Assessing the impact of observations on ocean forecasts and reanalyses: Part 1, Global studies

P.R Oke,G Larnicol,Y Fujii,G.C Smith,D.J Lea,S Guinehut,E Remy,M Alonso Balmaseda,T Rykova,D Surcel-Colan,M.J Martin,A.A Sellar,S Mulet,V Turpin

doi:10.1080/1755876x.2015.1022067

Abstract

Under GODAE OceanView the operational ocean modelling community has developed a suite of global ocean forecast, reanalysis and analysis systems. Each system has a critical dependence on ocean observations – routinely assimilating observations of in-situ temperature and salinity, and satellite sea-level anomaly and sea surface temperature. This paper demonstrates the value and impact of ocean observations to three global eddy-permitting forecast systems, one global eddy-permitting model-independent analysis system, one eddy-resolving reanalysis system, and two seasonal prediction systems. All systems have been used to assess the impact of Argo profiles, including scenarios with no Argo data, and a degraded Argo array – unanimously concluding that Argo is a critical data set – the most critical for seasonal prediction, and as critical as satellite altimetry for eddy-permitting applications. Most systems show that TAO data are as important as Argo in the tropical Pacific, and that XBT data have an impact that is comparable to other data types in the vicinity of XBT transects. It is clear that no currently available data type is redundant. On the contrary, the components of the global ocean observing system complement each other remarkably well, providing sufficient information to monitor and forecast the global ocean.

Highlights

Global ocean forecasting is important for a range of publicgood and commercial applications (Davidson et al 2009)
Results are presented from a series of Observing System Experiments (OSEs) using eddy-permitting global ocean forecast and analysis systems, and seasonal prediction systems
Each study takes a different approach to quantifying the impact of observations on each forecast/analysis system

Summary

Introduction

Global ocean forecasting is important for a range of publicgood and commercial applications (Davidson et al 2009). It includes results from Observing System Experiments (OSEs), where different components of the GOOS (e.g. satellite altimetry, Argo profiles) are systematically withheld from an assimilating system.

Results

Conclusion