Baffin Bay sea ice inflow and outflow: 1978–1979 to 2016–2017
oleh: H. Bi, H. Bi, H. Bi, Z. Zhang, Z. Zhang, Z. Zhang, Y. Wang, Y. Wang, Y. Wang, X. Xu, X. Xu, X. Xu, Y. Liang, Y. Liang, Y. Liang, J. Huang, Y. Liu, M. Fu
| Format: | Article |
|---|---|
| Diterbitkan: | Copernicus Publications 2019-03-01 |
Deskripsi
<p>Baffin Bay serves as a huge reservoir of sea ice which would provide the solid freshwater sources to the seas downstream. By employing satellite-derived sea ice motion and concentration fields, we obtain a nearly 40-year-long record (1978–1979 to 2016–2017) of the sea ice area flux through key fluxgates of Baffin Bay. Based on the estimates, the Baffin Bay sea ice area budget in terms of inflow and outflow are quantified and possible causes for its interannual variations and trends are analyzed. On average, the annual (September–August) inflows through the northern gate and Lancaster Sound are on the order of <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M1" display="inline" overflow="scroll" dspmath="mathml"><mrow><mn mathvariant="normal">205.8</mn><mo>(</mo><mo>±</mo><mn mathvariant="normal">74.7</mn><mo>)</mo><mo>×</mo><msup><mn mathvariant="normal">10</mn><mn mathvariant="normal">3</mn></msup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="94pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="d70f40737eb8af314ae6297545c11d8a"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="tc-13-1025-2019-ie00001.svg" width="94pt" height="15pt" src="tc-13-1025-2019-ie00001.png"/></svg:svg></span></span> km<span class="inline-formula"><sup>2</sup></span> and <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M3" display="inline" overflow="scroll" dspmath="mathml"><mrow><mn mathvariant="normal">55.2</mn><mo>(</mo><mo>±</mo><mn mathvariant="normal">17.8</mn><mo>)</mo><mo>×</mo><msup><mn mathvariant="normal">10</mn><mn mathvariant="normal">3</mn></msup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="88pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="87e1710333a5b7ad5554ea1139c3958d"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="tc-13-1025-2019-ie00002.svg" width="88pt" height="15pt" src="tc-13-1025-2019-ie00002.png"/></svg:svg></span></span> km<span class="inline-formula"><sup>2</sup></span>. In particular, a comparison with published results seems to suggest that about 75 %–85 % of the inflow through the northern gates is newly formed ice produced in the recurring North Water Polynya (NOW), in addition to the inflow via Nares Strait and Jones Sound. Meanwhile, the mean outflow via the southern gate approaches <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M5" display="inline" overflow="scroll" dspmath="mathml"><mrow><mn mathvariant="normal">394.3</mn><mo>(</mo><mo>±</mo><mn mathvariant="normal">110.2</mn><mo>)</mo><mo>×</mo><msup><mn mathvariant="normal">10</mn><mn mathvariant="normal">3</mn></msup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="100pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="52f9186cb9b001e003c77c687b820a99"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="tc-13-1025-2019-ie00003.svg" width="100pt" height="15pt" src="tc-13-1025-2019-ie00003.png"/></svg:svg></span></span> km<span class="inline-formula"><sup>2</sup></span>. The distinct interannual variability for ice area flux through the northern gate and southern gate is partly explained by wind forcing associated with cross-gate sea level pressure difference, with correlations of 0.62 and 0.68, respectively. Also, significant increasing trends are found for the annual sea ice area flux through the three gates, amounting to <span class="inline-formula">38.9×10<sup>3</sup></span>, <span class="inline-formula">82.2×10<sup>3</sup></span>, and <span class="inline-formula">7.5×10<sup>3</sup></span> km<span class="inline-formula"><sup>2</sup></span> decade<span class="inline-formula"><sup>−1</sup></span> for the northern gate, southern gate, and Lancaster Sound. These trends are chiefly related to the increasing ice motion, which is associated with thinner ice owing to the warmer climate (i.e., higher surface air temperature and shortened freezing period) and increased air and water drag coefficients over the past decades.</p>