amplitudo (A) dan fasa (φ) gelombang dominan pada variasi anomali H2O (H2O*). Hasil penyelarasan model inversi menunjukkan perambatan H2O* positif ke arah timur bersesuaian dengan angin zonal (U) positif (angin baratan) yang identik dengan pergerakan gelombang Kelvin. Perambatan ini didominasi oleh bilangan gelombang k1 dengan A1 dan φ1 berturut–turut sebesar 0,44 dan 21,1°.  Penulis menemukan bahwa variasi uap air dipengaruhi oleh perubahan angin baratan menjadi angin timuran dan konvergensi sebesar 0,15 × 10–5 s–1. Analisis komposit diagram relatif terhadap nilai maksimum H2O* menunjukkan adanya pengaruh gelombang ekuatorial Kelvin terhadap distribusi uap air di tropopause. Penelitian terkait pengembangan model kopel troposfer dan stratosfer perlu mempertimbangkan proses dinamika gelombang Kelvin dan proses radiatif dari konsentrasi uap air di tropopause. Analysis on the influence of equatorial Kelvin wave on the fluctuations in water vapor (H2O) at tropopause (100 hPa air pressure level) has been done utilizing Microwave Limb Sounder (MLS) Aura version 4.2 and zonal wind (U) from NCEP DOE Reanalysis II data throughout the year of 2017. The inverse wave model using Newtonian approximation has been applied to determine the dominant of both wave amplitude (A) and phase (φ) parameters on the H2O anomaly (H2O*). The fitting of inverse modeling result showed an eastward propagation of positive H2O* associated with positive U (westerly wind) which is identical as Kelvin wave movement. The propagation is dominated by wavenumber k1 where A1 and φ1 is 0.44 and is 21.1°, respectively.  The authors found that water vapor variations were influenced by the reversal of zonal wind from easterly to easterly and the convergence as large as 0,15 × 10–5 s–1. The composite analysis relative to the maximum value H2O* showed the influence of equatorial Kelvin wave in the water vapor distribution at tropopause. The research on the development of the troposphere –stratosphere coupling model may need to consider the dynamical process of the equatorial Kelvin wave and radiative process of water vapor concentration in the tropopause. 

scholarly journals Analysis of water vapor LIDAR measurements during the MAP campaign: evidence of sub-structures of stratospheric intrusions

2005 ◽  
Vol 5 (5) ◽  
pp. 1301-1310 ◽  
Author(s):  
P. D'Aulerio ◽  
F. Fierli ◽  
F. Congeduti ◽  
G. Redaelli
Keyword(s):  
Water Vapor ◽  
Northern Italy ◽  
Alpine Region ◽  
Vapor Concentration ◽  
Small Scale ◽  
Raman Lidar ◽  
Lidar Measurements ◽  
Stratospheric Intrusions ◽  
Vapor Distribution ◽  
High Potential Vorticity

Abstract. This paper presents two case studies of transport of dry air in the free troposphere measured by a ground based Raman LIDAR in the Northern-Italy, during the Mesoscale Alpine Programme (MAP). Two observations characterized by the presence of anomalously dry layers, below 6 km height, were analyzed using Lagrangian techniques. These events are related to upper-tropospheric, high Potential Vorticity (PV) streamers crossing the Alpine region. These are interpreted as small-scale features of stratospheric intrusions associated with the PV ridge during its phase of dissipation. One of the measurements also shows the presence of two distinct dehydrated structures associated with the same event. The water vapor concentration also suggests dilution processes of dry stratospheric air in the troposphere. Lagrangian simulations allowed to successfully reproduce the observed water vapor distribution and the air parcel histories confirmed the stratospheric origin of the dry layers.

scholarly journals Analysis of water vapor LIDAR measurements during the MAP campaign: evidence of sub-structures of stratospheric intrusions

2004 ◽  
Vol 4 (6) ◽  
pp. 8327-8355 ◽  
Author(s):  
P. D’Aulerio ◽  
F. Fierli ◽  
F. Congeduti ◽  
G. Redaelli
Keyword(s):  
Water Vapor ◽  
Northern Italy ◽  
Alpine Region ◽  
Vapor Concentration ◽  
Small Scale ◽  
Raman Lidar ◽  
Lidar Measurements ◽  
Stratospheric Intrusions ◽  
Vapor Distribution ◽  
High Potential Vorticity

