Analyse des propriétés dimensionnelles et massiques des cristaux de glace pour l’étude des processus microphysiques dans les systèmes convectifs à méso-échelle

Abstract : The detailed characterization of ice cloud microphysics is key to understand their role in theEarth’s hydrological cycle and radiation budget. The developement of atmospheric models and remote sensingalgorithms relies on parametrisations derived from in situ measurements. These measurements are also usedby the aviation industry to handle the problem of ice crystal icing. This PhD work presents an analysis of themass and size properties of ice crystals observed in high ice water content areas embedded in tropical mesoscaleconvective systems (MCS) during two airborne field campaigns of the HAIC-HIWC international project.A new approach is developped to derive mass-size relationships (m - D) from size distributions and icewater contents. The retrieval is formulated as an inverse problem which waives the power law constraint, aclassical assumption that proves to be an oversimplification when applied to heterogeneous populations of iceparticules typical of MCS anvils.The horizontal variability of size distributions and the aging of MCS anvils is described in terms of microphysicalprocesses. The importance of the aggregation growth process is emphasized as it efficiently removessmall ice particles brought into the upper troposphere by deep convection and significantly contributes to theformation of large agregates, precusor of the stratiform precipitations. The analysis of mass properties revealsthat distinctive microphysical regimes may be identified from the m-D relationship retrieved in various conditions.It paves the way toward a statistical model of the effective density of ice particles as a function of environmentalparameters.
Document type :
Theses
Complete list of metadatas

Cited literature [280 references]  Display  Hide  Download

https://tel.archives-ouvertes.fr/tel-02275192
Contributor : Abes Star <>
Submitted on : Monday, September 2, 2019 - 4:20:08 PM
Last modification on : Tuesday, September 3, 2019 - 1:19:54 AM

File

2019CLFAC007_COUTRIS.pdf
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-02275192, version 2

Collections

Citation

Pierre Coutris. Analyse des propriétés dimensionnelles et massiques des cristaux de glace pour l’étude des processus microphysiques dans les systèmes convectifs à méso-échelle. Sciences de la Terre. Université Clermont Auvergne, 2019. Français. ⟨NNT : 2019CLFAC007⟩. ⟨tel-02275192v2⟩

Share

Metrics

Record views

99

Files downloads

42