西太平洋暖池冰期旋回中的类ENSO式演化及其驱动机制

作为全球接受太阳辐射最多、表层海水温度最高的区域,西太平洋暖池区通过厄尔尼诺-南方涛动(El Niño-Southern Oscillation,ENSO)和季风等过程影响着全球气候的变化。越来越多的沉积记录证明,在地质历史时期西太平洋暖池也存在类似于现代ENSO过程的“类ENSO式”变化。而目前类ENSO式变化与冰期—间冰期旋回之间的响应关系和驱动机制及其与东亚季风的关联仍存在争议。本文利用位于暖池核心区的B10岩心浮游有孔虫氧同位素、Mg/Ca(质量分数比)和黏土矿物参数重建了暖池区氧同位素8期以来的古气候记录,并结合已有的热带海表温度记录、中国石笋氧同位素和南大洋地区海表温度记录,研究了西太平洋暖池冰期旋回中类ENSO状态的演化规律及其与东亚季风的关系,并探讨了暖池区类ENSO演化的驱动机制。结果发现:冰期时,西太平洋暖池区温跃层变浅,赤道东、西太平洋温差减小,同时,东亚夏季风减弱,暖池区降水量相对减少,与现代El Niño时期气候态类似;间冰期时,西太平洋暖池区温跃层加深,赤道东、西太平洋温差增大,东亚冬夏季风增强,暖池区降水量相对增加,与现代La Niña时期气候态类似。频谱分析结果表明,西太平洋暖池区海表温度的变化具有偏心率周期(96 ka)。冰消期时,低纬度太阳辐射量的增加,增大了纬向上的SST梯度,并使得次表层海水储存了更多的热量,积累的热量会通过调节次表层环流向暖池区的热传输,最终调控赤道太平洋地区Walker环流强度和ENSO活动的长期变化。而冰期时,南大洋地区降温所引起的东南信风和大洋环流异常可能对类ENSO式起到调控的作用。     

基于磷脂脂肪酸的热带西太平洋沉积物生源要素矿化过程探析

甄别生源要素参与的海洋沉积物矿化过程对探析生源要素的生物地球化学循环有重要的作用,矿化作用包括有氧呼吸、硝酸盐还原、铁锰异化还原及硫酸盐还原等多个过程,但如何区分这些过程一直是海洋沉积物矿化研究的难点。本研究采用气相色谱-质谱(GC-MS)联用对热带西太平洋沉积物中的磷脂脂肪酸(phospholipid fatty acid, PLFA)的组成进行了解析,并分析不同矿化过程中的主要PLFA种类及其影响因素,探究PLFA对沉积物矿化的指示作用。结果表明,PLFA总量在有氧呼吸过程中最高,而在硝酸盐还原过程中最低;且14:0、i14:0、i15:0和i19:0是有氧呼吸过程中微生物PLFA的主要组成,当其含量明显降低时可以指示沉积物矿化从有氧呼吸转变为硝酸盐还原;而10:0、17:0、20:0和22:0含量之和显著增加时则指示了硫酸盐还原过程的发生。在热带西太平洋沉积物中,总有机碳(TOC)和总有机氮(TON)含量以及间隙水NO₃-N含量是PLFA含量的重要影响因素,PLFA总量随着TOC和TON含量的减少而减少,并且TOC和TON的降解能够促进PLFA降解的发生,对PLFA组成有更直接的影响。     

The role of the Indian Ocean in determining the tropical pacific SST response to radiative forcing in an idealized model

The complexity of the tropical climate system demands the development of a hierarchy of models to ensure our understanding of its response to anthropogenic forcing. The response of the tropical Pacific Ocean to radiative forcing has been studied previously with a box model. The model has provided insights into the tropical Pacific climate change that are otherwise not easily attainable. But that model only encompasses the tropical Pacific region. Recent studies have also shown that the Indian Ocean (IO) may be important in the response of the Pacific Walker circulation to radiative forcing, raising the need to expand the model to take into account the role of IO. This study presents the results concerning the tropical Pacific response to radiative forcing from an expanded-box model that includes the tropical IO, which influences the tropical Pacific through an inter-basin SST gradient.The three-box model predicts an enhanced zonal SST gradient in tropical Pacific in response to the increased radiative forcing, similar to the previous two-box model. It is further noted that in the three-box model, a warmer IO relative to the Pacific enhances Pacific easterlies and subsequently strengthens the equatorial ocean circulation. Because of this ocean dynamical cooling, the warming response in the Pacific is effectively reduced in the three-box model that includes the role of IO compared with that in the two-box model. The role of the IO warming trend in enhancing the Pacific trade winds is confirmed using an atmospheric general circulation model experiment. These results may help to fully explain the relatively small observed warming trend in the tropical Pacific compared to that in the tropical IO evident in 20th century SST reconstructions.     

