Measuring Ocean Bottom Pressure at the North Pole

2014 ◽  
Vol 48 (5) ◽  
pp. 52-68 ◽  
Author(s):  
Cecilia Peralta-Ferriz ◽  
James H. Morison ◽  
Scott E. Stalin ◽  
Christian Meinig
Keyword(s):  
Arctic Ocean ◽  
Ground Truth ◽  
Satellite System ◽  
North Pole ◽  
Ocean Bottom ◽  
Bottom Pressure ◽  
Ground Truth Data ◽  
Ocean Bottom Pressure ◽  
The North ◽  
Aircraft Landing

AbstractHigh-precision deep Arctic Bottom Pressure Recorders (ABPRs) were developed to measure ocean bottom pressure variations in the perennial ice-covered Arctic Ocean. The ABPRs use the tsunami detection DART acoustic modem technology and have been programmed to store and transmit the data acoustically without the need to recover the instrument. ABPRs have been deployed near the North Pole, where the ice cover is a year-round challenge for access with a ship. Instead, the ABPRs have been built as light-weight mechanical systems that we can install using aircraft landing on the ice. ABPRs have provided the first records of uninterrupted pressure data over continuous years ever made in the central Arctic. The ABPR data have allowed us to identify and understand modes of Arctic Ocean bottom pressure variability that were unknown before the ABPR records and have offered new means of investigating and understanding the rapidly changing Arctic system. The ABPR records have also shown outstanding agreement with the satellite-sensed ocean bottom pressure anomalies from GRACE, providing ground truth data for validation of the satellite system. Due to the successful science findings as well as the ABPRs' capability to fulfill the upcoming potential gaps of pressure measurements between GRACE and a GRACE follow-on mission, we highlight the urgent need to develop and maintain an Arctic observing network using ABPRs.

Arctic Ocean bottom pressure variations from 2002 to 2020: merging GRACE with GRACE-FO

2020 ◽  
Author(s):  
Cecilia Peralta-Ferriz ◽  
James Morison ◽  
Jennifer Bonin
Keyword(s):  
Time Series ◽  
Arctic Ocean ◽  
Ocean Circulation ◽  
Ocean Bottom ◽  
Bottom Pressure ◽  
Ocean Bottom Pressure ◽  
The North ◽  
Circulation Patterns ◽  
Arctic Ocean Circulation

<p>Ocean bottom pressure (OBP) from the Gravity Recovery and Climate Experiment (GRACE) revealed Arctic Ocean circulation patterns and variability that were previously unknown (Morison et al., 2007; Morison et al., 2012; Peralta-Ferriz et al., 2014). OBP measurements from the GRACE Follow-On mission (GRACE-FO) are therefore increasingly important for monitoring Arctic Ocean variability, and critical for understanding and predicting the fate of the rapidly changing Arctic environment.</p> <p>In this work we use GRACE data from 2002 to 2017 jointly with a 10-year record of <em>in situ</em> OBP at the North Pole (2005-2015) complemented with <em>in situ</em> OBP in the Canada Basin (2015-2018), and wind reanalysis products, to create a proxy representation of the OBP anomalies that explains the largest possible fraction of the observed OBP variability in the Arctic Ocean and the Nordic Seas. We do this by performing a linear regression analysis, combined with maximum covariance analysis (MCA) – a technique that was tested prior to the decommission of GRACE and the launch of GRACE-FO (Peralta-Ferriz et al., 2016). Here, the first predictor time series is the <em>in situ</em> OBP record at the North Pole and Canada Basin; the second predictor time series is the expansion coefficients time series of the leading mode of MCA between the GRACE OBP coupled with the winds. We use this proxy OBP to merge GRACE with the first 2 years of available GRACE-FO OBP. We compare our merged OBP field with OBP output from the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS). Preliminary results suggest a good agreement between the proxy and predicted OBP fields and both GRACE and GRACE-FO data, especially in the central Arctic, but also in the Nordic Seas. The OBP variations from the merged GRACE and GRACE-FO and from PIOMAS will be also explored.</p> <p><strong>References:</strong></p> <ul> <li>Morison, J. H., J. Wahr, R. Kwok and C. Peralta-Ferriz (2007), Recent trends in Arctic Ocean mass distribution revealed by GRACE, Res. Lett.,34, L07602, doi:10.1029/2006GL029016.</li> <li>Morison, J., R. Kwok, C. Peralta-Ferriz, M. Alkire, I. Rigor, R. Andersen and M. Steele (2012), Changing Arctic Ocean freshwater pathways. Nature, 481, 66-7</li> <li>Peralta-Ferriz, C., J. H. Morison, J. M. Wallace, J. Bonin and J. Zhang (2014), Arctic Ocean circulation patterns revealed by GRACE, of Climate, 27:1445–1468 doi:10.1175/JCLI-D-13-00013.1.</li> <li>Peralta-Ferriz, C., J. H. Morison and J. M. Wallace(2016), Proxy representation of Arctic ocean bottom pressure variability: Bridging gaps in GRACE observations,  Res. Lett., 43, 9183–9191, doi:10.1002/2016GL070137</li> </ul>

