Download or read book Atmospheric Water Vapour Differential Absorption Measurements with an Infra red Sounder written by P. W. Baker and published by . This book was released on 1982 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: The atmospheric differential absorption by water vapour between tow CO2 laser transmission lines has been measured up to heights of 1.5 km with a groundbased sounder system. Water vapour profiles, some containing distinct layers, have been estimated from long and short pulse soundings, and compared with radiosonde measurements. Strongly scattering aerosol layers, often associated with temperature inversions, cause severe distortion of the long pulse differential absorption profiles, indicating the necessity of using a short pulse technique. This technique shows potential usefulness for the remote measurement of radio refractive index layers in the atmosphere. (Author).

Download or read book An Outline for the RTNEPH Infrared Atmospheric Water Vapor Attenuation Study written by Robert Paul D'Entremont and published by . This book was released on 1989 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Real-Time Nephanalysis (RTNE PH) generates real-time global analysis of cloud extent, base, height, and type. The RTNE PH makes extensive use of satellite data that are measured in the 10-12 micron infrared (IR) window for thermal mapping of clouds and the earth's surface both day and night. Water vapor absorption effects are significant in such data, especially for high viewing angles and tropical atmospheres where water vapor concentrations are generally high. Water vapor attenuates the emitted ground radiance, reducing its magnitude and with it the apparent temperature of the surface being viewed. Currently, the RTNEPH takes into account such attenuation losses using lookup tables that are functions of viewing geometry, time of day, type of background, and the like. However, these corrections have limited value and leave room for significant improvement. This report outlines and presents two new techniques that are expected to enhance the attenuation correction capabilities of the RTNEPH, multivariate polynomial regression (the Weinreb technique) and the correlated K method.

Download or read book Monitoring Atmospheric Water Vapour written by Niklaus Kämpfer and published by Springer Science & Business Media. This book was released on 2012-09-11 with total page 325 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atmospheric water plays a key role in climate. Water vapour is the most important greenhouse gas and its condensed forms exert a profound influence on both incoming solar and outgoing infrared radiation. Unfortunately, accurate, height-resolved global-scale measurements of atmospheric humidity are difficult to obtain. The change in concentration of five orders of magnitude form the ground to the stratosphere means there is no standard instrument that will measure everywhere. This has led to different measuring techniques, all with strengths and weaknesses. This book assesses all presently available techniques that are used in monitoring networks. Special weight is given to presenting the different technical concepts, the accuracy of different sensor types, addresses calibration issues and retrieval aspects.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Atmospheric Pre corrected Differential Absorption Techniques to Retrieve Columnar Water Vapor written by and published by . This book was released on 1996 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Water vapor is one of the main forces for weather development as well as for mesoscale air transport processes. The monitoring of water vapor is therefore an important aim in remote sensing of the atmosphere. Current operational systems for water vapor detection use primarily the emission in the thermal infrared (AVHRR, GOES, ATSR, Meteosat) or in the microwave radiation bands (DMSP). The disadvantage of current satellite systems is either a coarse spatial (horizontal) resolution ranging from one to tens of kilometers or a limited insight into the lower atmosphere. Imaging spectrometry on the other hand measures total column water vapor contents at a high spatial horizontal resolution and has therefore the potential of filling these gaps. The sensors of the AVIRIS instrument are capable of acquiring hyperspectral data in 224 bands located in the visible and near infrared at 10 run resolution. This data includes information on constituents of the earth's surface as well as of the atmosphere. The optical measurement of water vapor can be performed using sensor channels located in bands or lines of the absorption spectrum. The AVIRIS sensor has been used to retrieve water vapor and with less accuracy carbon dioxide, oxygen and ozone. To retrieve the water vapor amount, the so called differential absorption technique has been applied. The goal of this technique is to eliminate background factors by taking a ratio between channels within the absorption band and others besides the band. Various rationing methods on the basis of different channels and calculation techniques were developed. The influence of a trace gas of interest on the radiance at the sensor level is usually simulated by using radiative transfer codes. In this study, spectral transmittance and radiance are calculated by MODTRAN3 simulations with the new DISORT option. This work testS the best performing differential absorption techniques for imaging spectrometry of tropospheric water vapor.

Download or read book Atmospheric Infrared Sounder AIRS written by and published by . This book was released on 1990 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Atmospheric Water Vapour Sensing by Means of Differential Absorption Spectrometry Using Solar and Lunar Radiation written by Stefan Walter Münch and published by . This book was released on 2013 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nu averaged Infrared Absorption Coefficients of Water Vapor written by R. F. Calfee and published by . This book was released on 1973 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report the quantitative absorption coefficients of water vapor in a format suitable for calculation of water vapor absorption spectra characterized by instrumental bandpasses of 1 cm−1 or greater in the 670 to 1450 cm−1 region. The coefficients are derived from individual line parameters of H2O and represent a useful way of reducing line parameter data to a practical volume of information for 1 cm−1 resolution spectra of the troposphere. Transmission spectra for three water vapor concentrations show typical applications of the absorption coefficient tables. The application of the data is restricted to conditions within 10% of 1 atmosphere pressure and a temperature of 296 K if a transmission accuracy of 2% is to be maintained.

