Cruise Report, RV ATAIR, Cruise 067I033-1, Bremerhaven – Thybor?n – Aberdeen, 23 Jul – 15 Aug 2024 7 The particular cruise 067I033-1 of summer 2024 consisted of two legs, with leg 1 covering the southern to central part of the North Sea and leg 2 covering the central to northern part of the North Sea. Leg 1 with departure in Bremerhaven, Germany, on 23 July led to the port of Thy- bor?n, Denmark, where the vessel arrived on 4 August (compare Figure 1.1). The port stay during 4 and 8 August was used to exchange crew members and scientific participants (see Section 2). Due to a necessary repair of the vessel’s X-band radar, the subsequent departure was delayed. The cruise was resumed on 8 August, when the vessel departed from Thybor?n in order to pursue leg 2 of cruise 067I033-1 in the northern part of the North Sea, which ended with the vessel arriving in Aberdeen, UK, on 15 August 2024. Similar to summer 2023, the spatial resolution of the northern sections of cruise 067I033-1 was increased in summer 2024 in order to resolve smaller scale oceanic structures. Furthermore, two survey lines located to the west and east of the Orkney and Shetland Islands covering the inflow of Atlantic Water into the North Sea were planned. The major purpose of cruise 067I033-1 based on respective measurement was to assess the state of the North Sea in summer 2024 with focus on the physical and chemical state. Respec- tive large-scale data will contribute to investigating the hydrographic state of the water column in different regions of the North Sea. Furthermore, temporal hydrographic changes as they become obvious when bringing the data into context with data from previous cruises shall be addressed. Particular objectives related to cruise 067I033-1 are the following: ? How far does the Atlantic Water (AW) that enters the North Sea at its northern limits propagate southward in summer 2024? ? Where does the main inflow take place? ? How far does AW entering the southern North Sea via the English Channel penetrate northwards in summer 2024? ? What is the respective regional sharpness and depth of the thermocline? ? What is the total salt and heat content of the North Sea in summer 2024? ? Where is the Baltic outflow located? ? What is the current distribution of trace metals and microplastics in the North Sea? ? What are major input pathways of mercury (Hg) to the North Sea, and how do Hg species vary within the North Sea? ? What is the state of the carbon system in summer 2024? ? What is the present-day concentration of the radionuclide tritium in the North Sea? ? What are typical drifter pathways at the sea surface, and what are the associated spreading time scales? Overarching objectives that address temporal changes on different time scales are: ? How do changes in the Northeast Atlantic happening on time scales ranging from seasonal to decadal affect the North Sea?