Formaldehyde in the Tropical Western Pacific: Chemical sources and sinks, convective transport, and representation in CAM-Chem and the CCMI models†

摘要: Formaldehyde (HCHO) directly affects the atmospheric oxidative capacity through its effects on HOx. In remote marine environments, such as Tropical Western Pacific (TWP), it is particularly important to understand processes controlling abundance of HCHO because model output from these regions used correct satellite retrievals HCHO. Here, we have observations CONTRAST field campaign, conducted during January and February 2014, evaluate our understanding distribution in TWP well representation chemical transport/climate models. Observed mixing ratios varied ~500 pptv near surface ~75 upper troposphere. Recent convective transport precursors, acetaldehyde possibly methyl hydroperoxide, increased tropospheric by ~33% (22 pptv); this air contained roughly 60% less NO than more aged air. Output CAM-Chem chemistry (2014 meteorology) nine climate models Chemistry-Climate Model Initiative (free-running are found uniformly underestimate columns derived situ between 4 50%. This likely results a factor two most models, which strongly suggests errors NOx emissions inventories and/or mechanisms. Likewise, lack oceanic potential lead additional underestimates modeled up 75 (~15%) lower