key: cord-0064861-u3zjqzor
authors: Ivanova, N. S.; Kruchenitskii, G. M.; Kuznetsova, I. N.; Shalygina, I. Yu.; Lezina, E. A.
title: Ozone Content over the Russian Federation in 2020
date: 2021-06-24
journal: Russ
DOI: 10.3103/s1068373921020084
sha: 852c2701dbfa26b0bcc25947f619dc39dc575025
doc_id: 64861
cord_uid: u3zjqzor

The review is based on the results of operation of the total ozone (TO) monitoring system in Russia and neighboring countries that functions in the operational mode at the Central Aerological Observatory. The monitoring system uses data from the national network equipped with M-124 filter ozonometers being under the methodological supervision of the Main Geophysical Observatory. The quality of the functioning of the entire system is operationally controlled using the OMI satellite equipment observations (NASA, USA). Basic TO observation data are generalized for each month of the fourth quarter of 2020, for the fourth quarter, and for the whole year. Data of routine observations of surface ozone in the Moscow region are also presented.

The basic results of total ozone (TO) observations for the first three quarters of 2020 were described before in [10] [11] [12] . The normals (multiyear means) of TO over Russia and adjoining areas computed for different months of the fourth quarter for the period of 1974-1984 were presented in [4] . The deviations from the normal are given in percent and standard deviation units; the anomalous deviation is the deviation from the normal by ³2.5 SD. The low quality of observational data from Samara, Vladivostok, Krasnoyarsk, Nikolaevsk-on-Amur, Voronezh, Karaganda, Almaty, Semipalatinsk, Arkhangelsk, Murmansk, Bol'shaya Elan', and Chardzhou stations does not allow their use for analyzing the TO field for the whole year. In addition, observational data from Khanty-Mansiysk and Gur'ev stations were not used to analyze the TO fields for the fourth quarter of 2020 for the same reason.

The quar terly mean TO val ues in the fourth quar ter of 2020 were close to the multiyear means for 1974-1984 (Fig. 1a) . The max i mum de fi ciency of quar terly mean TO val ues was reg is tered in Yakutsk and amounted to 8% or 2.0 SD. The max i mum ex ceed ing over the nor mal was reg is tered in Tomsk (8% or 2.4 SD). The low est quar terly mean TO val ues (272-310 DU) in the fourth quar ter of 2020 were ob served over the Eu ro pean part of Rus sia, over the Ural, the north ern re gions of West ern and Cen tral Si be ria, and over west ern Kazakhstan. The high est val ues (355-366 DU) were reg is tered over the Magadan oblast and Kamchatka. Over the rest of the ter ri tory un der con trol the TO val ues were 310-355 DU.

Ta ble 1 pres ents data on the anom a lous de vi a tions from the nor mal of daily TO val ues re corded at the ozonometric sta tions in the fourth quar ter of 2020.

In Oc to ber 2020 the monthly mean TO val ues were close to the nor mal over the ter ri tory un der con trol (Fig. 1b) . The max i mum de fi ciency of monthly mean TO val ues was re corded at Kotel'nyi Osland sta tion and amounted to 7% or 1.1 SD. The nor mal was max i mally ex ceeded in Tomsk: by 9% or 2.1 SD.

In No vem ber the monthly mean TO val ues were ba si cally close to the nor mal over the ter ri tory un der con trol (Fig. 1c) . The monthly mean TO val ues be low the nor mal (by 10-20%) were ob served over the north of the Krasnoyarsk krai, over Yakutia and the Magadan oblast. The anom a lous de fi ciency of monthly mean TO val ues was reg is tered in Yakutsk (20% or 2.9 SD). The max i mum ex ceed ing over the nor mal was reg is tered in Mos cow: 8% or 1.5 SD.

In De cem ber the monthly mean TO val ues were close to the nor mal over the ter ri tory un der con trol (Fig. 1d) . The quar terly mean TO val ues be low the nor mal (by 10-16%) were ob served over the northwest ern re gions of Eu ro pean Rus sia. The max i mum de fi ciency of monthly mean TO val ues was re corded in St. Pe ters burg: 16% or 2.3 SD. The max i mum ex ceed ing of the nor mal was reg is tered at Nagaevo sta tion (11% or 1.9 SD).

