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1.
越冬花椰菜气候适应性研究及灾害防御技术 总被引：1，自引：0，他引：1
2002~2004年试验研究结果表明,越冬花椰菜幼苗期适宜温度为15~25℃,最低温度5~7℃,最高温度25~30℃。莲座期适宜温度为4~20℃,最低-1~-3℃,最高21~22℃。花球形成期适宜温度一般为14~21℃,最低8~10℃,最高21~30℃。花椰菜生育期耗水量在767.2~933.5 mm之间,水分利用效率最高,超过950 mm或低于510 mm水分利用效率均显著降低。花椰菜生育期间低温冷害和高温伤害是造成减产和品质降低的主要气象灾害。 相似文献
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对2001~2004年豫东地区越冬花菜发育期的光照、温度、水分等条件进行田间试验获得的数据进行统计分析,结果表明:豫东地区越冬花菜幼苗期适宜温度为15~25℃,最低温度5~7℃,最高温度25~30℃;莲座期适宜温度为4~20℃,最低温度-1~3℃,最高温度21~22℃;花球形成期适宜温度一般为14~21℃,最低温度8~10℃,最高温度21~30℃。花菜生育期耗水量在765~940 mm之间,水分利用效率最高,超过950 mm或低于510 mm时,水分利用效率显著降低。该研究为开展越冬花菜高产优质栽培技术,提高花菜越冬的抗灾能力提供了理论和实践基础。 相似文献
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影响蔬菜生长发育的环境条件包括三个方面 :一是气象条件 ,即温度、光照、水分和空气 ;二是土壤条件 ,即土壤结构、质地、无机和有机养分等 ;三是生物条件 ,即土壤微生物、病虫害、杂草等。实践证明 ,气象条件对蔬菜产量的高低、上市的早晚影响很大。1 温度条件各种蔬菜的生长发育对温度有一定的要求 ,在最低温度以下和最高温度以上停止生长。在最适温度条件下 (表 1)生长发育最快。表 1 各种蔬菜适应的温度范围蔬菜种类 适应温度范围 /℃适宜最高最低适合种植的月平均温度 /℃适宜最高最低葱蒜类 18～ 2 52 8～ 3 0 0～ 10 12～ 2 4 2 97… 相似文献
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湿度特别是相对湿度是专业气象服务必不可少的预报内容之一。不同行业对湿度的要求不尽相同,例如有利于纺织业的气象条件是：纺纱的适宜温度为21℃～26℃,相对温度为51％～70％;织布最佳温度为15℃～21℃,相对湿度为71％～88％。而温度为25℃～30℃,相对湿度在60％左右对卷烟生产过程有利。气温在15℃以下,相对湿度在70％以下粮食害虫难以生存。食品加工的最佳气温为5℃～28℃,相对湿度为45％～75％。因此,根据各行各业对相对湿度的需求,开展相对湿度的预报,可为用户合理安排生产、节约能源、提高产品质量提供依据。1武汉市相对湿… 相似文献
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小麦培育壮苗是丰产的基础,因为壮苗成穗率高.壮苗的标准一般是:主茎生长5～7片叶,叶宽色深,冬前3～4个分蘖,5～7条次生根.
冬前壮苗的形成与气象条件的关系很密切,在水分状况良好的情况下,主要是由播种时的温度和播种到入冬前的累积活动温度决定的.有关研究指出,小麦出苗的适宜温度为15～20℃,分蘖的适宜温度为6～12℃. 相似文献
7.
凤凰县位于湖南省西部边缘、武陵山西南端,本县气候条件对发展晒红烟生产十分有利。 晒红烟是一种喜光、喜温、需水量较大的经济作物,大田生育期约100天左右,其间生长下限温度为10℃,上限温度为35℃,适宜温度为18～25℃,≥10℃活动积温2359.1℃,需水600mm以上。 相似文献
8.
