Sachin Patade

• Ph.D.
• Researcher at Lund University

Convective clouds are ubiquitous over the tropics and midlatitudes, and they are part of aggregated convection. The convection is initially driven by the boundary layer eddies and the fair-weather cumulus, which gets favored by the vertical ascent. The deep convective clouds in the Indian monsoon environment, as inferred from the in situ measuremen...

Much of the initiation of ice particles in deep precipitating clouds has been attributed to Secondary Ice Production (SIP). Fragmentation during collisions among particles of ice precipitation is one of the known SIP processes. Some recent studies have used our theoretical formulation of this SIP process in the cloud microphysics scheme of numerica...

The accurate representation of mixed-phase monsoon clouds and their phase distribution is of great importance for numerical models used to predict monsoon rainfall. Therefore, it is essential for these models to correctly capture the phase fraction of clouds, which includes the proportions of liquid and ice. Ice particle formation in clouds occurs...

A new microphysics treatment that includes aerosol-cloud interactions and secondary ice production (SIP) mechanisms is implemented in the convection scheme of the Community Atmosphere Model, version 6 (CAM6). The approach is to embed a 1-D Lagrangian parcel model in the bulk convective plume of the existing deep convection parameterization. Aerosol...

Secondary Ice Production (SIP) has been attributed to the generation of most ice particles observed in precipitating clouds with cloud tops warmer than −36 °C, from various aircraft and ground-based field observations across the globe. One of the known SIP mechanisms is fragmentation during collisions among ice particles. It has been studied with o...

Ice formation remains one of the most poorly represented microphysical processes in climate models. While primary ice production (PIP) parameterizations are known to have a large influence on the modeled cloud properties, the representation of secondary ice production (SIP) is incomplete and its corresponding impact is therefore largely unquantifie...

The unique in situ measurements of clouds and precipitation within the shallow and deep cumulus over the north-eastern Arabian Sea region during the Indian monsoon are illustrated in this study with a focus on droplet spectral parameters. The observational period showed a significant incursion of Arabian dust and the presence of giant cloud condens...

Precipitation in clouds can form by either warm-rain or ice crystal processes, referred to as warm and cold formation pathways, respectively. Here, we investigate the warm and cold pathway contributions to surface precipitation in simulated continental convective storms. We analyze three contrasting convective storms that are cold-based, slightly w...

The role of time-dependent freezing of ice nucleating particles (INPs) is evaluated with the ‘Aerosol-Cloud’ (AC) model in: 1) deep convection observed over Oklahoma during the Midlatitude Continental Convective Cloud Experiment (MC3E), 2) orographic clouds observed over North California during the Atmospheric Radiation Measurement (ARM) Cloud Aero...

Global climate models (GCMs) are challenged by difficulties in simulating cloud phase and cloud radiative effect over the Southern Ocean (SO). Some of the new‐generation GCMs predict too much liquid and too little ice in mixed‐phase clouds. This misrepresentation of cloud phase in GCMs results in weaker negative cloud feedback over the SO and a hig...

A new empirical parameterization (EP) for multiple groups of primary biological aerosol particles (PBAPs) is implemented in the aerosol–cloud model (AC) to investigate their roles as ice nucleating particles (INPs). The EP describes the heterogeneous ice nucleation by (1) fungal spores, (2) bacteria, (3) pollen, (4) detritus of plants, animals, and...

Various mechanisms of secondary ice production (SIP) cause multiplication of numbers of ice particle, after the onset of primary ice. A measure of SIP is the ice enhancement ratio ( ‘IE ratio’ ) defined here as the ratio between number concentrations of total ice (excluding homogeneously nucleated ice) and active ice nucleating particles (INPs). A...

Precipitation is fundamental to the hydrological cycle. There are two possible mechanisms for its formation in clouds generally: the "warm-rain process" and the "ice crystal process". This study uses a microphysically advanced aerosol-cloud (AC) model to understand the contributions from the warm (from the warm-rain process) and cold (from the ice...

A new empirical parameterization (EP) for multiple groups of primary biological aerosol32 particles (PBAPs) is implemented in the aerosol cloud model (AC) to investigate their roles as ice-nucleating particles (INPs). The EP describes the heterogeneous ice nucleation by (1) fungal spores, (2) bacteria, (3) pollen, (4) detritus of plants, animals, a...

This study examines precipitation pathways in different thermodynamic and aerosol environments over the Indian peninsula. A three-dimensional idealized Large-Eddy Simulation (LES) model with spectral bin microphysics is used to simulate the convective clouds growing under different monsoon environments. Numerical simulations were evaluated using in...

In Part I, an electrification scheme was described and a simulation of an observed cold-based storm from the US High Plains was validated with electrical observations. Most charge in the storm was separated by rebounding collisions of secondary ice originating from prior graupel-snow collisions. In this Part II, sensitivity tests are performed with...

