Design of farmland gis for precision agriculture   总被引：1，自引：1，他引：0  

ANKai XIEGao-di LENGYung-fa XIAOYu 《中国地理科学(英文版)》2003,13(1):20-24

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A Coupled Calibration and Modelling Approach to the Understanding of Dry-Land Lake Oxygen Isotope Records     

Matthew D.?JonesEmail author  Melanie J.?Leng  C. Neil?Roberts  Murat?Türke?  Rana?Moyeed 《Journal of Paleolimnology》2005,34(3):391-411

Comparisons between climate proxies and instrumental records through the last two centuries are often used to understand better the controls on palaeoarchives and to find relationships that can be used to quantify changes in pre-instrumental climate. Here we compare an 80-year-long annually resolved oxygen isotope record from Nar Gölü, Turkey, a varved lake sequence, with instrumental records of temperature, precipitation, wind speed, relative humidity and calculated values of evaporation, all of which are known to be possible controls on lake oxygen isotope systems. Significant relationships are found between the isotope record and summer temperatures and evaporation suggesting these are dominant controls on the isotope hydrology of this non-outlet lake. Modelling the stable isotope hydrology of the lake system allows these relationships to be tested independently. We show that the isotope record follows the same trends in the temperature and evaporation records but that, even when combined, these two climatic factors cannot fully explain the magnitude of change observed in the isotope record. The models show the lake system is much less sensitive to changes in evaporation and temperature than the climate calibration suggests. Additional factors, including changes in the amount of precipitation, are required to amplify the isotope change. It is concluded that proxy-climate calibrations may incorrectly estimate the amplitude of past changes in individual climate parameters, unless validated independently.  相似文献   

沉淀法采集天然水中¹⁴C样品的试验研究     

叶祥清  陈铁成  冷达明  金力 《地理研究》1985,4(1):79-84

本文叙述了沉淀法采集天然水中¹⁴C样品的方法。  相似文献   

2018年中国气候主要特征及主要天气气候事件   总被引：2，自引：0，他引：2  

周星妍  曾红玲  王遵娅  孙劭  陈鲜艳  柳艳菊  邹旭恺  王凌  赵琳  侯威  王有民  朱晓金  钟海玲  郭艳君  黄大鹏  李莹  张颖娴  蔡雯悦  孙冷  章大全  顾薇  李多  崔童  石帅 《气象》2019,45(4):543-552

2018年,我国气候属于正常年景,气候灾害偏轻。全国平均气温为10.09℃,较常年偏高0.54℃,春、夏季气温创历史新高,秋、冬季气温接近常年。全国平均降水量为673.8 mm,较常年偏多7.0%。全国降水夏、秋季偏多,冬季偏少,春季接近常年同期。华南前汛期开始晚,结束早,雨量少;西南雨季开始和结束均接近常年,雨量多;入梅晚、出梅早,梅雨量少;华北雨季开始和结束均早,雨量多;华西秋雨开始和结束均晚,雨量少;东北雨季开始和结束均接近常年,雨量少。2018年,生成和登陆台风多、登陆位置偏北、灾损严重。低温冷冻害及雪灾频发,损失偏重。其他气象灾害,如暴雨洪涝、干旱、强对流、沙尘暴影响均偏轻。  相似文献   

A study on soil basic characteristics,main microbial flora and typical metal fraction surrounding coal gangue dump in Xiangtan Hunan Province,south of China     

Huan He  Fen-Fen Hong  Xiu-Xiang Tao  Guan-Hua Huang  Yun-Wei Leng  Ju-Fang Shao  Yi-dong Zhao 《Environmental Earth Sciences》2016,75(6):488

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夏季南海西部中尺度物理过程对营养盐和叶绿素a分布特征的影响   总被引：1，自引：1，他引：0  

