A comparison of model and GRACE estimates of the large-scale seasonal cycle in ocean bottom pressure

Abstract. The Atlantic Meridional Overturning Circulation (AMOC) is a key mechanism for large-scale northward heat transport and thus plays an important role for global climate. Relatively warm water is transported northward in the upper layers of the North Atlantic Ocean and, after cooling at subpolar latitudes, sinks down and is transported back south in the deeper limb of the AMOC. The utility of in situ ocean bottom pressure (OBP) observations to infer AMOC changes at single latitudes has been characterized in the recent literature using output from ocean models. We extend the analysis and examine the utility of space-based observations of time-variable gravity and the inversion for ocean bottom pressure to monitor AMOC changes and variability between 20 and 60° N. Consistent with previous results, we find a strong correlation between the AMOC signal and OBP variations, mainly along the western slope of the Atlantic Basin. We then use synthetic OBP data – smoothed and filtered to resemble the resolution of the GRACE (Gravity Recovery and Climate Experiment) gravity mission, but without errors – and reconstruct geostrophic AMOC transport. Due to the coarse resolution of GRACE-like OBP fields, we find that leakage of signal across the step slopes of the ocean basin is a significant challenge at certain latitudes. Transport signal rms is of a similar order of magnitude as error rms for the reconstructed time series. However, the interannual AMOC anomaly time series can be recovered from 20 years of monthly GRACE-like OBP fields with errors less than 1 sverdrup in many locations.

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A window on the deep ocean: The special value of ocean bottom pressure for monitoring the large-scale, deep-ocean circulation

Progress In Oceanography ◽

10.1016/j.pocean.2018.01.011 ◽

2018 ◽

Vol 161 ◽

pp. 19-46 ◽

Cited By ~ 18

Author(s):

Chris W. Hughes ◽

Joanne Williams ◽

Adam Blaker ◽

Andrew Coward ◽

Vladimir Stepanov

Keyword(s):

Ocean Circulation ◽

Large Scale ◽

Deep Ocean ◽

Ocean Bottom ◽

Bottom Pressure ◽

Ocean Bottom Pressure ◽

Special Value ◽

Deep Ocean Circulation

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Analysis of large-scale ocean bottom pressure variability in the North Pacific

Journal of Geophysical Research Atmospheres ◽

10.1029/2008jc004930 ◽

2008 ◽

Vol 113 (C11) ◽

Cited By ~ 30

Author(s):

Don P. Chambers ◽

Josh K. Willis

Keyword(s):

North Pacific ◽

Large Scale ◽

Ocean Bottom ◽

Bottom Pressure ◽

Ocean Bottom Pressure ◽

The North ◽

The North Pacific

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Monitoring Atlantic overturning circulation variability with GRACE-type ocean bottom pressure observations – a sensitivity study

Ocean Science Discussions ◽

10.5194/osd-12-1765-2015 ◽

2015 ◽

Vol 12 (4) ◽

pp. 1765-1791 ◽

Cited By ~ 1

Author(s):

K. Bentel ◽

F. W. Landerer ◽

C. Boening

Keyword(s):

Large Scale ◽

Global Climate ◽

Sensitivity Study ◽

Ocean Basin ◽

Meridional Overturning Circulation ◽

Western Slope ◽

Ocean Bottom ◽

Bottom Pressure ◽

Overturning Circulation ◽

Ocean Bottom Pressure

Abstract. The Atlantic Meridional Overturning Circulation (AMOC) is a key mechanism for large-scale northward heat transport and thus plays an important role for global climate. Relatively warm water is transported northward in the upper layers of the North Atlantic Ocean, and after cooling at subpolar latitudes, sinks down and is transported back south in the deeper limb of the AMOC. The utility of in-situ ocean bottom pressure (OBP) observations to infer AMOC changes at single latitudes has been characterized in recent literature using output from ocean models. We extend the analysis and examine the utility of space-based observations of time-variable gravity and the inversion for ocean bottom pressure to monitor AMOC changes and variability between 20 and 60° N. Consistent with previous results, we find a strong correlation between the AMOC signal and OBP variations, mainly along the western slope of the Atlantic basin. We then use synthetic OBP data – smoothed and filtered to resemble the resolution of the GRACE gravity mission – and reconstruct geostrophic AMOC transport. Due to the coarse resolution of GRACE-like OBP fields, we find that leakage of signal across the step slopes of the ocean basin is a significant challenge at certain latitudes. However, overall, the inter-annual AMOC anomaly time series can be recovered from 20 years of monthly GRACE-like OBP fields with errors less than 1 Sverdrup.

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Analysis of Ocean Bottom Pressure Anomalies and Seismic Activities in the MedRidge Zone

Remote Sensing ◽

10.3390/rs13071242 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1242

Author(s):

Hakan S. Kutoglu ◽

Kazimierz Becek

Keyword(s):

Time Series ◽

Mass Change ◽

Ocean Bottom ◽

Bottom Pressure ◽

Vertical Movements ◽

Ocean Bottom Pressure ◽

Continuous Mass ◽

Mediterranean Ridge Accretionary Complex ◽

Gravity Recovery ◽

Periodic Components

The Mediterranean Ridge accretionary complex (MAC) is a product of the convergence of Africa–Europe–Aegean plates. As a result, the region exhibits a continuous mass change (horizontal/vertical movements) that generates earthquakes. Over the last 50 years, approximately 430 earthquakes with M ≥ 5, including 36 M ≥ 6 earthquakes, have been recorded in the region. This study aims to link the ocean bottom deformations manifested through ocean bottom pressure variations with the earthquakes’ time series. To this end, we investigated the time series of the ocean bottom pressure (OBP) anomalies derived from the Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow-On (GRACE-FO) satellite missions. The OBP time series comprises a decreasing trend in addition to 1.02, 1.52, 4.27, and 10.66-year periodic components, which can be explained by atmosphere, oceans, and hydrosphere (AOH) processes, the Earth’s pole movement, solar activity, and core–mantle coupling. It can be inferred from the results that the OBP anomalies time series/mass change is linked to a rising trend and periods in the earthquakes’ energy time series. Based on this preliminary work, ocean-bottom pressure variation appears to be a promising lead for further research.

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