Long term variation of surface horizontal visibility is a clear indicator of atmospheric quality and it does not depend on any measurement device susceptible of lack of calibration. In this paper we present visibility series measured at Ebro Observatory (Spain), in the western part of Mediterranean area. Although these observations being performed in a priori “clean” location, no natural causes can explain the visibility trends and the anthropogenic activity is the most probable cause.

In the early part of the 20th century, tracking a pilot balloon from the ground was one of the few methods that was able to provide information from the upper air. 30 g pilot balloon were used at many meteorological observatories as at Ebro Observatory (Spain) for this purpose. This study presents a new thermodynamic model which allows us to compute the different parameters affecting the ascent rate of these balloons, essential to obtain the meridional and zonal components of the wind profile.

Commercial solutions for an automated DI-flux are practically reduced to the AutoDIF and the GyroDIF. We analyze the pros and cons of both in terms of suitability at the Livingston Island geomagnetic observatory, Antarctica. We conclude that the GyroDIF is more suitable for harsh conditions due to its simpler infrastructure. We also show the instrument housing design and its control electronics. Our experiences can benefit the geomagnetic community, which often faces similar challenges.