Events

UTIG Brown Bag: Cornelia Rasmussen

Informal weekly presentations by UTIG students and researchers. Bring your lunch!

WATCH A RECORDING OF THE TALK

Speaker: Cornelia Rasmussen, Postdoctoral Fellow, UTIG

Title: Cause and Effect – Why Understanding the Timing of Key Earth History Events Matters

De Ford Lecture Series: Jessica (JC) Crevling

UTIG Seminar Series: Isla Simpson, NCAR

Speaker: Isla Simpson, Scientist 1, Climate and Global Dynamics Division, National Center for Atmospheric Research (NCAR)

Hosts: Yuko Okumura and Patrick Heimbach

Title: Multi-decadal variability in the North Atlantic jet stream, its connection to ocean variability and the implications for decadal prediction.

Abstract: The characteristics of the North Atlantic jet stream play a key role in the weather and climate of western Europe. While much of the year to year variability in the jet stream arises from internal atmospheric processes that are inherently unpredictable on timescales beyond a few days to weeks, any low frequency variability that can be considered forced by slowly varying boundary conditions, offers the potential for extended range predictability of climatological conditions in western Europe. Here it will be demonstrated that over the historical record, the North Atlantic jet stream has displayed pronounced multi-decadal variability in the late winter with implications for precipitation in western Europe. This jet stream variability far exceeds that found in state-of-the-art climate models and far exceeds expectations from the sampling of atmospheric noise. It is found that over the observational record there is a strong connection between Sea Surface Temperature (SST) variability and jet stream variability in the North Atlantic and that this connection appears to be absent in models. Nevertheless, given that models can predict SST variability at long lead time, the observed SST-jet stream-precipitation relationship combined with model predicted SST variability offers the potential for extended range predictability of low frequency precipitation variability in western Europe.

DeFord Lecture: Sedimentary Geology candidate

De Ford Lecture Series: Gary Mavko

UTIG Seminar Series: Beth Christensen, Rowan University

Speaker: Beth Christensen, Professor of Environmental Sciences, Rowan University

Host: Stephen Phillips

Title: How Plate Tectonics Drove Continental Climate Change In Australia

Abstract: Plate tectonics have a strong influence on large scale oceanic circulation, creating basins and altering flow through time. Despite plate tectonics operating on a very different scale from climate, it is becoming increasingly clear that small and incremental tectonic change can have a major influence on climate. Before the uplift of the Maritime Continent, the Indonesian Throughflow allowed for waters to move easily from the tropical Pacific to the Indian Ocean. Drilling on the northwest margin of Australia (IODP Expedition 356) allowed us to document the timing and impact of restriction of the Indonesian Throughflow in the middle Pliocene.

Analysis of Expedition 356 slope and shelf sediments indicates northwest Australia was humid in the early Pliocene. The progressive restriction of the Indonesian Throughflow greatly impacted Australian climate, depriving much of the continent of the abundant humidity available earlier. This shift to a climate similar to the modern began in the mid Pliocene (~3.5 Ma). By ~2.4 Ma, dust records indicate northwest Australia had an arid climate with strong seasonal rains. The restriction also influenced Indian Ocean circulation, with significant changes in the surface and deep waters. Regional changes in the northeast Indian Ocean are coincident with east African climatic shifts and so the restriction may, in turn, have influenced human evolution, as predicted by earlier modeling studies.

Dr. Christensen is Professor and Chair of the Rowan University Department of Environmental Science. She received her PhD, which focused on Leg 150 sediments, from University of South Carolina. Beth has worked on deep sea sediments ever since, sailing on a total of 4 expeditions (Leg 150, 166, 175 and 356).