Precipitation type estimation and validation in China   总被引：7，自引：1，他引：6  

Ren-sheng Chen  Jun-feng Liu  Yao-xuan Song 《山地科学学报》2014,11(4):917-925

The results from three methods aimed at improving precipitation type(e.g., rain, sleet, and snow) estimation are presented and compared in this paper. The methods include the threshold air temperature(AT), threshold wet bulb temperature(WBT) and Koistinen and Saltikoff(KSS) methods.Dot graphs are plotted to acquire the threshold air temperature or the threshold wet bulb temperature using daily averaged air temperature, wet bulb temperature and precipitation data at 643 stations from 1961 to 1979(precipitation types are not labeled in the database from 1980 to present) in China. The results indicate that the threshold AT or WBT methods are not able to differentiate rain, sleet and snow in the most regions in China; sleet is difficult to differentiate from other precipitation types based on the two threshold methods. Therefore, one threshold AT and WBT method was used in this study to differentiate rain and snow. Based on GaussianKriging interpolation of threshold air temperature(T0and wet bulb temperature(Tw), the T0 and Tw contour lines and contour surfaces are calculated for China.Finally, a comparison between the KSS, AT and WBT methods are provided in which the KSS method is calculated based on air temperature and relative humidity. The results suggest that the KSS method is more appropriate for water phase estimation than are the other methods; the maximum precision for rain and snow is 99% and 94%, respectively. The AT method performs better than the WBT method when the critical air temperature is 2°C.  相似文献   

一种可用于藏北高寒条件的土壤空气采集器     

李卫朋  程根伟  孙建  沙玉坤  陈有超 《山地学报》2014,(4)

一般的土壤空气采集装置在藏北除不同程度存在着结构复杂、不便携带、土壤固液态杂质干扰等问题外,适用性和经济性也受到了极大的限制。基于"原位防扰动、隔离降误差、手动便携更实用"的思想,介绍了一种呈管状多层次嵌套结构且具有防水透气采气窗的便携式土壤空气原位采集器,该装置能抽掉残留空气又能防止土壤水分入渗及土壤固体组分的干扰,且工艺简单、便携易用、经济耐用,适用于藏北高寒草原的复杂自然环境。  相似文献   

中国治霾将影响澳大利亚煤铁出口     

《西部资源》2014,(1)

<正>据澳大利亚商业观察者网3月13日报道,火电厂、钢铁厂和水泥厂的煤消耗一直是中国华北地区的最大空气污染源,紧跟其后的还有工业粉尘。报道认为,北京的环保努力将使中国钢铁产量的进一步增长受限,并可能导致诸多低效的中小型冶炼炉和钢铁厂被迫关停。此次打击钢铁生产的行动与之前行动的不同之处在于,地方政府现在需对其环境质量负责。报道分析,所有这些行动可能会对澳大利亚铁矿石业产生两个大的影响。第一,中国未来将不会增加铁矿石进口。中国去年的  相似文献   

闽江河口湿地与垦殖地的空气负离子含量研究     

任洪昌  张礼宏  王纯  王维奇  闵庆文  汪旭明  曾冬萍  郑江闽 《湿地科学》2014,(4)

为了揭示垦殖对湿地空气负离子含量及空气质量的影响,分别在闽江河口天然湿地和湿地垦殖地中各设置5个采样点,进行空气负离子含量测定与分析;通过计算空气离子评价系数,对空气质量进行评价。研究结果表明,天然湿地空气负离子含量为267~837个/cm3,垦殖地为321~515个/cm3;天然湿地空气负离子含量显著高于垦殖地;总体上,在地表以上50~150 cm高度内,天然湿地空气负离子含量随高度在增加。  相似文献   

Thermodynamic properties of snow cover on sea ice during the austral summer in Prydz Bay,East Antarctica     

HAN Hongwei  CHENG Peng  LI Zhijun  LEI Ruibo  LU Peng 《极地研究(英文版)》2014,(1):10-16

The thermodynamic properties of snow cover on sea ice play a key role in the ice-ocean-atmosphere system and have been a focus of recent scientific research. In this study, we investigated the thermodynamic properties of snow cover on sea ice in the Nella Fjord, Prydz Bay, East Antarctica(69°20′S, 76°07′E), near the Chinese Antarctic Zhongshan Station. Our observations were carried out during the 29th Chinese National Antarctic Research Expedition. We found that the vertical temperature profile of snow cover changed considerably in response to changes in air temperature and solar radiation during the summer. Associated with the changes in the temperature profile were fluctuations in the temperature gradient within the upper 10 cm of the snow cover. Results of previous research have shown that the thermal conductivity of snow is strongly correlated with snow density. To calculate the thermal conductivity in this study, we measured densities in three snow pits. The calculated thermal conductivity ranged from 0.258–0.569 W?m-1?K-1. We present these datasets to show how involved parameters changed, and to contribute to a better understanding of melting processes in the snow cover on sea ice.  相似文献   