The de vi a tions of an nual mean TO val ues from the nor mal in 2020 (Fig. 1e ) at most sta tions in Rus sia are neg a tive and are in the range from -14 to 3% for all an a lyzed sta tions. The larg est de vi a tions were reg istered on the Arc tic Ocean is lands, in the north of the Krasnoyarsk krai and Yakutia, which was an ef fect of the large and du ra ble ozone anom aly in the win ter-spring pe riod [11, 12] . The max i mum de fi ciency of an -130 IVANOVA et al. nual TO means (14%) was reg is tered at Tura, Olenek, and Kotel'nyi Is land sta tions. The max i mum ex ceeding of an nual mean TO val ues over the nor mal (3%) was ob served in Tsimlyansk. Dur ing 2020, some con sid er able de vi a tions of daily TO val ues from the nor mal were reg is tered in Jan uary-May. For ex am ple, the daily TO val ues were be low the nor mal:

-by 35-46% on Jan u ary 27-29 over the north ern re gions of Eu ro pean Rus sia (190-232 DU); -by 30-45% on Feb ru ary 5-6 over the north ern re gions of the Krasnoyarsk krai and Evenkia (238-322 DU); -by 28-43% on Feb ru ary 9-10 over the north ern re gions of the Krasnoyarsk krai, Evenkia, and Yakutia (255-332 DU); -by 27-60% on Feb ru ary 18 and March 15 over the north ern re gions of the Krasnoyarsk krai, Yakutia, Evenkia, and the Magadan oblast (187-367 DU); -by 19-51% on March 17-May 14 over the north of Eu ro pean Rus sia, the Arc tic Ocean is lands, West ern Siberia, the north ern re gions of the Krasnoyarsk krai, Yakutia, Evenkia, the Magadan and Irkutsk ob lasts (221-361 DU);

-by 17-27% on May 18-27 over West ern Si be ria, the north ern re gions of the Krasnoyarsk krai, Yakutia, Evenkia, the Ural, and north ern Kazakhstan (265-346 DU).

As noted in [11, 12] , such anom a lies in the win ter-spring sea sons in the north ern re gions of Rus sia were re corded ear lier in 1997 and 2011. How ever, in 2020 the se ries of neg a tive anom a lies was es pe cially du rable and fin ished a month later than the anom aly in 2011. In 2011, the max i mum TO de fi ciency was reg istered at Kotel'nyi Is land sta tion on March 20 and made up 50%. The max i mum TO de fi ciency in 2020 (60%) was reg is tered on March 2 at Kotel'nyi Is land sta tion as well. Such sig nif i cant TO re duc tion af fected the UV irradiance of the earth sur face in the ar eas of the TO anom aly. How ever, due to a very low po si tion of the sun in the high lat i tudes in this sea son, the val ues of the UV in dex [7] [8] [9] did not reach the lev els danger ous for the pop u la tion and did not ex ceed 1. In the sec ond half of May 2020, when the TO de crease reached 24% over the north ern re gions of the Krasnoyarsk krai, Yakutia, and Evenkia, the ex ceed ing of UV-B irradiance of the ter ri tory as com pared to the nor mal made up about 80%, and the UV in dex in the anomaly zone was be low 4 (the level of UV ra di a tion is con sid ered dan ger ous for hu mans at the in dex val ues equal to 6 and more [16] ). RUSSIAN The vari a tions in an nual mean TO val ues dur ing the pe riod from 1997 at three sta tions of the Rus sian ozonometric net work and in two lat i tude zones of the Rus sian Fed er a tion are shown in Fig. 2 . The an nual mean TO val ues were cal cu lated from sat el lite data (http://ozonewatch.gsfc.nasa.gov) for the lat i tude zones and from op er a tional data of M-124 fil ter ozonometers for the sta tions. The con sid er able de ple tion of the ozone layer was ob served from the early 1980s till the mid dle of the 1990s, whereas its rel a tive sta bi li za tion has been ob served since the late 1990s (see Fig. 2 ). Against a back ground of high interannual vari abil ity, it is dif fi cult to state clearly the sig nif i cant TO trends in the mid dle and high lat i tudes. In 2020 all TO anom a lies in the Rus sian Fed er a tion were neg a tive, con sid er able, and to tally rather du ra ble. This led to a sig nif i cant de crease in av er age an nual TO val ues at the sta tions sit u ated in the anom aly zones. Most such sta tions in Rus sia are lo cated in the high lat i tudes. The low TO val ues were also re corded at the Arc tic and sub arc tic sta tions of Can ada and West Eu ro pean coun tries in the win ter-spring pe riod of 2020 [14] . Therefore, there is a dra matic de crease in the an nual mean TO val ues in the lat i tude zone of 60°-90° N and in the trend cal cu lated from the pre sented data. Ac cord ing to Fig. 2 , the trend in an nual mean TO val ues in the lat i tude zone of 60°-90° N is pos i tive and is equal to 0.34 DU per de cade. It is much smaller than the trend cal cu lated from data for 1997-2019. A weak TO growth in the North ern Hemi sphere high lat i tudes is also men tioned in [3, 5, 15] . The trend in an nual mean TO val ues in the lat i tude zone of 30°-60° N re mains negative, its ab so lute value in creased as com pared to the trend com puted from the data for 1997-2019 and is equal to -0.42 DU per de cade.

