1,721,021 research outputs found
Reflectance spectra of submerged aquatic vegetation (SAV) species and substrates from the Baltic Sea coastal waters
No full textThis project measured spectral reflectance for variety of submerged aquatic vegetation (SAV) species and bare substrate types found in Estonia and Swedish coastal waters in the Baltic Sea. The dataset was collected between 2011-2012 during various field campaigns. Target samples were measured within the 350 to 900 nm wavelength range under sun light conditions using Ramses (TriOS GmbH, Germany) measurement set, which consisted of two simultaneously operated sensors: irradiance and radiance sensors. The radiance sensor measured upwelling spectral radiance Lu (W m-2 nm-1 sr-1) and irradiance sensor measured downwelling spectral irradiance Ed (W m-2 nm-1). Remote sensing reflectance (Rrs) was calculated as the ratio of Lu/Ed (sr-1). All target samples were taken out of the water before the measurement
Carbon fractions (TOC, DOC, DIC) measured from coastal waters of the Baltic Sea in 2023–2024
No full textThis dataset contains in situ measurements of carbon fractions—Dissolved Inorganic Carbon (DIC), Dissolved Organic Carbon (DOC), and Total Organic Carbon (TOC). In 2023 and 2024, we collected data from the coastal waters of the northern Baltic Sea in the frame of seasonal field campaigns. These campaigns were timed to capture a variety of biogeochemical and environmental conditions. The collected data provide insights into the distribution of organic and inorganic carbon in coastal waters, supporting applications such as marine carbon budget assessments, climate change research, and coastal ecosystem studies, as well as the validation of satellite-derived products and the improvement of coastal biogeochemical models in optically complex waters like the Baltic Sea. Water samples were collected from surface waters from various locations, and all carbon fraction analyses were conducted in accordance with EVS-EN 1484, and a Vario TOC analyser (Elementar GmbH, Germany) was used. DOC and DIC were measured from 0.45 µm filtered samples
Spectral reflectance and associated water quality parameters measured from coastal waters of the Baltic Sea in 2023–2024
No full textThe dataset contains in situ measurements of remote sensing reflectance (Rrs, sr⁻¹) and associated water quality parameters like coloured dissolved organic matter absorption (aCDOM), total suspended matter (TSM), suspended particulate inorganic matter (SPIM), suspended particulate organic matter (SPOM), and chlorophyll-a (Chl-a). In 2023 and 2024, we collected data from the coastal waters of the northern Baltic Sea in the frame of seasonal field campaigns. These campaigns were timed to capture a variety of environmental and optical conditions. This dataset can be used, for example, for the development and validation of satellite-based retrieval algorithms, improving our understanding of the optical properties of coastal waters, and studying biogeochemical processes in these complex environments. Water reflectance was measured with two (downwelling spectral irradiance, Ed; upwelling spectral radiance, Lu) Ramses (TriOS GmbH) spectrophotometers. "Glint-free" reflectance measurements were carried out, lowering the plastic tube, which surrounds the regular TriOS Ramses Lu sensor, just below the water surface. These glint-free reflectance values are brought out in the dataset. Water samples collected simultaneously with the optical measurements were analysed in the laboratory. TSM, SPIM, and SPOM were determined using the gravimetric method, in which a water suspension is filtered through a pre-weighed microfibre filter to determine the mass of particles retained on the filter. aCDOM spectra were measured from filtered (0.2 µm) water spectrophotometrically, using Milli-Q water as a reference. Chl-a concentration was determined using a spectrophotometric method based on pigment extraction with acetone and absorbance measurement in the visible range. Each water sample was analysed in two parallel replicates to improve reliability and enable quality control
The possibility of using the Landsat image archive for monitoring long time trends in coloured dissolved organic matter concentration in lake waters
No full textRecent studies indicate that lakes are regulators of carbon cycling and climate. Therefore, it is important to know how the lake carbon content has changed over the last decades. In situ long time data series about the amount of dissolved organic carbon (DOC) in lakes are rare. The only potential way to study retrospectively the changes in lake carbon over the last decades is by means of remote sensing data provided there are sensors that can provide data about coloured dissolved organic matter (CDOM) in lakes over long periods. Landsat data archive contains images from 1984 to nowadays and covers the whole Earth. Although the sensors were not designed for remote sensing of aquatic environments it is still tempting to utilise the long data series. Landsat 4, Landsat 5 and Landsat 7 imagery available in free Landsat image archive was compared with time series of CDOM in situ data from 19 sampling stations available in the Swedish University of Natural Sciences lake monitoring database. There was no correlation between the image and in situ data when all the above mentioned data were used. Low radiometric resolution of the sensor, small size of many lakes (= large adjacency effects) and high concentration of CDOM (negligible water leaving radiation) could be the reasons. The results were more promising (R-2 = 0.62) when Lake Malaren stations were analysed separately. The lake is sufficiently large and with variable, but not extremely high. CDOM content. The Lake Malaren in situ data showed very different trends in CDOM concentrations in different basins of the lake over the last 45 years. Although the correlation between the image and in situ data was a bit low for accurate daily estimation of CDOM concentrations from Landsat data it could allow detecting general trends in lake CDOM content. Unfortunately, there is currently a gap in Landsat archive (for our study sites) between 1988 and 1998 which makes calculations of long time trends unreasonable for the time being. (C) 2012 Elsevier Inc. All rights reserved.</p
Colour and Light in the Ocean
No full textThis eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contac
Report on the checklist for maintaining contact with individuals taking family breaks
Full text linkThe report compiles a checklist that will help to maintain contacts with the individuals taking family breaks and for employees returning to regular working conditions afterwards. Binding procedures will be recommended to guarantee a successful career continuation with continuous institutional support
Deliverable 2.2.1. Improved chlorophyll-a algorithm
No full textFütoplanktoni biomass on üks põhilisi veekogude eutrofeerumise indikaatoreid. Kõige levinum
parameeter, mille abil fütoplanktoni biomassi hinnatakse on planktonis leiduva pigmendi klorofüll-a
kontsentratsioon. Mõõtmiste tegemine merel on kallis ja aeganõudev. Uurimislaeva päev võib maksta
kümneid tuhandeid eurosid, laeval töötab tihti kümneid inimesi, aga samas on ühe päeva jooksul
uuritavate mõõtejaamade hulk äärmiselt piiratud (enamasti vaid mõned jaamad päevas). Peale selle,
võtab kogutud proovide analüüs laboris tihti veel nädalaid. Samas võib meri olla nii ajas kui ruumis
väga dünaamiline. Näiteks õitsengutes või kaldalähedastes vetes võivad vee omaduse juba mõnisada
(või isegi mõnikümmend) meetrit mõõtejaamast eemal, või mõni tund enne või pärast mõõtmisi, olla
oluliselt erinevad kui jaamas kogutud veeproovis. Seda ei saa me kunagi teada. Seiremõõtmisi
teostatakse ka vaid mõned korrad aastas väga piiratud hulgas mõõtejaamades, sest see töö on väga
ajamahukas ja kallis. Mis toimub meres seiremõõtmiste vahepeal jääb meile laevalt tehtavate
mõõtmiste puhul teadmata
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