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根据对蓖麻发育期的观测,结合当地气象条件,分析了阿克苏种植蓖麻的适应性及栽培中应采取的趋利避害的技术措施。 相似文献
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通过分析不同气候年型温度、光照、降水等气象因子对棉花发育期及产量因素的影响,得出在棉花关键发育期和产量因素形成期,温度条件对棉花产量起着决定性的作用。 相似文献
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目前惯用≥10℃积温来表示大豆播种至成熟的温度指标和热量资料状况,该方法存在不足,采用大豆生育期积温的计算方法,能更客观地反映大豆对热量的需求和当地热量条件,而且更准确地表达热量状况对大豆产量的影响。 相似文献
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根据国家规范中关于采暖气候条件的规定,计算了我国连续11年冬暖地1987-1997年1月平均温度,冬季平均温度及与1961-1990年常年值比较,并用≤5℃日数,负积温变化等采暖气候指标分析了暖冬对能源消耗的影响。 相似文献
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用积温界定章丘大葱最佳播种期 总被引:2,自引:0,他引:2
利用章丘市1990~2002年冬半年的气象资料,对章丘大葱苗抽苔开花情况进行了分析,发现冬前积温过多是葱苗抽苔开花的主要原因。在实际生产中,应用气候预测结果适时播种和早浇冬水,是防止葱苗抽苔开花培育壮苗的有效措施。 相似文献
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温度是农业环境的重要因子之一,作物为了完成其发育阶段或整个生育期要求一定的积温。目前用的有活动积温和有效积温两种,但这种积温与作物生育的关系上存在着不稳定因素,我国杂交水稻气象科研协作组织提出积温不稳定的原因是由于作物发育速度与积温之间为非线性关系,特别高温与低温都抑制作物发育,从而导致积温的不稳定。在日本学者和内岛工作的基础上沈国权提出了当量积温的概念,他认为在一定的温度条件下,发育速度正常。所需的积温为最小值,温度过高或过低均会使发育速度减慢,所需积温增加,而使用活动积温订正后所得到的当量积温,则表现出比活动积温和有效积温更好的稳定性。但是当量积温的计算和应用在我国至今尚未广泛开展,为此,本文用春小麦分期播种的资料通过一系列计算,对当量积温进行初步探讨。 相似文献
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黑龙江省热量资源及积温带的划分 总被引:4,自引:0,他引:4
在原黑龙江省农业气候区划提出的5条积温带的基础上,根据1961~1994年的资料,利用旬平均气温内插的方法求出界限温度的初、终日期及积温,并利用Barnes客观分析方法求出0.2×0.2网格点上的积温值,重新划分了黑龙江省的积温带。 相似文献
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唐秀 《沙漠与绿洲气象(新疆气象)》2015,9(4):50-54
通过对2014年阿勒泰地区沙棘萌动期—开花期—坐果期跟踪观测和历年发育期、冻害调查,发现2014年阿勒泰地区沙棘发育期较历年明显偏早10天左右,且花期遭遇轻度冻害。通过对有记录以来的气候资料分析确定阿勒泰地区大部分地方沙棘花期在4月20日以后,其中,青河在5月1日以后。本文将2014年4-5月气温与历年同期气温相比较,发现2014年4月气温存在前期高,后期低,且回升趋势和历年趋势相反的异常现象。进一步分析1954-2014年4月21日-5月15日之间的5县一市-5℃、-4℃、-3℃以下最低气温发生概率,结合2014年花期冻害程度,发现沙棘花期冻害率与最低气温和其降幅成正相关,其冻害率均在20%以下,确定阿勒泰地区沙棘花期冻害指标为-4℃。这为沙棘花期冻害预警、产量预报提供了科学依据。 相似文献
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黄淮地区一次冷锋暴雨天气过程的预报分析 总被引:1,自引:0,他引:1
利用常规天气图、地面加密资料、数值预报产品、卫星云图和多普勒天气雷达资料等,对2007年7月18-19日出现在黄淮地区的暴雨天气过程进行了综合分析.结果表明:暴雨是高空西风槽、冷锋和副热带高压边缘强盛的西南暖湿急流共同作用产生的;强降水产生在地面中尺度辐合线附近.在高层干冷、低层暖湿的大气不稳定条件下,地面冷空气的侵入触发了不稳定能量的释放,同时低层辐合、高空辐散的高低空配置,引发了强降水的产生.卫星云图和多普勒天气雷达资料在暴雨临近预报中起着重要作用. 相似文献
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基于1961—2017年京津冀地区126个气象观测站逐日最低气温和降水资料,分析该区域寒潮发生频次时空变化特征,在此基础上通过定义的干湿判别指标分析区域性寒潮的干湿特征。结果表明:(1)京津冀地区单站寒潮年平均发生频次空间分布呈西北多东南少,86%的站点寒潮年发生频次呈减少趋势。(2)1961—2017年寒潮累计发生站次呈显著减少趋势(P<0.001),气候倾向率为-5.7站次·a^(-1),且在1983年发生突变。1961—1971年寒潮累计发生站次出现峰值,从1972年开始锐减,2007—2017年寒潮平均发生站次为历史最少。(3)1961—2017年区域性寒潮发生频次年际变化总体呈递减趋势,气候倾向率为-0.282次·(10 a)^(-1),1960年代冬季区域性寒潮发生频次最多,1970年代秋季和春季最多,2000年代冬季和春季为次高峰期,2011—2017年3个季节最少。区域性寒潮发生频次季节分布中以秋季出现最多、其次是冬季、春季最少;10月、11月寒潮最为活跃。(4)京津冀地区区域性寒潮过程干过程发生频次最多,2011—2017年区域性寒潮过程干湿特征趋向于干过程和湿过程两极化分布。 相似文献
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Regional and global climate model simulated streamflows for high-latitude regions show systematic biases, particularly in the timing and magnitude of spring peak flows. Though these biases could be related to the snow water equivalent and spring temperature biases in models, a good part of these biases is due to the unaccounted effects of non-uniform infiltration capacity of the frozen ground and other related processes. In this paper, the treatment of frozen water in the Canadian Land Surface Scheme (CLASS), which is used in the Canadian regional and global climate models, is modified to include fractional permeable area, supercooled liquid water and a new formulation for hydraulic conductivity. The impact of these modifications on the regional hydrology, particularly streamflow, is assessed by comparing three simulations performed with the original and two modified versions of CLASS, driven by atmospheric forcing data from the European Centre for Medium-Range Weather Forecast (ECMWF) reanalysis (ERA-Interim) for the 1990–2001 