Diurnal variability of turbidity and light attenuation in the southern North Sea from the geostationary SEVIRI sensor

Transcription

1 Publication in review in Remote Sensing of the Environment Diurnal variability of turbidity and light attenuation in the southern North Sea from the geostationary SEVIRI sensor Griet Neukermans 1,2 Kevin Ruddick 1 Quinten Vanhellemont 1 Naomi Greenwood 3 1 Management Unit of the North Sea Mathematical Models (MUMM), Belgium 2 Université du Littoral Côte d Opale, Laboratoire d'océanologie et Géosciences (LOG), France 3 Center for Environment, Fisheries and Aquaculture Science (CEFAS), UK

2 spectral response w(l), atmospheric transmittance Neukermans et al. (2009). Mapping SPM from geostationary satellites... Optics Express 1.0 SEVIRI full disk Every 15 minutes 3 x 3 km² 1 x 1 km² 3 x 6 km² 1 x 2 km² Viewing zenith angle ( ) R NIR HRV l (mm) wavelength (mm) w H20 OZONE MOL-SCAT HRV VIS0.6 VIS0.8 NIR1.6 Study area

3 SEVIRI optimal w retrieval e = 0.84 e = 1.02 e = 1.32? w 0.08 Optimal range w s t (0.6) c a(0.8) 0, v e (0.8) c ( s e ) Digitization w, m Turbid water (assumption of constant s ) Neukermans G. (2012). Ph.D. dissertation.

4 Neukermans G. (2012). Ph.D. dissertation. SEVIRI vs. MODIS marine reflectance SEVIRI w SEVIRI w MODIS MODIS 0 ( M 645) w 0 ( M 645) w 6 May 2008, 13h UTC 8 March 2009, 13h UTC

5 in situ T and K PAR data: SmartBuoys D WG T TH1 Mills et al. (2003) PAR 0 +, 1, 2 m K PAR T (FNU) on 11 February 2008, 12:00 h UTC PAR(1m ) log PAR(2m) in situ T and K PAR every 30 minutes

6 Retrieval algorithms for T and K PAR Turbidity (T) and [SPM] algorithm (Nechad et al. 2009, 2010): T A C w w Attenuation of PAR (K PAR ) algorithm (Devlin et al. 2008): K PAR [SPM] 2 year dataset ( ) of SEVIRI T and K PAR every 15 minutes

7 K PAR (m -1 ) SEVIRI vs. in situ T and K PAR atmospheric correction, retrieval algorithms, spatial resolution, in situ measurement uncertainty 1:1 line fit 1:1 line fit K PAR (m -1 ) log 10 regression PE (%) percentiles 80% of SEVIRI T is within 53% of in situ T n r slope offset RMSE and T % K PAR of SEVIRI 1492 K0.93 PAR is 0.85within % 0.34of 2in 18 situ 81 K PAR

8 Diurnal variability of T

9 Diurnal variability of T

10 SEVIRI daily composite of 34 images Quasi cloudfree MODIS: 1 image 60% clouded remotely sensed ( ) vs. in-situ (, ) diurnal variability of turbidity t(t max ) SB T max t( )

11 SEVIRI daily composite of 34 images Quasi cloudfree MODIS: 1 image 60% clouded SEVIRI ( ) vs. in-situ (, ) diurnal variability of T t(t max ) SB t(t max )

12 t(t max ) h UTC Comparison of T time series 1:1 line +/- 1 h lines Diurnal variability of T is picked up well by SEVIRI with phase difference generally <1h SB t(t max ) h UTC

13 K PAR (m -1 ) K PAR (m -1 ) t(k PARmax ) h UTC K PAR (m -1 ) and K PAR time series SEVIRI SmartBuoy SB t(k PARmax ) h UTC also picked up well by SEVIRI

14 Conclusions SEVIRI w MODIS w SEVIRI MODIS Good correspondence between SEVIRI and MODIS marine reflectance Large uncertainties in clear water (digitization) and in very turbid waters (atmospheric correction) On cloudfree days: SEVIRI detects tidal variability of T and K d in turbid SNS waters Available for the first time from space Applications in ecosystem models, sediment transport modeling, monitoring of T Days with moving clouds: significant increase in data availability, compared to polar-orbiters Extension of atmospheric correction methodology to full SEVIRI disk or other meteorological sensors

15 Where else can this work? GOCI COMS SEVIRI MSG MSU Electro

16 Publications Neukermans G., Optical in situ and geostationary satellite-borne observations of suspended particles in coastal waters. Ph. D. dissertation of the Université du Littoral Côte d Opale, pp. 210, Academic & Scientific publishers, Brussels, Belgium. ISBN Neukermans G., K. Ruddick and N. Greenwood. Diurnal variability of turbidity and light attenuation in the southern North Sea from the SEVIRI geostationary sensor. (in review in Remote sensing of the Environment). Nechad B., Ruddick, K.G. and G. Neukermans, Calibration and validation of a generic multisensor algorithm for mapping of turbidity in coastal waters. Proceedings of SPIE "Remote Sensing of the Ocean, Sea Ice, and Large Water Regions" Conference held in Berlin (Germany), 31 August Proc. SPIE Vol. 7473, 74730H. Neukermans G., K. Ruddick, E. Bernard, D. Ramon, B. Nechad and P.Y. Deschamps, Mapping Total Suspended Matter from geostationary satellites: a feasibility study with SEVIRI in the Southern North Sea. Optics Express, 17(16):