Present and projected degree days in China from observation,reanalysis and simulations   总被引：1，自引：0，他引：1  

Qinglong You  Klaus Fraedrich  Frank Sielmann  Jinzhong Min  Shichang Kang  Zhenming Ji  Xiuhua Zhu  Guoyu Ren 《Climate Dynamics》2014,43(5-6):1449-1462

Degree days are usually defined as the accumulated daily mean temperature varying with the base temperature, and are one of the most important indicators of climate changes. In this study, the present-day and projected changes of four degree days indices from daily mean surface air temperature output simulated by Max Planck Institute, Earth Systems Model of low resolution (MPI-ESM-LR) model are evaluated with the high resolution gridded-observation dataset and two modern reanalyses in China. During 1979–2005, the heating degree days (HDD) and the numbers of HDD (NHDD) have decreased for observation, reanalyses (ERA-Interim and NCEP/NCAR) and model simulations (historical and decadal experiments), consistent with the increasing cooling degree days (CDD) and the numbers of CDD (NCDD). These changes reflect the general warming in China during the past decades. In most cases, ERA-Interim is closer to observation than NCEP/NCAR and model simulations. There are discrepancies between observation, reanalyses and model simulations in the spatial patterns and regional means. The decadal hindcast/forecast simulation performance of MPI-ESM-LR produce warmer than the observed mean temperature in China during the entire period, and the hindcasts forecast a trend lower than the observed. Under different representative concentration pathway (RCP) emissions scenarios, HDD and NHDD show significant decreases, and CDD and NCDD consistently increase during 2006–2100 under RCP8.5, RCP4.5 and RCP2.6, especially before the mid-21 century. More pronounced changes occur under RCP8.5, which is associated with a high rate of radiative forcing. The 20th century runs reflect the sensitivity to the initial conditions, and the uncertainties in terms of the inter-ensemble are small, whereas the long-term trend is well represented with no differences among ensembles.  相似文献   

小石头山金矿地质特征及矿床成因     

周丹 《四川地质学报》2014,(2):200-203

小石头山金矿位于川北阿坝藏族羌族自治州,该矿处于"若尔盖中间地块"西南部"阿坝复理石地体褶皱带"范围内,矿体产于印支晚期花岗闪长岩体内、外接触带上。矿体主要受张裂型矿化裂隙、张剪性复合型矿化裂隙和破碎带型矿化裂隙控制,是较为典型的构造蚀变岩型金矿。  相似文献   

新疆赛里木湖的湖滩岩特征、时代及其对 MIS3阶段湖面变化的指示意义   总被引：3，自引：0，他引：3  

徐胜利  吴中海  李跃华  赵希涛  张克旗  马志邦  马丹  田婷婷 《地质力学学报》2014,20(2):174-184

在对西天山赛里木湖盆地进行第四纪地质调查与5万填图基础上,发现沿该湖泊的不同湖岸阶地上都不同程度地发育了可指示湖面变化的湖滩岩。水准测量结果表明,典型的湖滩岩最常见于高出现今湖面7.1~9.4 m和33.4~39.4 m的低、高两级湖积台地上。对湖滩岩样品进行岩石学和矿物学研究进一步揭示,湖滩岩主要由内碎屑、藻团块、陆源碎屑、胶结物和填隙物等构成,胶结物主要为亮晶方解石,夹少量文石,表明赛里木湖周边的湖滩岩为典型的方解石胶结砂屑砾屑岩。湖滩岩样品的U系年代测试结果表明,低、高两级台地上的湖滩岩主要形成于距今24.8±1.5 ka至27.6±1.5 ka和55.4±3.8 ka的晚更新世晚期,大致对应末次冰期间冰阶MIS3阶段早期和末期的相对暖湿气候阶段。湖滩岩及其测年结果指示,赛里木湖最近一期最高湖面出现在距今55.4 ka左右末次间冰阶早期,其后由于气候的干旱化,湖面整体处于逐步下降过程,在相对暖湿期间经历了多次湖面相对稳定期并形成湖滩岩。  相似文献   

The influence of irrigation and Wuliangsuhai Lake on groundwater quality in eastern Hetao Basin,Inner Mongolia,China     

Dongnan Zhu  M. Cathryn Ryan  Biao Sun  Changyou Li 《Hydrogeology Journal》2014,22(5):1101-1114

