THERMAL FORCING IMPACTS OF THE EASTERLY VORTEX ON THE EAST-WEST SHIFT OF THE SUBTROPICAL ANTICYCLONE OVER WESTERN PACIFIC OCEAN     

姚秀萍  孙建元 《热带气象学报(英文版)》2016,22(1):51-56

By employing the NCEP/NCAR reanalysis data sets(1 000 to 10 hPa,2.5°× 2.5°),the thermal forcing impacts are analyzed of an easterly vortex(shortened as EV) over the tropical upper troposphere on the quasi-horizontal movement of the Western Pacific Subtropical Anticyclone(shortened as WPS A) during 22-25 June 2003.The relevant mechanisms are discussed as well.It is shown that the distribution and intensity of the non-adiabatic effect near the EV result in the anomalous eastward retreat of the WPSA.The WPSA prefers extending to the colder region,i.e.,it moves toward the region in which the non-adiabatic heating is weakening or the cooling is strengthening.During the WPSA retreat,the apparent changes of non-adiabatic heating illustrate the characteristics of enhanced cooling in the east side of the EV.Meanwhile,the cooling in the west side exhibits a weakened eastward trend,most prominently at 300 hPa in the troposphere.The evidence on the factors causing the change in thermal condition is found:the most important contribution to the heating-rate trend is the vertical transport term,followed in turn by the local change in the heating rate term and the horizontal advection term.As a result,the atmospheric non-adiabatic heating generated by the vertical transport and local change discussed above is mainly connected to the retreat of the WPSA.  相似文献   

气象、农业和水文干旱之间关联性分析     

胡彩虹  赵留香  王艺璇 《气象与环境科学》2016,39(4):1-6

干旱具有发生频率高、持续时间长、波及范围广的特点。而干旱预报为科学地进行防旱抢险提供了决策支持。选取反映不同类型干旱的指标,即标准化降雨指标(SPI)、标准化土壤湿度指标(SSWI)和标准化径流指标(SRI),通过SWAT模型和带有时滞的灰色关联判断了各干旱之间的时滞。以陆浑水库控制流域为例进行了分析,结果表明:SWAT模型在该流域有很好的适用性,1975—2009年间发生各类干旱的次数在增加,且变率上从气象干旱、农业干旱到水文干旱有所增加,同时不同类型干旱之间表现出了一定的时滞关系,气象干旱对农业干旱的响应时间为1个月;水文干旱对气象干旱的响应时间为4个月;水文干旱对农业干旱的响应时间为2个月。  相似文献   

CINRAD/SA(B)发射机高压打火组件级故障诊断     

潘新民  白水成  崔炳俭 《气象科技》2016,44(2):184-191

新一代天气雷达技术保障中,发射机高压负载打火导致的综合故障的诊断和定位是比较复杂的,具有故障点多、故障涉及组件多、故障修复时间长等特点,是新一代天气雷达故障维修的难点。依据发射机高压控制和监控信号流程,提出了发射机高压打火组件级故障诊断流程。通过发射机组件级故障诊断流程快速修复发射机高压负载打火综合故障过程,表明发射机高压打火组件级故障诊断流程在雷达维修中具有规范化和适用性维修效果,进一步显示出故障分析诊断流程在新一代天气雷达技术保障中的重要作用。  相似文献   

Comparative assessment of Japan's long-term carbon budget under different effort-sharing principles     

Takeshi Kuramochi  Jusen Asuka  Hanna Fekete  Kentaro Tamura  Niklas Höhne 《Climate Policy》2016,16(8):1029-1047

This article assesses Japan's carbon budgets up to 2100 in the global efforts to achieve the 2?°C target under different effort-sharing approaches based on long-term GHG mitigation scenarios published in 13 studies. The article also presents exemplary emission trajectories for Japan to stay within the calculated budget.