The ob ser va tions of the Ant arc tic ozone hole (AOH) were con tin ued. The de tailed de scrip tion of the AOH de vel op ment in Au gust-Sep tem ber 2020 is given in [10] . The ba sic vol ume of data on the AOH charac ter is tics is ob tained from sat el lite ob ser va tions us ing the equip ment pro duced in the USA and West ern Eu rope. The area where TO < 220 DU, is con sid ered as the area oc cu pied by AOH. The quan ti ta tive pa rame ters of AOH and Figs. 3 and 4 were taken from the NASA website (http://ozonewatch.gsfc.nasa.gov).

In 2020 the Ant arc tic ozone hole ap peared in early Au gust (as well as in 2017-2019), which corresponds to the av er age time of its oc cur rence, and dis ap peared on the last days of De cem ber (Fig. 3) , which is al most three weeks later than the mean dates of its dis ap pear ance. The AOH area reached the max i mum (24.8 ´ 10 6 km 2 ) on Sep tem ber 20 and then started de creas ing very slowly. By No vem ber 7, it de creased to 20.7 ´ 10 6 km 2 (the mean value for this day is 12.4 ´ 10 6 km 2 ). From No vem ber 18 to De cem ber 2 and from De cem ber 8 to the end of the anom aly, its area ex ceeded the pre vi ously reg is tered max ima.

The con tent of po lar Ant arc tic ozone (the mean TO value in the zone south of 63° S) was be low the multiyear means since the end of April. At the end of Au gust, it was above the nor mal for three days only, started de creas ing rap idly af ter wards, and reached the min i mum of 170 DU on Sep tem ber 27, 2020. The min i mum value for this day is 167 DU, and the ab so lute min i mum of the po lar Ant arc tic ozone is 157 DU. In Oc to ber, po lar ozone con tent started grow ing and reached 214 DU on Oc to ber 13; af ter that it de creased to 189 DU by Oc to ber 28 (the pre vi ously reg is tered min i mum of po lar Ant arc tic ozone for this day is 184 DU). Af ter that, the grad ual growth started, but the pat tern was re peated: hav ing reached the lo cal max ima of 226 DU on No vem ber 8, the value of po lar ozone con tent dropped again to 202 DU on No vem ber 14. On No vem ber 13-30 and De cem ber 12-25, the val ues of po lar Ant arc tic ozone up dated the pre vi ous min ima for these days.

The monthly mean val ues of po lar ozone in the Ant arc tic in No vem ber and De cem ber 2020 were min imal of all pre vi ously reg is tered monthly mean val ues for these months (212.67 and 263.04 DU, re spec -IVANOVA et al. ozone was re corded (as sum ing that the anom aly is the de vi a tion from the mean by ³2.5 SD). Its de fi ciency ex ceeded 2.5 SD on De cem ber 17 and 19-24 and ex ceeded 3 SD on De cem ber 20 and 21. Par a dox i cally, all po lar ozone anom a lies (if they are con sid ered in the above sense as un likely events) that were re corded in the Ant arc tic dur ing the pe riod of 1979-2019 were pos i tive.

