AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Comparison of Model Simulated Ammonia with Observations: A Case for Implementation of Improved Gas/Aerosol Partitioning Schemes
ARSHAD NAIR, Gan Luo, Fangqun Yu, University at Albany
Abstract Number: 673 Working Group: Regional and Global Air Quality and Climate Modeling
Abstract Ammonia plays a key role in our atmosphere by virtue of its alkaline nature. It comes mainly from agriculture, and has sources in industrial and vehicular emissions. In the recent years, there has been increase in the concentration of gaseous ammonia. This has generated worry about negative impacts on the climate and human health. Especially so in the formation of smog due to its reaction with acidic species in the atmosphere. Additionally, ammonia receives increasing attention because of its potential to enhance new particle formation in the atmosphere. In this regard, it is pertinent to evaluate if models are sufficiently capturing the change in ammonia. We examine GEOS-Chem simulated ammonia concentrations with ground-based and remote sensing measurements. Our preliminary results over the continental United States, using the Ammonia Monitoring Network for ground based observations and Atmospheric Infrared Sounder (AIRS) aboard NASA’s Aqua satellite, indicate that simulated ammonia concentrations are generally lower when compared to observed values. This underestimation is also pronounced in the warmer months. We present this analysis, also extended over other regions by incorporating data from other sources including the UK National Ammonia Monitoring Network, and remote sensing by instruments such as the Infrared Atmospheric Sounding Interferometer (IASI) aboard ESA’s MetOp satellite and Tropospheric Emission Spectrometer (TES) aboard NASA’s Aura satellite. By evaluating the model estimated ammonia over the global, regional, and local scales, we hope to uncover factors that may improve such simulated concentrations of ammonia. This may indicate scope for further improvement of gas-particle partitioning schemes, even at a higher cost of computation, towards more reliable performance of global 3D tropospheric chemistry models.