The literature data allow for an in-depth analysis of four effort-sharing categories. For a 450?ppm CO₂e stabilization level, the remaining carbon budgets for 2014–2100 were negative for the effort-sharing category that emphasizes historical responsibility and capability. For the other three, including the reference ‘Cost-effectiveness’ category, which showed the highest budget range among all categories, the calculated remaining budgets (20th and 80th percentile ranges) would run out in 21–29 years if the current emission levels were to continue. A 550?ppm CO₂e stabilization level increases the budgets by 6–17 years-equivalent of the current emissions, depending on the effort-sharing category. Exemplary emissions trajectories staying within the calculated budgets were also analysed for ‘Equality’, ‘Staged’ and ‘Cost-effectiveness’ categories. For a 450?ppm CO₂e stabilization level, Japan's GHG emissions would need to phase out sometime between 2045 and 2080, and the emission reductions in 2030 would be at least 16–29% below 1990 levels even for the most lenient ‘Cost-effectiveness’ category, and 29–36% for the ‘Equality’ category. The start year for accelerated emissions reductions and the emissions convergence level in the long term have major impact on the emissions reduction rates that need to be achieved, particularly in the case of smaller budgets.

Policy relevance

In previous climate mitigation target formulation processes for 2020 and 2030 in Japan, neither equity principles nor long-term management of cumulative GHG emissions was at the centre of discussion. This article quantitatively assesses how much more GHGs Japan can emit by 2100 to achieve the 2?°C target in light of different effort-sharing approaches, and how Japan's GHG emissions can be managed up to 2100. The long-term implications of recent energy policy developments following the Fukushima nuclear disaster for the calculated carbon budgets are also discussed.  相似文献   

硫酸参与的长江流域岩石化学风化速率与大气CO2消耗   总被引：4，自引：0，他引：4  

张连凯  覃小群  刘朋雨  黄奇波 《地质学报》2016,90(8):1933-1943

流域的岩石化学风化过程是全球碳循环中的重要环节。以往的流域水化学碳汇通量估算大多是基于碳酸的风化作用。而实际上,硫酸和碳酸一样,也参与了流域碳元素的地球化学循环,从而对全球碳循环过程产生影响。长江流域水体近几年出现酸化现象,大部分河段SO42-和Ca2+含量增高,其对应的岩石风化过程和大气CO2消耗速率也发生变化。文章对长江干流及主要支流2013年不同季节的离子组成进行监测,利用水化学平衡法和Galy估算模型,对长江流域岩石化学风化速率和CO2消耗通量进行了估算,对硫酸参与下的长江流域岩石风化和碳循环过程进行了分析。结果表明,长江流域水体离子主要来源于硅酸盐岩风化和碳酸盐岩风化。其中碳酸盐岩风化对河水离子贡献率为92%。在硅酸盐岩广泛分布的赣江流域,碳酸盐岩风化离子贡献也达85%。分析表明,硫酸参与了长江流域的岩石风化过程,对水体中离子产生一定影响。硫酸的参与加快了碳酸盐岩的化学风化速率,平均提高约30%,但是使流域大气CO2消耗速率降低。在不考虑蒸发岩溶蚀作用下,平均从516×103 mol/km2·a降至356×103 mol/km2·a,降低约31%。在各支流中,硫酸对乌江流域碳酸盐岩的风化和碳循环的影响最大,而对雅砻江的影响最小,这与乌江流域的含煤地层、矿床硫化物及大气酸沉降有关。  相似文献   

