Hydrology of the Indian Monsoon on Millennial Timescales
OCCI Funded Project: 2007
Abstract
The
Indian monsoon affects the livelihood of over 60% of the world’s population. The monsoon is a consequence of the seasonal
temperature contrast between the Indian Ocean and the
Asian subcontinent. It strongly impacts
agricultural, transportation, health and tourism concerns for the region. Natural and human-forced variations in the
monsoon are increasingly important societal concerns. In addition to being of regional importance to
more than 3 billion people, variations in the Asian monsoon have been called
upon to explain phenomena ranging from millennial-scale changes in the tropical
hydrological cycle and emissions of greenhouse gases to million-year scale
changes in the chemistry of Earth’s oceans.It is therefore perplexing to acknowledge that we do not yet have a detailed
understanding of relatively recent (Holocene) monsoon paleohydrology.
In this study, we will perform an integrated
data and modeling study designed to begin to reconstruct the paleohydrology of
the Indian monsoon in the Bay of Bengal region. By constructing a geochemical time-series (δ18O
and Mg/Ca) of planktonic foraminifera in a new and unique sediment core, we
will estimate the magnitude of local ocean δ18O variability and infer salinity
and runoff variations that occurred in response to seasonal climate variations
in the Holocene. These data will provide
a rare record for evaluating the monsoon dynamics of an atmospheric general
circulation model similar to those used to predict future hydrological cycle
changes. This project represents the
first collaboration between Assistant Scientist Liviu Giosan and Associate
Scientist Karen Bice, which brings together expertise in climate-induced
changes in continental margin sedimentation (Giosan) and construction of
quantitative proxy climate records and climate modeling (Bice). As importantly, this project, with both
laboratory and computer modeling components, represents an important research
opportunity for Camilo Ponton, a second-year MIT-WHOI Joint Program student. The project exposes Camilo Ponton to a host
of new analytical techniques (X-ray fluorescence, stable isotope and
inductively coupled mass spectrometry, and climate modeling), it also
represents Liviu Giosan’s first foray into computer climate modeling, and Karen
Bice’s first research in sediments younger than 14 million years old.
This project directly addresses the Ocean and Climate Change Institute theme: “How do changes in the hydrological cycle affect climate on decadal to millennial time scales?”