262 Advances in Ecohydrogeology (Posters)

Ecohydrogeology is the unifying, synthetic field of study integrating the approaches from the ecological and hydrogeological sciences in the study of groundwater-related ecosystems, habitats, and organisms. We encourage submissions of research that advances the science, stewardship, and policy at the intersection of ecology and hydrogeology.

Wednesday, 22 October 2025
8:00 AM - 5:30 PM
HBGCC, Hall 1

Tracking Tree Emissions from the Sky: Predicting Isoprene Estimates with MEGAN and including water-tree interactions

Paper number: 262-7
Program: Technical Sessions
Time: 8:00 AM – 8:00 AM

Authors

Abstract

Isoprene, a biogenic volatile organic compound emitted by trees, contributes to secondary pollutants like formaldehyde and ozone. Its short atmospheric lifetime (up to one hour) and complex emission dynamics make it difficult to quantify and predict. Drought adds further complexity, as recent research suggests isoprene emissions respond nonlinearly to water stress. Therefore, incorporating ecohydrological insights into isoprene modeling via water-tree interactions may improve isoprene emission estimates. This study employs the Model of Emissions of Gases and Aerosols from Nature (MEGAN) to estimate isoprene emissions in California and Missouri, two regions with contrasting vegetation types, during the summer of 2013. The predictions were compared to airborne data, specifically mixing ratios in whole air sampling, from the flight campaign Studies of Emissions and Atmospheric Composition, Clouds, and Climate Coupled by Regional Surveys (SEAC4RS) and Student Airborne Research Program (SARP) to evaluate MEGAN’s accuracy. Specifically, to parameterize MEGAN this study utilizes the North American Data Assimilation System (NDLAS) to compile a list of meteorological and surface variables. Two different models were run, one with consideration of water stress (actual evapotranspiration/potential evapotranspiration) and one without. The results of this study show airborne samples of isoprene correlate well with MEGAN-derived isoprene estimates in both regions with and without water stress consideration. In addition to this, two more models were run, one with integrating the emission factor without the water stress and one with it.  Interestingly, while most regions showed a positive correlation between the predictions with and without the water stress factor, California predictions with the stress factor exhibited a strong negative correlation. This has implications for changing the manner in which water stress is parameterized in the model. This nonlinear behavior highlights the importance of regional vegetation and climate interactions when modeling these biogenic emissions. With these findings in mind, it's beneficial to integrate ecohydrological understanding into emissions models. Isoprene emissions from airborne data has rarely been used in the context of studying drought with MEGAN, therefore this work highlights the importance of understanding and refining stress response parameters- a crucial step towards improving predictions of biogenic emissions for future climate scenarios.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6

doi: 10.1130/abs/2025AM-413567

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