This project has completed its objective through a combination of next-generation modelling tools, advanced statistical techniques and a breadth of observations. During the project lifetime, a convection-permitting ocean-atmosphere coupled system was configured for the region of interest and a range of model experiments were completed at one of the most powerful supercomputers. Sophisticated technical and statistical approaches were used to distill useful information from the massive amount of data generated by the modelling system. A range of observational products including satellite-derived estimates, gauge measurements and radar information were used to provide a backdrop for model comparison and evaluate its performance.
Finally, information from multiple Global Climate Models was gathered to generate a climate change signal used to force the fine-scale modelling system and establish the future evolution of rainfall and related processes.
As a result of this, we have shown the adequacy of the atmospheric modelling system to study rainfall and convection in the Maritime Continent. We established the need of very high-resolution modelling techniques and representing convection explicitly to realistically simulate precipitation in the tropics. We showed that the model is able to capture the main characteristics of rainfall in the region, both over land and over the ocean. Challenges remain in terms of the excess of rainfall produced by the model over land, an issue shared by other modelling systems, while the key aspects such as the diurnal cycle were clearly improved at convection-permitting scales.
We identified mechanisms that contribute to correctly represent rainfall-generating processes in the region such as the moisture convergence on land due to water vapor availability in the lower levels of the atmosphere, the vertical structure of deep clouds and the generation of non-precipitating shallow convection. We show the limited effect of resolution and convection on the representation of sea breeze and thus concluded that differences in rainfall estimates are not produced by how the model represents this local circulation.
We found that the use of ocean-atmosphere regional climate models in the region requires further development since the sea surface temperature was prone to systematic biases that in turn lead to substantial precipitation errors. However, we also showed that the diurnal variation of sea surface temperature may play a non-negligible role in modulating rainfall processes and thus should be taken into account when studying convection in the region.
We also explored the relationship between temperature, dew-point temperature and precipitation extremes in the Maritime Continent using a convection-permitting model and multi-model climate change signal to quantify its future evolution. We concluded that near-surface temperature or dew-point temperature, and their changes, are not representative of the entire column temperature and its changes, which may produce apparent inconsistencies with the Clausius-Clapeyron scaling for precipitation.
During this project, I published three peer-reviewed articles in international journals and submitted other three that are currently under review. I also made contributions to 3 international conferences, 1 international workshop and 2 seminars, and was invited to two talks aimed at the general public. Overall, the project produced enormous amount of data (140TB) and code, some of which were shared through public repositories. Videos and written pieces explaining aspects of deep convection in the Maritime Continent were shared through the project website and my personal website. I have visited three world renowned institutions in the US (NCAR), France (CNRS) and Australia (UNSW) and collaborated with multiple international researchers these and other institutions (Newcastle University, KNMI).
