NEW TECHNOLOGY FOR INVESTIGATION OF URBAN AREA
ATMOSPHERIC BOUNDARY LAYER
Kadygrov E.N.1, Kuznetsova I.N.2, Ivanov A.A.1, Liakhov A.A.3
1 - Central Aerological Observatory, Roshydromet,
3 - Pervomayskaya Str., Dolgoprudny, Moscow Reg., 141700, Russia,
Tel. (+7)(095) 579-9455, Fax.: (+7)(095) 408-7758,
e-mail: src_attex@mtu-net.ru
2 - Hydrometeorological Center, Roshydromet, Moscow, Russia
3 – Moscow Weather Forecast Bureau, Moscow, Russia
1. Introduction
Near-surface data from meteorological stations at the city and in suburb were often used for investigation of
heat island above urban area (Kondratiev and Matveev, 1999). New technology based on consuming of
microwave temperature profilers gave possibility to provide more detail investigation of heat island
parameters. During 2000-2002 three microwave temperature profilers (MTP-5) were used simultaneously in
Moscow region for continuous measurements of atmospheric boundary layer (ABL) temperature profile. One
MTP-5 was installed in the center of Moscow city, the second – in the north part of Moscow (Dolgoprudny),
and the third – in about 50 km westward from the Moscow city center (Zvenigorod experimental site of the
Russian Academy of Science). The MTP-5 instrument is an angular-scanning single channel microwave
radiometer that can provide temperature profile measurements each 10 minutes within the altitude range
0600 m with an accuracy 0,50C (Kadygrov and Pick, 1998; Kadygrov et al 1998; Westwater et al 1999).
It were three main scientific objectives for the simultaneous measurements. The first one was determination
of a Megacity impact to the ABL parameters, which led to creation of heat island (Kondratiev K.Y. and
Matveev L.T., 1999; Golitsin et al, 2002). The second objective was investigation of the ABL stability and
its influence on a radiation balance near the ground surface. For that reason the collection of continuous data
about ABL temperature profiles in different synoptical situations was provided. And the third objective was
in the comparison of simultaneous ABL temperature profiles in Zvenigorod and Dolgoprudny where
radiosonde data was obtained. It is necessary to underline that all preceding climatological data set about
temperature inversion in whole Moscow Region was collected on the base of radiosonde data obtained in
Dolgoprudny. That's why the comparison of ABL temperature profiles in two points separated by space on
tenth of kilometers seems to be very interesting. The measurements were provided as a part of WMO pilot
project GURME – Global Urban Meteorology and Environment (WMO Report, 1999).
2. Analysis of simultaneous remote sensing data
The data received by the use of simultaneous remote sensing of ABL temperature profiles has shown
essential differences of thermal regime in the center of a big city and in suburb. In general: the annual
average ABL condition in the central part of Moscow is close to unstable (adverse conditions), and
deterioration of the vertical exchange conditions has a brief disposition. The monthly averaged temperature
gradients in Moscow city center are presented in Table 1 and Table 2 as a function of a local time (on the
base of MTP-5 data).
The data shows that the atmosphere has unstable temperature stratification during the night and early on the
morning and not only in layer 0-100 m (Table 1) but also in the layer 0300 m (Table 2). Thermal turbulence
has a minimum between 3 and 6 o’clock on the morning. On the base of MTP-5 data, it was experimentally
confirmed that influence of a big city microclimate is comparable with influence of a large-scale
meteorological processes during a number of synoptic situations. Within such events the heating from
anthropogenic sources dominates radiation cooling of the lowest atmospheric layer.
