楚科奇海悬浮体含量分布及其颗粒组分特征

对中国第四次北极科学考察在楚科奇海获取的悬浮体样品进行悬浮体及其颗粒组分特征的分析,旨在了解楚科奇海悬浮体分布、成因特征以及其沉积学意义。研究发现,楚科奇海中部悬浮体浓度最低,而在靠近白令海峡的南部海域和中北部海域,中下层海水中发现两个悬浮体浓度高值区。楚科奇海阿拉斯加沿岸和巴罗峡谷底层海水中,悬浮体浓度相对较高。扫描电镜分析结果显示,楚科奇海南部和中北部中下层海水中的悬浮体,主要以硅藻为主,但这两个海域的硅藻优势种明显不同。阿拉斯加沿岸和巴罗峡谷中的悬浮体,以生物碎屑为主。结合楚科奇海温度、盐度资料,楚科奇海南部和中北部高浓度悬浮体分别受经白令海峡夏季入侵的太平洋海水和楚科奇海冬季残留水的控制,而阿拉斯加沿岸和巴罗峡谷中下层的悬浮体,则受阿拉斯加沿岸流的控制。     

1999年夏季中国首次北极考察区水团特征

依据 1 999年 7月至 9月中国首次北极考察队在白令海、楚科奇海和南加拿大海盆的现场调查资料 ,本文分析了三个海区的水团特征 :( 1 )白令海水团主要由季节变化显著的白令海上层水团和中层水团以及深层水团组成 ;( 2 )楚科奇海水文特征受融结冰过程影响较大 ,1 999年7月和 8月差异较大 ,其水团主要为浅海变性水团 ,包括两个次级水团 ,楚科奇海夏季水和来自北太平洋以及北冰洋变性的外海入侵水 ;( 3)南加拿大海盆的水团主要由受融结冰过程影响的表层水团、源于太平洋水的次表层水、源自北大西洋的中层水团和深层水团组成     

Predicting air temperature simultaneously for multiple locations in an urban environment: A bottom up approach

Cities are characterized by high heterogeneity that results in varied microclimate effects. The current study introduces a new bottom–up approach linking the urban Canyon Air Temperature (CAT) model with spatially distributed inputs extracted from a GIS data-base and remote sensing products to predict intra-urban temperature variability simultaneously for multiple locations in an urban environment. To provide proof of concept, the model was applied for the city of Bat-Yam, Israel. Simulation shows a maximum nighttime urban heat island (UHI) intensity of 2–2.25 °C, relative to a rural reference point, during both summer and winter, with significant spatial variability related to the height-to-width ratio of urban street canyons and to the surface land cover. The CAT simulation also highlighted the important influence of the local wind regime on the development and persistence of the nocturnal UHI. We conclude that linking CAT to a GIS data-base supports simulations at the city scale that reflect the local intra-urban variability. The model can be used to investigate both macro and micro scale spatio-temporal characteristics of the UHI in various urban development scenarios, which may be applied to generate appropriate geographically-explicit mitigation and adaptation measures.     

Assessing potential environmental influences on killer whale (Orcinus orca) distribution patterns in the Bremer Canyon,south-west Australia

ABSTRACT

Submarine canyons play an important role in the regional distribution, abundance and dispersal of marine biota and are increasingly being recognised as geomorphic features of high conservation significance along Australia’s continental margin. Certain canyons have been described as foraging ‘hotspots’ attributable to the high abundance of apex cetacean species aggregating in these areas. Anecdotal evidence of large seasonal aggregations of killer whales in the Bremer Canyon, south-west Australia, has attracted significant research attention in the last decade. To identify important environmental drivers influencing aggregation patterns, a predictive spatial habitat model using the Maxent model was developed based on presence-only whale sighting data. In addition, remotely sensed sea surface temperature and chlorophyll-a concentrations were assessed to investigate the spatio-temporal variation in sea surface conditions. Habitat preference was predicted in areas between canyon heads, with the most influential predictor variables being depth and distance from the continental shelf break. Analysis of remote-sensing data highlighted low localised variability in surface waters and illustrated the seasonal trends of the Leeuwin Current. This study demonstrates the influence of bathymetry and submarine geomorphology on enhanced cetacean abundance and highlights the need for recognition of this potential foraging area in marine reserve planning.     

