Decadal Variation of the Land Surface Temperatures (LST) and Urban Heat Island (UHI) over Kolkata City Projected Using MODIS and ERA-Interim DataSets

2020 ◽  
Vol 4 (3) ◽  
pp. 200-209
Author(s):  
Priyanko Das ◽  
K. Sandeep Vamsi ◽  
Zhang Zhenke
2021 ◽  
Vol 13 (22) ◽  
pp. 12678
Author(s):  
Dakota McCarty ◽  
Jaekyung Lee ◽  
Hyun Woo Kim

The urban heat island effect has been studied extensively by many researchers around the world with the process of urbanization coming about as one of the major culprits of the increasing urban land surface temperatures. Over the past 20 years, the city of Dallas, Texas, has consistently been one of the fastest growing cities in the United States and has faced rapid urbanization and great amounts of urban sprawl, leading to an increase in built-up surface area. In this study, we utilize Landsat 8 satellite images, Geographic Information System (GIS) technologies, land use/land cover (LULC) data, and a state-of-the-art methodology combining machine learning algorithms (eXtreme Gradient Boosted models, or XGBoost) and a modern game theoretic-based approach (Shapley Additive exPlanation, or SHAP values) to investigate how different land use/land cover classifications impact the land surface temperature and park cooling effects in the city of Dallas. We conclude that green spaces, residential, and commercial/office spaces have the largest impacts on Land Surface Temperatures (LST) as well as the Park’s Cooling Intensity (PCI). Additionally, we have found that the extent and direction of influence of these categories depends heavily on the surrounding area. By using SHAP values we can describe these interactions in greater detail than previous studies. These results will provide an important reference for future urban and park placement planning to minimize the urban heat island effect, especially in sprawling cities.


Author(s):  
K. P. Landicho ◽  
A. C. Blanco

Abstract. Unprecedented urbanization in Metro Manila has led to the proliferation of the urban heat island (UHI) effect. This is characterized by a prominent difference in the temperatures of the urban and its surrounding rural and less urbanized areas. Temperature differences occur within these UHI’s indicating the existence of intra-urban heat islands (IUHI). UHI’s and IUHI’s are well-documented indicators of urban environmental degradation and therefore puts the population of Metro Manila at risk. In anticipation of these effects, their detection and the characterization of their behaviour through time can contribute to proper urban planning thus mitigating harmful effects. Google Earth Engine was used to retrieve land surface temperatures (LST) from Landsat data from 1997 to 2019 using emissivity estimation. The Local Moran’s I statistic was then used to identify cluster and outlier types (COT). A histogram with 10 bins representing the net COT frequencies per barangay was then used to identify IUHI’s. Annual temperature measurements and COT areas were plotted against time and based on linear-fit trend lines they characterize the study area as to having an annual increase in temperature of roughly 0.18 °C and hotspot area extent of around 0.03 km2, and a decrease in coldspot area extent around 0.01 km2. Hotspots were found to be frequent in the cities of Caloocan, Manila, Pasay, and Quezon while coldspots were found to be frequent in the cities of Caloocan, Las Piñas, Malabon, Navotas, and Valenzuela. In conclusion, IUHI’s were detected with statistical basis, both spatially and temporally.


2021 ◽  
Vol 13 (3) ◽  
pp. 1099
Author(s):  
Yuhe Ma ◽  
Mudan Zhao ◽  
Jianbo Li ◽  
Jian Wang ◽  
Lifa Hu

One of the climate problems caused by rapid urbanization is the urban heat island effect, which directly threatens the human survival environment. In general, some land cover types, such as vegetation and water, are generally considered to alleviate the urban heat island effect, because these landscapes can significantly reduce the temperature of the surrounding environment, known as the cold island effect. However, this phenomenon varies over different geographical locations, climates, and other environmental factors. Therefore, how to reasonably configure these land cover types with the cooling effect from the perspective of urban planning is a great challenge, and it is necessary to find the regularity of this effect by designing experiments in more cities. In this study, land cover (LC) classification and land surface temperature (LST) of Xi’an, Xianyang and its surrounding areas were obtained by Landsat-8 images. The land types with cooling effect were identified and their ideal configuration was discussed through grid analysis, distance analysis, landscape index analysis and correlation analysis. The results showed that an obvious cooling effect occurred in both woodland and water at different spatial scales. The cooling distance of woodland is 330 m, much more than that of water (180 m), but the land surface temperature around water decreased more than that around the woodland within the cooling distance. In the specific urban planning cases, woodland can be designed with a complex shape, high tree planting density and large planting areas while water bodies with large patch areas to cool the densely built-up areas. The results of this study have utility for researchers, urban planners and urban designers seeking how to efficiently and reasonably rearrange landscapes with cooling effect and in urban land design, which is of great significance to improve urban heat island problem.


Author(s):  
A. Tahooni ◽  
A. A. Kakroodi

Abstract. Urban Heat Island (UHI) refers to the development of higher urban temperatures of an urban area compared to the temperatures of surrounding suburban and rural areas. Highly reflective urban materials to solar radiation present a significantly lower surface temperature and contribute to reducing the sensible heat released in the atmosphere and mitigating the urban heat island. Many studies of the UHI effect have been based on Land Surface Temperature (LST) measurements from remote sensors. The remotely sensed UHI has been termed the surface urban heat island (SUHI) effect. This study examines Tabriz city land use/land cover (LULC) and LST changes using Landsat satellite images between 2000 and 2017. Maximum likelihood classification and single channel methods were used for LULC classification and LST retrieval respectively. Results show that impervious surface has increased 13.79% and bare soil area has decreased 16.2%. The results also revealed bare soil class LST after a constant trend become increasing. It also revealed the impervious surface LST has a decreasing trend between 2000 and 2011 and has a little change. Using materials that have low absorption and high reflectance decrease the effect of heat island considerably.


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