|Abstract : || |
The sensitive ecosystem of the Himalaya, particularly the central Himalayan (CH) region, is experiencing enhanced stress from anthropogenic forcing that requires adequate atmospheric observations and an improved representation of the Himalaya in the models. However, the accuracy of atmospheric models remains limited in this region due to highly complex mountainous topography. The convective-permitting scale simulations by the limited area models e.g., Weather Research and Forecasting (WRF) model, are broadly used for a wide range of applications, including climate projections, weather predictions, and air quality forecasts. Such state-of-the-art models fill the gap in data scarcity over high mountain areas like Himalaya. Their evaluation with observations and fine-tuning increases the certitude of the generated regional scale information. The investigation here first delineates the effects of spatial resolution on the modeled meteorology & dynamics over the CH by utilizing the Weather Research and Forecasting (WRF) model and extensively evaluated against the ground-based, remote-sensing, and re-analysis products. This analysis highlights that the WRF model set up at finer spatial resolution can significantly reduce the biases in simulated meteorology, and such an improved representation of CH can be adopted through domain feedback into regional-scale simulations. Model simulation implementing a high-resolution (3s) topography input (SRTM) improved the model performance. Further, the impact of the model physics schemes related to the sub-grid scale turbulence (six boundary layer schemes) and microphysical processes (seven microphysics schemes) are evaluated over this region. Cloud microphysics schemes are used to simulate the spatio-temporal distribution of the precipitation, especially at the convection-permitting scales, and are generally one of the major sources of uncertainty. Additionally, the impact of the enhanced aerosol loading on the surface layer characteristics has been investigated using micrometeorological measurements over the CH. In my thesis pre-submission talk, I will present a detailed analysis of the methodology and results related to the aforementioned objectives.