Scholarly record
INTEGRATING SATELLITE OBSERVATIONS WITH GROUND-BASED MEASUREMENTS TO ASSESS FOREST EVAPOTRANSPIRATION IN THE RHODOPE MOUNTAINS, BULGARIA
Abstract
Forest evapotranspiration is a key component of the water balance in mountain ecosystems and plays an important role in regulating regional hydrological processes. Accurate assessment of evapotranspiration, a key component of the water cycle, remains challenging due to the spatial and temporal variability of vegetation water use and the limitations of individual observation methods. The objective of this study is to assess forest evapotranspiration in the Rhodope Mountains (Bulgaria), simulated using the open source land surface modelling platform SURFEX, by comparing the model simulation results to satellite based estimates, and to in-situ measurements at the meteorological station of National Institute of Meteorology and Hydrology near National Astronomical Observatory Rozhen at 1759 m a.s.l. Field estimates of evapotranspiration and soil moisture derived from micrometeorological measurements and in-situ soil moisture sensors are used to provide a more detailed reference for interpreting local vegetation water fluxes. Satellite-derived products obtained from remote sensing observations, including evapotranspiration, and soil moisture, are used to explore the potential of combining in situ and satellite data for the simulation of vegetation–atmosphere interaction. The satellite products used in this study - LSA-SAF DMETv3, ETMonitor, NASA ECOSTRESS and MODIS16 - are compared with evapotranspiration measured by the eddy covariance method and with SURFEX simulation results. Soil moisture of H26 H-SAF product is compared against in-situ measurements and SURFEX results. SURFEX was applied in its one-dimensional (1D) configuration for the Rozhen observatory site. The goal is to check whether simulation results, obtained with carefully analysed meteorological input, could be improved to provide a more realistic representation of evapotranspiration, and ensure further use of the model for wider area analysis. The results are analysed at both 8 day and monthly aggregation levels. They show the similarities and divergences between the various products, the simulation results and the measurements. Most notable is the similarity between the majority of products for the period August-November and for winter months January-February. More problematic is the period April to July where the results diverge considerably. That points to the need of more specific look at the model physics, measurements and product’s discrepancies for the spring-summer period. The integration of ground-based measurements with satellite observations provides a complementary approach for assessing forest evapotranspiration and contributes to a better understanding of vegetation water use in mountain forest ecosystems.
Publication details
References13
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