The dataset consists of a 39-year long directional wave time series recorded since 1979 at the CNR-ISMAR "Acqua Alta" oceanographic research tower (AAOT), located in the Northern Adriatic Sea. The extent of the time series allows to describe the wave climate in the North Adriatic region and to identify trends and links with large scale climate patterns from a single and permanent observational source.The northern part of the Adriatic Sea is characterized by two main wind and correspondingly wave regimes, strongly forced by the regional orography. The high sensitivity of this particular area to even small variations of large scale meteorological patterns allows to explore possible links of the local wave, hence wind, activity with large-scale north hemisphere circulation or weather regimes.Different wave gauges have been used since the start of the measurements, progressively upgraded and repositioned during maintenance operations. The recorded wave data have been thoroughly verified and corrected where necessary.

Issues related to lack of homogeneity in the original recorded time series are discussed in the related Data Descriptor published on Scientific Data: Pomaro, A., Cavaleri, L., Papa, A. & Lionello, P., 39 years of directional wave recorded data and relative problems, climatological implications and use. Scientific Data (2018). In particular the second period (1987-2003) of the overall record has required a specific analysis and it has been partially corrected taking into account an original error in the position of one of the transducers. The methods leading to a corrected time-series are fully described in the cited publication. This may need to be considered for certain specific uses of the timeseries.

Supplement to: Pomaro, Angela; Cavaleri, Luigi; Papa, Alvise; Lionello, Piero (2018): 39 years of directional wave recorded data and relative problems, climatological implications and use. Scientific Data, 5, 180139