## 1. Introduction

[2] The ability of models to represent seasonal and interannual variability of sea surface height (SSH) is an important indicator of model validity because sea level (SL) or SSH reflects changes in practically all dynamic and thermodynamic processes of terrestrial, oceanic, atmospheric, and cryospheric origin. Approximately 70 tide-gauge stations in the Barents and Siberian Seas (Kara, Laptev, East Siberian, and Chukchi Seas) have recorded SL changes from the 1950s through the 2000s (Table 1 and Figure 1 in *Proshutinsky et al.* [2004]). These data are available for model validation at the Permanent Service for Mean Sea Level archive (http://www.pol.ac.uk/psmsl/pub/nucat.dat) and at the Woods Hole Oceanographic Institution web site (http://www.whoi.edu/science/PO/arcticsealevel).

[3] Figure 1 shows the longest SL time series from 9 coastal stations in the Siberian Seas (see Figure 2 and Table 1 for station locations). There is a positive SL trend along the Arctic coastlines. For 1954–1989 the rate of SL rise for these stations was estimated as 0.194 cm/yr [*Proshutinsky et al.*, 2004]. Adding 1990–2006 data increases the estimated rate for these stations to 0.25 cm/yr. The SL time series correlates relatively well with the annual AO index (source: NOAA National Weather Service Climate Prediction Center http://www.cpc.noaa.gov), SLP at the North Pole (source: NCAR/NCEP reanalysis product) and SLP at the coastal stations mentioned above. Consistent with the influences of AO-driven processes, the SL dropped significantly after 1990 and increased after the circulation regime changed from cyclonic to anticyclonic in 1997 (*Proshutinsky and Johnson* [1997], updated).

Station Number and Name | Latitude | Longitude | Period, years | Station Number and Name | Latitude | Longitude | Period, years | ||
---|---|---|---|---|---|---|---|---|---|

1 Bolvanskii Nos | 70.450N | 59.083 E | 1951–92 | 2 Amderma^{a} | 69.750 N | 61.700 E | 1950–06 | ||

3 Russkaia Gavan’ | 76.183 N | 62.583 E | 1953–92 | 4 Harasavei | 71.417 N | 67.583 E | 1954–93 | ||

5 Zhelania | 76.950 N | 68.550 E | 1951–95 | 6 Dikson | 73.500 N | 80.400 E | 1950–96 | ||

7 Uedinenia | 77.500 N | 82.200 E | 1953–94 | 8 Izvestii CIK^{a} | 75.950 N | 82.950 E | 1954–06 | ||

9 Sterlegova | 75.417 N | 88.900 E | 1950–94 | 10 Isachenko | 77.150 N | 89.200 E | 1954–92 | ||

11 Golomianyi^{a} | 79.550 N | 90.617 E | 1954–06 | 12 Pravdy | 76.267 N | 94.767 E | 1950–93 | ||

13 Fedorova | 77.717 N | 104.300 E | 1950–99 | 14 Andreia | 76.750 N | 110.750 E | 1951–98 | ||

15 Preobrazhenia | 74.667 N | 112.933 E | 1951–90 | 16 Dunai^{a} | 73.933 N | 124.500 E | 1951–06 | ||

17 Tiksi^{a} | 71.583 N | 128.917 E | 1949–06 | 18 Muostakh | 71.550 N | 130.033 E | 1951–94 | ||

19 Kotel'nyi^{a} | 76.000 N | 137.867 E | 1951–06 | 20 Sannikova^{a} | 74.667 N | 138.900 E | 1950–06 | ||

21 Kigiliakh | 73.333 N | 139.867 E | 1951–99 | 22 Shalaurova^{a} | 73.183 N | 143.233 E | 1950–06 | ||

23 Ambarchik | 69.617 N | 162.300 E | 1950–99 | 24 Chetyrehstolbovoi | 70.633 N | 162.483 E | 1951–93 | ||

25 Aion | 69.933 N | 167.983 E | 1954–99 | 26 Pevek^{a} | 69.700 N | 170.250 E | 1950–06 | ||

27 Billingsa | 69.883 N | 175.767 E | 1953–94 | 28 Mys Shmidta | 68.900 N | 179.367 W | 1950–93 | ||

29 Vrangelia | 70.983 N | 178.483 W | 1950–99 | 30 Vankarem | 67.833 N | 175.833 W | 1950–99 |

[4] In contrast, from 2000 to 2006 the SL increased in spite of steady low AO index. Because of the large interannual variability, it is difficult to evaluate the significance of this change, but an analysis of model results can provide some insight into these recently observed changes. Of course, this is only possible if the model results agree well with the observational data. The major purpose of this study is to validate AOMIP models against SL observations by determining their major differences and causes for those differences. A second goal of this paper is to recommend model improvements by introducing neglected effects and mechanisms important for SL variability.