24-113 Short Waves Properties
Il y a 2 mois
Doctorat, 36 mois
- Temps plein
- Aucune expérience exigée
- Maitrise, IEP, IUP, Bac+4
- Oceanography
**Mission**:
ODYSEA mission concept is based on Radar Doppler scatterometry. It measures the mean velocity of ocean surface at high incidence over a few kilometers. The measured Doppler velocity not only includes surface currents, but also the mean wave velocity, which is subtracted from the measurement with an ad hoc model. Since the backscattering regime (Bragg) at high incidence angle involves only small scale waves (between 5mm and 40cm), the celerity model accuracy is a key for the current retrieval performance.
The geometry and kinematics of the sea surface on small scales are currently very poorly understood for scales of less than one meter. Numerous observations, particularly in the laboratory, show strong spatial variability in the amplitude of centimeter waves in the presence of longer waves, especially in light winds. This non-homogeneity of centimeter waves is likely to explain differences of the order of 20 cm/s between Doppler velocity observations and numerical simulations assuming a homogeneous distribution of short waves. This non-homogeneity may also have consequences for other properties of the wave field, such as the intensity of radiated acoustic noise.
The aim of the proposed thesis is to analyze the properties of centimeter waves and propose a parameterization of their variability in the presence of longer waves. This parametrization could be confronted with various measurements of short-wave properties: Doppler radar measurements (ASIT data, DopplerScatt S-MODE, HOMARDS).
Also polarimetric video recordings of the sea surface acquired during the SUMOS (Bay of Biscay) and SWOT-ASIT (east coast of the USA) campaigns show a short-wave signature and should make it possible to quantify short-wave heterogeneities and link their modulation to intermediate wave properties in order to propose a physical model. An additional campaign in 2025 could provide additional data
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**Profil**:
master in oceanography
**Laboratoire**:
LOPS
**Message from PhD Team**:
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