Smoke aerosol and its radiative effects during extreme fire event over Central Russia in summer 2010статья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
Аннотация:Different microphysical, optical and radiative
properties of aerosol were analyzed during the severe fires
in summer 2010 over Central Russia using ground measurements
at two AERONET sites in Moscow (Meteorological
Observatory of Moscow State University – MSU MO)
and Zvenigorod (Moscow Region) and radiative measurements
at the MSU MO. Volume aerosol size distribution in
smoke conditions had a bimodal character with the signifi-
cant prevalence of fine mode particles, for which effective radius
was shifted to higher values (reff−fine =0.24 µm against
approximately 0.15 µm in typical conditions). For smoke
aerosol, the imaginary part of refractive index (REFI) in the
visible spectral region was lower than that for typical aerosol
(REFI=675 nm =0.006 against REFI=675 nm =0.01), while
single scattering albedo (SSA) was significantly higher
(SSA=675 nm =0.95 against SSA=675 nm 0.9). Extremely
high aerosol optical thickness at 500 nm (AOT500) was observed
on 6–8 August reaching the absolute maximum on
7 August in Moscow (AOT500=6.4) and at Zvenigorod
(AOT500=5.9). A dramatic attenuation of solar irradiance
at ground was also recorded. Maximum irradiance loss had
reached 64% for global shortwave irradiance, 91% for UV
radiation 300–380 nm, and 97% for erythemally-weighted
UV irradiance at relatively high solar elevation 47. Signifi-
cant spectral dependence in attenuation of solar irradiance in
smoky conditions was mainly explained by higher AOT and
smaller SSA in UV (0.8–0.9) compared with SSA in the visible
region of spectrum. The assessments of radiative forcing
effect (RFE) at the TOA indicated a significant cooling of
the smoky atmosphere. Instant RFE reached −167Wm−2 at
AOT500=6.4, climatological RFE calculated with August
2010 monthly mean AOT was about −65Wm−2, compared
with −20Wm−2 for typical aerosol according to the 10 yr
period of measurements in Moscow.