New Insights into Diffusive Kinetic Fractionation During Liquid Condensation Under Supersaturated Environment: A Novel Approach for Isotope Tagging of Ground Level Water Vapor

2021 ◽  
Author(s):  
Akash Ganguly ◽  
Virendra Padhya ◽  
Harsh Oza ◽  
Bhishm Kumar ◽  
P. Nagabhushanam ◽  
...  
Keyword(s):  
Water Vapor ◽  
Ground Level ◽  
Novel Approach ◽  
Kinetic Fractionation

Kinetic effects during ocean evaporation: observed relationship with wind speed 

2021 ◽  
Author(s):  
Daniele Zannoni ◽  
Hans Christian Steen-Larsen ◽  
Andrew Peters ◽  
Árný Erla Sveinbjörnsdóttir
Keyword(s):  
Water Vapor ◽  
Wind Speed ◽  
Water Interface ◽  
Fractionation Factor ◽  
Wind Speeds ◽  
Air Water Interface ◽  
Kinetic Fractionation ◽  
Speed Effect ◽  
Equilibrium Fractionation ◽  
Non Equilibrium

<p>Water vapor has a fundamental role in weather and climate, being the strongest natural greenhouse gas in the Earth’s atmosphere. The main source of water vapor in the atmosphere is ocean evaporation, which transfers a large amount of energy via latent heat fluxes. In the past, evaporation was intensively studied using stable isotopes because of the large fractionation effects involved during water phase changes, providing insights on processes occurring at the air-water interface. Current theories describe evaporation near the air-water interface as a combination of molecular and turbulent diffusion processes into separated sublayers. The importance of those two sublayers, in terms of total resistance to vapor transport in air, is expected to be dependent on parameters such as moisture deficit, temperature and wind speed. Non-equilibrium fractionation effects in isotopic evaporation models are then expected to be related to these physical parameters. In the last 10 years, several water vapor observations from oceanic expeditions were focused on the impact of temperature and wind speed effect, assuming the influence of those parameters on non-equilibrium fractionation in the marine boundary layer. Wind speed effect is expected to be small on total kinetic fractionation and was discussed at length but was not completely ruled out. With a gradient-diffusion approach (2 heights above the ocean surface) and Cavity Ring-Down Spectroscopy we have estimated non-equilibrium fractionation factors for <sup>18</sup>O/<sup>16</sup>O during evaporation, showing that the wind speed effect can be detected and has no significant impact on kinetic fractionation. Results obtained for wind speeds between 0 and 10 m s<sup>-1</sup> in the North Atlantic Ocean are consistent with the Merlivat and Jouzel (1979) parametrization for smooth surfaces (mean ε<sub>18</sub>=6.1‰). A small monotonic decrease of the fractionation parameter is observed as a function of 10 m wind speed (slope  ≅ 0.15 ‰ m<sup>-1</sup> s), without any evident discontinuity. However, depending on the data filtering approach it is possible to highlight a rapid decrease of the kinetic fractionation factor at low wind speed (≤ 2.5 m s<sup>-1</sup>). An evident decrease of fractionation factor is also observed for wind speeds above 10 m s<sup>-1</sup>, allowing to hypothesize the possible effect of sea spray in net evaporation flux. Considering the average wind speed over the oceans, we conclude that a constant kinetic fractionation factor for evaporation is a more simple and reasonable solution than a wind-speed dependent parametrization. </p><p> </p><p>Merlivat, L., & Jouzel, J. (1979). Global climatic interpretation of the deuterium‐oxygen 18 relationship for precipitation. Journal of Geophysical Research: Oceans, 84(C8), 5029-5033.</p>

scholarly journals A Novel Approach for the Detection of Developing Thunderstorm Cells

2019 ◽  
Vol 11 (4) ◽  
pp. 443 ◽  
Author(s):  
Richard Müller ◽  
Stéphane Haussler ◽  
Matthias Jerg ◽  
Dirk Heizenreder
Keyword(s):  
Water Vapor ◽  
Main Idea ◽  
Probability Of Detection ◽  
Base Case ◽  
Convective Clouds ◽  
Critical Success ◽  
Novel Approach ◽  
Forecast Lead Time ◽  
Spatio Temporal ◽  
Atmospheric Motion Vectors