Abstract. This paper presents case studies of dehydration in the free troposphere measured by a ground based Raman LIDAR in the Northern-Italy, during the Mesoscale Alpine Programme (MAP). Two observations characterized by the presence of anomalously dry layers, below 6 km height, were analyzed using Lagrangian techniques. These events are related to upper-tropospheric, high Potential Vorticity streamers crossing the Alpine region and are interpreted as small-scale features of stratospheric intrusions associated to the PV ridge during its breakout phase. One of the measurements also shows the presence of two distinct dehydrated structures associated to the same event. The water vapor concentration also suggests dilution processes of dry stratospheric air in the troposphere. Lagrangian simulations allowed to successfully reproduce the observed water vapor distribution and the air parcel histories confirmed the stratospheric origin of the dry layers.

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.

Degradation of Solid Oxide Fuel Cell Cathodes Accelerated at a High Water Vapor Concentration

2010 ◽  
Vol 7 (2) ◽  
Author(s):  
S. H. Kim ◽  
K. B. Shim ◽  
C. S. Kim ◽  
J. T. Chou ◽  
T. Oshima ◽  
...  
Keyword(s):  
Water Vapor ◽  
Voltage Drop ◽  
Cell Voltage ◽  
High Water ◽  
Solid Oxide ◽  
Constant Current ◽  
Vapor Concentration ◽  
Water Vapor Concentration ◽  
Oxide Fuel ◽  
Constant Current Density

The influence of water vapor in air on power generation characteristic of solid oxide fuel cells was analyzed by measuring cell voltage at a constant current density, as a function of water vapor concentration at 800°C and 1000°C. Cell voltage change was negligible at 1000°C, while considerable voltage drop was observed at 800°C accelerated at high water vapor concentrations of 20 wt % and 40 wt %. It is considered that La2O3 formed on the (La0.8Sr0.2)0.98MnO3 surface, which is assumed to be the reason for a large voltage drop.

scholarly journals A Coated Spherical Microresonator for Measurement of Water Vapor Concentration at PPM Levels in Very Low Humidity Environments

2018 ◽  
Vol 36 (13) ◽  
pp. 2667-2674 ◽  
Author(s):  
Arun Kumar Mallik ◽  
Gerald Farrell ◽  
Dejun Liu ◽  
Vishnu Kavungal ◽  
Qiang Wu ◽  
...  
Keyword(s):  
Water Vapor ◽  
Vapor Concentration ◽  
Water Vapor Concentration ◽  
Low Humidity

Simultaneous water vapor concentration and temperature measurements in unsteady hydrogen flames

2009 ◽  
Vol 32 (2) ◽  
pp. 2527-2534 ◽  
Author(s):  
David Blunck ◽  
Sumit Basu ◽  
Yuan Zheng ◽  
Viswanath Katta ◽  
Jay Gore
Keyword(s):  
Water Vapor ◽  
Temperature Measurements ◽  
Vapor Concentration ◽  
Water Vapor Concentration

scholarly journals DESIGNING A SMALL CLIMATE CHAMBER TO CHARACTERIZE PEOPLE AS A SOURCE OF DETERIORATION OF INDOOR AIR QUALITY BY RESPIRATION

2019 ◽  
Vol 7 ◽  
pp. 954-959 ◽  
Author(s):  
Detelin Ganchev Markov ◽  
Sergey Mijorski ◽  
Peter Stankov ◽  
Iskra Simova ◽  
Radositna A. Angelova ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Water Vapor ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Carbon Dioxide Concentration ◽  
Air Distribution ◽  
Vapor Concentration ◽  
Cfd Simulations ◽  
Climate Chamber

: People are one of the sources for deterioration of the indoor air quality. They worsen indoor air quality by their presence (respiration, bio-effluents), activities and habits. Through respiration, people decrease the oxygen concentration in the air of the occupied space and increase carbon dioxide and water vapor concentration in the indoor air as well as its temperature. The goal of the AIRMEN project is to find out if the rate of consumption of oxygen and emission of carbon dioxide (and water vapor) by people depends on the indoor air temperature as well as carbon dioxide concentration in the inhaled air. In order to achieve this goal a small climate chamber must be designed and constructed which allows for controlling and measuring both inflow and exposure parameters as well as for measuring outflow parameters. The principal goal of this paper is to present some important details, obtained by CFD simulations, from the design process of the climate chamber which precondition the air distribution in the chamber and hence the exposure parameters.

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.

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