There is a need to quantify aerosol optical depth verses proportion of direct/diffused solar radiation

There is need to quantify photosynthetic efficiency as related to direct or diffused radiation, although with photosynthetic system researchers evaluated photosynthesis rates diurnally (point observations), but may have limitations in extending to field conditions on regional scales

regards

Dear Naveen

Between 5 to 10 percent increase has been reported for different crop when they have been produced in greenhouses covered with high haze covers. According to previous studies, one of the main issues that improve production under high haze covers is  increased canopy photosynthesis. Diffused radiation would cause more even distribution of light inside the canopy and result in increase in the photosynthesis of leaves located in the middle and lower levels of the canopy. In this case the photosynthesis of the leaves located in the top of the canopy will not change, while the decreased photosynthesis of the lower part of the canopy (due to the shading created by the top layer leaves) would recovered due to increased light incidence on the lower levels. This improving effect of the diffuse light on greenhouse crops has been reported for roses, tomato and cucumber as far as I know.

Please have a look on the recent paper of my colleague regarding your question

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4559655/

Dear Sasan

thanks a lot, I agree with you regarding more interception of radiation (fraction of total at that time) by the canopy, which induces higher photosynthetic efficiency, we need to quantify this effect for developing a sub-routine to be added in the crop simulation models

regards

Thanks Abhishek for nice papers, aerosol presence and SPM within the atmosphere cause decrease in sunshine hours, but the radiation is not reduced to that extent, it gets modified into proportion of direct/diffused parts, how these components behaves with the crop processes, such as photosynthesis, respiration due to coupled weather changes, phenology, partitioning and others for subsequently working out the impacts

These studies/observations most of the time are under controlled conditions, with limited leaf/canopy monitoring and carefully need to be taken on field/regional scales, still are very useful for deriving the relationships, which could further be used for climate change studies

thanks for uploading excellent papers

regards