广西官村岩溶溪流中生物地球化学控制的DIC和NO3-昼夜变化研究     

张陶  蒲俊兵  袁道先  李建鸿 《地质学报》2016,90(8):1965-1976

为了解岩溶区控制溪流中溶解无机碳(DIC)和NO_3~-昼夜变化的生物地球化学过程以及DIC和NO_3~-日变化量,于2014-07-22~2014-07-24期间,在广西壮族自治区融安县官村溪流中包括地下河出口(CK)和下游雷崖村(LY)设置两个监测点同时对水体物理化学参数以及C、N同位素(δ~(13) CDIC、δ~(15) N-NO_3~-和δ~(18) O-NO_3~-)展开了为期2d的高分辨率昼夜监测采样工作。结果发现CK点各物理化学参数没有表现出昼夜变化,但是LY点Ca2+、DIC以及PCO2表现出明显的昼夜变化规律,即白天下降夜间上升且与DO和pH表现出明显的负相关关系。相对于CK点,在白天水生光合生物光合作用导致LY点DIC下降的同时δ~(13) CDIC上升,而在夜间呼吸作用导致LY点DIC上升的同时δ~(13) CDIC下降且部分时间段要低于CK点δ~(13) CDIC值。溪流中的NH4+在监测期间基本上都在下降而NO_3~-离子在夜间和上午时间段都在上升,δ~(15) N-NO_3~-却表现出下降的趋势,且比较接近δ~(15) N-NO_3~-初始值,而NO_3~-离子在下午时间段出现下降的趋势。结果表明溪流中DIC昼夜变化主要受到水生植物的光合作用和呼吸作用控制,且通过质量平衡方程计算得知溪流中由于光合作用吸收无机碳而转为有机碳的量为0.94kgC/d,这部分有机碳可以形成相对长期稳定的自然C汇。溪流在夜间和上午时间段发生了N的硝化作用,增长量为2.08kgN/d,但在下午时间段(12:00~18:00)发生了N的同化作用,损失量为0.42kgN/d。溪流输出的NO_3~--N的量为1.66kgN/d,表明在富碳、富钙的岩溶溪流中,有利于水生光合生物的生长,促进N的同化作用的发生,从而减少溪流输出NO_3~--N的量,说明岩溶区溪流N的生物地球化学过程可能在昼夜尺度上改变水质。  相似文献   

鄂尔多斯盆地北部直罗组有机质特征及与铀成矿关系   总被引：2，自引：0，他引：2  

侯惠群  李言瑞  刘洪军  韩绍阳  王贵  白云生  吴迪  吴柏林 《地质学报》2016,90(12):3367-3374

本文研究了鄂尔多斯盆地典型铀矿床的有机质与铀成矿的关系。探讨了煤屑的赋存状态、煤质特征及成熟度,认为煤屑的演化程度均较低,处于低成熟阶段,有利于对铀的吸附。总体上看煤质有机质和铀矿化关系密切,铀含量与煤屑含量呈正相关关系,对铀矿物为吸附态形式。通过对该区油气包裹体的研究认为,该区存在多期次的成岩方解石胶结过程,并伴随多期次的油气包裹体发育,尤以晚期的胶结方解石矿物中存在丰富的晚期油气包裹体。研究认为晚期可能发生过油、气的运移和聚集,铀矿床的形成与赋矿砂岩中有机流体或还原性气体的充注和络合作用密切相关,因而这些丰富的有机流体和还原性气体对于铀的富集沉淀具有重要意义。  相似文献   

Petrogenesis and geodynamic evolution of the Kajan Neogene subvolcanic rocks,Nain, Central Iran     

《Chemie der Erde / Geochemistry》2016,76(4):567-578

Kajan subvolcanic rocks in the Urumieh–Dokhtar magmatic arc (UDMA), Central Iran, form a Late Miocene-Pliocene shallow-level intrusion. These subvolcanics correspond to a variety of intermediate and felsic rocks, comprising quartz diorite, quartz monzodiorite, tonalite and granite. These lithologies are medium-K calc-alkaline, with SiO₂ (wt.%) varying from 52% (wt.%) to 75 (wt.%). The major element chemical data also show that MgO, CaO, TiO₂, P₂O₅, MnO, Al₂O₃ and Fe₂O₃ define linear trends with negative slopes against SiO₂, whilst Na₂O and K₂O are positively correlated with silica. Contents of incompatible trace elements (e.g. Ba, Rb, Nb, La and Zr) become higher with increasing SiO₂, whereas Sr shows an opposite behaviour. Chondrite-normalized multi-element patterns show enrichment in LILE relative to HFSE and troughs in Nb, P and Ti. These observations are typical of subduction related magmas that formed in an active continental margin. The Kajan rocks show a strong affinity with calc-alkaline arc magmas, confirmed by REE fractionation (La_N/Yb_N = 4.5–6.4) with moderate HREE fractionation (Sm_N/Yb_N = 1.08–1.57). The negative Eu anomaly (Eu/Eu* <1), the low to moderate Sr content (< 400 ppm) and the Dy/Yb values reflect plagioclase and hornblende (+- clinopyroxene) fractionation from a calc-alkaline melt Whole–rock Sr and Nd isotope analyses show that the ⁸⁷Sr/⁸⁶Sr initial ratios vary from 0.704432 to 0.705989, and the ¹⁴³Nd/¹⁴⁴Nd initial ratios go from 0.512722 to 0.512813. All the studied samples have similar Sr-Nd isotopes, indicating an origin from a similar source, with granite samples that has more radiogenic Sr and low radiogenic Nd isotopes, suggesting a minor interaction with upper crust during magma ascent. The Kajan subvolcanic rocks plot within the depleted mantle quadrant of the conventional Sr-Nd isotope diagram, a compositional region corresponding to mantle-derived igneous rocks.  相似文献   