Download or read book Differential Absorption Lidars for Remote Sensing of Atmospheric Pressure and Temperature Profiles written by and published by . This book was released on 1995 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Infrared Absorption by Carbon Dioxide Water Vapor and Minor Atmospheric Constituents written by and published by . This book was released on 1962 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Infrared Continuum Absorption by Atmospheric Water Vapor in the 8 12 Micrometer Window written by and published by . This book was released on 1976 with total page 29 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have carried out a detailed analysis of several long-path-length transmission measurements in the 8 to 12 micrometer atmospheric window in order to determine the extinction coefficient due to the water vapor continuum. Our results indicate that three modifications to the current LOWTRAN atmospheric transmission model are required. The first two corrections are an improved fit to the pure water vapor continuum absorption coefficient and the elimination of the atmospheric broadened continuum term. Finally, and most critically, a strong measured temperature dependence must be included in the water vapor continuum absorption coefficient. For path lengths ranging from 10 to 50 km, failure to incorporate these corrections can lead to errors in the computed transmission ranging from factors of 2 to more than 10,000.

Download or read book Infrared Water Vapor Continuum Absorption written by Hugh R. Carlon and published by . This book was released on 1989 with total page 33 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Measurements of the Atmospheric Water Vapour Pressure in Shallow Radiation Fogs by Infra red Hygrometry written by M. Clay and published by . This book was released on 1980 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Anomalous Absorption by Atmospheric Water Vapor and Stabilized Water Fogs in the Infrared and CM Wave Regions written by Hugh R. Carlon and published by . This book was released on 1989 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: Measurements of anomalous or excessive absorption by atmospheric water vapor, i.e., absorption in excess of water monomer absorption and droplet scattering predictions, are analyzed for the infrared and 5-17/cm regions. Both fair weather and fog data are considered. It is found that observations in both spectral regions can be explained by clustering (hydrogen bonding) of approx. .001 of vapor molecules. The development leads to several tentative conclusions: 1) equilibrium cluster populations (and maximum absorption) are only attained for vapor in contact with liquid water; 2) the clusters are formed by evaporation, are large, and cannot be modeled by Boltzmann statistics; 3) cluster modes can account for unexplained spectral features at 5-17/cm; 4) excessive absorption both in the infrared and 5-17/cm regions probably can be explained by the same cluster species. In the appendix, the visible and infrared optical properties of evaporation stabilized water fogs also are considered. Evaporation of artificial water fogs can be retarded by the application of coatings of long-chain fatty alcohols to the droplets during generation. Measurements are described, and droplet diameters and mass extinction coefficients are reported for water fogs coated with cetyl alcohol (1-hexadecanol) from a commercial generator. (aw).

Download or read book The Composition of Atmospheric Water Vapor and Anomalous Absorption of Far Infrared Radiation written by Ronald Arthur Bohlander and published by . This book was released on 1972 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Observational Analysis of the Dimensional Characteristics of Global Mass Mixed Ratio Water Vapor Via the Atmospheric Infrared Sounder written by Barry Scott Martinez and published by . This book was released on 2018 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: Water vapor plays a key role in the atmospheric hydrological cycle by allowing winds to move water around Earth and by providing the water source for the formation of clouds and precipitation. This study utilizes the complete 14-year observational data record of the Atmospheric Infrared Sounder (AIRS), the first spaceborne instrument specifically designed to measure changes in the amount of atmospheric water vapor and other greenhouse gases. This study is of an observational analysis only into the characteristic into the vertical distribution and dimensional examination of precipitable water vapor through the 925mb -- 300mb levels of the atmosphere.

Download or read book Validation of the Far infrared Foreign broadened Water Vapour Continuum from Airborne Field Campaign Measurements written by Ralph Beeby and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes spectrally-resolved radiance measurements, recorded using the Imperial College-built Tropospheric Airborne Fourier Transform Spectrometer (TAFTS), to validate the current parameterisation of the far-infrared foreign- broadened continuum of atmospheric water vapour in line-by-line radiative transfer models. The current parameterisation is not based on measurement through the centre of the far-IR spectral region, but is constructed by interpolation from measurements either side of the band. Accurate knowledge of this parameterisation is essential as the far-IR contribution to the planetary outgoing longwave radiation (OLR) is significant. The research takes the form of a radiative closure study, comparing the radiance measurements with simulated radiances modelled using the measured atmospheric state (temperature, humidity) profile as input. The profile information was recorded, alongside the radiance measurements, aboard the UK Met Office / FAAM (Facility for Airborne Atmospheric Measurements) BAe-146 research aircraft, during the first of two field campaigns as part of the CAVIAR (Continuum Absorption in the Visible and Infrared and its Atmospheric Relevance) project. This thesis provides an overview of the relevant atmospheric physics and Fourier Transform Spectroscopy, including a description of TAFTS; the construction of the atmospheric profiles from the various in-situ, radiosonde and model datasets; the calibration of the radiances measured by TAFTS and derivation of the foreign- broadened water vapour continuum between 114- 540 cm-1 within the framework of the line-by-line radiative transfer model (LBLRTM v12.0). The resulting continuum is compared to other relevant recent studies. The measurements from this study suggest an increase in continuum strength up to 11 % at 238.6 cm -1, decreasing steadily to a reduction of 55 % at 114 cm -1 and 54 % at 513 cm-1. However, the uncertainties in these measurements are considerable, and might equally suggest an increase in continuum strength.