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Full-Text Articles in Life Sciences
Mississippi River And Campeche Bank (Gulf Of Mexico) Episodes Of Cross-Shelf Export Of Coastal Waters Observed With Satellites, Daniel Otis, Matthieu Le Hénaff, Vassiliki H. Kourafalou, Lucas Mceachron, Frank Muller-Karger
Mississippi River And Campeche Bank (Gulf Of Mexico) Episodes Of Cross-Shelf Export Of Coastal Waters Observed With Satellites, Daniel Otis, Matthieu Le Hénaff, Vassiliki H. Kourafalou, Lucas Mceachron, Frank Muller-Karger
Marine Science Faculty Publications
The cross-shelf advection of coastal waters into the deep Gulf of Mexico is important for the transport of nutrients or potential pollutants. Twenty years of ocean color satellite imagery document such cross-shelf transport events via three export pathways in the Gulf of Mexico: from the Campeche Bank toward the central Gulf, from the Campeche Bank toward the Florida Straits, and from the Mississippi Delta to the Florida Straits. A catalog of these events was created based on the visual examination of 7280 daily satellite images. Water transport from the Campeche Bank to the central Gulf occurred frequently and with no …
Can Modis Land Reflectance Products Be Used For Estuarine And Inland Waters?, Lian Feng, Chuanmin Hu, Junsheng Li
Can Modis Land Reflectance Products Be Used For Estuarine And Inland Waters?, Lian Feng, Chuanmin Hu, Junsheng Li
Marine Science Faculty Publications
Although designed for land surfaces, MODIS Aqua surface reflectance data products (MYD09, termed as R_Land in this work) have also been used for water applications. Yet to date their uncertainties and general suitability in such applications have rarely been documented. In this study, R_Land products of two regions (Chesapeake Bay and Taihu Lake) between July 2002 and December 2015 are evaluated against in situ measurements and against reflectance products derived by the MODIS Ocean Team using atmospheric correction schemes specifically designed for water applications, namely the default atmospheric correction method based on the near-infrared (NIR) bands (denoted as R_NIR, data …
Remote Estimation Of Biomass Of Ulva Prolifera Macroalgae In The Yellow Sea, Lianbo Hu, Chuanmin Hu, He Ming-Xia
Remote Estimation Of Biomass Of Ulva Prolifera Macroalgae In The Yellow Sea, Lianbo Hu, Chuanmin Hu, He Ming-Xia
Marine Science Faculty Publications
Since 2008, macroalgal blooms of Ulva prolifera (also called green tides) occurred every summer in the Yellow Sea (YS), causing environmental and economic problems. A number of studies have used satellite observations to estimate the severity of the blooms through estimating the bloom size and duration. However, a critical bloom parameter, namely biomass, has never been objectively determined due to lack of measurements. In this study, laboratory experiments were conducted to measure U. prolifera biomass (wet weight) per unit area and the corresponding spectral reflectance, through which a robust relationship has been established to link biomass per area to …
Satellite Observation Of Particulate Organic Carbon Dynamics On The Louisiana Continental Shelf, Chengfeng Le, John C. Lehrter, Chuanmin Hu, Hugh Macintyre, Marcus W. Beck
Satellite Observation Of Particulate Organic Carbon Dynamics On The Louisiana Continental Shelf, Chengfeng Le, John C. Lehrter, Chuanmin Hu, Hugh Macintyre, Marcus W. Beck
Marine Science Faculty Publications
Particulate organic carbon (POC) plays an important role in coastal carbon cycling and the formation of hypoxia. Yet, coastal POC dynamics are often poorly understood due to a lack of long-term POC observations and the complexity of coastal hydrodynamic and biogeochemical processes that influence POC sources and sinks. Using field observations and satellite ocean color products, we developed a new multiple regression algorithm to estimate POC on the Louisiana Continental Shelf (LCS) from satellite observations. The algorithm had reliable performance with mean relative error (MRE) of ∼40% and root mean square error (RMSE) of ∼50% for MODIS and SeaWiFS images …
