Drakkar January 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

Drakkar January 2007 Developing NERC Grid

Drakkar January 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)

Drakkar January 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 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…) Click to Apply

Drakkar January 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.

Drakkar January 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

Drakkar January 2007 One point correlation maps from HadCEM S(z)S(T)

Drakkar January 2007 NEMO: Plans and progress... Strategy: –Use 1 o model for testing the assimilation scheme and to perform multiple sensitivity studies. –Then transfer assimilation scheme to 1/4 o 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

Drakkar January 2007 NEMO in Google Maps/Earth It works!! But still needs some adjustments Click below (best with Firefox) Please note: NEMO output should be made CF1.0 compliant NetCDF !

Drakkar January 2007 NEMO in GoogleEarth