I am using ERA5 database to analyze solar radiation parameters at the surface. Here I encounter the problem that I don’t understand very clear the meaning/definition of each parameter. What is the difference between total sky direct radiation at surface, surface net solar radiation and surface solar radiation downwards? I couldn’t find the answer in ERA documentation. At first , I thought that net solar radiation comprises direct and scattered radiation , hence total sky direct radiation at surface should be always less than net solar radiation. However , after loading the data it turns out that it is not always the case. That fact made me curious: how total sky direct radiation at surface may be higher than surface net solar? I have uploaded the graph to illustrate my question. Thank you!
