PAOC Colloquium: Liz Moyer (University of Chicago)
"Using in-situ measurements of the water vapor isotopic ratio to understand convective transport in the Asian Summer Monsoon"
The Asian monsoon is one of the world’s largest weather systems, and is often claimed to be a significant pathway by which water enters the stratosphere. Satellite measurements of water vapor isotopic ratio, a strong tracer of convective origin, have however suggested significant differences in transport behavior between the Asian and North American monsoons, with strong isotopic enhancement, occurring only over North America. We report here on preliminary results from the July/August 2017 StratoClim campaign, in which instruments aboard the high-altitude M-55 Geophysica aircraft made the first in-situ tracer measurements in the upper troposphere/lower stratosphere region over the Asian Monsoon. The payload included the new Chicago Water Isotope Spectrometer (Chi-WIS), which measures HDO and H2O; its measurements confirm the distinct isotopic signature of the Asian monsoon. Both isotopic and other tracers suggest a reason: while the Asian monsoon experiences frequent convective up to 400 K potential temperature, there appears to be limited overshoot above this level. Convection-driven water vapor perturbations from the Asian monsoon may therefore provide only a limited contribution to the overall stratospheric water budget.
About the Speaker
My research interests fall in two main threads. The first includes the use of the isotopic composition of atmospheric water vapor as a tracer of convective processes, cirrus formation, and stratosphere-troposphere exchange; and the design of spectroscopic techniques for in-situ trace gas measurements. The second includes climate (and human) response to greenhouse-gas forcing; development of tools for impacts assessment; statistical emulation of climate model output; and climate and energy policy evaluation.
About this Series
The PAOC Colloquium is a weekly interdisciplinary seminar series that brings together the whole PAOC community. Seminar topics include all research concerning the physics, chemistry, and biology of the atmospheres, oceans and climate, but also talks about e.g. societal impacts of climatic processes. The seminars generally take place on Monday from 12-1pm. Lunch is provided to encourage students and post-docs to meet with the speaker. Besides the seminar and lunch, individual meetings with professors, post-docs, and students are arranged.