Earth and Planetary Sciences ETDs

Publication Date

Summer 7-3-2019


Recent studies have shown water vapor isotopologues to be sensitive tracers of mixing processes that govern low-cloud feedback in climate models. In this study, we develop an inverse model (MBL Mix inverse model) that uses one year of isotope and humidity observations from Graciosa Island, Azores to estimate mixing for four seasons. We show the dry end-member of the model, the lower free troposphere (LFT), can be represented using Rayleigh fractionation. Isotope observations from Graciosa Island are compared to other field locations to discuss controls on isotopic variability other than mixing. Output from the MBL Mix inverse model shows the lowest (highest) fractions of seasonal-scale average mixing correspond to months previously observed to have the highest (lowest) occurrence of low-clouds. The model additionally shows a minimum mixing of approximately 0.3 is required to match observed data in all seasons in the Azores.

Degree Name

Earth and Planetary Sciences

Level of Degree


Department Name

Department of Earth and Planetary Sciences

First Committee Member (Chair)

Dr. Joseph Galewsky

Second Committee Member

Dr. David Gutzler

Third Committee Member

Dr. Zachary Sharp




climate change, water vapor isotopologues, mixing

Document Type