Monitoring seasonal changes in Plant Traits from the combination of Landsat-8 and Sentinel-2 time series analysis: exploring the relationship between vegetation water status and water fluxes
Spectroscopy and environmental remote sensing laboratory (SpecLab). The Spanish National Research Council
Foliar water content and associated water potential is a primary factor limiting plant transpiration and carbon uptake, therefore it forms a crucial link between the carbon, water and energy cycles. This study aims to investigate how vegetation canopy water content (CWC) is related to evapotranspiration through integration of available satellite data series (Landsat-5, Landsat-8 and Sentinel-2/3, MODIS) in combination with airborne and field information. The pilot study site for this project is located in Extremadura (Central-Western Spain). It is a well-established observational facility for ecosystem process studies with important infrastructure for continuous monitoring of ecosystem fluxes and vegetation status.
The research workplan will focus on:
Use of Radiative Transfer Models (RTM) to design vegetation indexes (VI) that are more sensitive to CWC;
Use hyperspectral data acquired at canopy level with field and remotely piloted aircraft (RPA) mounted field spectroradiometers + airborne images to improve separation of physiological and biogeochemical properties of the ecosystem components;
Develop a method to un-mix/disaggregate the spectral and thermal responses from trees and grasses in satellite images and generate time series of reflectance factors/temperature of trees and grasses by inversion of RTM using the previously unmixed signals;
Calibrate and validate the algorithms using a variety of past and on purpose field campaigns;
Apply and validate existing thermal-based evapotranspiration models (TSEB, METRIC, Triangle method, etc.) with both satellite and airborne imagery;
Evaluate spatio-temporal trends between transpiration rates and leaf/canopy water content.
This position involves two secondments:
A 3 months stay at Max Planck Institute (Germany) under the supervision of Dr. Mirco Migliavacca to learn about plant functional traits in tree-grass ecosystems.
A 3 month stay at UNIMIB (Italy) under the supervision of Drs. Roberto Colombo and Micol Rossini to learn about optical proximal sensing for vegetation monitoring.
The activity will be supervised by Dr. Maria Pilar Martín, David Riaño and Dr. Hector Nieto.