Arabian Sea Tropical Cyclones (TCs) occur once or twice per year on average. Yet they have significant impacts, through their intense rainfall, strong winds and storm surges, on the coastal regions of Oman, Yemen, Somalia, Pakistan and western India. For example, TCs Gonu (2007), Phet (2010) and Mekunu (2018) caused substantial deaths and economic losses. TCs can also cause severe disruption to oil and gas production, particularly in Oman where it provides 66% of their revenue. Even weaker tropical depressions can have severe impacts: e.g. depression 02A (2008) made landfall in Yemen causing deaths and disruption from extensive flooding. The formation and intensification of Arabian Sea TCs are strongly controlled by advance and withdrawal of the Asian monsoon, peaking in May/June and October/November, though a recent study found that an increase in post-monsoon TCs may happen in the future. Observational records of Arabian Sea TCs are more limited than in other ocean basins, with “Best Track” data only available from 1990 onwards and less reliable data in earlier periods. Hence, there is a need to better understand the climatology and variability of Arabian Sea TCs and how they are influenced by their environment. Moreover, the countries around the Arabian Sea have seen a recent large increase in urban populations (expected to double by 2050) and also an expansion of mineral extraction. Since sea-surface temperatures have been increasing since the 1990s and are projected to increase in the future together with sea-surface height, this will make regional populations and infrastructure more vulnerable to TCs. Hence, we need to better understand how the frequency and intensity of Arabian Sea TCs will change in the future, the reasons behind any changes (e.g. increases in ocean heat content and reduced windshear) and how they can be mitigated.
In this PhD project, the following questions will be addressed:
• What are the climatology, variability and trends of TCs in the Arabian Sea and how are they are modulated by changes in SST, the Indian monsoon and other large-scale modes of variability such as El Niño-Southern Oscillation , the Madden–Julian oscillation and Indian Ocean Dipole?
• How well are Arabian Sea TCs represented in high resolution coupled climate models and what is the impact of increased resolution on that representation, including their structure and impact-relevant properties?
• How will the climatology and variability of TCs in the Arabian Sea change in the future, what drives such changes and how will TC impacts change?
• What is the likelihood of physically plausible low likelihood high impact events?
The student will use new reanalysis products such as ERA5 and NOAA 20C V3 to answer the first question. They will also work closely with the High-Resolution Global Climate Modelling Group at NCAS and the Met Office, which will provide access to recent high-resolution climate model simulations prepared in the PRIMAVERA project and contributing to the 6th Coupled Model Intercomparison Project (CMIP6) assessed by the IPCC. Other high-resolution data will be used from the HighResMIP and SPHINX projects. These model simulations will be used to answer the questions 2 and 3. Data from large ensemble simulations, such as D4PDF and CESM-LENS, will be used to answer the last question.
We are looking for an enthusiastic student with a natural science background from subjects like meteorology, physics, environmental/Earth science, or mathematics, with demonstrated strong analytical skills and a keen interest to study the physics of tropical cyclones as well as the statistics of their occurrence and impacts. The student will also learn the necessary programming and data analysis skills required for the quantitative analysis of big climate data sets.
To discuss this PhD opportunity informally please contact Dr Kevin Hodges ([email protected]