No abstract

The implementation of a nationwide lockdown to curb the spread of COVID-19 disease has reduced the loading of anthropogenic aerosols. However, AOD distribution over South Asia during the lockdown period shows a dipole pattern: reduction over North Indian and enhancement over the Myanmar region. This dipole pattern is evident in some datasets (MODIS, MERRA, and CALIPSO). MODIS fire counts collocated with CALIPSO smoke aerosols show enhancement over Myanmar indicating the contribution from fires. However, over the North India region number of fires during the lockdown period are less compared to climatology. Thus, the observed reduction in AOD is due to fires and anthropogenic sources. Our analysis shows that aerosols originating from biomass burning forms a layer (900–600 hPa) over the Myanmar region that produces atmospheric heating (0–2.8 K/day) that eventually leads to cloud dissipation/burning (negative in-atmospheric cloud radiative forcing ∼ −13 W/m2) and precipitation reduction (−1 to −4 mm) over Myanmar. In contrast, the aerosol reduction over North India favors cloud formation, that is, increase in cloud cover and reduction in specific cloud liquid water content leading to precipitation enhancement, indicating the anti-Twomey effect.

Global urban population is projected to double by 2050. This rapid urbanization is the driver of economic growth but has environmental challenges. To that end, there is an urgent need to understand, simulate and disseminate information about extreme events, routine city operations and long term planning decisions.This paper describes an effort underway in India involving an interdisciplinary community of meteorology, hydrology, air quality, computer science from national and international institutes. The urban Collaboratory is a system of systems for simulating weather, hydrology, air quality, health, energy, transport and economy, and its interactions. Study and prediction of urban events involve multi-scale observations and cross-sector models; heterogeneous data management and enormous computing power. The consortia program (NSM_Urban) is part of ‘weather ready cities’, under the aegis of India’s National Supercomputing Mission.The ecosystem ‘Urban Environment Science to Society (UES2S)’, builds on the integrated cyberinfrastructure with a science gateway for community research and end-user service with modeling and inter-operable data. The Collaboratory has urban computing, stakeholder participation, and a coordinated means to scaffold projects and ideas into operational tools. It discusses the design and the utilization of the High Performance Computing (HPC) as a science cloud platform for bridging urban environment and data science, participatory stakeholder applications and decision making. The system currently integrates models for high impact urban weather, flooding, air quality, and simulating street and building scale wind flow and dispersion. The program with the work underway is ripe for interfacing with regional and international partners and this paper provides an avenue towards that end.