Spatial and temporal distribution of precipitation based on corrected TRMM data around the Hexi Corridor, China     

Tao Zhang  YuanQing He  Jian M  Juan Pang 《寒旱区科学》2014,6(2):0159-0167

Accurate rainfall distribution is difficult to acquire based on limited meteorological stations, especially in remote areas like high mountains and deserts. The Hexi Corridor and its adjacent regions （including the Qilian Mountains and the Alxa Plateau） are typical districts where there are only 30 available rain gauges. Tropical Rainfall Measuring Mission （TRMM） data provide a possible solution. After precision analysis of monthly 0.25 degree resolution TRMM 3B43 data from 1998 to 2012, we find that the correlations between TRMM 3B43 estimates and rain gauge precipitation are significant overall and in each station around the Hexi Corridor; however, the biases of annual precipitation differ in different stations and are seriously overestimated in most of the sites. Thus, Inverse Distance Weighting （IDW） interpolation method was used to rectify TRMM data based on the difference between TRMM 3B43 estimates and rain gauge observations. The results show that rectified TRMM data present more details than rain gauges in remote areas where there are few stations, alt- hough they show high coherence of distribution. Precipitation decreases from southeast to northwest on an annual and seasonal scale. There are three rainfall centers （〉500 mm） including Menyuan, Qilian and Toson Lake, and two low rain- fall centers （〈50 mm） including Dunhuang and Ejin Banner. Meanwhile, precipitation in most of the study area presents an increasing trend; especially in northern Qilian Mountains （〉5 mm/a）, Badain Jaran Desert （〉2 mm/a）, Toson Lake （〉20 mm/a） and Qingtu Lake （〉20 ram/a） which shows a significant increasing trend, while precipitation in Hala Lake （〈-2 mm/a） and Tengger Desert （〈-3 mm/a） demonstrates a decreasing trend.  相似文献   

Zoospore-derived monoecious gametophytes in Undaria pinnatifida (Phaeophyceae)     

李静  逄少军  单体锋  刘峰  高素芹 《中国海洋湖沼学报》2014,32(2):365-371

The annual life cycle of the brown seaweed Undaria pinnatifi da(Harvey)Suringer comprises a macroscopic diploid sporophyte stage and a microscopic haploid gametophyte stage.In 2011,an unusual zoospore-derived monoecious gametophyte isolate(designated as line 10-5-3)of U.pinnatifi da was observed.To understand this phenomenon,a comprehensive screening of eighty-two previously identifi ed male gametophyte cultures,isolated from three randomly selected cultivars(lines 10,7,and 5)was performed.Thirty-six of the isolates developed both antheridia and oogonia on the same fi lamentous fragment in a standard gametogenesis test(SGT: 18°C,60 μmol photons/(m 2·s)).Selfi ng of the monoecious gametophyte or crossing it with a normal male gametophyte both gave rise to morphologically normal sporophytic offspring.However,crossing resulted in a much higher fertilization rate(89.7%).The hybrid and selfed sporophytic offspring were grown to maturity in fl ow tanks at an ambient temperature of 10–18°C over a period of 69 days.Active zoospores were released from both types of mature sporophylls.The majority of these developed into male gametophytes,while 15%–20% developed into the observed monoecious structures on the same fi lament.Using PCR amplifi cation it was found that all the monoecious gametophyte isolates and the sporophytic offspring resulting from the selfi ng and crossing lacked the femalelinked microsatellite sequence(a part of the locus Up-AC-2A8,GenBank accession No.AY738602.1),indicating their male nature.U.pinnatifi da is an invasive species in some regions and the implications of the above fi ndings for this species in nature are briefl y discussed.  相似文献   

苍梧县砂糖桔低温冷害风险区划     

李敬源  钟晓云  叶瑜  潘绍勇  赵伟明 《气象研究与应用》2014,(1):63-66,I0001

通过对苍梧县各个镇低温冷害的分析,找出影响苍梧县砂糖桔生产的4个气候关键因子,通过归一化方法和加权综合评价法分析,利用地理信息系统（GIS）绘制出苍梧县砂糖桔低温冷害风险区划专题图.区划图明确分出苍梧县低温冷害的低风险区、次低风险区、中等风险区、次高风险区和高风险区.在此基础上,针对各风险区域进行了分析与评述,特别指出了防御低温冷害的措施,为苍梧县砂糖桔生产趋利避害和优化布局提供科学决策依据.  相似文献   

