Most studies of the effect of aerosols on cloud radiative properties have considered only changes in the cloud droplet concentration, neglecting changes in the spectral shape of the cloud droplet size distribution. However, it has been shown that that the spectral dispersion of the cloud droplet size distribution (defined as the ratio of the standard deviation to the mean radius of the droplet ...

[1] An assessment of aerosol-cloud interactions (ACI) from ground-based remote sensing under coastal stratiform clouds is presented. The assessment utilizes a long-term, high temporal resolution data set from the Atmospheric Radiation Measurement (ARM) Program deployment at Pt. Reyes, California, United States, in 2005 to provide statistically robust measures of ACI and to characterize the vari...

In this paper we present a parameterization of the nitric acid effect on cloud droplet formation. The new parameterization is intended to be used in large scale models in order to obtain regional and global estimates of the effect of nitric acid on cloud drop concentrations and the radiative balance. The parameterization is based on numerical air parcel model simulations and can be applied for ...

In-situ observations of aerosol and cloud condensation nuclei (CCN) and the GISS GCM Model II’ with an online aerosol simulation and explicit aerosol-cloud interactions are used to quantify the uncertainty in radiative forcing and autoconversion rate from application of Köhler theory. Simulations suggest that application of Köhler theory introduces a 10-20% uncertainty in global average indirec...

In this paper we present a parameterization of the nitric acid effect on cloud droplet formation. The new parameterization is intended to be used in large scale models in order to obtain regional and global estimates of the effect of nitric acid on cloud drop concentrations and the radiative balance. The parameterization is based on numerical 5 air parcel model simulations and can be applied fo...

Vertical velocity characteristics of the optically clear convective boundary layer (CBL) are examined by means of profiling airborne radar data collected in the central Great Plains during the International H2O Project, May–June 2002 (IHOP 2002). Clear-air echoes are sufficiently strong for the radar, a 95-GHz cloud radar, to detect most of the CBL at a resolution of 30 m. Vertical radar transe...

A new bulk model of the convective boundary layer, the probabilistic bulk convection model (PBCM), is presented. Unlike prior bulk approaches that have modeled the mixed-layer-top buoyancy flux as a constant fraction of the surface buoyancy flux, PBCM implements a newmixed-layer-top entrainment closure based on the mass flux of updrafts overshooting the inversion. This mass flux is related to t...

An air parcel model including homogeneous freezing nucleation of ice crystals has been used to study the formation and development of cirrus clouds. In situ measurements taken during March 1994 over southern Germany were used for comparison with model predictions. Typical experimental data were chosen for a basecase model run. Using measured aerosol properties as input values, the model predict...

To gain a deeper understanding of the structural and evolutionary characteristics supercell tornadoes that occurred in eastern China on 14 May 2021, observations from S-band dual-polarization radars, soundings other instruments are used to investigate process tornado formation by mergering strengthening storms. The results described as follows. updraft upper divergence vertical thermal instabil...

Abstract. The buoyant rise and the resultant vertical distribution of wildfire smoke in atmosphere have a strong influence on downwind pollutant concentrations at surface. amount injected vs. height is key input into chemical transport models modelling frameworks. Due to scarcity model evaluation data as well inherent complexity plume dynamics, injection predictions large uncertainties. In this...