“地气图”方法用于省级旱涝预测的实践     

郭维栋  赵红岩  李栋梁  郭英香 《干旱气象》1998,(4)

简要介绍用“地气图”方法进行降水预测的基本思路,总结此方法的预报实践,指出省级尺度旱涝预测需要解决的几个关键问题,强调除加密观测外,上游地热涡增强的能量频散作用是下游地热涡发展的重要原因  相似文献   

南宁市引种金花茶的气候分析与评价     

廖雪萍 《气象研究与应用》1998,19(3):35-36

依据原种金花茶的生态特性及引种试验结果,通过分析南宁市的气候条件得出,南宁市适宜种植金花茶的结论  相似文献   

Deep-sea hydrocarbon seep gastropod Bathynerita naticoidea responds to cues from the habitat-providing mussel Bathymodiolus childressi     

Sharmishtha Dattagupta  Jonathan Martin  Shu-min Liao  Robert S. Carney  & Charles R. Fisher 《Marine Ecology》2007,28(1):193-198

Bathynerita naticoidea (Gastropoda: Neritidae) is a numerically dominant heterotrophic gastropod found at hydrocarbon seep sites on the upper Louisiana slope of the Gulf of Mexico. Snails of this species are commonly associated with beds of the methanotrophic mussel Bathymodiolus childressi (Bivalvia: Mytilidae), and their population structure mirrors that of the mussels they are found among. Previous studies have shown that these snails feed on bacteria and decomposing periostracum on the B. childressi shell. We predicted that B. naticoidea might be attracted to cues specific to its preferred habitat, such as dissolved methane, mucus from conspecific snails, or metabolites produced by B. childressi mussels. To examine this, we used a flow‐through Y‐maze system to investigate the behavior of B. naticoidea exposed to these potential cues. We found that the nerite is not attracted to methane, but is strongly attracted to seawater conditioned with B. childressi. The attractant appears to be specific to this type of mussel, and is not a soluble cue produced by conspecific snails.  相似文献   

Pollen assemblages and their environmental implications in the Qaidam Basin,NW China     

Shengrui Zhang  Qinghai Xu  Anne Birgitte Nielsen  Hui Chen  Yuecong Li  Manyue Li  Lingyun Hun  Jianyong Li 《Boreas: An International Journal of Quaternary Research》2012,41(4):602-613

The Qaidam Basin is one of the most sensitive areas to climate change in China, owing to its unique geographical position and ecological condition. In this study, 32 surface‐soil pollen samples were collected to reveal the relationship between modern pollen assemblages, vegetation and precipitation in the eastern region of the Qaidam Basin. The results show that Chenopodiaceae (3.8–87%, average 48%), Artemisia (1.7–64.2%, average 17.5%) and Ephedra (0–90%, average 16.3%) are the dominant pollen types in all samples, and that different pollen assemblages correspond to different vegetation types. DCA and CCA of major pollen types demonstrate that precipitation is an important factor in the control of the distribution of vegetation in the study area. The content and concentration of the three major pollen types (Artemisia, Chenopodiaceae and Ephedra) change with the mean annual precipitation, and the optimum mean annual precipitation for Ephedra, Chenopodiaceae and Artemisia is <80, 80–200 and >160 mm, respectively. Correlation analysis between the variation in grain size of the three major pollen types and the main environmental variables shows that the grain size of the three pollen types is positively correlated with precipitation in the Qaidam Basin. The results confirm that precipitation is the most important environmental factor in the Qaidam Basin, and that it has an important effect on pollen grain size in the study area.  相似文献   

数字抽取滤波器的DSP优化设计     

谭耀银  廖成旺  邓涛  赵凤花  丁炜  陈卫明 《大地测量与地球动力学》2007,27(Z1):87-90

为了降低地震数据采集系统的成本和功耗，采用数字信号处理器（DSP）实现∑-△模数转换器中的数字抽取滤波器算法。通过采取查表法、倒序循环遍历法以及模拟循环寻址法等优化方法，以较低工作频率实现了四通道四级抽取滤波运算，达到了系统设计的要求。  相似文献   

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廖成旺  邓涛  丁炜  王浩  谭耀银  陈卫民 《大地测量与地球动力学》2007,27(6):61-64

???????????????????????????????????????????????????????????????????????ж?λ?????????????????????????????????Σ??????λ?????????????????????????????????????????????μ???????????????б???????????????????????????????ú???????????????????????????????????????Ч?????б??????????????????ò??ù??????о????λ???λ?????  相似文献   

