The paper presents the first results on the study of the temperature regime of the Novosibirsk agglomeration according to the data of satellite sensing.
and connection to a geographic information system, which allows visualizing data in the form of sets of thematic layers, but makes it difficult to use a large number of satellite images using complex processing functions, the hVault technology proposed in [14] provides virtual integration of in the data archive in a relational DBMS. This technology is based on the principle of presenting data in the form of a set of tables containing satellite image data or information products built on their basis, with the subsequent implementation of algorithms for analyzing spatio-temporal series by means of a DBMS.
To solve this problem, we used products obtained as a result of processing data from Terra / MODIS devices. The
temperature values reconstructed from the measurements of the intensity of infrared radiation recorded in channels 31
(wavelength - 11 μm) and 32 (wavelength - 12 μm) based on the algorithm [
The analysis of the spatiotemporal series of the surface temperature of the territory of the Novosibirsk agglomeration was carried out according to the calculated average temperature in pixel for each calendar year from 2001 to 2014 (data taken from the ICT SB RAS archive) for the whole year; for a snowless period from April 1 to October 31; for the winter period from November 1 to March 31. As an example of the results of the study, we consider the period from April 1, 2006 to March 31, 2007, which we will divide into two: “conditionally” snowless from April 1 to October 31, 2006 and “conditionally” snowy from November 1, 2006 until March 31, 2007 (the term “conditionally” appeared due to the fact that in different years the establishment of snow cover and its disappearance even within the city occur on different days).
The process of studying the temperature regime of the Novosibirsk agglomeration consistently consisted of solving the following problems:
1. assessment of the spatial structure of the surface temperature of the territory from the position of its heterogeneity by the average temperature in a pixel over a period;
2. obtaining comparative estimates of surface temperature in different seasons by the average temperature in a pixel for a period; 3. revealing the structure of the thermal field in the city of Novosibirsk by the average temperature in a pixel; 4. identification of thermal anomalies, which are statistical outliers in the spatiotemporal series of surface temperature data, according to the Robust Satellite Techniques (RST) method;
5. Testing the hypothesis of the presence of the “heat island” in the city of Novosibirsk and the settlements included in the Novosibirsk city agglomeration. 2
Consider the results for each task.
1. In fig. Figure 2 shows the distribution of the average temperature in a pixel for a calendar year and from 2001 to 2014. The structure of the thermal field, as expected, is heterogeneous. The first thing that attracts attention is the “warm” water surfaces (Ob reservoir, Berdsky Bay and the Ob River). The minimum average temperature in the study area was –6.3 ° С, the maximum: + 1.7 ° С. Further, we note a higher average surface temperature in comparison with the surrounding area inside the city of Novosibirsk (we will talk about the temperature distribution inside the city in more detail later). The average temperature inside the city limits exceeds the average temperature of remote areas by 4–6 degrees. It can also be seen that the average surface temperature inside small cities and settlements that are part of the Novosibirsk agglomeration (Berdsk, Gorny, Kolyvan, Kochenevo, Chik) is 2–4 degrees higher than the average temperature of nearby territories, but lower than in Novosibirsk (approximately the same as on the outskirts of Novosibirsk). But in Iskitim, the average temperature is close to the average temperature in Novosibirsk, the difference is 1-2 degrees.
2. From April 1 to October 31, 2006, within the analyzed range covering Novosibirsk and its environs (Fig. 1), the average surface temperature varied from + 0.5 ° С to + 12 ° С. In most of the territory, the average temperature in a pixel is below + 6.3 ° C. In the territory of Novosibirsk, the average temperature is unevenly distributed. Most of the city’s territory has a surface temperature of + 8 ° С to + 11 ° С (Fig. 3, a). In the cities of Berdsk and Iskitim, the average surface temperature is + 8-9 ° C, which is comparable to the average temperature in Novosibirsk. Whereas the average temperature in a pixel for the indicated snowless period in the city of Ob and in small villages (Gorny, Kolyvan, Koltsovo, Kochenevo, Krasnoobsk, Moshkovo, Chik) does not differ from the temperature of neighborhoods with no urban development.