南极普里兹湾及其邻近海域水团研究   总被引：3，自引：3，他引：0  

陈红霞  林丽娜  史久新 《海洋学报》2014,36(7):1-8

普里兹湾及其邻近海域是中国南大洋调查研究的传统优势海域与重点区域。围绕夏季表层水、冬季水、陆架水、绕极深层水、南极底层水、普里兹湾底层水、冰架水等研究海区主要水团的特征和分布,总结了前人在南极普里兹湾及其邻近海域基于调查资料开展的水团研究中所取得的成果。研究表明,前人在对陆架水的示性指标界定上,将陆架水是否区分为高盐陆架水和低盐陆架水存在较大争议,在高盐陆架水和普里兹湾底层水的定义上存在重叠;目前尚没有证据表明绕极深层水向南可以伸展到普里兹湾的陆架区域,也没有发现在普里兹湾附近海域生成南极底层水的直接证据。  相似文献   

三个文蛤家系双列杂交设计在两种环境下的配合力及杂种优势分析     

代平  王鸿霞  肖国强  刘保忠 《海洋学报(英文版)》2014,33(10):37-42

A 3×3 complete diallel cross comprising three families of the clam Meretrix meretrix(P1, P2 and P3) was used to determine the combining ability of parental families and heterosis of F1 under indoor and openair environments for growth traits. Analysis of variance for shell length and whole body weight indicated highly significant cross effects, environment effects and the interaction of cross by environment. General combining ability(GCA) and specific combing ability exhibited great variation among crosses and between two environments. Pooled over environments, P2 was the top combiner among the three parental families for both traits studied. The cross of P1 and P3 had the highest SCA. Additionally, significant reciprocal effects were observed. For individual environment, about half of the crossbred combinations showed favorable Mid-parent heterosis(MPH)(1%) for the shell length and whole body weight. Our data has shown that non-additive genetic and reciprocal effects constituted the major sources of genetic variation for both shell length and whole body weight, which indicates that crossbreeding among selective families could further explore the heterotic effects.  相似文献   

Tree mortality in response to climate change induced drought across Beijing,China     

Xiongqing Zhang  Yuancai Lei  Yong Pang  Xianzhao Liu  Jinzeng Wang 《Climatic change》2014,124(1-2):179-190

Tree mortality in response to climate change induced drought has emerged as a global concern. Small changes of tree mortality rates can profoundly affect forest structure, composition, dynamics and ecosystem services such as carbon sequestration. Our analyses of longitudinal data from natural stands (82 plots) in Beijing showed that tree mortality rates have increased significantly over the two decades from 1986 to 2006. In contrast, recruitment rates decreased significantly over this period. The increase in overall mortality rates resulted from an increase in tree deaths dominantly attributed to changes in temperature and precipitation resulting in drier conditions across latitudes, elevations, tree species, and tree sizes. In addition, the results showed that mortality rates of Chinese pine (Pinus tabuliformis) (β ₁ ?=?0.0874) as a result of climate change induce drought were much smaller than oak (Quercus) (β ₁ ?=?0.1583).  相似文献   

Geochemistry,and zircon U–Pb and molybdenite Re–Os geochronology of Jilongshan Cu–Au deposit,southeastern Hubei Province,China     

A‐Juan Pang  Sheng‐Rong Li  M. Santosh  Qing‐Yu Yang  Bao‐Jian Jia  Cheng‐Dong Yang 《Geological Journal》2014,49(1):52-68