period over a northeast Canadian domain. The two modified versions of CLASS differ in the soil hydraulic conductivity and matric potential formulations, with one version being based on formulations from a previous study and the other one is newly proposed. Results suggest statistically significant decreases in infiltration and therefore soil moisture during the snowmelt season for the simulation with the new hydraulic conductivity and matric potential formulations and fractional permeable area concept compared to the original version of CLASS, which is also reflected in the increased spring surface runoff and streamflows in this simulation with modified CLASS over most of the study domain. The simulated spring peaks and their timing in this simulation are also in better agreement to those observed. This study thus demonstrates the importance of treatment of frozen water for realistic simulation of streamflows. 相似文献
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2018年在黑龙江省庆安县选用寒地水稻龙粳31品种进行淹水试验,在拔节孕穗期、抽穗开花期,分别设定3个淹水深度(1/3株高、2/3株高、3/3株高)、2个淹水历时(3 d、7 d)共12个淹水处理,测定淹水前后的株高、叶面积、干物质及收获后的每穗粒数、结实率、千粒重及产量等。结果表明:水稻淹水后,株高、叶面积指数、干物质平均增长量基本高于同时期对照组,在一定程度上可以说明适度的淹涝胁迫对水稻植株生长具有促进作用,拔节孕穗期各项与对照组相比的增长程度均低于抽穗开花期;不同淹涝胁迫均导致水稻减产,拔节孕穗期全淹没7 d减产最严重,穗结实粒数仅55粒,千粒重16.9 g,远低于对照,减产率高达70%,抽穗开花期全淹没7 d减产也较严重,穗结实粒数为71粒,千粒重略低,但单位面积有效穗数最少,为2.83×106穗,减产率达57%;淹水深度1/3 h、2/3 h、3/3 h处理的平均减产率依次为16%、18%、48%,淹水持续3 d、7 d的平均减产率分别为21%、33%,可见随着淹水深度加深、淹水历时加长,水稻减产幅度加大;淹涝胁迫条件下,拔节孕穗期水稻产量的下降幅度大于抽穗开花期,导致两个发育期减产的主要产量构成因素分别为穗结实粒数、单位面积有效穗数。 相似文献
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Mariana Barrucand Walter Vargas María Laura Bettolli 《Meteorology and Atmospheric Physics》2014,123(3-4):143-154
This paper studies the climatic conditions of warm and cold dry months in the humid and semi-humid Argentine region and some aspects of the regional circulation related to these cases. The climatic analysis of warm (temperatures above percentile 80) and cold (temperatures below percentile 20) dry months is based on precipitation and temperature data registered at reference stations over a period of at least 70 years, while the associated circulation is derived from daily data of geopotential height at 500 hPa from NCEP-DOE Reanalysis 2 database. The reference station for the center of the country registered a greater number of warm dry months during both the warm season (October–March) and the cold season (April–September), whereas the reference stations in the north-east and center-east showed differences depending on the time of the year, with more cold dry months during the April–September season and more warm dry months in the October–March season. A classification of daily fields of geopotential height anomalies at 500 hPa was used to analyze the atmospheric circulation related to warm and cold dry months. The circulation patterns were obtained by applying principal component analysis and cluster analysis. Findings show that some mid-level circulation patterns occur with a significant different frequency during the warm dry months or the cold dry months studied. Finally, cases of spatially extended precipitation-deficit conditions (hereinafter generalized droughts) were studied, noting dominant patterns that are coherent with the previous results. 相似文献
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An observational analysis of the structures and characteristics of a windy atmospheric boundary layer during a cold air outbreak in the South China Sea region is reported in this paper. It is found that the main structures and characteristics are the same as during strong wind episodes with cold air outbreaks on land. The high frequency turbulent fluctuations(period<1 min) are nearly random and isotropic with weak coherency, but the gusty wind disturbances(1 min相似文献