Consider the period from November 1, 2006 to March 31, 2007, when snow cover is established almost annually in the study area and winter begins. Average surface temperature in 2006–2007 varied from –21.5 ° С to –10.7 ° С. In most of the territory, the average temperature in a pixel is below –18 ° С. In cities of regional subordination (Berdsk, Iskitim, Ob) and small villages (Gorny, Kolyvan, Koltsovo, Kochenevo, Krasnoobsk, Moshkovo, Chik) the average temperature in a pixel is higher: about –16 ° С. In the territory of Novosibirsk, the average temperature is unevenly distributed. Most of the city’s territory has a surface temperature of –12.5 to –13.5 ° С (Fig. 3, b). а) б)
3. In fig. Figure 4 presents a fragment of the map of Novosibirsk with the presentation of only two intervals with the highest temperature for the winter period (above –13 ° C), which allows us to identify the structure of the heat field in the city. On the territory of the main subject of agglomeration - the city of Novosibirsk - there are several areas with a higher average temperature in relation to the rest of the territory: this is Zaeltsovsky Park, a part of the city bounded by Dusi Kovalchuk, Vladimirovskaya, Factory, Nikitina, Volochaevskaya, Uchitelskaya, George Kolonda. In the left-bank part of the city, an area stands out, bounded by the streets of Nemirovich-Danchenko, Stantsionnaya, with a higher average temperature relative to the whole part of the city.
4. For completeness of the study of the distribution of the thermal field of urban agglomeration, an analysis was
made of the spatiotemporal series of surface temperature of the territory of the Novosibirsk agglomeration according
to the RST method (Robust Satellite Techniques) [12] in order to identify statistical emissions. The method is based
on a statistical analysis of satellite data sets of the Earth's surface temperature for a selected area. To eliminate the
influence of the seasonal variation in temperature and heterogeneity of the relief, data is converted. First, the time
interval of interest to the researcher is recorded, the temperatures are extracted on these days of the year for several
years. Next, the RST index is calculated for the selected area. The main advantage of the index is that when choosing
a region and a time interval of suitable sizes, it eliminates the influence of temperature variations caused by climatic
processes, heterogeneity of the relief, and weather conditions [
The RST method was applied for each year, from 2001 to 2014, and for each period: from April 1 to October 31 and from November 1 to March 31.
The result of 2006 from April 1 to October 31 is interesting. This year, during the considered time interval, thermal anomalies were revealed that manifested themselves in different areas of Novosibirsk: on the territory of Kudryashovsky Bor, Krivodanovka, almost the entire territory of the city turned out to be anomalous with varying degrees of intensity. Ob city was also abnormal. Chik, Kochenevo, Kolyvan, Gorny, Iskitim, a little bit of Berdsk.
5. Based on the results of the research, the hypothesis of the existence of the urban “heat island” for the city of Novosibirsk and for the city of Iskitim was confirmed. However, for smaller urban formations, “heat islands” were not found. 3
The problem of the "thermal islands" of cities is becoming especially relevant at the present stage of the development of science in connection with the contribution of cities to processes affecting the ecology of the territory. Thermal images reveal the spatial structure of the “thermal islands” of cities. Such data may be images obtained from the MODIS spectroradiometer installed on the Terra satellite. Despite the low spatial resolution of such images, there is an advantage of the applicability of these materials in the study of the temperature regime of urban agglomeration. This is a high repeatability and two shooting channels of thermal infrared shooting. A wide coverage and low spatial resolution make it possible to conduct studies not only of the "thermal island" of the city, but also to evaluate its impact on the surroundings, the total thickness and extent of such a "thermal island".
For the first time, according to space monitoring, an analysis of surface temperature for the Novosibirsk city agglomeration has been performed. The structural features of the heat field in summer and winter, as well as the limits of the territorial variability of the temperature of the urban surface are established. The thermal field within the city is very heterogeneous.
Revealing the structure of the thermal field of the Novosibirsk agglomeration will allow, in the authors' opinion, sound planning of the territory development taking into account the requirements for creating a comfortable living environment. [2] Кораблёва Е.Г., Ленская О.Ю. Исследования острова тепла города Челябинска в зимний период // Вестник Челябинского государственного университета. Экология. Природопользование. 2010. № 8 (189). Вып. 4. С. 15–23. [3] Погорелов А.В., Липилин Д.А. Тепловой «портрет» города Краснодара по данным спутниковых снимков // Вестник ПНИПУ. Прикладная экология. Урбанистика. 2016. № 4. С. 32–45. [4] Cheval S., Dumitrescu A. The July urban heat island of Bucharest as derived from MODIS images // Theoretical and Applied Climatology. 2009. № 96. P. 145–153. [5] Pu R., Gong P., Michishita R., Sasagawa T. Assessment of multi-resolution and multi-sensor data for urban surface temperature retrieval // Remote Sensing of Environment. 2006. № 104. P. 211–225. [6] Коновалова Т.И., Трофимова И.Е. Картографирование экологического состояния урбанизированных территорий на основе материалов дистанционных исследований Земли // Исследования Земли из космоса. 2008. № 4. С. 36–44. [7] Voogt J.A., Oke T.R. Thermal remote sensing of urban climates // Remote Sensing of Environment. 2003. № 86. P. 370–384. [12] Tramutoli V., Di Bello G., Pergola N. and Piscitelli S. Robust satellite techniques for remote sensing of seismically active areas / // Annals of Geophysics. 2001. 44(2). P. 295–312.