DrakkarJanuary 2007

NEMO and Ocean Reanalysis

• Ocean Model Strategy in UK now focussed on NEMO (MetO+Hadley, ECMWF, Reading, NOC, POL, UEA)

• Rapid Climate change project– Greg Smith– Ben McDonald (PhD) (Historical

and Rapid array focus)– NOC collaboration: Brian King

(ARGO focus)

• Ocean Reanalysis at 1 and ¼– Special project time at ECMWF– Can also run on Reading Cluster

(57/64 processors for ¼ )– Developing e-Science access to

POL+BAS clusters (400+ proc)

NEMO ¼ output from compute cluster

DrakkarJanuary 2007

Developing NERC Grid

DrakkarJanuary 2007

Biogeochemical modelling

• Collaboration with UEA, NOC and Met Office

• 2 or (1 future) global NEMO with biogeochemistry– Carbon cycle modelling– NPZD v. PFT modelling

Planktom5 has 3 PFTs +Bacteria+Nutrients = 29 prognostic variables

– Currently NEMOv1 (moving v2)• Implement physical data

assimilation to:– Correct physical model biases– Explain inter-annual variability in

bio-carbon measurements eg. AMT

– Semi-prognostic v. Full Assim. => Greg

Mixed Phytoplankton Chlorophyll (mol/l)

DrakkarJanuary 2007

Arctic Ocean modelling for IPY (future)

• Greg already involved in EU Damocles IPY project (1 year)• UK IPY project ASBO (Arctic Shelf and Basinwide Oceanography)

– Collaboration with UCL (PI Seymour Laxon), NOC (Sheldon Bacon) and Met Office

– Should start spring 2007. New Post Doc needed !!!!!!!!!!!!!!!!!!• ASBO will extend assimilation methods for Arctic seas

– Assimilate hydrography data from IPY Arctic cruises, especially Canadian CAME Circum Shelf-break cruise

– Extend Gregs work to include Altimeter assimilation (using ERS, ENVISAT and preparing for Cryosat 2 data) using Laxons work on sea ice drafts from altimetry

– Aimed at Arctic shelf Arctic basin N Atlantic freshwater budget – Expect to use 1 and ¼ NEMO models– Possibly using CICE going into NEMO (UCL)– Compare with Inverse models (NOC Navaro Gab…)

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Click to Apply

DrakkarJanuary 2007

Relevant questions:

• Can we recover water mass variability and THC changes using data assimilation?

• How can we best use the available observations?

• What does the data assimilation tell us about model errors?

Main aim: Produce high-resolution multi-decadal global ocean

reanalysis using physically-based assimilation techniques.

Use this reanalysis to study water mass variability and the effect on ocean climate signals.

DrakkarJanuary 2007

How can we best make use of the available observations?

Two types of variability: dynamic and that due to water mass changes

Dynamic: high frequency short correlation scales

Watermass: low frequency long correlation scales

DrakkarJanuary 2007

 

One point correlation maps from HadCEM

S(z) S(T)

DrakkarJanuary 2007

NEMO: Plans and progress...

• Strategy: – Use 1o model for testing the assimilation scheme and to perform multiple

sensitivity studies. – Then transfer assimilation scheme to 1/4o global model to produce high-

resolution reanalysis.• Current Status:

– 2°, 1 ° and 1/4 ° resolution global NEMO ice-ocean models set-up and running, both at ECMWF and ESSC cluster.

– Several 45 year hindcasts of 1° NEMO complete.– Generalized observation operator has been implemented in NEMO– Can now begin implementing assimilation system

DrakkarJanuary 2007

NEMO in Google Maps/Earth

• It works!! • But still needs some adjustments• Click below (best with Firefox)

http:/lovejoy.nerc-essc.ac.uk:8080/ncWMS/godiva2.html

• Please note: NEMO output should be made CF1.0 compliant NetCDF !

DrakkarJanuary 2007

NEMO in GoogleEarth

http://lovejoy.nerc-essc.ac.uk:8080/ncWMS/godiva2.html