Climate Center Spring 2012 Lecturer

Climate Center Spring 2012 Lecturer

Gideon Henderson, Oxford University

26 - 30 March 2012

Please note that Gideon Henderson of Oxford University is the Climate Center Visitor for Spring 2012 (March 26 - 30, 2012).  Dr. Henderson will give two lectures on the LDEO campus on Monday and Wednesday, March 26 and 28 and one lecture on the GISS campus on Tuesday, March 27; the titles and abstracts are listed below. Since Gideon is a former LDEO researcher, he prefers to make his own schedule.  If you would like to meet with Gideon during his stay, please email him directly <Gideon.Henderson at earth.ox.ac.uk>.

General Information about Dr. Henderson's research can be found on his web page: <http://www.earth.ox.ac.uk/~gideonh>

Monday, March 26 at 3 PM in Monell Auditorium (reception to follow at 4pm in the Lower Lobby Monell)
Stalagmites grow up:  Quantifying climate processes with cave geochemistry

Stalagmites are wonderful recorders of climate, but their geochemistry is difficult to uniquely interpret.  I will describe recent Oxford research which uses stalagmites to quantify past change.   Two examples will be the reconstruction of past Asian permafrost during the last 500kyr, and annually resolved records of the response of the Asian monsoon to abrupt climate change.  I will also discuss how we are seeking to develop new stalagmite geochemical proxies, and how these efforts provide information about fractionation of oxygen and calcium isotopes in nature.



Wednesday, March 28 at 11 AM in Comer First Floor Seminar Room

Rating the oceans:  U-series and UK-GEOTRACES
Natural U-series isotopes provide information about the rates of many critical processes in the oceans.  With a focus on the modern ocean, this talk will discuss how we can use Th isotopes to assess dust fluxes to the modern ocean; Ra isotopes to assess off-shelf and deep-ocean mixing; and how the controversial proxy for circulation rate, 231Pa/230Th, is controlled in the oceans.   These examples will be set in the context of understanding micronutrient cycles of the South Atlantic – a key objective of efforts within the UK-GEOTRACES programme.

*Tuesday, March 27 at 11 AM in 3rd Floor Conference Room (GISS Campus)
Seasonal paleoclimate records:  The Mediterranean and beyond
We can now probe paleoclimate archives at sufficiently high resolution to quantify past seasonal amplitude.  This has been possible with corals in the tropics for some years, but now extends to the whole ocean through use of shells such as limpets, and to the continents using stalagmites.  This talk will demonstrate the power of this approach using a reconstruction of the seasonal cycle for the last-glacial-maximum for the Western Mediterranean using limpets (and briefly with stalagmite data from China). PMIP models fail to capture observed Mediterranean changes.  I will suggest ways in which modelling can both motivate and learn from such seasonal resolution paleoclimate observations.

*If you plan to attend the GISS lecture, please note that you must sign in and show your CU ID at the Security Desk.