Understanding temporal dynamics of meteo-marine parameters at the Ċirkewwa Marine Park

Abstract

This study investigates the temporal variability of key meteo-marine parameters within the Ċirkewwa Marine Park (ĊMP), Malta, through the integration of in-situ observations and modelled datasets. This site was selected due to its ecological significance and exposure to dynamic coastal processes, providing an appropriate setting to assess atmosphere-ocean interactions. Particular emphasis is placed on subsurface sea temperature variability and the extent to which model outputs accurately represent observed conditions. A multi-method approach was employed, involving the deployment of temperature loggers at depths of 5 m, 10 m, 15 m, and 20 m to collect high-resolution hourly measurements. Following the loss of the 5 m logger, analyses were based on observations from the remaining depths. These measurements were complemented by meteorological parameters, including air temperature, wind speed, and direction, alongside model outputs from the Copernicus Marine Environment Monitoring Service (CMEMS). The combined datasets were analysed to evaluate temporal trends, vertical stratification, and the influence of atmospheric forcing on water column dynamics. Results demonstrate clear seasonal variability, with temperatures increasing from early summer to a peak in September, followed by a gradual decline into autumn. A persistent vertical gradient was observed, indicative of stratified conditions, although episodic wind events exceeding 5 m/s promoted short-term mixing and partial disruption of the thermocline. While modelled and observed datasets showed general agreement in near-surface trends, discrepancies became increasingly pronounced with depth, with CMEMS consistently underestimating deeper temperatures. This highlights limitations in the capacity of models to resolve fine-scale coastal processes and vertical structure. However, the study is constrained by its relatively short temporal coverage and limited spatial resolution, which restrict the generalisability of the findings. Despite these limitations, it provides a valuable high-resolution baseline for the ĊMP and underscores the importance of sustained, multi-depth monitoring and rigorous model validation to enhance understanding of coastal dynamics and inform effective marine management strategies.