Table 1
Table 2
Monthly averaged temperature gradients (0C/100 m)
Monthly averaged temperature gradients (0C/100 m) in the
in the layer 0-100 m in the center of Moscow city
layer 0-300 m in the center of Moscow city
Time
(h)
October
April
January
July July
2000 2001
Time
(h)
April
January
July
2000
July
2001
0
-0,48
-0,53
-0,51
-0,54 -0,70
0
-0,54
-0,55
-0,75
-0,57
-0,67
3
-0,35
-0,30
-0,54
-0,42 -0,35
3
-0,41
-0,31
-0,77
-0,49
-0,29
6
-0,25
-0,15
-0,56
-0,30 -0,13
6
-0,34
-0,22
-0,78
-0,44
-0,12
9
-0,27
-0,47
-0,58
-0,68 -0,97
9
-0,43
-0,75
-0,81
-0,88
-1,24
12
-0,76
-1,16
-0,70
-0,91 -1,38
12
-0,99
-1,44
-0,97
-1,09
-1,67
15
-0,93
-1,37
-0,80
-1,12 -1,52
15
-1,10
-1,71
-1,04
-1,37
-1,90
18
-0,80
-1,24
-0,71
-1,04 -1,22
18
-0,87
-1,50
-0,92
-1,29
-1,55
21
-0,60
-0,86
-0,73
-0,89 -1,07
21
-0,59
-0,87
-0,95
-1,02
-1,24
October
Table 4
Recurrence of temperature inversion (%)
in Moscow city center
Table 3
Month
I II III IV V VI
VII
VIII IX X XI XII
Temperature (C) at the layer 0-600 m on the base
CLIMATE
49 43 36 35 36 34
35
38 38 33 41 42
(RADIOSONDE)
of MTP-5 data in Moscow city center (M), in
MTP-5
10 (2000г)
Dolgoprudny (D), and in Zvenigorod (Z). March 31,
2000-2001
32 18 35 57 32 23
35
29 27 35 20
3
2001
600 m
500 m
400 m
300 m
200 m
100 m
0m
Time
Station
(2001г)
Fig. 1. Temperature fields in Dolgoprudny, Moscow and
Zvenigorod (23 July 2001).
M
0:00
-1,6
-2,2 -2,9 -3,4 -3,9 -4,4
-5
D
0:00:00 -4,9
-4,6 -4,3 -4,3 -4,5 -4,6
-4,5
Z
0:00
-5,5
-4,5 -4,3 -4,3 -4,3 -4,5
-4,9
M
3:00
-4
-4,2 -4,1 -4,1 -4,2 -4,5
-4,7
D
3:00:00 -6,3
-5,4 -4,7 -4,5 -4,4 -4,4
-4,3
Z
3:00
-8,3
-5,5 -3,9 -3,1 -2,7 -2,9
-2,8
M
D
6:20
-6,2
6:00:00 -7,5
-5,8 -4,8 -4,2 -3,7 -3,5
-6 -4,9 -4,4 -4,4 -4,4
-3,6
-4,4
Z
6:00
-11
-7,6 -5,1 -3,7 -3
-2,6
-2,1
M
9:00
-4,8
-4,8 -4,3 -3,7 -3,4 -3,4
-3,6
D
9:00:00 -5,3
-4,8 -4,2 -4,2 -4,3 -4,5
-4,5
Z
9:00
-7,5
-6,2 -4,8 -3,9 -3,6 -3,4
-3,3
M
12:00
1,9
0,4 -0,9 -2
-4
D
12:00:00 0,8
-0,4 -1,1 -1,8 -2,5 -2,9
-3,4
Z
12:00
1
-0,4 -1,7 -2,7 -3,6 -4,4
-5,1
M
15:00
5,4
3,7 2,6 1,7
-0,3
-0,9
D
16:30:00
Z
15:00
4,1
2,6 1,1 -0,3 -1,4 -2,3
-3,2
M
18:00
7,5
5,7 4,4 3,4
2,3
1,4
0,5
D
18:00:00 5,2
4,2 3,5 2,7
2,1
1,5
0,9
Z
18:00
4,9
3,9 2,6 1,4
0,1
-0,9
-1,8
M
21:00
5,4
5
4,4 3,7
2,9
2,3
1,5
D
21:00:00 2,8
2,9 2,8 2,4
1,9
1,5
1,1
Z
21:01
1,6 2,1 2,3
2,2
1,7
1,3
-0,1
-2,8 -3,5
0,7
Three-points simultaneous remote sensing observations firstly gave detail quantitative parameters of
temperature inversion, ABL stability and it’s differences in the center of urban area and in outside (Table 3).
On the base of MTP-5 data for central part of Moscow were calculated the recurrence of temperature
inversion (Table 4) and were compared with previous radiosonde data (Klinov, 1995).
Remote sensing data has sufficient differences with radiosonde data, particularly during wintertime – from
November up to February. The recurrence of inversion for that time was less for 17-39% with respect to
climatological data. In contrast, the April recurrence was 20% more than climatological data. As it was
mentioned above, climatological data for Moscow city center were calculated on the base of radiosonde data
from Dolgoprudny upper-air station (WMO index 27612). Therefore, the first reason for inversion recurrence
differences may be in urban heat island influence (big difference between surface-atmosphere exchange in
the center and in the north part of Moscow). And the second reason is that those radiosondes are normally
released at 02.30 a.m. local time. But most of temperature inversions in April are started after those time and
that is why were not detected by the radiosonde data.
