Articles | Volume 17, issue 7
Research article
03 Apr 2017
Research article |  | 03 Apr 2017

Comparing multiple model-derived aerosol optical properties to spatially collocated ground-based and satellite measurements

Ilissa B. Ocko and Paul A. Ginoux

Abstract. Anthropogenic aerosols are a key factor governing Earth's climate and play a central role in human-caused climate change. However, because of aerosols' complex physical, optical, and dynamical properties, aerosols are one of the most uncertain aspects of climate modeling. Fortunately, aerosol measurement networks over the past few decades have led to the establishment of long-term observations for numerous locations worldwide. Further, the availability of datasets from several different measurement techniques (such as ground-based and satellite instruments) can help scientists increasingly improve modeling efforts. This study explores the value of evaluating several model-simulated aerosol properties with data from spatially collocated instruments. We compare aerosol optical depth (AOD; total, scattering, and absorption), single-scattering albedo (SSA), Ångström exponent (α), and extinction vertical profiles in two prominent global climate models (Geophysical Fluid Dynamics Laboratory, GFDL, CM2.1 and CM3) to seasonal observations from collocated instruments (AErosol RObotic NETwork, AERONET, and Cloud–Aerosol Lidar with Orthogonal Polarization, CALIOP) at seven polluted and biomass burning regions worldwide. We find that a multi-parameter evaluation provides key insights on model biases, data from collocated instruments can reveal underlying aerosol-governing physics, column properties wash out important vertical distinctions, and improved models does not mean all aspects are improved. We conclude that it is important to make use of all available data (parameters and instruments) when evaluating aerosol properties derived by models.

Short summary
Human-made liquid and solid particles (aerosols) are abundant in the atmosphere and play a central role in climate change. Computer models are essential tools for understanding how aerosols impact the climate, but it is critical to evaluate a model's performance by comparing with observations. Here we analyze aerosol properties in two world-renowned models by comparing with ground-based and satellite instrument data. We find that comparisons with all available data is valuable and essential.
Final-revised paper