青藏高原考察新发现--帕隆藏布大峡谷

通过多年的考察和室内科学论证,发现认定在雅鲁藏布大峡谷顶端汇流的一级支流———帕隆藏布峡谷也是一条堪称世界级的大峡谷（照片１）。就深度而言,帕隆藏布至少可以排位于尼泊尔王国境内的喀利根德格大峡谷（最深为４４０３ｍ）之后名列世界第三而深于秘鲁的科尔卡大...     

1950~2011年渤海地区海表风场的季节特征与多尺度变化分析

基于1950~2011年的NCEP/NCAR再分析资料,对渤海10 m风场的风速与风向变化进行多尺度分析。利用小波分析、交叉谱分析等方法对渤海海域的海表风速、风向的变化趋势以及周期进行研究。分析发现：渤海地区海表风的风向与风速除了存在显著的季节性变化特征外,在年际、年代际的变化尺度上也有明显的周期性。风向存在1 a、8.7 a、15.8 a的显著周期,风速存在1 a、6.3 a、15 a的显著周期。风向与风速在时间尺度分别为20 a、5.71 a、2.67 a时存在显著共振周期;共振周期受东亚季风、西太平副热带高压的年际、年代际变化的影响呈现出多尺度变化周期。     

Meridional zonation of the Barents Sea ecosystem inferred from satellite remote sensing and in situ bio-optical observations

The Barents Sea is a productive, shallow, high-latitude marine ecosystem with complex hydrographic conditions. Zonal hydrographic bands defined by a coastal current. North Atlantic Water, the Polar Front, and the seasonally variable marginal ice edge zone create a meridional zonation of the ecosystem during the spring-summer transition. The features reveal themselves in satellite imagery and by high-resolution (vertical and horizontal) physical-optical-biological sampling.
Surprisingly, the long-term (7-year) mean of Coastal Zone Color Scanner (CZCS) imagery reveals the Barents Sea as an anomalous "blue-water" regime at high latitudes that are otherwise dominated by satellite-observed surface blooms. A combination of satellite imagery and in situ bio-optical analyses indicate that this pattern is caused by strong stratification in summer with surface nutrient depletion. The onset of stratification of the entire region is linked to the extent of the winter ice edge: cold years with extensive sea ice apparently stratify early due to ice melt; warm years stratify later, perhaps due to weaker thermal stratification of the Atlantic waters (e.g. Skjoldal et al. 1987). The apparent "low chlorophyll" indicated by the CZCS 7-year mean is partly due to sampling error whereby the mean is dominated by images taken later in the summer. In fact, massive blooms of subsurface phytoplankton embedded in the pycnocline persist throughout the summer and maintain substantial rates of primary production. Further, these subsurface blooms that are not observed by satellite are responsible for dramatic gradients in the beam (c₁) and spectral diffuse (k) attenuation coefficients. The Barents Sea exemplifies the need to couple satellite observations with spatially and temporally resolved biogeographic ecosystem models in order to estimate the integrated water column primary production, mass flux or spectral light attenuation coefficients.     

The role of Pacific water in the dramatic retreat of arctic sea ice during summer 2007

A model study is conducted to examine the role of Pacific water in the dramatic retreat of arctic sea ice during summer 2007.The model generally agrees with the observations in showing considerable seasonal and interannual variability of the Pacific water inflow at Bering Strait in response to changes in atmospheric circulation. During summer 2007 anomalously strong southerly winds over the Pacific sector of the Arctic Ocean strengthen the ocean circulation and bring more Pacific water into the Arctic than the recent(2000-2006) average.The simulated summer(3 months) 2007 mean Pacific water inflow at Bering Strait is 1.2 Sv,which is the highest in the past three decades of the simulation and is 20%higher than the recent average.Particularly ,the Pacific water inflow in September 2007 is about 0.5 Sv or 50%above the 2000-2006 average.The strengthened warm Pacific water inflow carries an additional 1.0×10~(20) Joules of heat into the Arctic,enough to melt an additional 0.5 m of ice over the whole Chukchi Sea.In the model the extra summer oceanic heat brought in by the Pacific water mainly stays in the Chukchi and Beaufort region,contributing to the warming of surface waters in that region.The heat is in constant contact with the ice cover in the region in July through September.Thus the Pacific water plays a role in ice melting in the Chukchi and Beaufort region all summer long in 2007,likely contributing to up to 0.5 m per month additional ice melting in some area of that region .     

