Akshara Kaginalkar

An early experience of regional ocean modelling on intel many integrated core architecture

Ocean modelling is an inherently complex phenomenon within the earth system framework which poses a challenge to the earth and computational scientists. Simulation of wide temporal and spatial scales in real-time / near real-time necessitates computational scientists to explore new performance enhancing architectures and simulation methods. Due to the spectra of the scales of motion, the computational requirements of ocean forecasting are relatively higher than that of numerical weather prediction. To some extent, the rapidly evolving computer technology provide solutions to this. In this paper, we present initial attempts in porting a high resolution regional ocean model on an Intel MIC based hybrid system. We discuss the challenges and issues to be addressed in achieving an efficient implementation of an ocean modelling system.

Study of machine round-off response on weather forecasting simulations using high performance computing systems

The weather forecasting model T80L18 is found to be sensitive to variations in the computing platform. The global spectral model simulations variation due to machine round-off is examined using rounding mode analysis and the perturbation methods. The perturbation simulations of machine round-off correctly estimates the error bounds of the T80L18 weather forecasting model.

A study of Himalayan extreme rainfall events using WRF-Chem

The rising number of extreme rainfall events over the Himalayan foothill states of India during the recent decades has become a serious issue with the growing concern of aerosol influences. This study intends to provide some insight into aerosol and gas chemistry responses to changes in monsoon circulation and precipitation, and also assess the impact of aerosols on two recent infamous heavy rainfall events using coupled meteorology–chemistry–aerosol (WRF-Chem) model simulations. The sensitivity of aerosols and chemistry on rainfall distribution and the amount is evaluated using the simulations with and without chemistry. Results from this study show that the magnitude and spatial distribution of precipitation are significantly influenced by including aerosol and gas chemistry in the model simulations. Realistic meteorological conditions as well as rainfall amount and distribution are reproduced when aerosols and gasses are taken into account in the simulation. There is an overall enhancement of total cumulative rainfall as high as 20% due to aerosols and gas chemistry over the western Himalayan Indian states. This study shows that cloud-microphysical properties and the resulting precipitation distribution depend critically on the aerosol types and their concentrations under similar thermodynamic conditions. This study highlights the role of aerosol and gas chemistry and recognizes the importance of atmospheric chemistry in the model simulation for the analysis of Himalayan extreme precipitation events, and its further associations with the Himalayan hydrology.