Overcoming barriers to climate change information management in small island developing states: lessons from pacific SIDS

We live in a rapidly advancing digital information age where the ability to discover, access and utilize high-quality information in a reliable and timely manner is often assumed to be the norm. However, this is not always the experience of researchers, practitioners and decision makers responding to the challenges of a rapidly changing climate, despite the billions now being made available for investment in climate change adaptation initiatives throughout the world and particularly in developing countries. In recognition of the importance of information in adaptation planning, Article 7.7 of the Paris Agreement sets out clear guidance for parties to develop, share, manage and deliver climate change knowledge, information and data as a means to strengthening cooperation and action on adaptation. This article provides some key lessons and insights on climate change information and knowledge management (IKM) in small island developing States (SIDS) from the perspective of Pacific SIDS. A situation analysis of current climate change IKM practices in Fiji, Tonga and Vanuatu was conducted and key barriers to effective climate change IKM identified. The outcome of this article is a range of pragmatic policy considerations for overcoming common barriers to climate change IKM in the Pacific, which may be of value to SIDS more widely.

Key policy insights

• The partnership approach of co-investigating climate change IKM barriers in collaboration with Pacific SIDS generated considerable trust, a shared purpose and therefore rich IKM lessons and insights.

• Turning climate change IKM aspirations into practice is significantly more complicated than expected, and requires a long-term commitment from both national governments and development partners.

• Pacific SIDS need to establish national guiding climate change IKM Frameworks that leverage rather than duplicate growing national investments in whole-of-government IKM.

• Reframing climate change IKM in the Pacific towards demand and user needs will be critical to ensuring widespread ownership and participation in IKM solutions that lead to greater adaptation and resilience outcomes.

• It is also critical that IKM activities in SIDS support the development of national capacity to scope, develop, deploy and maintain decision support systems.

• Federated IKM systems are ideal for encouraging greater IKM collaboration.

     

东北那丹哈达岭中—新生代构造-热演化史:来自(U-Th)/He和裂变径迹热年代学的证据

中国东北的那丹哈达岭地区位于中亚造山带最东部,它的中新生代热演化史是认识陆内造山活动的关键,但该地区相关研究比较薄弱,其中—新生代的热演化史缺乏有效的约束.因此本文应用磷灰石裂变径迹、锆石和磷灰石(U-Th)/He等多种低温热年代学方法,对东北那丹哈达岭地区的侵入岩开展构造热演化历史研究.热年代学数据和热史模拟结果表明,该地区存在早白垩世晚期—晚白垩世(110～80Ma)、古新世—始新世(60～40 Ma)两期快速冷却事件,其冷却速率分别为3.42～4.81℃/Ma和1.43～1.83℃/Ma.结合区域构造和应力分析,我们认为两期冷却事件均受构造活动控制.第一期快速冷却事件是古太平洋板块北西向俯冲引发的构造叠加到鄂霍特莫茨克地块并与东亚大陆边缘碰撞引起;而第二期快速冷却事件是古太平洋俯冲的板片后撤使东亚陆缘处于伸展环境,造成东北大面积的剥露作用引起.这次研究增强了对东亚陆缘中新生代构造-热演化历史的认识,对于理解大陆内部造山带的构造变形过程与机理具有重要意义.     

Generation of high resolution sea surface temperature using multi-satellite data for operational oceanography

In the present article, we introduce a high resolution sea surface temperature(SST) product generated daily by Korea Institute of Ocean Science and Technology(KIOST). The SST product is comprised of four sets of data including eight-hour and daily average SST data of 1 km resolution, and is based on the four infrared(IR) satellite SST data acquired by advanced very high resolution radiometer(AVHRR), Moderate Resolution Imaging Spectroradiometer(MODIS), Multifunctional Transport Satellites-2(MTSAT-2) Imager and Meteorological Imager(MI), two microwave radiometer SSTs acquired by Advanced Microwave Scanning Radiometer 2(AMSR2), and Wind SAT with in-situ temperature data. These input satellite and in-situ SST data are merged by using the optimal interpolation(OI) algorithm. The root-mean-square-errors(RMSEs) of satellite and in-situ data are used as a weighting value in the OI algorithm. As a pilot product, four SST data sets were generated daily from January to December 2013. In the comparison between the SSTs measured by moored buoys and the daily mean KIOST SSTs, the estimated RMSE was 0.71°C and the bias value was –0.08°C. The largest RMSE and bias were 0.86 and –0.26°C respectively, observed at a buoy site in the boundary region of warm and cold waters with increased physical variability in the Sea of Japan/East Sea. Other site near the coasts shows a lower RMSE value of 0.60°C than those at the open waters. To investigate the spatial distributions of SST, the Group for High Resolution Sea Surface Temperature(GHRSST) product was used in the comparison of temperature gradients, and it was shown that the KIOST SST product represents well the water mass structures around the Korean Peninsula. The KIOST SST product generated from both satellite and buoy data is expected to make substantial contribution to the Korea Operational Oceanographic System(KOOS) as an input parameter for data assimilation.     