Predicting Sargassum Blooms In The Caribbean Sea From Modis Observations, Mengqiu Wang, Chuanmin Hu
Predicting Sargassum Blooms In The Caribbean Sea From Modis Observations, Mengqiu Wang, Chuanmin Hu
Marine Science Faculty Publications
Recurrent and significant Sargassum beaching events in the Caribbean Sea (CS) have caused serious environmental and economic problems, calling for a long-term prediction capacity of Sargassum blooms. Here we present predictions based on a hindcast of 2000–2016 observations from Moderate Resolution Imaging Spectroradiometer (MODIS), which showed Sargassum abundance in the CS and the Central West Atlantic (CWA), as well as connectivity between the two regions with time lags. This information was used to derive bloom and nonbloom probability matrices for each 1° square in the CS for the months of May–August, predicted from bloom conditions in a hotspot region in …
Refinement Of The Critical Angle Calculation For The Contrast Reversal Of Oil Slicks Under Sunglint, Yingcheng Lu, Shaojie Sun, Minwei Zhang, Brock Murch, Chuanmin Hu
Refinement Of The Critical Angle Calculation For The Contrast Reversal Of Oil Slicks Under Sunglint, Yingcheng Lu, Shaojie Sun, Minwei Zhang, Brock Murch, Chuanmin Hu
C-IMAGE Publications
It has long been observed that oil slicks under sunglint can reverse their optical contrast against nearby oil‐free seawater. Such a phenomenon has been described through both empirical statistical analysis of the sunglint strength and modeled theoretically using a critical angle concept. The critical angle, in this model, is the angle at which the image pixels show no or negligible contrast between oiled and nonoiled seawater. Pixels away from this critical angle show either positive or negative contrast from the oil‐free pixels. Although this concept has been fully demonstrated in the published literature, its calculation needs to be further refined …
Sun Glint Requirement For The Remote Detection Of Surface Oil Films, Shaojie Sun, Chuanmin Hu
Sun Glint Requirement For The Remote Detection Of Surface Oil Films, Shaojie Sun, Chuanmin Hu
C-IMAGE Publications
Natural oil slicks in the western Gulf of Mexico are used to determine the sun glint threshold required for optical remote sensing of oil films. The threshold is determined using the same‐day image pairs collected by Moderate Resolution Imaging Spectroradiometer (MODIS) Terra (MODIST), MODIS Aqua (MODISA), and Visible Infrared Imaging Radiometer Suite (VIIRS) (N = 2297 images) over the same oil slick locations where at least one of the sensors captures the oil slicks. For each sensor, statistics of sun glint strengths, represented by the normalized glint reflectance (L GN, sr−1), when oil slicks can and cannot be …
Modified Modis Fluorescence Line Height Data Product To Improve Image Interpretation For Red Tide Monitoring In The Eastern Gulf Of Mexico, Chuanmin Hu, Lian Feng
Modified Modis Fluorescence Line Height Data Product To Improve Image Interpretation For Red Tide Monitoring In The Eastern Gulf Of Mexico, Chuanmin Hu, Lian Feng
Marine Science Faculty Publications
Several satellite-based methods have been used to detect and trace Karenia brevis red tide blooms in the eastern Gulf of Mexico. Some require data statistics and multiple data products while others use a single data product. Of these, the MODIS normalized fluorescence line height (nFLH) has shown its advantage of detecting blooms in waters rich in colored dissolved organic matter, thus having been used routinely to assess bloom conditions by the Florida Fish and Wildlife Conservation Commission (FWC), the official state agency of Florida responsible for red tide monitoring and mitigation. However, elevated sediment concentrations in the water column due …