1979-2012年北极海冰范围年际和年代际变化分析

利用美国冰雪中心发布的海冰密集度数据,对1979—2012年北极海冰范围进行年际和年代际变化分析。结果表明:(1)海冰在秋季融化速度最快,其次为夏季、冬季、春季。2000年后春季下降速率变缓,而其他季节融化速度加快;(2)由于多年冰的融化,太平洋扇区在夏秋季节融化速度要高于其他海区。而大西洋扇区在冬季和春季海冰的融化速度要快于夏秋季节,主要是因为大西洋海温升高;(3)东半球在夏秋季节海冰融化的范围要大于西半球,因此东北航道比西北航道提前开通应用。而整个北极区域近几年春季融化速度变缓,则主要是西半球的作用;(4)从空间分布年代际变化来看,1989—1998年最接近气候态,1979—1988年密集度偏大区域主要在巴伦支海和东西伯利亚海,2009—2012年海冰密集度较常年显著偏小,东半球密集度减小幅度比西半球更大,尤其是冬春季在巴伦支海,夏秋季在楚科奇海。春季时由于风的作用,白令海附近海冰密集度异常偏大;(5)北极区域海冰范围在冬春季比夏秋季突变明显,基本在2003年前后,海冰范围变化周期为6年。     

北极Barrow地区几种冻原植物的花粉形态

本文研究了北极巴罗 (Barrow)地区 1 2种冻原植物的花粉形态 ,它们的形状有球形、近球形、扁球形茧形和四合体型 ,其萌发孔有三孔沟、三沟、二合沟以及散孔等类型。花粉具辐射对称和两侧对称两种类型。这些花粉的植物体是北极冻原地区常见的植物 ,分属于 1 2个科 ,除 3种为小灌木外 ,大多数为多年生或一年生草本植物。这些冻原植物花粉形态的研究为恢复北极地区古植被和古气候的研究 ,提供了有价值的对比资料和依据。     

陕西汛雨开始日期异常的气候特征及其影响系统

利用陕西省1961-2018年逐日降水资料、NCEP/NCAR再分析资料及NOAA海温资料,基于合成分析、相关分析等方法,研究了陕西汛雨开始早晚的气候特征及其影响系统.结果表明:陕西入汛日具有显著的年际和年代际变化特征,20世纪60年代主要以偏晚为主,70、80年代以偏早为主,90年代偏晚,进入21世纪以后以偏早为主,...     

Interannual variability of dense shelf water salinities in the north-western Barents Sea

The maximum dense shelf water salinity formed during winter in the Svalbard Bank area of the north-western Barents Sea is reconstructed for the period 1952–2000 by analysing the transformation of summer remnants. The variability of 34.7 - 35.4, waters being at the freezing point, is mainly generated by interannual variations in the near surface salinity. On interannual time scales the latter is strongly linked to the sea ice import. In contrast, no correlation of the salinity of the Atlantic Water (AW) throughflow to the Arctic Ocean with the ice import is found. Salinities of both the dense shelf water site in the north-west Barents Sea and the north-eastward AW throughflow show a long term decrease, which can partly be explained by a less saline inflow of AW from the Norwegian Sea. The unusually low dense water salinities in the north-west Barents Sea during the 1990s appear to have a different origin, consistent with a response to oceanic heat advection and decreasing sea ice extent.     

Surface temperatures of the Barents Sea

Temperature conditions in the Barents Sea are determined by the quality and quantity of the inflowing Atlantic water from the west and by processes taking part in the Barents Sea itself, in particular as a consequence of winter cooling and ice formation. The field of inflow to the Barents Sea during the period 1977-1987 has been studied. The surface winter temperatures within the Barents Sea vary in parallel with variations in the deeper layers of the inflowing water masses, whereas the surface temperatures in summer have a different variation pattern which is most likely dependent on the summer heating process.     

