Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 9 of 9
Full-Text Articles in Life Sciences
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 …
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 …
Cloud And Sun-Glint Statistics Derived From Goes And Modis Observations Over The Intra-Americas Sea For Geo-Cape Mission Planning, Lian Feng, Chuanmin Hu, Brian B. Barnes, Antonio Mannino, Andrew K. Heidinger, Kathleen Strabala, Laura T. Iraci
Cloud And Sun-Glint Statistics Derived From Goes And Modis Observations Over The Intra-Americas Sea For Geo-Cape Mission Planning, Lian Feng, Chuanmin Hu, Brian B. Barnes, Antonio Mannino, Andrew K. Heidinger, Kathleen Strabala, Laura T. Iraci
Marine Science Faculty Publications
Knowledge of cloud cover, frequency, and duration is not only important to study cloud dynamics, but also critical in determining when and where to take ocean measurements from geostationary orbits such as the Geostationary Coastal and Air Pollution Events (GEO-CAPE) mission due to the challenges in achieving complete hemispheric coverage of coastal oceans, estuaries, and inland waters at hourly frequency. Using GOES hourly measurements at 4 km nadir resolution between 2006 and 2011, the number of cloud-free hourly observations per day (Ncf) for solar zenith angle θo < 80° was estimated for each 0.1° location of the Intra-Americas Sea. The number of Sun-glint-affected hourly observations per day (Nsg) was also calculated based on the …
Requirement Of Minimal Signal-To-Noise Ratios Of Ocean Color Sensors And Uncertainties Of Ocean Color Products, Lin Qi, Zhongping Lee, Chuanmin Hu, Menghua Wang
Requirement Of Minimal Signal-To-Noise Ratios Of Ocean Color Sensors And Uncertainties Of Ocean Color Products, Lin Qi, Zhongping Lee, Chuanmin Hu, Menghua Wang
Marine Science Faculty Publications
Using simulations, error propagation theory, and measurements from the Moderate Resolution Imaging Spectroradiometer (MODIS), we determined the minimal signal-to-noise ratio (SNR) required for ocean color measurements and product uncertainties at different spatial and temporal scales. First, based on typical top-of-atmosphere (TOA) radiance over the ocean, we evaluate the uncertainties in satellite-derived Rrs in the visible wavelengths (ΔRrs(vis)) due to sensor noise in both the near-infrared (NIR) and the visible bands. While the former induces noise in Rrs(vis) through atmospheric correction, the latter has a direct impact on Rrs(vis). Such estimated uncertainties are …
Land Adjacency Effects On Modis Aqua Top-Of-Atmosphere Radiance In The Shortwave Infrared: Statistical Assessment And Correction, Lian Feng, Chuanmin Hu
Land Adjacency Effects On Modis Aqua Top-Of-Atmosphere Radiance In The Shortwave Infrared: Statistical Assessment And Correction, Lian Feng, Chuanmin Hu
Marine Science Faculty Publications
Satellite measurements of coastal or inland waters near land/water interfaces suffer from land adjacency effects (LAEs), particularly in the short-wave infrared (SWIR) wavelengths. Here a statistical method was developed to quantify the LAEs as the ratio of top-of-atmosphere (TOA) total radiance (Lt, W m−2 µm−1 sr−1) between near-shore pixels and LAE-free offshore pixels (>12 pixels away from land). The calculations were conducted using MODIS Aqua images between 2003 and 2012 over the Madagascar Island, with results showing the dependency of LAEs on different environmental and observational factors. The LAEs decrease dramatically with increasing …
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 …
Spatiotemporal Chlorophyll-A Dynamics On The Louisiana Continental Shelf Derived From A Dual Satellite Imagery Algorithm, Chengfeng Le, John C. Lehrter, Chuanmin Hu, Michael C. Murrell, Lin Qi
Spatiotemporal Chlorophyll-A Dynamics On The Louisiana Continental Shelf Derived From A Dual Satellite Imagery Algorithm, Chengfeng Le, John C. Lehrter, Chuanmin Hu, Michael C. Murrell, Lin Qi
Marine Science Faculty Publications
A monthly time series of remotely sensed chlorophyll-a (Chlars) over the Louisiana continental shelf (LCS) was developed and examined for its relationship to river discharge, nitrate concentration, total phosphorus concentration, photosynthetically available radiation (PAR), wind speed, and interannual variation in hypoxic area size. A new algorithm for Chlars, tuned separately for clear and turbid waters, was developed using field-observed chlorophyll-a (Chlaobs) collected during 12 cruises from 2002 to 2007. The new algorithm reproduced Chlaobs, with ∼40% and ∼60% uncertainties at satellite pixel level for clear offshore waters and turbid nearshore …
Chlorophyll Aalgorithms For Oligotrophic Oceans: A Novel Approach Based On Three-Band Reflectance Difference, Chuanmin Hu, Zhongping Lee, Bryan Franz
Chlorophyll Aalgorithms For Oligotrophic Oceans: A Novel Approach Based On Three-Band Reflectance Difference, Chuanmin Hu, Zhongping Lee, Bryan Franz
Marine Science Faculty Publications
[1] A new empirical algorithm is proposed to estimate surface chlorophyll a (Chl) concentrations in the global ocean for Chl ≤ 0.25 mg m−3(∼78% of the global ocean area). The algorithm is based on a color index (CI), defined as the difference between remote-sensing reflectance (Rrs, sr−1) in the green and a reference formed linearly between Rrsin the blue and red. For low-Chl waters, in situ data showed a tighter (and therefore better) relationship between CI and Chl than between traditional band ratios and Chl, which was further validated using global …
The Antares Observation Network, Frank E. Muller-Karger, Chuamin Hu, Brock Murch, Charles Taylor
The Antares Observation Network, Frank E. Muller-Karger, Chuamin Hu, Brock Murch, Charles Taylor
Marine Science Faculty Publications
The ANTARES network seeks to understand the variability of the coastal environment on a continental scale and the local, regional, and global factors and processes that modulate this variability. The target are coastal zones of South America and the Caribbean Sea. The initial approach includes developing time series of in situ and satellite-based environmental observations in coastal and oceanic regions. The network is constituted by experts that seek to exchange ideas, develop an infrastructure for mutual logistical and knowledge support, and link in situ time series of observations located around the Americas with real-time and historical satellite-derived time series of …