Single scattering albedo of aerosols over the central India: Implications for the regional aerosol radiative forcing

Abstract

[1] Extensive measurements of various aerosol parameters including single scattering albedo (SSA) were made at various locations over the central Indian region during February 2004 to study their impact on the regional aerosol radiative forcing. An overall increase in the measured value of SSA is noticed (0.75 to 0.9) over the period of this campaign, indicating unequal changes in source strength or removal processes of absorbing and scattering types of aerosols. Diurnally averaged value of direct SW radiative forcing for the region is in the range of À15 to À40 W/m 2 at the surface, about 15% lower compared to that over the Bay of Bengal region and 22% higher than over the Arabian Sea. TOA forcing is in the range of +0.7 to À11 W/m 2 , about 50% lower compared to both these regions. This results in a heating rate of nearly 0.8 K/day for the first 2km in the atmosphere. Citation: Ganguly, D., H. Gadhavi, A. Jayaraman, T. A. Rajesh, and A. Misra (2005), Single scattering albedo of aerosols over the central India: Implications for the regional aerosol radiative forcing, Geophys.

Truncation and Angular-Scattering Corrections for Absorbing Aerosol in the TSI 3563 Nephelometer

“…Measured SSA ranges from 0.88 in polluted continental outflow to nearly 1 in clean marine air (Quinn and Bates 2005). Closer to source regions, SSA varies from 0.73 to 0.82 (Ganguly et al 2005;Garland et al 2008). …”

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

“…The atmospheric heating is controlled by the aerosol load and absorbing capability of aerosols and is ∼55 W m −2 in the period January to April, except for the higher value (70 W m −2 ) in March. The enhanced presence of BC aerosols in winter, associated with the lower boundary-layer height and the absence of precipitation, plays an important role in the large atmospheric forcing values also found over continental India (Ganguly et al, 2005b). In contrast, in the monsoon and post-monsoon the atmospheric forcing is much lower.…”

“…During April-September, SSA is found to be higher (> ∼ 0.9) due to increased contribution of watersoluble aerosols, sea salt, mineral transported and lower soot concentrations (Table 1). The water-soluble aerosols may grow hygroscopically in size under high RH and contribute to the higher SSA values (Ganguly et al, 2005b). The seasonally averaged SSA values obtained over Hyderabad are summarized with those reported over different locations in the Indian subcontinent and adjoining oceanic regions in Table 2.…”

“…Ganguly et al, 2005a;Moorthy et al, 2009;among many others). During the road campaign (February 2004), the ARF over Hyderabad was found to be ∼−40 W m −2 at the surface and ∼−5.5 W m −2 at TOA, higher than those found over remote areas in continental India (Ganguly et al, 2005b;Jayaraman et al, 2006). Regionally averaged net ARF over the Bay of Bengal was in the range of −15 to −24 W m −2 at the surface and −2 to −4 W m −2 at TOA during February 2003 (Vinoj et al, 2004).…”

Airborne lidar study of the vertical distribution of aerosols over Hyderabad, an urban site in central India, and its implication for radiative forcing calculations

“…First, the normalized relative backscatter (NRB) profile is obtained by correcting for afterpulse effect, overlap correction, energy normalization, range correction etc. as described in Campbell et al (2002) and Gadhavi (2005). The second step is to calculate extinction profile from NRB, which is described in Sect.…”