Abstract
<p> <p id="x-x-sp0005"> <a title="Learn more about Satellite Remote Sensing from ScienceDirect's AI-generated Topic Pages"> Satellite remote sensing </a> has shown the advantage of <a title="Learn more about Water Quality Assessment from ScienceDirect's AI-generated Topic Pages"> water quality assessment </a> at synoptic scales in coastal regions, yet modern sensors such as <a title="Learn more about Sea-Viewing Wide Field-of-View Sensor from ScienceDirect's AI-generated Topic Pages"> SeaWiFS </a> or <a title="Learn more about MODIS from ScienceDirect's AI-generated Topic Pages"> MODIS </a> did not start until the late 1990s. For non-interrupted observations, only the <a title="Learn more about Landsat from ScienceDirect's AI-generated Topic Pages"> Landsat </a> series have the potential to detect major water quality events since the 1980s. However, such ability is hindered by the unknown data quality or consistency through time. Here, using the Florida Keys as a case study, we demonstrate an approach to identify historical water quality events through improved atmospheric correction of Landsat data and cross-validation with concurrent MODIS data. After aggregation of the <a title="Learn more about Landsat 5 from ScienceDirect's AI-generated Topic Pages"> Landsat-5 </a> Thematic Mapper (TM) 30-m pixels to 240-m pixels (to increase the signal-to-noise ratio), a MODIS-like atmospheric correction approach using the Landsat shortwave-infrared (SWIR) bands was developed and applied to the entire Landsat-5 TM data series between 1985 and 2010. <a title="Learn more about Remote Sensing from ScienceDirect's AI-generated Topic Pages"> Remote sensing </a> reflectance (R <sub> RS </sub> ) anomalies from Landsat (2 standard deviations from a pixel-specific monthly climatology) were found to detect MODIS R <sub> RS </sub> anomalies with over 90% accuracy for all three bands for the same period of 2002–2010. Extending this analysis for the entire Landsat-5 time-series revealed R <sub> RS </sub> anomaly events in the 1980s and 1990s, some of which are corroborated by known ecosystem changes due in part to changes in local freshwater flow. Indeed, TM R <sub> RS </sub> anomalies were shown to be useful in detecting shifts in <a title="Learn more about Sea Grasses from ScienceDirect's AI-generated Topic Pages"> seagrass </a> density, turbidity increases, black water events, and <a title="Learn more about Phytoplankton from ScienceDirect's AI-generated Topic Pages"> phytoplankton </a> blooms. These findings have large implications for ongoing and future water quality assessment in the Florida Keys as well as in many other coastal regions. </p></p>
Original language | American English |
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Journal | Remote Sensing of Environment |
Volume | 140 |
DOIs | |
State | Published - Jan 1 2014 |
Keywords
- Water quality
- Remote sensing
- Atmospheric correction
- Seagrass
Disciplines
- Life Sciences