Bioclimatic conditions in Mexico City - an assessment

Abstract

Bioclimatic conditions have been assessed for a large urban area located in the tropical highlands of central Mexico using the indices (in °C) of resultant temperature (RT) and effective temperature (ET). The welldeveloped heat island effect the city generates, reduces the number of nights categorized as cold (ET between 5 and 15° C) to cool (ET from 15 to 18.5° C). Most days fall in the cold to cool range and during the warm season (April to June) the bioclimate of Mexico City is mostly within the neutral (comfort) range. The effect of the nocturnal (to the west) and daytime (to the east of the town) heat island is noticeable in the central and northern sectors. The daytime heat island located in these regions, albeit small (urban air temperature 2-3° C greater than rural), compared with the nocturnal heat island intensity (9-10° C) still adds energy to the already heated afternoon urban air. ET values in the north and central sectors approach the threshold for comfort (ET of 25° C) during the warm months around noon. It is not surprising to find that as the nocturnal heat island has increased over the years as the city grew, so has the ET for the central district and indicating the dominating role of temperature in the ET index. Assessment of the diurnal cycle of bioclimatic conditions in downtown Mexico City by means of two empirical indices (effective temperature and thermopreferendum) throughout the years gave similar results to those obtained from the application of Fanger's predicted mean vote (PMV) model. An attempt has been made to characterize four bioclimatic zones in the capital city.

Short-term effects of temperature-related indices on emergency ambulance dispatches due to mental and behavioral disorders in Shenzhen, China

“…Our study incorporated 10 commonly used temperature-related indices to examine the associations between meteorological factors and MBDs. Supplementary Table S1 presents a detailed description of these indices, including the daily mean, minimum, and maximum temperature (Tmean, Tmin, and Tmax), apparent temperature (AT) (23), Rothfusz's heat index (RHI) (24), wind chill index (WCI) (25), effective temperature (ET) (26), net effective temperature (NET) (25), humidity index (Humidex) (27), and alternative temperaturehumidity index (THIa) (28).…”

The impact of urban compactness, comfort strategies and energy consumption on tropical urban heat island intensity: A review

“…Apart from the effect on energy consumption, tropical UHIs also lead to thermal discomfort, morbidity and perhaps even mortality. Evidence for long-term (1921 -1985) change in bioclimatic conditions in cities due to the UHI phenomenon was first reported in the sub-tropical Mexico City nearly 20 years ago (Jauregui et al, 1997). Yan (1997) has shown a rise in mortality and morbidity in high density compact cities due to heat related stress.…”

Applied climatology

“…Adjustments can therefore be made in response to the likely impacts of such factors as airflow and shade. The implications of the urban heat-island effect for bioclimatic conditions and human comfort have been assessed for Mexico City by Jauregui et al (1997). This approach provides the basis for urban bioclimatic design as has been investigated for the arid zone of Argentina (Papparelli et al 1996), where appropriate responses were outlined allowing for seasonal climate variability.…”