Carbon pools and fluxes in the China Seas and adjacent oceans

The China Seas include the South China Sea, East China Sea, Yellow Sea, and Bohai Sea. Located off the Northwestern Pacific margin, covering 4700000 km~2 from tropical to northern temperate zones, and including a variety of continental margins/basins and depths, the China Seas provide typical cases for carbon budget studies. The South China Sea being a deep basin and part of the Western Pacific Warm Pool is characterized by oceanic features; the East China Sea with a wide continental shelf, enormous terrestrial discharges and open margins to the West Pacific, is featured by strong cross-shelf materials transport; the Yellow Sea is featured by the confluence of cold and warm waters; and the Bohai Sea is a shallow semiclosed gulf with strong impacts of human activities. Three large rivers, the Yangtze River, Yellow River, and Pearl River, flow into the East China Sea, the Bohai Sea, and the South China Sea, respectively. The Kuroshio Current at the outer margin of the Chinese continental shelf is one of the two major western boundary currents of the world oceans and its strength and position directly affect the regional climate of China. These characteristics make the China Seas a typical case of marginal seas to study carbon storage and fluxes. This paper systematically analyzes the literature data on the carbon pools and fluxes of the Bohai Sea,Yellow Sea, East China Sea, and South China Sea, including different interfaces(land-sea, sea-air, sediment-water, and marginal sea-open ocean) and different ecosystems(mangroves, wetland, seagrass beds, macroalgae mariculture, coral reefs, euphotic zones, and water column). Among the four seas, the Bohai Sea and South China Sea are acting as CO_2 sources, releasing about0.22 and 13.86–33.60 Tg C yr~(-1) into the atmosphere, respectively, whereas the Yellow Sea and East China Sea are acting as carbon sinks, absorbing about 1.15 and 6.92–23.30 Tg C yr~(-1) of atmospheric CO_2, respectively. Overall, if only the CO_2 exchange at the sea-air interface is considered, the Chinese marginal seas appear to be a source of atmospheric CO_2, with a net release of 6.01–9.33 Tg C yr~(-1), mainly from the inputs of rivers and adjacent oceans. The riverine dissolved inorganic carbon (DIC) input into the Bohai Sea and Yellow Sea, East China Sea, and South China Sea are 5.04, 14.60, and 40.14 Tg C yr~(-1),respectively. The DIC input from adjacent oceans is as high as 144.81 Tg C yr~(-1), significantly exceeding the carbon released from the seas to the atmosphere. In terms of output, the depositional fluxes of organic carbon in the Bohai Sea, Yellow Sea, East China Sea, and South China Sea are 2.00, 3.60, 7.40, and 5.92 Tg C yr~(-1), respectively. The fluxes of organic carbon from the East China Sea and South China Sea to the adjacent oceans are 15.25–36.70 and 43.93 Tg C yr~(-1), respectively. The annual carbon storage of mangroves, wetlands, and seagrass in Chinese coastal waters is 0.36–1.75 Tg C yr~(-1), with a dissolved organic carbon(DOC) output from seagrass beds of up to 0.59 Tg C yr~(-1). Removable organic carbon flux by Chinese macroalgae mariculture account for 0.68 Tg C yr~(-1) and the associated POC depositional and DOC releasing fluxes are 0.14 and 0.82 Tg C yr~(-1), respectively. Thus, in total, the annual output of organic carbon, which is mainly DOC, in the China Seas is 81.72–104.56 Tg C yr~(-1). The DOC efflux from the East China Sea to the adjacent oceans is 15.00–35.00 Tg C yr~(-1). The DOC efflux from the South China Sea is 31.39 Tg C yr~(-1). Although the marginal China Seas seem to be a source of atmospheric CO_2 based on the CO_2 flux at the sea-air interface, the combined effects of the riverine input in the area, oceanic input, depositional export,and microbial carbon pump(DOC conversion and output) indicate that the China Seas represent an important carbon storage area.     

