Synergies between the Surface Biology and Geology and the Aerosols, Clouds, Convection and Precipitation: science, applications, societal benefits, models, algorithms and measurements

In 2018 the decadal survey by the US National Academy of Sciences recommended a series of high priority Earth observations for NASA. Two missions, the Surface Biology and Geology (SBG) and Aerosols, Clouds, Convection and Precipitation (ACCP), are core components of NASA's Earth System Observatory to acquire these observations. They both address planetary-scale science questions spanning fluxes of energy, aerosols and water across the surface and atmosphere. They also pursue overlapping applications and societal benefits in public health, agriculture, water resources, ecosystems and natural hazards. This paper explores synergistic research strategies for these common objectives, in terms of measurements, retrieval algorithms and models. We recommend that airborne campaigns pair the aerosol properties and multiangle polarimetric surface reflectance measurements with VSWIR spectroscopy for the best analysis of both the atmosphere and surface. Underlying these measurements are laboratory, suborbital and lunar calibration, for which assets and strategies should be shared. For algorithm development, we propose to generate a common set of tests and benchmarks. In doing so, optimizing the tradeoff between speed and accuracy of radiative transfer is a high priority. A variety of models exploit measurements and retrievals and, in turn, guide them. We recommend that the interactive development proceed with particular focus on global distribution of aerosol species and optical properties as well as geophysical variables such as surface mineral maps. All these joint activities promise further collaborations and a deeper understanding of the Earth as a system.