Cooperative Institute for Climate Science News – Winter 2015

Contributed by Joanne Curcio for PEI ・ Princeton Environmental Institute

CICS Associate Director Sonya Legg, an AOS faculty member, is coauthor of a new article featured in a special issue of Oceanography “Women in Oceanography: A Decade Later.” The article “The Impact of MPOWIR: A Decade of Investing in Mentoring Women in Physical Oceanography” describes the MPOWIR (Mentoring Physical Oceanography Women to Increase Retention) Program, a US community-initiated and community-led mentoring program aimed at improving the retention of women physical oceanographers in academic and/or research positions. It also describes MPOWIR’s impact to date and outlines its future directions. Legg, who has taken an active role in supporting and mentoring women and early career scientists at Princeton, is one of MPOWIR’s lead Principal Investigators.

Other CICS news includes two recent publications:

In a new study led by CICS Scientist Pu Lin, an AOS postdoctoral research associate, GFDL global climate models were used to investigate how the Brewer-Dobson circulation would vary in response to different natural and anthropogenic climate forcings. Tropical air has less ozone than polar air, even though the tropical stratosphere is where most atmospheric ozone is produced. The Brewer-Dobson circulation is considered key to understanding this apparent contrast. The authors calculate the strengths of the Brewer-Dobson circulation simulated by GFDL global climate models CM3 and CM2.1, and find that the strengths correlate with the tropical mean surface temperature. This correlation is also supported by observational-based analysis. Yi Ming, a lecturer in Department of Geosciences and the AOS Program, and GFDL Director V. Ramaswamy are coauthors of the study published in Geophysical Research Letters.

Figure 1
Scatter plot of the strength of the Brewer-Dobson circulation shallow branch versus the tropical-mean surface temperature in CM3. (a) For the interannual timescale in the control simulation. ENSO-neutral years are marked by red dots. (b) For the decadal to multi-decadal timescale in the control and historical forced simulations. Climatological means are removed. The gray line marks the result from the idealized experiment in which SST is globally uniformly increased by 4K.


CICS Scientist He Wang, a graduate student in the AOS program, is the lead author of a recent study published in Ocean Modelling that describes the sensitivity of the North Atlantic climate in GFDL models to the model representation of the Nordic Sea overflows (flows of dense water through gaps in the ridge between Greenland and Scotland). These flows are usually poorly captured in coarse resolution climate models. Wang and coauthors CICS Associate Director Sonya Legg and Robert Hallberg, an AOS faculty member, find that the Meridional overturning circulation, the direction of the warm North Atlantic Current, and the temperature and salinity of the northernmost part of the Atlantic can all be affected. This is the first study to carefully compare old and new methods of capturing the overflows in climate models, and to show the importance of representing these flows accurately in order to correctly simulate the climate in the North Atlantic.