Estimation of chlorophyll-a concentration in turbid productive waters using airborne hyperspectral data.
Algorithms based on red and near infra-red (NIR) reflectances measured using field spectrometers have been previously shown to yield accurate estimates of chlorophyll-a concentration in turbid productive waters, irrespective of variations in the bio-optical characteristics of water. The objective of this study was to investigate the performance of NIR-red models when applied to multi-temporal airborne reflectance data acquired by the hyperspectral sensor, Airborne Imaging Spectrometer for Applications (AISA), with non-uniform atmospheric effects across the dates of data acquisition. The results demonstrated the capability of the NIR-red models to capture the spatial distribution of chlorophyll-a in surface waters without the need for atmospheric correction. However, the variable atmospheric effects did affect the accuracy of chlorophyll-a retrieval. Two atmospheric correction procedures, namely, Fast Line-of-sight Atmospheric Adjustment of Spectral Hypercubes (FLAASH) and QUick Atmospheric Correction (QUAC), were applied to AISA data and their results were compared. QUAC produced a robust atmospheric correction, which led to NIR-red algorithms that were able to accurately estimate chlorophyll-a concentration, with a root mean square error of 5.54 mg m(-3) for chlorophyll-a concentrations in the range 2.27-81.17 mg m(-3).
Center for Advanced Land Management Information Technologies (CALMIT), University of Nebraska-Lincoln, 303 Hardin Hall, Lincoln, USA; School of Natural Resources, University of Nebraska-Lincoln, Lincoln, NE, USA. wesley.moses.ctr.in@nrl.navy.mil
Wesley J
WJ
Moses
Anatoly A
AA
Gitelson
Richard L
RL
Perk
Daniela
D
Gurlin
Donald C
DC
Rundquist
Bryan C
BC
Leavitt
Tadd M
TM
Barrow
Paul
P
Brakhage
D001272:Atmosphere / Q000737:chemistry*; D002734:Chlorophyll / Q000032:analysis*; D000077194:Chlorophyll A; D060106:Lakes / Q000737:chemistry*; D016014:Linear Models; D008956:Models, Chemical; D009329:Nebraska; D009391:Nephelometry and Turbidimetry / Q000379:methods*; D019265:Spectroscopy, Near-Infrared / Q000379:methods*; D013997:Time Factors; D060753:Water Quality
D002734:Chlorophyll; D000077194:Chlorophyll A