Turbulence-induced droplet grouping and augmented rain formation in cumulus clouds.

This paper provides the first observational analysis of how droplet separation is impacted by the flinging action of microscale vortices in turbulent clouds over a select radii range and how they vary over cloud cores and along the peripheral edges. It is premised that this mechanism initiates droplet separation within a cloud volume soon after condensational growth, largely in the cloud core, and operates until the cloud droplet radii exceed 20-30 µm when this effect fades rapidly. New observations are presented showing how microscale vortices also impact the settling rates of droplets over a critical size range (6-18 µm) causing them to sediment faster than in still air affecting swept volumes and thereby impacting the rain initiation and formation.

Generalized Scaling and Model for Friction in Wall Turbulence.

We present a novel generalized scaling framework and predictive model for wall friction in turbulent flows. The scaling is derived from the dynamical equations, and total mean-flow kinetic energy and the velocity profile shape factor are used as surrogates for dynamical and boundary condition effects. Veracity of the present approach is assessed using data from the literature spanning unprecedented ranges of flow types, Reynolds numbers, accelerations, and history effects.

Characteristics of elevated aerosol layer over the Indian east coast, Kattankulathur (12.82N, 80.04°E): A northeast monsoon region.

The elevated aerosol layer (EAL) plays a vital role in weather and climate by modifying the Earth's radiation budget. In the present study, the EAL occurrence and its characteristics in the pre-monsoon season using micropulse lidar (MPL) observations during 2016-2018 and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) during 2007-2018 over Kattankulathur is being reported. We have collected 147 days (101 cases) of MPL (CALIPSO) observations during clear sky conditions in the pre-monsoon 2016-2018 (2007-2018), out of which EAL is observed for 56 days (61 cases).

Clouds and Convective Self-Aggregation in a Multimodel Ensemble of Radiative-Convective Equilibrium Simulations.

The Radiative-Convective Equilibrium Model Intercomparison Project (RCEMIP) is an intercomparison of multiple types of numerical models configured in radiative-convective equilibrium (RCE). RCE is an idealization of the tropical atmosphere that has long been used to study basic questions in climate science. Here, we employ RCE to investigate the role that clouds and convective activity play in determining cloud feedbacks, climate sensitivity, the state of convective aggregation, and the equilibrium climate.

Characterization of atmospheric trace gases and water soluble inorganic chemical ions of PM and PM at Indira Gandhi International Airport, New Delhi during 2017-18 winter.

Water soluble inorganic chemical ions of PM and PM and atmospheric trace gases were monitored simultaneously on hourly resolution at Indira Gandhi International Airport (IGIA), Delhi during 8 December 2017-10 February 2018. Monitoring was made by MARGA (Monitoring AeRosol and Gases in ambient Air) under winter fog experiment (WIFEX) program of the Ministry of Earth Sciences (MoES), Government of India. The result based on the analysis of the data so generated reveals that Cl, NH, NO and SO were dominant ions in order which collectively constituted 96.