雅鲁藏布大峡谷地区水环境评价及保护研究

雅鲁藏布大峡谷是世界第一大峡谷,位于我国西藏南部喜马拉雅山脉东端,穿过大峡谷的河流是世界上海拔最高的大河雅鲁藏布江。大峡谷地区由于地形复杂,山高谷深,交通不便而且人口相对稀少,因此受人类活动影响较少,水环境的原始自然状态保持完好。本文根据笔者参加1998年徒步穿越雅鲁藏布大峡谷科学探险考察中取得的第一手资料,对大峡谷地区原始自然状态下的水文和水环境特征做了初步研究,并对今后大峡谷水环境的保护和监测提出了具体的建议。     

Satellite-derived primary productivity and its spatial and temporal variability in the China seas

The spatial and temporal variability of primary productivity in the China seas from 2003 to 2005 was estimated using a size-fractionated primary productivity model. Primary productivity estimated from satellite-derived data showed spatial and temporal variability. Annual averaged primary productivity levels were 564.39, 363.08, 536.47, 413.88, 195.77, and 100.09 gCm-2a-1 in the Bohai Sea, northern Yellow Sea (YS), southern YS, northern East China Sea (ECS), southern ECS, and South China Sea (SCS), respectively. Peaks of primary productivity appeared in spring (April–June) and fall (October and November) in the northern YS, southern YS, and southern ECS, while a single peak (June) appeared in the Bohai Sea and northern ECS. The SCS had two peaks in primary productivity, but these peaks occurred in winter (January) and summer (August), with the winter peak far higher than the summer peak. Monthly averaged primary productivity values from 2003 to 2005 in the Bohai Sea and southern YS were higher than those in the other four seas during most months, while those in the southern ECS and SCS were the lowest. Primary productivity in spring (March–June in the southern ECS and April–July in the other five areas) contributed approximately 41% on average to the annual primary productivity in all the study seas except the SCS. The largest interannual variability also occurred in spring (average standard deviation = 6.68), according to the satellite-derived estimates. The contribution during fall (October–January in the southern ECS and August–November in the other five areas) was approximately 33% on average; the primary productivity during this period also showed interannual variability. However, in the SCS, the winter (December–March) contribution was the highest (about 42%), while the spring (April–July) contribution was the lowest (28%). The SCS did share a feature with the other five areas: the larger the contribution, the larger the interannual variability. Spatial and temporal variability of satellite-derived ocean primary productivity may be influenced by physicochemical environmental conditions, such as the chlorophyll-a concentration, sea surface temperature, photosynthetically available radiation, the seasonally reversed monsoon, river discharge, upwelling, and the Kuroshio and coastal currents.     

西北太平洋及其在东亚气候上的问题

作者前在「海水温度与水旱问题」(注一)一文中,曾以东亚海水表面温度为根据,研讨我国长江中下游流域或其南部的旱潦关系。发现太平洋西北隅的水温,对日本和长江流域中下游的旱潦问题有相当关系。本文拟讨论上述海区中的海洋     

Morphotectonics and incision of the Kaoping submarine canyon, SW Taiwan orogenic wedge

The Kaoping submarine canyon developed on the frontal orogenic wedge off SW Taiwan and is the largest one among others. The canyon begins at the mouth of the Kaoping River, crosses the narrow shelf and broad slope region, and finally merges into the northern Manila Trench for a distance of about 260 km. Using reflection seismic sections and bathymetric mapping this paper reveals the geomorphic characteristics of the Kaoping Canyon strongly related to structural and sedimentary processes. The combined morphometry statistics analysis, seismic interpretations of structures and examinations of detailed bathymetric charts indicate that regional canyon morphology is strongly linked to intrusions of mud diapirs in the upper reach of the canyon and thrust faulting in the middle and lower reaches which produce two prominent morphological breaks of the course of the Kaoping Canyon with two sharp bends. Although excavation of floor and enlargement of the Kaoping Canyon are mainly attributed to downslope erosion of seabed, incision of this canyon is also strongly complicated by mud diapiric intrusions (upper reach), westward thrust faults (middle reach), and regional base level tilting (lower reach). The resultant cross-sectional morphology along the Kaoping Canyon changes considerably, ranging from U-shaped, broad V-shaped, to irregular troughs. The Kaoping Canyon may be served as a variant of canyon model of active margins with a distinct morphology of two sharp bends along the canyon course associated with structure deformation.     

