Controls on seasonal variations of silicate weathering and CO2 consumption in two river catchments on the NE Tibetan Plateau     

《Journal of Asian Earth Sciences》2013

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Soil organic matter transport along an sub-Arctic river–sea transect     

《Organic Geochemistry》2012

Bacteriohopanepolyols (BHPs) and glycerol dialkyl glycerol tetraethers (GDGTs) have potential as soil-tracing biomarkers for the extensive shelves of the Arctic Ocean. In this work these biomarkers were analysed in surface sediments along a well characterised sub-Arctic transect in the northernmost Baltic Sea from the Kalix River to the central Bothnian Bay to assess their environmental behaviour and potential for tracing the contribution of soil in this type of system. There was a high BHP diversity and enhanced total BHP concentration in the estuarine sediments, whereas a much less diverse pattern could be observed in the open bay with lower total BHP concentration. In addition, both soil marker BHPs (adenosylhopanes) and branched GDGTs were substantially more abundant in the estuarine than the open bay sediments.The $R_{\text{soil}}^{\prime }$ index, based on the R_soil index minus the contribution from the methylated soil marker BHPs, is suggested as a new approach for tracing soil derived organic matter (OM) in the (sub)-Arctic region. The index decreased along the transect in an off-river direction, correlating strongly with both the branched and isoprenoid tetraether (BIT) index and the stable carbon isotopic composition of the sedimentary organic carbon. These field results indicate that both the $R_{\text{soil}}^{\prime }$ and the BIT indices have potential for tracing soil derived OM in sub-Arctic to Arctic waters.  相似文献   

基于“黑格比”和“灿都”台风期间湍流数据的曳力系数和动力粗糙度长度参数化研究*     

张小华  毕雪岩  高志球  刘长炜  彭文武  曾智华  杨楠  李煜斌 《热带海洋学报》2021,40(2):1-6

海面的曳力系数和空气动力学粗糙度长度是计算海气动量、感热和水汽通量交换必需的参数。基于在“黑格比”和“灿都”台风期间收集的涡动相关系统观测数据, 文章研究了10m风速和摩擦速度之间、10m风速和曳力系数之间、以及10m风速和动力粗糙度长度之间的参数化关系。结果表明: 曳力系数和摩擦速度及10m风速之间存在抛物线关系, 动力粗糙度长度与摩擦速度及10m风速之间存在自然指数关系; 临界摩擦速度为0.83m·s^-1, 临界10m级风速为23.69m·s^-1。  相似文献   

Content and distribution of trace metals in surface sediments from the northern Bering Sea,Chukchi Sea and adjacent Arctic areas     

《Marine pollution bulletin》2012,64(5-12):523-527

Concentrations of trace metals (Zn, Cr, Cu, V, Cd and Pb), total organic carbon (TOC), black carbon (BC) and their granulometry were examined in 25 surface sediment samples from the northern Bering Sea, Chukchi Sea and adjacent areas. Trace metal concentrations in the sediments varied from 21.06–168.21 mg kg⁻¹ for Zn, 8.91–46.94 mg kg⁻¹ for Cr, 2.69–49.39 mg kg⁻¹ for Cu, 32.46–185.54 mg kg⁻¹ for V, 0.09–0.92 mg kg⁻¹ for Cd, and 0.95–15.25 mg kg⁻¹ for Pb. The geoaccumulation index (I_geo) indicated that trace metal contamination (Zn and Cd) existed in some stations of the study area. The distribution of grain size plays an important role in influencing the distribution of trace metals (Zn, Cr, Cu, V, and Pb) in sediments from the Chukchi Sea and adjacent areas.  相似文献   

