Changes in aerosol parameters during major dust storm events (2001–2005) over the Indo‐Gangetic Plains using AERONET and MODIS data

Abstract

[1] The Indo-Gangetic (IG) plains is one of the largest and most densely populated regions in the world. Recent studies over the IG plains using multi-year (2000)(2001)(2002)(2003)(2004) satellite (including Moderate Resolution Imaging Spectroradiometer: MODIS) and ground Aerosol Robotic Network (AERONET) data show strong seasonal variability of aerosol optical depth (AOD) with maximum aerosol loading (>0.6-0.7 at 500 nm) during the pre-monsoon (summer) season. A number of major dust storms, originating from western arid and desert regions of Africa, Arabia and western part of India (Thar Desert), affect the whole IG plains during the pre-monsoon season (April-June). The mean AOD increases from 0.4-0.5 to more than 0.6-0.7 throughout the plains (>0.8-0.9 on the western side) as a result of the dust storm events. Pronounced changes in the aerosol optical parameters, derived from AERONET, have been observed over Kanpur (26.45°N, 80.35°E) during dust storm events (2001)(2002)(2003)(2004)(2005). The maximum AOD (at 500 nm) during dust event days show increase from $1 to $2.4 with advance of the pre-monsoon season (April-June). The aerosol size distribution (ASD) shows increase in radius from 1.71 to 2.24 mm (in coarse fraction) and decrease in the distribution width from 3.76 to 2.56 mm showing changes in the aerosol characteristics during dust events. The aerosol parameters [ASD, single scattering albedo (SSA, total and coarse mode) and real and imaginary parts of the refractive index] change significantly during dust events. The National Oceanic and Atmospheric Administration (NOAA) Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model (5-day back-trajectory) and MODIS level-3 daily data (AOD and Å ngström exponent) have been used to trace the source, path and spatial extent of dust storm events. During major dust events, enhancement of the total column water vapor is observed from MODIS level-3 daily water vapor data (near-infrared clear column) showing a strong association (72% correlation) with the AOD along the track of dust storms over the IG plains. A significant rise of 50-100% is observed in the ground level respirable suspended particulate matter (RSPM) concentration showing alarming health risks to the people living in the IG plains during dust storm events.Citation: Prasad, A. K., and R. P. Singh (2007), Changes in aerosol parameters during major dust storm events (2001 -2005) over the Indo-Gangetic Plains using AERONET and MODIS data,

Aerosol's optical and physical characteristics and direct radiative forcing during a shamal dust storm, a case study

“…The scattering coefficient was measured using an integrated nephelometer and absorption coefficient was measured using a multiangle absorption photometer. Moreover, similar high values of single scattering albedo has also been reported in literature under high dust loading (Li et al, 2004;Mallet et al, 2009;Prasad et al, 2007;Markowicz et al, 2008). The asymmetry parameter g is assigned a standard value of 0.73, which is most commonly used for mineral dust (Sokolik and Toon, 1999;Quijano et al, 2000;Haywood et al, 2011;Andrews et al, 2006).…”

“…A lot of ground-based and airborne measurement campaigns mainly in the African, Mediterranean and Asian regions have been conducted in recent years to analyze the optical and physical properties of dust aerosols (Sabbah et al, 2001;Ahn et al, 2007;Heinold et al, 2008;Kaskaoutis et al, 2008;McConnell et al, 2008;Osborne et al, 2008;Ansmann et al, 2011;Haywood et al, 2011), the frequency of dust outbreaks (Goudie and Middleton, 1992;Gao et al, 2003;Kutiel andFruman 2003, Rezazadeh et al, 2013) and their sources and transport range (Youlin et al, 2002;El-Askary et al, 2003, Washington et al, 2003Xuana et al, 2004;Tsolmon et al, 2008;Rashki et al, 2012;Notaro et al, 2013). Several case studies of dust outbreaks have been conducted in which direct radiative forcing at the surface and at top of the atmosphere (TOA) have been calculated using ground-based and satellite-based data (Xu et al, 2003;Costa et al, 2006;Prasad et al, 2007;Di Sarra et al, 2008;Markowicz et al, 2008;Pandithurai et al, 2008;Di Biagio et al, 2010;Lemaître et al, 2010;Park et al, 2010;Sharma et al, 2012). The results are highly variable depending on their regional and temporal scales.…”

Observed characteristics of dust storm events over the western United States using meteorological, satellite, and air quality measurements

“…Indeed, a series of studies using different observations has been done to examine the particular characteristics of dust storms (Prasad and Singh et al, 2007;Hahnenberger and Nicoll, 2012). For instance, the characteristics of dust storm events have previously been examined using stationary aerosol concentration data from the IMPROVE network (Bell et al, 2007;Tong et al, 2012).…”

Contrasting aerosol characteristics and radiative forcing over Hyderabad, India due to seasonal mesoscale and synoptic‐scale processes

“…Pre-monsoon and early monsoon are the favourable seasons for dust transport exposure from Arabia, Iran, Pakistan and northwestern India (e.g. Badarinath et al, 2007a;Prasad and Singh, 2007), enriching the atmosphere with coarse-mode aerosols and flattening the AOD spectral dependence. In addition, during the monsoon the α values are being mediated by the higher ambient RH, possible cloud contamination and long-range transport of marine air mixed with dust aerosols in certain circumstances.…”