Ice fragments are generated by sublimation of ice particles in subsaturated conditions in natural clouds. Conceivably, such sublimational breakup would be expected to cause ice multiplication in natural clouds. Any fragment that survives will grow to become ice precipitation that may sublimate and fragment further. As a first step towards assessing...

For decades, measured ice crystal number concentrations have been found to be orders of magnitude higher than measured ice-nucleating particle number concentrations in moderately cold clouds. This observed discrepancy reveals the existence of secondary ice production (SIP) in addition to the primary ice nucleation. However, the importance of SIP re...

To resolve the various types of biological ice nuclei (IN) with atmospheric models, an extension of the empirical parameterization (EP) (Phillips et al. 2008; 2013) is proposed to predict the active IN from multiple groups of primary biological aerosol particles (PBAPs). Our approach is to utilize coincident observations of PBAP sizes, concentratio...

Airborne observations conducted during the Northeast Monsoon onset as part of the Cloud Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX 2011) are used to link the activation properties of aerosols with the observed cloud microphysics from the cloud base to cloud top. This study illustrates the significant spatial variability i...

For decades, measured ice crystal number concentrations have been found to be orders of magnitude higher than measured ice nucleating particles in moderately cold clouds. This observed discrepancy reveals the existence of secondary ice production (SIP) in addition to the primary ice nucleation. However, the importance of SIP relative to primary ice...

In this two-part paper, influences from environmental factors on lightning in a convective storm are assessed with a model. In Part I, an electrical component is described and applied in the Aerosol-Cloud model (AC). AC treats many types of secondary (e.g. breakup in ice-ice collisions, raindrop-freezing fragmentation, rime-splintering) and primary...

Observations during the Ice in Clouds Experiment‐Tropical (ICE‐T) field experiment show that the ice particles concentration in a developing deep convective clouds at the level of T = −15 °C reached about 500 L−1, that is, many orders higher than that of ice‐nucleating particle. To simulate microphysics of these clouds, the 2‐D Hebrew University Cl...

Observations during the Ice in Clouds Experiment‐Tropical (ICE‐T) field experiment show that the ice particles concentration in a developing deep convective clouds at the level of T = −15 °C reached about 500 L⁻¹, that is, many orders higher than that of ice‐nucleating particle. To simulate microphysics of these clouds, the 2‐D Hebrew University Cl...

The effect of warm microphysical properties on ice processes is investigated in developing monsoon (MON) and premonsoon (PRE) cumulus clouds growing under different thermodynamic and aerosol conditions. We used airborne observations of cloud microphysical properties during the Cloud Aerosol Interaction and Precipitation Enhancement Experiment (CAIP...

Influence of the environmental thermodynamics on the microphysics of deep cumulus clouds over different parts of India is studied using in situ airborne observations from the Cloud Aerosol Interaction and Precipitation Enhancement EXperiment (CAIPEEX) during 2009. This study provides an understanding of the thermodynamics–microphysics relation over...

A numerical formulation is provided for secondary ice production during fragmentation of freezing raindrops or drizzle. This is obtained by pooling laboratory observations from published studies and considering the physics of collisions. There are two modes of the scheme: fragmentation during spherical drop freezing (mode 1) and during collisions o...

The Weather Research and Forecasting (WRF) Model coupled with a spectral bin microphysics (SBM) scheme is used to investigate aerosol effects on cloud microphysics and precipitation over the Indian peninsular region. The main emphasis of the study is in comparing simulated cloud microphysical structure with in situ aircraft observations from the Cl...

A comprehensive analysis of particle size distributions measured in situ with aircraft instrumentation during the Cloud Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX) are presented. In situ airborne observations in the developing stage of continental convective clouds during premonsoon (PRE), transition (TRA), and monsoon (M...

The thermodynamical and microphysical response during the transition from southwest to northeast monsoon season is studied. Unique mixed phase cloud observations from the Cloud Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX) and ground based observations from Integrated Ground Observation Campaign (IGOC), high resolution (3 k...

A thermal gradient diffusion chamber (TGDC) designed to process the ice nuclei (IN) sample is illustrated with unique airborne observations. IN samples collected during the Cloud Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX) have been analyzed using the TGDC. The TGDC is able to activate the IN by deposition mode over ice s...

The combined effect of humidity and aerosol on cloud droplet spectral width (s) in continental monsoon clouds is a topic of significant relevance for precipitation and radiation budgets over monsoon regions. The droplet spectral width in polluted, dry premonsoon conditions and moist monsoon conditions observed near the Himalayan Foothills region du...

Aerosol and cloud microphysical observations were conducted during the Cloud Aerosol and Precipitation Enhancement experiment (CAIPEEX) over the Indian subcontinent. The observations characterized highly polluted to clean aerosol regimes during the premonsoon dry conditions to moist monsoon conditions. These observations give a unique opportunity t...