Applicability of UAV in Urban Thermal Environment Analysis

Abstract

Urban heat islands occur due to increases in the extent of artificial surfaces such as concrete, asphalt and high-rise buildings. In this regard, research into the use of satellite thermal infrared images for thermal environment analysis of urban areas is being carried out. However, such analysis of the characteristics of individual land cover with low-resolution satellite images suffers from limitations because land cover patterns in urban areas are complicated. Recently, UAV has been widely used, which can compensate for this limitation as it is able to acquire high-resolution images. In this paper, the accuracy of UAV infrared images is verified and the applicability of UAV in urban thermal environment analysis is examined by comparing the results with land surface temperatures from Landsat 8 thermal images. The results show a high positive correlation of temperature values at 0.95, and no statistically significant difference between the two groups. Comparisons of land surface temperature according to land cover showed that the largest difference observed was 4.63℃ in the Used area, and UAV images with small cell units reflected various surface temperatures. Furthermore, it was possible to analyze the surface temperatures of various green spaces such as wetlands and street tree areas, which can lower surface temperatures in urban areas, with street tree shadows reducing surface temperatures by about 4-6℃. UAV can easily and rapidly measure the surface temperature of urban areas and is able to analyze various types of green spaces. Thus, this is an effective tool for thermal environment analysis in urban areas to aid in the design or management of urban green spaces, as it can allow for land cover and the effects of the various green spaces.

Feasibility and accuracy assessment of UAV, aircraft, and satellite-based remote sensing for irrigation management using canopy temperature and NDVI.

“…Quantification of water requirements has been a significant application of remote sensing in precision agriculture. Remote sensing has been extensively used in monitoring plant water status using satellites [Hussain et al, 2020;Krishna et al, 2021;Ndlovu et al, 2021;Sibanda et al, 2021;Xu et al, 2020] and UAVs [Jaganmohan et al, 2016;Kang et al, 2018;Yang et al, 2017]. For estimating plant water requirements, surface or canopy temperature (in the case of agricultural crops) is the most accepted and reliable tool [Awais et al, 2022;Peñuelas et al, 1993].…”

Comparative Evaluation of Land Surface Temperature Images from Unmanned Aerial Vehicle and Satellite Observation for Agricultural Areas Using In Situ Data

“…They produced spatial maps by combining the LST, albedo, and superficial thermal inertia to enhance the characteristics of LULC in metropolitan areas and obtain microclimatic data [23]. Different researchers analyzed the LST and soil moisture (SM) content using TIR cameras that were mounted on the unmanned aerial systems [24][25][26],…”

Verification of Accuracy of Unmanned Aerial Vehicle (UAV) Land Surface Temperature Images Using In-Situ Data

“…produced a map that combined LST, albedo, and apparent thermal inertia using a UAV to improve the classification of fine land cover materials and energy balance models in urban areas and to acquire microclimatic information [18]. Kang et al (2018) derived the usability of UAV TIR LSTs in analyzing the thermal environment of urban green areas. As described above, many studies have analyzed LST using TIR cameras mounted on UAVs [21].…”

“…Kang et al (2018) derived the usability of UAV TIR LSTs in analyzing the thermal environment of urban green areas. As described above, many studies have analyzed LST using TIR cameras mounted on UAVs [21]. However, few studies have verified the accuracy of LSTs acquired from UAV TIR cameras through in-situ measurements.…”

“…However, few studies have verified the accuracy of LSTs acquired from UAV TIR cameras through in-situ measurements. Although some studies compared UAV TIR LSTs with in-situ LSTs for several land cover materials using thermal imaging cameras or contact-type surface thermometers [19,[21][22][23], the studies that verified the accuracy of UAV TIR LSTs for various land cover materials distributed in complex urban areas are insufficient. TIR satellite images are used in urban planning to alleviate the UHI by verifying the accuracy of LSTs and correcting them using the measured data [11,[24][25][26][27][28].…”