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Investigation of 3D structure of urban heat island of Moscow city … · 2016-08-09 ·...
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Microwave temperature profiler MTP-5 is produced by Russian company Attex (http ://attex.net/). It makes measurements up to 1000 m above the instrument and gives the same performance in all weather conditions. Declared temperature accuracy is 0.2 – 1.2 ⁰. Investigation of 3D structure of urban heat island of Moscow city with application of microwave temperature sounding and high resolution regional modelling with data assimilation Mikhail Varentsov (1,2) , Otto Chkhetiani (2) , Leonid Maximenkov (2) , Pavel Konstantionov (1) (1) Lomonosov Moscow State University, Faculty of Geography, Department of Meteorology and Climatology, [email protected] (2) A. M. Obukhov Institure of Atmosphere Physics RAS Development and validation of urban-scale numerical weather and climate models requires better understanding of three-dimensional structure of urban heat island, including its shape and vertical thickness. An attempt to investigate 3D structure of the urban heat island of Moscow city, which forms the biggest urban agglomeration in Europe, was made during September-October 2014. Three similar MTP-5 microwave temperature profilers, which are available to measure temperature at the heights from 0 to 1000 meters with 50-m resolution, were install at three points in the city and its suburbs. These measurements were joined in single database with weather observations at more than 15 meteorological stations, located in the city and neighborhood. Observations with MTP-5 profilers were taken one month. During this period, different weather conditions were observed, including periods of calm and clear anticyclonic weather, when urban heat island intensity at ground level reached values up to 8 ⁰C, with mean value about 1.8 ⁰C. Temperature difference between urban territory and suburbs over the surface, according MTP-5 measurements, was also significant (up to 2 ⁰C at several moments) until the height of 1000 m. Measurements of temperature profilers were used for data assimilation in numerical experiments with WRF (Weather Research & Forecasting) model, launched with resolution about 1 km for Moscow region. The effect of data assimilation on forecast quality for rural and urban territories was examined and evaluated. Observations of the MTP-5 temperature profilers and meteorological stations and modelling results were used for investigation of the 3-dimentional structure of urban heat island and It’s dependence on synoptic conditions and wind direction. Abstract Dolgoprudyy site (northern suburb) MSU site (city park) Kosino site (eastern suburb) MTP5 microwave temperature profiler Observations description & analysis Mean temperature distribution (cases with UHI at city center > 2 ⁰C) : Mean temperature distribution (all cases with data available): Measurements period: 20.09.2014 – 22.10.2014 -4 -2 0 2 4 6 8 24 25 26 27 28 29 30 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 UHI intensity, ⁰C Day of month UHI at city center (2m) UHI at MSU (2m) ∆T (MSU - Kosino, 0 m) ∆T (MSU - Kosino, 50 m) ∆T (MSU - Kosino, 100 m) ∆T (MSU - Kosino, 200 m) ∆T (MSU - Kosino, 300 m) UHI intensity dynamics at different heights: -4 -2 0 2 4 6 8 24 25 26 27 28 29 30 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 UHI intensity, ⁰C Day of month UHI at city center (2m) UHI at MSU (2m) ∆T (MSU - Doloprudnyy 0 m) ∆T (MSU - Doloprudnyy 50 m) ∆T (MSU - Doloprudnyy 100 m) ∆T (MSU - Doloprudnyy 200 m) ∆T (MSU - Doloprudnyy 300 m) Data sources: • MTP-5 profilers at 3 points • Meteorological observatory of Moscow University (MSU) • Local weather stations & MosEcoMonitoring stations 3D-structure of the urban plumes Case with north-west wind (02-Oct-2014 00 MSK) Upwind city edge (Dolgoprudnyy) Downwind city edge (Kosino) Upwind city edge (Kosino) Downwind city edge (Dolgoprudnyy) Case with south-east wind (09-Oct-2014 06 MSK) Location of MTP devised and sounding directions: Kosino Dolgoprudnyy MTP-5 Weather station Ecological monitoring st. 0 5 10 15 20 25 Frequency, % Inversion frequency (dt/dz > 0.1⁰С/100 m) MSU Dolgoprudnyy Kosino -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 MSU - Kosino MSU - Dolgoprudny Correlation between UHI at city center and temperature difference between urban and city MTP measurements at different heights WRF simulations with temperature profiles assimilation H6 H6_as H12 H12_as h18 h18_as h24 h24_as Mean RMSE 1.80 1.80 1.97 1.92 1.96 1.95 2.08 2.06 City center RMSE 1.63 1.59 1.77 1.71 1.71 1.68 1.79 1.75 Mean bias -0.13 -0.10 -0.07 -0.14 0.03 0.02 0.04 0.06 City center bias -0.56 -0.54 -0.49 -0.55 -0.34 -0.37 -0.31 -0.31 Surface elevation a.s.l, m Data shows that described in theory so-called “urban plumes” were observed