نتایج جستجو برای: dust events

تعداد نتایج: 362026  

2006
I. Tegen B. Heinold M. Todd J. Helmert R. Washington O. Dubovik

We present regional model simulations of the dust emission events during the Bodélé Dust Experiment (BoDEx) that was carried out in February and March 2005 in Chad. A box model version of the dust emission model is used to test different input parameters for the emission model, and to compare the dust emissions computed with observed wind speeds to those calculated with wind speeds from the reg...

2011
L. Klüser D. Martynenko

From the high spectral resolution thermal infrared observations of the Infrared Atmospheric Sounding Interferometer (IASI) mineral dust AOD (transferred from thermal infrared to 0.5 μm) is retrieved using a Singular Vector Decomposition of brightness temperature spectra. As infrared retrieval based on 8–12 μm observations, dust observation with IASI is independent from solar illumination. Throu...

2004
M. C. Towner T. J. Ringrose M. R. Patel M. Balme S. M. Metzger R. Greeley J. C. Zarnecki

Introduction: During August 03 a dust devil field investigation campaign was conducted in the El Dorado Valley, Nevada. This field site has been well characterised previously [9], and has a well documented record of dust devil events. We report on one particular encounter from this field campaign, whereby a dust devil was sampled by a large number of sensors. These measurements consist of wind ...

2008
Jeffrey Mendez Cecile Guieu Jess Adkins

Dissolution of wind blown dust is a major source of iron, manganese, and other trace nutrients in the ocean. Kinetic and thermodynamic values for the release of metals from dust are needed for computer models which incorporate dust as part of their ocean system. Here we investigate both the thermodynamic and kinetics parameters involved in the dissolution of metals from dust in seawater. We add...

2004
Jun Wang Xiangao Xia Pucai Wang Sundar A. Christopher

[1] Using 22 months of Sunphotometer Aerosol Optical Thickness (AOT) data collected near the Taklamakan and Gobi dust source regions (Dunhuang, 40.09 N, 94.41 E) in China; we examine the diurnal and seasonal change of dust aerosol properties. Most dust events are during the spring through early summer months with a season-invariant diurnal change of more than ±10% for AOTand ±30% for Angström e...

2006
Claire E. Newman Stephen R. Lewis

Multi-annual dust transport simulations have been performed using a Mars general circulation model containing a dust transport scheme which responds to changes in the atmospheric state. If the dust transport is ‘radiatively active’ the atmospheric state also responds to changes in the dust distribution. This paper examines the suspended dust distribution obtained using different lifting paramet...

Extended abstract Introduction Dust storms are natural hazards that effect on weather conditions, human health and ecosystem. Atmospheric processes are directly affected by the absorption and diffusion of radiation by dust, and dust in the cloud acts as a nucleus of congestion. The main dust areas in the world are flat topographically dry areas with erosion-sensitive soil and poor vege...

Journal: :محیط شناسی 0
ام السلمه بابایی فینی استادیار اقلیم شناسی، گروه جغرافیا، دانشگاه پیام نور طاهر صفرراد دانشجوی دکتری اقلیم شناسی، دانشکدۀ جغرافیا، دانشگاه تهران مصطفی کریمی استادیار اقلیم شناسی، دانشکدۀ جغرافیا، دانشگاه تهران

introduction earth has ever been exposed to environmental hazards. the hazards are continually occurring in the world in the recent years. among them, atmospheric elements have created many human and financial losses in different regions. one of the hazards is dust events and in its severe case is dust storm. it happens more frequently in arid and semiarid regions in deserts and their surroundi...

2015
Kjartan M Kinch James F Bell Walter Goetz Jeffrey R Johnson Jonathan Joseph Morten Bo Madsen Jascha Sohl-Dickstein

The Panoramic Cameras on NASA's Mars Exploration Rovers have each returned more than 17,000 images of their calibration targets. In order to make optimal use of this data set for reflectance calibration, a correction must be made for the presence of air fall dust. Here we present an improved dust correction procedure based on a two-layer scattering model, and we present a dust reflectance spect...

2004
M. Collaud Coen U. Baltensperger

Scattering and absorption coefficients have been measured continuously at several wavelengths since March 2001 at the high altitude site Jungfraujoch (3580 m a.s.l.). From these data, the wavelength dependences of the Ångström exponent and particularly of the single scattering albedo are determined. While the exponent of the single scattering albedo usually increases with wavelength, it decreas...

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