Regular circulation structures in the tropical basin of Mexico City as a consequence of the urban heat island effect

Cluster Analysis of the Wind Events and Seasonal Wind Circulation Patterns in the Mexico City Region

“…The effect of the general circulation of atmosphere at the horse latitudes and below the Tropic of Cancer (trade winds, Caribbean low level jet, subtropical jet stream of winter, and prevailing westerlies) was also reflected by these patterns, for example, by WP2 and WP5. Agreement with the qualitative wind circulation modes described by Jauregui [5,6], Klaus et al [15,36], Doran et al [9], Doran and Zhong [39], and de Foy et al [16] was found, although our comparison was done with more detail compared to the results from de Foy et al, because no other work where cluster analysis is used to identify the Mexico City wind patterns was found in literature. In the present work, as an important difference with respect to the above mentioned studies, it is stressed that a notably larger wind database was considered in the analysis (a set composed of six years of hourly wind data from a 10 station network) that it was possible to give a detailed and quantitative characterization of the wind circulation patterns in terms of the attributes of the extended wind state concept (u, v, γ, ω), two of which (γ, ω) never were used before for these purposes, and also that an estimation of the probabilities of occurrence of the wind patterns was provided.…”

“…The wind states in this pattern started to develop around hour 18, increasing the cluster population which reached and maintained its highest values from midnight to sunrise, and then suddenly decreased, almost dying around the hour 8 ( Figure 11). Their wind direction states suggest downslope winds from the surrounding mountains, converging towards Mexico City basin due to gravitational effect; however, this pattern is reinforced by the urban heat island effect, as it has been already described by Jauregui [6] and Klaus et al [36].…”

Lattice Wind Description and Characterization of Mexico City Local Wind Events in the 2001–2006 Period

“…This feature favors northerly, northeasterly and southerly wind circulation, driven by synoptic winds and temperature gradients. However, due to the mountain-valley system of Mexico City, drainage winds are also driven systematically, mainly during nighttime and early morning, and frequently reinforced by the urban heat island phenomenon [9,10]. …”

“…In another paper [5], otherwise, we studied the same set of continuous wind states from the standpoint of hierarchical cluster analysis with the purpose of recognizing and characterizing the clusters of wind states that can be considered as instances or cases of the wind circulation patterns that prevailed in the Mexico City region during the period 2001-2006. Description and characterization of the local wind events and the estimation of their occurrence probabilities are important issues for different purposes in several fields of application, such as urban planning, wind resource assessment, and air quality assessment, among others. Increasing urban transformation and expansion change the morphology of a city, and these modifications have to be taken into account in urban planning because they induce mechanical and thermal processes that change the local wind circulation conditions [6], affect the local urban climate [7], and intensify the urban heat island [8][9][10]. During air quality assessment, knowing the wind circulation modes in a city allows one to understand how the emissions of pollutants will be transported and dispersed in the atmosphere [11,12], how these emissions will impact the area near the sources [13], and how to evaluate the possibilities of pollution being transported toward the surrounding urban and rural settlements [14].…”

Modeling urban environmental quality in a tropical city

“…Current satellite sensors are unable to capture all of this complexity due mainly to their spatial and spectral inadequacies; for example, they are unable to detect air quality due to spectral limitations. However, the close positive relationship between this parameter and the Urban heat island (Dwyer et al, 1992;Klaus et al, 1999;Environmental Protection Department, 2001), and its inverse relationship with biomass (Gallo et al, 1993;Weng, 2001), is well documented. Surface temperature derived from thermal satellite images has been used to characterize urban heat islands (Roth et al, 1989;Nichol, 1994) and fine resolution sensors such as IKONOS are able to identify land cover, including biomass, at detailed level (Nichol and Lee, in press).…”