It should es pe cially be noted that the change in po lar Ant arc tic ozone in the win ter-spring sea son of 2020 followed to some ex tent the vari a tion in po lar Arc tic ozone in the North ern Hemi sphere winter-spring sea son. On both poles in the men tioned pe riod, the neg a tive de vi a tions of po lar ozone from the multiyear means were grad u ally in creas ing and, hav ing reached the ab so lute max ima, were dis ap pear ing very slowly and for a long time [10] [11] [12] . For com par i son, Fig ure 6 pres ents the de vi a tions of po lar Arc tic ozone from the multiyear means from Jan u ary 1 to April 20, 2020 and the de vi a tions of po lar Ant arc tic ozone from the multiyear means in 2015 and 2020 from Au gust 22 to De cem ber 9 (110 days). The ozone loss in the Antarctic dur ing AOH in 2020 is close to the max ima, and the ozone loss in the Arc tic at the be gin ning of 2020 is more sig nif i cant and lon ger than in the Ant arc tic. The monthly mean val ues of Arc tic po lar ozone in Feb ru ary, March, and April in 2020 were min i mal over all ob ser va tion years (340.2, 330.4, and 344.3 DU, re spec tively). The co ef fi cient of cor re la tion be tween the de vi a tions from the mean val ues of po lar Arc tic ozone in 2020 and the re spec tive de vi a tions of po lar Ant arc tic ozone in the same year presented in the fig ure is equal to 0.83. The co ef fi cient of cor re la tion be tween po lar Ant arc tic ozone in 2015 and 2020 dur ing the pe riod from Au gust 22 to De cem ber 9 is 0.81.

Ac cord ing to sat el lite data, the min i mum TO value south ward of 40° S dur ing AOH in 2020 up dated the pre vi ously reg is tered min ima sev eral times: on Oc to ber 20, 21, 27, No vem ber 2, 4-7, 10-28, De cem ber 9-25, 27, 28; the min i mum TO (94 DU) was re corded on Oc to ber 6, 2020.

Dur ing the whole pe riod of the 2020 AOH, the ozone mass def i cit ex ceeded the multiyear means for 1979-2019. The max i mum ozone mass de fi ciency in 2020 was reg is tered on Oc to ber 8 and made up 35.93 ´ 10 6 t, which is al most 40% higher than the multiyear mean max i mum. From No vem ber 11 to December 2 and from De cem ber 8 till the com plete dis ap pear ance of AOH on De cem ber 28, the ozone mass def i cit ex ceeded the max ima pre vi ously ob served at that time.

The zonal mean tem per a ture in the lat i tude zone of 60°-90° S at the level of 70 hPa in Oc to ber was rising at first, but stopped ris ing in the sec ond half of the month; it var ied within 202-204 K till No vem ber. On Oc to ber 27-29 and No vem ber 1, tem per a ture up dated the pre vi ous min ima for these days, but re mained close to the pre vi ous min ima slightly ex ceed ing them (be low the multiyear means by 8-10 K). From Novem ber 11 to De cem ber 26 (ex cept for De cem ber 8 and 9), tem per a ture con tin ued ris ing but was be low the pre vi ously reg is tered min ima.

The area of strato spheric NAT clouds (formed of ni tric acid trihydrate solid par ti cles), as well as the area of ice strato spheric clouds at the isentropic level of 460 K in 2020 dur ing al most their whole life time was above the multiyear means. The area of strato spheric NAT clouds on Oc to ber 3 and from Oc to ber 18 till their com plete dis si pa tion at the end of the first ten days of No vem ber up dated the pre vi ous max ima. Their for ma tion started close to the av er age long-term dates, and the dis si pa tion was de layed for al most three weeks due to low strato spheric tem per a ture. The dis si pa tion of ice strato spheric clouds fin ished at the end of the first ten days of Oc to ber (al most two weeks af ter the mean date of dis si pa tion), and their area exceeded the pre vi ous max ima on Sep tem ber 30 to Oc to ber 2.

Zonal wind at the level of 70 hPa at 60° S in Au gust and Sep tem ber 2020 up dated the pre vi ously recorded maxima (Au gust 5-7 and Sep tem ber 23-26). Its max i mum speed of 58 m/s was reached on Sep tember 25. In October, the wind started de creas ing grad u ally, most of the time its speed ex ceeded the multiyear means. Then, on Oc to ber 30, the wind dra mat i cally strength ened to 55 m/s and started weak en ing, but was close to the pre vi ous max ima and even up dated them on Oc to ber 31, No vem ber 1, 9, 10, 18, 19, 25-27, Decem ber 10, 13-21, 23, and 24.

Low strato spheric tem per a tures, that were ob served in the Ant arc tic for a long time in the win ter-spring sea son of 2020 thus lead ing to the for ma tion of the great num ber of long-lived strato spheric clouds, and strong zonal winds, caused the sig nif i cant and du ra ble de ple tion of po lar Ant arc tic ozone. Fig ure 7 pres ents the val ues of po lar Ant arc tic ozone av er aged over Au gust-No vem ber in 1979-2020 and the trend curve indi cat ing that the min i mum was passed, and, start ing from the early 21st cen tury, there has been an in crease in po lar Ant arc tic ozone val ues. The es ti mate of the trend in po lar Ant arc tic ozone av er aged over August-No vem ber ob tained a year ago [13] was ap par ently over es ti mated, which was ex pected due to a high vari abil ity of the val ues. The re sults for 2020 made sub stan tial cor rec tion, the trend de creased but re mained pos i tive (0.23 DU per year if tak ing a de riv a tive for 2020 and 1.09 DU if es ti mat ing the lin ear trend based on data since 1997).

