A5042345986- Marine and coastal ecosystems
- Water Quality Monitoring and Analysis
- Coral and Marine Ecosystems Studies
- Atmospheric Ozone and Climate
- Atmospheric aerosols and clouds
- Atmospheric and Environmental Gas Dynamics
- Marine Biology and Ecology Research
- Calibration and Measurement Techniques
- Water Quality Monitoring Technologies
- Atmospheric chemistry and aerosols
- Aquatic Ecosystems and Phytoplankton Dynamics
- Oceanographic and Atmospheric Processes
- Remote Sensing in Agriculture
- Remote-Sensing Image Classification
- Isotope Analysis in Ecology
- Marine and coastal plant biology
- Water Quality and Pollution Assessment
- Remote Sensing and Land Use
- Infrared Target Detection Methodologies
- Marine and fisheries research
- Microbial Community Ecology and Physiology
- Environmental Monitoring and Data Management
- Advanced Image Fusion Techniques
- Geological Modeling and Analysis
- Spacecraft Design and Technology
Goddard Space Flight Center
2016-2025
University of Maine
2014
National Aeronautics and Space Administration
2014
Science Systems and Applications (United States)
2003-2013
University of Connecticut
2003
The atmospheric correction algorithm employed by the NASA Ocean Biology Processing Group requires an assumption of negligible water-leaving reflectance in near-infrared region spectrum. For waters where this is not valid, optical model used to estimate reflectance. We describe as implemented for sixth reprocessing SeaWiFS mission-long time-series (September 2009). Application resulted significant reductions number negative retrievals turbid and optically complex waters, improved agreement...
Ocean color measured from satellites provides daily, global estimates of marine inherent optical properties (IOPs). Semi-analytical algorithms (SAAs) provide one mechanism for inverting the water observed by satellite into IOPs. While numerous SAAs exist, most are similarly constructed and few appropriately parameterized all masses seasons. To initiate community-wide discussion these limitations, NASA organized two workshops that deconstructed to identify similarities uniqueness progress...
A high degree of consistency and comparability among chlorophyll algorithms is necessary to meet the goals merging data from concurrent overlapping ocean color missions for increased coverage global extend existing time series encompass recently launched those planned near future, such as PACE, OLCI, HawkEye, EnMAP SABIA-MAR. To accomplish these goals, we developed 65 empirical (OC) maximum band ratio (MBR) 25 satellite instruments using largest available most globally representative...
Abstract The Plankton, Aerosol, Cloud, Ocean Ecosystem (PACE) mission represents the National Aeronautics and Space Administration’s (NASA) next investment in satellite ocean color study of Earth’s ocean–atmosphere system, enabling new insights into oceanographic atmospheric responses to changing climate. PACE objectives include extending systematic cloud, aerosol, biological biogeochemical data records, making essential measurements further understand marine carbon cycles, food-web...
Performance assessment of ocean color satellite data has generally relied on statistical metrics chosen for their common usage and the rationale selecting certain is infrequently explained.Commonly reported statistics based mean squared errors, such as coefficient determination (r 2 ), root square error, regression slopes, are most appropriate Gaussian distributions without outliers and, therefore, often not ideal algorithm performance assessment, which limited by sample availability.In...
The retrieval of ocean color radiometry from space-based sensors requires on-orbit vicarious calibration to achieve the level accuracy desired for quantitative oceanographic applications. approach developed by NASA Ocean Biology Processing Group (OBPG) adjusts integrated instrument and atmospheric correction system retrieve normalized water-leaving radiances that are in agreement with ground truth measurements. method is independent satellite sensor or source data, but it specific algorithm....
Ocean color measured from satellites provides daily global, synoptic views of spectral waterleaving reflectances that can be used to generate estimates marine inherent optical properties (IOPs). These reflectances, namely the ratio upwelled radiances downwelled irradiances, describe light exiting a water mass defines its color. IOPs are absorption and scattering characteristics ocean dissolved particulate constituents. Because their dependence on concentration composition constituents,...
Photosynthetic production of organic matter by microscopic oceanic phytoplankton fuels ocean ecosystems and contributes roughly half the Earth's net primary production. For 13 years, Sea-viewing Wide Field-of-view Sensor (SeaWiFS) mission provided first consistent, synoptic observations global ecosystems. Changes in surface chlorophyll concentration, biological property retrieved from SeaWiFS, have traditionally been used as a metric for abundance its distribution largely reflects patterns...
Ocean color satellites have provided a synoptic view of global phytoplankton for over 25 years through near surface measurements the concentration chlorophyll a. While remote sensing ocean has revolutionized our understanding and their role in oceanic freshwater ecosystems, it is important to consider both total biomass changes community composition order fully understand dynamics aquatic ecosystems. With upcoming launch NASA's Plankton, Aerosol, Clouds, Ecosystem (PACE) mission, we will be...
