First Institute of Oceanography, Ministry of Natural Resources, Qingdao 266061, China
Key Laboratory of Marine Environmental Survey Technology and Application, Ministry of Natural Resource, Guangzhou 510310, China
Shandong University of Science and Technology, Qingdao 266590, China
The Open Fund of Key Laboratory of Marine Environmental Survey Technology and Application Ministry of Natural Resource under contract No. MESTA-2020-B005; the Shandong Provincial Natural Science Foundation under contract No. ZR2020QD087; the National Key R&D Program of China under contract Nos 2017YFC0306003 and 2016YFB0501703; the National Natural Science Foundation of China under contract Nos 42104035and 41706115.
Arctic absolute sea level variations are analyzed based on multi-mission satellite altimetry data and tide gauge observations for the period 1993–2018. The range of linear absolute sea level trends are found −2.00 mm/a to 6.88 mm/a excluding the central Arctic, positive trend rates were predominantly located in shallow water and coastal areas, and negative rates were located in high-latitude areas and Baffin Bay. Satellite-derived results show that the average secular absolute sea level trend is (2.53±0.42) mm/a in the Arctic region. Large differences were presented between satellite-derived and tide gauge results, which are mainly due to low satellite data coverage, uncertainties in tidal height processing and vertical land movement (VLM). The VLM rates at 11 global navigation satellite system stations around the Arctic Ocean were analyzed, among which 6 stations were tide gauge co-located, the results indicated that the absolute sea level trends after VLM corrected were of the same magnitude as satellite altimetry results. Accurately calculating VLM is the primary uncertainty in interpreting tide gauge measurements such that differences between tide gauge and satellite altimetry data are attributable generally to VLM.
Figure 1. Fraction of satellite-derived SLA data coverage in the Arctic Ocean of spring: January–March (a), summer: April–June (b), autumn: July–September (c), winter: October–December (d), over the 1993–2018 period.
Figure 2. Geographic locations of tide gauge stations (red circles) and Global Navigation Satellite System stations (blue triangles).
Figure 3. Time series of satellite-derived SLA for the period from January 1993 to December 2018 (a), and the spectral structure of SLA (b). The identified peaks corresponding to the principal components are labelled A–H.
Figure 4. Spatial trend pattern (left) and uncertainties of trend (right) from satellite altimetry over the 1993–2018 period.
Figure 5. Daily vertical land movement time series at GNSS stations.
Figure 6. Relationship between tide gauge observation and satellite-derived result. a. Function of correlation coefficient and distance. Black line present correcoef between tide gauge and the nearest satellite data, red line are the VLM corrected in two stations. b. Tidal height series in IZVESTIA TSIK tide gauge station and satellite-derived result.