FINDINGS ON THE ATMOSPHERIC HUMIDITY BALANCE OVER EUROPE ON THE BASIS OF AEROLOGICAL MEASUREMENTS
L. NYITRAI, R. TÓTH
ABSTRACT. – Findings on the atmospheric humidity balance over Europe on the basis of aerological measurements. There are countries suffering water shortages in all continents and lack of water can be potential cause of political conflicts in the near future. The Water Summit organised in Budapest both in 2013 and 2016 tried to promote the effective and sustainable water management and sanitation. On this occasion we want to give an overview on changes in the humidity climate of the atmosphere over Europe in the last four decades. An imaginary screen, a vertical wall was drawn around Europe and we examined how much moisture flux passed through it. We focused on the relative change of that parameter paying attention also to other variables of climate change, especially the temperature. We surround the central core of our continent – that is most exposed to drought – as a possible closed curve by a series of upper air stations, e.g.: Lerwick (UK), Brest (FR), Santiago de Compostella and Madrid (ES), Ajaccio (FR), Milan (IT), Thessaloniki (GR), Istanbul (TR), Bucharest (RO), Odessa (UA), Leba (PL), Schlezwig (GE). We want to know to what extent the changes in detected moisture level could be caused by the changes in evaporation pattern over the oceans playing decisive role in the atmospheric moisture content. There is a simplistic concept that, if the sea surface warms, it can grow the evaporation and so the water content in the atmosphere, which reduces rainfall deficit over the lands as a result of the general atmospheric circulation. But this is not such a simple process, because the stability of the vertical structure of the atmosphere over the seas that are predominantly involved in the moisture emission is important fact. On the other hand changes in wind that is the horizontal transport should be taken into account. First we expected the stability over the seas to increase and for this reason there is a lack of precipitation on a global scale. Contrarily, the measurements indicate that rather just decrease in stability occurred in the vicinity of sea stations, which in turn increases the number and extent of unstable atmospheric condition leading to showers and thunderstorms. We face the difficult task of measurement or estimation of the precipitation falling into the seas. In case of increase in this rainfall the precipitation falling over the continent should be reduced.
Keywords: upper-air, sounding measurement, moisture transport, humidity balance.