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Wyświetlanie 1-9 z 9
Tytuł:
Validation of empirical and semi-analytical remote sensing algorithms for estimating absorption by Coloured Dissolved Organic Matter in the Baltic Sea from SeaWiFS and MODIS imagery
Autorzy:
Kowalczuk, P.
Darecki, M.
Zablocka, M.
Gorecka, I.
Powiązania:
https://bibliotekanauki.pl/articles/47876.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
validation
remote sensing
Ocean colour
satellite validation
coloured dissolved organic matter
organic matter
absorption
Baltic Sea
Gdansk Gulf
Vistula River
Opis:
An extensive bio-optical data set obtained from field measurements was used to evaluate the performance of an empirical (Kowalczuk et al. 2005) and two semi- analytical algorithms: Carder et al. (1999) and GSM01 (Maritorena et al. 2002) for estimating CDOM absorption in the Baltic Sea. The data set includes coincident measurements of radiometric quantities and absorption coefficients of CDOM made during 43 cruises between 2000 and 2008. In the first stage of the analysis, the accuracy of the empirical algorithm by Kowalczuk et al. (2005) was assessed using in situ measurements of remote sensing reflectance. Validation results improved when matching points located in Gulf of Gdańsk close to the Vistula River mouth were eliminated from the data set. The calculated errors in the estimation of aCDOM(400) in the first phase of the analysis were Bias = −0.02, RMSE = 0.46 and R2 = 0.70. In the second stage, the empirical algorithm was tested on satellite data from SeaWiFS and MODIS imagery. The satellite data were corrected atmospherically with the MUMM algorithm designed for turbid coastal and inland waters and implemented in the SeaDAS software. The results of the best case scenario for estimating the CDOM absorption coefficient aCDOM(400), based on SeaWiFS data, were Bias = −0.02, RMSE = 0.23 and R2 = 0.40. The validation of the Kowalczuk et al. (2005) empirical algorithm applied to MODIS data led to a less accurate estimate of aCDOM(400): Bias = −0.03, RMSE = 0.19 and R2 = 0.29. This assessment of the accuracy of standard semi-analytical algorithms available in the SeaWiFS and MODIS imagery processing software revealed that both algorithms (GSM 01 and Carder) underestimate CDOM absorption in the Baltic Sea with mean systematic and random errors in excess of 70%. The paper presents examples of the application of the Kowalczuk et al. (2005) empirical algorithm for producing maps of the seasonal distribution of aCDOM(400) in the Baltic Sea between 2004 and 2008.
Źródło:
Oceanologia; 2010, 52, 2; 171-196
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Validation of the hydrodynamic part of the ecohydrodynamic model for the Southern Baltic
Autorzy:
Jedrasik, J.
Powiązania:
https://bibliotekanauki.pl/articles/48134.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
fluctuation
water temperature
hydrodynamic model
validation
sea level
ecohydrodynamic model
salinity
Baltic Sea
Opis:
The first part of the Baltic Sea ecohydrodynamic model, based on the Princeton Ocean Model (POM), was validated by long-term observations of sea level, salinity and water temperature fluctuations. The modelled sea surface temperature (SST) fields were also compared to satellite images – satisfactory correlation coefficients were obtained. The model bias and efficiency coefficients of the modelled variables in relation to the observed values were determined. The quality of model simulations in relation to measured values was estimated with respect to spatial and seasonal variability in shallow and deep coastal waters as well as in the open sea. The results indicated the high quality of simulations by the hydrodynamic model.
Źródło:
Oceanologia; 2005, 47, 4
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Validation of phosphorus compounds in seawater
Walidacja związków fosforu w wodzie morskiej
Autorzy:
Stasiek, K.
Podwojewska, E.
Dembska, G.
Pazikowska-Sapota, G.
Galer-Tatarowicz, K.
