Eurasian Large-Scale Hazes in Summer 2016

The technique for constructing the spatial distribution of maximum aerosol optical depth (MAOD) has been used to estimate the optically dense haze expansion scales from July 15 to 31, 2016 (over an area of 20 million km²), including the record-scale Siberian smoke haze (SSH) with an area of around 16 million km², smog over the Northern China Plain (around 2 million km²) and the adjacent offshore zones, a dust haze in the Taklamakan Desert (around 0.8 million km²), and hazes in India and Pakistan (almost 1 million km²). The empirical distribution function (EDF) of the MAOD is approximated by a linear function of the MAOD logarithm. The spatial distribution of aerosol optical depth (AOD) at a wavelength of 550 nm in the SSH has been analyzed. The total mass of smoke aerosol in the SSH has been estimated to be 3.2 million t, including around 2 million t over the territory of Siberia (50–70° N, 60–120° E) during the peak haze from July 22 to July 26, 2016. The qualitative composition of smoke aerosol in the SSH during its transport is illustrated through spatial and temporal variations in the aerosol index (AI). It is shown that AI variations are correlated with AOD variations. Aerosol radiative forcings (ARFs) at the upper and lower atmospheric boundaries over Siberia from July 22 to 26, 2016, have been estimated (with an average ARF of –68 and –98 W/m²). The EDFs of AOD and ARF at the upper atmospheric boundary have been approximated by exponential and power function of AOD, respectively.