scholarly journals Prewhitened causality analysis for the chlorophyll-a concentration in the Yeongsan River system

2018 ◽  
Vol 54 (2) ◽  
pp. 161-177 ◽  
Author(s):  
Eunhyung Lee ◽  
Sanghyun Kim ◽  
Eunhye Na ◽  
Kyunghyun Kim
Keyword(s):  
Water Quality ◽  
Factor Analysis ◽  
Chlorophyll A ◽  
Cross Correlation ◽  
River System ◽  
River Regulation ◽  
Principal Factor ◽  
Principal Factor Analysis ◽  
Chl A ◽  
The Impact

Abstract Blooming of algae has been a primary issue of concern for heavily polluted aquatic ecosystems. The chlorophyll-a (Chl-a) concentration depends on various hydrological, biochemical and anthropogenic components, which makes prediction of algal blooms complicated. A river regulation project in Yeongsan River, South Korea, involving the construction of a weir, had substantially altered the flow regime. A prewhitened time series analysis is a useful method for delineation of a causal relationship between two environmental variables. This study explores the impact of river regulation on algal blooming using both the prewhitened cross-correlation method and principal factor analysis. Both individual and comprehensive causality structures were configured for the variation in Chl-a concentration. A prewhitened cross-correlation analysis indicates that the water quality response patterns of the river system were changed to those of a reservoir after the river regulation project. A principal factor analysis of correlations indicates that the weir construction had a stronger impact on algal concentration than both the hydro-meteorological factor and difference in sampling location. Variation in stochastic structures from nutrients and water quality factors to algal bloom was substantially reduced by the construction of a weir, which can be explained by the relatively uniform flow pattern throughout the river regulation practice.

Use of principal factor analysis to generate a corn silage fermentative quality index to rank well- or poorly preserved forages

2015 ◽  
Vol 96 (5) ◽  
pp. 1686-1696 ◽  
Author(s):  
Antonio Gallo ◽  
Gianluca Giuberti ◽  
Sara Bruschi ◽  
Paola Fortunati ◽  
Francesco Masoero
Keyword(s):  
Factor Analysis ◽  
Quality Index ◽  
Principal Factor ◽  
Corn Silage ◽  
Principal Factor Analysis

scholarly journals Temporal Variation of Chlorophyll-a Concentrations in Highly Dynamic Waters from Unattended Sensors and Remote Sensing Observations

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2699 ◽  
Author(s):  
Jian Li ◽  
Liqiao Tian ◽  
Qingjun Song ◽  
Zhaohua Sun ◽  
Hongjing Yu ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Water Quality ◽  
Chlorophyll Fluorescence ◽  
Chlorophyll A ◽  
Temporal Variations ◽  
Lake Area ◽  
Short Term ◽  
Chl A ◽  
Spatio Temporal

Monitoring of water quality changes in highly dynamic inland lakes is frequently impeded by insufficient spatial and temporal coverage, for both field surveys and remote sensing methods. To track short-term variations of chlorophyll fluorescence and chlorophyll-a concentrations in Poyang Lake, the largest freshwater lake in China, high-frequency, in-situ, measurements were collected from two fixed stations. The K-mean clustering method was also applied to identify clusters with similar spatio-temporal variations, using remote sensing Chl-a data products from the MERIS satellite, taken from 2003 to 2012. Four lake area classes were obtained with distinct spatio-temporal patterns, two of which were selected for in situ measurement. Distinct daily periodic variations were observed, with peaks at approximately 3:00 PM and troughs at night or early morning. Short-term variations of chlorophyll fluorescence and Chl-a levels were revealed, with a maximum intra-diurnal ratio of 5.1 and inter-diurnal ratio of 7.4, respectively. Using geostatistical analysis, the temporal range of chlorophyll fluorescence and corresponding Chl-a variations was determined to be 9.6 h, which indicates that there is a temporal discrepancy between Chl-a variations and the sampling frequency of current satellite missions. An analysis of the optimal sampling strategies demonstrated that the influence of the sampling time on the mean Chl-a concentrations observed was higher than 25%, and the uncertainty of any single Terra/MODIS or Aqua/MODIS observation was approximately 15%. Therefore, sampling twice a day is essential to resolve Chl-a variations with a bias level of 10% or less. The results highlight short-term variations of critical water quality parameters in freshwater, and they help identify specific design requirements for geostationary earth observation missions, so that they can better address the challenges of monitoring complex coastal and inland environments around the world.

scholarly journals Effects of Weir Construction on Phytoplankton Assemblages and Water Quality in a Large River System

2018 ◽  
Vol 15 (11) ◽  
pp. 2348 ◽  
Author(s):  
Hae-Jin Lee ◽  
Hae-Kyung Park ◽  
Se-Uk Cheon
Keyword(s):  
Water Quality ◽  
Chlorophyll A ◽  
River System ◽  
Large River ◽  
Anthropogenic Factors ◽  
Centric Diatom ◽  
Nakdong River ◽  
Biological Variables ◽  
Physical Chemical ◽  
The Nakdong River

Flow regulation is one of the most common anthropogenic factors affecting rivers worldwide. In Korea, 16 weirs were constructed along four major rivers from 2009 to 2012. This study aimed to elucidate initial changes in physical, chemical, and biological variables after the construction of consecutive weirs on the Nakdong River, a major large river system. Water quality variables and phytoplankton cell densities were investigated at eight representative sites and compared with the data recorded before the weir construction. There were spatial and temporal changes in the hydraulic retention time (HRT), total phosphorus (TP), and chlorophyll a concentrations among the eight weir sections. HRT increased after the weir construction, while TP and chlorophyll a tended to decrease from the middle to lower section of the Nakdong River. Furthermore, differences were observed in the phytoplankton community composition between 2006–2007 and 2013. There was a marginal decrease in the duration of centric diatom (Stephanodiscus hantzschii) blooms after weir construction. However, Microcystis aeruginosa proliferated more extensively during summer and autumn than it did before the weir construction. Our results suggest that changes in hydrological factors, in response to consecutive weir construction, may contribute to greater physical, chemical, and ecological variability.

