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11.
湖北省2008年初低温雨雪冰冻过程气候特征分析   总被引:3,自引:0,他引:3  
2008年初,湖北省出现了严重的低温雨雪冰冻灾害,直接经济损失高达110亿元以上,有必要对灾害期间的气候特征进行系统、科学的分析和总结。对湖北省76个气象站2008年1月12日~2月3日气温、降水(雪)、日照以及低温持续日数等要素进行时空间差异分析及历史与同期比较,并选取10个代表站历史上所有低温雨雪天气过程,对其过程持续低温日数、最长连续雨雪日数、过程极端低温进行比较分析。结果表明:(1)此次过程的平均气温异常偏低,该省大部为-1~-2℃,比常年同期偏低4~6℃,为各站历史同期最低,其中主要是最高气温异常偏低所致,但极端低温并不低;(2)降雪过程频繁,雨雪量异常偏多;(3)低温冰冻持续时间长,该省大部在16~22 d,位于历史第一;(4)日照异常偏少。持续而稳定的大气环流异常形势是湖北省大范围低温雨雪天气的直接原因。  相似文献   
12.
A statistical analysis of interannual variation in a set of vegetative and generative characters over 13 years has been performed to characterize the growth and seed production dynamics of the Siberian stone pine (Pinus sibirica Du Tour) in the southeast of the forest zone in western Siberia. The results have shown that the range of fluctuations in most of vegetative characters is ordinary and their distribution is close to normal. The range of fluctuations in many generative characters is enormous (from 0 to +∞), and the distribution of their values is usually skewed, with low values being recorded several times more frequently than high values. Most variable are the proportion of abortive cones and other characters that are determined mainly in the spring of the pollination year. These characters account for a very high level of variation in the total seed production.  相似文献   
13.
本文从柑桔冻害和热害的危害因子和指标等级划分的研究和选取入手,着重探讨了长江三峡地区(湖北境内)两害显著的时空变化特征、差异与关联性及对柑桔生产的影响;揭示了80年代以来冬暖春热的重大气候变化是使两害向“两极分化”的根本原因;讨论了三峡水利工程对两害时空格局的可能调整及减灾原理;最后提出了可能的对策。  相似文献   
14.
岷江上游崩塌滑坡分布规律研究   总被引:1,自引:0,他引:1  
岷江为长江—级支流,上游长330km,自1986年以来,发生崩塌滑坡200余处,体积约2.1亿m ̄3。作者研究了岷江上游崩塌滑坡的分布规律。采用统计指标法,将岷江上游分为三种不同的崩塌滑坡分布密度区:①UXS.高密度区;②MXS,中密度区;③LXS_3低密度区。  相似文献   
15.
Data on the existence of a specific system regulating the growth, size, and structure of enterobacterial populations are first summarized in terms of the chemical ecology concept formulated by S.S. Shvarts. The role of this system in transgene functioning is described using the example of the lux operon integrated into Escherichia coli. A relatively simple test for estimating such interactions is proposed.Translated from Ekologiya, No. 2, 2005, pp. 91–96.Original Russian Text Copyright © 2005 by Pshenichnov, Maslennikova, Nikitina.  相似文献   
16.
Aspects of the trophic attributes of the mudskipper,Periophthalmus barbarus occurring in the mangrove swamps of ImoRiver estuary, Nigeria, were investigated during a 12-month period(April, 1992-March, 1993). Feeding intensity increased with size;it was higher in the dry season (November-April) than in the wetseason (May-October); monthly changes in the indices of feedingintensity were significantly correlated. Major food objectscomprised detritus and benthic algae; crustaceans, insects,macrophyte matter and sand grains were minor food objects whilefish, molluscs, Chilopoda, nematodes and fungi were unconsciouslydevoured objects. Diet varied seasonally; algae and sesarmid crabswere generally more in the dry season than during the rains whereasFPOM and fish increased in the wet over dry season. The mudskipperdisplay a high degree of euryphagy and can be considered as ageneralist and an omnivore. The lower trophic status of P. barbarusqualifies it as a good aquaculture candidate. Food richness washigher in big-sized class (BSC) than small-sized class (SSC).Size-based and seasonal variations were not apparent in foodrichness. Diet breadth was higher in the BSC than the SSC; therewas dry season increase in diet breadth.  相似文献   
17.
分析江汉平原粮食生产的优势与问题,运用商品经济的观念,提出改革开放新形势下加快江汉平原粮食开发的设想,即依托市场,按照价值规律,科学地调整种植业比例和粮食种类结构,发展优质品种,扩大优化模式及采用高新技术等,通过优质、高产、高效,促进江汉平原粮食生产的发展。  相似文献   
18.
19.
Effluent from dyeing and finishing processes is an important source of water pollution. The effectiveness of bentonite, kaolinite and sediment from a local deposit in removing methylene blue as a cationic dye from aqueous solutions has been investigated. The adsorption equilibrium (isotherm) has been determined according to Freundlich and Langmuir equations. The optimum amount is 0.5 g for all adsorbents, and the optimum pH ranges are 2-8 for bentonite and 2-6 for kaolinite and sediment. With respect to kinetic modelling, the adsorption of methylene blue on various adsorbents was fitted to a second-order equation. Also, the thermodynamic parameters were determined. The negative free energy values indicate the feasibility of the process and spontaneous nature of adsorption. The positive ΔH° values indicate the endothermic nature of the process. Thus, Egyptian clay minerals and sediments have a great tendency to remove the dye from solutions.  相似文献   
20.
The typical parameters of acid precipitation are evaluated in the forest of Vallombrosa (Tuscan Appennines) during the dry period 1988-89. Individual rain events (dry and wet deposition) were sampled in a clearing of the forest and below the canopy of an evergreen tree as well as a deciduous broadleaf tree.

In atmospheric precipitation the pH values usually vary around 4.4, with neutralization in the hot season due to calcareous material from distant sources. Relatively large concentrations of Pb and Cd are found in rain, but only in a small amount in canopy leachate. Aluminium, manganese and iron are more significantly washed off than Pb and Cd.  相似文献   
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