Using MERIS data to assess the spatial and temporal variability of phytoplankton in coastal areas
(English)Manuscript (preprint) (Other (popular science, discussion, etc.))
This study evaluates the use of MERIS data (2003-2011) in coastal zone monitoring using Himmerfjärden bay as an example. The bay is one of the most frequently monitored coastal areas in the world, allowing for a rigorous comparison between satellites and ship-based monitoring data. The validity of the processors used in the study have been previously assessed and include correction for adjacency effects from land. Furthermore, a new set of rigorous coastal flags developed by the ESA CoastColour project was applied to assure good data quality in the coastal zone.
MERIS data was used for the integration of chlorophyll a over each water body in the Himmerfjärden area, following the national water body classification by the Swedish Meteorological and Hydrological Institute (SMHI). Hovmöller diagrams were derived for different water bodies along a coastal gradient in order to display the phenology of phytoplankton in each water body. The Hovmöller diagrams were directly compared to the phenology graphs derived from ship-based in situ sampling. While increasing both the temporal and spatial resolution of chlorophyll data, MERIS satellite data can also be used to evaluate how representative in situ monitoring stations are for a given water body.
Chlorophyll a anomaly maps were produced for the bay and its adjacent areas for the years 2006, 2008 and 2010. The maps could be used to show events with high chlorophyll, both with natural causes (e.g. a Prymnesium polylepis bloom observed in summer 2008) and of anthropogenic causes (e.g. failure in the local sewage treatment plant resulting in a strong spring bloom in 2006). Anomaly maps thereby allow to scan larger coastal stretches to discriminate areas that may require additional sampling by ship, or to identify areas that do not differ much from the median value of the MERIS time series.
MERIS, Himmerfjärden, Water quality, Time Series, Chlorophyll, Baltic Sea
Oceanography, Hydrology, Water Resources
Research subject Marine Ecology
IdentifiersURN: urn:nbn:se:su:diva-123721OAI: oai:DiVA.org:su-123721DiVA: diva2:877464
ProjectsEUFP7 Strategic partnership for improved basin-scale water quality parameter retrieval from optical signatures (WaterS) Ref.: 251527FP7 EuRuCAS (project no. 295068); mobility exchange with NIERSCESA/ESRIN contract 21524
FunderSwedish National Space Board, 165/11Swedish National Space Board, 147/12Ecosystem dynamics in the Baltic Sea in a changing climate perspective - ECOCHANGE, 4315403EU, FP7, Seventh Framework Programme, 251527EU, FP7, Seventh Framework Programme, 295068