Periodic Reporting for period 1 - FIBER (Understanding soil fertility impacts on terrestrial biomass production in a changing environment)
Periodo di rendicontazione: 2017-02-28 al 2019-02-27
Understanding vegetation sensitivity to droughts is important for estimating the impacts of extreme events and the year-to-year variations of the terrestrial carbon balance. Dry and hot periods like last year’s summer in northern Europe can negatively affect the C balance of a whole continent and thereby accelerate the man-made increase in atmospheric CO2.
The objective of this project was to develop a new method for detecting water stress on vegetation productivity, to test the widely-used assumption that atmospheric humidity provides sufficient information to capture drought effects, including soil water stress, and to characterise the drought-sensitivity of ecosystems across a wide range of climates.
In a next step, we evaluated a set of widely-used remote sensing-based models for estimating vegetation productivity across the globe and over time. The question we asked was whether these models can accurately simulate photosynthesis during soil moisture drought periods, which we have managed to identify precisely in our previous study (Stocker et al. 2018). This was an obvious question to ask because these remote sensing-based models do not account for soil moisture directly, but use information on atmospheric humidity as a proxy for dryness in general. We found that all the models we investigated had a very clear relationship with the timing and magnitude of the apparent soil moisture stress we identified earlier. This indicates that information on soil moisture should be included explicitly in estimates of vegetation productivity - not just atmospheric humidity and remotely sensed vegetation greenness. This research was published in Nature Geoscience (Stocker et al., 2019).
Apart from data analysis, this project yielded both new methods for data analysis, and new model development for global vegetation productivity simulations using a new modular modelling framework (SOFUN):
- Benjamin Stocker. (2018, April 6). sofun: v1.1.0 (Version v1.1.0). Zenodo. http://doi.org/10.5281/zenodo.1213758
All code and model outputs are made freely accessible through github (https://github.com/stineb/soilm_global https://github.com/stineb/nn_fluxnet2015 https://github.com/stineb/fvar) and on the open access permanent data repository Zenodo:
- Stocker, Benjamin. (2018). fLUE [Data set]. New Phytologist. Zenodo. http://doi.org/10.5281/zenodo.1158524
- Benjamin Stocker. (2018, February 20). nn_fluxnet2015: Final release (Version submission_3). Zenodo. http://doi.org/10.5281/zenodo.1181691
- Benjamin Stocker. (2018, April 6). sofun: v1.1.0 (Version v1.1.0). Zenodo. http://doi.org/10.5281/zenodo.1213758
- Stocker, Benjamin. (2018). GPP: Site-scale and global model outputs from P-model used for Stocker et al. (2019) Nature Geosci. (Version v1.0) [Data set]. Zenodo. http://doi.org/10.5281/zenodo.1423484
- Benjamin Stocker. (2019, January 18). soilm_global: Code for Stocker et al. (2019) Nature Geosci. (Version v1.0). Zenodo. http://doi.org/10.5281/zenodo.2543324