M I P j l M H RiM.-I. Pujol, M.-H. Rio,

A Kerguelen regional Sea Level product C. Renaudie, Y. Faugère,A Kerguelen regional Sea Level product C e aud e, augè e,G Dibarbouree gue e eg o a Sea e e p oduct G. Dibarboure

CLS Toulouse Franceto support the KEOPS2 experiment CLS , Toulouse, Franceto support the KEOPS2 experimentF D’O idi

to support the KEOPS2 experimentF. D’Ovidio

LOCEAN - IPSL, Paris, France, ,

R MorrowR. MorrowJ Lambin E BronnerThe KEOPS2 campaign (PI: S Blain Observatoire Océanologique de Banyuls sur mer UPMC) took place during October J. Lambin, E. Bronner

CNES T l FThe KEOPS2 campaign (PI: S. Blain, Observatoire Océanologique de Banyuls sur mer, UPMC) took place during October-

CNES , Toulouse, FranceNovember 2011 around Kerguelen Islands. The aim is to elucidate the response of ecosystem functioning and of theNovember 2011 around Kerguelen Islands. The aim is to elucidate the response of ecosystem functioning and of thebiogeochemical cycles to natural iron fertilization a key factor controlling ecosystem dynamics (including CO2 export) in thebiogeochemical cycles to natural iron fertilization, a key factor controlling ecosystem dynamics (including CO2 export) in theSouthern ocean and other basins It is a multidisciplinary campaign heavily relying on high quality satellite dataSouthern ocean and other basins. It is a multidisciplinary campaign heavily relying on high quality satellite data.

A specific support from CNES enables KEOPS2 to benefit from such products both in real time and delayed time production CNES contributes via the.A specific support from CNES enables KEOPS2 to benefit from such products, both in real time and delayed time production. CNES contributes via the Ssalto/DUACS project and in collaboration with LEGOS/CTOH, to specifically process altimeter products and derivates for the Kerguelen area. The productsSsalto/DUACS project and in collaboration with LEGOS/CTOH, to specifically process altimeter products and derivates for the Kerguelen area. The products were validated in collaboration with LOCEANwere validated in collaboration with LOCEAN.

Altimeter data were specifically processed for the construction of KerguelenA regional Mean Dynamic Topography was specifically processed for the Altimeter data were specifically processed for the construction of Kerguelen i l d t I t i l i t i

g y p g p y p y pKerguelen area (Fig 1) It benefits from improved processing the latest geoid model regional products. Improvements mainly consist in :Kerguelen area (Fig 1). It benefits from improved processing, the latest geoid modeli l di GOCE d t d dditi l i it t ith i d iincluding GOCE data, and additional in situ measurements with improved processing.

Zonal correlation scales used for regional productiono Improved noise measurementg g

g po Improved noise measurement Global MDT (CNES-CLS09)The regional MDT allows a better restitution reduction on along-track data (filtering)Global MDT (CNES CLS09)The regional MDT allows a better restitution reduction on along track data (filtering)

Improved correlation scales to takeof the mean circulation in the area, with for o Improved correlation scales to take ,instance an improved reconstruction of the into account the geographical variabilityinstance, an improved reconstruction of theF T h C t d th D W t into account the geographical variability

f th i l (Fi 2)Fawn Trough Current, and the Deep Western

of the signal (Fig 2).g

Boundary Current loop signature observedo High resolution (14 km for along-track

Boundary Current loop signature, observedaround 80°E 55°S o High resolution (14 km for along track

d 1/8° f id )around 80°E,55°S.

and 1/8° for grids) kmRegional MDT (V2)In situ data from KEOPS2 g ( )In situ data from KEOPS2

Map of Sea Leval Anomalie and Absolutecampaign were later used to Map of Sea Leval Anomalie and Absolute D i T hi ll

campaign were later used toimprove the regional MDT Dynamic Topographie, as well as improve the regional MDT

geostrophic currents were delivredmain impact East of the geostrophic currents were delivred.pKerguelen IslandKerguelen Island.

Variance(along-track – mapsGl b l) – Variance(along-track – mapsR i l)Variance(along track mapsGlobal) Variance(along track mapsRegional)

Comparison between SLA maps and EnvisatComparison between SLA maps and Envisat l t k d t iti l th t thalong-track data : positive values mean that the Drifter velocities measured between

regional product better fit along-track signal.Drifter velocities measured between

15/10/2011 and 31/05/2012 regional product better fit along track signal. 183000 velocity measurements

R i l d t b tt l th l i l th thRegional products better resolve the mesoscale signals than the g p gexisting global productsexisting global products.

Drifter velocity (cm/s)e e oc y (c /s)

CTD profiles measured between 15/10/2011 pand 19/11/2011

Dynamic Heights 75 profilesDynamic Heights(cm) Anomaly relative ( ) y

to a climatology The regional products largely contribute to the KEOPS2gy The regional products largely contribute to the KEOPS2 Campaign :Campaign :•before and during the campaign:before and during the campaign:

h ti it i f f t t– have synoptic monitoring of surface state– help predict the drifter trajectories

Th t t l f t l d li d Th Ek t i dd d thelp predict the drifter trajectorieshelp choose the positions of in sit meas rementsThe total surface currents are also delivered. The Ekman component is added to – help choose the positions of in situ measurementsp

the absolute geostrophic currents (deduced from altimeter product) It is deduced from •After the campaign :the absolute geostrophic currents (deduced from altimeter product). It is deduced from After the campaign :Validate and interpret the measurements acquired during the campaignECMWF wind stress analysis applying a regional Ekman model, specifically adjusted to –Validate and interpret the measurements acquired during the campaign.y pp y g g , p y j

the Kerguelen area KEOPS2 Campaign contributes to improve the altimeter productsthe Kerguelen area. KEOPS2 Campaign contributes to improve the altimeter products– In situ measurementsIn situ measurements

V lid ti ith t l d t d di ti– Validation with external data and new diagnostics– User feedback on products qualityUser feedback on products quality

The improved precision of the regional altimeter products and p p g pMDT is confirmed by comparison with Chlorophyll concentration:MDT is confirmed by comparison with Chlorophyll concentration:

lti t i l d t d l t t daltimeter regional products reproduce mesoscales structures and g p pfilaments underlined by surface chlorophyll concentration They allows anfilaments underlined by surface chlorophyll concentration. They allows an

t d t ti f f t d fil t i L i l iaccurate detection of fronts and filaments via a Lagrangian analysis.

ADT (cm)ADT (cm)

Ob ti f thObservation of the bloom extensionThe regional product is clearly better in

All the products are available viabloom extensiong p y

predicting the southern flank of the bloomAll the products are available via ftp AVISO in the directory

predicting the southern flank of the bloomextension (Credits LOCEAN/ F d'Ovidio)ftp AVISO in the directory extension. (Credits LOCEAN/ F. d Ovidio)(M d t il i b )/donnees/ftpsedr/DUACS/experi (More details on www.aviso.oceanobs.com)p p

mental/regional-kerguelenmental/regional-kerguelen( t d* )(granted* access). Prediction of the(g )

*SubscribePrediction of thebloom extensionTh i l lti t d tAVISO bloom extension

i Gl b l (C)The regional altimeter products

using Global (C) org p

accuracy makes it possible toRegional (D)

accuracy makes it possible tot d i th k l f h i t lDon’t hesitate to use them and give your Regional (D)

altimeter productstudying the key role of horizontalDon t hesitate to use them and give your feedbacks to AVISO ! altimeter producttransport in structuring thefeedbacks to AVISO ! transport in structuring the

phytoplankton abundancephytoplankton abundance.