This study presents a novel approach for the early detection of developing thunderstorms. To date, methods for the detection of developing thunderstorms have usually relied on accurate Atmospheric Motion Vectors (AMVs) for the estimation of the cooling rates of convective clouds, which correspond to the updraft strengths of the cloud objects. In this study, we present a method for the estimation of the updraft strength that does not rely on AMVs. The updraft strength is derived directly from the satellite observations in the SEVIRI water vapor channels. For this purpose, the absolute value of the vector product of spatio-temporal gradients of the SEVIRI water vapor channels is calculated for each satellite pixel, referred to as Normalized Updraft Strength (NUS). The main idea of the concept is that vertical updraft leads to NUS values significantly above zero, whereas horizontal cloud movement leads to NUS values close to zero. Thus, NUS is a measure of the strength of the vertical updraft and can be applied to distinguish between advection and convection. The performance of the method has been investigated for two summer periods in 2016 and 2017 by validation with lightning data. Values of the Critical Success Index (CSI) of about 66% for 2016 and 60% for 2017 demonstrate the good performance of the method. The Probability of Detection (POD) values for the base case are 81.8% for 2016 and 89.2% for 2017, respectively. The corresponding False Alarm Ratio (FAR) values are 22.6% (2016) and 36.4% (2017), respectively. In summary, the method has the potential to reduce forecast lead time significantly and can be quite useful in regions without a well-maintained radar network.

Laser Absorption Techniques for the Measurementof Atmospheric Water Vapor Concentration

1977 ◽  
Vol 16 (10) ◽  
pp. 1072-1076 ◽  
Author(s):  
E. Brannen ◽  
Z. Kucerovsky
Keyword(s):  
Water Vapor ◽  
Laser Radiation ◽  
Response Time ◽  
Water Vapor Pressure ◽  
Ground Level ◽  
Fast Response ◽  
Vapor Concentration ◽  
Water Vapor Concentration ◽  
Laser Method ◽  
Laser Experiments

Abstract A sensitive laser method with fast response time has been developed which is suitable for measuringatmospheric water vapor concentration. The method utilizes the absorption of 33.02 and 27.972 pm radiationfrom a water vapor laser. Experiments were carried out in a 2 m controlled atmosphere absorption cell atconditions corresponding to ground-level to high-altitude atmospheric pressures. Typically, an absorptionof 1% was produced in a 1 m path length by a water vapor pressure of 1.1 Pa at ground level and 2.2 Paat 5 km using 33.02 pm laser radiation. With 27,972 pm laser radiation the absorption is about a factor 50less and can be used when higher concentrations of water vapor are encountered. The response time of thedetecting apparatus can be less than a second and still achieve these sensitivities. Possibilities of building anairborne instrument for measuring water vapor concentration are discussed.

scholarly journals A new approach for flow-through respirometry measurements in humans

2010 ◽  
Vol 298 (6) ◽  
pp. R1571-R1579 ◽  
Author(s):  
Edward L. Melanson ◽  
Jan P. Ingebrigtsen ◽  
Audrey Bergouignan ◽  
Kazunori Ohkawara ◽  
Wendy M. Kohrt ◽  
...  
Keyword(s):  
Water Vapor ◽  
Relative Humidity ◽  
Gas Exchange ◽  
Flow Rate ◽  
Water Vapor Pressure ◽  
Propane Combustion ◽  
Pull System ◽  
Novel Approach ◽  
Flow Through ◽  
Combustion Tests

Indirect whole room calorimetry is commonly used in studies of human metabolism. These calorimeters can be configured as either push or pull systems. A major obstacle to accurately calculating gas exchange rates in a pull system is that the excurrent flow rate is increased above the incurrent flow rate, because the organism produces water vapor, which also dilutes the concentrations of respiratory gasses in the excurrent sample. A common approach to this problem is to dry the excurrent gasses prior to measurement, but if drying is incomplete, large errors in the calculated oxygen consumption will result. The other major potential source of error is fluctuations in the concentration of O2 and CO2 in the incurrent airstream. We describe a novel approach to measuring gas exchange using a pull-type whole room indirect calorimeter. Relative humidity and temperature of the incurrent and excurrent airstreams are measured continuously using high-precision, relative humidity and temperature sensors, permitting accurate measurement of water vapor pressure. The excurrent flow rates are then adjusted to eliminate the flow contribution from water vapor, and respiratory gas concentrations are adjusted to eliminate the effect of water vapor dilution. In addition, a novel switching approach is used that permits constant, uninterrupted measurement of the excurrent airstream while allowing frequent measurements of the incurrent airstream. To demonstrate the accuracy of this approach, we present the results of validation trials compared with our existing system and metabolic carts, as well as the results of standard propane combustion tests.