World’S Largest Macroalgal Blooms Altered Phytoplankton Biomass In Summer In The Yellow Sea: Satellite Observations, Qianguo Xing, Chuanmin Hu, Danling Tang, Liqiao Tian, Shilin Tang, Xiao Hua Wang, Mingjing Lou, Xuelu Gao
World’S Largest Macroalgal Blooms Altered Phytoplankton Biomass In Summer In The Yellow Sea: Satellite Observations, Qianguo Xing, Chuanmin Hu, Danling Tang, Liqiao Tian, Shilin Tang, Xiao Hua Wang, Mingjing Lou, Xuelu Gao
Marine Science Faculty Publications
Since 2008, the world’s largest blooms of the green macroalgae, Ulva prolifera, have occurred every summer in the Yellow Sea, posing the question of whether these macroalgal blooms (MABs) have changed the phytoplankton biomass due to their perturbations of nutrient dynamics. We have attempted to address this question using long-term Moderate Resolution Imaging Spectroradiometer (MODIS) observations. A new MODIS monthly time-series of chlorophyll-a concentrations (Chl-a, an index of phytoplankton biomass) was generated after removing the macroalgae-contaminated pixels that were characterized by unexpectedly high values in the daily Chl-a products. Compared with Chl-a during July of 2002–2006 (the pre-MAB period), Chl-a …
Changes In Vegetative Coverage Of The Hongze Lake National Wetland Nature Reserve: A Decade-Long Assessment Using Modis Medium-Resolution Data, Kun Yu, Chuanmin Hu
Changes In Vegetative Coverage Of The Hongze Lake National Wetland Nature Reserve: A Decade-Long Assessment Using Modis Medium-Resolution Data, Kun Yu, Chuanmin Hu
Marine Science Faculty Publications
Wetlands are important ecosystems on Earth. However, global wetland coverage is being reduced due to both anthropogenic and natural effects. Thus, assessment of temporal changes in vegetative coverage, as a measure of the wetland health, is critical to help implement effective management plans and provide inputs for climate-related research. In this work, 596 moderate-resolution imaging spectroradiometer (MODIS) 250-m resolution images of the Hongze Lake national wetland nature reserve from 2000 to 2009 were used to study the vegetative coverage (above the water surface) of the reserve. Three vegetation indices [normalized difference vegetation index (NDVI), enhanced VI (EVI), and floating algae …
Satellite-Observed Black Water Events Off Southwest Florida: Implications For Coral Reef Health In The Florida Keys National Marine Sanctuary, Jun Zhao, Chuanmin Hu, Brian Lapointe, Nelson Melo, Elizabeth M. Johns, Ryan H. Smith
Satellite-Observed Black Water Events Off Southwest Florida: Implications For Coral Reef Health In The Florida Keys National Marine Sanctuary, Jun Zhao, Chuanmin Hu, Brian Lapointe, Nelson Melo, Elizabeth M. Johns, Ryan H. Smith
Marine Science Faculty Publications
A “black water” event, as observed from satellites, occurred off southwest Florida in 2012. Satellite observations suggested that the event started in early January and ended in mid-April 2012. The black water patch formed off central west Florida and advected southward towards Florida Bay and the Florida Keys with the shelf circulation, which was confirmed by satellite-tracked surface drifter trajectories. Compared with a previous black water event in 2002, the 2012 event was weaker in terms of spatial and temporal coverage. An in situ survey indicated that the 2012 black water patch contained toxic K. brevis and had relatively low …
Long-Term Statistical Assessment Of Aqua-Modis Aerosol Optical Depth Over Coastal Regions: Bias Characteristics And Uncertainty Sources, Jacob C. Anderson, Jun Wang, Jing Zeng, Gregory Leptoukh, Maksym Petrenko, Charles Ichoku, Chuanmin Hu
Long-Term Statistical Assessment Of Aqua-Modis Aerosol Optical Depth Over Coastal Regions: Bias Characteristics And Uncertainty Sources, Jacob C. Anderson, Jun Wang, Jing Zeng, Gregory Leptoukh, Maksym Petrenko, Charles Ichoku, Chuanmin Hu
