The project aims at quantifying the effects of precipitation patterns changes on the rivers solid discharge characteristics and their impact on the coastal area. It focuses on the complex system formed by the Danube, its delta and the Black Sea adjacent coastal area.
The project has a multi-disciplinary character, proposing a novel, integrated approach to analyze the chain impact of precipitation patterns changes (within the climate change context) on the stability of fragile ecosystems, such as the coastal regions, due to modifications of river flow characteristics.
The specific objectives of the project are the following:
- To accurately map the distribution of SPM based on Earth Observation data over the main Danube branches and in front of the river’s mouths. It implies complex processing of satellite data, combination of multiple sources of imagery and in-situ data collection for refining the inversion algorithm used to translate the remote sensing reflectance (optical properties measured by the satellite) to SPM. Activities associated with this objective will be a continuation of previous studies undertaken by the project director and the mentor in the area of interest (Constantin et al., 2016, Cheval and Constantin, 2019). Processing schemes were already developed and a first set of in-situ SPM measurements are available (to be completed with data collected during future extreme events).
- To collect high quality in-situ measurements of SPM, POM and CDOM concentrations. Such datasets are not currently available (except SPM) for the region of interest, and they will be used to characterize in detail the Danube discharge, not only from quantitative point of view (SPM) but also qualitative (POM, CDOM).
- To quantify the decadal changes of precipitation patterns in the Danube catchment. Special attention will be given to basins downstream of major dams, such as Portile de Fier, since these ones (e.g. Siret, Ialomita) can have a greater influence on the final sector of the Danube. While there are several metrics used to describe precipitation, it is important to select the ones that can be used to quantify the intensity of special/extreme events (Pendergrass, 2018), with relevance for the SPM, POM and CDOM dynamics. To this regards, statistics related to short periods of time, such as total precipitated water in one day/hour and associated anomalies, will be empowered mostly within the project.
- To analyze the patterns of solid discharge output into the Black Sea in correlation with the precipitation patterns in the Danube’s hydrological basin. This will be performed both in terms of concentration and composition – total SPM and organic versus inorganic fractions. While SPM concentrations can be successfully retrieved based on satellite information, it is not the case of parameters referring to the mineral and organic composition, either suspended or dissolved, of the water. Indicators such as Particulate Organic Carbon/Matter (POC or POM) or Colored Dissolved Organic Matter (CDOM) require precise algorithms that need to be adapted to the region of interest (in our case – very complex, from optical point of view) (IOCCG, 2000; Stramski et al., 2008). A first step is to determine such indicators based on in-situ measurements and quantify the differences between normal discharge conditions and extreme events, activities which are foreseen within the proposed project.