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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-23 17:41 |
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Conference: Bucharest University Faculty of Physics 2014 Meeting
Section: Atmosphere and Earth Science; Environment Protection
Title:
In-situ and satellite reflectance measurements for drought vegetation monitoring in Caracal study area
Authors:
Laura MIHAI(1), A.STANCALIE(1), Adelina SPOREA(1), D.SPOREA(1),
Argentina NERTAN(2), Denis MIHAILESCU(2)
Affiliation:
1)National Institute for Laser, Plasma and Radiation Physics, Atomistilor 409, Magurele, Ilfov, Romania
2)National Meteorological Administration 97, Soseaua Bucuresti-Ploiesti, sector 1, Bucharest, Romania
E-mail
laura.mihai@inflpr.ro
Keywords:
vegetation drought, reflection, vegetation indices
Abstract:
Drought monitoring and plant growth can be qualitatively evaluated using vegetation indices (VIs). VIs, like the Normalized Difference Vegetation Index (NDVI), Normalized Difference Water Index (NDWI) and the Normalized Difference Drought Index (NDDI) are very important tools for vegetation discrimination and correlations with biophysical parameters that determine the vegetation state. These indices can be calculated from in-situ and satellite reflectance measurements that have to be done with a high precision.In this paper we present some results obtained in the DROMOSIS project, (developed in the frame of Space Technology and Advanced Research Program - STAR 2012), regarding the use of satellite and in-situ measurements for agricultural drought monitoring. High (Pleiades) and mid resolution satellite data (TERRA/MODIS si SPOT/Vegetation), agro-meteorological data and reflectance in-situ data were used. Two measurements campaigns were organized in the Caracal study area, with an interval of two weeks between them, in order to obtain the spectral properties of different types of crops plants (corn, sunflower), their leaf area index (LAI), fraction of absorbed photosynthetical active radiation (fAPAR) and soil moisture.For in-situ reflectance measurements an optical fiber system consisting of three different spectrometers covering the spectral range UV to NIR, a very precise reflectance standard and two cosine collectors was used. For each data acquisition period, we considered different measurements points for each type of vegetation, investigated from different angles of view. Results showed differences in reflectance (from two consecutive campaigns) in the ranges of 400 nm to 500 nm and 690 nm to 750 nm. These differences can be related to phenological changes of studied canopy. The in-situ results, correlated with main agro-meteorological parameters (temperature, soil moisture and precipitation) proved to be good indicators of the drought vegetation condition.
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