Estimation of photosynthetically active radiation absorbed at the surface
نویسندگان
چکیده
منابع مشابه
New developments in the remote estimation of the fraction of absorbed photosynthetically active radiation in crops
[1] The fraction of absorbed photosynthetically active radiation, fAPAR, is an important biophysical characteristic in models of gas exchange between the terrestrial boundary layer and the atmosphere, as well as in the analysis of vegetation productivity. Synoptic estimation of fAPAR has been performed by using NDVI as a linear proxy of fAPAR, despite the saturation of NDVI at fAPAR beyond 0.7....
متن کاملResponse of Canopy Solar-Induced Chlorophyll Fluorescence to the Absorbed Photosynthetically Active Radiation Absorbed by Chlorophyll
Solar-induced chlorophyll fluorescence (SIF), which can be used as a novel proxy for estimating gross primary production (GPP), can be effectively retrieved using ground-based, airborne and satellite measurements. Absorbed photosynthetically active radiation (APAR) is the key bridge linking SIF and GPP. Remotely sensed SIF at the canopy level (SIFcanopy) is only a part of the total SIF emission...
متن کاملfAPAR (fraction of Absorbed Photosynthetically Active Radiation) estimates at various scale
This paper reviews the several methods available for estimating the fAPAR, both at local and large scale. The fAPAR definition is first discussed with regards to the directionality of the incident radiation. Then, the several techniques to estimate fAPAR from local ground measurements are reviewed with emphasis on the sampling strategy. We then describe methodologies to upscale fAPAR measuremen...
متن کاملEstimation of leaf area index and the fraction of absorbed photosynthetically active radiation in a boreal forest
The aim of this dissertation is to assess the accuracy of different ground reference methods used to validate satellite based leaf area index (LAI) and the fraction of absorbed photosynthetically active radiation (fPAR) products. LAI and fPAR are strongly linked, although they principally and practically measure different properties: LAI quantifies the areal interphase between soil and atmosphe...
متن کاملEstimation of photosynthetically active radiation under cloudy conditions
Clouds are the largest modulators of the solar radiative flux reaching the Earth’s surface. The amount and type of cloud cover prevailing at a given time and location largely determines the amount and type of solar radiation received at the Earth’s surface. This cloud radiative forcing is different for the different solar spectral bands. In this work, we analysed the influence of cloud radiativ...
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ژورنال
عنوان ژورنال: Journal of Geophysical Research: Atmospheres
سال: 1997
ISSN: 0148-0227
DOI: 10.1029/97jd01219