Thermal properties based on air temperature observations in different local climate zones in Bogotá, Colombia

2020 ◽  
Vol 82 ◽  
pp. 15-31
Author(s):  
EA Ramírez-Aguilar ◽  
LCL Souza

This paper demonstrates an early application of local climate zones (LCZs) in the city of Bogotá, Colombia. The main goal was to assess the thermal properties within the areas of influence (sectors) of 10 meteorological stations in the city, classified into the LCZ scheme. Air temperature observations at 07:00, 13:00 and 19:00 h (T7:00, T13:00 and T19:00) and daily measurements were obtained from the stations, and the maximum (Tmax), minimum (Tmin) and mean (Tmean) values were calculated. Their distribution and variation were analyzed, thermal sensation categories were calculated, and the thermal differences (ΔTLCZX-LCZD) between open-compact LCZ types and LCZD (typical rural type with low plants) were obtained in order to identify patterns between the stations and their assigned LCZs. Furthermore, we compared urban morphology (form) parameters to the ranges proposed in the literature to classify LCZs. The results clearly showed variations and patterns between the stations and their assigned LCZs when using Tmin, T7:00 and T19:00 air temperature data and the indices and categories calculated from these. Values of ΔTLCZX-LCZD > 5°C were found in the densely urbanised LCZ at night, and some negative values at noon suggested the presence of an urban cool island. The results show the usefulness of LCZs in understanding differences and temperature variations between divergent urban sectors. However, when different LCZ types are grouped, the thermal differences between them can be better appreciated and explained. The main conclusion is that the urban surface of Bogotá does not generate high temperatures, but decreases the occurrences of low values in Tmin, Tmean, T19:00 and T7:00.

Author(s):  
Lindita Bande ◽  
Prajowal Manandhar ◽  
Prashanth Marpu ◽  
Mohammad Al Battah

2019 ◽  
Vol 12 (1) ◽  
pp. 156 ◽  
Author(s):  
Prajowal Manandhar ◽  
Lindita Bande ◽  
Alexandros Tsoupos ◽  
Prashanth Reddy Marpu ◽  
Peter Armstrong

In many cities that have experienced rapid growth like Abu Dhabi, urban microclimate scenarios evolve rapidly as well and it is important to study the urban thermal dynamics continuously. The Local Climate Zone (LCZ) classification considers factors related to the physical properties like surface cover and surface structure of the city which allow to analyze urban heat flows. Abu Dhabi city is rapidly expanding and is characterized by highly heterogeneous types of built forms that comprise mainly of old mid-rise and modern high-rise buildings with varied degrees of vegetation cover in different parts of the city. The fact that it is a coastal city in a desert environment makes it quite unique. This paper presents an approach of studying urban heat flows in such heterogeneous setup. First, the city is classified into local climate zones using images acquired by Landsat Satellite. Numerical simulations are performed in the designated LCZs using a computational fluid dynamics software, Envi-met. The results of Envi-met are calibrated and validated using in-situ measurements across all four seasons. The calibrated models are then applied to study entire Abu Dhabi island across different seasons. The results indicate a clear presence of urban heat island (UHI) effect when averaged over the full day which is varying in different zones. The zones with high vegetation do not show large average UHI effect whereas the effect is significant in densely built zones. The study also validates previous observations on the inversion of UHI effect during the day and in terms of diurnal response.


2021 ◽  
Author(s):  
Ines langer ◽  
Alexander Pasternack ◽  
Uwe Ulbrich ◽  
Henning Rust

<p>Surface (2 m) temperature and specific humidity data are measured at 5-minute intervals in a network comprising 33 stations distributed across the city of Berlin, Germany. These data are utilized in order to validate a LES (large eddy simulation) model designed to assess the local climate at a very high resolution of 10 m to 1 m. This model, was developed at the ​Institute of Meteorology and Climatology (IMUK) of the Leibniz Universität Hannover, Germany, and is developed into an application tool for city planners within the funding programme "[UC²] - Urban Climate under Change", of the German Federal Ministry of Education and Research (BMBF).</p><p>The evaluation distinguishes between the different Local climate zones (LCZ) in the city, which are defined following the concept of Stewart & Oke (2012). For Berlin, the following LCZ have been identified: 2 (compact midrise), 4 (open high-rise), 6 (open low-rise), 8 (large low-rise), A (dense trees), B (scattered trees), D (low Plants), G (water).</p><p>We analyzed one cold winter day during an intensive observation period from 06 UTC on 17<sup>th</sup> January to 06 UTC on 18<sup>th</sup> January, 2017. The minimum and maximum recorded temperatures were -8.1 °C and +2 °C, respectively, the sun shine duration was 6.5 hours. Daily and hourly mean absolute error, mean square error and root mean square error confirm that the deviation between measurements and the PALM-4U model differs between the LCZ for Berlin, with particularly large negative deviations of up to 5 K in forest areas, as they are not yet well represented in the model. Smallest deviations are found for the industrial zone. In all cases, the observed amplitude of the diurnal cycle is underestimated. The role of the driving model for the deviations found is addressed.</p><p>Stewart, I.D., Oke, T.R. (2012) Local climate zones for urban temperature studies. Bull. Amer. Meteor. Soc. 93 1879-1900. DOI: 10.1175/BAMS-D-11-00019.1.</p><p> </p>


Urban Climate ◽  
2018 ◽  
Vol 25 ◽  
pp. 152-166 ◽  
Author(s):  
Christoph Beck ◽  
Annette Straub ◽  
Susanne Breitner ◽  
Josef Cyrys ◽  
Andreas Philipp ◽  
...  

2013 ◽  
Vol 17 (3) ◽  
pp. 60-68 ◽  
Author(s):  
Stevan Savic ◽  
Dragan Milosevic ◽  
Lazar Lazic ◽  
Vladimir Markovic ◽  
Daniela Arsenovic ◽  
...  

2020 ◽  
Vol 15 (5) ◽  
pp. 751-760
Author(s):  
Lindita Bande ◽  
Prajowal Manandhar ◽  
Raghad Ghazal ◽  
Prashanth Marpu

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