西风爆发、次表层暖水东移与厄尔尼诺现象

利用最近20 a的大气海洋资料,分析了厄尔尼诺事件与赤道太平洋西风异常以及赤道太平洋次表层海温之间的关系.结果表明,赤道西太平洋(5°S～5°N,120°～160°E)和赤道中东太平洋(5°S～5°N,160°E～160°W)西风异常都存在着与厄尔尼诺周期一致的年际变化,但前者还包含有显著的2～3个月季节内振荡.赤道西太平洋次表层冷暖水东移也呈现年和年际时间尺度的振荡周期.在厄尔尼诺发生前,赤道西太平洋次表层海水出现持续性增暖,赤道西太平洋西风异常频率加快,强度增强.随后赤道中太平洋(160°E～160°W)出现持续性(3个月以上)强西风异常(即西风爆发),并进一步向东扩展,同时次表层暖水沿着赤道波导东移到赤道东太平洋混合层,导致赤道东太平洋海表大面积异常增暖,形成一次厄尔尼诺现象.最后,模式模拟了1980～1984年赤道太平洋海温的变化,进一步证实了赤道纬向西风异常对暖水东移起着重要的作用.     

The evolution of oceanic and atmospheric anomalies in the northeast Pacific during the El Niño and La Niña events of 1995–2001

From late 1995 through early 2001, three major interannual climate events occurred in the tropical Pacific; the 1995–97 La Niña (LN), 1997–98 El Niño (EN), and 1998–2001 LN. We analyze atmospheric and upper oceanic anomalies in the northeast Pacific (NEP) during these events, and compare them to anomalies both elsewhere in the north and tropical Pacific, and to typical EN and LN anomaly patterns. The atmospheric and oceanic anomalies varied strongly on intraseasonal and interannual scales. During the 1995–97 LN and 1997–98 EN, the Northeast Pacific was dominated by negative SLP and cyclonic wind anomalies, and by upper ocean temperature and sea surface height (SSH) anomalies. The latter were positive along the North American west coast and in the NEP thermal anomaly pool (between Hawaii, Vancouver Island, and Baja California), and negative in the central north Pacific. This atmospheric/oceanic anomaly pattern is typical of EN. An eastward shift in the atmospheric teleconnection from east Asia created EN-like anomalies in the NEP during the 1995–97 LN, well before the 1997–98 EN had begun. The persistence of negative sea-level pressure (SLP) and cyclonic wind anomalies in the NEP during the 1997–98 EN intensified pre-existing upper oceanic anomalies. Atmospheric anomalies were shifted eastward during late 1996–early 1998, leading to a similar onshore shift of oceanic anomalies. This produced exceptionally strong positive upper ocean temperature and SSH anomalies along the west coast during the 1997–98 EN, and explains the unusual coastal occurrences of several species of large pelagic warm-water fishes. The growth and eastward shift of these pre-existing anomalies does not appear to have been linked to tropical Pacific EN anomalies until late 1997, when a clear atmospheric teleconnection between the two regions developed. Prior to this, remote atmospheric impacts on the NEP were primarily from east Asia. As the 1998–2001 LN developed, NEP anomalies began reversing toward the typical LN pattern. This led to predominantly negative SLP and cyclonic wind anomalies in the NEP, and upper ocean temperature and SSH anomalies that were mainly negative along the west coast and positive in the central north Pacific. The persistence of these anomalies into mid-2001, and a number of concurrent biological changes in the NEP, suggest that a decadal climate shift may have occurred in late 1998.During 1995–2001, NEP oceanic anomalies tracked the overlying atmospheric anomalies, as indicated by the maintenance of a characteristic spatial relationship between these anomalies. In particular, wind stress curl and SSH anomalies in the NEP maintained an inverse relationship that strengthened and shifted eastward toward the west coast during late 1996–early 1998. This consistent relationship indicates that anomalous Ekman transport driven by regional atmospheric forcing was an important contributor to temperature and SSH anomalies in the NEP and CCS during the 1997–98 EN. Other studies have shown that coastal propagations originating from the tropical Pacific also may have contributed to coastal NEP anomalies during this EN. Our results indicate that at least some of this coastal anomaly signal may have been generated by regional atmospheric forcing within the NEP.     

黄河口及其附近海域沉积物中可提取的铅和镍

讨论了黄河口及其附近海域沉积物中１ｍｏｌ盐酸可提取铅与镍的含量范围为铅７．９２～２８．８６ｍｇ／ｋｇ，镍４．５１～１４．７１ｍｇ／ｋｇ，与典型性的五步形态提取地前四部分之和具有可比性。同时Ｉｍｏｌ盐酸提取的铅、镍与可提取锰、铁及沉积物的外比表面积具有很好的正相关。通过进一步的多元回归分析可以发现黄河口及其附近海域沉积物可提取铅主要结合在氧化锰及粘土矿的外表面上，而和铁的关系不明显，可提取镍与铁，锰     

埃尔－尼诺年西北太平洋的台风活动

文中统计分析了１９４９～１９９１年西北太平洋近赤道地区（０°～１０°Ｎ，１２５°～１８０°Ｅ）和热带地区（１０°～２５°Ｎ，１２５°～１８０°Ｅ）的台风日数。发现埃尔－尼诺年上述两地区的台风日数明显偏多。因此，冬、春各季该地区的台风日数、可作为该年是否可能发生埃尔－尼诺的一个预报指标。     

