THE MEASURING OF HEIGHT OF THE BOUNDARY BETWEEN THE TROPOSPHERE
AND THE STRATOSPHERE
Kochin A. V.
Central aerological observatory Roshydromet,
Pervomaiskaya st. 3, Dolgoprudny, Moscow Region, Russia
Email: [email protected] Abstract
The estimation of the exact height of the boundary between the air which participates in heat and
mass exchange in the troposphere with the air of the stratosphere is important for climatology.
The troposphere air is involved in mass transfer with the underlying surface. The concentration
of aerosols and dust particles is higher than in the air of stratosphere. The aerosol increases the
attenuation of light. Therefore, the abrupt change in attenuation coefficient of light will
correspond to the height of this boundary. A method is developed for determining this height
according to the data of simple and cheap optical sensor of radiosonde
Key words: boundary between troposphere and stratosphere, attenuation, optical sensor,
radiosonde
1. Introduction
The estimation of the exact height of the boundary between the air which participates in heat and
mass exchange in the troposphere with the air of the stratosphere is important for climatology
and a number of practical problems, for example, detection of volcanic dust and smoke particles.
This boundary is located in the area of tropopause but its exact location is unknown. The
troposphere air is involved in mass transfer with the underlying surface. The concentration of
aerosols and dust particles is higher than in the air of stratosphere. The aerosol increases the
attenuation of light. Therefore, the abrupt change in attenuation coefficient of light will
correspond to the height of this boundary. This height can be measured by using the
actinometrical radiosondes which are quite expensive. A method is developed for determining
this height according to the data of optical sensor of radiosonde. The proposed sensor is simple
and cheap.
2. The equipment and method of measurement
The original purpose of the investigation was the goal to create cheap sensor for measuring of
the cloud top height by using usual radiosonde. The photodiode of generating type (sensitive
visible and near-infrared regions of the spectrum) was used to measurements. The sensors were
installed on the radiosonde and oriented up along the rail. The radiosonde measured the sensor
signal by integrated ADC and transmitted a signal with a period of 1 second. The data were
recorded on the computer and after the end of launch data were processed. There were done 15
launches in various conditions on aerological station Dolgoprydnaya (27612). It turned out
during processing of the data that the sensor is able to evaluate the attenuation of optical waves
in the atmosphere and determine the vertical profile of the coefficient of attenuation.
3. The results of the measurements.
The sensor sign
nal has stronngly fluctuaations due to
t swingingg of the raddiosonde. The attenuation
coeffficient is thee derivativee of the signnal. Therefoore it requirres advanceed signal proocessing. Data
D
proceessing was carried out by two wayys.
1. Thhe first methhod is averaaging of signals for 3000 points (abbout 1500 meters)
m
and tthe calculation
of the incrementt signal. It was
w based on
o spatial avveraging of the signal,
2. Thhe second method
m
is baased on the selection of
o signal maaximum andd then and the
t calculation
of the incrementt signal. This method provided
p
higgh resolution.
Fig.11. The reduuction in liight intensiity calculatted by the first methood in triplee launch. The
T
absciissa shows the
t meters. The blue linne is temperature.
The rresults of trriple launchh given in thhe fig. 1. Thhree radioso
ondes were launched simultaneou
s
usly
with a spatial resolution
r
o 2 Km hoorizontally. The repeattability of the measurrements in the
of
tropoosphere is very
v
high. Prrofile of atttenuation inn the stratospphere is meeasured worse. This is due
d
to laarge variatioons in radioosonde. How
wever, this method caannot show the fine sttructure of the
attennuation.
Fig.22. The redu
uction in ligght intensity calculated by the seecond methhod in triple launch. The
T
absciissa shows the
t meters. The brown line is tempperature.
The second metthod of calcculating thee attenuationn gives the opportunity
y to see thee fine structuure
of thhe tropospheere (Fig.2).. There werre temperatture inversioons at altituudes approxximately 25500
and 55000 meterrs. It is know
wn that thee aerosol acccumulates under
u
the innversion soo the air in the
inverrsion is trannsparent, andd the attenuuation becom
mes less.
A shharp decreaase in attennuation is always preesent at a height cloose to the height of the
tropoopause, Fig..3.
Fig.33. The variaability in trropopause height
h
(red line) and a sharp decrrease in atteenuation (b
blue
line). The y-ordiinate is metters; the x-ccoordinate iss the ordinaal number off the launchh.
The formation of tropossphere inveersion layeer (TIL), i.e.
i
sharp increase inn temperatuure
immeediately above the troopopause, still not receeived sufficcient explannation. Sim
milarly, optiical
phennomena in TIL
T has nott yet receiveed an explaanation. Thee airplane pilots
p
detectted featuress in
the ooptical properties of TIIL who see the haze at the intersection of thee plane of thhe tropopauuse.
One likely explanation mayy be the inccreased conncentration of aerosolss at this altitude, whichh is
celebbrated in a number
n
of experiments
e
s.
4. Coonclusions
The developed
d
s
sensor
can be
b used to estimate
e
thee vertical profile of atteenuation coeefficient in the
atmoosphere simu
ultaneouslyy with the measuremen
m
nt of CTH. It
I is advisabble to continnue researchh to
obtaiin informatiion about optical
o
prop
perties of thhe atmospheere. It woulld be usefuul to conducct a
trial operation of the opticaal sensor on some aerollogical statioons in a diff
fferent climaate zones.
ACK
KNOWLED
DGEMENT
T
The aauthor would like to thhank V. Fom
menko for assistance
a
in
n experimennts and I. Gubarchuk
G
f
for
data processing..
REF
FERENCES
S
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K
Em
mmanuel Brrocard ,Solaar and therm
mal radiation profiles and
a
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ysical reseaarch letters, vol. 39
2.E. M
M. Feigelsoon Fluxes off Solar Rad
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