This chapter reviews the role of ocean-atmosphere interactions over the Atlantic sector in NAO variability. The emphasis is on physical mechanisms, which are illustrated in simple models and analysed in observations and numerical models. Some directions of research are proposed to better assess the relevance of Atlantic air-sea interactions to observed and simulated NAO variability.

Contents

1. Introduction

2. The climate noise paradigm

3. The North Atlantic Ocean as a heat reservoir
3.1 The reduced thermal damping argument
3.2 Mechanisms of SST feedback in midlatitudes
3.3 Mechanisms of SST feedback in the tropics
3.4 SST impact on NAO in observations 3.5 Summary

4. The North Atlantic Ocean as a heat carrier
4.2 NAO / ocean circulation interactions on basin scale
4.3 Summary

5. Assessing the relevance of coupled processes to NAO variability