During simultaneous remote sensing measurements were indicated differences in thermal regime of ABL in
Moscow, in Dolgoprudny and in Zvenigorod station. On the Fig. 1 are presented temperature fields in
Moscow city center, in Dolgoprudny and in Zvenigorod for anticyclone environment (23 July 2001). Fig. 2
presents the parameters of temperature inversions for the same places and within the same time.
Fig. 2. Parameters of temperature inversion in Moscow,
Dolgoprudny and Zvenigorod (23-24 July 2001)
The temperature inversions were indicated in all three points of observations on the night. The deepest one
was about 60C in Zvenigorod, 3.50C – in Dolgoprudny and 1.01.50C – in Moscow, and the inversion height
was 470 m, 370 m and 300 m relatively. Dissipation of inversion is started firstly in Moscow, than in
Dolgoprudny, and than in Zvenigorod.
The quantitative parameters of Moscow heat island are a dark spot in city climate understanding. Heat island
parameters and its seasonal and daily variations were learned during anticyclone conditions. It was classified
two main type of heat island. The specific parameters of the 1-st type were:
– heat dome top has an altitude up to 600 m;
- ABL temperature in the city is higher than in suburb. This type of heat island was indicated mostly in cold
season, or in all seasons with high cloud density, or in warm seasons during cloudless night.
The specific parameters of the second type of heat island were:
– heat dome top has an altitude up to 300 m;
- above this altitude the temperature in suburb is higher than in the city center.
This type of heat island is formed mostly by convective processes. One of an explanation for that type of
head island could be done as the next:
The bottom part of ABL in the city has faster heating because of turbulence exchange.
The top part of ABL has faster cooling due to mixing with cold air from highest altitudes.
The influence of city heat island to the suburb ABL is very dependent on wind speed and wind directions. It
was observed that ABL thermal regime in Dolgoprudny looks like more close to Moscow city center than to
Zvenigorod. On the Fig. 3 are presented some typical results of remote sensing temperature profile received
in Dolgoprudny and in Zvenigorod in comparison with the radiosonde data obtained in Dolgoprudny.
Height [m]
24.06.2001 3:40am
600
MTP-5
Dolgoprudny
500
MTP-5
Zvenigorod
400
Radiosonde
Dolgoprudny
300
200
100
0
12
13
14
15
16
17
18
Temperature [Co]
Fig. 3. Comparison of ABL temperature profiles
In Dolgoprudny and in Zvenigorod (24 June 2001)
3. Conclusions
The results of simultaneous remote sensing measurements of ABL temperature profiles can be summarized
as follows:
- first time it was obtained quantitative parameters of heat island in ABL of Moscow Megacity for
different seasons and miscellaneous of synoptic conditions;
- proposed new technology can be very useful for urban research meteorology and environment
- it was detected that radiosonde data obtained in Dolgoprudny are not fully representative for
determination of ABL parameters on Zvenigorod experimental site because of Moscow Megacity heat
island influence.
4. Acknowledgments
This study was partially supported by the Russian Science Foundation (RFFR grant N 01-05-64138).
5. References
Kadygrov E.N., and D.R. Pick, 1998. The potential for temperature retrieval from an angular-scanning singlechannel microwave radiometer and some comparisons with in situ observations. Meteorological Application, vol. 5,
pp. 393-404
Westwater E.R., Han Y., Irisov V.G., Leuskiy V., Kadygrov E.N., and Viazankin S.A., 1999. Remote sensing of
boundary layer temperature profiles by a scanning5-mm microwave radiometer and RASS: comparison experiments.
Journal of Atmospheric and Ocean Technology, vol. 16, N 7, pp. 805-818
Kadygrov E.N., Gaikovich K.P., Westwater E., Han Y., and Widener K., 1998. Potential performance of boundary
layer temperature profile microwave remote sensing: results of field testing at various latitude zones. Proc. of the
Eighth ARM Science Team Meeting. March 23-27, Tucson, Arizona, pp. 353-356
Kondratiev K.Y., and Matveev L.T., 1999. Main factors in forming of big city heat island. Reports of Russian
Academy of Science, vol. 367, N 2, pp. 253-256 (in Russian)
Golitsin G.S., Kadygrov E.N., Kuznetsova I.N., 2002. Investigations of heat island on the base of microwave remote
sensing data. Reports of Russian Academy of Science, vol. 385, N4, pp 1-8 (In Russian)
Klinov F.Y. (Editor), 1995. Climate, weather and ecology of Moscow. Hydrometeoizdat, Saint-Petersburg, Russia,
p. 437 (in Russian)