基于氮稳定同位素的九龙江口鱼类营养级研究   总被引：1，自引：1，他引：0  

廖建基  郑新庆  杜建国  陈彬 《海洋学报》2015,37(2):93-103

采用氮稳定同位素技术对2013年6—8月九龙江口采集到的隶属于13目42科61属共71种鱼类的营养级进行研究。结果表明,九龙江口鱼类的δ15 N值跨度较大,介于7.23‰~14.66‰之间。以菲律宾蛤仔(Ruditapes philippinarum)为基准生物估算出鱼类的营养级介于1.70~3.89之间,营养级最低与最高的鱼类分别为少牙斑鲆(Pseudorhombus oligodon)与多鳞鱚(Sillago sihama)。与Fishbase同种鱼类的营养级数据进行比较,83.1%的鱼类的营养级均值处于Fishbase同种鱼类的营养级范围内,但81.7%的鱼类的营养级均值比Fishbase同种鱼类的营养级均值略低;与传统的胃含物分析结果比较,58.3%的鱼类的营养级在0.5个营养级的误差范围内。基于氮稳定同位素估算的鱼类营养级较低的原因可能与本研究样品中低龄鱼及幼鱼比例较大有关。与其他方法相比,稳定同位素法在研究体型较小的幼鱼和低龄鱼营养级更具优势。鱼类营养级随其个体大小的变化明显,但存在种的差异性:不同体长的髭缟鰕虎鱼(Tridentiger barbatus)和绿鳍鱼(Chelidonichthys kumu)的营养级跨度较大,分别为1.54和1.43;而鳓(Ilisha elongata)等的营养级则跨度较小,这可能与不同鱼类的食性变化有关。  相似文献   

多角辐散地极技术在高电阻率地区的应用     

廖必军 《气象科技》2007,35(4):567-570

在高电阻率地区,建造符合要求且经济实用的地网一直是防雷工程施工的难点。因为组成地网的接地极的形状关系到材料利用效率和施工难易程度。提出了"多角辐散地极"的概念,设计制作了多角辐散地极,并选择了3个不同的地域环境,对这一设计技术进行了试验。通过与普通地网的比较,证明了在高阻率地区多角辐散地极组成的地网优于普通地网。通过对不同安装距离,不同降阻剂投放量的比较,确定了多角辐散地极的最佳安装方法,并根据试验测量的数据计算出并联系数,得出工程量的估算方法。  相似文献   

地形对降水的影响研究概述   总被引：28，自引：5，他引：23  

廖菲  洪延超  郑国光 《气象科技》2007,35(3):309-316

简要回顾了近些年来有关地形对降水影响的研究进展。介绍了地形的动力效应和热力效应,详细分析了地形的动力、热力效应引起的降水和云物理变化。重点分析了地形对气候尺度、天气尺度、中尺度及对流性天气系统降水的影响。简单地讨论了在研究地形对降水影响时观测分析、气候统计、理论分析及数值模拟方面存在的问题及其未来发展前景。  相似文献   

殷墟文化发生的环境背景及人类活动的影响   总被引：6，自引：1，他引：5       下载免费PDF全文

许清海  曹现勇  王学丽  李月丛  荆志淳  唐际根 《第四纪研究》2010,30(2):273-286

不同农业单元122个表土样品花粉分析结果表明,安阳地区表土花粉组合中草本植物花粉含量最高,以禾本科、蒿属、藜科和十字花科为主,乔木植物花粉百分含量较低,以松属、桦属、胡桃属、黄栌属、栎属为主,应为西部太行山区传播而来。汪家店和茶店陂两个全新世地层自然剖面孢粉分析表明,约 10000cal.aB.P.以前,安阳地区分布着以松属、栎属、桦属等为主的落叶阔叶林;  约 10000～8200cal.aB.P.,气候变暖,降水量增加,森林植被中夹杂着常绿栎等亚热带树种;  约 8200～3400cal.aB.P.,安阳地区进入全新世大暖期,森林植被演变为亚热带落叶阔叶和常绿阔叶混交林;  商王朝在安阳地区建都后（3400cal.aB.P.后）,乔木植物花粉急剧减少,草本植物花粉和中华卷柏百分含量升高,表明森林被大量砍伐,砍伐后的林地开垦为农田,主要种植禾本科等农作物;  两条剖面上部的冲积层中出现大量中华卷柏孢子,表明森林植被破坏后水土流失加剧。古地貌面孢粉分析也证明殷商时期安阳地区生长有亚热带落叶阔叶和常绿阔叶混交林,气候和植被条件适于野象生存;  殷墟附近为禾本科农作物花粉高含量区,表明殷商时期农业已具一定规模。  相似文献