VARiational Analysis of Nonhydrostatic Dynamics using short-time Delayed microwave measurements, VARAND 2
Abstract
Deep convective clouds play a central role in the Earth water and energy cycles, yet their rapid vertical development remains difficult to characterize. The C2OMODO mission relies on a tandem of two passive microwave radiometers flying sequentially with a time separation ranging from 45 to 135 s. This configuration enables the estimation of shorttime brightness temperature differences that informs on convective dynamics. In this study,we introduce VARAND2, a one-dimensional variational method that exploits multitemporal passive microwave observations like those provided by C2OMODO to retrieve key dynamical properties of deep convection. VARAND2 retrieves the vertical profile and short-time evolution of the IceWater Content (IWC), as well as a parametrized vertical profile of air vertical velocity (wair), characterized by its maximum amplitude (wmax) and the corresponding altitude (zmax). These quantities are estimated through a dynamic observation operator that links short-time variations of IWC and brightness temperature via an embedded vertical advection scheme. Applied to simulated C2OMODO observations for a tropical convective case, VARAND2 provides consistent reconstructions of wair, with coefficients of determination (r 2) of 0.71 and 0.72 for the retrieval of wmax and zmax, respectively. These results highlight the potential of multi-temporal passive microwave observations to improve the characterization of deep convective updrafts and their representation in weather and climate models.
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BibTeX
@article{lefebvre2026variational,
title = {{VARiational Analysis of Nonhydrostatic Dynamics using short-time Delayed microwave measurements, VARAND 2}},
author = {Thomas Lefebvre and Hélène Brogniez and Laura Hermozo and Frédéric Chevallier},
journal = {Atmospheric Science Letters},
year = {2026},
month = oct,
doi = {10.1002/asl2.70063},
url = {https://hal.science/hal-05766718v2},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - VARiational Analysis of Nonhydrostatic Dynamics using short-time Delayed microwave measurements, VARAND 2
AU - Thomas Lefebvre
AU - Hélène Brogniez
AU - Laura Hermozo
AU - Frédéric Chevallier
PY - 2026
DA - 2026/10/23
JO - Atmospheric Science Letters
DO - 10.1002/asl2.70063
UR - https://hal.science/hal-05766718v2
AB - Deep convective clouds play a central role in the Earth water and energy cycles, yet their rapid vertical development remains difficult to characterize. The C2OMODO mission relies on a tandem of two passive microwave radiometers flying sequentially with a time separation ranging from 45 to 135 s. This configuration enables the estimation of shorttime brightness temperature differences that informs on convective dynamics. In this study,we introduce VARAND2, a one-dimensional variational method that exploits multitemporal passive microwave observations like those provided by C2OMODO to retrieve key dynamical properties of deep convection. VARAND2 retrieves the vertical profile and short-time evolution of the IceWater Content (IWC), as well as a parametrized vertical profile of air vertical velocity (wair), characterized by its maximum amplitude (wmax) and the corresponding altitude (zmax). These quantities are estimated through a dynamic observation operator that links short-time variations of IWC and brightness temperature via an embedded vertical advection scheme. Applied to simulated C2OMODO observations for a tropical convective case, VARAND2 provides consistent reconstructions of wair, with coefficients of determination (r 2) of 0.71 and 0.72 for the retrieval of wmax and zmax, respectively. These results highlight the potential of multi-temporal passive microwave observations to improve the characterization of deep convective updrafts and their representation in weather and climate models.
SN - 1530-261X
SN - 1530-261X
ER -