Following the theory of error propagation, we developed analytical functions to illustrate and evaluate uncertainties inherent optical properties (IOPs) derived by quasi-analytical algorithm (QAA). In particular, evaluated effects these parameters on inverted IOPs: absorption coefficient at reference wavelength, extrapolation particle backscattering coefficient, spectral ratios coefficients phytoplankton detritus/gelbstoff, respectively. With a systematically simulated data set (46,200...
Cyanobacterial harmful algal blooms (cyanoHAB) cause extensive problems in lakes worldwide, including human and ecological health risks, anoxia fish kills, taste odor problems. CyanoHABs are a particular concern both recreational waters drinking source because of their dense biomass the risk exposure to toxins. Successful cyanoHAB assessment using satellites may provide an indicator for protection, In this study, methods were developed assess utility satellite technology detecting frequency...
The Operational Land Imager (OLI) is a multispectral radiometer hosted on the recently launched Landsat8 satellite. OLI includes suite of relatively narrow spectral bands at 30 m spatial resolution in visible to shortwave infrared, which makes it potential tool for ocean color radiometry: measurement reflected radiance upwelling from beneath surface that carries information biogeochemical constituents upper euphotic zone. To evaluate measure color, processing support was implemented...
Regional differences in the Sea‐viewing Wide Field‐of‐view Sensor chlorophyll algorithm uncertainty were observed a large global data set containing coincident situ measurements of concentration ( Chla ) and spectral radiometry. The was found to be systematic when sorted by ocean: Atlantic, Pacific, Southern, Indian Oceans. Artifacts associated with different instrumentation analytical methods had been previously ruled out. Given these oceanic biases algorithm, we hypothesized that oceans...
Abstract A recently developed algorithm to estimate surface ocean chlorophyll a concentrations (Chl in mg m −3 ), namely, the color index (OCI) algorithm, has been adopted by U.S. National Aeronautics and Space Administration apply all satellite sensors produce global Chl maps. The is hybrid between band‐difference for low‐Chl waters traditional band‐ratio algorithms (OCx) higher‐Chl waters. In this study, OCI revisited its coefficients transition OCx using merged data set of...
Abstract Cyanobacterial harmful algal blooms (cyanoHABs) are a serious environmental, water quality and public health issue worldwide because of their ability to form dense biomass produce toxins. Models algorithms have been developed detect quantify cyanoHABs using remotely sensed data but not for quantifying bloom magnitude, information that would guide management decisions. We propose method seasonal annual cyanoHAB magnitude in lakes reservoirs. The is the spatiotemporal mean weekly or...
Passive ocean color images have provided a sustained synoptic view of the distribution optical properties and biogeochemical parameters for past twenty-plus years. These revolutionized our ocean. Remote sensing has relied on measurements radiance emerging at top atmosphere, thus neglecting polarization vertical components. Ocean remote utilizes intensity spectral variation visible light scattered upward from beneath surface to derive concentrations constituents inherent within layer. However...
Cyanobacterial harmful algal blooms (CyanoHAB) are thought to be increasing globally over the past few decades, but relatively little quantitative information is available about spatial extent of blooms. Satellite remote sensing provides a potential technology for identifying cyanoHABs in multiple water bodies and across geo-political boundaries. An assessment method was developed using MEdium Resolution Imaging Spectrometer (MERIS) imagery quantify cyanoHAB surface area extent, transferable...
Ocean color remote sensing is an important tool to monitor water quality and biogeochemical conditions of ocean.Atmospheric correction, which obtains water-leaving radiance from the total measured by satellite-borne or airborne sensors, remains a challenging task for coastal waters due complex optical properties aerosols ocean waters.In this paper, we report research algorithm on aerosol retrieval with emphasis waters, uses coupled atmosphere radiative transfer model fit polarized...
Lakes and other surface fresh waterbodies provide drinking water, recreational economic opportunities, food, critical support for humans, aquatic life, ecosystem health. are also productive ecosystems that habitats influence global cycles. Chlorophyll concentration provides a common metric of water quality, is frequently used as proxy lake trophic state. Here, we document the generation distribution complete MEdium Resolution Imaging Spectrometer (MERIS; Appendix A list abbreviations)...
Cyanobacterial blooms can have negative effects on human health and local ecosystems. Field monitoring of cyanobacterial be costly, but satellite remote sensing has shown utility for more efficient spatial temporal across the United States. Here, imagery was used to assess annual frequency surface blooms, defined each pixel as percentage images that throughout year exhibiting detectable cyanobacteria. assessed 2,196 large lakes in 46 states continental States (CONUS) using from European...
The Ocean Color Instrument (OCI) is the primary payload on NASA's Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission. Its purpose to enable new scientific studies of biology, aerosols, and clouds. This paper describes design instrument its radiometric performance as measured during prelaunch characterization campaign. OCI will be first radiometer provide hyperspectral (340nm-895nm) daily global coverage top-of-atmosphere radiances. Seven multispectral bands cover wavelengths from 940nm...