in cases with significant UHI intensity and weak wind. They were accompanied by the shift of heat island core to downwind side of the city. Landuse classed for WRF. Urban is dark-blue (1) Model configuration (smaller nested domain): 97 (w-e) x 73 (s-n) x 35 (vert) cells, time_step = 60 sec, dx = dy = 1000 m, sf_urban_physics = 0 (None), sf_surface_physics = 2 (Noah Land Surf.) bl_pbl_physics = 2 (Mellor-Yamada-Janjic) Scheme of the model runs: Forecast starts from original initial conditions from basic domain and from corrected initial conditions (with assimilated temperature profiles for initial moment) every 6 hours, for 24 hours – producing forecasts for 6 (h6), 12 (h12), 18 (h18) and 24 (h24). Model runs for 26 Sept – 18 Oct 2014. Comparison with observation at weather stations: Mean temperature (H24 forecast without assimilation & observations) Mean night (0 UTC) temperature (H24 forecast without assimilation & observations) Mean difference ∆T = T H24 with assimilation –T H24 without assimilation Mean night (0 UTC) difference ∆T = T H24 with assimilation –T H24 without assimilation 1. Temperature profiles, averaged for whole observation period, hadn’t shown significant urban-caused anomalies , probably because of unfavorable synoptic conditions and gaps in the data. But averaging for the cases with significant UHI (higher than 2 ⁰C) had shown that vertical extent of UHI in average was about 200 m and extent of overlaying urban cool island (UCI) from 200 to 600 m; 2. Lower ratio of inversions was observed over the city then over suburbs in lower 100 m (UHI) and higher ration – from 100 to 600 m (UCI); 3. At Kosino suburb site positive correlation between UHI intensity over ground (2m) and in UHI intensity in different heights was observed. At Dolgoprudnyy suburb site negative correlation was observed. 4. Cases with shifted by wind UHI warm core and urban plumes over the city were observed; 5. Comparison between WRF model simulations and observations shows that model relatively good simulates temperature regime of Moscow city (including UHI intensity variation), but temperature profiles assimilation hadn’t provided any significant effect on forecast quality. Summary UHI UCI (urban cold island) UHI UCI (urban cold island) The study was supported by Russian Scientific Fund (RSF), project №14-27-00134
Transcript of Investigation of 3D structure of urban heat island of Moscow city … · 2016-08-09 ·...
Microwave temperature profiler MTP-5 is produced by Russian company Attex (http://attex.net/). It makesmeasurements up to 1000 m above the instrument and gives the same performance in all weather conditions.Declared temperature accuracy is 0.2 – 1.2 ⁰.
Investigation of 3D structure of urban heat island of Moscow city with application of microwave temperature sounding and high resolution regional modelling with data assimilationMikhail Varentsov(1,2), Otto Chkhetiani(2), Leonid Maximenkov(2), Pavel Konstantionov (1)
(1) Lomonosov Moscow State University, Faculty of Geography, Department of Meteorology and Climatology, [email protected](2) A. M. Obukhov Institure of Atmosphere Physics RAS
Development and validation of urban-scale numerical weather and climate modelsrequires better understanding of three-dimensional structure of urban heat island, including its shape andvertical thickness. An attempt to investigate 3D structure of the urban heat island of Moscow city, which formsthe biggest urban agglomeration in Europe, was made during September-October 2014. Three similar MTP-5microwave temperature profilers, which are available to measure temperature at the heights from 0 to 1000meters with 50-m resolution, were install at three points in the city and its suburbs. These measurementswere joined in single database with weather observations at more than 15 meteorological stations, located inthe city and neighborhood.Observations with MTP-5 profilers were taken one month. During this period, different weather conditionswere observed, including periods of calm and clear anticyclonic weather, when urban heat island intensity atground level reached values up to 8 ⁰C, with mean value about 1.8 ⁰C. Temperature difference between urbanterritory and suburbs over the surface, according MTP-5 measurements, was also significant (up to 2 ⁰C atseveral moments) until the height of 1000 m.Measurements of temperature profilers were used for data assimilation in numerical experiments with WRF(Weather Research & Forecasting) model, launched with resolution about 1 km for Moscow region. The effectof data assimilation on forecast quality for rural and urban territories was examined and evaluated.Observations of the MTP-5 temperature profilers and meteorological stations and modelling results were usedfor investigation of the 3-dimentional structure of urban heat island and It’s dependence on synopticconditions and wind direction.
