Identification of snowfall microphysical processes from Eulerian vertical gradients of polarimetric radar variables

Polarimetric radar systems are commonly used to study the microphysics of precipitation. While they offer continuous measurements with a large spatial coverage, retrieving information about the microphysical processes that govern the evolution of snowfall from the polarimetric signal is challenging....

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Published in:Atmospheric Measurement Techniques
Main Authors: Planat, Noemie, Gehring, Josue, Vignon, Etienne, Berne, Alexis
Format: Text
Language:unknown
Published: Gottingen, COPERNICUS GESELLSCHAFT MBH 2021
Subjects:
Online Access:https://doi.org/10.5194/amt-14-4543-2021
https://infoscience.epfl.ch/record/287389/files/amt-14-4543-2021.pdf
http://infoscience.epfl.ch/record/287389
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spelling ftinfoscience:oai:infoscience.epfl.ch:287389 2023-05-15T13:04:21+02:00 Identification of snowfall microphysical processes from Eulerian vertical gradients of polarimetric radar variables Planat, Noemie Gehring, Josue Vignon, Etienne Berne, Alexis 2021-07-17T00:34:39Z https://doi.org/10.5194/amt-14-4543-2021 https://infoscience.epfl.ch/record/287389/files/amt-14-4543-2021.pdf http://infoscience.epfl.ch/record/287389 unknown Gottingen, COPERNICUS GESELLSCHAFT MBH isi:000664205900003 doi:10.5194/amt-14-4543-2021 https://infoscience.epfl.ch/record/287389/files/amt-14-4543-2021.pdf http://infoscience.epfl.ch/record/287389 http://infoscience.epfl.ch/record/287389 Text 2021 ftinfoscience https://doi.org/10.5194/amt-14-4543-2021 2023-02-13T23:05:59Z Polarimetric radar systems are commonly used to study the microphysics of precipitation. While they offer continuous measurements with a large spatial coverage, retrieving information about the microphysical processes that govern the evolution of snowfall from the polarimetric signal is challenging. The present study develops a new method, called process identification based on vertical gradient signs (PIVSs), to spatially identify the occurrence of the main microphysical processes (aggregation and riming, crystal growth by vapor deposition and sublimation) in snowfall from dual-polarization Doppler radar scans. We first derive an analytical framework to assess in which meteorological conditions the local vertical gradients of radar variables reliably inform about microphysical processes. In such conditions, we then identify regions dominated by (i) vapor deposition, (ii) aggregation and riming and (iii) snowflake sublimation and possibly snowflake breakup, based on the sign of the local vertical gradients of the reflectivity Z(H) and the differential reflectivity Z(DR). The method is then applied to data from two frontal snowfall events, namely one in coastal Adelie Land, Antarctica, and one in the Taebaek Mountains in South Korea. The validity of the method is assessed by comparing its outcome with snowflake observations, using a multi-angle snowflake camera, and with the output of a hydrometeor classification, based on polarimetric radar signal. The application of the method further makes it possible to better characterize and understand how snowfall forms, grows and decays in two different geographical and meteorological contexts. In particular, we are able to automatically derive and discuss the altitude and thickness of the layers where each process prevails for both case studies. We infer some microphysical characteristics in terms of radar variables from statistical analysis of the method output (e.g., Z(H) and Z(DR) distribution for each process). We, finally, highlight the potential for extensive ... Text Adelie Land Antarc* Antarctica EPFL Infoscience (Ecole Polytechnique Fédérale Lausanne) Atmospheric Measurement Techniques 14 6 4543 4564
institution Open Polar
collection EPFL Infoscience (Ecole Polytechnique Fédérale Lausanne)
op_collection_id ftinfoscience
language unknown
description Polarimetric radar systems are commonly used to study the microphysics of precipitation. While they offer continuous measurements with a large spatial coverage, retrieving information about the microphysical processes that govern the evolution of snowfall from the polarimetric signal is challenging. The present study develops a new method, called process identification based on vertical gradient signs (PIVSs), to spatially identify the occurrence of the main microphysical processes (aggregation and riming, crystal growth by vapor deposition and sublimation) in snowfall from dual-polarization Doppler radar scans. We first derive an analytical framework to assess in which meteorological conditions the local vertical gradients of radar variables reliably inform about microphysical processes. In such conditions, we then identify regions dominated by (i) vapor deposition, (ii) aggregation and riming and (iii) snowflake sublimation and possibly snowflake breakup, based on the sign of the local vertical gradients of the reflectivity Z(H) and the differential reflectivity Z(DR). The method is then applied to data from two frontal snowfall events, namely one in coastal Adelie Land, Antarctica, and one in the Taebaek Mountains in South Korea. The validity of the method is assessed by comparing its outcome with snowflake observations, using a multi-angle snowflake camera, and with the output of a hydrometeor classification, based on polarimetric radar signal. The application of the method further makes it possible to better characterize and understand how snowfall forms, grows and decays in two different geographical and meteorological contexts. In particular, we are able to automatically derive and discuss the altitude and thickness of the layers where each process prevails for both case studies. We infer some microphysical characteristics in terms of radar variables from statistical analysis of the method output (e.g., Z(H) and Z(DR) distribution for each process). We, finally, highlight the potential for extensive ...
format Text
author Planat, Noemie
Gehring, Josue
Vignon, Etienne
Berne, Alexis
spellingShingle Planat, Noemie
Gehring, Josue
Vignon, Etienne
Berne, Alexis
Identification of snowfall microphysical processes from Eulerian vertical gradients of polarimetric radar variables
author_facet Planat, Noemie
Gehring, Josue
Vignon, Etienne
Berne, Alexis
author_sort Planat, Noemie
title Identification of snowfall microphysical processes from Eulerian vertical gradients of polarimetric radar variables
title_short Identification of snowfall microphysical processes from Eulerian vertical gradients of polarimetric radar variables
title_full Identification of snowfall microphysical processes from Eulerian vertical gradients of polarimetric radar variables
title_fullStr Identification of snowfall microphysical processes from Eulerian vertical gradients of polarimetric radar variables
title_full_unstemmed Identification of snowfall microphysical processes from Eulerian vertical gradients of polarimetric radar variables
title_sort identification of snowfall microphysical processes from eulerian vertical gradients of polarimetric radar variables
publisher Gottingen, COPERNICUS GESELLSCHAFT MBH
publishDate 2021
url https://doi.org/10.5194/amt-14-4543-2021
https://infoscience.epfl.ch/record/287389/files/amt-14-4543-2021.pdf
http://infoscience.epfl.ch/record/287389
genre Adelie Land
Antarc*
Antarctica
genre_facet Adelie Land
Antarc*
Antarctica
op_source http://infoscience.epfl.ch/record/287389
op_relation isi:000664205900003
doi:10.5194/amt-14-4543-2021
https://infoscience.epfl.ch/record/287389/files/amt-14-4543-2021.pdf
http://infoscience.epfl.ch/record/287389
op_doi https://doi.org/10.5194/amt-14-4543-2021
container_title Atmospheric Measurement Techniques
container_volume 14
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