EQUIPEX NAOS WP5 : Deep oxygen floats in the North- Atlantic

Transcription

1 EQUIPEX NAOS WP5 : Deep oxyge floats i the North- Atlatic Virgiie Thierry Guillaume Maze, Herlé Mercier, Cécile Cabaes, Virgiie Racapé Laboratoire d Océaographie Physique et Spatiale UMR 6523 CNRS / IFREMER / IRD / UBO IUEM

2 WP5: Scietific ad techological objectives Deploymet of 23 Deep-Arvor floats with oxyge Marie Core Service sesor i the North-Atlatic Ocea Implemet a pilot experimet for O2 ad deep data Deploy Argo-O2 floats ad Deep-Arvor floats i the North-Atlatic Ocea Implemet the correspodig data stream at iteratioal level Prepare the future iteratioal Deep-Argo ad Argo-O2 array Techological objective: Demostrate the capacity of the Deep-Arvor float at acquirig deep (below 2000m depth) ad oxyge data of high-quality Scietific objective : Ivestigate deep covectio ad water mass vetilatio i order to ivestigate the iput ad propagatio of climatic aomalies withi the ocea iterior

3 Pilot experimet for O2 ad Deep-Argo data Marie Core Service Float deploymet 10 Deep-Arvor floats with O2 sesor deployed i the North-Atlatic Ocea More floats will be deployed i the comig years (remaiig NAOS floats ad floats fuded by CPER Euro-Argo over ) Those data complemet Argo-O2 floats deployed i the North-Atlatic sice 2010

4 Pilot experimet for O2 ad Deep-Argo data Data stream ad deploymet strategy Marie Core Service We established the the data maagemet procedure for O2 data from decodig to qualificatio We cotribute to establish the Europea strategy regardig the Deep-Argo ad Argo-O2 arrays i agreemet with Europea parters ad the iteratioal Argo program

5 Demostrate the capacity of the Deep-Arvor float at acquirig deep (below 2000m depth) ad Marie Core Service oxyge data of high-quality The Deep-Arvor float is able to achieve more tha 140 cycles Owig to the measuremets below 2000m, the Deep-Arvor floats revealed that a fresh bias was preset i the classical Argo floats. Such bias is easily correctable ad has bee resolved by ehaced quality checks before deploymet ad a modificatio of the storage procedure

6 Demostrate the capacity of the Deep-Arvor float at acquirig deep (below 2000m depth) ad Marie Core Service oxyge data of high-quality The Deep-Arvor float is able to achieve more tha 140 cycles Owig to the measuremets below 2000m, the Deep-Arvor floats revealed that a fresh bias was preset i the classical Argo floats. Such bias is easily correctable ad has bee resolved by ehaced quality checks before deploymet ad a modificatio of the storage procedure

7 Demostrate the capacity of the Deep-Arvor float at acquirig deep (below 2000m depth) ad Marie Core Service oxyge data of high-quality We developed the LOCODOX tool to correct oxyge sesor bias ad drift ad to geerate DM files i the Argo format (subcotractig with Altra) Correctio based o WOA or o a referece profile Adjusted data from 32 floats were submitted to Coriolis ad are ow available to the scietific commuity The tool is still uder developmet (2,5 moths /year) : implemetatio of the correctio based o i air measuremets

8 Scietific aalyses Ivestigate deep covectio i the Irmiger Sea ad documet a exceptioal Marie Core Service deep covectio evet that occured at basi scale durig witer : PhD thesis A. Piro (Piro et al, 2016, 2017) Potetial Desity (σ θ, kg.m -3 ) LAB box IRM box NAC Depth (m) σ θ O 2 SPMW σ θ O (a) Oxyge Saturatio (O 2, %) (c) Potetial Desity (σ θ, kg.m -3 ) Saliity Due to exceptioal witer heat loss, the mixed layer observed i March i the Imriger Sea are the deepest mixed layer ever observed i this basi. epth (m) σ θ SCF box

9 Scietific aalyses Marie Core Service Ivestigate ew pathways for the deep water masses as revealed by Deep-Arvor float trajectory ad their coectio with the surface circulatio; post-doc V. Racapé Surface geostrophic velocity (m/s) (AVISO+, resolutio averaged o oe Deep-Argo cycle) Deep-Argo floats 3 deep-argo floats deployed i Jully 2015 (RREX cruise) 1 cycle = 10 days Parkig depth = 2750 dbar durig 9 days (to sample ISOW) T, S, O2, GPS positio (Iridium)

10 Scietific aalyses Marie Core Service Dyamical cotext Large scale circulatio scheme i the North Atlatic subpolar gyre Deep circulatio σ 0 > 27.8 DWBC CGF Z QUESTIONS? [Daiault et al., 2016] Why did oe of the floats reach the Irmiger basi? Why did they move apart at 37 W? Did the red float sample the DWBC?