Marine Science Faculty Publications
Coastal regions around the globe represent a major source for anthropogenic aerosols in the atmosphere, but the surface characteristics may not be optimal for the Moderate Resolution Imaging Spectroradiometer (MODIS) algorithms designed for aerosol retrievals over dark land or ocean surfaces. Using data collected from 62 coastal stations worldwide by the Aerosol Robotic Network (AERONET) in 2002–2011, statistical assessments of uncertainties are conducted for coastal aerosol optical depth (AOD) retrieved from MODIS measurements aboard the Aqua satellite (i.e., the Collection 5.1 MYD04 data product generated by the MODIS atmosphere group). It is found that coastal AODs (at 550 nm) characterised …
Satellite-Based Virtual Buoy System To Monitor Coastal Water Quality, Chuanmin Hu, Brian B. Barnes, Brock Murch, Paul R. Carlson
Satellite-Based Virtual Buoy System To Monitor Coastal Water Quality, Chuanmin Hu, Brian B. Barnes, Brock Murch, Paul R. Carlson
Marine Science Faculty Publications
There is a pressing need to assess coastal and estuarine water quality state and anomaly events to facilitate coastal management, but such a need is hindered by lack of resources to conduct frequent ship-based or buoy-based measurements. Here, we established a virtual buoy system (VBS) to facilitate satellite data visualization and interpretation of water quality assessment. The VBS is based on a virtual antenna system (VAS) that obtains low-level satellite data and generates higher-level data products using both National Aeronautics and Space Administration standard algorithms and regionally customized algorithms in near real time. The VB stations are predefined and carefully …
Human Induced Turbidity Changes In Poyang Lake Between 2000 And 2010: Observations From Modis, Lian Feng, Chuanmin Hu, Xiaoling Chen, Liqiao Tian, Liqiong Chen
Human Induced Turbidity Changes In Poyang Lake Between 2000 And 2010: Observations From Modis, Lian Feng, Chuanmin Hu, Xiaoling Chen, Liqiao Tian, Liqiong Chen
Marine Science Faculty Publications
A robust retrieval algorithm to estimate concentrations of total suspended sediments (TSS) in Poyang Lake (the largest freshwater lake in China) was developed using Moderate Resolution Imaging Spectroradiometer (MODIS) medium-resolution (250 m) data from 2000 to 2010 and in situ data collected during two cruise surveys. The algorithm was based on atmospherically corrected surface reflectance at 645 nm, with 1240 nm data serving as a reference for aerosols and a nearest-neighbor method was used to avoid land adjacency effect. The algorithm showed an uncertainty of 30–40% for TSS ranging between 3 and 200 mg L−1. Long-term TSS distribution …
Moderate Resolution Imaging Spectroradiometer (Modis) Observations Of Cyanobacteria Blooms In Taihu Lake, China, Chuanmin Hu, Zhongping Lee, Ronghua Ma, Kun Yu, Daqiu Li, Shaoling Shang
Moderate Resolution Imaging Spectroradiometer (Modis) Observations Of Cyanobacteria Blooms In Taihu Lake, China, Chuanmin Hu, Zhongping Lee, Ronghua Ma, Kun Yu, Daqiu Li, Shaoling Shang
Marine Science Faculty Publications
A novel approach was used with data from the Moderate Resolution Imaging Spectroradiometer (MODIS) to characterize the intense blooms of cyanobacteria (primarily Microcystis aeruginosa) in Taihu Lake, China's third largest freshwater lake. The approach involves first deriving a floating algae index (FAI) based on the medium‐resolution (250 and 500 m) MODIS reflectance data at 645, 859, and 1240 nm after correction of the ozone/gaseous absorption and Rayleigh scattering effects and then objectively determining the FAI threshold value (−0.004) to separate the bloom and nonbloom waters. By definition, the term “bloom” or “floating algae” refers to bloom where cyanobacteria form …