scholarly journals AIR QUALITY MONITORING AND DATA MANAGEMENT IN GERMANY – STATUS QUO AND SUGGESTIONS FOR IMPROVEMENT

2020 ◽  
Vol XLIV-4/W2-2020 ◽  
pp. 37-43
Author(s):  
L. Petry ◽  
H. Herold ◽  
G. Meinel ◽  
T. Meiers ◽  
I. Müller ◽  
...  
Keyword(s):  
Decision Making ◽  
Air Quality ◽  
Management Practices ◽  
System Development ◽  
Ground Level ◽  
Ground Level Ozone ◽  
Novel Approach ◽  
Depth Analysis ◽  
New Generation

Abstract. This paper proposes a novel approach to facilitate air quality aware decision making and to support planning actors to take effective measures for improving the air quality in cities and regions. Despite many improvements over the past decades, air pollutants such as particulate matter (PM), nitrogen dioxide (NO2) and ground-level ozone (O3) pose still one of the major risks to human health and the environment. Based on both a general analysis of the air quality situation and regulations in the EU and Germany as well as an in-depth analysis of local management practices requirements for better decision making are identified. The requirements are used to outline a system architecture following a co-design approach, i.e., besides scientific and industry partners, local experts and administrative actors are actively involved in the system development. Additionally, the outlined system incorporates two novel methodological strands: (1) it employs a deep neural network (DNN) based data analytics approach and (2) makes use of a new generation of satellite data, namely Sentinel-5 Precursor (Sentinel-5P). Hence, the system allows for providing areal and high-resolution (e.g., street-level) real-time and forecast (up to 48 hours) data to inform decision makers for taking appropriate short-term measures, and secondly, to simulate air quality under different planning options and long-term actions such as modified traffic flows and various urban layouts.

scholarly journals DESIGN AND RESULTS OF AN AI-BASED FORECASTING OF AIR POLLUTANTS FOR SMART CITIES

2021 ◽  
Vol VIII-4/W1-2021 ◽  
pp. 89-96
Author(s):  
L. Petry ◽  
T. Meiers ◽  
D. Reuschenberg ◽  
S. Mirzavand Borujeni ◽  
J. Arndt ◽  
...  
Keyword(s):  
Air Quality ◽  
Air Pollutants ◽  
Smart Cities ◽  
Meteorological Data ◽  
Weather Forecast ◽  
Ground Level ◽  
Urban Environments ◽  
Air Pollutant ◽  
Novel Approach

Abstract. This paper presents the design and the results of a novel approach to predict air pollutants in urban environments. The objective is to create an artificial intelligence (AI)-based system to support planning actors in taking effective and adequate short-term measures against unfavourable air quality situations. In general, air quality in European cities has improved over the past decades. Nevertheless, reductions of the air pollutants particulate matter (PM), nitrogen dioxide (NO2) and ground-level ozone (O3), in particular, are essential to ensure the quality of life and a healthy life in cities. To forecast these air pollutants for the next 48 hours, a sequence-to-sequence encoder-decoder model with a recurrent neural network (RNN) was implemented. The model was trained with historic in situ air pollutant measurements, traffic and meteorological data. An evaluation of the prediction results against historical data shows high accordance with in situ measurements and implicate the system’s applicability and its great potential for high quality forecasts of air pollutants in urban environments by including real time weather forecast data.

Application of Computer-Simulated Infrared Solar Spectra to the Detection of Atmospheric Fluorocarbon-12

1977 ◽  
Vol 31 (3) ◽  
pp. 224-229 ◽  
Author(s):  
Robert J. Nordstrom ◽  
John H. Shaw ◽  
Wilbert R. Skinner ◽  
Walter H. Chan ◽  
Jack G. Calvert ◽  
...  
Keyword(s):  
Water Vapor ◽  
Ground Level ◽  
Half Width ◽  
Absorption Feature ◽  
Atmospheric Transmission ◽  
Water Vapor Absorption ◽  
Cambridge Research ◽  
Ground Level Concentration ◽  
Transmission Window ◽  
Lorentz Line

Fluorocarbon-12 (CCl2F2) has been detected in the atmosphere by observation of infrared solar spectra in two spectral regions of the 8 to 12 µm atmospheric transmission window. The solar spectra were compared with laboratory spectra of CCl2F2 and also with computer synthesized spectra which were generated from the most recent Air Force Cambridge Research Laboratories line parameters listing. Water vapor lines interfere with strong Q-branch absorption features of CCl2F2 in the spectral region near 923 cm−1. The region near 1161 cm−1 is free from water vapor absorption and has the strongest Q-branch feature of CCl2F2. Many laboratory spectra of CCl2F2 were studied and this absorption feature was found to be independent of N2 broadening pressure. No change in the half-width was found as the N2 pressure was varied from 0 to 700 Torr. Furthermore, assuming a Lorentz line shape for this CCl2F2 absorption feature, an intensity of 3.8 × 1018 cm·molecule−1 and a half-width of 0.026 cm−1 were found. Using these parameters, synthetic solar spectra were computed which included the CCl2F2 absorption feature. Results of this computer generation of solar spectra indicate a ground level concentration of 110 parts per trillion of CCl2F2 in our solar spectra.

