BEHAVIOR OF THE 557.7 NM EMISSION IN MLT REGION DURING STRATOSPHERIC

WARMING EVENTS I.V. Medvedeva, A.V. Mikhalev, M.A. Chernigovskaya

Institute of Solar-Terrestrial Physics SB RAS Irkutsk, Russia

Fourth UN/ESA/NASA/JAXA Workshop

“First Results of IHY 2007”Sozopol, Bulgaria, June 2-6, 2008

Observation of emissions of upper atmosphere is an effective method of researching its physical and

chemical properties. Airglow intensities variations are a sensitive indicator of disturbances in the

middle and upper atmosphere. The atomic oxygen [OI] green line is the brightest discrete emission in the visible spectral range in

night airglow of the mid-latitude upper atmosphere; it appears at heights of 85−115 km with the peak at

about 96 km.

Main goal:

to find out the nature of strong disturbances in

behavior of the atomic oxygen 557.7 nm emission observed during the winter periods in the region of Eastern Siberia

in quiet geomagnetic conditions

Analyzed Data• The 557.7 nm airglow observational data

obtained at the ISTP SB RAS Geophysical Observatory (52° N, 103° E);

• The vertical structures of temperature data of satellite NOAA (device TOVS) on 70 and 10 hPa levels for November 1998 through January, 2001. The TOVS data were received and processed at the receiving station of ISTP Remote Sensing Center, Irkutsk;

• The Berlin Meteorological University data on stratospheric warming at 10 hPa level.

(http://strat-www.met.fu-berlin.de) The period under analysis:

1997-2006

Results

Daily mean 557.7 nm nightglow intensity. ISTP SB RAS Geophysical observatory, 1997–

2006, 645 observation nights.

1997 1998 1999 2000 2001 2002 2003 2004 2005 2006Year

0

400

800

1200

1600

2000

I 55

7.7

nm

(R

)

In the period under analysis some significant manifestations of stratospheric warming in 557.7 nm emission variations are possible to

allocate:

1) Intensive local warming in late January–February, 1998, when localization of warming was practically in the place of registration of 557.7 nm emission (53°N, 108°E), where the temperature reached ~250 K. Maximal temperature 267 K was registered in early February in the site with coordinates 74°N, 92°Е. Daily 557.7 nm nightglow intensity grew more than by 100%, temperature growth was about 17 K. On February, 1 the maximal magnitude of intensity was registered, the intensity reached 1500 R; the time shift made about 4 days concerning temperature growth.

2) Warming in January, 2000, above Siberia –

Mongolia – Manchuria which prolonged up to the

early February. Maximal temperature reached

~260 K, it was registered in the center with

coordinates 73°N, 120°E. Strong increase of

557.7 nm emission intensity was observed from

January, 17, the intensity being abnormally high

till January, 22. The highest magnitude of 557.7

nm nightglow intensity exceeding 2000 R was

registered on January, 20.

Variations of daily mean

557.7 nm nightglow

intensity and atmospheric

temperature at the 10 hPa

and 70 hPa levels for

December 1999 – January

2000. Strong intensity

growth after January, 17 is

well seen, the daily mean

intensity grew by about

500 R whereas the

temperature at the 10 hPa

level grew by ~15 K.

215

220

225

230

235

240

245

T, K

10 hPa

200

205

210

215

220

225

T, K

70 hPa

1.12.99 1.01.00 01.02.00 29.02.00Month

0

200

400

600

800

1000

I 55

7.7

nm

(R

)

3) Warming above Asia in the upper stratosphere in early December, 2000. The numerous centers of warm located near the observation place, the maximal temperature reaching ~270 K was registered in the center with coordinates 65°N, 93°Е. The daily mean 557.7 nm nightglow intensity increased by 2.5 times for 4 days, the maximal registered intensity magnitude run up to ~650 R.

4) Warming in mid December 2001 through January 2002 over Siberia, when the temperature at the 10 hPa level grew more than by 30 K. From December, 17 a very strong increase of 557.7 nm emission intensity had been observed. Daily mean 557.7 nm nightglow intensity grew within 2 days from ~500 R up to ~1600 R, the maximal night intensity going up from ~900 R to ~2200 R (on December, 22).

Daily mean 557.7 nm nightglow variations, 2001–2003.

•

2 001 2 002 2 003

Year

0

400

800

1 200

1 600

2 000

I 55

7.7

nm

(R

)

Распределение ежедневных данных областей локализации очагов стратосферных потеплений и

температур в этих очагах для периода 1997-2002 гг.

-180 -90 0 90 180Longitude

0102030405060708090

Lat

itu

de

ISTP Geophysical Observatory52оN, 103оE

Distribution of daily data for the regions of localization of stratospheric warming centers and the

temperatures in these centers for the winters of 1997–2002

(December–March)

ConclusionsOn the basis of the experimental data obtained at the ISTP SB RAS Geophysical observatory (52°N, 103°E) in 1997-2006, some abnormal increases of 557.7 nm airglow intensity caused by stratospheric warming were determined. 557.7 nm airglow variations caused by stratospheric warming are comparable by magnitude with the variations caused by seasonal variation of this emission, and sometimes exceed them essentially.

ConclusionsOn the basis of the experimental data obtained at the ISTP SB RAS Geophysical observatory (52°N, 103°E) in 1997-2006, some abnormal increases of 557.7 nm airglow intensity caused by stratospheric warming were determined. 557.7 nm airglow variations caused by stratospheric warming are comparable by magnitude with the variations caused by seasonal variation of this emission, and sometimes exceed them essentially.The 557.7 nm intensities registered during stratospheric warming in January, 2000 (more than 2000 R) and December, 2001 (more than 2200 R) can refer to extremely registered intensity variation in the middle latitudes.

ConclusionsOn the basis of the experimental data obtained at the ISTP SB RAS Geophysical observatory (52°N, 103°E) in 1997-2006, some abnormal increases of 557.7 nm airglow intensity caused by stratospheric warming were determined. 557.7 nm airglow variations caused by stratospheric warming are comparable by magnitude with the variations caused by seasonal variation of this emission, and sometimes exceed them essentially.The 557.7 nm intensities registered during stratospheric warming in January, 2000 (more than 2000 R) and December, 2001 (more than 2200 R) can refer to extremely registered intensity variation in the middle latitudes.Geographical irregularity of stratospheric warming and their high concentration in the Asian region and, in particular, over Eastern Siberia can form regional (and, probably, latitude-longitudinal) peculiarities of 557.7 nm airglow variations.

Thanks for attention!

• 1 R = 106 photon*cm-2*sec-1

The 557.7 nm airglow arises as a result of 1S1D forbidden transition of atomic

oxygen.The Barth mechanism is now generally accepted as being responsible for the

production of О(1S) :О(3Р) + О(3Р) + М О2* + М,

О2*+ О(3Р) О2*+ О(1S) The rate of the three-body reaction should have a negative temperature coefficient of

about (300/Т)2, and quenching should increase with temperature.

Fig. 4.  Atmospheric profiles from MLS and height-temporal distribution of temperature for the region near Irkutsk during June, 2006.

There is a sharp borderbetween the

stratosphere and mesosphere in summer period.

Fig. 5. Atmospheric profiles from MLS and height-temporal distribution of temperature for the region near Irkutsk during December, 2006.

The different pattern of height-temporaldistribution oftemperature. There

areseveral extremums in temperature

profile.

• Степени несогласованности с линиями регрессии:

• 95 км: • все данные – 116.8• Зима – 117.6• Лето – 106

• 30 км:• Все данные – 123.4• Зима – 126.4