182
N. F. Elansky
2013b; Bazhenov, 2014]. These ozone anomalies were accompanied by a decrease
in the
stratospheric content of NO
2
. At the ZSS, in late March 2011, the content
of NO
2
decreased by 40% with respect to its mean value for this time of the year
[
Gruzdev and Elokhov, 2012; Gruzdev and Elokhov, 2013]. Record negative NO
2
anomalies (30% decrease) were observed during the 2011 winter–spring period
in Tomsk and Zhigansk [
Ageyeva et al., 2014]. In all cases, a rapid decrease in the
TOC and NO2 was accompanied by a decrease in air temperature and in the
heights of isobaric surfaces in the stratosphere [
Bazhenov, 2011; Bazhenov, 2012].
A close relation between ozone and NO2 in the atmosphere is also manifest‑
ed in the response of the latter to variations in solar activity and atmospheric
circulation. A unique 30-year data series on the NO2 content in the entire atmos‑
pheric vertical column, which was obtained from direct solar-radiation measure‑
ments at the KHASS station from 1979 to 2008, is given in [
Arabov et al., 2012].
Its analysis revealed the characteristic features of the time variability of the total
content of NO
2
, which are associated with the 11-year solar-activity cycle, vol‑
canic eruptions, quasi‑biennial oscillations of tropical
circulation, and the El
Nino effect. These features quantitatively differ from those revealed from meas‑
urements of the stratospheric content of NO2 according to solar radiation scat‑
tered in the zenith (NDAAC data).
TOC variations exceeding 100 DU may occur during a day. Such situations
were analyzed on the basis of observational data obtained in 2009
[Ivanova,
2011] and 2009–2011 [
Ivanova, 2013]. It was shown that a rapid increase (de‑
crease) in the TOC is unambiguously associated with a descent (ascent) of the
tropopause position. The recurrence of such situations throughout the year
amounts to 0.25–0.27% of the total sample. Some of such situations were noted
to be related to a sudden stratospheric warming.
2.2. Vertical ozone distribution
Over the past four years, the system for monitoring the vertical ozone distri‑
bution (VOD), on the whole, has remained unchanged. Ozonesondes were occa‑
sionally launched mainly in winter [
Dorokhov et al., 2013; Dorokhov et al.,
2014]. Both microwave (Moscow and Nizhny Novgorod) and lidar (Tomsk)
soundings were continuously carried out. Instruments and methods for sounding
were significantly improved. A new-generation mobile automated microwave
spectroradiometer was developed. This instrument makes it possible to obtain
data on the VOD within a height range of 20–60 km during 15–20 min. A more
accurate algorithm for retrieving vertical profiles was also developed. This algo‑
rithm combines the Tikhonov regularization method and the method of statistical
regularization [
Solomonov et al., 2011]. A multiyear data series on the VOD over