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In our recent study in Global Change Biology (Li et al., 2018), we examined the relationship between solar‐induced chlorophyll fluo‐rescence (SIF) measured from the Orbiting Carbon Observatory‐2 (OCO‐2) and gross primary productivity (GPP) derived from eddy co‐variance flux towers across the globe, and we discovered that there is a nearly universal relationship between SIF and GPP across a wide variety of biomes. This finding reveals the tremendous potential of SIF for accurately mapping terrestrial photosynthesis globally. In a letter to the Editor, Zhang, Zhang, Joiner, and Migliavacca (2018) argued that different viewing zenith angles (VZA) of the

OCO‐2 instrument could impact the SIF‐GPP relationship revealed by our recent study. We need to clarify four over‐or misinterpretations. In the letter, Zhang et al.(2018) first explained the measurement modes of OCO‐2 (ie, nadir, glint, and target) and called for …