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1.
本文通过对合川市1972-1996年秋蚕茧单产及总产与蚕期各时段气象因子进行的相关分析,找出与单、总产相关显著的气象因子,用逐步回归方法,将单、总产的气候波动产量与上述因子建立回归预测模式,据此可得出影响秋蚕产量的主要气象因子,同时可根据蚕期长期天气预报,预测出当年秋蚕发种量。通过讨论分析,提出合川市秋蚕出库发种时间庆从8月上旬调整为8月中旬至8月下旬前期。  相似文献   

2.
通过对合川市1972-1996年秋季蚕单产及总产与蚕期各时段气象因子进行的相关分析,找出与单、总产相关显著的气象因子,用逐步回归方法,将单、总产的气候波动产量与上述因子建立回归预测模式,据此可得出影响秋蚕产量的主要气象因子,同时可根据蚕期长期天气预报,预测出当年秋蚕发种量,通过讨论分析,提出合川市秋蚕出库发种时间应从8月上旬调整为8月中旬中期至下旬前期。  相似文献   

3.
泌阳春蚕生长的气象条件及春茧产量预报   总被引:3,自引:0,他引:3       下载免费PDF全文
秦仁和  杜瑞莉 《气象》1995,21(2):48-50
分析研究了春蚕生长的气象条件,得出了影响春蚕生长诸多气象因素中关键的因素是温度和相对湿度。并以此为线索,寻找春茧产量预报因子,运用双重检验逐步回归方法建立泌阳春蚕产茧量预报方程,其历史拟合率达91.0%。  相似文献   

4.
濮阳县天气气候条件对夏玉米产量的影响   总被引:2,自引:0,他引:2  
利用1978 ̄1997年濮阳县气象资料和夏玉米产量资料,分析了丰歉年夏玉米生育期气候条件的差异,确定了不同生育阶段的适宜气象要素指标。  相似文献   

5.
马铃薯产量与气候条件的灰色动态预测模型   总被引:4,自引:0,他引:4  
利用互助县多年马铃薯产量资料和气候条件进行统计分析,阐述了气象条件对马铃薯产量的影响,总结出影响互助马铃薯产量的主要因子是降水量,其次是地中5cm平均温度和生长期间的平均气温,影响产量的关键期为结薯期,其次是淀粉积累期,利用灰色关联动态预报方法建立模型进行马铃薯产量预测。  相似文献   

6.
气象条件对小麦产量的影响   总被引:1,自引:0,他引:1  
  相似文献   

7.
内蒙古玉米主产区气候条件对产量的影响   总被引:3,自引:0,他引:3  
选取内蒙古主要农业区赤峰、通辽、呼市、临河为代表站 ,利用数理统计方法 ,分析了上述 4个站点多年玉米产量与各生育期气象因子的相互关系 ,得出降水量、气温、风速是影响玉米产量的主导因子。而影响玉米生长的关键期是玉米的拔节期和乳熟期 ,同时利用多元回归统计方法 ,建立了玉米单产与气候因子的综合预报模型 ,并用近年的资料对模型进行回代检验 ,拟合率达 83%。  相似文献   

8.
气候条件对金丝小枣产量与品质的影响   总被引:4,自引:0,他引:4  
李连起  邢同怠  赵明云 《气象》1998,24(8):57-57
为探索气候条件对金丝小枣主要生长期的影响,以及造成产量和品质不稳定的原因,从气候角度对枣树的生长发育进行了分析研究。发现:枣树开花坐果期间的空气相对湿度是关系坐果率的主导因子;果实生长期间的连阴雨易引起病害,是影响其产量和品质的重要因素。根据研究结果,提出了提高坐果率、保证产量和品质的相应对策。  相似文献   

9.
研究泰安市郊区 1 989~ 1 998年张种产茧量与同期气象要素关系 ,结论认为春茧张产主要与 4月气温、降水存在正相关 ,与 5月下旬的气温成反相关。夏蚕张产主要与 7月气温成反相关。对有效开展蚕茧生产气象预报服务有一定指导意义。  相似文献   

10.
研究泰安市郊区1989~1998年张种产茧量与同期气象要素关系,结论认为春茧张产主要与4月气温、降水存在正相关,与5月下旬的气温成反相关。夏蚕张产主要与7月气温成反相关。对有效开展蚕茧生产气象预报服务有一定指导意义。  相似文献   

