Since the spring of 2005, scientists working for the Institute of Systems Biology and Ecology (ISBE) from the Czech Academy of Sciences have been focusing on research aimed at designing a physically-based algorithm to scale spectral and spatial data on vegetation, which is relevant to the development of the Sentinel-2 mission.

Map of total chlorophyll content (Cab)generated from the hyperspectral airborne AISA Eagle sensor (pixel-size 0.4 m) acquired in 2004 over Norwegian spruce at the Bily Kriz research site in the Czech Republic.

Credits: Institute of Systems Biology and Ecology (ISBE)

As one of a series of operational Earth Observation satellites planned as the space segment of GMES, Sentinel-2 will be a multispectral optical imaging mission for terrestrial applications and will provide continuity to the current Landsat and Spot satellites guaranteeing the availability of data to service providers and users. Formulating algorithms so that the eventual retrieved data is of optimum use is an important part of this new mission's preparatory activities.

The research into this new algorithm is focused on the forests of Norwegian spruce (Picea abies (L.) Karst.) growing within montane and boreal ecosystems. Boreal forest is one of the largest types of biomass on Earth, therefore, research into the dynamics of the carbon cycle within this ecosystem and forest management are of scientific and economic importance. It is expected that the research carried out in the Czech Republic will result in a clearly defined procedure for retrieving chlorophyll content and Leaf Area Index (LAI) from optical imagery at high spatial resolution, as will be realised from the Sentinel-2 mission.

As part of the process to define these new algorithms, a complex campaign named HYPERspectral ThREE Scalse (HYPERTREES) was carried out in August and September 2006. Data from three levels – ground, airborne and satellite level – were simultaneously collected at an experimental research site called Bily Kris (White Cross), located in the Moravian-Silesian Beskydy mountains in the eastern part of the Czech Republic. The test site is equipped with a sophisticated ground system for monitoring basic Norwegian spruce ecosystems, and includes the facilities to measure carbon dioxide fluxes with an Eddy-covariance flux tower. Three structurally different plots of the spruce were studied within the test site - one which represented a relatively young (29 year old) homogenous monoculture growing in regular patterns, and two other plots with mature forest dominated by adult spruce trees (between 75 and 110 years old) growing irregularly.

All the acquired data sets are currently being processed by researchers from ISBE in cooperation with scientists from Charles University, Prague, Czech Republic. After the appropriate pre-processing, the data will be used develop the up-scaling methods that allow the quantitative estimation of the total chlorophyll content and LAI of Norwegian spruce forests using optical satellite images of high spatial resolution such as CHRIS/PROBA and Sentinel-2.

Note: This article has been adapted from a news release issued by ESA