Publications

Isern-Fontanet, J.; Hascoet, E. (2014). Diagnosis of high-resolution upper ocean dynamics from noisy sea surface temperatures. JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS, 119(1), 121-132.

Abstract
The noise present in infrared satellite measurements of sea surface temperature (SST) hampers the use of surface quasi-geostrophic (SQG) equations to diagnose ocean dynamics at high resolutions. Here we propose a methodology to reduce the contribution of noise when diagnosing surface vorticity, divergence, and vertical velocity from SST able to retain the dynamics at scales of a few kilometers. It is based on the use of denoising techniques with curvelets as basis functions and the application of a selective low-pass filters to improve the reconstruction of surface upwelling/downwelling patterns. First, it is tested using direct numerical simulations of SQG turbulence and then applied to diagnose low-frequency vertical velocity patterns from real MODIS (Moderate Resolution Imaging Spectroradiometer) images. The methodology here presented, which is not tied to the validity of SQG equations nor to the use of SST, is quite general and can be applied to a wide range of measurements and dynamical frameworks.Key Points Noise present in IR sensors limits its use to diagnose high-resolution dynamics It provides a method to estimate vertical velocities from real satellite data The method can be used to remove noise from other satellite measurements

DOI:
10.1002/2013JC009176

ISSN:
2169-9275; 2169-9291