Estimates for the sedimentation rate of realistic ice crystals at sizes smaller than 100 μm are presented. These calculations, which exploit new results for the capacitance of ice crystals, are compared with laboratory studies and found to be in good agreement. The results highlight a weakness in contemporary ice particle fall speed parameterisations for very small crystals, which can lead to s...

We investigate the limitation of using the asymmetry factor through the Henyey-Greenstein function in representing the scattering phase function for radiative transfer in ice clouds containing hexagonal ice crystals. Relative accuracy checks for solar fluxes are carried out using three cirrus cloud size distributions. The flux results computed from the Henyey-Greenstein phase function, based on...

A silver iodide (AgI) cloud-seeding parameterization has been implemented into the Thompson microphysics scheme of the Weather Research and Forecasting model to investigate glaciogenic cloudseeding effects. The sensitivity of the parameterization to meteorological conditions, cloud properties, and seeding rates was examined by simulating two-dimensional idealized moist flow over a bell-shaped m...

Marine organisms must possess strategies enabling them to initiate calcite precipitation despite the unfavorable conditions for inorganic precipitation in surface seawater. These strategies are poorly understood. Here we compare two potential strategies of marine calcifyers to manipulate seawater chemistry in order to initiate calcite precipitation: Removal of Mg and H ions from seawater soluti...

In this paper, a novel method for rain rate estimation is researched by polarimetric phase shift of the Global Navigation Satellite System (GNSS). The physical process of GNSS signals propagating through rain-filled medium is investigated, by which the cause of polarimetric phase shift is explored. Then, a theoretical model between polarimetric phase shift ∆φ and rain rate R is established and ...

Phase relations between climate variables are critical in order to ascertain the main mechanisms driving glaciation cycles. Proxy records from ice cores are commonly assumed to represent annual mean averages. These averages, however, may be biased toward a particular season due, for example, to a change in the distribution of precipitation. We demonstrate using a nine-box model of the climate s...

Concentrations of inorganic ions (Cl , H + , SO4 2, NO3 , NH4 + , Na + , K + , Ca 2+ , Mg 2+ ) and metals (V, Ni, Cu, Pb, Cr Mn, Al, Fe) in bulk precipitation and PM10 samples collected in the metropolitan area of Costa Rica were analyzed. Good correlations between acidity in bulk precipitation with the concentrations of aerosols in the air were observed. The scavenging of the pollutants from t...

1. Whewellite (calcium oxalate monohydrate) crystals were found to induce epitaxially the heterogeneous nucleation of brushite (calcium monohydrogen phosphate dihydrate) from its metastable supersaturated solution in approximately one-quarter of the time required for spontaneous precipitation in the absence of added nucleating agents. Scanning electron-microscope observation of the crystalline ...

Small water ice crystals are the main component of cold tropospheric clouds such as cirrus. Because these clouds cover large areas of our planet, their role in the radiation budget of incoming and outgoing radiation to the planet’s surface is important. At present, the representation of these clouds in climate and weather models is subject to improvements: a large part of the uncertainty error ...

Winter storms in California's Sierra Nevada increase seasonal snowpack and provide critical water resources and hydropower for the state. Thus, the mechanisms influencing precipitation in this region have been the subject of research for decades. Previous studies suggest Asian dust enhances cloud ice and precipitation, whereas few studies consider biological aerosols as an important global sour...