Assessment of soil microclimate in an urban park of Budapest, Hungary

Abstract

Investigation of urban parks is a particular research section in the frame of urban geology, with increasing social importance. Both natural and anthropogenic factors affect these green sites, giving special scientific importance to their investigation. Thus, the behavior of such a ’composite’ system is expected to be quite complex. Based on the general circumstances, a research project was introduced in 2016 in the former Mining and Geological Survey of Hungary (now: Supervisory Authority for Regulatory Affairs). The ongoing project was focused on the behavior of urban parks. Within the frame of this research, between 2016 and 2019, field studies were started in 4 parks of Budapest. This paper is targeting one of these parks, namely Honvéd square. Our objective is to understand the behavior of urban parks under special conditions (e.g., during heat island effects) by getting information from well-defined positions. This can be essential to perform more sustainable water management in an urban park. Within the frame of the field works soil temperature and soil moisture measurements were being recorded manually every week in every park, at four different locations within a park. Observation points were selected to describe the different microclimates of the parks. A statistical analysis of the data reveals that the urban heat island (UHI) effect is reflected in soil temperatures at a citywide scale and that by moderating urban soil surface temperature extremes, trees and shrubs may help to reduce the adverse impacts of urbanization on microclimate, soil processes, and human health. It can be stated, that beside the manual measurements, the automated soil temperature detection was significantly influenced by soil depth at the Honvéd square park. At 100 cm below the surface, the soil temperature is relatively constant. It was approved that not only do deeper soil layers undergo less drastic seasonal temperature fluctuations but also the changes taking place lag further behind those of shallower soil layers.