It is common that extraterrestrial solar radiation Ra value lessen due to the interaction with atmosphere components to result a net solar radiation Rn value about one third of Ra for most measurements on earth. Net solar radiation had major impact on air temperature (To) value statement. So, its estimation is crucial for analyzing the interaction of (atmosphere-vegetation-soil).
Many methodologies available for this aim directly (with radiometer) or indirectly (with air temperature-based formula or soil plus air temperatures-based formula). The peak influences of global warming phenomenon were in eighties decade of the last century, yielding Iraq Rn rates to get climax after that Rn rates behaved in geographical based style, so those rates raised in middle and south regions of Iraq, and descending in its northern parts. The reason (as demonstrated in this research) was the spatial correlation in a reverse manner with RH rates all over Iraq.
