NIERSC

DETERMINATION OF WATER QUALITY PARAMETERS FROM SATELLITE DATA ON INLAND AND MARINE COASTAL WATERS

Standard algorithms for determination of water quality parameters from spaceborne dataare developed for open oceans as optically most simple waters and provided byNASA and ESA. However, they are untenable for inland waters as well as coastalmarine waters because of their optical complexity. We developed at the NansenCenter (NIERSC) new sophisticated algorithms allowing to solve this problem. Ouralgorithms employ such advanced techniques as multivariate optimization andartificial neural networks.

The applicationof such algorithms provide information about spatial and temporal variations ofabundance of phytoplankton - microscopic algae in natural waters as well assuspended mineral and dissolved organic matter, i.e. the components thatlargely determine the productivity and ecology of lakes and marine watersrelatively close to the shoreline.

As an example,below given is the field of phytoplankton in the White Sea obtained from spacefor the first time (left panel below). This pioneering work yielded sequencesof spatial distributions of the above parameters at unprecedentedly hightemporal resolution (5 days) throughout the ice-free period. Such distributionswere complemented with water surface temperature fields (right panel).Together, this synergistic data allows a more deep insight into the sea’shydrobiology, hydrodynamics and ecology.

The developed tools provide the possibility of studying over severalyears the trends in the dynamics of water quality parameters. This isexemplified below for the White Sea for the time period 1998-2004.It turned outthat general warming of weather conditions (and hence in the area of the WhiteSea) over the above period resulted in the increase of suspended minerals anddissolved organics but in a decrease of phytoplankton (shown in %% on the panelbelow).

It isattributed to worsening of the light regime in the sea’s bays (waters becamemore turbid) that leads to subdued photosynthesis, and alterations of food-webinteractions due to a decreased visibility in the water column.The above achievementswere part of a comprehensive investigation of the White Sea conducted by alarge team of Russian and foreign scientists.

Theresults of these studies were summarized in a monograph (see below). Themonograph describes not only the past and present status of the sea, but alsoconsiders some scenarios of its variations due to possible climate changes aswell as socio-economic changes. Such predictions are yielded due to a combinedapproach encompassing numerical modeling of hydrodynamic, hydrobiogeochemicaland as well as socio-economic processes.

For more information contact Dr. Dmitry Pozdnyakov:
Dmitry.Pozdnyakov@niersc.spb.ru

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