Since 1988 the regular summer hydrographic observations in the Nordic Seas and Fram Strait have been collected by the Institute of Oceanology Polish Academy of Sciences (IOPAS). Observational activities were carried out under several national programs, in the frames of EU projects VEINS, ASOF-N and DAMOCLES and within Polish-Norwegian cooperation in the AWAKE project. The main objectives are: to study the long-term variability of water mass distribution, their physical and chemical properties and different pathways in the Nordic Seas; to investigate the Atlantic water (AW) circulation in the Nordic Seas and its inflow into the Arctic Ocean; to recognize the possible feedbacks between the Atlantic water variability and local and global climate changes.