基于山西岢岚地区2005—2014年共1218个雨雪天气日的NCEP FNL资料(1°×1°)与探空资料,采用偏差、绝对差、相关系数和偏差区间占有率的统计方法,对常规物理量(温度、相对湿度、纬向风和经向风)和诊断物理量(T800-500、Td800和TTd700)进行统计分析。结果表明:常规物理量中的温度平均偏差值和绝对差值最小、相关系数值最大,分别为-0. 22℃、1. 02℃、0. 90,可信度最高;而相对湿度的平均偏差值和绝对差值最大、相关系数值最小,分别为12. 31%、19. 68%和0. 63,可信度最低;纬向风和经向风的可信度相差不大,略低于温度;诊断物理量T800-500、Td800和TTd700的偏差值分别为-0. 08℃、1. 50℃和2. 79℃,绝对差值分别为1. 21℃、3. 33℃和4. 14℃,相关系数值分别为0. 95、0. 92和0. 74,偏差值为[-5,5]占总数百分比分别为98. 77%、80. 30%和75. 04%。即T800-500可信度最高,TTd700指数可信度最低。 相似文献
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柑桔性喜温暖、耐阴、根部好气好水,一般栽培地要求年平均温度15℃以上,绝端最低温度不低于-10～-11℃,全年≥10℃的活动积温温州蜜柑等以5000～6000℃为适宜,周年需水量较大,非灌溉栽培区年雨量一般为1200～2000mm。衢州是浙江省主要柑桔产区之一。 相似文献
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我局从1999～2003年,测报工作连续4年未出现错情,在此期间共有1个250个班,9个百班无错通过上级业务部门验收.在仪器保管、使用、维护上符合要求,对外报送的各种表、簿都能做好出门合格. 相似文献
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Summary Considering the effects of causal mechanics on geophysical problems enables us to explain a number of phenomena, which cannot
be explained from conventional positions. This paper shows that the introduction of the force of causality in a simple barotropic
hydrodynamic model of weather forecasts results in the outcomes, which, on the one hand, can not be described from the positions
of classical hydro-thermodynamics, whilst on the other hand, exist in nature. 相似文献
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A. A. Lavrova E. S. Glebova I. V. Trosnikov V. D. Kaznacheeva 《Russian Meteorology and Hydrology》2010,35(6):363-370
Due to the complex orography and the presence of the moisture-saturated air, the Mediterranean region is characterized by
the increased baroclinic and convective instability, that leads to the sudden cyclogenesis and the formation of dangerous
weather phenomena. The results are given of the investigation of formation mechanisms of Mediterranean cyclones, peculiarities
of stages of their evolution and dynamical processes, which occur throughout the atmosphere, using the regional numerical
ETA model of the atmosphere by the example of individual cases of the cyclogenesis over the Mediterranean Sea. It is revealed
that the cold Arctic air outbreak (the intrusion of the cold Arctic air) to the south of the Western Europe, leading to the
formation of the areas of the baroclinic instability and the increased moisture content of the air in the area of the vortex
origin, favors the cyclogenesis. The use of the vertical coordinate η in the model enabled to compute more precisely the vertical
wind speed, therefore, the influence of the orography on the moisture content and precipitation increase became pronounced.