scholarly journals Retraction: Jelic-Mrcelic G, Sliskovic M. The evaluation of fish farming impact by nutrient content and chlorophyll a in Mala Lamljana bay. Arch biol sci. 2013;65(2):567-70. DOI: 10.2298/ABS1302567J

2015 ◽  
Vol 67 (4) ◽  
pp. 1437-1437
Author(s):  
E Editorial
Keyword(s):  
Biological Sciences ◽  
Water Quality ◽  
Chlorophyll A ◽  
Fish Farming ◽  
Nutrient Content ◽  
Fish Farm ◽  
Significant Part ◽  
Retracted Article ◽  
The Impact ◽  
Font Color

This is a notice of retraction of the article: The evaluation of fish farming impact by nutrient content and chlorophyll A in Mala Lamljana bay, published in the Archives of Biological Sciences in 2013, Vol. 65, Issue 3. The Editor-in-Chief has been informed that the data in this article has already been published in the following article: Jelic Mrcelic G, Sliskovic M. The impact of fish cages on water quality in one fish farm in Croatia. Int Sci Index. 2010;4(8):775-8. Inspection of these articles has revealed the following: a significant part of the data in the article published in the Archives of Biological Sciences was published without proper cross-referencing to the data already published in the earlier paper. This issue was discussed with one of the two authors and it was mutually agreed to retract the article. <br><br><font color="red"><b> Link to the retracted article <u><a href="http://dx.doi.org/10.2298/ABS1302567J">10.2298/ABS1302567J</a></b></u>

scholarly journals STUDY ON CYCLONE INDUCED PHYTOPLANKTON BLOOM IN THE ARABIAN SEA THROUGH GAP-FREE RECONSTRUCTED CHLOROPHYLL-A DATA

2020 ◽  
Vol XLIII-B3-2020 ◽  
pp. 1391-1396
Author(s):  
R. Shunmugapandi ◽  
S. Gedam ◽  
A. B. Inamdar
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Chlorophyll A ◽  
Arabian Sea ◽  
Phytoplankton Bloom ◽  
Suitable Condition ◽  
Sea Surface ◽  
Cyclone Track ◽  
Chl A ◽  
The Impact

Abstract. Ocean surface phytoplankton responses to the tropical cyclone (TC)/storms have been extensively studied using satellite observations by aggregating the data into a weekly or bi-weekly composite. The reason behind is the significant limitations found in the satellite-based observation is the missing of valid data due to cloud cover, especially at the time of cyclone track passage. The data loss during the cyclone is found to be a significant barrier to efficiently investigate the response of chl-a and SST during cyclone track passage. Therefore it is necessary to rectify the above limitation to effectively study the impact of TC on the chlorophyll-a concentration (chl-a) and the sea surface temperature (SST) to achieve a complete understanding of their response to the TC prevailed in the Arabian Sea. Intending to resolve the limitation mentioned above, this study aims to reconstruct the MODIS-Aqua chl-a, and SST data using Data Interpolating Empirical Orthogonal Function (DINEOF) for all the 31 cyclonic events occurred in the Arabian Sea during 2003-2018 (16 years). Reconstructed satellite retrieved data covering all the cyclonic events were further used to investigate the chl-a and SST dynamics during TC. From the results, the exciting fact has been identified that only two TC over the eastern-AS were able to induce phytoplankton bloom. On investigating this scenario using sea surface temperature, it was disclosed that the availability of nutrients decides the suitable condition for the phytoplankton to proliferate in the surface ocean. Relevant to the precedent criterion, the results witnessed that the 2 TC (Phyan and Ockhi cyclone) prevailed in the eastern AS invoked a suitable condition for phytoplankton bloom. Other TC found to be less provocative either due to less intensity, origination region or the unsuitable condition. Thereby, gap-free reconstructed daily satellite-derived data efficiently investigates the response of bio-geophysical parameters during cyclonic events. Moreover, this study sensitised that though several TC strikes the AS, only two could impact phytoplankton productivity and SST found to highly consistent with the chl-a variability during the cyclone passage.

scholarly journals Study on the Causes of Water Environmental Pollution of Important Rivers in Haihe River Basin and Countermeasures

2021 ◽  
Vol 261 ◽  
pp. 04023
Author(s):  
Xu He ◽  
Hou Siyan
Keyword(s):  
Water Quality ◽  
Point Source ◽  
Environmental Pollution ◽  
River Basin ◽  
River Regulation ◽  
Haihe River Basin ◽  
Point Source Pollution ◽  
Haihe River ◽  
The Impact

The water quality of six important rivers in Haihe River Basin, including Yongding River, Luanhe River, North Canal, Daqing River, South Canal and Chaobai River, was evaluated. The influence of point source and non-point source on water quality was analyzed. The causes of water environmental pollution in the major rivers were preliminarily revealed. The results show that the water quality of Chaobai River is good, and the impact of point source and non-point source discharge on the water body is small. Other rivers are affected by different degrees of point source and non-point source pollution. Based on the analysis results, the engineering measures and management countermeasures for river regulation are put forward.

A robust version of principal factor analysis

COMPSTAT ◽  
2000 ◽  
pp. 385-390 ◽  
Author(s):  
G. Pison ◽  
P. J. Rousseeuw ◽  
P. Filzmoser ◽  
C. Croux
Keyword(s):  
Factor Analysis ◽  
Principal Factor ◽  
Principal Factor Analysis ◽  
Robust Version
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