scholarly journals Low-frequency ocean bottom pressure variations in the North Pacific in response to time-variable surface winds

2014 ◽  
Vol 119 (8) ◽  
pp. 5190-5202 ◽  
Author(s):  
C. Petrick ◽  
H. Dobslaw ◽  
I. Bergmann-Wolf ◽  
N. Schön ◽  
K. Matthes ◽  
...  
Keyword(s):  
North Pacific ◽  
Low Frequency ◽  
Time Variable ◽  
Ocean Bottom ◽  
Surface Winds ◽  
Bottom Pressure ◽  
Ocean Bottom Pressure ◽  
The North ◽  
Variable Surface ◽  
The North Pacific

scholarly journals Approaching Freshet beneath Landfast Ice in Kugmallit Bay on the Canadian Arctic Shelf: Evidence from Sensor and Ground Truth Data

ARCTIC ◽  
2009 ◽  
Vol 61 (1) ◽  
pp. 76 ◽  
Author(s):  
Tony R. Walker ◽  
Jon Grant ◽  
Peter Jarvis
Keyword(s):  
Arctic Ocean ◽  
Ground Truth ◽  
Open Water ◽  
Early Spring ◽  
The Arctic ◽  
Ground Truth Data ◽  
The North ◽  
Landfast Ice ◽  
North American Arctic ◽  
Mackenzie River

The Mackenzie River is the largest river in the North American Arctic. Its huge freshwater and sediment load impacts the Canadian Beaufort Shelf, transporting large quantities of sediment and associated organic carbon into the Arctic Ocean. The majority of this sediment transport occurs during the freshet peak flow season (May to June). Mackenzie River-Arctic Ocean coupling has been widely studied during open water seasons, but has rarely been investigated in shallow water under landfast ice in Kugmallit Bay with field-based surveys, except for those using remote sensing. We observed and measured sedimentation rates (51 g m-2 d-1) and the concentrations of chlorophyll a (mean 2.2 ?g L-1) and suspended particulate matter (8.5 mg L-1) and determined the sediment characteristics during early spring, before the breakup of landfast ice in Kugmallit Bay. We then compared these results with comparable data collected from the same site the previous summer. Comparison of organic quality in seston and trapped material demonstrated substantial seasonal differences. The subtle changes in biological and oceanographic variables beneath landfast ice that we measured using sensors and field sampling techniques suggest the onset of a spring melt occurring hundreds of kilometres farther south in the Mackenzie Basin.

scholarly journals A basin-coherent mode of sub-monthly variability in Arctic Ocean bottom pressure

2011 ◽  
Vol 38 (14) ◽  
pp. n/a-n/a ◽  
Author(s):  
Cecilia Peralta-Ferriz ◽  
James H. Morison ◽  
John M. Wallace ◽  
Jinlun Zhang
Keyword(s):  
Arctic Ocean ◽  
Ocean Bottom ◽  
Bottom Pressure ◽  
Ocean Bottom Pressure ◽  
Coherent Mode

scholarly journals Validation of the EGSIEM GRACE Gravity Fields Using GNSS Coordinate Timeseries and In-Situ Ocean Bottom Pressure Records