Numerical simulation and experimental research on hydrodynamic performance of propeller with varying shaft depths   总被引：2，自引：0，他引：2  

郭春雨  赵大刚  孙瑜 《中国海洋工程》2014,28(2):271-282

In order to study hydrodynamic performance of a propeller in the free surface, the numerical simulation and open-water experiments are carried out with varying shaft depths of propeller. The influences of shaft depths of a propeller on thrust and torque coefficient in calm water are mainly studied. Meanwhile, this paper also studies the propeller air-ingestion under special working conditions by experiment and theoretical calculation method, and compares the calculation results and experimental results. The results prove that the theoretical calculation model used in this paper can imitate the propeller air-ingestion successfully. The successful phenomenon simulation provides an essential theoretical basis to understand the physical essence of the propeller air-ingestion.  相似文献   

高寒草甸湍流特征量的季节变化特征   总被引：1，自引：0，他引：1  

陈云刚  张宇  王少影  尚伦宇  熊建胜  沈晓燕 《高原气象》2014,(3)

利用青藏高原东北边缘的若尔盖高寒湿地生态系统研究站玛曲高寒草甸观测场提供的2010年近地面层梯度和涡动观测资料,基于Monin-Obukhov相似理论(MOST)分析了该地区风速分量、温度、水汽和CO2的归一化标准差随稳定度参数z/L在均匀平坦地表的变化关系及其季节变化特征。结果表明,风速分量σu/u*、σv/u*和σw/u*与稳定度参数z/L呈1/3次方关系,并随|z/L|增大而增大,在近中性(|z/L|0.05)时趋于常数,且σu/u*σv/u*σw/u*;水平方向风速的归一化标准差随空气动力学粗糙度z0m的增大而减小,σw/u*无明显季节变化,可近似为常数;温度、水汽和CO2的归一化标准差在不稳定条件下与z/L呈-1/3次方关系,归一化值随|z/L|的减小而增大,在中性条件下σq/q*σc/C*σT/T*。σT/T*、σq/q*和σc/C*的季节变化分别与感热、潜热和CO2通量的季节变化相反,且主要决定于特征尺度T*、q*和C*。其中感热通量的季节变化与潜热通量、CO2通量相反,且年变化幅度最小,相应地,σT/T*的季节变化与σc/C*和σq/q*相反,且年变化幅度最小。  相似文献   

栾川钼矿采空区钻探技术试验研究   总被引：2，自引：0，他引：2       下载免费PDF全文

郑英飞  王茂森 《探矿工程》2014,41(2):22-25

针对栾川钼矿地质结构复杂、地下采空区交错纵横,采空区底板凹凸不平开孔困难,普通钻进容易造成钻孔偏斜的情况,为解决矿区面临的勘探技术难题,研究试验了以潜孔锤反循环钻探技术为核心,集成多种先进的钻探机具,采取人工造孔法、下套管导向法或实时控制参数法等钻探工艺,顺利在采空区底板打孔并钻穿多层采空区,取得了良好效果。  相似文献   

空气反循环连续取样施工中卡钻事故的预防与处理          下载免费PDF全文

李雪峰  白玉鹏 《探矿工程》2014,41(8):40-45

利用空气反循环连续取样钻进技术,在露天矿山进行生产勘探施工,对所遇到的卡钻问题进行原因分析,确定了相应的操作规程,以便预防卡钻事故的发生,并通过施工辅助孔和套铣技术,在处理卡钻事故方面取得了很好的效果。  相似文献   

多工艺空气钻进技术在深水井施工中的应用实践          下载免费PDF全文

郝文奎  宋宏兵  康亢  王树钢  郑肖亮 《探矿工程》2014,41(12):11-14

气动潜孔锤和气举反循环钻进工艺组合应用具有钻进效率高、成井质量好的特点,在水文水井及地热深井施工中应用广泛。通过在深井施工中的应用实践,阐述了多工艺空气钻进技术应用所取得的经济效益和社会效益,并摸索总结出了使用注意事项,具有很好的参考价值。  相似文献