Letter from the Editor

In this anniversary issue of Atmósfera we include an excellent revision of the literature on chlorine in the stratosphere prepared by Thomas von Clarmann, who is a senior researcher and head of the Satellite-Borne Remote Sensing of Trace Gases group at the Karlsruhe Institute of Technology. In his review, Dr. von Clarmann describes with clarity not only the complex processes involved in the destruction of stratospheric ozone by chlorinated compounds, but also analyzes the chronological events leading to this paradigmatic discovery. The author shares with us his view of how the knowledge increased and emphasizes the usefulness of remote sensing techniques for detecting and monitoring many of the key species involved in stratospheric chemistry. We are very grateful with Dr. von Clarmann for accepting the invitation from the Editorial Board for contributing with this anniversary article, and with our associate editor Michel Grutter for his involvement in this manuscript.

Our regular articles for this issue cover a variety of topics: F. J. Paredes et al. develop and validate a probabilistic model to predict the occurrence of meteorological droughts in Venezuela; R. Vargas et al. outline the conceptual and technical framework for the establishment of a regional network based on the eddy covariance method (the MexFlux network) to measure the surface-atmosphere exchange ofheat and greenhouse gases in Mexico; D. López-Hernández et al. describe the changes in the chemistry of acid rains loaded with pollutants—which are characteristic of northern central Venezuela as a consequence of high industrial and agricultural activities—after passing through a sugar cane canopy; F. López-Díaz et al. use extreme climate indices for the period 1952-2003 to analyze variations in extreme temperature events in the municipality of Apizaco,Tlaxcala, as a contribution to the knowledge of extreme climate events in Mexico; S. Verma et al. discuss the temporal and spatial variations in aerosols and aerosol forcing during the winter monsoon season (January-March) for the Indian Ocean Experiment first field phase in 1998 and intensive field phase in 1999; C. Ponce Caballero et al. establish the seasonal variation of fungal propagules in homes of Mérida, Yucatán, Mexico, and examine the relation between their concentrations in enclosed and open locations taking into account environmental parameters such as temperature, humidity and wind speed; Y. Skiba and D. Parra-Guevara use the advection-diffusion equation to describe the dispersion of pollutants in a limited area, and suggest methods based on the control of emission rates of sources for preventing dangerous levels of pollutants in ecologically important zones; finally C. Rivera et al. use satellite data in conjunction with ground-based measurements to construct temporally-resolved maps of nitrogen dioxide over central Mexico, in order to identify main sources of anthropogenic pollution and typical transport pathways.

Also, I would like to note that in this issue we introduce an important change in the appearance of our journal: We shifted from a one-column to a two-column format. The editorial team expects this modification will make the reading of Atmósfera a more pleasant activity.

Sincerely,

Carlos Gay
Chief Editor