Autumn atmospheric preconditioning for interannual variability of wintertime sea-ice in the Okhotsk Sea
Autumn atmospheric preconditioning for interannual variability of wintertime sea-ice in the Okhotsk Sea
复制标题
DOI：
10.1007/s10872-007-0026-5
复制
发表时间：
2007-04
影响因子：
2.3
通讯作者：
Y. Sasaki;Yurika Katagiri;S. Minobe;I. Rigor
中科院分区：
文献类型：
--
作者：
Y. Sasaki;Yurika Katagiri;S. Minobe;I. Rigor
利用奇异值分解方法研究了鄂霍次克海冬季海冰浓度（SICs）与1000 hPa纬向和纬向风速及850 hPa气温异常的年际变化关系。结果表明，晚秋（11月）的大气条件强烈影响海冰的变化，从同一季节（晚秋）到冬末（2月至3月），其中海冰的范围是在其最大值。秋季海冰正距平的大气条件表现为鄂霍次克海上空冷空气温度异常和从西伯利亚吹入鄂霍次克海的风异常。这些大气条件产生异常的海洋-大气热通量和寒冷的海表温度异常的鄂霍次克海。因此，这些结果表明，大气条件影响海冰通过热异常存储在海冰和海洋领域。晚秋的大气条件与白令海和北方欧亚大陆700 hPa高度场的大异常有关，它们分别与北太平洋和北大西洋到欧亚大陆的定常Rossby波传播有关。此外，晚秋大气预处理也起着重要的作用，在鄂霍次克海冰范围的减少趋势，从1980年到20世纪90年代中期观察。基于海冰对晚秋大气的滞后响应，提出了一个简单的季节预报方案，利用4个月的领先大气条件对2 - 3月海冰范围进行预报。该方案解释了鄂霍次克海冰范围变化的45%。
Relations in year-to-year variability between wintertime Sea-Ice Concentrations (SICs) in the Okhotsk Sea and atmospheric anomalies consisting of zonal and meridional 1000-hPa wind speeds and 850-hPa air temperatures are studied using a singular value decomposition analysis. It is revealed that the late autumn (October–November) atmospheric conditions strongly influence sea-ice variability from the same season (late autumn) through late winter (February—March), in which sea-ice extent is at its maximum. The autumn atmospheric conditions for the positive sea-ice anomalies exhibit cold air temperature anomalies over the Okhotsk Sea and wind anomalies blowing into the Okhotsk Sea from Siberia. These atmospheric conditions yield anomalous ocean-to-atmosphere heat fluxes and cold sea surface temperature anomalies in the Okhotsk Sea. Hence, these results suggest that the atmospheric conditions affect the sea-ice through heat anomalies stored in sea-ice and oceanic fields. The late autumn atmosphere conditions are related to large 700-hPa geopotential height anomalies over the Bering Sea and northern Eurasia, which are related to a stationary Rossby wave propagation over the North Pacific and that from the North Atlantic to Eurasia, respectively. In addition, the late autumn atmospheric preconditioning also plays an important role in the decreasing trend in the Okhotsk sea-ice extent observed from 1980 to the mid-1990s. Based on the lagged sea-ice response to the late autumn atmosphere, a simple seasonal prediction scheme is proposed for the February–March sea-ice extent using four-month leading atmospheric conditions. This scheme explains 45% of the variance of the Okhotsk sea-ice extent.