曹妃甸工业区空气污染来源及其对周边地区污染贡献的数值模拟研究     

李欣怡  向伟玲  陈学舜  朱莉莉  王自发  杨文夷 《气候与环境研究》2019,24(4):469-481

为了深入研究曹妃甸工业区的建立和大型工业企业的迁入对京津冀地区空气质量的影响,利用嵌套网格空气质量预报模式系统NAQPMS(Nested Air Quality Prediction Modeling System)研究该工业区和周边地区在2016年秋、冬季空气质量状况,并对PM2.5(空气动力学当量直径小于等于2.5μm的颗粒物,即细颗粒物)来源与区域输送进行分析。结果表明:模式能很好地再现气象要素和污染物浓度分布特征;曹妃甸地区本地排放在1月和10月的月均贡献分别为17.8%和25.8%。当空气质量为优良时,曹妃甸地区PM2.5主要受短距离周边传输影响,唐山和天津贡献率之和达23%～53%;当空气出现轻度及以上污染时,曹妃甸地区PM2.5浓度主要受到长距离输送的影响,河北中南部和山东地区贡献之和达40%～50%。曹妃甸工业园区排放对周边地区PM2.5浓度贡献相对较小,对唐山和天津地区贡献为3%～7%,对京津冀地区其他城市PM2.5浓度贡献可忽略不计。空气质量转差时,曹妃甸、北京和天津地区PM2.5中一次排放占比相较于空气质量优良时明显下降,二次生成的无机盐类和二次有机气溶胶贡献率增加;曹妃甸地区10月二次生成硫酸盐贡献率较1月明显增加,月均贡献率为22%。因此,在致力于削减京津冀地区PM2.5一次排放的同时,对SO2、NOx等进行控制,能有效改善该地区空气质量。  相似文献   

风云三号气象卫星红外分光计探测大气CO2浓度的通道敏感性分析     

戴铁  石广玉  漆成莉  徐娜  张兴赢  杨溯 《气候与环境研究》2011,16(5):577-585

依据红外分光计（InfraRed Atmospheric Sounder,IRAS）光谱通道特征,发展了基于IRAS的大气辐射传输计算模式。以大气分子吸收光谱数据集（HIgh resolution TRANsmission,HITRAN） 2004为初始谱线输入资料,利用该模式模拟计算IRAS在CO2 吸收带的10个通道辐射率测值对CO2浓度变化的响应,并对比了其与大气温度和水汽、O3等气体浓度误差对辐射率测值的影响,探讨了利用风云三号气象卫星探测大气CO2浓度的可行性。结果表明,IRAS的通道4最适于用来监测大气CO2浓度的变化,当CO2体积混合比浓度变化在10×10-6时,对应的辐射率变化同仪器等效噪声辐射率相当,所以IRAS在理想状态下,最高可分辨的大气CO2浓度变化约为10×10-6。  相似文献   

基于能见度及AOD数据的北京市PM2.5浓度的反演     

杨颖川  葛宝珠  郝赛宇  徐丹卉  刘颖  甘璐  王自发 《气候与环境研究》2020,25(5):521-530

选择北京市为研究地区,对2014～2017年AERONET（Aerosol Robotic Network）提供的CE-318太阳光度计440 nm波段反演的气溶胶光学厚度（AOD）进行风速订正,对订正后 AOD 日均数据与同期地面监测站PM2.5日均浓度数据做季节相关性分析并建立回归模型。又引入能见度因子并利用广义差分法构建2015～2017年北京市AOD与PM2.5浓度、能见度的三元回归模型,最后将2014年数据分为污染日和非污染日分别进行模型检验。结果表明:AOD与PM2.5浓度存在显著的线性正相关性,且存在季节性差异,夏季相关性最强、秋季次之、春季和冬季最低。引入能见度因子并消除自相关后,四季的模型相对误差均显著减小,模型拟合优度显著提高。检验结果为四季整体的平均相对误差在21%～31%范围内,与前人的结果相比拟合曲线的准确性得到了明显地提高。且模型对低PM2.5浓度日的模拟效果较好,对于高PM2.5浓度日的模拟效果较差。本研究对构建北京地区PM2.5浓度长期的历史数据具有重要的科学意义。  相似文献   

Erosion history of the Tibetan Plateau since the last interglacial: constraints from the first studies of cosmogenic 10Be from Tibetan bedrock     

