Use of earth observation data and numerical modeling in the development of marine downstream services in Estonia

Abstract

The objective of the Global Monitoring for Environment and Security (GMES) is to provide, on a sustained basis, reliable and timely services related to environmental and security issues in support of public policy makers' needs. MyOcean is the implementation project of the GMES Marine Core Service (MCS), aiming at deploying the first concerted and integrated pan-European capacity for Ocean Monitoring and Forecasting (www.myocean.eu.org). MyOcean develops upgraded European capabilities for reference marine information and provides a wide range of key ocean indicators. The MCS provides information to intermediate users who combine it with other forms of information and data to provide customized downstream services for end users. The end users range from wide public to special target groups. Downstream marine services in Estonia are built on in-situ real time and near real time measurements, satellite remote sensing imagery and numerical modeling. Two-day marine forecasts for the North-Eastern Baltic Sea are produced by 3D circulation model HIROMB-EST. The downstream service portfolio consists of following items. Real time sea level observations including history and two-day forecasts on 12 locations around the Estonian coast are available in the Internet. Sea surface temperature (SST) and salinity are complimented with near real time ferry-box observations on the cross-section between Tallinn and Helsinki. During cloud free sky SST charts are produced using MODIS (Moderate Resolution Imaging Spectroradiometer) imagery for the Gulf of Finland and Gulf of Riga. Illegal oil spills are detected from SAR imagery. The drift of the slick is simulated by Seatrack-Web and potential polluters are identified combining Seatrack Web and the Automatic Identification System (AIS). The monitoring of suspended particulate matter during harbor dredging is based on MODIS and MERIS (MEdium Resolution Imaging Spectrometer) data. The laboratory analyses of water samples are used for the calibration and validation of satellite products. The in situ measurements of vertical profiles of absorption and attenuation coefficients are used to determine the profiles of particle origin, concentration and size distribution. Operational ice extent monitoring using SAR data is rather widespread. Optical remote sensing imagery from MODIS and MERIS sensors complement SAR imagery. Ice concentration maps are produced using the histogram analysis of MODIS 250 m reflectance data. This data is used for model evaluation with the purpose to get reliable ice forecast from the HIROMMB-EST model. Spectral optical remote sensing data from MERIS helps to identify different ice types. The determination of high spatial resolution marine and coastal wind from the Advanced Synthetic Aperture Radar (ASAR) is quite a novel application in the Estonian waters. Wind field data can be retrieved from ASAR C-band data and model results using CMOD algorithm.