Energetic Particle Precipitation in the Atmosphere: Northern Hemisphere Variability and Transport

• Main Author: Holt, Laura A.
• Format: Text
• Language: unknown
• Published: CU Scholar 2013
• Subjects: atmospheric modeling; energetic particle precipitation; middle atmosphere; odd nitrogen; polar night; remote sensing; Atmospheric Sciences
• Online Access: https://scholar.colorado.edu/atoc_gradetds/36; https://scholar.colorado.edu/cgi/viewcontent.cgi?article=1038&context=atoc_gradetds

It is well understood that chemical processes in the stratosphere lead to the destruction of ozone (O3). Our interest in these processes is twofold: (1) stratospheric O3 shields the Earth from biologically harmful radiation, and (2) O3 is a radiatively active gas largely responsible for the temperature structure of the middle atmosphere. A subset of chemical processes that is particularly relevant to O3 consists of catalytic cycles. Catalysts destroy O3 without being depleted. The NOx (NO + NO2) catalytic cycle dominates in the middle stratosphere. One source of stratospheric NOx is energetic particle precipitation (EPP), which contributes to the stratospheric odd nitrogen (NOy) budget in the polar winter. Through interaction with O3, NOx created by EPP (EPP-NOx) has the potential to affect not only the composition of the middle atmosphere but, since O3 is a radiatively active gas, temperature and dynamics as well. This leads to the following science questions, which are the questions that motivated my dissertation: (1) How much EPP-NOx is transported to the stratosphere from year to year? (2) What are the important transport processes involved? The research described here focuses on answering the first question through quantification of the amount of EPP-NOx reaching the northern hemisphere stratosphere using satellite data and the second question through state-of-the-art climate simulations designed to elucidate the important transport mechanisms.