Retrieval of PAR-estimates under heterogeneous atmospheric conditions using remote sensing data and radiation transfer models

A new method is proposed for retrieving the photosynthetically active radiation (PAR) using remote sensing data (AVHRR) and a radiation transfer model (libRadtran). The approach applicable for clear and cloudy sky conditions takes into account atmospheric parameters affecting the radiation transfer through the atmosphere, namely, extinction by aerosols and clouds. AVHRR data from May to September 1999 were processed and analyzed. The results are validated with ground truth data. It is shown that a good correlation exists between measured and estimated PAR values for clear and cloudy sky conditions over Europe for different daily time intervals.