Powiązania:
https://bibliotekanauki.pl/articles/111565.pdf
Data publikacji:
2015
Wydawca:
Instytut Morski w Gdańsku
Tematy:
phosphorus
phosphates
nutrients
Baltic Sea
validation
fosfor
fosforany
biogeny
substancje odżywcze
Morze Bałtyckie
walidacja
Opis:
Phosphorus and phosphates, which determine biological development of organisms, are very important components of seawater. Their concentration in the coastal waters of the Baltic Sea is very low, which means that either an analysis of the samples should be performed within a 2 hour limit, or, they must be frozen immediately for further investigation [4; 6; 7]. If it is not possible to perform the analysis of the samples immediately, they should be frozen and shielded from solar radiation in order to halt the biological and biochemical processes. Such a procedure of using the samples, calls for a research method characterized by a low level of the lower limit of quantification, as well as adequate precision, repeatability, and accuracy. The aim of the carried out validation was to confirm the applicability of the method for determination of phosphorus compounds (total phosphorus, phosphates) in seawater for commercial purposes, in accordance with the recommendations of HELCOM [1; 6]. Within the scope of this work, the lower limit of quantification was determined, and the precision, repeatability, accuracy, and reproducibility were identified. The studies confirm that the requirements for validation of the research methods were met.
Fosfor oraz fosforany są bardzo ważnym składnikiem wody morskiej warunkującym biologiczny rozwój organizmów. Ich stężenia w wodach przybrzeżnych Morza Bałtyckiego są bardzo małe, dlatego należy wykonać analizę próbek najpóźniej do 2 godzin po pobraniu lub natychmiast zamrozić próbki w celu dokonania późniejszych oznaczeń [4; 6; 7]. Jeśli nie jest możliwe natychmiastowe wykonanie analizy próbek należy je zamrozić oraz zabezpieczyć przed światłem słonecznym w celu zatrzymania procesów biologicznych i biochemicznych. Taka procedura postępowania z próbką wymaga metody badawczej o niskiej dolnej granicy oznaczalności oraz odpowiedniej precyzji, powtarzalności i dokładności. Celem przeprowadzonej walidacji było potwierdzenie możliwości stosowania metody oznaczania zawartości związków fosforu (fosfor ogólny, fosforany) w wodzie morskiej do celów komercyjnych zgodnie z zaleceniami HELCOM [1; 6]. W ramach niniejszej pracy wyznaczono dolną granicę oznaczalności, określono precyzję, powtarzalność, dokładność oraz odtwarzalność. Przeprowadzone badania potwierdzają spełnienie wymagań dotyczących walidacji metod badawczych.
Źródło:
Biuletyn Instytutu Morskiego w Gdańsku; 2015, 30, 1; 126-130
1230-7424
2450-5536
Pojawia się w:
Biuletyn Instytutu Morskiego w Gdańsku
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ecohydrodynamic model of the Baltic Sea. Part 2. Validation of the model
Autorzy:
Jedrasik, J.
Szymelfenig, M.
Powiązania:
https://bibliotekanauki.pl/articles/47717.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
organic matter
production
nutrient
destruction
mineralization
validation
ProDeMo model
ecohydrodynamic model
Baltic Sea
algal bloom
Opis:
The ecohydrodynamic model for the Baltic Sea consists of two interacting parts: one describes the hydrodynamics of the water (3HD), the other organic matter production and destruction (ProDeMo).The results of the simulation were validated.The modelled processes were compared with direct observations, which demonstrated the recurrence of cycles, from the spring diatom blooms through the summer depletion of nutrient salts and algal blooms, to autumn blooms of diatoms and the subsequent destruction of organic matter, and intensified mineralisation of detritus in winter.Ca libration yielded a set of coefficients complementing the algorithm of equations describing the production and destruction of organic matter in the coastal zone.V erification of the model has demonstrated that in multi-year simulations it is stable and also that it follows the laws of conservation of mass and energy.T he third procedural stage of the model investigation was validation, in which statistical measures in the form of bias, correlation coefficients and effectiveness between simulations and observations not used in calibration describe the quality of ecohydrodynamic modelling in southern Baltic Sea waters.
Źródło:
Oceanologia; 2005, 47, 4
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of the Hel upwelling (Baltic Sea) on nutrient concentrations and primary production - the results of an ecohydrodynamic model
Autorzy:
Kowalewski, M.
