Dust Induced Changes in Ice Cloud and Cloud Radiative Forcing over a High Altitude Site

Abstract

Aerosol-cloud interaction is the subject of considerable scientific research, due to the importance of clouds in controlling climate. In the present study, three years (2011)(2012)(2013) satellite observations are used to investigate the aerosol indirect effect (AIE) over Dehradun. The low values of Angstrom exponent (α) during March-July are attributed to the loading of dust-like coarse particles in the atmosphere, whereas the analysis of aerosol type and Spectral Radiation Transport Model for Aerosol species (SPRINTARS) simulated aerosol species variation supports the fact. Moderate Resolution Imaging Spectroradiometer (MODIS) derived AOD data are associated to the cloud product to examine the dust impact on properties of liquid cloud and ice cloud. The positive values of aerosol cloud interaction effect (ACI) for ice cloud during pre-monsoon (March-May) and monsoon (June-August) seasons reveal the significant impact of dust on ice clouds over Dehradun, which is maximum during May (~0.24 ± 0.05). The present study shows that ice cloud effective radius (ICER) decrease with AOD during dust period. The increase in ice water path (IWP) and ice cloud optical depth (ICOD) reveals the impact of dust on heterogeneous ice generation in low level clouds. However, there is no relation between dust and liquid water cloud during dust period. It is difficult to provide definite conclusions that the dust and cloud changes are driven by the same meteorological conditions. Cloud and the Earth's Radiant Energy System (CERES) derived flux data are used to examine the associated changes in TOA cloud radiative forcing. The diminution in effective size of ice crystal due to aerosol first indirect effect traps more longwave radiation and reflects more solar radiation. Both first and second indirect effects enhance cloud cooling, whereas the dust induced cloud warming is mainly the result of the semi-direct effect.

Type‐Dependent Responses of Ice Cloud Properties to Aerosols From Satellite Retrievals

“…However, the aerosol effects on ice clouds have been difficult to constrain due to numerous controlling factors. For example, Huang et al (2006) and W. C. showed that the existence of dust aerosols significantly lower cloud optical thickness (COT) and ice water path (IWP) of ice clouds compared with pristine conditions, whereas a number of studies (Ou et al, 2009;Patel & Kumar, 2016;Tesche et al, 2016) reported a significant increase in COT and/or IWP with an increase in dust aerosols or aircraft exhaust. C. Wang et al, 2015).…”

“…However, the aerosol effects on ice clouds have been difficult to constrain due to numerous controlling factors. Moreover, limited available studies have shown contradicting results (Chylek et al, 2006;Huang et al, 2006;Jiang et al, 2008;Ou et al, 2009;Patel & Kumar, 2016;Su et al, 2011;Tesche et al, 2016;W. C. Wang et al, 2015).…”

“…C. Wang et al, 2015). For example, Huang et al (2006) and W. C. showed that the existence of dust aerosols significantly lower cloud optical thickness (COT) and ice water path (IWP) of ice clouds compared with pristine conditions, whereas a number of studies (Ou et al, 2009;Patel & Kumar, 2016;Tesche et al, 2016) reported a significant increase in COT and/or IWP with an increase in dust aerosols or aircraft exhaust. While the causes for the disagreement and uncertainty are not yet clear, the distinct characteristics of different ice cloud and aerosol types under various meteorological conditions could presumably lead to different aerosol-ice cloud relationships.…”

Resolving Vertical Profile of Cloud Condensation Nuclei Concentrations from Spaceborne Lidar Measurements

“…ACI studies often use satellite retrievals to take advantage of their global coverage, but satellites have been unable to measure the CCN. Nevertheless, the aerosol optical parameters such as aerosol optical depth (AOD) and aerosol index (AI) are commonly used as proxies for CCN in previous studies (Gryspeerdt & Stier, 2012;Patel et al, 2017Patel et al, , 2019Patel & Kumar, 2016;Quaas et al, 2008Quaas et al, , 2009Rosenfeld, 2008). However, all these proxies are crude tools and suffer from various issues such as aerosol swelling, lack of vertical information, cloud contamination, uncertainty in size distribution and solubility, and more (Rosenfeld et al, 2016).…”

Strengthened Indian Summer Monsoon Precipitation Susceptibility Linked to Dust‐Induced Ice Cloud Modification

“…In the south Asian context, field observations conducted near the Himalayan foothills in India indicated the presence of elevated transported dust (Padmakumari et al, 2013) and large spatial variation in IN concentrations (Patade et al, 2014). Dust-induced microphysical responses in ice cloud formation have been studied over India using general circulation models (GCMs; Hazra, 2013) and satellite observations (Patel & Kumar, 2016). However, the response of precipitation to dust-induced ice cloud modification and its meteorological dependency is largely unknown.…”