1 Introduction

The Earth's oceans are a dynamic and complex system that plays a vital role in our planet's climate and ecosystem. The behavior of oceanic currents, in particular, is a fundamental component of this intricate system, influencing everything from weather patterns to marine life distribution. In an era where climate change and environmental sustainability are at the forefront of global concerns, accurate knowledge of oceanic currents is of paramount importance.

As researchers, oceanographers, and environmental scientists strive to enhance our comprehension of oceanic currents, a critical aspect emerges - the assessment of the accuracy and reliability of the data and models used to represent these currents. This assessment is crucial not only for advancing our scientific understanding but also for providing valuable information to policymakers, industries, and society at large.

This document serves as a comprehensive guide to the metrics employed for the assessment of oceanic current product performance. It addresses the need for users to gain a better understanding of the uncertainty and physical content of each product, providing a robust framework for evaluating the quality and reliability of oceanic current data.

The standard validation techniques using in-situ data are detailed in Section 2. An effective resolution computation is proposed (Section 3) which can help understand the spatial distribution of the energy content of the currents products at different spatial scales. The documents describes metrics for assessing the accuracy of current direction across oceanic fronts and the detection of eddy positions using Sea Surface Temperature (SST) data (Section 4). Metrics to specifically characterize the dynamics at stake in the currents products are then provided (Section 5) which can reveal the complexity of regional ocean dynamics and their interplay with oceanic currents. Finally, this document proposes Lagrangian diagnostics (Section 6) providing insights into particle trajectories and the chaotic nature of oceanic flow.

This comprehensive guide aims to empower scientists, researchers, and data users with the knowledge and tools needed to assess and enhance the accuracy and reliability of oceanic currents products. By better understanding the metrics used for evaluation, we can advance our knowledge of oceanic currents and contribute to informed decisions regarding the world ocean circulation.