A5002484189- Marine and coastal ecosystems
- Water Quality Monitoring and Analysis
- Water Quality Monitoring Technologies
- Atmospheric and Environmental Gas Dynamics
- Remote Sensing in Agriculture
- Water Quality and Pollution Assessment
- Air Quality Monitoring and Forecasting
- Marine Biology and Ecology Research
- Atmospheric Ozone and Climate
- Water Quality and Resources Studies
- Oceanographic and Atmospheric Processes
- Calibration and Measurement Techniques
- Inertial Sensor and Navigation
- Marine and coastal plant biology
- Coral and Marine Ecosystems Studies
- Remote Sensing and Land Use
- Engineering Applied Research
- Environmental Changes in China
- Arctic and Antarctic ice dynamics
- GNSS positioning and interference
- Coastal and Marine Dynamics
- Microbial Community Ecology and Physiology
- Meteorological Phenomena and Simulations
- Remote Sensing and LiDAR Applications
- Marine and fisheries research
University of Tartu
2018-2025
Tartu Observatory
2012-2023
Institute of the Estonian Language
2023
Marine Institute
2023
Atmospheric correction over inland and coastal waters is one of the major remaining challenges in aquatic remote sensing, often hindering quantitative retrieval biogeochemical variables analysis their spatial temporal variability within environments. The Correction Intercomparison Exercise (ACIX-Aqua), a joint NASA – ESA activity, was initiated to enable thorough evaluation eight state-of-the-art atmospheric (AC) processors available for Landsat-8 Sentinel-2 data processing. Over 1000...
Abstract The development of algorithms for remote sensing water quality (RSWQ) requires a large amount in situ data to account the bio-geo-optical diversity inland and coastal waters. GLObal Reflectance community dataset Imaging optical Aquatic environments (GLORIA) includes 7,572 curated hyperspectral reflectance measurements at 1 nm intervals within 350 900 wavelength range. In addition, least one co-located measurement chlorophyll , total suspended solids, absorption by dissolved...
Many lakes in boreal and arctic regions have high concentrations of CDOM (coloured dissolved organic matter). Remote sensing such is complicated due to very low water leaving signals. There are extreme (black) where the reflectance values negligible almost entire visible part spectrum (400–700 nm) absorption by CDOM. In these lakes, only water-leaving signal detectable remote sensors occurs as two peaks—near 710 nm 810 nm. The first peak has been widely used eutrophic waters for more than...
Optical close-range instruments can be applied to derive water quality parameters for monitoring purposes and validation of optical satellite data. In situ radiometers are often difficult deploy, especially from a small boat or remote location. The insight spectrometer (WISP-3) is new hand-held radiometer quality, which automatically performs measurements with three (L sky , L u E d ) does not need connected cables electrical power during measurements. instrument described its performance...
Remote sensing studies published up to now show that the performance of empirical (band-ratio type) algorithms in different parts Baltic Sea is highly variable. Best performing are regions Sea. Moreover, there indication have be seasonal as optical properties phytoplankton assemblages dominating spring and summer different. We modelled 15,600 reflectance spectra using HydroLight radiative transfer model test 58 previously algorithms. 7200 were specific inherent (SIOPs) open 8400 with SIOPs...
A field intercomparison was conducted at the Acqua Alta Oceanographic Tower (AAOT) in northern Adriatic Sea, from 9 to 19 July 2018 assess differences accuracy of in- and above-water radiometer measurements used for validation ocean colour products. Ten measurement systems were compared. Prior intercomparison, absolute radiometric calibration all sensors carried out using same standards methods reference laboratory. Measurements performed under clear sky conditions, relatively low sun zenith...
Currently, water monitoring programs are mainly based on in situ measurements; however, this approach is time-consuming, expensive, and may not reflect the status of whole body. The availability Multispectral Imager (MSI) Ocean Land Colour Instrument (OLCI) free data with high spectral, spatial, temporal resolution has increased potential adding remote sensing techniques into programs, leading to improvement quality water. This study introduced an optical type guided for boreal regions...
A radiometric field intercomparison was conducted at the Acqua Alta Oceanographic Tower (AAOT) in Adriatic Sea from 14 to 21 July 2022 assess differences accuracy of above-water radiometer systems (Sea-Bird HyperSAS, pySAS, TriOS-RAMSES) processed using an open-source community processor (HyperCP). Class-based and sensor-specific characteristics radiometers were used determine quantities Ed(λ), Lsky(λ), Lt(λ) Rrs(λ), their associated uncertainties. Using characteristics, among 2% for 2.5%...
