Chemical Weather and Chemical Climate

Abstract

Progress in fundamental understanding of atmospheric chemistry in the past decades has enabled the development of advanced environmental predictive capability. Accurate chemical weather forecasts and source attribution information can play a decisive role in mitigating the short‐term exposure of the public to acute air pollution episodes. Chemical climate projections will allow investigation of the long‐term consequences of human choices and their impact on the future evolution of the Earth system. This commentary stresses the importance of integrating atmospheric chemistry in operational environmental prediction and projection systems.

Projections of Future Air Quality Are Uncertain. But Which Source of Uncertainty Is Most Important?

“…When modeling future air quality, studies have largely focused on scenario uncertainty and uncertainty due to diversity in model response. Brasseur and Kumar (2021) explain that future air quality studies have tended to neglect uncertainty due to internal climate variability because traditional atmospheric chemistry transport models do not exhibit chaotic behavior. The complexity of chemistry schemes with hundreds of species and chemical reactions have meant that only recent advances in computing capabilities have led to ESMs with detailed interactive chemistry being used increasingly.…”

“…Meteorology and composition are tightly coupled. Besides controls on composition through large‐scale and regional transport and local mixing, numerous chemical processes of production and destruction and deposition rates are influenced by meteorology (e.g., Brasseur & Kumar, 2021). Natural emission rates too are often influenced by meteorology, oceans and the biosphere.…”

Nonlinear and Non‐Gaussian Ensemble Assimilation of MOPITT CO

“…Capturing spatio‐temporal variability of atmospheric constituents is important for both short‐term air quality monitoring and multi‐scale chemical weather forecasting (e.g., Brasseur & Kumar, 2021), as well as supporting chemistry‐climate applications (e.g., Staniaszek et al., 2022). Carbon monoxide (CO) plays a central role in tropospheric chemistry.…”