On Using Lagrangian Drift Simulations to Aid Interpretation of in situ Monitoring Data

Ulrich Callies,Markus Kreus,Yoana G Voynova,Wilhelm Petersen

doi:10.3389/fmars.2021.666653

Ulrich Callies, Markus Kreus + Show 2 more

Open Access

https://doi.org/10.3389/fmars.2021.666653

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Abstract

One key challenge of marine monitoring programs is to reasonably combine information from different in situ observations spread in space and time. In that context, we suggest the use of Lagrangian transport simulations extending both forward and backward in time to identify the movements of water bodies from the time they were observed to the time of their synopsis. We present examples of how synoptic maps of salinity generated by this method support the identification and tracing of river plumes in coastal regions. We also demonstrate how we can use synoptic maps to delineate different water masses in coastal margins. These examples involve quasi-continuous observations of salinity taken along ferry routes. A third application is the synchronization of measurements between fixed stations and nearby moving platforms. Both observational platforms often see the same water body, but at different times. We demonstrate how the measurements from a fixed platform can be synchronized to measurements from a moving platform by taking into account simulation-based time shifts.

Highlights

In situ observations from FerryBoxes installed on ships of opportunity provide measurements for a large number of different parameters with high temporal resolution
We address a couple of examples that refer to FerryBox observations in the southern North Sea (Petersen, 2014)
The third example refers to a comparison of the same FerryBox data with salinity measurements from the CEFAS Gabbard Buoy, a fixed station adjacent to the ferry route

Summary

Introduction

In situ observations from FerryBoxes installed on ships of opportunity provide measurements for a large number of different parameters with high temporal resolution. We address a couple of examples that refer to FerryBox observations in the southern North Sea (Petersen, 2014). Localized in situ observations are, only limited snapshots of an ongoing evolution of water masses, ranging from the large-scale ocean circulation on the order of years (Sheehan et al, 2017) to the smaller meso- and submeso-scale structures (Oka et al, 2014; Schubert et al, 2019). Proper interpretation of oceanographic measurements often requires knowledge about the origin and history of the regional water masses. This would be analyzed within a Lagrangian framework. We demonstrate the usefulness of such an approach with three examples

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