Powiązania:
https://bibliotekanauki.pl/articles/49109.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
primary production
nutrient concentration
phytoplankton biomass
ecohydrodynamic modelling
upwelling
validation
ProDeMo model
Baltic Sea
Gdansk Gulf
Opis:
An ecohydrodynamic model was used to investigate the effect of the Hel upwelling on nutrient concentrations, primary production and phytoplankton biomass. The model covered the whole Baltic Sea with a 5 NM grid spacing and the Gulf of Gdańskwith a 1 NM grid spacing. Validation indicated good agreement between model results and measurements in the GdańskD eep, and slightly weaker concord for the Hel upwelling area. The vertical nutrient fluxes associated with up- and downwelling in the Hel region were simulated for two 30-day periods in 2000. The nutrient input resulting from long-term upwelling is comparable to the load carried into the Gulf of Gdańskb y the Vistula (Wisła), the largest river in the vicinity. Performed at times when upwelling was almost permanent, the simulations showed elevated nutrient concentrations in surface waters. This was especially distinct in spring when primary production and phytoplankton biomass were both higher. In late summer, however, upwelling caused primary production to decrease, despite the elevated nutrient levels.
Źródło:
Oceanologia; 2005, 47, 4
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fluorescence measured in situ as a proxy of CDOM absorption and DOC concentration in the Baltic Sea
Autorzy:
Kowalczuk, P.
Zablocka, M.
Sagan, S.
Kulinski, K.
Powiązania:
https://bibliotekanauki.pl/articles/48318.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
Baltic Sea
measurement
optical property
dissolved organic carbon
concentration
dissolved organic matter
fluorescence
global climate model
validation
Źródło:
Oceanologia; 2010, 52, 3; 431-471
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
In situ measurements and satellite remote sensing of case 2 waters: first results from the Curonian Lagoon
Autorzy:
Giardino, C.
Bresciani, M.
Pilkaityte, R.
Bartoli, M.
Razinkovas, A.
Powiązania:
https://bibliotekanauki.pl/articles/48042.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
satellite remote sensing
satellite image
water
Curonian Lagoon
eutrophication
calibration
validation
eutrophic ecosystem
aquatic ecosystem
Baltic Sea
Opis:
In this study we present calibration/validation activities associated with satellite MERIS image processing and aimed at estimating chl a and CDOM in the Curonian Lagoon. Field data were used to validate the performances of two atmospheric correction algorithms, to build a band-ratio algorithm for chl a and to validate MERIS-derived maps. The neural network-based Case 2 Regional processor was found suitable for mapping CDOM; for chl a the band-ratio algorithm applied to image data corrected with the 6S code was found more appropriate. Maps were in agreement with in situ measurements. This study confirmed the importance of atmospheric correction to estimate water quality and demonstrated the usefulness of MERIS in investigating eutrophic aquatic ecosystems.
Źródło:
Oceanologia; 2010, 52, 2; 197-210
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Particulate organic carbon in the Southern Baltic Sea: numerical simulations and experimental data
Autorzy:
Dzierzbicka-Glowacka, L.
Kulinski, K.
Maciejewska, A.
Jakacki, J.
Pempkowiak, J.
Powiązania:
https://bibliotekanauki.pl/articles/48082.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
Baltic Sea
Gdansk Deep
calcification
carbon cycle
detritus
nutrient
organic compound
organic matter
particulate organic carbon
photosynthesis
phytoplankton
primary production
sea water
validation
zooplankton
Opis:
Particulate Organic Carbon (POC) is an important component in the carbon cycle of land-locked seas. In this paper, we assess the POC concentration in the Gdańsk Deep, southern Baltic Sea. Our study is based on both a 1D POC Model and current POC concentration measurements. The aim is twofold: (i) validation of simulated concentrations with actual measurements, and (ii) a qualitative assessment of the sources contributing to the POC pool. The POC model consists of six coupled equations: five diffusion-type equations for phytoplankton, zooplankton, pelagic detritus and nutrients (phosphate and total inorganic nitrogen) and one ordinary differential equation for detritus at the bottom. The POC concentration is determined as the sum of phytoplankton, zoo-plankton and pelagic detritus concentrations, all expressed in carbon equivalents. Bacteria are not simulated in this paper. The observed large fluctuations of POC concentrations are attributed to its appreciable seasonal variability. The maximum concentration of POC varied between 870 mgC m−3 in May and 580 mgC m−3 in September, coinciding with the period of maximum dead organic matter and phytoplankton biomass concentrations. The results of the numerical simulations are in good agreement with observed values. The difference between the modelled and observed POC concentrations is equal to 3–28% and depends on the month for which the calculations were made, although no time trend of the difference is observed. The conclusion is that the numerical simulations are a ufficiently good reflection of POC dynamics in the Baltic.