黄河龙头水库来水量的年代际变化及年度预测方法

根据1736-2004年近270 a来的代用资料和实测资料,对唐乃亥水文站逐年来水量划分为9个丰水年段,8个枯水年段。在同时段的太阳黑子周期长度（SCL）资料中,找到9个SCL的极长点,8个SCL的极短点,发现SCL的极长（短）点都出现在丰（枯）水年段之中或超前1～2 a。这为黄河源区丰、枯水段的预测找到了一个比较好的指标。最后,从"宇地磁耦合假说"出发,解释其关系密切的物理原因。     

陆面上总体输送系数研究进展

从陆面上总体输送系数的研究历程、计算方法和时空变化特征以及与地面各要素之间的依赖关系等几个方面,对该领域的研究工作进行了回顾和总结。在此基础上,探讨了该领域研究中存在的几点科学问题：①需要解决非均匀下垫面地表参数的计算和观测以及发展适用于非均匀下垫面的相似性理论等难题;②对我国湿润地区地表总体输送系数的研究需要加强;③能否对非均匀复杂下垫面陆气相互作用过程进行全面的认识,地表参数由“点”到“面”的推广是关键也是难题。最后对利用卫星遥感结合地面观测资料估算非均匀下垫面地表特征参数和能量通量的可行方法进行了讨论与展望。     

The Major Two-stage Shortening Deformation of the Northern Tibet and Tian Shan Area Since the Latest Oligocene

It seems to be progressively recognized that the stress of the India-Asia convergent front can be transferred rapidly through the southern and central Tibetan lithosphere to the northern Tibet, hence leading to the crustal thickening deformation there during or immediately after the onset of the India-Asia collision(ca.55 Ma).This study focuses on the late Cenozoic deformation and tectonic uplift of the northern Tibet and Tian Shan area.Detailed compilations of a variety of proxy data from sediments and bedrocks suggest that the northern Tibet and Tian Shan area underwent one stage of approximately synchronous widespread contractile deformation since 25–20 Ma, which seemed to decrease at circa 18 Ma as revealed by low-temperature thermochronological data.The latest Oligocene-early Miocene was also significant basin-forming episodes when many intermontane subbasins began to receive syntectonic sedimentation in the northeastern Tibet.Subsequently, the other phase of compressional deformation began to encroach more widely into the northern Tibet and Tian Shan area in episodic steps or continuously from 16–12 Ma to present.     

1901—2018年三江源地区大气冻融指数变化特征

三江源地区是我国重要生态安全屏障,冻土是其高寒生态系统的重要组成部分,冻土的变化深刻影响高寒生态系统固碳及水源涵养。基于英国东英吉利大学(University of East Anglia,UEA)气候研究中心(Climatic Research Unit,CRU)月平均气温再分析资料,利用线性倾向法和滑动平均法并结合GIS空间分析和制图,计算并分析了三江源地区1901—2018年冻融指数变化趋势及其空间分布特征。结果表明:三江源地区冻结指数在1901—2018年整体以-1.1℃·d·a^-1的斜率呈波动减少趋势,经历了三个波动变化阶段:1901—1943年的下降(-3.4℃·d·a^-1)、1943—1966年的升高(8.8℃·d·a^-1)、1966—2018年的再次下降(-4.3℃·d·a^-1)。融化指数与冻结指数的变化相反,整体以0.34℃·d·a^-1的斜率呈波动上升趋势,呈现升高(1901—1943年,3.3℃·d·a^-1)、下降(1943—1981年...     

CSD和CDD结合下的最优遥感特征指数集构建及其在湿地信息提取中的应用

依托中分辨率成像光谱仪完整的数据序列和丰富的光谱信息,遥感特征指数在湿地生态系统发展变化的状态、趋向和规律研究方面发挥着不可替代的优势.传统类间距离判别的遥感特征指数选取中常存在过分依赖数据统计特征、入选指数与目标地类间生态学意义不明确、分类模型普适性差等局限性.基于此,本研究以河北省白洋淀湿地自然保护区为例,提出类可...     