Geochemical and isotopic characterization of groundwater and lake-water samples were combined with water and total dissolved solids balances to evaluate sources of groundwater quality deterioration in eastern Hetao Basin, Inner Mongolia, China. Groundwater quality is poor; 11 of 13 wells exceed drinking-water guidelines for at least one health-based parameter and all wells exceed aesthetic guidelines. The well water is largely derived from Yellow River irrigation water. Notably high uranium concentrations in the Yellow River, relative to world rivers, suggest groundwater uranium and other trace elements may originate in the river-derived irrigation water. Complex hydrostratigraphy and spatial variation in groundwater recharge result in spatially complex groundwater flow and geochemistry. Evapotranspiration of irrigation water causes chloride concentration increases of up to two orders of magnitude in the basin, notably in shallow groundwater around Wuliangsuhai Lake. In addition to evapotranspiration, groundwater quality is affected by mineral precipitation and dissolution, silicate weathering, and redox processes. The lake-water and TDS balances suggest that a small amount of discharge to groundwater (but associated with very high solute concentrations) contributes to groundwater salinization in this region. Increasing salinity in the groundwater and Wuliangsuhai Lake will continue to deteriorate water quality unless irrigation management practices improve.  相似文献   

Stratigraphy and tectonics of a time-transgressive ophiolite obduction onto the eastern margin of the Pelagonian platform from Late Bathonian until Valanginian time,exemplified in northern Evvoia,Greece     

Rudolph Scherreiks  Guillermo Meléndez  Marcelle BouDagher-Fadel  Georgia Fermeli  Dan Bosence 《International Journal of Earth Sciences》2014,103(8):2191-2216

The obduction of an ophiolite sheet onto the eastern Pelagonian carbonate platform complex of the Hellenides began during the Late Bathonian and ended with the final emplacement of the ophiolite during Valanginian time. The early stages of obduction caused subaerial exposure of the platform, recorded by an unconformity of Callovian age, which is marked by laterites overlying folded and faulted, karstic substrates. The laterites have distinct ophiolitic geochemical signatures, indicating that emergent ophiolite had been undergoing lateritic weathering. This unconformity coincides with widespread western Tethyan, Callovian gaps, indicating that the obduction in the Hellenides was probably related to far-reaching plate tectonic processes. Resumed gravitational pull and rollback of the subducted, oceanic leading edge of the temporarily exposed ophiolite. Platform drowning continued into Tithonian–Valanginian time, documented initially by reefal carbonates and then by below-CCD, carbonate-free radiolarian cherts and shales. Subsequently, siliciclastic turbidites, which apparently originated from uplifted Variscan basement, were deposited together with and over the radiolarite as the ophiolite nappe sheet advanced. The nappe substrate underwent tectonic deformations of varying intensity, while polymictic mélange and syntectonic sedimentary debris accreted beneath the ophiolite and at the nappe front. The provenience of the ophiolite nappe complexes of northern Evvoia most probably has to be looked for in the Vardar ocean.  相似文献   

黔西地区构造变形特征及其煤层气地质意义   总被引：1，自引：0，他引：1  

窦新钊  ;姜波  ;张文永  ;朱文伟  ;俞显忠  ;胡广青 《中国煤炭地质》2014,(8):54-59

黔西地区处于特提斯与滨太平洋两个构造域的交接地带,多期性质不同的构造作用形成了现今错综复杂的构造变形特征。根据构造变形的差异,可划分为织金-纳雍NE向构造变形区、水城-紫云NW向构造变形区和黔西南复杂构造变形区。在野外地质的基础上,结合微观变形特征和矿物流体包裹体测试分析,认为黔西地区构造变形属于上地壳低温-中低温环境下的脆性-脆韧性变形;由于黔西地区基底构造相对稳定,成煤期后断块内部变形较弱,煤储层形成了一定程度的构造裂隙,有助于渗透率的提高,煤层气勘探开发前景良好。  相似文献   

新郑矿区地热资源潜能分析与保护建议     

朱永飞  ;徐连利  ;景学建  ;樊振丽  ;石勇丽 《中国煤炭地质》2014,(9):43-48

基于新郑矿区以平均每年0.0813×108m3的涌水量向地表排放热水,造成的地热资源损失和污染环境的现实,在分析地温地质条件基础上,利用热储资源量公式、卡明斯基公式和弹性储存量公式,分别计算了矿山开采前和开采后不同类型地热资源量,并对当前矿区地热潜能进行了评估。在此基础上,提出了选择煤层底板加固技术,保持岩溶裂隙水一定的水位、减少地下水排放和利用识别模型,选择适宜区段作为地热资源开采区,以调减矿山日常的排水量,尽可能维持渗流场基本不变,进而提高热储的潜能,实现节能减排,达到保护与利用地热资源的效果的建议。  相似文献   

Predicting lake water quality responses to load reduction: a three-dimensional modeling approach for total maximum daily load   总被引：2，自引：0，他引：2  

