Past, Present, and Future Pacific Sea‐Level Change. Issue 4 (2nd April 2021)

• Record Type: Journal Article
• Authors: Hamlington, B. D.; Frederikse, T.; Thompson, P. R.; Willis, J. K.; Nerem, R. S.; Fasullo, J. T.
• Is Part Of: Earth's future. Volume 9:Issue 4(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-04-02
• Subjects: satellite altimetry -- sea‐level -- trends; Environmental sciences -- Periodicals; Environmental sciences; Periodicals; 550
• DOI: 10.1029/2020EF001839
• Languages: English
• ISSNs: 2328-4277

Abstract

Abstract: Satellite altimeters have provided near‐global coverage of the ocean with a continuous record now approaching 3 decades. These observations have led to definitive evidence of an increase in global mean sea‐level, while offering a depiction of the spatial variability in sea‐level change. As a result of the increasing length of the altimeter record, studies have sought to understand and detect the emergence of a forced or anthropogenic response in sea‐level. The central idea behind these studies is that the altimeter record is now long enough that the influence of interannual to decadal variability is reduced and does not obscure underlying regional trends in the way that it did for the early part of the altimeter record. Two locations—the western tropical Pacific and the northeastern Pacific off the west coast of the United States—are noteworthy for their sea‐level variations during the altimeter era, exhibiting large departures from the global average albeit in opposite directions. In this study, we examine satellite altimeter‐measured sea‐level in these two regions. The goals are to understand the evolution of the sea‐level trend, and determine what can be inferred about future sea‐level change from the satellite altimeter record. We find that in the two locations considered here the altimetry record is still too short to rule out natural variability contributions to the trend on the order of 1 mm/yr. Using longer records from tide‐gauge observations and models, an assessment of the potential future changes in both regions is made for both regions. Plain Language Summary: Satellite altimeters have provided near‐global coverage of the ocean with a continuous record now approaching 3 decades in length. With this length of record, the influence of shorter‐term variability is reduced and it is possible a trend associated with anthropogenic forcing may emerge. Two locations—the western tropical Pacific and the northeastern Pacific off the west coast of the United States—are particularly noteworthy for their sea‐level variations during the altimeter era, exhibiting large departures from the global average albeit in opposite directions. Here, we find that the altimeter‐measured trends in these two regions are still impacted by natural variability, while also finding that the anthropogenic‐related sea‐level signal will likely emerge in coming years. Key Points: The western tropical Pacific and the northeastern Pacific off the west coast of the US have seen shifts in sea‐level in the past decade Sea‐level trends in these regions have evolved during the 26‐year satellite‐altimeter record, reflecting natural and forced contributions The altimetry record is still too short to rule out natural variability contributions to the 26‐year trend on the order of 1 mm/yr