11.
Climatology of hail in France   总被引:2,自引:0,他引:2  
Within the framework of a doctoral thesis in geography, we endeavored to draw up the first map showing hail risk in France. The creation of this map is mainly based on the data of hail measuring networks. This map is corroborated, moreover, by the analysis of hail damage maps. Insurance data used to measure relative hail damage are the base premium rate levels expressed as a percentage of assets insured on a single crop, in this case grapes. These levels reflect well, over the long term, the regional hierarchy of damage, without it being necessary to correlate them directly in terms of frequency and intensity of hail. The regions that suffer the most hail stretch from the southwest to the east-central area of France, passing through the Massif Central. One must also note the southern Alps as a strongly hail-prone region. From the diagonal line of high hail risk emerge two gradients of decreasing intensity and frequency of hail. Toward the west, the risk of hail diminishes strongly, attaining a minimum level in Brittany and on the English Channel coast. Toward the southeast, hail diminishes near the Mediterranean coast. The climatological explanations of this map are so far only hypotheses. Hail is not the exclusive feature of a single climate; it seems on the contrary to be the hallmark of regions of climatic contact. The line of maximal hail risk is situated at the frontier between the oceanic and Mediterranean influences. This conflict is readily measurable in the southwest part of France where the pyrenees channel the Mediterranean influences at low levels. The map of hail risk is also the reflection of the probability of southwestern flow at high altitudes. In the east-central area of France (around Lyon), the local topography can amplify hail energy especially on leeward slopes.  相似文献   

12.
三伏由秦汉时盛行的五行学说延伸而来,主要指中原地区气候上一年中最闷热的一段时期.利用1960~2004年我国范围内432站观测的逐日最低(Tmin)、最高气温(Tmax)和湿度值构建人体舒适度指数(THI),并分三伏区、准三伏区、潜在三伏区和非三伏区辨识了我国的气候三伏特征及其在时间上的跃变,得到华北、江淮和江南3个地...  相似文献   

13.
A Fourteen-Year Climatology of the Southwest Vortex in Summer   总被引:4,自引:0,他引:4       下载免费PDF全文
Statistical studies were conducted on the southwest vortex(SWV) during the summers of 2000–13 using high-resolution reanalysis data with a horizontal resolution of 0.5°× 0.5°. A total of 578 SWVs were detected, with a maximum interannual frequency of 55. The variation of the interannual frequency featured a period of around six years. The most active period of SWVs was early July and the maximum occurrence of SWVs appeared in early morning(0200–0800 Beijing Standard Time(BST)). Most of the SWVs were short-lived, with only 66 cases(11.4%) lasting for more than 24 h. In addition, the moving tracks and three-dimensional shape of long-lived(≥ 36 h) SWVs are also presented. For those SWVs that lasted for more than 12 h, four types of SWVs(Types I–IV) were identified using a new method, and the results indicated that the dynamical and thermodynamical conditions before the formation of SWVs are effective indicators of the subsequent evolution of the vortex and associated severe weathers. Moreover, a further level of classification was also constructed for Type II SWVs, which accounted for the largest proportion out of Types I–IV, and the results indicated that the lifespan, radius and maximum 6-h precipitation were all closely related to the intensity of precipitation before the formation of SWVs.  相似文献   

14.
15.
欧亚冬季温带反气旋活动的气候特征   总被引:1,自引:0,他引:1  
田笑  智协飞 《气象学报》2016,74(6):850-859
利用NCEP/NCAR再分析数据,通过判定和追踪温带反气旋的客观方法统计分析了1948-2013年欧亚地区冬季温带反气旋的生成、消亡、移动、生命史、强度等气候特征。结果表明,反气旋的主要源地位于蒙古高原、伊朗及其周边地区、地中海沿岸、中西伯利亚、波罗的海西北部、俄罗斯东北部等地,其中,蒙古高原和伊朗等地也是强反气旋最主要的源地。反气旋活动的大值分布区和反气旋生成的大值中心分布十分相似,主要活跃区对应低空平均经向温度梯度大值区和高空脊前。除源于蒙古高原和西伯利亚东北部的强、弱反气旋的移动距离差别不明显外,其他地区的反气旋移动距离与强度有密切关系。持续1-2 d的反气旋占总数的44.2%,而只有3.2%的反气旋生命史超过一周,且强反气旋比弱反气旋更易持续较长时间。   相似文献   

