Atmospheric chemistry and transport: from surface air quality to the middle stratosphere
Over the last few decades, new technologies in the form of observational satellites, measurement instruments, and model simulations have enabled the scientific community to make substantial strides to understand the drivers, mechanics, and impacts of climate change. This dissertation utilizes an aggregate of these data types to produce a more comprehensive view of important atmospheric processes from earth’s surface to the middle stratosphere. Here, three focused research projects each represents a body of systematic work that carefully examines how observational and model data sets can be merged to address specific scientific questions. The first atmospheric topic in this work assesses satellite skill in detecting near-surface air quality as observed by surface measurements and hindcasted by model simulations. We find during the more extreme air quality events, ozone (O3) can propagate into large signals that are detectable by satellites. Currently, this satellite skill is regionally dependent, but with the progression of newer satellites and measurement technology, space-based surface air quality detection will improve. The second project assesses the skill of multiple models to reproduce observed variability of nitrous oxide (N2O) loss in the stratosphere. The models agree well with the satellite measurements, which gives us confidence in using them to follow the stratospheric N2O loss signal across the tropopause and down to the surface where they are compared with surface measurements. Agreement between the models and the surface observations indicate that the stratosphere plays an important role in the variability of surface N2O abundances. Lastly, we use N2O, that is well constrained by satellite and surface measurements, to assess our model skill in simulating O3 transport from the stratosphere to the surface. O3 transport from the stratosphere is difficult to quantify directly, however with N2O we create important metrics that are linked to it in order to better understand the tropospheric O3 budget. The overall goal of this dissertation is not only to address specific scientific questions, but also to develop specific observational metrics related to key Earth system processes that can provide for a grading of model performance. Such metrics can allow us to select better models for specific forecasts, and provide guidance and a historical record for future model development.