鲤鱼在不同保藏温度下的质量变化

作者对鲤鱼在冰藏(0-2℃)和常温(10℃、15℃、28℃)的保藏条件下,以TVB-N、K值,细菌总数和感官鉴定为鲜度指标,分析了质量变化。根据综合评定:达一级鱼鲜度的期限冰藏约为10天,常温10℃为3天,15℃为1天;达二级鱼鲜度的期限冰藏为18天常温分别为4天,2天和半天左右。可见,冰藏的保存期比常温保藏延长二周以上。作者认为冰藏是鲤鱼保鲜简便有效的方法。同时也证实了在不同保藏温度下,K值因初期变化显著而可作为高标准的鲜度指标。试验中发现TVB-N在保藏后期与细菌总数和感官鉴定不相符,TVB-N值偏低,其中冰藏鲤鱼尤为明显,此现象在鳙、鲢、鲤冻藏试验中也存在,因此,提出以TVB-N作为腐败指标是否适用于冰藏、冻藏的淡水鱼尚需商榷。     

Spatial patterns of ichthyoplankton assemblages in the Río de la Plata Estuary (Argentina–Uruguay)

Two oceanographic surveys were conducted across the salinity gradient of the Río de la Plata Estuary during austral late spring and summer. Ichthyoplankton was dominated by families Sciaenidae, Clupeidae, Engraulidae, Cynoglossidae and Carangidae. The distribution of larval fish assemblages was strongly associated to the salinity structure. Oceanographic conditions were characterized by a large salt wedge (180 km long and a vertical salinity gradient up to 10 units per meter). During both sampling periods each ichthyoplankton assemblage was related to the same region of the salt wedge: the fresh water environment, the bottom salinity front, the mixohaline zone and the outer portion (surface salinity front) of the estuary. Larval assemblages were not related to the thermal structure. Reproductive activity of fishes inside the Río de la Plata Estuary is relatively common (60% of the teleosts sampled use this estuary as a nursery ground). Moreover, the high incidence of pelagic eggs spawners (75% of the species present in the ichthyoplankton) in the Río de la Plata contrasts to the vast majority of estuaries, where this reproductive strategy is poorly represented. Estuarine dynamics plays a dominant role in allowing this reproductive style in this estuary. Spring–summer wind pattern should generate a retentive environment which could minimize advective losses of eggs and larvae to the adjacent ocean.     

地球赤道上空地月距离的4.425a周期与厄尔尼诺、地球自转、海面变化及地裂缝的关系

文中论述了在地球赤道上空,地月距离存在4.425a 的变化周期,是由于月近地点在8.85a的周期性运移中,每到黄径0°和180°(赤道线上)在地球自转的背景下使地月距效果相同所致。而每年的地近日点(1月3日或4日)正置圣诞节过后几天,因此,日、月、地相对运动每隔4.425a 在圣诞节前后三者距离总会达到最近。本文计算了1910～1991年圣诞节前后赤道上空地月距离的变化,发现日、月、地最近时与厄尔尼诺、地球自转、海平面变化,地裂缝等自然现象的发生存在着统计上可以认可的相关性。     

东海G断面平均温、盐度变化与厄尔尼诺关系的初步分析

本文试图利用位于东海黑潮区G断面温、盐度的多年观测资料,对该断面平均温、盐度变化与厄尔尼诺的关系进行了分析,以期有助于研究黑潮对我国东海及邻近海域环流和沿海气候的影响。 Ⅰ.资料来源及统计方法 由于采用的划分标准和指数不同,因而对     

Upper-ocean thermal structure and heat content off the US West Coast during the 1997-1998 El Niño event based on AXBT and satellite altimetry data

During the 1997/1998 El Niño event, extensive oceanic temperature profiles were taken off the coast of California in January and February 1998 using Airborne Expendable Bathythermographs (AXBTs). These AXBT measurements are compared with altimetry-based upper-ocean temperature estimates using TOPEX and ERS satellite altimetry data. The altimetry-based temperature estimates are well correlated with the AXBT data, in particular when combining the two satellite data sets together to form a blended altimeter temperature estimate. Both the AXBT and altimetry data show that the nearshore coastal El Niño signal differed from that further offshore. The AXBT data show that near shore, the warm anomalies extended to much greater depths and had greater amplitude. A time series of the satellite-derived layer-averaged temperatures, averaged separately over the nearshore and offshore halves of the AXBT analysis domain, also shows a larger El Niño signal in the nearshore half. The role of local atmospheric forcing of the coastal oceanic temperature anomalies is analyzed using NCEP reanalysis and coastal upwelling data sets. The forcing terms include Ekman pumping, radiation, surface heat fluxes, precipitation, and alongshore wind stresses that drive coastal upwelling (expressed as a coastal downwelling index, CDI). The temperature forcing from all of the terms except the CDI anomalies are small. The CDI anomalies can explain most of the slowly varying temperature changes that occur near the coast during a two-year period spanning the El Niño event, as well as some of the larger amplitude, rapid (monthly) warming episodes that appear to be part of the El Niño signal. Several distinct rapid warming episodes, however, are not correlated with the CDI anomalies, and therefore we conclude that the nearshore El Niño signal originates from a combination of both a remote oceanic pathway and local atmospheric forcing.