University of Tasmania

File(s) under permanent embargo

Demonstrating the complementarity of observations in an operational ocean forecasting system

journal contribution
posted on 2023-05-19, 08:53 authored by Lea, DJ, Martin, MJ, Oke, PR
We have performed a series of near-real-time observing system experiments with FOAM, the Met Office operational ocean forecasting system. These were conducted in parallel to the operational suite and identical to it except that certain observation types were excluded. At the start of each month the parallel system was reset to the operational restart and a run started with a different observation type excluded: in February -XBT; March -TAO/TRITON; April -Jason-2 altimeter; May -all altimeter; June -AVHRR sea-surface temperature (SST) data; and July -Argo data. We show that the existing ocean observing systems offer a good deal of complementary information. All components of the observing system offer unique, independent information that help initialise, and improve, operational ocean forecasts. Withholding XBTs causes little impact on globally averaged metrics, for example RMS innovations. However, locally we see long-lasting temperature impacts (∼1 °C) near XBT transects. Withholding TAO/TRITON data has a regional impact increasing the tropical Pacific RMS temperature and salinity innovations by 39 and 60%, respectively. Withholding Jason-2 data results in a global 4% increase in the RMS sea-surface height (SSH) innovations, and small-scale changes in temperature and salinity of about 2 °C at 100 m depth, and ∼0.2 psu near the surface. Withholding all altimeter data leads to a 16% increase of the RMS SSH innovations. We also see changes in other model variables similar in magnitude to those from withholding Jason-2, but more widespread. Withholding AVHRR SST data produces significant changes around 1 °C in model temperature at the surface and within the surface mixed layer, but there is little or no effect below this. Withholding Argo data for 1 month leads to a 5% increase in the temperature and salinity innovations, and changes in SSH of up to 5 cm.


Publication title

Quarterly Journal of the Royal Meteorological Society










Institute for Marine and Antarctic Studies


Royal Meteorological Soc

Place of publication

104 Oxford Road, Reading, England, Berks, Rg1 7Lj

Rights statement

Copyright 2013 Royal Meteorological Society and Crown Copyright, Met Office

Repository Status

  • Restricted

Socio-economic Objectives

Oceanic processes (excl. in the Antarctic and Southern Ocean)

Usage metrics

    University Of Tasmania


    Ref. manager