Analysis of the effect of soil sealing and landscaping on the thermal field of the Volgograd agglomeration from MODIS data

Abstract

The paper presents the results of studying the influence of landscaping area and surface sealing on the surface temperature of the city. The research object is the territory of the Volgograd agglomeration with a total area of 2.26 thousand sq. km - the cities of Volgograd, Volzhsky and Krasnoslobodsk, as well as the adjacent territories of urban and rural settlements. The data source is the MODIS earth surface temperature information product, 8-day MOD11A2 data (about 10 % of the data is MYD11A2). There are 4 types of underlying surface on the territory of the agglomeration: water bodies, shielded and greened surfaces, wasteland and rain-fed arable land. The degree of soil sealing and landscaping within the borders of administrative divisions is determined. There are differences between different types of underlying surface at different times of the day. During the day, the highest temperatures are observed in vacant lots and rainfed agricultural fields, while water bodies, irrigated land and sealed surfaces are characterized by lower temperatures. A positive high relationship (r = 0.80) between the maximum daily temperature and the area of wasteland, a negative high (r = -0.72) one between the maximum daily temperature and the area of reservoirs were found. At night, on the contrary, buildings, asphalt concrete surfaces and water bodies that have warmed up during the day have a higher surface temperature, a high relationship (r = 0.69) was established between the maximum night temperature and the area of sealed surfaces. The distribution of the heat field in the context of municipalities of the Volgograd agglomeration was considered. Maximum daytime temperatures were observed on the territory of municipalities, which consist of 80-90 % of rain-fed agricultural land, pastures and wasteland. In the most built-up areas of Volgograd, the maximum effect of urban heat island was observed at night. For mean annual temperature, a strong negative relationship was established with the landscaping area (r = -0.81), the average positive with the area of vacant lots (r = 0.61), and the average negative relationship with the area of water bodies (r = -0.43). To determine the optimal ratio of different types of surfaces in the city, the regression dependences of temperatures on the ratio of green, built-up and undeveloped areas (wasteland) were shown. The linear nature of the dependence of average daily temperatures on the ratio of green zones to the sum of built-up and unbuilt surfaces with a correlation coefficient r = 0.95 was established.