Confronting the Challenge of Modeling Cloud and Precipitation Microphysics.

In the atmosphere, refers to the microscale processes that affect cloud and precipitation particles and is a key linkage among the various components of Earth's atmospheric water and energy cycles. The representation of microphysical processes in models continues to pose a major challenge leading to uncertainty in numerical weather forecasts and climate simulations. In this paper, the problem of treating microphysics in models is divided into two parts: (i) how to represent the population of cloud and precipitation particles, given the impossibility of simulating all particles individually within a cloud, and (ii) uncertainties in the microphysical process rates owing to fundamental gaps in knowledge of cloud physics.

Aerosol-Cloud-Precipitation Interactions in the Context of Convective Self-Aggregation.

We investigate the sensitivity of self-aggregated radiative-convective-equilibrium cloud-resolving model simulations to the cloud condensation nuclei (CCN) concentration. Experiments were conducted on a long (2,000-km × 120-km) channel domain, allowing the emergence of multiple convective clusters and dry regions of subsidence. Increasing the CCN concentration leads to increased moisture in the dry regions, increased midlevel and upper level clouds, decreased radiative cooling, and decreased precipitation.

Classical nucleation theory of homogeneous freezing of water: thermodynamic and kinetic parameters.

The probability of homogeneous ice nucleation under a set of ambient conditions can be described by nucleation rates using the theoretical framework of Classical Nucleation Theory (CNT). This framework consists of kinetic and thermodynamic parameters, of which three are not well-defined (namely the interfacial tension between ice and water, the activation energy and the prefactor), so that any CNT-based parameterization of homogeneous ice formation is less well-constrained than desired for modeling applications. Different approaches to estimate the thermodynamic and kinetic parameters of CNT are reviewed in this paper and the sensitivity of the calculated nucleation rate to the choice of parameters is investigated.

Clarifying the dominant sources and mechanisms of cirrus cloud formation.

Formation of cirrus clouds depends on the availability of ice nuclei to begin condensation of atmospheric water vapor. Although it is known that only a small fraction of atmospheric aerosols are efficient ice nuclei, the critical ingredients that make those aerosols so effective have not been established. We have determined in situ the composition of the residual particles within cirrus crystals after the ice was sublimated.

[Short- and long-term results of tuberculosis therapy with a fixed combination of isoniazide, prothionamide and diaminodiphenylsulfone combined with rifampicin].

This is a report on 912 patients treated during 1973 to 1979 for pulmonary tuberculosis and/or extrapulmonary organ involvement. These patients had been treated with a fixed tablet combination of isoniacide, prothionamide and diaphenyl sulfone in association with rifampicin and partly other substances. It was the aim of our study to examine this form of therapy in respect of side effects and effectivity.