Extending the official climatological analysis of the wind velocity data in Malta

Abstract

It is well known that short-term wind measurements do not capture the climatological variability of wind speeds at a site. Joining short-term measurements with a historical data set should facilitate the projection of climatological wind characteristics. This study focuses on trends and variations of monthly mean wind speed in Malta by rescuing and making use of historical raw data charts. This data spans from 1949–1964 and the site of collection was the University of Malta, Valletta campus. Additional data spanning from 1965-2010 was obtained from the Luqa Airport MET office for comparative purposes. These two data sets were combined together to note any statistical correlation. The Mann Kendall's test results indicate a positive non statistically significant trend from 1949-1964 compared to a significant negative trend between 1965-2010 (Galdies, 2011). Results indicate a bias between the average wind speed measured during 1949-1964 with that of the 1965-2010 data set. The analyses presented identify possible explanations for this bias including aspects such as the station's relocation, anemometer height changes, malfunctions and changes in the instrumentation, observation gaps, data digitization and processing procedures.