Luis F. Pineda-Martínez

Dispersion of atmospheric coarse particulate matter in the San Luis Potosí, Mexico, urban area

Atmospheric pollution in urban areas of Mexico has become a serious problem. The study of spatio-temporal evolution of concentrations of particulate matter is an important issue. A total of 188 samples were randomly collected at 24-hour running time within the period from May 2003 to April 2004 for the San Luis Potosi urban area, located in the central-north part of Mexico, using quartz fiber filters. A series of numerical modeling experiments were conducted for the same period of measurements to investigate particulate matter (PM) concentrations in the above-mentioned urban area. Although there is a considerable annual variability in the atmospheric circulation, the analysis of results indicates preferential seasonal circulation patterns: southwesterly winds during winter and southeasterly during summer. High concentration values of particulate matter were closely associated to local characteristics of the atmospheric circulation. A net transport from the industrial zone into the urban area is one of most important outcomes of the investigation.

Air Quality Deterioration of Urban Areas Caused by Wildfires in a Natural Reservoir Forest of Mexico

Many regions of the world suffer loss of vegetation and reduced air quality due to wildfires. Studies on aerosol emissions by wildfires often discuss the negative effects of atmospheric contaminants from a regional or mesoscale perspective. The occurrence of wildfires reveals that a high percentage takes place close to large urban areas. Very high concentration of pollutants and PM10 particulate matter reach urban zones and millions of inhabitants. These events of high pollutant concentrations are seasonally recurrent. There are many large urban areas in the world that often undergo severe air deterioration due to wildfires smoke. We document the extreme impact of wildfire that occurs in the Protected Area of Flora and Fauna La Primavera located in neighborhood of Guadalajara, a large urban zone in Mexico. The simultaneous emissions of aerosols by 60 wildfires were simulated and compared with observed data. The plume generated by the wildfires reached large areas of the central part of Mexico. The principal characteristics of smog emissions (CO, NO2, and PM10) over the urban area were acceptably reproduced. Observed and modeled CO, PM10, and NO2 data indicated that aerosol plumes generated by the wildfires increased notably the concentrations over the metropolitan zone of Guadalajara.

Climatic analysis linked to land vegetation cover of Mexico by applying multivariate statistical and clustering analysis

The climate regions of Mexico are delimitated using hierarchical clustering analysis (HCA). The data used consists of monthly means of maximum and minimum temperatures and monthly-accumulated precipitation. The dataset was obtained from heterogeneously distributed climatic stations in Mexico for the period from 1961 to 2004. This cluster method assigns precipitation and temperature variables to groups of clusters based on similar statistical characteristics. We carried out a principal components analysis to obtain a standardized reduced matrix to be used in HCA. By applying two clustering criteria (K-means and Ward´s method) it was possible to define statistically groups of stations that delimit regions of similar climate. In addition, the applied methodology describes the dominant vegetation distribution for each climate region. This analysis may contribute to the generation of new climate scenarios, where the dynamics of land vegetation cover could be included as a biomarker of climate.

Implications of maximum daily precipitation on streamflow of a watershed: a case study in Zacatecas, Mexico

ABSTRACT In this article, we present the results of the analysis of a flood event that occurred on 18 July 2008 in the town of Tlaltenango, Zacatecas, Mexico. The flood was caused by a storm that reached an accumulated precipitation of 145 mm/day. The event was caused by the passage of hurricane Fausto that produced an intensification of moisture transport to the mainland channelled by topography. The storm event was simulated using the Mesoscale Model version 5 (MM5). The hydrologic model Hydrologic Engineering Center (HEC)-1 was then employed to determine the run-off hydrographs and streamflows. Finally, the Hydrologic Engineering Centers River Analysis System (HEC-RAS) model predicted water levels by integrating information about channel geometry and characteristics such as roughness. The numerical results show that the map of the flooded area as simulated by the HEC-RAS model matches the observed inundation extent for this event well. The calculated values for water levels were quite similar to those directly recorded by civil protection authorities in the urban area. Despite the recent history of recurring flood events, plans and strategies have not been implemented to reduce flooding.