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1.
沉积物硼(B)同位素组成可以反映其地质成因及经历的地质过程,因此在许多领域的研究中都有较为广泛的应用。通过对位于柴达木盆地碱山背斜顶部的SG-1b钻孔沉积物(7.3~1.6 Ma)水溶组分的B同位素研究,发现钻孔沉积物B含量在38.55~172.3μg/g之间,平均含量为87.6μg/g;δ~(11)B值的变化范围在3.61‰~16.26‰之间,平均值为10.65‰,B含量与δ~(11)B值具有一定的正相关关系。进一步分析表明,受到碱山背斜构造隆升以及晚新生代以来气候干旱化的影响,柴西古湖逐渐咸化萎缩,沉积环境以及碳酸盐含量、粘土矿物含量及其矿物组合等也在发生变化,B含量和δ~(11)B值自钻孔底部向上的逐步增加以及后期的急剧增加,与水溶离子含量以及矿物和粒度等的变化一致,这说明柴达木盆地晚中新世以来湖泊沉积物的B含量和δ~(11)B值可以很好地反映研究区气候和湖水的演化过程,共同指示了研究区自7.3 Ma以来气候的持续干旱化和湖水盐度的逐步增加,以及3.3Ma以来干旱化和湖水浓缩过程的加剧。  相似文献   
2.
庞冉  王文 《干旱区地理》2020,43(5):1242-1252
中国西北干旱地区的气候变化及其对植被的影响一直备受关注。以地形特殊的吐鲁番盆 地为研究对象,利用实测气象站点数据、再分析气象格点数据以及 MODIS 卫星遥感植被指数,采用 趋势检验、线性回归、偏相关分析等方法,探究了该地区 2001—2017 年间的植被变化及其与水热组 合特征之间的关系。结果表明:(1)吐鲁番盆地降水量整体没有显著变化,但北部山区降水增长较 多,气温总体呈显著上升趋势,尤其是盆地底部中心区域增温较大。(2)全区域植被指数(NDVI)总 体呈极显著上升趋势,山区及中心区域 NDVI 增长率较大。(3)受水汽来源和日照时长的影响,吐鲁 番盆地周边山区高程 3 000 m 左右 NDVI 值最高,山区植被最好的坡向是西北坡。(4)吐鲁番盆地水 热组合复杂,水分条件是大部分地区植被生长的主要限制因素,降水与 NDVI 有较好的正相关,在 山区和荒漠区热量增加不利于植被生长,但中心区域受地下水和人类活动影响,水分的供给相对 稳定,热量增加利于植被生长。  相似文献   
3.
The temporal and spatial distributions of Antarctic sea ice play important roles in both the generation mechanisms and the signal characteristics of microseisms. This link paves the way for seismological investigations of Antarctic sea ice. Here we present an overview of the current state of seismological research about microseisms on Antarctic sea ice. We first briefly review satellite remote-sensing observations of Antarctic sea ice over the past 50 years. We then systematically expound upon the generation mechanisms and source distribution of microseisms in relation to seismic noise investigations of sea ice, and the characteristics of Antarctic microseisms and relationship with sea ice variations are further analyzed. We also analyze the continuous data recorded at seismic station BEAR in West Antarctica from 2011 to 2018 and compare the microseism observations with the corresponding satellite remote-sensing observations of Antarctic sea ice. Our results show that:(1) the microseisms from the coastal regions of West Antarctica exhibit clear seasonal variations, SFM with maximum intensities every April-May and minimum intensities around every October-November; while DFM intensities peak every February-March, and reach the minimum around every October. Comparatively, the strong seasonal periodicity of Antarctic sea ice in better agreement with the observed DFM; and (2) microseism decay is not synchronous with sea ice expansion since the microseism intensity is also linked to the source location, source intensity (e.g., ocean storms, ocean wave field), and other factors. Finally, we discuss the effect of Southern Annular Mode on Antarctic sea ice and microseisms, as well as the current limitations and potential of employing seismological investigations to elucidate Antarctic sea ice variations and climate change.  相似文献   
4.
