An empirical equation to estimate mineral dust concentrations from visibility observations in Northern Africa

作者：Camino C^*; Cuevas E; Basart S; Alonso Perez S; Baldasano J M; Terradellas E; Marticorena B; Rodriguez S; Berjon A

来源：Aeolian Research, 2015, 16: 55-68.

DOI：10.1016/j.aeolia.2014.11.002

• PM10
• Visibility
• Mineral dust
• Dust transport model
• MODIS-AQUA

This paper presents a new empirical equation relating horizontal visibility and PM10 dust concentrations. The new empirical equation (IZO-Eq) is derived from observations performed at the Izana Atmospheric Observatory (IZO, 28.30 degrees N, 16.49 degrees W, 2367 m a.s.l., Tenerife, Spain), recorded during Saharan dust outbreaks from 2003 to 2010. A filter based on relative humidity, present-weather and aerosol optical properties is applied to identify dust events. IZO-Eq is validated in the Sahel region during the dry and wet seasons (2006-2008) using data from two PM10 monitoring stations from the African Monsoon Multidisciplinary Analysis (AMMA) International Project, and data from the nearest meteorological synoptic stations. The estimated PM10, derived from IZO-Eq is compared against that those obtained by other empirical equations and dust surface concentrations from NMMB/BSC-Dust model. IZO-Eq presents better performance than the other equations in both dry and wet seasons when compared with observed PM10 at two Sahelian sites. IZO-Eq is also able to reproduce the surface concentration variability simulated by NMMB/BSC-Dust. Above 10 km of horizontal visibility, empirical equations cannot be used to estimate PM10, since above this threshold equations estimate a nearly constant PM10 value, regardless of the visibility range. A comparison between the PM10 spatial distributions derived from visibility SYNOP observations through IZO-Eq, the modelled values from the NMMB/BSC-Dust model and aerosol optical depth (AOD) retrieved from MODIS is performed for the 2006-2008 period. The different spatial distributions present a rather good agreement among them as well as to reproduce the characteristic seasonal dust features over North Africa.

• 出版日期2015-3