High altitude (∼4520 m amsl) measurements of black carbon aerosols over western trans‐Himalayas: Seasonal heterogeneity and source apportionment

摘要: [1] The first ever, year-round measurements of aerosol black carbon (BC) over the western part trans- Himalayas are reported from Hanle (∼4520 m above mean sea level). The daily BC concentrations varied as low 7 ng m−3 to high 296 with an annual average 77 ± 64 m−3, indicating significant burden even at free- tropospheric altitudes. Variation in day well were highly subdued during winter season (December February) while they used be highest Spring (March May). In general, less frequently occurring values contributed more and seasonal means, 64% below mean. Seasonally, concentration (109 78 m−3) occurred lowest (66 42/66 62 m3) Summer/Winter season(June August/December February). Diurnal variations general very weak, except Summer when effects convective boundary layer dynamics is discernible. Back trajectory clustering weighted (CWT) analyses indicated that, most time year sampling location influenced by advection West Southwest Asia, contribution Indo-Gangetic Plains (IGP) remained Summer. significantly lower than corresponding for other Himalayan stations, quite higher those South Pole pristine Antarctic environments.