Abstract
Dolgoprudyy site (northern suburb)
MSU site (city park)
Kosino site(eastern suburb)
MTP5 microwave temperature profiler
Observations description & analysis
Mean temperature distribution (cases with UHI at city center > 2 ⁰C) :
Mean temperature distribution (all cases with data available):
Measurements period: 20.09.2014 – 22.10.2014
-4
-2
0
2
4
6
8
24 25 26 27 28 29 30 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
UH
I in
ten
sity
, ⁰C
Day of monthUHI at city center (2m) UHI at MSU (2m)
∆T (MSU - Kosino, 0 m) ∆T (MSU - Kosino, 50 m)
∆T (MSU - Kosino, 100 m) ∆T (MSU - Kosino, 200 m)
∆T (MSU - Kosino, 300 m)
UHI intensity dynamics at different heights:
-4
-2
0
2
4
6
8
24 25 26 27 28 29 30 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
UH
I in
ten
sity
, ⁰C
Day of monthUHI at city center (2m) UHI at MSU (2m)
∆T (MSU - Doloprudnyy 0 m) ∆T (MSU - Doloprudnyy 50 m)
∆T (MSU - Doloprudnyy 100 m) ∆T (MSU - Doloprudnyy 200 m)
∆T (MSU - Doloprudnyy 300 m)
Data sources:• MTP-5 profilers at 3 points• Meteorological observatory of Moscow University (MSU)• Local weather stations & MosEcoMonitoring stations
3D-structure of the urban plumes
Case with north-west wind (02-Oct-2014 00 MSK)
Upwind city edge
(Dolgoprudnyy)
Downwind city edge(Kosino)
Upwind city edge(Kosino)
Downwindcity edge
(Dolgoprudnyy)
Case with south-east wind (09-Oct-2014 06 MSK)
Location of MTP devised and sounding directions:
Kosino
Dolgoprudnyy
MTP-5
Weather
stationEcological
monitoring st.
0
5
10
15
20
25
Fre
qu
en
cy, %
Inversion frequency (dt/dz > 0.1⁰С/100 m)
MSU Dolgoprudnyy Kosino
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
MSU - Kosino
MSU - Dolgoprudny
Correlation between UHI at city center and temperature difference between urban and city
MTP measurements at different heights
WRF simulations with temperature profiles assimilation
H6 H6_as H12 H12_as h18 h18_as h24 h24_as
Mean RMSE 1.80 1.80 1.97 1.92 1.96 1.95 2.08 2.06
City center RMSE 1.63 1.59 1.77 1.71 1.71 1.68 1.79 1.75
Mean bias -0.13 -0.10 -0.07 -0.14 0.03 0.02 0.04 0.06
City center bias -0.56 -0.54 -0.49 -0.55 -0.34 -0.37 -0.31 -0.31
Surface elevation a.s.l, m
Data shows that described in theory so-called “urban plumes” were observed in cases with significant UHI intensity and weak wind. They were accompanied by the shift of heat island core to downwind side of the city.
Landuse classed for WRF. Urban is dark-blue (1)
Model configuration (smaller nested domain):97 (w-e) x 73 (s-n) x 35 (vert) cells,
time_step = 60 sec,
dx = dy = 1000 m,
sf_urban_physics = 0 (None),
sf_surface_physics = 2 (Noah Land Surf.)
bl_pbl_physics = 2 (Mellor-Yamada-Janjic)
Scheme of the model runs:Forecast starts from original initial conditions from basic domain and from corrected initial conditions (with assimilated temperature profiles for initial moment) every 6 hours, for 24 hours – producing forecasts for 6 (h6), 12 (h12), 18 (h18) and 24 (h24). Model runs for 26 Sept – 18 Oct 2014.
Comparison with observation at weather stations:
Mean temperature (H24 forecast without assimilation & observations)
Mean night (0 UTC) temperature (H24 forecast without assimilation & observations)
Mean difference ∆T = T H24 with assimilation – T H24 without assimilation
Mean night (0 UTC) difference ∆T = T H24 with assimilation – T H24 without assimilation
1. Temperature profiles, averaged for whole observation period, hadn’t shown significant urban-causedanomalies , probably because of unfavorable synoptic conditions and gaps in the data. But averaging forthe cases with significant UHI (higher than 2 ⁰C) had shown that vertical extent of UHI in average wasabout 200 m and extent of overlaying urban cool island (UCI) from 200 to 600 m;
2. Lower ratio of inversions was observed over the city then over suburbs in lower 100 m (UHI) and higherration – from 100 to 600 m (UCI);
3. At Kosino suburb site positive correlation between UHI intensity over ground (2m) and in UHI intensity indifferent heights was observed. At Dolgoprudnyy suburb site negative correlation was observed.
4. Cases with shifted by wind UHI warm core and urban plumes over the city were observed;5. Comparison between WRF model simulations and observations shows that model relatively good simulates
temperature regime of Moscow city (including UHI intensity variation), but temperature profilesassimilation hadn’t provided any significant effect on forecast quality.
Summary
UHI
UCI (urban cold island)
UHI
UCI (urban cold island)
The study was supported by Russian Scientific Fund (RSF),
project №14-27-00134
