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Brianna Pagán     Graduate Student or Post Graduate 
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Brianna Pagán published an article in February 2019.
Top co-authors
Diego G. Miralles

80 shared publications

Laboratory of Hydrology and Water Management, Ghent University, Coupure links 653, 9000 Gent, Belgium

Brecht Martens

24 shared publications

Laboratory of Hydrology and Water Management, Ghent University, Coupure Links 653, 9000 Ghent, Belgium

Wouter H. Maes

15 shared publications

Laboratory of Hydrology and Water Management, Ghent University, Coupure links 653, 9000 Gent, Belgium

Publication Record
Distribution of Articles published per year 

Total number of journals
published in
Article 0 Reads 1 Citation Exploring the Potential of Satellite Solar-Induced Fluorescence to Constrain Global Transpiration Estimates Brianna R. Pagán, Wouter H. Maes, Pierre Gentine, Brecht Mar... Published: 18 February 2019
Remote Sensing, doi: 10.3390/rs11040413
DOI See at publisher website ABS Show/hide abstract
The opening and closing of plant stomata regulates the global water, carbon and energy cycles. Biophysical feedbacks on climate are highly dependent on transpiration, which is mediated by vegetation phenology and plant responses to stress conditions. Here, we explore the potential of satellite observations of solar-induced chlorophyll fluorescence (SIF)—normalized by photosynthetically-active radiation (PAR)—to diagnose the ratio of transpiration to potential evaporation (‘transpiration efficiency’, τ). This potential is validated at 25 eddy-covariance sites from seven biomes worldwide. The skill of the state-of-the-art land surface models (LSMs) from the eartH2Observe project to estimate τ is also contrasted against eddy-covariance data. Despite its relatively coarse (0.5°) resolution, SIF/PAR estimates, based on data from the Global Ozone Monitoring Experiment 2 (GOME-2) and the Clouds and Earth’s Radiant Energy System (CERES), correlate to the in situ τ significantly (average inter-site correlation of 0.59), with higher correlations during growing seasons (0.64) compared to decaying periods (0.53). In addition, the skill to diagnose the variability of in situ τ demonstrated by all LSMs is on average lower, indicating the potential of SIF data to constrain the formulations of transpiration in global models via, e.g., data assimilation. Overall, SIF/PAR estimates successfully capture the effect of phenological changes and environmental stress on natural ecosystem transpiration, adequately reflecting the timing of this variability without complex parameterizations.
CONFERENCE-ARTICLE 29 Reads 0 Citations Satellite observed solar induced fluorescence to monitor global plant stress Brianna Pagán, Brecht Martens, Wouter Maes, Diego Miralles Published: 10 November 2017
Proceedings of First International Electronic Conference on the Hydrological Cycle, doi: 10.3390/CHyCle-2017-04874
DOI See at publisher website ABS Show/hide abstract

Biophysical feedbacks on climate depend on plant responses to stress conditions. Yet current land surface models (LSMs) still treat plant stress rudimentarily, and typically assume the same sensitivity to soil moisture for all vegetation types. There is a need therefore to investigate the dynamics of vegetation stress at the global scale, both to further understand the effect of land feedbacks on climate, as well as to improve the representation of these processes in LSMs. Solar induced fluorescence (SIF) is a subtle glow of energy emitted by vegetation during photosynthesis. Recently, satellite observations of SIF have been shown to closely mimic the spatiotemporal variability of photosynthesis. Given the nexus between photosynthesis and transpiration through the opening and closing of stomata, a link between SIF observations and evaporation can be hypothesised. Here, we introduce a novel index of evaporative stress (i.e. the ratio of actual to potential evaporation) based on satellite SIF observations, and we compare it to the estimates of evaporative stress by various LSMs from the Earth2Observe database (i.e. JULES, HTESSEL, ORCHIDEE). Results of validations against in situ evaporative stress – calculated from the FLUXNET2015 eddy-covariance archive – indicate that our SIF-based stress index outperforms the estimates of the LSMs across the majority of sites, with the exception of regions with sparse vegetation in which bare soil evaporation dominates the flux of vapour from land to atmosphere. SIF derived stress greatly outperforms over densely forested regions, and shows a high skill to capture leaf-out periods. Overall, this novel SIF application provides improvements for large-scale estimates of transpiration and can be used to further understand vegetation–atmosphere feedbacks from different ecosystem types. Furthermore, the implications of this research are relevant to (a) the hydrology and climate modelling communities, given the opportunity to utilise our SIF-based evaporative stress to benchmark model representation of the land control over the atmospheric demand for water, and (b) the remote sensing community, that will see how an observation originally intended for the study of the carbon cycle is valorized through its application to study water cycle dynamics as well.