A method to detect stratospheric warmings using ionospheric absorption records obtained by an Absorption Meter (method A3) is introduced. The activity of the stratospheric circulation and the D region ionospheric absorption as well as other atmospheric parameters during the winter anomaly experience an abnormal variation. A simultaneity was found in the beginning of abnormal variation in the mentioned parameters, using the absorption records for detecting the initiation of the stratospheric warming. Results of this scientific experience of forecasting in the El Arenosillo Range, are presented

Delamorena, B. A.

English

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ABNORFAL CIRCULATION OIANGES IN _|E NII;TER STRATOSPIIERE,
DETECTED _{ROUGll VARIATIONS OF D REGIOH IOEOSPIIERIC A_SORPTION
B. A. de la Morcna
INTA-CONIE
Iluelva,Spain
ABSTRACT
This p_per intends to introduce a method to detect stratospheric warming.
using ionospheric absorption records obtained by an Absorption Hater (Hethod
A3). The activity of the stratospheric circulation and the D region ionospheric
absorption as well as other atmospheric par_aeters during the winter anomaly
experience an abnormal variation. We have found in our observations a
simultaneity in the beginning of abnormal variation in the mentioned parameters,
using the absorption records for detecting the initiation of the stratospheric
warming. Results of this scientific experience of "forecasting" in the "El
Areas,ills" Range. are presented in this commmication.
INTRODUCTION
For the last ten years, "El Areas.ills" Range has been participating in
international progran_es dedicated to the study of winter stratospheric sudden
warnings with the latmching of =eteorological rockers, and with the analysis and
distribution of the wind and temperature data recorded, following the rules
given by the international scientific coc_unity. ..-
The exceptional advantage of a station for the study of the atmosphere with
ground-based equipment combined with a rocket launching range, has allowed the
simultaneous analysis of the behavior of different par_eters of the _iddle
_>-- atmosphere during the periods considered as winter anomalies. It confirms that.
for tl_ latitude of "El Arenosillo". the abnormal variations of the absorption
par_:neterin the ionospheric D region appear simultaneously with circulation
changes (i.e., rotation of direction) of the stratospheric wind that accompany
the sudden warnings (t_Rh_A, 1981) as ,_ellas a lack of variation of the para-
meter tcnperature in the mentioned period of winter _no_aly.
Analysing Figure Is, it can be observed that in the winter period 1975/76
the zonal circulation in the upper stratosphere which presents west component
coincides with normal values of absorption for that winter period (from 20th
Dec. to 5th Jan., 9th to 18th Jan., and 27th Jan. to 5th Feb.), and on the
. . . . €ontrn,ry,, the abnormal changes.of the zonal circulation to winds of East
component correspond to variations of the absorption which are higher than their
mean value. On the other hand, the period of winter 1976/77 which was
characterized by the absence of circulation ch_ges in the upper stratosphere,
showed a normal behavior of the par_eter absorption in the ionospheric D
region.
Figure Ib is a clear example that the tmperature in the stratosphere
virtually shows the sa_ne variations during unstable periods (as in winter 1975/
76) and in periods of circulation stability (as in winter 1976/77).
Based on this, the present experimental study, whose finhlity is to detect
the appearance of winter stratospheric circulation changes in middle latitudes
and to follow its development through the observation of the abnor=al variations
of the ionospheric absorption par-'_€:ter in D-region, was started. The practical
check-up of the mentioned prediction By.tam has been carried out for the last /
two periods of winter anomaly (1981/82 and (1982/83), using fourteen
meteorological rockets Super-Loki, the stratospheric balloons and continuous
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https://ntrs.nasa.gov/search.jsp?R=19850012148 2020-03-22T18:38:22+00:00Z
Figure Is.
records of the A3-Absorption Meter, showing the result, given in the following.
This scudy ia part of a wide investigation program being developed in "El
Areno_illo" that pretends to develop a simple prediction syst_ of the abnormal
variations of the parameters characterizing the middle atmosphers through the
use o_ ground-baaed equipment.
ANALYSIS OF _IE DATA
The records o_ wind, temperature, and absorption obtained during the two
winter anomaly periods 1981182 and 1982183, once again confirm the aimultemeou.
f
ORIGINAL PAGE 15 47
OF.POOR QUALITY
WINTER ANO_ AJ.y )'_ / "/'G
(I &r_l_ |_PIN,_tWI Tt_ I_UT.
>.....
,3
WINTI_R ANOMALY "._/ 7'?
..... ._
a_
f-'1<-_*¢
_l,.J ./
JANUARY FEBRUARY
Figure Ib,
appearance of disturbances in the normal behavlour of these atmospheric para-
