Evaluating a Moist Isentropic Framework for Poleward Moisture Transport: Implications for Water Isotopes Over Antarctica
The ability to identify moisture source regions and sinks and to model the transport pathways that link them in simple yet physical ways is critical for understanding climate today and in the past. Using water tagging and isotopic tracer experiments in the Community Earth System Model, this work sho...
| Published in: | Geophysical Research Letters |
|---|---|
| Main Authors: | , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Geophysical Research Letters
2019
|
| Subjects: | |
| Online Access: | http://hdl.handle.net/1828/11918 https://doi.org/10.1029/2019GL082965 |
| Summary: | The ability to identify moisture source regions and sinks and to model the transport pathways that link them in simple yet physical ways is critical for understanding climate today and in the past. Using water tagging and isotopic tracer experiments in the Community Earth System Model, this work shows that poleward moisture transport largely follows surfaces of constant moist entropy. The analysis not only provides insight into why distinct zonal bands supply moisture to high‐ and low‐elevation polar sites but also explains why changes in these source regions are inherently linked to changes in temperature and rainout. Moreover, because the geometry, and specifically length, of the moist isentropic surfaces describes how much integrated rainout occurs, the analysis provides a physical framework for interpreting the isotopic composition of water in poleward‐moving air, thus indicating how variations in moisture transport might influence Antarctic ice cores. This material is based upon work supported by the National Center for Atmospheric Research, which is a major facility sponsored by the National Science Foundation under Cooperative Agreement 1852977. H. K. A. S. is grateful for generous funding through the Linus Pauling Distinguished Postdoctoral Fellowship, sponsored by Pacific Northwest National Laboratory and the U.S. Department of Energy Office of Science. J. N. was supported by the NASA Post‐doctoral Program (NPP) fellowship at NASA GISS, along with NASA grant NNH13ZDA001N‐NEWS. The authors thank Cecilia Bitz and David Noone for encouraging us to pursue this line of research, Robert Fajber for useful theoretical discussions, Isla Simpson and Christina McCluskey for their thoughtful feedback on an initial draft of the manuscript, and Bradley Markle and an anonymous reviewer for their excellent suggestions for improving the analysis and its presentation. CESM output data used in this study are available online (https://doi.org/10.5281/zenodo.2595607). Faculty Reviewed |
|---|