Testing coral paleothermometers (B/Ca,Mg/Ca,Sr/Ca,U/Ca andδ18O) under impacts of large riverine runoff

Sea surface temperature (SST) proxies including B/Ca, Mg/Ca, Sr/Ca, U/Ca andδ18O were analyzed in the skeleton of aPorites coral collected from the Zhujiang River (Pearl River) Estuary (ZRE). These geo...     

长牡蛎nacrein 基因的克隆、结构及进化分析

首次在长牡蛎(Crassostrea gigas)中克隆得到一种新的贝壳基质蛋白nacrein-like protein F3的全长c DNA序列。nacrein-like protein F3基因c DNA全长1499bp,其中编码区长度为1242bp,编码一条含413个氨基酸残基的多肽链。氨基酸序列比对和结构域分析均表明其为合浦珠母贝(Pinctada fucata)nacrein的同源蛋白,含有1个保守的α-碳酸酐酶结构域,但由于重复结构域的插入,α-碳酸酐酶结构域被间隔成2个亚结构域。系统进化分析显示nacrein-like protein F3与贻贝(Mytilus californianus)nacrein-like protein进化关系最近。此外,在软体动物中,双壳纲nacrein-like proteins进化速度相对较快,推测与寒武纪时期剧烈的环境变化有关,如影响贝壳形成的海水化学变化。     

Influence of Tropical Western Pacific Warm Pool Thermal State on the Interdecadal Change of the Onset of the South China Sea Summer Monsoon in the Late-1990s

An interdecadal shift in the onset date of the South China Sea summer monsoon(SCSSM) is identified during the late 1990 s by using the European Centre for Medium-Range Weather Forecasts Interim Reanalysis dataset. The mean onset date was brought forward by two pentads during 1999–2013 compared to that during 1979–1998. The large-scale atmospheric and oceanic change associated with this shift exhibits a significant interdecadal variation signal around 1998/1999, indicating that the shift during the late 1990 s is robust. Different from the well-known mid-1990 s shift, this shift carried more important systematical significance. Diagnostic analysis suggests that the earlier outbreak of the SCSSM was due to the interdecadal warming of the warm pool, which brought stronger convection anomalies and led to a weak western Pacific subtropical high(WPSH) during boreal spring(March–May). The earlier retreat of the WPSH was a direct cause of this shift.     

Different Warming Patterns of Tropical Pacific Sea Surface Temperature Projected by FGOALS-g2 and FGOALS-s2 under RCP8.5

The different patterns of SST changes under the +8.5 W m-2 Representative Concentration Pathway(RCP8.5) projected by the latest two versions of the Flexible Global Ocean-Atmosphere-Land System model(FGOALS-g2 and FGOALS-s2; grid-point version 2 and spectral version 2, respectively), and the potential mechanisms for their formation are studied in this paper. The results show that, although both FGOALS-g2 and FGOALS-s2 project global warming patterns, FGOALS-g2(FGOALS-s2) projects a La Nia-like(an El Nio-like) mean warming pattern with weakest(strongest) warming over the central(eastern) equatorial Pacific for 2081–2100 relative to 1986–2005 under RCP8.5. A mixed layer heat budget analysis shows that the projected tropical Pacific Ocean warming in both models is primarily caused by atmospheric forcing. The main differences in the heating terms contributing to the SST changes between the two models are seen in the downward longwave radiation and ocean forcing. The minimum SST warming over the equatorial Pacific in FGOALS-g2 is attributed to the local minimum heating of downward longwave radiation and maximum cooling of ocean forcing. In contrast, the maximum SST warming over the equatorial Pacific in FGOALS-s2 is due to the maximum warming of downward longwave radiation, and the contribution of ocean forcing is minor. The minimum SST warming over the equatorial Pacific in FGOALS-g2 emerges around the 2050 s, before when the SST over the equatorial Pacific is warmer than that over the extra-equatorial Pacific. In FGOALS-s2, the SST difference shows a continuous increasing trend for 2006– 2100. Further examination of the oceanic and atmospheric circulation changes is needed to reveal the process responsible for the longwave radiation and ocean forcing difference between the two models.