Ocean Bottom Pressure Variability: Can It Be Reliably Modeled?

• Published in: Journal of Geophysical Research: Oceans
• Main Authors: Androsov, Alexey, Boebel, Olaf, Schröter, Jens, Danilov, Sergey, Macrander, Andreas, Ivanciu, Ioana
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2020
• Subjects: Southern Ocean
• Online Access: https://epic.awi.de/id/eprint/51364/; https://hdl.handle.net/10013/epic.438a50b1-c742-4969-8fd6-6997108396aa

Ocean bottom pressure (OBP) variability serves as a proxy of ocean mass variability, the knowledge of which is needed in geophysical applications. The question of how well it can be modeled by the present general ocean circulation models on time scales in excess of one day is addressed here by comparing the simulated OBP variability with the observed one. To this end, a new multi-year data set is used, obtained with an array of bottom pressure gauges deployed deeply along a transect across the Southern Ocean. We present a brief description of OBP data and show large scale correlations over several thousand kilometres at all time scales red using daily and monthly averaged data. Annual and semi-annual cycles are weak. Close to the Agulhas Retroflection, signals of up to 30 cm equivalent water height (EWH) are detected. Further south, signals are mostly intermittent and noisy. It is shown that the models simulate consistent patterns of bottom pressure variability on monthly and longer scales except for areas with high mesoscale eddy activity, where high resolution is needed to capture the variability due to eddies. Furthermore, despite good agreement in the amplitude of variability, the in situ and simulated OBP show almost no correlation.