16.
The annual and seasonal frequency, geographical distribution, and intensity of British hailstorms are examined. In 1986, the Tornado and Storm Research Organisation (TORRO) developed a Hailstorm Intensity Scale to characterise around 2500 hailstorms known to have occurred in Great Britain since the first documented hailstorm event of 1141 AD. The most intense British hailstorm reached intensity H8 on the TORRO international scale which extends from intensities H0 to H10. This paper focuses on over 800 hailstorms that reached TORRO intensity of H3 or more, the “severe” category. Analyses are presented for the historical period and the most recent 50-year period, 1950 to 1999. Consideration is given to examining the 50 most intense hailstorms (TORRO intensity H5–6 or more) known to have occurred in Britain since 1650. These storms all occurred between the months of May and September with a well-defined peak during July. These exceptional storms typically followed a track from the S, SSW or SW to the N, NNE or NE with a swath length of 25 km or more (reaching 335 km in one case) and a swath width sometimes in excess of 10 km.  相似文献   

17.
In addition to the occurrence of atmospheric blocking,the climatology of the characteristics of blocking events,including duration,intensity,and extension,in four seasons over the Northern Hemisphere was analyzed for the period 1950-2009.The seasonality and spatial variations of these characteristics were studied according to their longitudinal distributions.In general,there were sharp discrepancies in the blocking characteristics between winter and summer,and these differences were more prominent over the Atlantic and Pacific Oceans.The blocking not only occurred more frequently but also underwent stronger amplification in winter;likewise,the blocking occurred less frequently and underwent weaker amplification in summer.There are very strong interrelationships among different blocking characteristics,suggesting that they are supported by similar physical factors.In addition,the relationship between blocking over different regions and East Asian circulation was examined.Ural-Siberia is a major blocking formation region in all seasons that may exert a downstream impact on East Asia.The impact is generally weak in summer,which is due to its lower intensity and smaller duration.However,the extratropical circulation over East Asia in summer can be disturbed persistently by the frequent occurrence of blocking over the Asian continent or the Western Pacific.In particular,the blocking frequency over the Western Pacific significantly increased during the study period.This climatological information provides a background for studying the impact of blocking on East Asian circulation under both present and future climate conditions.  相似文献   

18.
Summary There are only six locations in Alaska for which global radiation data of more than a year in duration are available. This is an extremely sparse coverage for a state which covers 1.5×10&6 km2 and stretches over at least three climatic zones. Cloud observations are, however, available from 18 stations. We used fractional cloud cover and cloud type data to model the global radiation and thus obtain a more complete radiation coverage for Alaska. This extended data set allowed an analysis of geographic and seasonal trends. A simple 1-layer model based on Haurwitz’s semi-empirical approach, allowing for changes in cloud type and fractional coverage, was developed. The model predicts the annual global radiation fluxes to within 2–11% of the observed values. Estimated monthly mean values gave an average accuracy within about 6% of the measurements. The estimates agree well with the observations during the first four months of the year but less so for the last four. Changing surface albedo might explain this deviation. Previously, the 1993 National Solar Radiation Data Base (NSRDB) from the National Renewable Energy Laboratory (NREL) modeled global radiation data for 16 Alaskan stations. Although more complete and complex, the NREL model requires a larger number of input parameters, which are not available for Alaska. Hence, we believe that our model, which is based on cloud-radiation relationship and is specifically tuned to Alaskan conditions, produces better results for this region. Annual global solar radiation flux measurements are compared with results from global coverage models based on the International Satellite Cloud Climatology Project (ISCCP) data. Contour plots of seasonal and mean annual spatial distribution of global radiation for Alaska are presented and discussed in the context of their climatic and geographic settings. Received July 16, 1997 Revised May 18,1998  相似文献   

19.
Synoptic Climatology of Air Pollution in Moscow   总被引:8,自引:0,他引:8  
Summary Seasonal synoptic indices are developed employing principal components analysis and cluster analysis for Moscow and using surface and upper air meteorological data. Synoptic types are analysed in terms of circulation patterns and air mass characteristics. The indices are used to examine weather-induced variability in CO and NO2 concentrations for different land use types and in the context of multiple pollution sources. Anticyclonic conditions in spring, summer and autumn are identified as producing high pollution concentrations. Local depressions developing in the low pressure gradient fields in summer are another synoptic type resulting in high levels of air pollution. Extremely cold anticyclonic conditions in winter result in high CO but low NO2 levels. Weather patterns characterised by strong winds associated either with an established zonal flow or the passage of a cold front caused high NO2 concentrations in the areas affected by elevated sources. Received October 28, 1997 Revised January 26, 1998  相似文献   

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