Z. Wang  R. Zou  X. Zhu  B. He  G. Yuan  L. Zhao  Y. Liu 《International Journal of Environmental Science and Technology》2014,11(2):423-436

Water quality restoration efforts often suffer the risk of ineffectiveness and failure due to lack of quantitative decision supports. During the past two decades, the restoration of one of China’s most heavily polluted lakes, Lake Dianchi, has experienced costly decision ineffectiveness with no detectable water quality improvement. The governments are planning to invest tremendous amount of funds in the next 5 years to continue the lake restoration process; however, without a quantitative understanding between the load reduction and the response in lake water quality, it is highly possible that these planned efforts would suffer the similar ineffectiveness as before. To provide scientifically sound decision support for guiding future load reduction efforts in Lake Dianchi Watershed, a sophisticated quantitative cause-and-effect response system was developed using a three-dimensional modeling approach. It incorporates the complex three dimensional hydrodynamics, fate and transport of nutrients, as well as nutrient-algae interactions into one holistic framework. The model results show that the model performs well in reproducing the observed spatial pattern and temporal trends in water quality. The model was then applied to three total maximum daily load scenarios and two refined restoration scheme scenarios to quantify phytoplankton responses to various external load reduction intensities. The results show that the algal bloom in Lake Dianchi responds to load reduction in a complex and nonlinear way, therefore, it is necessary to apply the developed system for future load reduction and lake restoration schemes for more informed decision making and effective management.  相似文献   

Estimates of potential nitrate reductase activity in sediments: comparisons of two incubation methods and four inhibitors     

Jian-gang Han  Long-shuai Dou  Yong-li Zhu  Ping-ping Li 《Environmental Earth Sciences》2014,71(1):419-425

Sediment samples, collected from a large shallow lake, Taihu, China, were incubated in two conditions (with and without air extraction) with regard to four soil enzyme’s inhibitors (dry and moist heat sterilizations, chloramphenicol and toluene) to estimate the potential nitrate reductase (Nar) activities. The objectives of paper were to define (1) whether to exclude air from the mixture of sediment and substrate solution prior to incubation was necessary, and (2) the efficacy of four inhibitors when assaying the enzyme. No significant difference between two incubation methods was found (P < 0.05), indicating that it is not necessary for estimating the potential Nar activity in the sediment to construct an initial anaerobic condition by air extractions prior to incubation. Toluene (1.0 mL/g sediment) and dry heat sterilization effectively and persistently inhibit the reduction of nitrate to nitrite during the incubation of 42 h. The authors concluded that both should be used as preferred inhibitors. In contrast, chloramphenicol (30 μg/g sediment) and moist heat sterilization inhibitors restrained nitrate reduction for <24 h only. In addition, it was found that no nitrite produced was substantially reduced in 24 h. Therefore, it should be needless for potential Nar activity estimation in the sediment to add 2,4-dinitrophenol to inhibit nitrite reductase.  相似文献   

Cloud computing and virtualization within the regional climate model and evaluation system     

Chris A. Mattmann  Duane Waliser  Jinwon Kim  Cameron Goodale  Andrew Hart  Paul Ramirez  Dan Crichton  Paul Zimdars  Maziyar Boustani  Kyo Lee  Paul Loikith  Kim Whitehall  Chris Jack  Bruce Hewitson 《Earth Science Informatics》2014,7(1):1-12

The Regional Climate Model Evaluation System (RCMES) facilitates the rapid, flexible inclusion of NASA observations into climate model evaluations. RCMES provides two fundamental components. A database (RCMED) is a scalable point-oriented cloud database used to elastically store remote sensing observations and to make them available using a space time query interface. The analysis toolkit (RCMET) is a Python-based toolkit that can be delivered as a cloud virtual machine, or as an installer package deployed using Python Buildout to users in order to allow for temporal and spatial regridding, metrics calculation (RMSE, bias, PDFs, etc.) and end-user visualization. RCMET is available to users in an “offline”, lone scientist mode based on a virtual machine dynamically constructed with model outputs and observations to evaluate; or on an institution’s computational cluster seated close to the observations and model outputs. We have leveraged RCMES within the content of the Coordinated Regional Downscaling Experiment (CORDEX) project, working with the University of Cape Town and other institutions to compare the model output to NASA remote sensing data; in addition we are also working with the North American Regional Climate Change Assessment Program (NARCCAP). In this paper we explain the contribution of cloud computing to RCMES’s specifically describing studies of various cloud databases we evaluated for RCMED, and virtualization toolkits for RCMET, and their potential strengths in delivering user-created dynamic regional climate model evaluation virtual machines for our users.  相似文献