The transformation of the structure of meteorological fields in the course of the development of vortexes is considered. The
computation of the helicity is made, and it is shown that this characteristic can be one of the earliest predictors of cyclogenesis. 相似文献
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Chunguang CUI Wen ZHOU Hao YANG Xiaokang WANG Yi DENG Xiaofang WANG Guirong XU Jingyu WANG 《大气科学进展》2023,40(4):711-724
Here, we analyze the characteristics and the formation mechanisms of low-level jets(LLJs) in the middle reaches of the Yangtze River during the 2010 mei-yu season using Wuhan station radiosonde data and the fifth generation of the European Centre for Medium-Range Weather Forecasts(ERA5) reanalysis dataset. Our results show that the vertical structure of LLJs is characterized by a predominance of boundary layer jets(BLJs) concentrated at heights of 900–1200 m.The BLJs occur most frequently at 230... 相似文献
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流场配置及地形对西南低涡形成的动力作用 总被引：10，自引：8，他引：10
本文采用定常二层模式讨论较小地形及高、低层流场配置对西南低涡形成的动力作用。指出了西南低涡的形成是与盆地、河谷以及其上气流分层有关的一种定常态.在上、下为西风分层时期,低层的浅薄暖湿西风有利于西南低涡的形成.在上、下为东、西风分层时期,上层浅薄东风亦有利于西南低涡的形成.小型的凸起山脉对西南低涡的形成没有作用. 相似文献
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On the determination of the height of the Ekman boundary layer 总被引：1，自引：1，他引：1
S. S. Zilitinkevich 《Boundary-Layer Meteorology》1972,3(2):141-145
The heighth
of the Ekman turbulent boundary layer determined by the momentum flux profile is estimated with the aid of considerations of similarity and an analysis of the dynamic equations. Asymptotic formulae have been obtained showing that, with increasing instability,h
increases as ¦¦1/2 (where is the non-dimensional stratification parameter); with increasing stability, on the other hand,h decreases as –1/2. For comparison, a simple estimate of the boundary-layer heighth
u
determined by the velocity profile is given. As is shown, in unstable stratification,h
u
behaves asymptotically as ¦¦–1, i.e., in a manner entirely different from that ofh
. 相似文献
17.
1引言我国执行接地降阻剂测试的技术标准是全国电力系统起草的:“接地降阻剂暂行技术条件修改稿”。在技术要求中要求接地降阻剂的酸碱值应在7￣12范围内。在实际使用中发现该技术要求对接地降阻剂的酸碱值要求范围并不合理,需要分析和讨论。2接地降阻剂的PH值接地降阻剂的酸碱性对地网的使用寿命至关重要,为了不让接地降阻剂腐蚀接地体或者减弱接地降阻剂对接地体的腐蚀,在接地降阻剂测试的技术要求中,对接地降阻剂的酸碱度有一定的限制。国内各厂家用于生产接地降阻剂的偏弱酸的盐类进行了对镀锌钢材腐蚀的试验,结果是这些镀锌钢材均受到… 相似文献
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文章选用阴山山脉山北乌拉特后旗、白云、达茂旗、苏尼特左旗、化德,山南杭后旗、包头、呼和浩特、察右前旗、兴和1971—2000年气温、降水量、天气现象等资料进行对比分析,得到阴山山脉对内蒙古自治区中部地区气象要素影响初步结论。 相似文献
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Summary ?Some features of the climate system that can be considered predictors of the onset and end of the convective season over
the Amazon were identified using one-month lag correlations and field composites. The fields analyzed were sea surface temperature
(SST), outgoing long-wave radiation (OLR), vertical velocity and upper tropospheric winds.
Warm (cold) anomalies in the SST in the tropical North Atlantic and the Caribbean Sea tend to be associated with delayed (early)
onsets. Likewise, there is a tendency towards a delayed (early) end of the convective season with cold (warm) anomalies in
these ocean regions. In addition, the SST in the cold tongue region of the equatorial Pacific is negatively, though weakly
correlated with the onset date. The signal of this SST is more evident in the case of the end date, which is earlier with
respect to its mean date in most of El Ni?o cases.
The convective activity intensity itself conditions the onset and the end of the convective season, as it is evidenced by
the behavior of the OLR and the vertical velocity fields. The more (less) intense the convective activity over South America
during the preceding month, the earlier the onset and the later the end of the convective season on the Amazon region.
The prediction of the onset and end dates of the convective season in the Amazon region was explored using a simple multiple
regression technique based on the variables that have shown precursor signals with respect to these dates. The correlation
coefficient between the predicted and the observed onset date is 0.81, and in the case of the end date, it is 0.76. The skill
to predict early, delayed and normal categories was high, since in more than two thirds of the cases the category was successfully
predicted, and there were no predictions of categories opposed to those observed.
Received July 23, 2001; revised February 22, 2002; accepted April 26, 2002 相似文献