Landscape pattern and transition under natural and anthropogenic disturbance in an arid region of northwestern China     

《International Journal of Applied Earth Observation and Geoinformation》2016

There is a pressing need to determine the relationships between driving variables and landscape transformations. Human activities shape landscapes and turn them into complex assemblages of highly diverse structures. Other factors, including climate and topography, also play significant roles in landscape transitions, and identifying the interactions among the variables is critical to environmental management. This study analyzed the configurations and spatial-temporal processes of landscape changes from 1998 to 2011 under different anthropogenic disturbances, identified the main variables that determine the landscape patterns and transitions, and quantified the relationships between pairs of driver sets. Landsat images of Baicheng and Tekes from 1998, 2006 and 2011 were used to classify landscapes by supervised classification. Redundancy analysis (RDA) and variation partitioning were performed to identify the main driving forces and to quantify the unique, shared, and total explained variation of the sets of variables. The results indicate that the proportions of otherwise identical landscapes in Baicheng and Tekes were very different. The area of the grassland in Tekes was much larger than that of the cropland; however, the differences between the grassland and cropland in Baicheng were not as pronounced. Much of the grassland in Tekes was located in an area that was near residents, whereas most of the grassland in Baicheng was far from residents. The slope, elevation, annual precipitation, annual temperature, and distance to the nearest resident were strong driving forces influencing the patterns and transitions of the landscapes. The results of the variation partitioning indicated complex interrelationships among all of the pairs of driver sets. All of the variable sets had significant explanatory roles, most of which had both unique and shared variations with the others. The results of this study can assist policy makers and planners in implementing sustainable landscape management and effective protection strategies.  相似文献   

Retrieval of effective leaf area index (LAIe) and leaf area density (LAD) profile at individual tree level using high density multi-return airborne LiDAR     

《International Journal of Applied Earth Observation and Geoinformation》2016

As an important canopy structure indicator, leaf area index (LAI) proved to be of considerable implications for forest ecosystem and ecological studies, and efficient techniques for accurate LAI acquisitions have long been highlighted. Airborne light detection and ranging (LiDAR), often termed as airborne laser scanning (ALS), once was extensively investigated for this task but showed limited performance due to its low sampling density. Now, ALS systems exhibit more competing capacities such as high density and multi-return sampling, and hence, people began to ask the questions like—“can ALS now work better on the task of LAI prediction?” As a re-examination, this study investigated the feasibility of LAI retrievals at the individual tree level based on high density and multi-return ALS, by directly considering the vertical distributions of laser points lying within each tree crown instead of by proposing feature variables such as quantiles involving laser point distribution modes at the plot level. The examination was operated in the case of four tree species (i.e. Picea abies, Pinus sylvestris, Populus tremula and Quercus robur) in a mixed forest, with their LAI-related reference data collected by using static terrestrial laser scanning (TLS). In light of the differences between ALS- and TLS-based LAI characterizations, the methods of voxelization of 3D scattered laser points, effective LAI (LAIe) that does not distinguish branches from canopies and unified cumulative LAI (ucLAI) that is often used to characterize the vertical profiles of crown leaf area densities (LADs) was used; then, the relationships between the ALS- and TLS-derived LAIes were determined, and so did ucLAIs. Tests indicated that the tree-level LAIes for the four tree species can be estimated based on the used airborne LiDAR (R² = 0.07, 0.26, 0.43 and 0.21, respectively) and their ucLAIs can also be derived. Overall, this study has validated the usage of the contemporary high density multi-return airborne LiDARs for LAIe and LAD profile retrievals at the individual tree level, and the contribution are of high potential for advancing forest ecosystem modeling and ecological understanding.  相似文献