Satellite derived euphotic depth in the Southern Ocean: Implications for primary production modelling

REMOTE SENSING OF ENVIRONMENT

卷:137

Article

Soppa, M. A.¹  Dinter, T.^1,2  Taylor, B. B.¹  Bracher, A.^1,2 

[1] Helmholtz Zentrum Polar & Meeresforsch, Alfred Wegener Inst, D-27570 Bremerhaven, Germany

[2] Univ Bremen, Inst Environm Phys, D-28334 Bremen, Germany

关键词: Euphotic zone;    SeaWiFS;    MODIS;    Southern Ocean;    Phytoplankton absorption;    Ocean colour;   

DOI  :  10.1016/j.rse.2013.06.017

来源: Elsevier

【 摘 要 】

The euphotic depth (Z(eu)) is a key parameter in modelling primary production (PP) using satellite ocean colour. However, evaluations of satellite Z(eu) products are scarce. The objective of this paper is to investigate existing approaches and sensors to estimate Z(eu) from satellite and to evaluate how different Z(eu) products might affect the estimation of PP in the Southern Ocean (SO). Euphotic depth was derived from MODIS and SeaWiFS products of (i) surface chlorophyll-a (Z(eu)-Chla) and (ii) inherent optical properties (Z(eu)-IOP). They were compared with in situ measurements of Z(eu) from different regions of the SO. Both approaches and sensors are robust to retrieve Z(eu), although the best results were obtained using the IOP approach and SeaWiFS data, with an average percentage of error (E) of 25.43% and mean absolute error (MAE) of 0.10 m (log scale). Nevertheless, differences in the spatial distribution of Z(eu)-Chla and Z(eu)-IOP for both sensors were found as large as 30% over specific regions. These differences were also observed in PP. On average, PP based on Z(eu)-Chla was 8% higher than PP based on Z(eu)-IOP, but it was up to 30% higher south of 60 degrees S. Satellite phytoplankton absorption coefficients (a(ph)) derived by the Quasi-Analytical Algorithm at different wavelengths were also validated and the results showed that MODIS a(ph) are generally more robust than SeaWiFS. Thus, MODIS a(ph) should be preferred in PP models based on a(ph) in the SO. Further, we reinforce the importance of investigating the spatial differences between satellite products, which might not be detected by the validation with in situ measurements due to the insufficient amount and uneven distribution of the data. (c) 2013 Elsevier Inc. All rights reserved.

【 授权许可】

Free