针对北极地区典型月份期间的大气数值模拟分析

本文利用极地中尺度数值模式Polar MM5对2005年7月17日～19日, 2007年12月20日～24日北极地区大气环流进行了中尺度数值模拟, 分析比较了北极夏季典型代表月7月间和冬季典型代表月12月间大气特征。数值分析表明,在500hPa高度上,12月和7月极区的大气环流都主要由2个波动控制;夏季的冰岛低压在冬季表现为一个高压系统,并且伸展到格陵兰岛上空。我们选择了2个北极地区探空站与相应温度场和风场的数值模拟结果进行了对比,表明数值模式能够很好地再现观测到得大气分布特征,表现为小的模式偏差和较高的相关系数。夏季7月份期间, Barrow 站2m处空气温度,感热通量和潜热通量具有明显的日变化特征和极地逆温层结垂直结构特征;冬季12月份期间,Barrow 站2m处空气温度,感热通量和潜热通量呈现出反位相变化的特征,虽然各通量峰值远小于夏季时的情形,但是北极所考虑站点下垫面在冬季12月和夏季7月份都是大气的热源和水汽源。     

Modeling seasonal variations of ocean and sea ice circulation in the Beaufort and Chukchi Seas:A model-data fusion study

A 3.8-km Coupled Ice-Ocean Model(CIOM) was implemented to successfully reproduce many observed phenomena in the Beaufort and Chukchi seas,including the Bering-inflow-originated coastal current that splits into three branches: Alaska Coastal Water(ACW),Central Channel,and Herald Valley branches.Other modeled phenomena include the Beaufort Slope Current(BSC),the Beaufort Gyre, the East Siberian Current(ESC),mesoscale eddies,seasonal landfast ice,sea ice ridging,shear,and deformation.Many of these downscaling processes can only be captured by using a high-resolution CIOM,nested in a global climate model.The seasonal cycles for sea ice concentration,thickness,velocity,and other variables are well reproduced with solid validation by satellite measurements.The seasonal cycles for upper ocean dynamics and thermodynamics are also well reproduced,which include the formation of the cold saline layer due to the injection of salt during sea ice formation,the BSC,and the subsurface upwelling in winter that brings up warm,even more saline Atlantic Water along the shelfbreak and shelf along the Beaufort coast.     

ENSO循环过程对南极海冰的影响

应用 1 951- 2 0 0 2年NINO特征指数 (NINO1 +2 ,NINO3 ,NINO4 ,NINO3 .4)和 1 973-1 998年南极海冰北界范围以及 1 950- 2 0 0 1年SODA海洋温度资料。首先分析探讨了在ElNi no期间 ,堆积于赤道东太平洋的异常暖水在南半球的传播途径 ,进而研究了ENSO以及东南太平洋异常海温场与南极海冰之间的关系。结果表明 ,在ElNino期间 ,堆积于赤道东太平洋的异常暖水 ,是沿秘鲁和智利沿岸向极传播。其传播过程持续大约 1年的时间 ,但未发现沿南赤道流的西传现象。ENSO循环过程与南极海冰变化存在一定联系 ,特别是Amundsen Belling shausen海和南极半岛海冰的变化与ENSO暖事件 (ElNino)较为密切。当ElNino事件发生后 ,时滞 2年左右的时间 ,Amundsen Bellingshausen海和南极半岛的海冰将出现明显的减少现象 ,特别是南极半岛的海冰减少最为明显。ElNino事件对南极海冰的影响过程是 ,堆积于赤道东太平洋的大量异常暖水 ,沿南美 (秘鲁和智利 )沿岸近海向极地传播 ,异常暖水的这种向极传播过程将引起近极的海温场出现异常升高 ,最终导致Amundsen Bellingshausen海和南极半岛地区的海冰减少。自 2 0世纪 80年代以来 ,Amundsen Bellingshausen海和南极半岛的海冰出现明显减少的趋势 ,与这一时期的ElNino事件的频繁发生