《Earth and Planetary Science Letters》2004,217(1-2):33-42

The cosmogenic ¹⁰Be exposure histories of in situ bedrock surfaces from the Tibetan Plateau indicate low erosion rates of <30 mm/ka in southern and central Tibet during the last interglacial–glacial cycle that contrast strongly with unusually rapid erosion rates (60–2000 mm/ka) for Kunlun in northern Tibet during the Holocene, comparable with published values from the Himalaya. By comparing apatite fission-track ages with cosmogenic data, erosion rates in southern Tibet appear to be decelerating since the Miocene, whereas in the Kunlun, erosion rates have accelerated over the same timescale. Such secular changes suggest that the southern and central regions of the plateau had formed their present flat relief by the Pleistocene. Unusually high erosion rates along the northern margin of the plateau may reflect intense tectonic activity during the Holocene. These findings indicate that over much of the high plateau erosion rates are exceptionally low, and therefore the sources of detritus carried by the great Asian rivers that rise in Tibet lie overwhelmingly in bedrocks at lower altitudes. This study illustrates the potential of cosmogenic studies for unraveling the most recent phase of the erosion/exhumation history of orogenic belts that cannot be resolved by either Ar-isotope or fission-track thermochronometers.  相似文献   

The influence of physicochemical parameters on bioavailability and bioaccessibility of heavy metals in sediments of the intertidal zone of Asaluyeh region,Persian Gulf,Iran     

《Chemie der Erde / Geochemistry》2019,79(1):178-187

In this research, we have worked on the evaluation of heavy metal contamination in the sediments taken from the intertidal zone of Asaluyeh region using Modified Community Bureau of Reference sequential extraction method (mBCR), the simplified bioaccessibility extraction test (SBET), and calculated enrichment factor (EF). Also, potential influencing factors including sediment characteristics that may affect the heavy metals bioavailability and bioaccessibility were investigated. mBCR extraction analysis indicated that among the metals, Mn, Zn, V, Cu, and Cd exhibit relatively higher mobility, while Ti, Pb, Cr, and Ni occur mainly in the residual fractions. Based on the mean values, the bioaccessibility of metals decreased in the order: Mn (50.01%)>Cd (46.26%)>Zn (14.61%)>V (13.97%)>Pb (10.88%)>Ni (9.2%)>Ti (8.43%)>Cr (6.66%)>Cu (6.23%). The obtained results from the principal component analysis (PCA), EF and mBCR extraction showed that most anthropogenic-derived metals with higher solubility are more bioaccessible compared to those of natural origin. Multiple linear regression analysis demonstrated that the main physicochemical variables of the sediment influencing the bioaccessibility of metals include cation exchange capacity (CEC), pH, and particle size fraction.  相似文献   

Extracting ideology from policy: Analysing the social construction of conservation priorities in the Coral Triangle region     

《Marine Policy》2017

This study presents an analysis of marine resource management activities designed to ameliorate concerns over fish stocks, food and livelihood insecurity in the coastal Asia Pacific region, with a specific focus on the area encompassed by the Coral Triangle Initiative on Coral Reefs, Fisheries and Food Security (CTI-CFF). Firstly, the study explores how the CTI-CFF framing of food insecurity as symptomatic of economic deficiencies at the household level reflects the broader neoliberal conservation agenda driving the CTI-CFF and serves to legitimate the latter as the natural authority for intervention. Secondly, the paper uses an example of local level fishery management to demonstrate how the logic of neoliberalism translates to regulations which fail to recognise social and political complexities confronting fishers, thereby exacerbating the precarity of food and livelihood security in these communities. Thirdly, the paper contrasts the Western scientific emphasis on maintaining food security through managing coral reef fisheries with evidence from Indonesia and the Philippines which demonstrates the much larger contribution from pelagic fisheries and aquaculture to food security. The paper concludes with a call for research and aid-funded interventions on fishery management, livelihoods and food security to better reflect the needs of coastal people in the Asia-Pacific region, rather than the values commonly espoused by Western scientists and conservationists.  相似文献