Abstract. A hyperspectral reflectance database was acquired for Baltic Sea submerged aquatic vegetation (SAV) and bare substrates by using Ramses (TriOS GmbH, Germany) radiometers capturing spectral data within the visible (VIS) near-infrared (NIR) ranges. The target samples included most dominant characteristic SAV species in Sea, as well several substrate types beach cast communities. Target were measured 350–900 nm wavelength range under sunlight conditions without water column influence....
An intercomparison of radiance and irradiance ocean color radiometers (the second laboratory comparison exercise—LCE-2) was organized within the frame European Space Agency funded project Fiducial Reference Measurements for Satellite Ocean Color (FRM4SOC) May 8–13, 2017 at Tartu Observatory, Estonia. LCE-2 consisted three sub-tasks: (1) SI-traceable radiometric calibration all participating Observatory just before comparisons; (2) indoor, using stable sources in a controlled environment; (3)...
The Sentinel-3 mission launched its first satellite Sentinel-3A in 2016 to be followed by Sentinel-3B and Sentinel-3C provide long-term operational measurements over Earth. 3B are full status, allowing global coverage less than two days, usable monitor optical water quality data for environmental studies. However, due limited ground truth data, the product has not yet been analyzed detail with fiducial reference measurement (FRM) dataset. Here, we use fully characterized FRM dataset...
An intercomparison of radiance and irradiance ocean color radiometers (The Second Laboratory Comparison Exercise—LCE-2) was organized within the frame European Space Agency funded project Fiducial Reference Measurements for Satellite Ocean Color (FRM4SOC) May 8–13, 2017 at Tartu Observatory, Estonia. LCE-2 consisted three sub-tasks: 1) SI-traceable radiometric calibration all participating Observatory just before comparisons; 2) Indoor using stable sources in controlled environment; 3)...
Abstract. A hyperspectral reflectance database was acquired for the Baltic Sea submerged aquatic vegetation (SAV) and bare substrates by using Ramses (TriOS) radiometers capturing spectral data within visible (VIS) near infrared (NIR) range. The target samples included most dominant characteristic SAV species in Sea, as well several substrate types beach cast communities. Target were measured 350 to 900 nm wavelength range under sun light conditions without water column influence i.e. taken...
Benthic habitats and changes in them are indicators of coastal water quality. Bathymetry is nearly impossible to measure with conventional methods (sonar on a ship) shallow (less than 3-4 m) due high damage risk for the ship instruments. Both depth bottom type critical information environmental monitoring, maritime spatial planning managing waters. Airborne remote sensing can solve problem provide necessary information. However, covering very large areas airborne sensors quite expensive. ESA...
Modifications in submerged aquatic vegetation (SAV) spatial and temporal abundance patterns indicate changes marine environmental conditions or physical disturbances need to be monitored. Vegetation percent cover (%cover) is recognized as one of the key parameters SAV monitoring. Coastal waters Baltic Sea are often turbid contain high amount colored dissolved organic matter. These factors significantly reduce water depth, where benthic can detected by remote sensing. Field campaigns were...
Accurate determination of the water depth and benthic macroalgae composition in coastal inland bodies is important due to high commercial ecological value these regions. Benthic habitat mapping by conventional methods provides good accuracy, but are very expensive limited manpower time factor, which necessary for large areas. Remote sensing significantly complement contact measurements give additional information about hard-to-reach The usefulness free Sentinel-2 data bathymetry has been...
Remote sensing has proved to be an accurate and reliable tool in clear water environments like oceans or the Mediterranean Sea. However, current algorithms methods usually fail on optically complex waters coastal inland waters. The whole Baltic Sea can considered as assessment of quality parameters (eg., chlorophyll-a concentration) is interest for monitoring marine environment, but hasn't been used a routine approach Latvia. In this study, two simultaneous hyperspectral airborne data situ...
It is very hard to discriminate PFGs in optically complex waters even if hyperspectral data available. Features characteristic one group may be sometimes observed reflectance of other phytoplankton groups. Reflectance depends on phenology, biomass and vertical distribution making spectra a single variable.