INSPIRE DTP Research Placement at Climate & Global Dynamics (CGD), NSF NCAR, Boulder CO, USA
University of Southampton & National Oceanography Centre, Southampton, United Kingdom
Thanks to the support from the Challenger Society Student Travel Award, I was able to spend the fall of 2025 on a research placement at the Climate & Global Dynamics (CGD) Laboratory, NSF National Centre for Atmospheric Research (NCAR) in Boulder, Colorado. Their contribution supported my visit alongside funding from NERC through the INSPIRE Doctoral Training Partnership, making this research placement possible. From August to November 2025, I worked with the Oceanography and Climate Analysis Sections at NCAR to investigate the changing dynamics of the Indian Ocean Dipole and its connection to the Indonesian Throughflow, using high-resolution coupled climate model simulations produced with the Community Earth System Model (CESM) under the CESM MESACLIP project.
The Indo-Pacific is one of the most dynamically influential regions in the global climate system, driving large-scale patterns of heat, moisture and atmospheric circulation. Within this region, the Indian Ocean Dipole (IOD) is a major coupled mode of variability with far-reaching impacts, shaping rainfall extremes, monsoon behaviour in the Austral-Asian region and broader climate teleconnections beyond. Its evolution is strongly affected by the Indonesian Throughflow (ITF), which links the Pacific and Indian Oceans by transporting warm, low-salinity waters into the south-eastern Indian Ocean and altering the background state on which IOD events develop. Despite continued research, uncertainty remains over how these processes will respond to continued greenhouse warming, providing a strong motivation for this study.
During my placement, my analysis centred on high-resolution and low-resolution CESM model ensembles to examine how IOD behaviour and ITF transport may change under future warming. IOD characteristics such as event frequency, intensity, periodicity, zonal structure of sea surface temperature (SST) anomalies, and seasonal evolution were evaluated using the Dipole Mode Index, which captures the anomalous SST gradient between the western and eastern equatorial Indian Ocean. To assess ITF transport changes, I analysed volume and heat transports across the major pathways that define the throughflow and its branches, including the Makassar, Lombok, and Ombai Straits, the Timor Passage, and the IX1 transect, using observational estimates as a benchmark for model performance under historical forcing and future warming scenarios. Furthermore, the inter-basin coupling between the IOD, ITF and the El Niño-Southern Oscillation was assessed on a seasonal to inter-annual time scales using lead-lag correlations.
These diagnostics allowed me to separate changes driven by mean state warming from those reflecting shifts in variability and revealed several emerging patterns: the model ensembles analysed project more frequent and earlier peaking positive IOD events, a weakening of negative IOD occurrences, and a marked reduction in ITF transport dominated by reduced Makassar inflow from the Pacific. Comparison of the high and low resolution configurations showed that high-resolution models better capture observed IOD amplitude and ITF pathway structure, while the low-resolution counterpart overestimates variability and underrepresents key transport branches. Working within the CGD environment also gave me the experience of processing large high-resolution ocean model datasets at native grid, implementing analysis workflows on parallel computing systems, and understanding how model configuration and resolution influence Indo-Pacific variability across scenarios.
The collaborative research environment at NCAR played a crucial role in improving my technical experience with large-scale climate model analysis. Working within the Oceanography and Climate Analysis Section exposed me to discussions on model configurations and setup choices, analysis methods, and resolution-dependent behaviour of climate systems. I gained practical experience handling large ensemble CESM output, running computationally intensive diagnostics on parallel systems, and developing reproducible workflows for high-resolution model simulation analysis. These interactions strengthened my ability to work efficiently with complex coupled model datasets and provided training that will directly support several other aspects of my PhD research. Outside the scientific work, the Mesa Lab, where I was based, offered a unique and engaging research environment. Interacting with scientists from a range of modelling and observational backgrounds, attending seminars, and participating in group activities added depth to the placement.
This placement has been a valuable opportunity for me to strengthen my technical skills in working with high-resolution model output, parallelised workflows, and ensemble-based climate analysis. The work undertaken at NCAR forms the basis of an ongoing manuscript, and the methods and insights developed during the visit will continue to shape how I approach model evaluation and interpretation. To conclude, I remain grateful to the Challenger Society for Marine Sciences for supporting this research placement, and I look forward to interacting and contributing to the society in the future.
Awardee Profile:
I am a third-year PhD student jointly hosted by the School of Ocean & Earth Science at the University of Southampton and the National Oceanography Centre, funded through NERC’s INSPIRE Doctoral Training Partnership. My thesis, “Evolution of the El Niño–Southern Oscillation in a Warming Climate and its Impact on Climate Extremes”, examines the projected dynamical evolution of ENSO and its teleconnections under greenhouse warming in current-generation climate models. My broader research interests include high-resolution ocean modelling, ocean-climate interactions, climate extremes, large-scale modes of variability, and AI/ML applications in oceanography and climate science.
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