The Jilongshan skarn Cu–Au deposit is located at the Jiurui ore cluster region in the southwestern part of the Middle–Lower Yangtze River valley metallogenic belt. The region is characterized by NW‐, NNW‐ and EW‐trending faults and the mineralization occurs at the contact of lower Triassic carbonate rocks and Jurassic granodiorite porphyry intrusions. The intrusives are characterized by SiO₂, K₂O, and Na₂O concentrations ranging from 61.66 to 67.8 wt.%, 3.29 to 5.65 wt.%, and 2.83 to 3.9 wt.%, respectively. Their A/CNK (A/CNK = n(Al₂O₃)/[n(CaO) + n(Na₂O) + n(K₂O)]) ratio, δEu, and δCe vary from 0.77 to 1.17, 0.86 to 1, and 0.88 to 0.96, respectively. The rocks show enrichment in light rare earth elements ((La/Yb)_N = 7.61–12.94) and large ion lithophile elements (LILE), and depletion in high field strength elements (HFSE), such as Zr, Ti. They also display a peraluminous, high‐K calc‐alkaline signature typical of intrusives associated with skarn and porphyry Cu–Au–Mo polymetallic deposits. Laser ablation inductively coupled plasma spectrometry (LA‐ICP‐MS) zircon U–Pb age indicates that the granodiorite porphyry formed at 151.75 ± 0.70 Ma. A few inherited zircons with older ages (677 ± 10 Ma, 848 ± 11 Ma, 2645 ± 38 Ma, and 3411 ± 36 Ma) suggest the existence of an Archaean basement beneath the Middle–Lower Yangtze River region. The temperature of crystallization of the porphyry estimated from zircon thermometer ranges from 744.3 °C to 751.5 °C, and 634.04 °C to 823.8 °C. Molybdenite Re–Os dating shows that the Jilongshan deposit formed at 150.79 ± 0.82 Ma. The metallogeny and magmatism are correlated to mantle–crust interaction, associated with the subduction of the Pacific Plate from the east. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

中国地热研究的进展与展望(1995～2014)          下载免费PDF全文

庞忠和  黄少鹏  胡圣标  赵平  何丽娟 《地质科学》2014,(3):719-727

地热是主要地球物理场之一,地热能是地球的本土能源。李四光在20世纪60年代开创了我国地热科学。到90年代,学科体系基本建立。在过去20年里,我国地热研究得到了进一步深化和拓展。本文从大地热流、岩石圈热结构、地热系统、油气盆地地热、矿山地热、天然气水合物以及气候变化等方面回顾地热研究代表性的创新进展,并对深层地热、海洋地热、环境地热等研究方向作了展望。本文认为,过去20年我国地热研究成果丰硕,国际影响力得到提高,未来发展势头强劲。在经历了由浅入深,从今到古的成长之后,地热研究还将不断拓展领域,为我国地球科学,特别是能源与环境安全做出更大贡献。  相似文献   

山洪预报预警技术研究进展   总被引：5，自引：1，他引：4       下载免费PDF全文

李红霞  覃光华  王欣  缪韧  刘盈斐 《水文》2014,34(5):12-16

山洪预报预警研究是实施山洪灾害防治的重要科学支撑。目前国内外学者对山洪预报预警技术的研究主要集中在山洪预警指标、山洪预报预警模型以及山洪灾害风险分析等方面,本文对山洪预报预警技术相关研究进展进行了总结,并指出未来在山洪灾害监测、山洪预报预警模型研制、多元信息融合技术、结合山洪特点和区划有针对性进行预报预警等方面还应进行更深入的研究。  相似文献   

降雨资料Kriging与IDW插值对比分析—以漓江流域为例   总被引：4，自引：1，他引：3       下载免费PDF全文

范玉洁  余新晓  张红霞  宋美华  NULL 《水文》2014,34(6):61-66

降水空间化信息在很多领域都具有重要意义,而进行空间插值方法形成降水空间化信息是当代较为常用的方式。面对众多的插值方法其插值精度成为我们是否采用的关键,就kirging插值法与IDW(Inverse Distance Weighting)插值进行研究以探讨其插值效果,为此类科学研究提供依据。研究以漓江流域内各气象站点降水统计资料为基础分别采用上述两种方法进行插值处理,通过与预留实测站点比较评判方法的插值效果的优劣。结果表明,多年月平均降水量作为时间步长时,降水丰沛的月份使用kriging插值法较优于IDW插值法,而枯水月份则使用IDW插值法较优于kriging插值法。  相似文献