Light absorption by carbonaceous aerosol and dust in the high Himalayas and Tibetan Plateau

The plateau-scale variations of aerosol components and the light absorption by organic carbon (OC), elemental carbon (EC), and dust determine their impacts on the hydrological cycle and climate warming over the high Himalayas and Tibetan Plateau (the HTP). The simultaneous in-situ measurements of these components and light absorption are lacking attributed to the extremely harsh environments, and thus there exist large difficulties to distinguish the contributions of the three components to light absorption. In this study, the major light-absorbing materials and corresponding multiwavelength absorption were combined to obtain the specified contributions. The spatial variations of total suspended particle (TSP) mass were observed across the HTP, with large contributions from dust, carbon components, and SNA (including sulfate, nitrate, and ammonium). Enhanced primary and secondary OC, and SNA in the margin area of the HTPwere consistent with high OX (O3+NO2), relative humidity (RH), and intensive anthropogenic activities. The major light-absorbing was attributed to EC with percentages of 68%, 46%, and 64% in Ngari, Qinghai lake, and Beiluhe, respectively. Enhanced light-absorbing contributions of carbonaceous aerosol were obtained in the margin area, especially in the heating seasons (~90%), which indicated the important effects of anthropogenic emissions in the HTP. Fugitive dust was an important contributor to TSP mass, while not for light absorption. The concurrent constraints on the mass and optical properties of OC, EC, and dust in the present study can provide an opportunity to narrow the climate model uncertainties in the HTP.