Modeling and Multi-Temporal Characterization of Total Suspended Matter by the Combined Use of Sentinel 2-MSI and Landsat 8-OLI Data: The Pertusillo Lake Case Study (Italy)

Emanuele Ciancia,Nicola Pergola,Angelo Palombo,Teodosio Lacava,Valeria Satriano,Valerio Tramutoli,Simone Pascucci,Stefano Pignatti,Alessandra Campanelli

doi:10.3390/rs12132147

Abstract

The total suspended matter (TSM) variability plays a crucial role in a lake’s ecological functioning and its biogeochemical cycle. Sentinel-2A MultiSpectral Instrument (MSI) and Landsat 8 Operational Land Instrument (OLI) data offer unique opportunities for investigating certain in-water constituents (e.g., TSM and chlorophyll-a) owing to their spatial resolution (10–60 m). In this framework, we assessed the potential of MSI–OLI combined data in characterizing the multi-temporal (2014–2018) TSM variability in Pertusillo Lake (Basilicata region, Southern Italy). We developed and validated a customized MSI-based TSM model (R2 = 0.81) by exploiting ground measurements acquired during specific measurement campaigns. The model was then exported as OLI data through an intercalibration procedure (R2 = 0.87), allowing for the generation of a TSM multi-temporal MSI–OLI merged dataset. The analysis of the derived multi-year TSM monthly maps showed the influence of hydrological factors on the TSM seasonal dynamics over two sub-regions of the lake, the west and east areas. The western side is more influenced by inflowing rivers and water level fluctuations, the effects of which tend to longitudinally decrease, leading to less sediment within the eastern sub-area. The achieved results can be exploited by regional authorities for better management of inland water quality and monitoring systems.

Highlights

Inland freshwater bodies are key providers of services to local communities, being crucial sources of drinking water and major hubs for recreational activities [1]
The accuracy of the dark spectrum fitting” technique (DSF) atmospheric correction was assessed through the comparison between the MultiSpectral Instrument (MSI)-Rrs(λ) and the corresponding in situ measurements, considering that no Operational Land Instrument (OLI) overpasses were concurrent with the in situ sampling dates
We evaluated the capability of MSI–OLI combined data in characterizing the total suspended matter (TSM) multi-year variability in PL

Summary

Introduction

Inland freshwater bodies are key providers of services to local communities, being crucial sources of drinking water and major hubs for recreational activities [1]. Like many other ecosystems, lakes are affected by increasing environmental pressures due to co-occurring stressors such as climate change, contamination of organic and inorganic substances, and anthropogenic influences, which threaten their ecological functions [2,3] For this reason, European legislation such as the Marine Strategy Framework Directive (MSFD, 2008/56/EC) and Water Framework Directive (WFD, 2000/60/EC and amendments) requires member states to assess the ecological status of water bodies based on different quality indicators, such as water transparency [4]. The new generation of sensors such as the MultiSpectral Instrument (MSI) on Sentinel-2A/B(S2A/B) and the Operational Land Imager (OLI) on Landsat 8 (L8) allow these limitations to be overcome, offering unprecedented opportunities for lake remote sensing, they are designed mostly for land applications [21]

Results

Discussion

Conclusion