iran is facing dust storms every year and frequently. this phenomenon has affected, especially in recent years, various aspects of people's lives. the aim of this research is iran’s seasonal clustering in terms of dust storms frequency with visibility less than 1000 and 500 m for the period of 1987–2008. for this purpose, we used the data of 87 synoptic stations that had suitable spatial d...

The presence of the two distinct groups of ultracool dwarfs (UCDs), ‘L’ and ‘T’ types, is now well established: L dwarfs are thought to be dusty while T dwarfs show strong bands of methane (CH4) but little evidence for dust in their spectra. So far, different model sequences, which we referred to as the dusty model (or case B) and dustsegregated model (or case C) have been considered for L and ...

1- introduction despite of technology progressives, natural hazards caused damage of world cities propertys and life, part of the damages related to adequate uncognition response to natural hazards. the dust natural hazard occurrence has attracted public attention in the recent years. nonrecieption and attention to the natural hazards not only affected society economic, but also affected differ...

Abstract. Mineral dust and sea spray aerosol represent important sources of ice-nucleating particles (INPs), the minor fraction able to trigger cloud ice crystal formation and, consequently, influence multiple climate-relevant properties including lifetime, radiative precipitation initiation efficiency. is considered dominant INP source in many parts world due its nucleation efficiency sheer ab...

The presence of the two distinct groups of ultracool dwarfs (UCDs), ‘L’ and ‘T’ types, is now well established: L dwarfs are thought to be dusty while T dwarfs show strong bands of methane (CH4) but little evidence for dust in their spectra. So far, different model sequences, which we referred to as the dusty model (or case B) and dustsegregated model (or case C) have been considered for L and ...

Fifty-one dense cores associated with water masers were mapped at 350 μm. These cores are very luminous, 10 < Lbol/L⊙ < 10 , indicative of the formation of massive stars. Dust continuum contour maps, radial intensity profiles, and photometry are presented for these sources. The submillimeter dust emission peak is, on average, nearly coincident with the water maser position. The spectral energy ...

Context. Recent observations of brown dwarf spectroscopic variability in the infrared infer the presence of patchy cloud cover. Aims. This paper proposes a mechanism for producing inhomogeneous cloud coverage due to the depletion of cloud particles through the Coulomb explosion of dust in atmospheric plasma regions. Charged dust grains Coulomb-explode when the electrostatic stress of the grain ...