Future scenarios of thermal bioclimatic conditions in a humid tropical city under urban development

Abstract Urbanization modifies the heat balance in urban areas and has negative effects on landscape, aesthetics, energy efficiency, human health and the inhabitants’ quality of life. This work evaluated future scenarios of bioclimatic conditions for João Pessoa, a humid tropical city in Northeast Brazil. The scenarios were determined based on trends in air temperature, relative humidity and wind speed for the time period from 1968 to 2015. The study was performed for two distinct periods of three months each (dry and wet seasons) using data from weather stations equipped with thermo-hygrometers and cup anemometers located in nine representative areas of the city. Trends in air temperature, relative humidity, wind speed, and effective temperature index (ET index) time series were evaluated using the Mann-Kendall test. Results indicated that the air temperature showed an increasing trend of 0.34°C /decade, whereas the relative humidity showed a decreasing trend of 0.49%/decade and the wind speed values ranged from 1.3 ms-1 to 3.80 ms-1. These trends are statistically significant according to the Mann-Kendall test (p<0.05). The air temperature increased between the 1980s and 2010s, which corresponds to a period of rapid urbanization of the city. Future environmental conditions in João Pessoa will be determined in accordance with the urbanization processes.

摘要：城市化改变了城市区域的热平衡，对景观、美学、能源效率、人类健康以及居民生活质量均产生负面影响。本研究针对巴西东北部湿润热带城市若昂佩索阿（João Pessoa）的生物气候条件未来情景展开评估。该情景基于1968年至2015年期间的气温、相对湿度及风速趋势确定。研究针对两个各为期三个月的典型时段（旱季与湿季）开展，所用数据来自分布于该市9个代表性区域的气象站点，这些站点均配备温湿度计（thermo-hygrometers）与杯式风速仪（cup anemometers）。采用曼-肯德尔检验（Mann-Kendall test）对气温、相对湿度、风速以及有效温度指数（ET index）的时间序列趋势进行分析。结果显示，气温以每十年0.34℃的速率呈上升趋势，相对湿度则以每十年0.49%的速率呈下降趋势，风速取值范围为1.3 m·s⁻¹至3.80 m·s⁻¹。经曼-肯德尔检验验证，上述趋势均具有统计学显著性（p<0.05）。1980年代至2010年代期间，该市气温呈上升态势，这一时期恰好对应该市快速城市化阶段。若昂佩索阿未来的环境条件将由城市化进程决定。