#geostrophy
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maratimes.bsky.social
I'm teaching geostrophy next week! Maybe I'll use this...
September 27, 2024 at 5:29 PM
fabriceardhuin.bsky.social
🌊 With the FLEX launch (EE8) @esaearth.esa.int , I thought about the EE9 competition and I was discussing with a student about the history of trying to measure ocean currents beyond geostrophy. This paragraph sums up the situation pretty well . Full SKIM report : www.esa.int/Applications...
text: 2.7 Innovation and Advancement of European Earth Observation Capability: Inventing Doppler Oceanography from Space There is no mission flying today that can estimate the TSCV with quasi-global coverage and regular repeat sampling. Instead of ocean topography inferring geostrophic flows from ocean topography, one can measure surface-ocean velocities directly. Based on Envisat C-band synthetic aperture radar (SAR), and more recently Sentinel-1 SAR imagers, ESA (2015b) notes that the capability to measure and interpret ocean geophysical Doppler velocities was a significant achievement of the past decade (Chapron et al., 2005). It was made possible by the massive acquisition of data from Envisat ASAR instrument, followed by the analysis of the geophysical part of the Doppler centroid. In particular it was recognised that ocean waves are the source of a large, about 2 m s-1, ‘wave Doppler’ (UWD) contribution to the geophysical velocity (Chapron et al., 2005; Martin et al., 2016; Nouguier et al., 2018). The feasibility of such measurements was demonstrated at global scales with Envisat Advance SAR (ASAR): the Doppler centroid provides a measurement of a mean ocean- surface velocity, in the line-of-sight, as detected by a radar. Although noisier, this is equivalent to across-track interferometry (ATI, Romeiser et al., 2014). Collard et al., (2008) demonstrated measurements of equatorial currents using Doppler centroid estimates from Envisat ASAR wave-mode. The possibility of using existing C-band SAR systems led to a rapid development of methods for estimating UWD using a wind-based proxy called C-DOP (Mouche et al., 2008, Hansen et al., 2011) and first scientific applications (Rouault et al., 2010). This development was considerably reduced by the end of Envisat in 2012 and the lack of routine SAR data until the launch of Copernicus Sentinel-1 in 2014. Today, acquisitions by Copernicus Sentinel-1 operating in wave mode over the open ocean provide zonal maps of the r… Maps of current component toward the Sentinel 1 satellite : composite over 3 months showing the structure of tropical currents.
September 9, 2026 at 4:33 PM
mathna-bot.bsky.social
arXiv:2505.17044v1 Announce Type: new
Abstract: We derive the global model of thermal quasi-geostrophy on the sphere via asymptotic expansion of the thermal rotating shallow water equations. The model does not rely on the asymptotic expansion of the [1/5 of https://arxiv.org/abs/2505.17044v1]
May 26, 2025 at 6:04 AM
murtuguddeacademy.bsky.social
Chapter 7 is the heart of the book. We learn large-scale balances like Geostrophy & cyclostrophy. Compressible & incompressible fluids give us really amazing insights into oceanic and atmospheric circulations including the Taylor-Proudman theorem & the Taylor column.

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OAD - Chapter 7 - Balanced Flow - YouTube
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March 15, 2025 at 3:36 PM
murtuguddeacademy.bsky.social
Chapter 3 of Tropical Dynamics covers all the fundamental processes of ocean-atmosphere circulations and large-scale balances. #climate #climatedynamics #atmosphere #oceans #tropics #oceancurrents #winds #geostrophy #thermodynamics

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TC - Chapter 3 - Fundamental Processes of the Tropical Atmospheric Dynamics - YouTube
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December 23, 2024 at 5:44 PM