meters (Figures 2 and 3). Figure 2 presents a typical winter anomaly with two
notable stratospheric changes represented in their meridional and zunal
components, being evident in the irregular behavior of the ionospheric absorp-
tion in the D-region, with values which are higher than the mean value
registered from 1976 to 1982. (Ne consider the mean value of absorption
obtained during the solar cycle, represented by the continuous line, as more
significant.)
The periods o_ maximum absorption coincide with a meridional circulation of
, North component in the whole stratosphere, while the normal values of absorption .-
r
/f -
48
WINTr.RANOmALyel,'S2
t¢ A,_ 13TbN-_) T*_ )_ttu.r.
' _ />?Lk'L'_''"/.°_-_'_ ' .c_-,, _--,_,,,,-_',
5 ...-.,o\""_'" :_; . ._
<,,o ..., '... .k: .. ,,,.'-,._ .. ---.,_,_,,v_
JANUARY FEBR_AR_
Figure 2
correspond with a wind circulation of East and West component in the upper ._"
stratosphere. In this diagram, it is easily seen that the meridional circula-
/f- Lion precedes the change of zonal direction to winds of East component. The
/ stratospheric temperature could not be measured during the winter period 1981/82
due to technical problems of the reception system.
Figure 3 analyzes the winter anomaly 1982/83. This was characterized by a
period of circulation stability and of absorption, only altered by two weak
beginnings of meridional circulation changes in the upper stratosphere) which
coincided with sudden increases of ionospheric absorption that were easing off
as the zonal circulation was being re-established. Similar as in the winter
period of 1981/82) meridional winds of North component preceded the changes of ....
zonal circulation in the upper stratosphere. As expected, the temperature did
• , . . not experience any notable changes and its behavior was similar to that observed
during the winter periods of 1975/76 and 1976/77.
Figure 4 gives a synoptic representation of the direction and intensity of
.... the stratospheric wind during the analyzed periods of winter anomaly 1981/82 and
1982/83, offering a more intuitive image of the base used in this possib[e
prediction system.
It can be observed that when the absorption is higher than the established
mean value, a change of meridional direction in the wind circulation of tile
upper stratosphere begins simultaneously (15th to 19th January _982) let to )th
February 1982) 28th of January to [st February 1983 and 15th to 17th February i
1983). On the contrary, periods of normal absorption indicate that the circula- t
tion has been established dominantly in East or West zonal compo.%€:nts, ;
/
It is important to bring out the processes initiating the circulation
change observed during the 28th and 30th of January and Ist of February 1983 by
its possible application to the formation theory of the '_#armings"through geo-
potential fluxes, as well as the sudden and big increase of the ionospheric
absorption in these days, which reached the highest values recorded in El
Arenosillo for the lest ten years.
• / 1 "
/
..... _:,_ _ _'........
W_NT[R _NO_ALY e2/s3
El Awe,',_l_ ($T.IN-t,TW) TIME 1_21U,T.
::_:=:_-:---_-_ [],.,o._
tO
\,',1', , ,/ ,,,,_,,,,,,,,,,,,...._ o_4u._
.tO,.,,,. ' ,,,,,_,,.,,,.. . .. _ ,..,,,,,.,,-_ _ _oitu T.
JANUARY FEBI_UARY
Figure 3.
CONCLUSIONS
- An evident corre_aCiou, betveeu the behaviour o£ the absorption parameter in
the D-region_ and the wind circulation in the upper stratosphere during the
periods of winter anomaly i_ observed°
- Significant increases of absorption indicate the beginning of a circulation
instability (turn-round of the _ind direction) and the establishment of a
meridional component of the wind in the upper stratosphere.
- Normal values of absorption indicate that the circulation is established
dominantly in zonal components. /"
- The mean value of the absorption increases during those winter periods which
are characterized by circulation instability.
- Winds of meridional component precede the abnormal change of the zonal
circulation.
- Since the stratospheric temperature does not experience any notable variations
during the periods of winter anomaly, the system of alert and p=ediction of
sudden warminge (stratalert par_s) has great limitations to be used in the . :!
middle latitude of El Arenosillo.
_ _ ;'
l
5O
WfNT[R ANOMALY 8€/8Z
{L Arll_01_llO|37.1N*G?W| T,_4 12.OlUT
_o 25
JANUARY r_e_uA_
F-- Figure 4a.
WINTE_ ANO_UALY S2tl_
[I A_lr_,Po (_?IN*_.?W) T,me12_1UT.
,,,,,_ _ .Y ...
m I'.
J' ,/
10 ..,.... €,o_ 1976Io t9B3 ,,/
JANUARY rE_RU_RY
Figure 4b. ORIG_AL P,t.C_.".,: i
OF POOR QUALITV
f
51
REFER_ICES
Cisneros, J. H. (1974), I Geophys. Geodesic National Asne_bly, Spain, Vol. I,
, 637.
de la _1orena, B. A. (1981), IV Geophys. Geodesic Natior_l Asse:nbly, Spain.
f


Abnormal Circulation Changes in the Winter Stratosphere, Detected Through Variations of D Region Ionospheric Absorption

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