Determinación del índice de estrés térmico WBGT

The heat stress index WBGT (wet bulb globe temperature) during the European Athletics Championships Marathon in Barcelona July 31 and August 1, were studied because of the importance of this index is because it includes the most variables in meteorological dates.

The way to calculate this index in the common meteorological stations in an empirical and also in an approximate form, is described in the first part of this work . So that, are also neccessary the measurements of the parameters: the environment temperature, the wet thermometer temperature as well as the relative humidity. We also have to measure the wind velocity, the global and diffuse radiation and the sun angle. Obviously, the sunny hour and the longitude and latitude of the place where dates were collected. Once the dated are gathered, is possible to calculate the index because WBGT= 0.7 t_N + 0,2 t_g + 0,1 t (Minard, 1961). On the other hand, if we split t_N, as suggest Hunter and Minyard (1999) it results WBGT = 0.7t' + 0.00147S - 0.294u +0.2t_g + 0.1t +1.351, being t the environment temperature, t_g the temperature of the black globe and t' wet thermometer temperature, S the sunny radiation and u the wind.

In the second part, the dates of women and men marathon in two different places of the circuit are collected and compared to establish the differences among them.

Once obtained the dates, is possible to conclude that in both marathons it exceeded the limits suggested for this activity. Overall, we must realise that in not any minute the recomended levels for safety area as well as moderate dangerous area werw always exceded. The temperature, was always being among high degrees (23-28º) and extreme degrees (28-30º). On the other hand the dates obtained are not concomitant in both points.

Comparing the variables can be stablish the fact that in those days the index arised almost the expression WBGT = 0,2 tg +18. And using the expression purpossed by Turco et al. (2010), using the dates of global radiation in the Physics Faculty, we can conclude that differences among them would be less to 3º.

The variations between both stations are discussed in the present work, although the most important variations found were because of the cloudy changes.