Estimating phytoplankton biomass in coastal waters of Alaska using airborne remote sensing

✍ Scribed by Martín A. Montes-Hugo; Kendall Carder; Robert J. Foy; Jennifer Cannizzaro; Evelyn Brown; Scott Pegau

• Publisher: Elsevier Science
• Year: 2005
• Tongue: English
• Weight: 674 KB
• Volume: 98
• Category: Article
• ISSN: 0034-4257
• DOI: 10.1016/j.rse.2005.08.013

✦ Synopsis

Empirical airborne remote-sensing relationships were examined to estimate chlorophyll a concentration in the first optical depth (chl FOD ) of coastal waters of Afgonak/Kodiak Islands during July -August 2002. Band-ratio and spectral-curvature models were tested using satellite remotesensing reflectance (R rs (k)) measurements. Additional shipboard and airborne R rs (k) data were also analysed to evaluate consistency of proposed chl FOD -R rs (k) relationships. Validation of chlorophyll algorithms was performed using data collected in the northern-part of the Gulf of Alaska and Bering Sea during 1996Sea during , 2002Sea during , and 2003 cruises. Likewise, oceanographic conditions during the surveys were typified to interpret variability of chl FOD fields. The SeaWiFS band-ratio algorithm OC2d was the most sensitive R rs combination (R rs (509)/R rs (553)) to detect chl FOD variability. Conversely, OC2a (R rs (412)/R rs (553)) had the lowest performance to derive chl FOD values. No valid statistical regressions were established for spectral -curvature relationships in the blue spectrum (< 500 nm). Fertile waters (> 5 mg m À 3 ) were preferentially located over shallow banks (¨50 m) and at the entrance of the bays. The approach used in this study to derive chl FOD values could be universal for Alaskan coastal waters. However, chl FOD -R rs (k) relationships must be calibrated locally for a given season.