Comparison with observations shows cloud simulations improving

Abstract

Climate projections, such as those used by the Intergovernmental Panel on Climate Change, rely on models that simulate physical properties that affect climate, including clouds and water vapor content. Clouds and water vapor are difficult to simulate in global climate models because they are affected by small‐scale physical processes, and cloud feedback on climate is therefore a large source of uncertainty in climate predictions. A new study finds that model simulations of vertically averaged cloud water amount have improved in recent years. Jiang et al. developed a quantitative scoring method to evaluate the accuracy of 19 climate models at various vertical heights between the surface and the tropopause (16–18 kilometers in altitude) over the tropical oceans (30°N–30°S). They compared the models' simulated multiyear mean of cloud water content and water vapor with observations made using several NASA satellites.