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81.
In order to extend the Tallinn temperature series backward in time, three different climate proxies were used. These were: the first day of ice break-up in Tallinn port, a proxy for the mean winter air temperature (December to March); the first day of ice break-up on the rivers in northern Estonia, a proxy for the beginning of spring; and, the first day of the rye harvest, a proxy for the mean air temperature in spring and summer (April to July). On the basis of these proxies the mean winter temperature could be extended back to the year AD 1500, and the spring and summer temperature back to 1731. The series of winter temperatures was analysed for long-term trends and variations on different timescales. The most striking feature is the warming of the winters from about the mid nineteenth century to the present. The warming is especially noticeable over the latest decades. The climate from the start of the series (AD 1500) to the mid nineteenth century was in general somewhat colder, and should be recognised as a part of the Little Ice Age, though the period was intercepted by warmer winters in the first half of the eighteenth century. 相似文献
82.
83.
浑江市幅区域化探异常遥感评价筛选研究 总被引:1,自引:0,他引:1
本文介绍了根据国家计委和地矿部的要求,应用遥感地质方法,即主要通过航卫片解译,结合本区已有地质矿产分布和物化探资料的综合分析,对吉林省浑江市幅区域化探异常进行遥感评价、筛选研究的概况。文中主要阐述了区内金、多金属矿成矿地质特征,论述了断裂构造和环状构造与金、多金属矿及化探异常的关系,简介了区域化探异常遥感评价筛选和野外验证结果以及圈定的若干找矿靶区的情况。 相似文献
84.
85.
Unicellular gametophytes ofUndaria pinnatifida (Harv.) Sur. were isolated in Qingdao, P. R. China in April 1993 and in Tokushima, southern Japan in March 1995. Different
intraspecific crossings by using unicellular male and female gametophytes were successfully undertaken in Sept. of 1995 in
Qingdao. Sporophytes were transplanted to two different locations for open sea cultivation. One was at Zhanqiao (ZQ) Bay where
the water current was slower than that of another location—Taipingjiao(TPJ). A total of 218 adult sporophytes were harvested
on January 12 and 18 from TPJ and ZQ respectively. For eacn combination, 10 sporophytes were cultivated. Analysis of the morphological
characteristics of adult sporophytes indicated that the longest length between two bases of the serration of pinnate blades
(W2) is a morphological characteristic that can be transferred from the parent plant to the next generations regardless of
environmental variations. There was evidence that W2 was apparently determined by sex-linked factors, i.e., by male parental
gametophyte. Sporophytes from certain crossing combinations showed more vigorous growth than those from other crossing combinations.
It is therefore possible to select gametophyte strains which can be used as parental gametophytes for the seedling production
of sporophytes with more vigorous growth within shorter cultivation period. The morphology of hybrids from a Qingdao strain
and a Tokushima cultivated strain resembled that of both parental plants in frond features (wrinkled or smooth) and W2. Sporophyll
formation also varied with strains. The fact that adult sporophytes resulting from the same crossing combinations have identical
morphological characteristics under the same environmental conditions indicates the possibility of a new way to select strains
which are expected to be ideal for commerical production by purposely selecting, propagating, and seeding unicellular gametophytes
for sporeling production through freeliving techniques of gametophytes.
Project 39400102 supported by NSFC, also supported by National Climbing Plan B (PD-B642); and Bioengineering Center, SSTC. 相似文献
86.
东湾背斜位于准噶尔盆地南缘,采用多种地球物理及地质方法,通过多次论证,证明构造是落实的,且其烃源岩、储集层以及盖层条件都较好,但2003年完钻的东湾1井钻探结果却无任何油气显示。在深入了解准噶尔盆地南缘区域构造背景的基础上,探讨了东湾背斜的构造特征、构造演化过程及油气成藏条件,总结出东湾背斜的油气聚集规律,指出在东湾地区可能存在的两种油气藏模式,最后提出下步有利勘探目标区。 相似文献
87.
88.
在信息定义和结构化选取的基础上,根据图斑的空间分布与距离联系,给出图斑数据地理要素层结构的定义和建立过程,从而实现图斑数据制图概括中对象选取的模型化。 相似文献
89.
基于偏最小二乘回归技术时纹理特征进行线性组合,得到新的纹理特征来进行分类。实验表明,组合后的纹理特征不但提高了纹理分类的性能,而且具有一定的数据自适应能力。 相似文献
90.
高山雷达站选址对估测降水的影响分析 总被引:1,自引:0,他引:1
高山雷达站天线高度对雷达的垂直探测范围影响较大,加之中小尺度灾害性天气演生、发展的关键区域在高度1500~4500 m左右,所以高山雷达站在选址时应考虑当地零度层平均高度和雷达的垂直探测范围。通过定量估测层状云降水的个例实践,发现探测高度会限制定量估测降水,探测高度对近距离降水估测影响较小,但对远距离降水估测影响较大,原因主要是雷达的垂直探测范围及当地零度层亮带高度的影响。故在高山雷达站选址中应考虑雷达的垂直探测范围及当地零度层亮带高度的影响,同时对已建设完成的高山天气雷达应考虑对高山雷达做0°仰角的观测可行性研究。 相似文献