• Project
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Overview

The Asian Monsoon is one of the best examples of coupling between land, ocean and atmospheric processes, but its evolution over tectonic time scales (millions of years) is poorly understood. There is an existing debate around ascertaining key drivers that control monsoon precipitation.

The key questions that this project will address are:

(i) understanding the interactions between geological drivers of the monsoon; tectonic uplift, greenhouse gases, ocean circulation, orbital forcing, and more.

(ii) how well do Cenozoic climate records reflect the monsoon response to those drivers?

Earth system models constrained with robust observational data provide the ideal framework to quantify and disentangle Earth system processes.  A large number of simulations can be performed that vary model assumptions. Observational data can be ‘assimilated’ into the outputs of these simulations, thereby combining these two independent sources of information.

The PLASIM-GENIE Atmosphere-Ocean General Circulation Model, recently developed at the Open University, is well suited to a comprehensive evaluation of these uncertainties. The model has the necessary atmosphere-ocean dynamics to address the problem, but it is computationally fast enough to enable many hundreds of simulations.

Different oceanic and terrestrial proxy records from Asian monsoon regions have provided conflicting evidence for the timing of initiation and/or strength of the summer monsoon, highlighting the importance of long, continuous sediment successions and robust proxies.

This project will comprise a data and modelling synthesis, with flexibility for the student to favour either pathway if appropriate.

The data element will involve the reconstruction of rainfall and runoff in response to the Indian Summer Monsoon from the core monsoon region of the Bay of Bengal (BoB), using recently drilled continuous sedimentary successions from the BoB (IODP Expedition 353) along with ongoing data generation from other recent monsoon expeditions (IODP 355, 346).

The modelling element will involve creating and analysing a large ensemble of PLASIM-GENIE simulations.

Figure 1: PLASIM-GENIE simulation of summer monsoon in the present day compared to NCEP reanalysis data

Methodology

The modelling will involve 1) The design of a collection of ‘model worlds’, varying land-sea mask, mountain topography, ice-sheets and ocean gateways. 2) The statistical design and running of a large ensemble of PLASIM-GENIE simulations. 3) The assimilation of observational data into the simulations 4) The application of state-of-the-art statistical methods such as emulation, to disentangle and quantify the relative impacts of the uncertain drivers.

The data element will identify two seasonally abundant planktonic foraminiferal species. These will then be crushed and split for (a) d18O and (b) Trace elements/Ca (e.g., Li/Ca, Mg/Ca, Ba/Ca, Cd/Ca) measurements. Coupled shell d18O and trace element data will provide data to reconstruct calcification temperature and d18O seawater (salinity) in response to rainfall and runoff.

 

Training and Skills

CENTA students are required to complete 45 days training throughout their PhD including a 10 day placement. In the first year, students will be trained as a single cohort on environmental science, research methods and core skills. Throughout the PhD, training will progress from core skills sets to master classes specific to CENTA research themes. 

Timeline

Year 1: Training in configuring, running and interpreting the outputs of PLASIM-GENIE. Training in sample processing of core material, microfossil identification and inorganic geochemical techniques in modern samples from the core-location to test methods.

Year 2: Present models output at EGU. Two weeks placement experience in an industry or public engagement. Generate records of temperature and salinity from sites U1443 and U1448 on tectonic time scale.

Year 3: Model-data comparison by assembling all the published data and synthesising new results and write up thesis and manuscripts.

Partners and collaboration (including CASE)

This project will benefit from international collaborations and networking opportunities with IODP 353 expedition scientists and scientists from other monsoon legs. In particular there will be collaboration with co-chief scientist Wolfgang Kuhnt (Germany). Wide-ranging modelling and statistcis collaborators include Klaus Fraedrich (PLASIM) and Richard Wilkinson (Bayesian statistics).

 

Further Details

Students should have an understanding of the Earth System with an enthusiasm for developing their understanding of climate models. A mathematical background is essential. Computational modelling experience and/or experience of palaeoclimate research is desirable. The student will join a well-established team researching on palaeoclimate and Earth system models at the Open University.

Please contact Phil Holden (philip.holden@open.ac.uk) or Pallavi Anand (pallavi.anand@open.ac.uk) for further information.

Applications should include:

 

Applications should be sent to

STEM-EEES-PhD-Student-Recruitment@open.ac.uk  

by 5 pm on Monday 22nd January 2018