2018 ◽  
Vol 10 (12) ◽  
pp. 1976 ◽  
Author(s):  
Qiang Chen ◽  
Lea Poropat ◽  
Liangjing Zhang ◽  
Henryk Dobslaw ◽  
Matthias Weigelt ◽  
...  
Keyword(s):  
Time Series ◽  
Signal To Noise Ratio ◽  
Satellite System ◽  
Ocean Bottom ◽  
Bottom Pressure ◽  
Ocean Bottom Pressure ◽  
Global Gravity ◽  
Gravity Fields ◽  
Global Navigation Satellite

Over the 15 years of the Gravity Recovery and Climate Experiment (GRACE) mission, various data processing approaches were developed to derive time-series of global gravity fields based on sensor observations acquired from the two spacecrafts. In this paper, we compare GRACE-based mass anomalies provided by various processing groups against Global Navigation Satellite System (GNSS) station coordinate time-series and in-situ observations of ocean bottom pressure. In addition to the conventional GRACE-based global geopotential models from the main processing centers, we focus particularly on combined gravity field solutions generated within the Horizon2020 project European Gravity Service for Improved Emergency Management (EGSIEM). Although two validation techniques are fully independent from each other, it is demonstrated that they confirm each other to a large extent. Through the validation, we show that the EGSIEM combined long-term monthly solutions are comparable to CSR RL05 and ITSG2016, and better than the other three considered GRACE monthly solutions AIUB RL02, GFZ RL05a, and JPL RL05.1. Depending on the GNSS products, up to 25.6% mean Weighted Root-Mean-Square (WRMS) reduction is obtained when comparing GRACE to the ITRF2014 residuals over 236 GNSS stations. In addition, we also observe remarkable agreement at the annual period between GNSS and GRACE with up to 73% median WRMS reduction when comparing GRACE to the 312 EGSIEM-reprocessed GNSS time series. While the correspondence between GRACE and ocean bottom pressure data is overall much smaller due to lower signal to noise ratio over the oceans than over the continents, up to 50% agreement is found between them in some regions. The results fully confirm the conclusions found using GNSS.

Proxy representation of Arctic ocean bottom pressure variability: Bridging gaps in GRACE observations

2016 ◽  
Vol 43 (17) ◽  
pp. 9183-9191 ◽  
Author(s):  
Cecilia Peralta-Ferriz ◽  
James H. Morison ◽  
John M. Wallace
Keyword(s):  
Arctic Ocean ◽  
Ocean Bottom ◽  
Bottom Pressure ◽  
Ocean Bottom Pressure

scholarly journals ENSO-correlated fluctuations in ocean bottom pressure and wind-stress curl in the North Pacific

Ocean Science ◽  
2011 ◽  
Vol 7 (5) ◽  
pp. 685-692 ◽  
Author(s):  
D. P. Chambers
Keyword(s):  
Wind Stress ◽  
North Pacific ◽  
Low Frequency ◽  
Ocean Model ◽  
Ocean Bottom ◽  
Bottom Pressure ◽  
Wind Stress Curl ◽  
Ocean Bottom Pressure ◽  
The North ◽  
The North Pacific

Abstract. We examine the output of an ocean model forced by ECMWF winds to study the theoretical relationship between wind-induced changes in ocean bottom pressure in the North Pacific between 1992 until 2010 and ENSO. Our analysis indicates that while there are significant fluctuations correlated with some El Niño and La Niña events, the correlation is still relatively low. Moreover, the ENSO-correlated variability explains only 50 % of the non-seasonal, low-frequency variance. There are significant residual fluctuations in both wind-stress curl and ocean bottom pressure in the region with periods of 4-years and longer. One such fluctuation began in late 2002 and has been observed by the Gravity Recovery and Climate Experiment (GRACE). Even after accounting for possible ENSO-correlated variations, there is a significant trend in ocean bottom pressure in the region, equivalent to 0.7 ± 0.3 cm yr−1 of sea level from January 2003 until December 2008, which is confirmed with steric-corrected altimetry. Although this low-frequency fluctuation does not appear in the ocean model, we show that ECMWF winds have a significantly reduced trend that is inconsistent with satellite observations over the same time period, and so it appears that the difference is due to a forcing error in the model and not an intrinsic error.

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