Author: Jeffrey Ryan Taylor
Publisher:
ISBN: 9780494581025
Category : Physics Theses
Languages : en
Pages : 542
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Book Description
A high-resolution infrared Fourier Transform Spectrometer (FTS) has been operational at the Toronto Atmospheric Observatory (TAO) since May 2002. An optimal estimation retrieval technique is used to analyse the observed spectra and provide regular total and partial column measurements of trace gases in the troposphere and stratosphere as part of the Network for the Detection of Atmospheric Composition Change. The quality of these results were assessed through two ground-based validation campaigns, comparisons with three satellite instruments, and comparison with a three-dimensional chemical transport model.The two ground-based campaigns involved two lower-resolution FTS instruments: the University of Toronto FTS and the Portable Atmospheric Research Interferometric Spectrometer for the Infrared. The first campaign took place over the course of four months and is the longest side-by-side intercomparison of ground-based FTS instruments, to date. The second campaign was more focused and involved all three instruments measuring over a two-week period. Simultaneous measurements of O3, HCl, N2O, and CH4 were recorded and average total column differences were all
Author: Aldona Wiacek
Publisher:
ISBN: 9780494220177
Category : Physics Theses
Languages : en
Pages : 233
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Book Description
A systematic study showed that the effect of several different layering schemes (implicit retrieval constraints) on the retrieved vertical profile is less than 5% for N2O and HF, and less than 2% for NO, NO 2, CH4 and HCl; however, retrieved profiles of H2O showed differences up to 13% when the layering scheme was varied. A maximum tropospheric layer thickness of 0.8 km is inferred for accurate H2O retrievals. A new high-resolution (0.004 cm-1) research-grade Fourier transform spectrometer was installed at the University of Toronto Atmospheric Observatory (TAO), and commissioned in October 2001. TAO fills a coverage gap in North America in the Network for the Detection of Atmospheric Composition Change (NDACC), and was accepted as a Complementary Station in March 2004 as a direct result of work presented in this thesis. Finally, the usefulness of Fourier Transform InfraRed (FTIR) observations for studying different regions of the atmosphere was demonstrated by (1) documenting a limited sensitivity of ground-based measurements to mesospheric-lower thermospheric concentrations of NO, (2) correlating anomalously high stratospheric HCl, HF and O3 concentrations derived at TAO with the passage of a polar air filament above Toronto, and (3) showing very good agreement between monthly mean abundances of tropospheric CO between January 2002--September 2003 and spatially coincident MOPITT satellite measurements. Trace gas concentrations are derived using an existing Optimal Estimation Method (OEM) retrieval algorithm implemented at TAO as part of this work. A set of prior constraints necessary for retrievals of vertical profiles of trace gases using the OEM approach was optimized, and includes a priori volume mixing ratio profiles suited to TAO's location, and the prior and measurement noise covariances. A three-year time series of O3, NO. NO2, HCl, HF, N2O and CH4 (exhibiting the known seasonal cycles) was submitted to the NDACC database for long-terra monitoring, trend detection, and satellite validation purposes. A quantitative retrieval characterization was performed whereby the averaging kernels, weighting functions, measurement, smoothing and temperature error covariances of the retrievals of these seven gases were calculated. The degrees of freedom for signal ranged from 1.10 for NO2 to 4.12 for N2O.
Author: Cynthia Whaley
Publisher:
ISBN:
Category :
Languages : en
Pages : 258
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Book Description
Author: Nicholas David Causier Allen
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Author: A. F. Bouwman
Publisher: Elsevier Science Limited
ISBN: 9780444829344
Category : Science
Languages : en
Pages : 362
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Book Description
This book should appeal to students and scientists working in the field of atmospheric chemistry, micrometeorology, soil science, ecology, physical geography, marine and freshwater sciences, monitoring of land use and vegetation, database development, remote sensing, and all those studying the changing physical and chemical climate of the Earth.
Author: Joseph C. Casas
Publisher:
ISBN:
Category : Atmosphere
Languages : en
Pages : 4
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Book Description
Author: Earl C. Kindle
Publisher:
ISBN:
Category : Air
Languages : en
Pages : 166
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Book Description
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 1572
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Book Description
Author: Michael Gerardus Maria Roemer
Publisher:
ISBN: 9789054110972
Category :
Languages : en
Pages : 58
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Book Description
Author: Ghenadii Korotcenkov
Publisher: CRC Press
ISBN: 1351400649
Category : Science
Languages : en
Pages : 598
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Book Description
The first volume of The Handbook of Humidity Measurement focuses on the review of devices based on optical principles of measurement such as optical UV, fluorescence hygrometers, optical and fiber-optic sensors of various types. Numerous methods for monitoring the atmosphere have been developed in recent years, based on measuring the absorption of electromagnetic field in different spectral ranges. These methods, covering the optical (FTIR and Lidar techniques), as well as a microwave and THz ranges are discussed in detail in this volume. The role of humidity-sensitive materials in optical and fiber-optic sensors is also detailed. This volume describes the reasons for controlling the humidity, features of water and water vapors, and units used for humidity measurement.
