Numerical Simulation of Sea Ice, Ocean Circulation and Marine Biogeochemistry in the West Antarctic Peninsula

Wednesday, September 27, 2017 | 2:30pm, 401 Akasofu

Cristina Schultz’s talk will discuss the following:

Over the past several decades, the West Antarctic Peninsula (WAP) has undergone physical and ecological changes at a rapid pace, with winter air temperatures warming up to 4.8 times the global average rate. The effects of this warming are felt by the ecosystem, with substantial decadal changes in the phytoplankton chlorophyll patterns and a poleward shift of ice-dependent species. Recent research has found a consistent trend of shortening in the sea-ice season along the WAP, associated with changes in the wind pattern. The mechanisms behind these drastic climate changes are not fully understood and have been investigated by the Palmer-LTER (Long Term Ecological Research) program over the past two and a half decades.

In this context, numerical modeling is a powerful tool, given the weather and sea ice constraints on data acquisition in the region. A high-resolution ocean circulation model, coupled to sea-ice and biogeochemistry modules, was implemented for the WAP to simulate the decadal trends and seasonal cycles of sea-ice advance, mixed layer depth and bloom formation as marked by chlorophyll and other biogeochemical tracers. The model used is MITgcm (general circulation model) coupled with REcoM-2 (Regulated Ecosystem Model, version 2). The model results were compared to the data collected by the Palmer-LTER data. General seasonal pattern of chlorophyll, nutrients and inorganic carbon variables simulated (DIC and Alkalinity) are consistent with the observations, with onshore-offshore and north-south gradients well represented. Further sensitivity analyses to be performed on the biogeochemical model will allow us to interpret the mechanisms behind changes in the ocean chemistry and ecosystem.