Novel Approach and Setup for Multi Phase Mixtures Separation and Analysis at Offshore Conditions

2014 ◽  
Vol 625 ◽  
pp. 669-672
Author(s):  
A.A.K. Firas ◽  
Azmi Mohd Shariff ◽  
Lau Kok Keong ◽  
Nurhayati Mellon
Keyword(s):  
Water Vapor ◽  
Binary Mixtures ◽  
Sorption Isotherms ◽  
Dual Phase ◽  
The Novel ◽  
Novel Technique ◽  
Novel Approach ◽  
X Zeolites ◽  
Multi Phase

The precious demand not in the push away and broad off from receive forward developed technology approaches place the hand almost several lacks of warns and in-needed developed technique and techniques for greater than before contract and analysis for several issues, no complimentary and talk to studies within the literature describe the system comes in multi component and dual phase particularly for those that ought to be investigated at offshore conditions, the novel technique and setup has been created for such scope, the recently developed discovered has the flexibility to analyses the sorption isotherms and kinetic for multi component and dual phase mixtures (gas and vapor) at offshore conditions in term of temperature up to 150 oC and pressure up to 150 bar. Additionally to the pretreatment that would be finished to the sorbents used at temperatures up to 400 oC and vacuumed pressure. The primer experiments are done using 13 X zeolites for the sorption of pure CO2 at numerous conditions and binary mixtures (CO2 and CH4) with the existence of water vapor.

scholarly journals Intercomparison of Water Vapor Data Measured with Lidar during IHOP_2002. Part I: Airborne to Ground-Based Lidar Systems and Comparisons with Chilled-Mirror Hygrometer Radiosondes

2007 ◽  
Vol 24 (1) ◽  
pp. 3-21 ◽  
Author(s):  
Andreas Behrendt ◽  
Volker Wulfmeyer ◽  
Hans-Stefan Bauer ◽  
Thorsten Schaberl ◽  
Paolo Di Girolamo ◽  
...  
Keyword(s):  
Water Vapor ◽  
Sea Level ◽  
Great Plains ◽  
Ground Level ◽  
Low Noise ◽  
Lidar Data ◽  
Equal Weight ◽  
Height Range ◽  
Nasa Goddard Space ◽  
Ground Based Lidar

Abstract The water vapor data measured with airborne and ground-based lidar systems during the International H2O Project (IHOP_2002), which took place in the Southern Great Plains during 13 May–25 June 2002 were investigated. So far, the data collected during IHOP_2002 provide the largest set of state-of-the-art water vapor lidar data measured in a field campaign. In this first of two companion papers, intercomparisons between the scanning Raman lidar (SRL) of the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) and two airborne systems are discussed. There are 9 intercomparisons possible between SRL and the differential absorption lidar (DIAL) of Deutsches Zentrum für Luft- und Raumfahrt (DLR), while there are 10 intercomparisons between SRL and the Lidar Atmospheric Sensing Experiment (LASE) of the NASA Langley Research Center. Mean biases of (−0.30 ± 0.25) g kg−1 or −4.3% ± 3.2% for SRL compared to DLR DIAL (DLR DIAL drier) and (0.16 ± 0.31) g kg−1 or 5.3% ± 5.1% for SRL compared to LASE (LASE wetter) in the height range of 1.3–3.8 km above sea level (450–2950 m above ground level at the SRL site) were found. Putting equal weight on the data reliability of the three instruments, these results yield relative bias values of −4.6%, −0.4%, and +5.0% for DLR DIAL, SRL, and LASE, respectively. Furthermore, measurements of the Snow White (SW) chilled-mirror hygrometer radiosonde were compared with lidar data. For the four comparisons possible between SW radiosondes and SRL, an overall bias of (−0.27 ± 0.30) g kg−1 or −3.2% ± 4.5% of SW compared to SRL (SW drier) again for 1.3–3.8 km above sea level was found. Because it is a challenging effort to reach an accuracy of humidity measurements down to the ∼5% level, the overall results are very satisfactory and confirm the high and stable performance of the instruments and the low noise errors of each profile.

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