Information content on hydrometeors from millimeter and sub-millimeter wavelengthsReport as inadecuate

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Météo-France-CNRS, Toulouse .Mahfouf, Jean-François Météo-France-CNRS, Toulouse.Milz, Mathias Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. IRV.ORCID iD: 0000-0002-4478-2185Mendrok, Jana Chalmers University of Technology, Gothenburg, Sweden.Buehler, Stefan A. University of Hamburg, Hamburg.Brath, Manfred University of Hamburg, Hamburg .Show others and affiliations Number of Authors: 8 2017 (English)In: Tellus. Series A, Dynamic meteorology and oceanography, ISSN 0280-6495, E-ISSN 1600-0870, Vol. 69, no 1, 1271562Article in journal (Refereed) Published

Abstract [en] : This study examines the information content on hydrometeors that could be provided by a future HYperspectralMicrowave Sensor (HYMS) with frequencies ranging from 6.9 to 874 GHz (millimeter and sub-millimeter regions). Through optimal estimation theory the information content is expressed quantitatively in terms of degrees of freedom for signal (DFS). For that purpose the Atmospheric Radiative Transfer Simulator (ARTS) and its Jacobians are used with a set of 25 cloudy and precipitating profiles and their associated errors from the European Centre for Medium-range Weather Forecasting (ECMWF) global numerical weather prediction model.In agreement with previous studies it is shown that frequencies between 10 and 40 GHz are the most informative ones for liquid and rain water contents. Similarly, the absorption band at 118 GHz contains significant information on liquid precipitation. A set of new window channels (15.37-, 40.25-, 101-GHz) could provide additional information on the liquid phase. The most informative channels on cloud icewater are the window channels at 664 and 874GHz and thewater vapour absorption bands at 325 and 448 GHz. Regarding snow water contents, the channels having the largest DFS values are located inwindow regions (150-, 251-, 157-, 101-GHz). However it is necessary to consider 90 channels in order to represent 90% of the DFS. The added value of HYMS has been assessed against current Special Sensor Microwave Imager/Sounder (SSMI/S) onboard the Defense Meteorological Satellite Program (DMSP) and future (Microwave Imager/Ice Cloud Imager (MWI/ICI) onboard European Polar orbiting Satellite – Second Generation (EPS-SG)) microwave sensors. It appears that with a set of 276 channels the information content on hydrometeors would be significantly enhanced: the DFS increases by 1.7 against MWI/ICI and by 3 against SSMI/S. A number of tests have been performed to examine the robustness of the above results. The most informative channels on solid hydrometeors remain the same over land and over ocean surfaces. On the other hand, the database is not large enough to produce robust results over land surfaces for liquid hydrometeors. The sensitivity of the results to the microphysical properties of frozen hydrometeors has been investigated. It appears that a change in size distribution and scattering properties can move the large information content of the channels at 664 and 874 GHz from cloud ice to solid precipitation.

Place, publisher, year, edition, pages: 2017. Vol. 69, no 1, 1271562

Keyword [en] : Information Content, clouds, precipitaion, microwave radiation

National Category : Meteorology and Atmospheric Sciences Aerospace Engineering

Research subject: Atmospheric science

Identifiers: URN: urn:nbn:se:ltu:diva-61623DOI: 10.1080/16000870.2016.1271562ISI: 000395918400001Scopus ID: 2-s2.0-85015235782OAI: diva2:1068327

Note: Validerad; 2017; Nivå 2; 2017-01-31 (andbra)Available from: 2017-01-25 Created: 2017-01-25 Last updated: 2017-03-31Bibliographically approved

Author: Birman, Camille


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