Shweta Bhati

Analysis of WRF Model Performance over Subtropical Region of Delhi, India

Model performance and sensitivity to model physics options are studied with the Weather Research and Forecasting model (version 3.1.1) over Delhi region in India for surface and upper air meteorological parameters in summer and winter seasons. A case study with the model has been performed with different configurations, and the best physics options suited for this region have been, determined. Comparison between estimated and observed data was carried out through standard statistical measures. Generally, the combination of Pleim-Xiu land surface model, Pleim surface layer scheme, and Asymmetric Convective Model has been found to produce better estimates of temperature and relative humidity for Delhi region. Wind speed and direction estimations were observed best for MM5 similarity surface layer along with Yonsei University boundary layer scheme. Nested domains with higher resolutions were not helpful in improving the simulation results as per the current availability of the data. Overall, the present case study shows that the model has performed reasonably well over the subtropical region of Delhi.

Emission Inventory of Air Pollutants and Trend Analysis Based on Various Regulatory Measures Over Megacity Delhi

© 2012 Mohan et al., licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Emission Inventory of Air Pollutants and Trend Analysis Based on Various Regulatory Measures Over Megacity Delhi

Wind Flow Conditions as an Indicator to Assimilative Capacities of UrbanAirsheds towards Atmospheric Pollution Potential

Wind flow conditions play an important role in the assimilative capacities of urban airsheds. It is desired that urban planners associate due importance to wind flow conditions while designing the cities considering its likely impact on ambient air quality. Further, considering the explosive growth of megacities across the world it is required to rank these cities as per their assimilative capacities where wind flow conditions can play an important role. This study scrutinizes wind flow conditions (stagnation, ventilation and recirculation), associated air quality and emissions for two megacities namely, Delhi and Mumbai to illustrate the pivotal role, the meteorology could play in location of urban airsheds. The study shows a dominance of stagnation conditions with few cases of recirculation events over Delhi. Ambient levels of pollutants were found to correlate positively with stagnation conditions in Delhi. Mumbai was found to have higher ventilation and recirculation events and lower ambient levels of the pollutants. Further, this study for two megacities demonstrated that persistently poor air flow conditions for an urban airshed could lead to poorer air quality even with lower emissions (Delhi) in comparison to a city with lower pollution potential and higher emissions (Mumbai). Simple methodologies as adopted here could be practiced to scrutinise carrying capacities of the cities and to rank these for their pollution potential that could be helpful to regulators for emission control strategies.