PROBA scenes acquired over our study sites (dates in red fully accomplish the request characteristics) From 12 requests only 6 images have been acquired from which only 2 fully comply with the suitable spectral and spatial characteristics. Nominal nadir acquisitions are shifted in average 3.4 km from the proposed centre coordinates. Average delivery time of Proba images is about 26 days.

PROBA scenes acquired over Doñana sites (Red squares are for Doñana North and yellow for the South) Yellow dots indicate the requested centre coordinates of the scenes for both sites 10 km Landsat TM RGB (5-4-3)

Example of stripe removal with the help of HDFClean This tool not only helps in eliminating stripping effect and missing pixels but also in rotating to a proper N-S axe the different angles of Proba images

Distribution of bands for the 2 different Proba Configuration Modes acquired over Doñana Although several bands in the Land/Aerosol configuration allow water discrimination, there is a lack of information in the 570-630 nm region covered in the mode Water by 2 bands (8 & 9) that may help in detecting Azolla ssp. However, mode 3 images are being explored in order to evaluate the reliability of the atmospheric correction which is a priori only suitable for water bodies and to check general usability for our main purposes.

0º mode 2 images acquired by Proba over Doñana North (24/12/2006) and location of the “deep water” pixel Zoom Window The “water” pixel was chosen according to the deepest location in the marsh inside the Proba scene (1.5 m). Radiances show the high absorption in the IR bands confirming the suitability of the point Proba RGB composition uses 17-15-9 bands Full scene Zoom in

Spectral signature of the “deep water” pixel: Evaluating Atmospheric correction (Guanter et al. 2005) Although radiometric validation is not always affordable, reflectance signature for the deep water pixel seem to behave as expected. The 600 and 700 reflectance peaks are usually found in water bodies. Notice that Proba band 1 is discarded by the model. The atmospheric model is less accurate for the IR region since values are too low to the sensor sensitivity below the S/N ratio.

ASD FieldSpec on the site signature vs. Proba 0º reflectance Quick evaluation shows an overall underestimation of water reflectance for the bands in the visible range (2-14). Bands in the Near IR (15-16) are fairly coupled to on-the-ground measures but 17 and 18 bands are overestimated according to such measures. Nonetheless, overall spectral behaviour in the VIS range fits the characteristic spectral signature of water bodies. IR reflectance values are not very accurate.

Simple Geometric correction of Proba images and ground-truth 1st degree geometric correction was applied by establishing 9 ground control points fairly spread across the scene what ensures RMS below 1 pixel for 90% of the pixels. Coincident field campaign was carried out over different flooding and plant-covered levels in 3 accessible sites indicated by red circles RMS values increase for images captured with a high satellite zenith angle as well as for high observation angles Proba RGB (17-15-9) of Doñana North (15/12/2006)

Some pictures on the ground-truth variability wet waterlogged Shallow inundation, variable plant cover and turbidity

Preliminary results on flooding level: spectral separability Band 18 located in the Infrared (1025 nm) shows the best spectral separability for all the flooding levels, unless for the separability between waterlogged and damp, which corresponds to Band 14 (710 nm). Overall, as for other sensors the presence of water is mainly discriminated with IR bands

Preliminary results on % water cover: spectral separability Again, Band 18 in the IR offers the best spectral separability for percent water cover. Only for low water covered pixels B15 and B14 yield better separabilities (0% vs 1-5% and 5-25% vs 1-5% respectively).

Preliminary results on % emergent plant cover: spectral separability Again, Band 18 in the IR offers the best spectral separability for percent emergent plant cover, the most abundant plant type in the marsh in springtime. The following bands allowing to discriminate % plant cover are B12 (683 nm) and B6 (563 nm) corresponding to photosynthetic pigments peaks that should be recommended for composing a Vegetation Index

Preliminary results on water turbidity: spectral separability of NTU classes Although quantitatively measured, NTU has been classified in order to check spectral separability. Band 14 (710 nm) is the best band to discriminate turbidity classes. This band supports the hypothesis that turbidity is mainly due to fitoplancton since it corresponds to photosynthetic activity peaks. However, classes are not properly ranked by B14 unlike B2 and B3 which in addition accumulates the maximum global separability across the turbidity gradient.