1-1 AirSWOT January 2013
AirSWOT
French Oceanographic Campaigns
R. Morrow, LEGOS
GoLSWOT A working group for the
AirSWOT experiment over the Gulf of Lion
PI: Francesco d'Ovidio LOCAN-IPSL, Paris, France Co-PI: Francesco Nencioli, MIO, Marseille, France
1-2 AirSWOT January 2013
AirSWOT French ocean experiments
Science Objectives • Make SSH spectrum measurement in different regions • Determine Eulerian and Lagrangian structures and temporal
decorrelation times (min campaign 15 days) • Ancillary satellite and in-situ data will allow verification of relationship
between SSH, slope and currents
Measurement Objectives • Which key parameters of the SWOT error budget can we investigate
with AirSWOT? • What complementary observations do we need to separate the signal
and the AirSWOT errors ? Eg wind, wave, surface rugosity, optical images, HR SST or ocean colour ?
=> Need a clear idea of the error budget for AirSWOT vs error budget for SWOT – what priorities are we testing with each FR & US experiment?
1-3 AirSWOT January 2013
AirSWOT NW Mediterranean Sea – Spring 2014 – why?
1-4 AirSWOT January 2013
AirSWOT Numerical simulations
1-5 AirSWOT January 2013
AirSWOT Standard SSH maps
Smaller structures not represented in standard SSH maps
Regional HR mapping of altimetry
data being developed
1-6 AirSWOT January 2013
AirSWOT LATEX experiment
1-7 AirSWOT January 2013
AirSWOT GoLSWOT
1-8 AirSWOT January 2013
AirSWOT Proposed Data Collection Site NW Med – Spring 2014 ?
AltiKa/Envisat Jason-2
Weather Buoy
1-9 AirSWOT January 2013
AirSWOT Regular ocean sampling
MOOSE : monthly glider lines, HF Radar at Leucate (currents & waves), coastal buoy time series T,S, chl; meteo-buoy & super-site
1-10 AirSWOT January 2013
AirSWOT Additional in-situ observations
• Compare AirSWOT derived velocities with in-situ measurements (ADCP + Drifter clusters)
• Investigate subsurface/vertical dynamics (ADCP + MVP sections)
• Calval from GPS buoys, or surface flux buoys • 2 Gliders in formation
• Deployment of coastal HF radar or HF “ground wave” radar for detecting surface waves & currents for 2014 … B. Chapron
• Analysis of sub-mesoscale/frontal dynamics • Adaptive sampling strategy effective • Costs are limited (ship-time + Lagrangian drifters) • Option for “minimal” campaign in 2014 or “multi-
disciplinary” campaign in 2015-16
1-11 AirSWOT January 2013
AirSWOT Other satellite observations
• Nadir altimetry : colocate with Jason-2 track 146 but also use Jason-1, CR2, SARAL in the region
• TanDEM-X could give access to the DEM for hydrology and the alongtrack high-resolution ocean currents, as validation data for the AirSWOT campaigns.
• Radarsat-2 data may be available via request from BreTel (local acquisition Vigisat).
• Cryosat-2 is in SAR mode for NW Med – could also request InSAR mode ?
1-12 AirSWOT January 2013
AirSWOT Operational ocean models
• 1 km Symphony model of NW Med operating in operational NRT mode for Hymex 2012+
• Mercator 1/36° regional model w assim in 2014
• Analyses of sQG being developped (G. Lapeyre)
• Operational wave models – MARS3D via Previmer (F. Arduin)
1-13 AirSWOT January 2013
AirSWOT CFO-Sat
Ideally, could fly AirSWOT at same time as Airborne CFOSat over ocean surfaces for :
• ocean topography & slope/currents : AIrSWOT
• Surface rugosity / wind / wave conditions from CFO-Sat / SWIM
• Require 2 aircraft in co-ordinated flight financed by the CNES.
SWIM instrument onboard CFOSAT : Surface Waves Investigation & Monitoring Real aperture radar in Ku-band Will measure: • Directional wave spectrum in 70-500 m wavelength range • SWH and wind speed from nadir • σ0
1-14 AirSWOT January 2013
AirSWOT Bay of Biscay – 2016-2017
More extensive field campaign : - Strong tides and atmospheric forcing - Dynamics : coastal currents, river inputs, tidal mixing, Swoddies - In-situ monitoring : HF Radar, Argo, gliders, Ferrybox T-S, cruises - HR operational ocean models, w & w/o tides & assim (Mercator 1/36°), nested coastal and wave models
Modis ocean colour image
ERS1 SAR Image June 1992 100km x 100 km. (ESA)
1-15 AirSWOT January 2013
AirSWOT Planning
• Requests for coastal research ship time (Thethys) to be submitted en Feb 2013 for 2014
• SHOM (French Navy) is also interested in participating • Requests for loan of 2 gliders from INSU Instrument
Park, -> Possibility to mount a « light » in-situ array for CalVal of
AirSWOT in spring 2014, However … • Need more information from Project on AirSWOT error
budget and proposed SNR • Prefer that these French ocean measurements be made
AFTER preliminary analysis & feedback from US ocean campaigns …
1-16 AirSWOT January 2013
AirSWOT
Thank you
1-17
AirSWOT January, 2013
SWOT AirSWOT Basics
• Nominal 5 km swath • Range resolution: 75cm/1.9m • Azimuth resolution: <1m • Ka-band SAR interferometer/
altimeter measures water level elevation with a precision of ~3 cm over 50 m pixels (or, equivalently, 1.5 mm precision over 1 km pixels)
• Final accuracy depends on GPS, IMU, and calibration
• Incidence angles:0o-~25o • Additional measurements: Ka-
band radar cross section, radial surface water velocity, near IR imagery
• Check-out platform: King Air B200
1-18
AirSWOT January, 2013
SWOT Observation strategy overview of the intense air-sea fluxes, Spring 2013
Atmosphere • ATER-42 aircraft booked for a period of one month, and on alert for intense events.
=> Plane based at Montpellier
=> Measurements made of atmospheric boundary layer
• CNES Aeroclipper balloons (with observations of the atmospheric boundary layer and thermister strings in the upper ocean)
Ocean • Météo-France weather buoy : wind, waves, radiative fluxes, SST, SSS, with 20 ocean thermistors 0-250m. • 12 lagrangian SVP drifters (SST, SSS, SLP) • monthly glider observations from Marseilles to Meteo buoy to Banyuls & from Minorque – Marseille • 6 additional gliders during HyMEX-Mermex campaigns (including backscatter & biogeochemistry) • Hydrographic sampling : DoWex campaign • Argo floats with rapid sampling of surface mixed layer & biogeochemistry
Hydrology • In-situ soil moisture and river levels • HF river gauges on Gard, Ardeche, … • LIDAR aircraft observations over rivers
