Characterization of aerosol optical properties over the high-altitude station Hanle, in the trans-Himalayan region

Spring-Time Enhancement in Aerosol Burden over a High-Altitude Location in Western Trans-Himalaya:Results from Long-Term Observations

“…This observatory is also a part of the network of observatories under Aerosol Radiative Forcing over India (ARFI) project of ISRO-GBP, which is now known as ARFINET 23,24 . Some of the findings from this observatory have been published earlier [25][26][27][28][29][30][31] . These include the role of photochemistry in the new particle formation events at the freetropospheric altitudes 25 , temporal evolution and annual cycle in BC concentration over the Himalaya 26 , dust transport and associated changes in physical and optical properties of aerosols [27][28][29][30][31] and spring-time enhancement in aerosol optical depth (AOD) and BC over Hanle 30 .…”

“…Some of the findings from this observatory have been published earlier [25][26][27][28][29][30][31] . These include the role of photochemistry in the new particle formation events at the freetropospheric altitudes 25 , temporal evolution and annual cycle in BC concentration over the Himalaya 26 , dust transport and associated changes in physical and optical properties of aerosols [27][28][29][30][31] and spring-time enhancement in aerosol optical depth (AOD) and BC over Hanle 30 . While these earlier works are focused on characterization of aerosol optical and physical properties over Hanle, this article presents the quantitative estimation of spring-time enhancement in aerosol loading, its vertical structure and possible reasons for the inter-annual variability in springtime enhancement based on long-term observations of aerosol properties over Hanle during August 2009-December 2014.…”

“…Saraswati), among which some are snow-covered throughout the year while others experience seasonal precipitation, especially during winter (December-February) and summer (JulyAugust). More details of this near-free-tropospheric background location are available in the literature [25][26][27][28][29][30][31] . Figure 2 shows the prevailing surface meteorological conditions obtained using data from a collocated automatic weather station.…”

“…We have examined this further, using the spectral Angstrom exponent (), which revealed clear seasonal transition in aerosol types with higher  (~1.2) in autumn indicating fine particle contribution, and lower  in spring (~0.34) suggesting the dominance of coarsemode particles, which indicate the role of transported dust. Ningombam et al 28 analysed CALIOP (the CloudAerosol Lidar with Orthogonal Polarization)-derived aerosol vertical profiles along with back trajectories superimposed with the MODIS fire count data and suggested that the episodes having high AOD and low  (mostly during spring season) were associated with the presence of desert dust at altitudes of 5-7 km amsl. The airmass trajectories during such periods mostly arrived from longer distances with relatively higher altitudes and passed over different desert regions.…”

An Evaluation of the CHIMERE Chemistry Transport Model to Simulate Dust Outbreaks across the Northern Hemisphere in March 2014

“…In this region, a specific work described in a recent study [126] analyzed the impact of a change in horizontal distribution of emissions that lead to better simulations of dust storms with the WRF-chem model. Several studies focusing over India and Nepal agree to show the significant influence of long-range transport of dust from western desert regions, such as North Africa and the Arabic Peninsula in February-March due to changes in meteorological condition related to the starting of the Monsoon Season [127][128][129].…”