Źródło:
Oceanologia; 2010, 52, 4
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improvement of MERIS level 2 products in Baltic Sea coastal areas by applying the Improved Contrast between Ocean and Land processor (ICOL) - data analysis and validation
Autorzy:
Kratzer, S.
Vinterhav, C.
Powiązania:
https://bibliotekanauki.pl/articles/48296.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
MERIS standard processor
FUB processor
C2E process
Baltic Sea
coastal area
data analysis
validation
spectral reflectance
open sea
remote sensing
water quality
atmosphere
water body
total suspended matter
suspended particulate matter
organic matter
Opis:
In this paper we compare the following MERIS processors against sea-truthing data: the standard MERIS processor (MEGS 7.4.1), the Case 2 Regional processor (C2R) of the German Institute for Coastal Research (GKSS), and the Case 2Water Properties processor developed at the Freie Universit¨at Berlin (FUB). Furthermore, the Improved Contrast between Ocean and Land processor (ICOL), a prototype processor for the correction of adjacency effects from land, was tested on all three processors, and the retrieval of level 2 data was evaluated against sea-truthing data before and after ICOL processing. The results show that by using ICOL the retrieval of spectral reflectance in the open sea was improved for all processors. After ICOL processing, the FUB showed rather small errors in the blue, but underestimated in the red −34% Mean Normalised Bias (MNB) and 37% Root Mean Square (RMS). For MEGS the reflectance in the red was underestimated by about −20% MNB and 23% RMS, whereas the reflectance in the other channels was well predicted, even without any ICOL processing. The C2R underestimated the red with about −27% MNB and 29% RMS and at 412 nm it overestimated the reflectance with about 23% MNB and 29% RMS. At the outer open sea stations ICOL processing did not have a strong effect: the effect of the processor diminishes progressively up to 30 km from land. At the open sea stations the ICOL processor improved chlorophyll retrieval using MEGS from −74% to about 34% MNB, and TSM retrieval from −63% to about 22% MNB. Using FUB in combination with ICOL gave even better results for both chlorophyll (25% MNB and 45% RMS) and TSM (−4% MNB and 36% RMS) in the open Baltic Sea. All three processors predicted TSM rather well, but the standard processor gave the best results (−12% MNB and 17% RMS). The C2R had a very low MNB for TSM (1%), but a rather high RMS (54%). The FUB was intermediate with −16% MNB and 31% RMS. In coastal waters, the spectral diffuse attenuation coefficient Kd(490) was well predicted using FUB or MEGS in combination with ICOL (MNB about 12% for FUB and 0.4% for MEGS). Chlorophyll was rather well predicted in the open Baltic Sea using FUB with ICOL (MNB 25%) and even without ICOL processing (MNB about 15%). ICOL-processed MEGS data also gave rather good retrieval of chlorophyll in the coastal areas (MNB of 19% and RMS of 28%). In the open Baltic Sea chlorophyll retrieval gave a MNB of 34% and RMS of 70%, which may be due to the considerable patchiness caused by cyanobacterial blooms. The results presented here indicate that with the MERIS mission, ESA and co- workers are in the process of solving some of the main issues regarding the remote sensing of coastal waters: spatial resolution; land-water adjacency effects; improved level 2 product retrieval in the Baltic Sea, i.e. the retrieval of spectral reflectance and of the water quality products TSM and chlorophyll.
Źródło:
Oceanologia; 2010, 52, 2; 211-236
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-9 z 9

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