11 West East Scietific aalyses Marie Core Service Dyamical coditios durig float deploymet Theta saliity O 2 diagram for RREX statios 114 to 131 Absolute geostrophic velocity refereced to s-adcp data (m/s) (com. pers. T. Petit) SPMW St 120 Float deploymet July 3th, 2015 St 120 Eastward Barocliic structure from surface to depth

12 Saliity ad Oxyge cocetratio sampled by the 3 floats Scietific aalyses Marie Core Service ~37 W SPMW ISOW Westward circulatio costraited by SPMW Westward dilutio of the ISOW core

13 Scietific aalyses Marie Core Service Optimum Multiparameter aalysis to determie mixig coeficiets for the deep layers (27.8 < σ 0 < 27.88) Ɵ-S-O 2 diagram for cy. 1 to 21 of red float WORK IN PROGRESS Methodology LSW SPMW ISOW NEADW Defie the source water types (SWT) Defie the weigth (W) of each parameters (j = Ɵ,S,O 2 + mass coservatio) Defie mixig figures (o more tha 3 SWTs for our case) Vertical limit (27.8 < σ 0 < 27.88) Various cofiguratios; for example (1) SWT1 2 ad 3; (2) = SWT1 2 4 Idetify the best cofiguratio Fial residual = sqrt[σ(res j ² / W j ²)] DSOW

14 Water masses cotributio betwee σ ad OMP results SPMW LSW Marie Core Service NAC LSW ISOW DWBC ISOW SPMW Mai water mass progressively dilluted with NEADW DSOW NEADW DWBC characterisc

15 Summary ad Future work Marie Core Service Surface geostrophic velocity (m/s) (AVISO+, resolutio averaged o oe Deep-Argo cycle) Deep circulatio : Direct trajectory from CGFZ to the DWBC (suggested by McCartey (1992) Why is it ot here? Is it permaet? What is the role of SPMW? Is it a respose to the chage i atmospheric forcig (NAOeutre >> NAO+)? Westward erosio of ISOW core evaluatio of the mixig coefficiet (work i progress) Ifluece of the NAC o the Deep circulatio. How? What are the cosequeces o the propagatio of climatic aomalies

16 Perspectives Cotiue Marie Core deploymet Service of Deep-Arvor data i the North-Atlatic ocea 11 remaiig NAOS floats CPER Euro-Argo floats (15 floats/year available, some via the GMMC) Scietific objective: Formatio, pathways ad mixig of deep water masses?

17 Perspectives Maitai Marie Core the Service North-Atlatic Argo-Deep pilot array Techological issue: Float ad sesor evaluatios Strategy assessmet : desity, parkig depth, cyclig period, cost Demostratio of data value o a short term Iitiate Deep-Argo time series to address the Deep-Argo objectives i 10 or 20 years from ow.

18 North-Atlatic Deep pilot array Program Marie Core Service Fudig Scietific project Float type ad umbers Deploymet Regio Argo-Frace NAOS V. Thierry OVIDE, RREX, OSNAP 16 Deep- Arvor 2017 ad 2018 Subpolar gyre (3 i Souther Ocea) Euro-Argo AtlatOS OVIDE, RREX, OSNAP, others 7 Deep-Arvor 2017 ad 2018 North-Atlatic Argo-Frace CPER Euro- Argo (Brittay) OVIDE, RREX, OSNAP 15 Deep- Arvor/year (5 years) North-Atlatic Argo-UK OSNAP, RAPID,? 8 Deep-APEX O2 2017? Argo-US Deep-Argo SIO 6 Deep-SOLOS 2017 Rapid Lie at 26 N 18