我国全新世泥炭α纤维素稳定碳同位素记录的对比与分析

泥炭是古气候研究的宝贵材料,α纤维素稳定碳同位素（δ¹³C_cell）是泥炭古气候研究的常用代用指标。我国已有数个地点报道了全新世泥炭全样或单种植物δ¹³C_cell记录,对这些记录的古气候解译存在明显冲突。结合相应的孢粉和植物残体证据,对这些记录进行综合对比,结果发现：高山草地植被带和内陆干旱区荒漠草原植被带当中的泥炭地,全新世期间的原地植物种属构成相对稳定且未发生显著变化,因此其δ¹³C_cell记录具有较为明显的长期变化趋势,其古气候解译也更为可靠;森林植被带和林草交互带当中的泥炭地,全新世期间的原地植物种属构成发生过显著变化（如木本植物入侵）,这可能是造成其全新世δ¹³C_cell记录长期趋势不明显或其古气候指示意义复杂难解的主要原因。这些结果显示了泥炭地的原地植物种属构成,对相应δ¹³C_cell记录的古气候解译的重要影响。同时也表明,无论是泥炭δ¹³C_cell研究地点的选择,还是泥炭δ¹³C_cell记录的古气候解译,都需重视其来源植物种属构成和变化。对于全新世泥炭δ¹³C_cell古气候研究,建议开展针对性的现代过程研究,尤其是优势泥炭植物种属的δ¹³C_cell在时间序列上的现代过程研究,以提供可靠的古气候解译基础。

     

柴达木盆地西部地区断裂类型及油气勘探意义

为研究柴西地区油气成藏及其与青藏高原隆升的关系,我们借助生长断层定性和定量分析,总结出该区断裂在演化上总体可归纳为两个主要形成时期和4种表现形式：早期形成时期(E1＋2?N),中生代以来开始活动,多数终止于下油砂山组末(约14.9 Ma); 晚期形成时期(N?Q),上油砂山组开始活动,狮子沟组(约8.2 Ma)以来活动尤为剧烈,持续至今。在形式上主要表现为限于下或上构造层的生长断层; 贯穿下、上构造层的生长断层和后期断层4类。柴西地区的这种断裂构造特征,与青藏高原的分阶段隆升相对应,控制着该区的油气运移、成藏、保存及改造,对我们在柴西地区的油气勘探工作具有重大意义。     

东北地区春季首场透雨的变化特征及与青藏高原地面加热场强度的关系

利用1958—2012年4—5月东北地区(39°~55°N、118°~135°E)101个站点逐日降水资料、青藏高原地区(25°~40°N、73.75°~103.75°E)JRA-55的地面感热和潜热通量月平均再分析资料以及NCEP/NCAR-I大气环流场的月平均再分析资料,分析了春播期首场透雨出现日期的时空变化特征及其与透雨量和播种期降水量间的关系,以及对青藏高原地面加热场强度异常的响应及其可能机制。结果表明:透雨日期自1958年以来在东北地区的西北和东南大部分区域呈现略微偏晚的趋势;中部有略微偏早的趋势。春播期首场透雨出现时间偏早(晚)的地方,首场透雨量小(大),春播期总降水量多(少)。同时,4月青藏高原地面加热场强度增强(减弱),有利于(不利于)来自北方的冷空气和南方的暖湿气流在东北上空交汇,且上升气流增强(减弱),水汽输送充沛(减少),导致该地区春季首场透雨出现的时间偏早(晚)。     

Size distributions and source function of sea spray aerosol over the South China Sea

The number concentrations in the radius range of 0.06 – 5 μm of aerosol particles and meteorological parameters were measured on board during a cruise in the South China Sea from August 25 to October 12, 2012. Effective fluxes in the reference height of 10 m were estimated by steady state dry deposition method based on the observed data, and the influences of different air masses on flux were discussed in this paper. The number size distribution was characterized by a bimodal mode, with the average total number concentration of(1.50 ± 0.76)×10~3 cm~(-3). The two mode radii were 0.099 μm and 0.886 μm, both of which were within the scope of accumulation mode. A typical daily average size distribution was compared with that measured in the Bay of Bengal. In the whole radius range, the number concentrations were in agreement with each other; the modes were more distinct in this study than that abtained in the Bay of Bengal. The size distribution of the fluxes was fitted with the sum of log-normal and power-law distribution. The impact of different air masses was mainly on flux magnitude, rather than the shape of spectral distribution. A semiempirical source function that is applicable in the radius range of 0.06 μmr_(80)0.3 μm with the wind speed varying from 1.00 m s~(-1) to 10.00 m s~(-1) was derived.