冷晓云  杨阳  孙军  张桂成  徐文喆  冯媛媛  郭术津  陈建芳  王东晓 《海洋学报》2016,38(4):66-75

通过对2014年8月31日-9月26日国家自然科学基金委南海西部综合航次的调查结果分析,发现在中南半岛沿岸海域存在具有低温高盐的冷涡和位于其东南部海域具有高温低盐的暖涡。相对于暖涡和其他海域,冷涡水团含有更高的营养盐,并在50 m、75 m和100 m层增加明显,DIP分别高0.21 μmol/L、0.39 μmol/L和0.23 μmol/L,DIN分别高4.94 μmol/L、7.56 μmol/L和3.76 μmol/L,DSi分别高2.55 μmol/L、5.25 μmol/L和3.46 μmol/L,说明冷涡对提高初级生产力具有明显的营养优势条件和巨大潜力;叶绿素a最大值均出现在50 m层,其中以海南岛近岸海域最大,冷涡在25 m层提高初级生产力明显,主要是受营养盐影响显著;而在75 m、100 m层可能受到冷涡带来的低温环境而导致叶绿素a含量不高。  相似文献   

Synthesis,Mechanism, and Performance Assessment of Zero‐Valent Iron for Metal‐Contaminated Water Remediation: A Review     

Sana Ullah  Palwasha Faiz  Siwen Leng 《洁净——土壤、空气、水》2020,48(9)

Recently, increased industrial and agriculture activities have resulted in toxic metal ions, which has increased public concern about the quality of surface and groundwater. Various types of physical, biological, and chemical approaches have been developed to remove surface and groundwater metal ions contaminants. Among these practices, zero‐valent iron (ZVI) is the most studied reactive material for environmental clean‐up over the last two decade and so. Although ZVI can remove the contaminants even more efficiently than any other reactive materials. However, low reactivity due to its intrinsic passive layer, narrow working pH, and the loss of hydraulic conductivity due to the precipitation of metal hydroxides and metal carbonates limits its wide‐scale application. The aim of this work is to document properties, synthesis, and reaction mechanism of ZVI for the treatment of metal ions from the surface and groundwater in recent 10 years (2008–2018). So far, different modified techniques such as conjugation with support, bimetal alloying, weak magnetic field, and ZVI/oxidant coupling system have been developed to facilitate the use of ZVI in various environmental remediation scenarios. However, some challenges still remain to be addressed. Therefore, development and research in this field are needed to overcome or mitigate these limitations.  相似文献   

邢台地震区浅部构造特征及其与深部构造的耦合关系   总被引：15，自引：4，他引：11       下载免费PDF全文

赵成斌  孙振国  刘保金  顾梦林  冷欣荣  李长法  李德庆 《地震地质》1999,21(4):417-424

根据邢台7-2 级和6-8 级地震震中区的浅层和超浅层地震勘探结果,查明了震中区浅部铲形断裂的性质及活动年代,认为新河断裂(F1) 自晚更新世以来已不再活动,它不是发震断裂。另外,结合该区深地震反射剖面和深地震测深剖面结果,讨论了震中区的深浅部构造形态及它们的相互关系,从而确定了发震断裂应为震源之下的高倾角超壳断裂①。邢台地震的发生是由于地幔岩浆的上侵作用产生附加应力场,并与区域构造应力场共同作用使该断裂重新活动,引发了邢台地震,并引起浅部断层及地表物质的运动  相似文献   

处理大型数据时内存不足的解决办法     

刘洪  冷德惠 《物探化探计算技术》1999,21(2):182-185,192

本文给出了处理大型数据时内存不足的五种解决方法：即：（１）尽可能空闲基本内存;（２）利用覆盖技术;（３）利用虚拟存储技术;（４）利用一些编译程度;（５）利用ｈｕｇｅ指针。  相似文献   

西兰公路太峪黄土隧道充填注浆技术     

周烨  冷曰梅 《煤田地质与勘探》1999,27(6):67-68

黄土隧道村砌后,回填密度差、空隙多,潜在隐患大。本文以太峪黄土隧道为例,介绍了充填注浆的实践经验,质量检验表明,注浆起到了充填、加固、止水的效果。  相似文献