scholarly journals Assessing Phytoplankton Bloom Phenology in Upwelling-Influenced Regions Using Ocean Color Remote Sensing

2021 ◽  
Vol 13 (4) ◽  
pp. 675
Author(s):  
Afonso Ferreira ◽  
Vanda Brotas ◽  
Carla Palma ◽  
Carlos Borges ◽  
Ana C. Brito
Keyword(s):  
Climate Change ◽  
Remote Sensing ◽  
Phytoplankton Bloom ◽  
Ocean Color ◽  
Coastal Region ◽  
Coastal Areas ◽  
Ocean Color Remote Sensing ◽  
Chl A ◽  
Peak Biomass ◽  
Phytoplankton Communities

Phytoplankton bloom phenology studies are fundamental for the understanding of marine ecosystems. Mismatches between fish spawning and plankton peak biomass will become more frequent with climate change, highlighting the need for thorough phenology studies in coastal areas. This study was the first to assess phytoplankton bloom phenology in the Western Iberian Coast (WIC), a complex coastal region in SW Europe, using a multisensor long-term ocean color remote sensing dataset with daily resolution. Using surface chlorophyll a (chl-a) and biogeophysical datasets, five phenoregions (i.e., areas with coherent phenology patterns) were defined. Oceanic phytoplankton communities were seen to form long, low-biomass spring blooms, mainly influenced by atmospheric phenomena and water column conditions. Blooms in northern waters are more akin to the classical spring bloom, while blooms in southern waters typically initiate in late autumn and terminate in late spring. Coastal phytoplankton are characterized by short, high-biomass, highly heterogeneous blooms, as nutrients, sea surface height, and horizontal water transport are essential in shaping phenology. Wind-driven upwelling and riverine input were major factors influencing bloom phenology in the coastal areas. This work is expected to contribute to the management of the WIC and other upwelling systems, particularly under the threat of climate change.

scholarly journals Design and Experiments of a Water Color Remote Sensing-Oriented Unmanned Surface Vehicle

Sensors ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 2183
Author(s):  
Yong Li ◽  
Liqiao Tian ◽  
Wenkai Li ◽  
Jian Li ◽  
Anna Wei ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Data Acquisition ◽  
Obstacle Avoidance ◽  
Ocean Color ◽  
Water Color ◽  
Unmanned Surface Vehicle ◽  
Ocean Color Remote Sensing ◽  
Chl A ◽  
In Situ Observations

Integrated and intelligent in situ observations are important for the remote sensing monitoring of dynamic water environments. To meet the field investigation requirements of ocean color remote sensing, we developed a water color remote sensing-oriented unmanned surface vehicle (WC-USV), which consisted of an unmanned surface vehicle platform with ground control station, data acquisition, and transmission modules. The WC-USV was designed with functions, such as remote controlling, status monitoring, automatic obstacle avoidance, and water and meteorological parameter measurement acquisition, transmission, and processing. The key data acquisition module consisted of four parts: A floating optical buoy (FOBY) for collecting remote sensing reflectance ( R r s ) via the skylight-blocked approach; a water sample autocollection system that can collect 12 1-L bottles for analysis in the laboratory; a water quality measurement system for obtaining water parameters, including Chlorophyll-a (Chl-a), turbidity, and water temperature, among others; and meteorological sensors for measuring wind speed and direction, air pressure, temperature, and humidity. Field experiments were conducted to validate the performance of the WC-USV on 23–28 March 2018 in the Honghu Lake, which is the seventh largest freshwater lake in China. The tests proved the following: (1) The WC-USV performed well in terms of autonomous navigation and obstacle avoidance; (2) the mounted FOBY-derived R r s showed good precision in terms of the quality assurance score (QAS), which was higher than 0.98; (3) the Chl-a and suspended matters (SPM) as ocean color parameters measured by the WC-USV were highly consistent with laboratory analysis results, with determination coefficients (R2) of 0.71 and 0.77, respectively; and (4) meteorological parameters could be continuously and stably measured by WC-USV. Results demonstrated the feasibility and practicability of the WC-USV for automatic in situ observations. The USV provided a new way of thinking for the future development of intelligent automation of the aquatic remote sensing ground verification system. It could be a good option to conduct field investigations for ocean color remote sensing and provide an alternative for highly polluted and/or shallow high-risk waters which large vessels have difficulty reaching.

scholarly journals Special Issue on Remote Sensing of Ocean Color: Theory and Applications

Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3445
Author(s):  
Trevor Platt ◽  
Shubha Sathyendranath ◽  
Heather Bouman ◽  
Carsten Brockmann ◽  
David McKee
Keyword(s):  
Climate Change ◽  
Remote Sensing ◽  
Public Participation ◽  
Ocean Color ◽  
Color Theory ◽  
Editorial Team ◽  
Special Issue ◽  
Ocean Color Remote Sensing

The editorial team are delighted to present this Special Issue of Sensors focused on Remote Sensing of Ocean Color: Theory and Applications. We believe that this is a timely opportunity to showcase current developments across a broad range of topics in ocean color remote sensing (OCRS). Although the field is well-established, in this Special Issue we are able to highlight advances in the applications of the technology, our understanding of the underpinning science, and its relevance in the context of monitoring climate change and engaging public participation.