文章主要选取国家海洋局成山头海洋环境监测站1996—2016年的潮位、潮差月值资料,利用线性回归法,对威海沿岸海域近21年来的潮汐特征进行分析。结果表明:威海沿岸海域近21年的平均潮位、最高潮位、最低潮位、平均潮差、最大潮差整体上均呈上升的变化趋势,但气候倾向率各不相同,分别是2.57cm/(10a)、5.872cm/(10a)、4.137cm/(10a)、1.017cm/(10a)、2.604cm/(10a)。  相似文献   
5.
The Glycerol Dialkyl Glycerol Tetraethers (GDGTs) occur ubiquitously in a wide range of environments, such as loess, peat, lake, soil, and ocean, which vary compositionally in response to environmental changes, and provide a series of biomarker proxies for paleoenvironmental reconstruction. This paper introduced the structures and biological sources of GDGTs, and reviewed the recent progresses of the application of the GDGTs proxies in the paleoenvironmental reconstruction of loess deposits. The main progresses include: The GDGTs proxies have been widely used in reconstructing the climate changes in loess deposits, and have established the temperature changes of last 800 ka for the Chinese Loess Plateau; Temperature variations in Chinese Loess Plateau displayed significant correlation with the Northern Hemisphere insolation, which may be also regulated by the surface vegetation conditions; and In the Chinese Loess Plateau, the increase in monsoon precipitation during the last deglaciation significantly lagged behind the rise of temperature. However, problems still exist in the current studies. For instance, the GDGTs-based temperature is likely overestimated, probably reflecting the temperature of warm season, and relationships between GDGT indices and climate factors are still unclear. In the future, the development of new proxies and more accurate regional calibrations based on the separation of 6- methyl GDGTs are expected to provide more reliable paleoenvironmental information, and will provide essential evidence for the evolution of hydrothermal pattern and mechanisms behind climate changes in different regions.  相似文献   
6.
Human presence, coastal erosion, and tourism activities are increasing the attention to coastal flooding risk. To perform risk assessments, long time series of observed or hindcast wave parameters and tide levels are then necessary. In some cases, only a few years of observation are available, so that observed extreme data are not always representative and reliable. A hindcast system aimed to reconstruct long time series of total tide levels may be of great help to perform robust extreme events analysis and then to protect human life, activities as well as to counteract coastal erosion by means of risk assessments. This work aims to propose a simplified method to hindcast storm surge levels time series in semi-enclosed basins with low computational costs. The method is an extension of a previous work of some of the authors and consists of a mixed approach in which the estimation of storm surge obtained by using the theory of linear dynamic system is corrected by using a statistical method. Both steps are characterized by low computational costs. Nevertheless, the results may be considered reliable enough also in view of the simplicity of the approach. The proposed method has been applied to the Manfredonia case study, a small village located in the Southern Adriatic Italian coast and often prone to coastal flooding events. The comparison of extreme events estimated on the basis of hindcast levels time series is satisfactorily similar to those estimated on the basis of observed tide series.  相似文献   
7.
Understanding the spatio-temporal characteristics of water storage changes is crucial for Ethiopia, a country that is facing a range of challenges in water management caused by anthropogenic impacts as well as climate variability. In addition to this, the scarcity of in situ measurements of soil moisture and groundwater, combined with intrinsic “scale limitations” of traditional methods used in hydrological characterization are further limiting the ability to assess water resource distribution in the region. The primary objective of this study is therefore to apply remotely sensed and model data over Ethiopia in order to (i) test the performance of models and remotely sensed data in modeling water resources distribution in un-gauged arid regions of Ethiopia, (ii) analyze the inter-annual and seasonal variability as well as changes in total water storage (TWS) over Ethiopia, (iii) understand the relationship between TWS changes, rainfall, and soil moisture anomalies over the study region, and (iv) identify the relationship between the characteristics of aquifers and TWS changes. The data used in this study includes; monthly gravity field data from the Gravity Recovery And Climate Experiment (GRACE) mission, rainfall data from the Tropical Rainfall Measuring Mission (TRMM), and soil moisture from the Global Land Data Assimilation System (GLDAS) model. Our investigation covers a period of 8 years from 2003 to 2011. The results of the study show that the western part and the north-eastern lowlands of Ethiopia experienced decrease in TWS water between 2003–2011, whereas all the other regions gained water during the study period. The impact of rainfall seasonality was also seen in the TWS changes. Applying the statistical method of Principal Component Analysis (PCA) to TWS, soil moisture and rainfall variations indentified the dominant annual water variability in the western, north-western, northern, and central regions, and the dominant seasonal variability in the western, north-western, and the eastern regions. A correlation analysis between TWS and rainfall indicated a minimum time lag of zero to a maximum of six months, whereas no lag is noticeable between soil moisture anomalies and TWS changes. The delay response and correlation coefficient between rainfall and TWS appears to be related to recharge mechanisms, revealing that most regions of Ethiopia receive indirect recharge. Our results also show that the magnitude of TWS changes is higher in the western region and lower in the north-eastern region, and that the elevation influences soil moisture as well as TWS.  相似文献   
8.
