[SLS Pre-Defense] Olivia Norman

“Exploring atmospheric phosphorus sources, transport, and trends”

Phosphorus (P) is an essential nutrient that plays a key role in ecosystem productivity and, in turn, climate, water quality, and food security. Atmospheric deposition of soluble P (i.e., bioavailable phosphorus) is important in several P-limited regions (e.g., the Amazon, Mediterranean Sea) and may be impactful in many unstudied P-limited regions. Chemical transport models can be used to study the magnitude and relative importance of atmospheric phosphorus on a global scale; however, the few existing atmospheric model descriptions of phosphorus are not well-constrained. In this work, we develop a new simulation of the emissions and chemistry of atmospheric phosphorus in a global atmospheric chemistry model, GEOS-Chem. We determine that dust is the largest source of total phosphorus, but pollen produces the most soluble phosphorus. Through model-observation comparisons, we find a high bias in coarse-mode phosphorus in dust regions, indicating that phosphorus in fine and coarse dust may be better represented if treated separately. We also evaluate a long-term dataset of atmospheric phosphorus concentrations from across the US to identify trends in P associated with combustion events (fires and anthropogenic combustion), which suggests that the contribution of phosphorus from combustion is on the lower end of previous estimates.

Sack Lunch Seminar Series —
Informal seminar series within PAOC (Program in Atmospheres, Oceans, and Climate) that focuses on more specialized topics than the PAOC Colloquium. The presentations are either given by an invited speaker or by a member of PAOC and can focus on new research or discussion of a paper of particular interest.

Contact: sacklunch-committee@mit.edu