Looking forward to keep working with you all in 2018!
Over the last decade, a few space missions have shown that the tinny chlorophyll fluorescence signal that emanates from all higher plants can be seen from space. These missions however had very coarse resolutions (with e.g. 100km2 pixels) which greatly limited their scientific utilization.
OCO-2 is one of NASA’s new satellites from which solar-induced fluorescence (SIF) can be retrieved whithin a Fraunhofer line located around 760nm. In a recent Science paper, Sun et al. demonstrate the new capabilities of OCO-2 derived SIF which, at a spatial resolution of 1×2 km, can already yield meaningful SIF values that show particulartly good correlations with tower-based measurements of gross primary productivity. In this study we assess the future potential and challenges for the interpretation of SIF data sources that are continuously increasing in quality and resolution. In this context, OPL is currently working towards the mechanistic understanding of multiscale SIF drivers, in preparation for future hi-resolution satellite data. See Full PDF in our Publication Section.
Remote Sensing acquires optical data across space and time. We then want to interpret the data in terms of spatial and temporal variation in plant functional or biochemical traits. In a recent paper (Atherton et al. 2017, see publications) we investigated the background spatial variation in key optical properties/traits like the photochemical reflectance index or the shape and intensity of the leaf chlorophyll fluorescence spectra and the factors that control it. We found that both the light environment within plant canopies and the species generate background spatial variability in the above optical traits which needs consideration when interpreting remotely sensed data.
Anu Riikonen has recently joined our Lab. She just finished her PhD studies and will help us coordinating the project “Cost-effective methods for tracking large scale vegetation physiology (see projects)”. We will certainly benefit from her expertise with field ecophysiological measurements and stakeholder interaction.
By the way, Anu will also give a hand with the website so it probably start to look gradually better 🙂
Cost-effective methods for tracking large scale vegetation physiology: Participatory phase and pilot experiments
Society faces the challenge of an increasing population that concentrates in urban areas. Food production needs to be increased following sustainability criteria for optimal use of water, fertilizers and pesticides. Air pollution and human stress are an increasing problem in urban areas which could be also improved through detailed management and expansion of urban forests and parks. These challenges require new and cost-effective tools to track the health status of vegetation.
With the advent of unmanned aerial vehicles (UAVs) and hyperspectral imaging systems it might be now possible to acquire detailed information on vegetation health and physiological status anywhere and anytime. In this project we will evaluate the potential of advanced optical indices (emission of chlorophyll fluorescence and other fine variations in vegetation reflectance) to monitor vegetation health using UAVs. We will conduct pilot campaigns both in city parks as well as in farms. Stakeholders include: the City of Helsinki, the Finnish Geospatial Institute, the Natural Resources Institute of Finland, as well as private partners from the hyperspectral sensor industry and agricultural sectors.
See more details in the Section PROJECTS
From now on you can follow our most recent updates in twitter:
Paulina Rajewicz joined our Lab this week. She will study the processes that control the leaf-level variation in leaf optical properties as part of FLUOSYNTHESIS project and her PhD studies.
We have an open PhD-student position to join our Lab. Application deadline is 8th April 2016.
The new team member will study the factors that control the variation in leaf optical traits across space, time and species as part of our FLUOSYNTHESIS project.
Further details and instructions of how to apply from this link:
Light absorption is the first step of photosynthesis. However, measuring light absorption may be a challenge in certain types of leaves, such as needles. We propose to do it by painting the leaves with black spray prior to measurement in an integrating sphere. Check our recent paper in Tree Physiology for more details (See Publications).
Chlorophyll fluorescence and the Photochemical Reflectance Index (PRI) are related to rapid time-scale adjustments in the photosynthetic machinery. However the relationship between photosynthetic rate and these measurements has not been fully elucidated, even at the leaf scale. We conducted leaf level modelling and measurements of the dynamics of spectral chlorophyll fluorescence and the PRI, and showed that these measurements can be combined to estimate photosynthetic efficiency parameters. We recommend future strategies to scale to the canopy and landscape (you can find a PDF in our “Publications” section).
Thanks to the University of Helsinki Funds and the Academy of Finland for support!