scholarly journals Global land mask for satellite ocean color remote sensing

2021 ◽  
Vol 257 ◽  
pp. 112356
Author(s):  
Karlis Mikelsons ◽  
Menghua Wang ◽  
Xiao-Long Wang ◽  
Lide Jiang
Keyword(s):  
Remote Sensing ◽  
Ocean Color ◽  
Ocean Color Remote Sensing ◽  
Global Land ◽  
Satellite Ocean Color

scholarly journals Effects of climate change on spatiotemporal patterns of tropical cyclone tracks and their implications for coastal agriculture in Myanmar

2021 ◽  
Author(s):  
Akira Hirano
Keyword(s):  
Climate Change ◽  
Global Warming ◽  
Considerable Increase ◽  
Hot Spot ◽  
Coastal Region ◽  
Storm Surges ◽  
Coastal Areas ◽  
Spatiotemporal Patterns ◽  
Sea Levels ◽  
Rising Sea Levels

AbstractImportant aspects for understanding the effects of climate change on tropical cyclones (TCs) are the frequency of TCs and their tracking patterns. Coastal areas are increasingly threatened by rising sea levels and associated storm surges brought on by TCs. Rice production in Myanmar relies strongly on low-lying coastal areas. This study aims to provide insights into the effects of global warming on TCs and the implications for sustainable development in vulnerable coastal areas in Myanmar. Using TC records from the International Best Track Archive for Climate Stewardship dataset during the 30-year period from 1983 to 2012, a hot spot analysis based on Getis-Ord (Gi*) statistics was conducted to identify the spatiotemporal patterns of TC tracks along the coast of Myanmar. The results revealed notable changes in some areas along the central to southern coasts during the study period. These included a considerable increase in TC tracks (p value < 0.01) near the Ayeyarwady Delta coast, otherwise known as “the rice bowl” of the nation. This finding aligns with trends in published studies and reinforced the observed trends with spatial statistics. With the intensification of TCs due to global warming, such a significant increase in TC experiences near the major rice-producing coastal region raises concerns about future agricultural sustainability.

Effects of Earth curvature on atmospheric correction for ocean color remote sensing

2018 ◽  
Vol 209 ◽  
pp. 118-133 ◽  
Author(s):  
Xianqiang He ◽  
Knut Stamnes ◽  
Yan Bai ◽  
Wei Li ◽  
Difeng Wang
Keyword(s):  
Remote Sensing ◽  
Ocean Color ◽  
Atmospheric Correction ◽  
Ocean Color Remote Sensing

scholarly journals Spatio-Temporal Variability in Bio-Optical Properties of the Southern Caspian Sea: A Historic Analysis of Ocean Color Data

2020 ◽  
Vol 12 (23) ◽  
pp. 3975
Author(s):  
Bonyad Ahmadi ◽  
Mehdi Gholamalifard ◽  
Tiit Kutser ◽  
Stefano Vignudelli ◽  
Andrey Kostianoy
Keyword(s):  
Remote Sensing ◽  
Optical Properties ◽  
Attenuation Coefficient ◽  
Temporal Variability ◽  
Caspian Sea ◽  
Ocean Color ◽  
Time Lags ◽  
Chl A ◽  
Remote Sensing Reflectance ◽  
Southern Caspian Sea

Currently, satellite ocean color imageries play an important role in monitoring of water properties in various oceanic, coastal, and inland ecosystems. Although there is a long-time and global archive of such valuable data, no study has comprehensively used these data to assess the changes in the Caspian Sea. Hence, this study assessed the variability of bio-optical properties of the upper-water column in the Southern Caspian Sea (SCS) using the archive of the Sea-Viewing Wide Field-of-View Sensor (SeaWiFS) and the Moderate Resolution Imaging Spectroradiometer (MODIS). The images acquired from SeaWiFS (January 1998 to December 2002) and MODIS Aqua (January 2003 to December 2015) satellites were used to investigate the spatial–temporal variability of bio-optical properties including Chlorophyll-a (Chl-a), attenuation coefficient, and remote sensing reflectance, and environmental parameters such as sea surface temperature (SST), wind stress and the El Nino-southern oscillation (ENSO) phenomena at different time lags in the study area. The trend analysis demonstrated an overall increase of 0.3358 mg m−3 in the Chl-a concentration during 1998–2015 (annual increase rate of 0.018 mg m−3 year−1) and four algal blooms and in turn an abnormal increase in Chl-a concentration were occurred in August 2001, September 2005, 2009, and August 2010. The linear model revealed that Chl-a in the northern and middle part of the study area had been influenced by the attenuation coefficient after a one-month lag time. The analysis revealed a sharp decline in Chl-a concentration during 2011–2015 and showed a high correlation with the turbidity and attenuation coefficient in the southern region, while Kd_490nm and remote sensing reflectance did a low one. Generally, Chl-a concentration exhibited a positive correlation with the attenuation coefficient (r = 0.63) and with remote sensing reflectance at the 555 nm (r = 0.111). This study can be used as the basis for predictive modeling to evaluate the changes of water quality and bio-optical indices in the Southern Caspian Sea (SCS).

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