RAMA2GrADS

Introduction

Air quality and meteorological observation data is commnly measured and available, one way to study and analize it is by visualization it in a map. In the case of Mexico City the Integral Air Quality Monitorig System (SIMAT) collects data since 1986 up to now, the data is in an ascii comma separated values (CSV) format and the location of the stations is also available. The Grid Analisis and Display System (GrADS) is an interactive desktop tool capable to display station data and model result. in order to use the larga data set of measurements it is necesary to convert the station database in format useful for the GrADS. This convertion from SIMAT data base to in made by this system.

Code Description

The conversion system uses the station locations and data from different files, after maching the location with the measured vairalbe it is written to a binary file following the format requiered for station GrADS format.

The RAMA2GrADS system contains functions and subroutines to acomplish this task. The subroutine lee_simat_dat loads the measured data, int this case meteorological data and pollutnat data are in different files . lee_estaciones_rama subroutine reads the stations locations. In the output subroutine it is located the code to write surface station data.

Usage

The RAMA2GrADS system requieres a configuration file for setting the time period and names for the meteorological and pollutant files. This is obtained by setting the variables in the namelis.nml file

 &FECHA
 anio=2011
 imes=01
 fmes=12
 idia=01
 fdia=31
 met_file="meteorologia_2011.csv"
 pol_file="contaminantes_2011.csv"
 /

• anio year of the data.
• imes starting moth for storing the data.
• fmes end month.
• idia starting day for storing the data
• fdia ending day
• met_file meteorolgical data with SIMAT format
• pol_file contains the pollutant measured data with SIMAT format

The files met and pol contain 11 header lines with the following format:

01/01/2011 01:00,ACO,RH,,6
01/01/2011 01:00,MON,RH,38,6
01/01/2011 01:00,CHO,RH,,6)

the est_rama.txt stations file has one header with the following format:

Alias   Latitud    Longitud  Altitud  Estacion description
ACO    19.635501  -98.912003  2198    Acolman
AJM    19.2721    -99.207658  2619    Ajusco Medio
HGM   19.411617   -99.152207  2234    Hospital General de M<8E>xico

output

Thhe code generated two files one with the binary data file and the descriptor file (ctl)

References

Grid Analysis and Display System (Grads) [Creating a Station Data File] (http://cola.gmu.edu/grads/gadoc/gadocindex.html)

Mexico Air quality Network [SIMAT] (http://www.aire.cdmx.gob.mx/default.php)