《China Geology》2021,4(2):329-352
In the context of global climate change, geosciences provide an important geological solution to achieve the goal of carbon neutrality, China’s geosciences and geological technologies can play an important role in solving the problem of carbon neutrality. This paper discusses the main problems, opportunities, and challenges that can be solved by the participation of geosciences in carbon neutrality, as well as China’s response to them. The main scientific problems involved and the geological work carried out mainly fall into three categories: (1) Carbon emission reduction technology (natural gas hydrate, geothermal, hot dry rock, nuclear energy, hydropower, wind energy, solar energy, hydrogen energy); (2) carbon sequestration technology (carbon capture and storage, underground space utilization); (3) key minerals needed to support carbon neutralization (raw materials for energy transformation, carbon reduction technology). Therefore, geosciences and geological technologies are needed: First, actively participate in the development of green energy such as natural gas, geothermal energy, hydropower, hot dry rock, and key energy minerals, and develop exploration and exploitation technologies such as geothermal energy and natural gas; the second is to do a good job in geological support for new energy site selection, carry out an in-depth study on geotechnical feasibility and mitigation measures, and form the basis of relevant economic decisions to reduce costs and prevent geological disasters; the third is to develop and coordinate relevant departments of geosciences, organize and carry out strategic research on natural resources, carry out theoretical system research on global climate change and other issues under the guidance of earth system science theory, and coordinate frontier scientific information and advanced technological tools of various disciplines. The goal of carbon neutrality provides new opportunities and challenges for geosciences research. In the future, it is necessary to provide theoretical and technical support from various aspects, enhance the ability of climate adaptation, and support the realization of the goal of carbon peaking and carbon neutrality.  相似文献   
9.
10~30 d延伸期可预报性与预报方法研究进展   总被引:1,自引:0,他引:1       下载免费PDF全文
10~30 d延伸期的可预报性既依赖于初始条件,也与缓变的下垫面有关,寻找延伸期时段内可预报性较高的低频特征,识别延伸期的可预报性来源及影响的物理机制是提高延伸期预报水平的关键。近年延伸期可预报性来源、热带大气季节内振荡监测预测和影响等领域的研究取得较大进展,提出和应用了动力统计相结合以及大气低频信号释用等新的延伸期预报方法。对延伸期可预报性来源及其与初值和外强迫异常的关系分析表明,海气相互作用能提高亚洲和西太平洋区域延伸期时段大气环流和要素的可预报性。热带大气季节内振荡、平流层爆发性增温以及各种次季节尺度的海气、陆气耦合作用和大气响应均为延伸期预报提供了重要的可预报性来源。由于数值模式延伸期时段的预报性能与实际业务需求还存在一定距离,基于动力统计相结合和物理统计的延伸期预报方法被广泛应用于业务预报,表现出一定的预报技巧。  相似文献   
10.
Climate change is upon us. While debates continue over how to mitigate emissions, it is evident that many parts of the world will need to adapt to an increasingly unstable climate. However, the persistence of climate denial presents a significant barrier to climate change response; if a future in which the climate has dramatically changed cannot be imagined, there is little motivation to act. Using qualitative interview data, our research investigates community responses to climate change adaptation planning in a coastal region of Australia identified as highly vulnerable to future sea level rise. While the local council engaged in extensive consultation to develop an adaptation plan, community opposition to proposed development changes ultimately resulted in a ‘wait and see’ response. We show how the community’s local understandings of place informed temporalities that led to a practice of climate denial. We outline three processes by which climate denial is socially organised: anchoring the past via historical reference; projecting continuity through a nostalgic lens of managing disaster; and enclosing the present by prioritising existing economic value. We show how these processes result in the social organisation of climate denial, and an inability to plan for a climate changed future.  相似文献   
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