In 2020, the mon i tor ing of sur face ozone in Mos cow con tin ued. The rou tine mea sure ments of sur face ozone in Mos cow are car ried out at the Mosekomonitoring en vi ron men tal mon i tor ing net work (https://mosecom.mos.ru/vozdux/). The sur face ozone mea sure ments are per formed at 17 au to matic air pollu tion con trol sta tions lo cated in res i den tial ar eas and close to ma jor high ways. In 2020, sur face ozone values in the Mos cow re gion were ba si cally within the range of vari abil ity of sea sonal long-term val ues [2, 6] ; how ever, in April to Sep tem ber, the monthly mean sur face ozone val ues were 10-15% lower as com pared to the pre ced ing 2019 [13] . The sur face ozone max i mum com monly ob served in April [2] was poorly pro -nounced. The monthly mean sur face ozone value in April was close to that in March. The sec ond sea sonal sur face ozone max i mum, that is most of ten ob served in July or Au gust, was not formed.

The pe cu liar i ties of the sea sonal dis tri bu tion of sur face ozone in 2020 were as so ci ated with sev eral factors. Firstly, the es sen tial in flu ence on sur face ozone was ex erted by weather anom a lies. Sec ondly, the low sur face ozone val ues could be an ef fect of re duced emis sions of pol lut ants to the at mo sphere dur ing the coronavirus pan demic and the self-isolation re gime. In the first half-year of 2020 as com pared to the respec tive pe riod in 2019, the con cen tra tions of car bon ox ide, ni tro gen di ox ide and ox ide, and sul fur di ox ide in air over Mos cow were lower by 11, 22, and 36%, re spec tively; in April, the con cen tra tion of ni tro gen diox ide was smaller by 47% (www.mosecom.mos.ru ).

The ef fect of pos i tive tem per a ture anom aly in 2020 was ev i dently not man i fested due to the ex cess precip i ta tion. In gen eral, the year 2020 was re cord warm over the whole 130-year his tory of reg u lar me te o rolog i cal ob ser va tions; in Mos cow, av er age an nual air tem per a ture was 3°C above the nor mal and was equal to 8.0°C (https://meteoinfo.ru/). The prev a lence of cloudy rainy weather dur ing the pe riod of long-term sea sonal max ima of sur face ozone im peded the in flow of ul tra vi o let ra di a tion re quired for the ozone gen era tion [1] . The an nual pre cip i ta tion nor mal in Mos cow (691 mm) was reached al ready dur ing 8 months, and monthly to tal pre cip i ta tion in May-July ex ceeded the multiyear means by 2-3 times.

The most dra matic vari a tions in sur face ozone, as usual, were ob served in Jan u ary and Feb ru ary, on some days sur face ozone val ues in creased to 70-90 mg/m 3 (Fig. 8) . In March and April, the high est sur face ozone val ues in the year were ob served (0.1-0.12 mg/m 3 ). In May, June, as well as in Au gust and Sep tember, the monthly mean sur face ozone value was be low the multiyear means by 0.05-0.1 mg/m 3 due to weather anom a lies. The an nual min i mum of sur face ozone, as usual, fell on No vem ber-De cem ber. As a dis play of ozone de struc tion in pol luted air [1] , most of the year sur face ozone val ues in the near-highway ar eas were 10-15% lower than in the res i den tial ar eas of the city.

In 2020, the num ber of cases of sur face ozone ap proach ing the max i mum per mis si ble level was smaller than in the pre vi ous years. On June 18-19, the sur face ozone growth to 0.15-0.155 mg/m 3 was re corded; on July 7, sur face ozone ex ceeded MPC m.s and reached 0.167 mg/m 3 . The dra matic in crease in sur face ozone in these short-term ep i sodes oc curred in the af ter noon, when tem per a ture rose to 30°C. At 8 of 17 en vi ronmen tal mon i tor ing sta tions in Mos cow, the av er age an nual sur face ozone value ex ceeded the stan dard for the av er age daily con cen tra tion ac cepted in Rus sia and equal to 0.03 mg/m 3 .

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