DOI: 10.1016/j.epsl.2018.08.059
Scopus记录号: 2-s2.0-85053217753
论文题名: What drives 20th century polar motion?
作者: Adhikari S. ; Caron L. ; Steinberger B. ; Reager J.T. ; Kjeldsen K.K. ; Marzeion B. ; Larour E. ; Ivins E.R.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 502 起始页码: 126
结束页码: 132
语种: 英语
英文关键词: Earth rotation
; glacial isostatic adjustment
; mantle convection
; polar motion
; surface mass transport
Scopus关键词: Digital storage
; Error statistics
; Glacial geology
; Sea level
; Surface reconstruction
; Earth rotation
; Glacial Isostatic Adjustments
; Mantle convection
; Polar motion
; Surface mass transport
; Tectonics
; amplitude
; glacioisostasy
; mantle convection
; mass movement
; mass transport
; polar motion
; secular variation
; twentieth century
; Canada
; Labrador
; Newfoundland and Labrador
英文摘要: Astrometric and geodetic measurements show that the mean position of Earth's spin axis drifted through the solid crust toward Labrador, Canada at an average speed of 10.5±0.9 cm/yr during the 20th century. Understanding the origins of this secular polar motion (SPM) has significance for modeling the global climate, as it provides a link to ice mass balance and sea-level rise. A perplexing issue, however, is that while glacial isostatic adjustment (GIA) models satisfactorily explain the direction of SPM, the associated prediction of the amplitude is insufficient. Our Bayesian GIA analysis, with constraints from relative sea-level and vertical land motion data, reveals that this process only accounts for 33±18% of the observed SPM amplitude. This shortfall motivates a more broadly scoped reassessment of SPM drivers. To address this, we assemble a complete reconstruction of Earth's surface mass transport derived from recent advancements in modeling the global 20th century cryospheric, hydrologic, oceanic, and seismogenic mass exchange. The summed signals, nonetheless, cannot fully reconcile the observed SPM, even when considering the error statistics of each driver. We investigate an additional excitation source: changes in Earth's inertia tensor caused by mantle convection. Sophisticated models have recently been advanced in tectonic plate reconstructions, in conjunction with geoid and seismic tomographic models. Here we use these models to compute new estimates of SPM. While the convection-driven SPM has considerable uncertainty, the average direction of 283 recent models aligns with the residual SPM (within 2.7∘±14.8∘), significantly reducing the gap between observation and prediction. We assert that one key mechanism for driving 20th century SPM is long-term mass movement due to mantle convection. © 2018 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109651
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States; GFZ German Research Centre for Geosciences, Potsdam, Germany; Centre for Earth Evolution and Dynamics, University of Oslo, Oslo, Norway; Department of Geodesy, Technical University of Denmark, Kongens Lyngby, Denmark; Geological Survey of Denmark and Greenland, Copenhagen, Denmark; Institute of Geography, University of Bremen, Bremen, Germany
Recommended Citation:
Adhikari S.,Caron L.,Steinberger B.,et al. What drives 20th century polar motion?[J]. Earth and Planetary Science Letters,2018-01-01,502