The Black carbon (BC) and Brown carbon (BrC) concentration has been measured over Srinagar (Garhwal) in central Himalayas during October 2020 to September 2021 periods. The average BC mass was 2.59 +/- 1.96 mu g m- 3 and its absorption coefficients were abundant at shorter wavelength. BC seasonal variation exhibited a significant variability, with highest during winter (4.54 +/- 2.64 mu g m- 3) followed by pre-monsoon (2.69 +/- 2.04 mu g m- 3) and post-monsoon (1.93 +/- 0.91 mu g m- 3) while lowest was observed in the monsoon (1.05 +/- 0.54 mu g m- 3). Relatively high contribution of total spectral light absorption coefficient (Abs lambda) was observed (75.94 Mm-1) at 370 nm than longer wavelength (16.86 Mm-1) at 950 nm. The BrC contribution was higher at 370 nm (32.50 Mm-1) to the total babs (lambda), while at higher wavelengths it has extensively decreased (2.54 Mm-1 at 660 nm). Seasonally, the absorption coefficient of BC and BrC was greater in winter (83.99 and 68.37 Mm-1) while lowest in monsoon (19.38 and 9.27 Mm-1), respectively. The babs BrC/babs (t) ratio revealed higher contribution of BrC in winters. The secondary brown carbon (BrCsec) and primary brown carbon (BrCpri) contributed 43.16 % and 56.88 % towards the total BrC Abs (lambda) at 370 nm with higher in winter and lowest in monsoon, respectively. BrCsec and BrCprim has shown higher contribution in evening (18.00-20.00 h) and in morning (09.00-11.00 h) hours. The average radiative forcing (RF) of BC was 36.11 +/- 6.99 Wm-2, 2.19 +/- 1.22 Wm-2 and -33.92 +/- 5.96 Wm-2 at the atmosphere (ATM), Top of the Atmosphere (TOA), and at the Surface (SUR), respectively.

Black carbon (BC), primary brown carbon (BrCpri), and secondary brown carbon (BrCsec) are important light-absorbing aerosol. BC and BrC from the surrounding area can reach the Tibetan Plateau (TP) and influence climate change and glacial melting. Here, we presented a study of the light absorption, radiative forcing, and potential source areas of BC and BrC over the northeastern, central, and southwestern TP. The higher light absorption was observed in the northeastern and southwestern sites compared to the central TP site. The major carbonaceous light-absorbing was attributed to BC with the percentages of 65%, 56%, and 82% in Ngari, Qinghai Lake, and Beiluhe, respectively. The heighten contribution of BrCsec to total light absorption indicated the importance of BrCsec in the TP, especially in the northeastern and southwestern areas. The BrCsec radiative forcings relative to BC were much higher than those of BrCpri. The potential BC and BrCpri source distributions were obtained.