南宁市蔗糖行业人工增雨服务效益调查评估

分析了南宁市种植甘蔗的气候适应性,以及降雨量与甘蔗生长、蔗茎产量及含糖量的关系,并对比分析了为南宁糖业股份有限公司所属蔗区实施人工增雨前后的甘蔗产量及蔗糖分,认为蔗糖分前后变化不大,但实施人工增雨后甘蔗产量有较显著提高,从而能获得令人满意的经济效益;在此基础上提出了做好人工增雨工作的改进思路。     

云南甘蔗种植气候类型和特点

为了掌握云南甘蔗主产区气候差异,在依据甘蔗生物学特性选定评价指标的基础上,采用系统聚类法进行了云南甘蔗主产区气候类型分类。划分的6类甘蔗气候类型具有较好的区域性分布,各类型间气候特征差异明显,主要体现在4—10月平均日照时数、5—10月平均降水量、11月至次年2月平均日照时数、9—12月累计温差等指标上。结合甘蔗历史单产数据,分析了影响各类型单产的主要气象指标。研究表明影响云南甘蔗单产的主要因子为生长季的温度和光照,正常年份下降雨量为非限制因子。此外采用9—12月的平均最低和最高气温作为含糖量影响因子而入选分类指标,使分类结果更具实用性。     

光、温对大豆生长发育的影响

光照时数对大豆出苗到开花期日数有明显影响,前人已多次证明。我们的试验亦得出同样结论:光照时数与该发育期日数之相关系数为+0.87(P<0.01)。这里我们侧重讨论光照时数对大豆开花到成熟期的影响。 一、光照对开花到成熟期日数的影响     

气象现代化助力幸福和美中山

中山市处于北回归线以南,热带北缘,光照充足,热量丰富,气候温暖。太阳辐射角度大,终年气温较高。全年太阳总辐射量最强为7月,最弱为2月。光照时数较为充足,有高产的光能利用潜力。气候温暖,四季宜种。年际问平均温度变化不大。     

可照时数的微机计算程序

可照时数的含义是太阳中心自出地平线至入地平线,其直射光线在无地障及云雾烟尘遮掩情况下,照耀地面之时间。把一年或一月的实际日照时数与可照时数相比称日照比数或日照百分率。这对于研究云量分布和日照时间与农作物的生长关系,以及太阳能的利用都有一定的意义。 由天文学可知,某地的可照时数与该地的纬度及赤纬有关,其公式为:     

开封市花生产量与气象因素的关联度分析

运用灰色关联度分析理论,对开封市2001-2010年花生产量和气象因素的关联度进行分析.研究结果显示开封市花生产量与各气象因素之间的关联度按照由大到小依次排列为:8月份平均气温＞7月份平均气温＞6月份平均气温＞6月份光照＞5月份平均气温＞8月份光照＞6月份降水＞5月份降水＞7月份降水＞5月份光照＞8月份降水＞7月份光照.开封花生产量与气温条件的关联度最大,特别是在花生播种期间,平均气温仍然不稳定,容易受冷空气的影响,不利于花生的出苗和生长,因此选择适宜的播种期,对提高产量十分重要.花生进入荚果发育期,要特别注意防范暴雨洪涝和连阴雨天气对花生产量造成的不利影响.花生播种需要适宜的土壤水分含量,如果降水量不足,要及时造墒,降水量过多、墒情过湿要晾墒.花生开花期如果降水量不足,土壤干旱会使开花数量减少甚至开花中断.荚果成熟期如果降水量不足,会严重影响花生荚果的充实和含油量的提高.因此在花生开花期和荚果发育后期如果降水量偏少,应及时采取人工灌溉,增加土壤含水量,以提高花生产量.     

甘蔗开榨防冻保鲜的气象指标

玉山糖厂甘蔗制糖生产的经济效益不高,最主要原因就是冬季气温低,榨蔗受冻害严重,影响了出糖率。我们应用糖厂近十年的甘蔗含糖量、出糖率的纪录,对照同期相应的气温资料,初步找到了甘蔗受冻害的规律,并制定了气象服务指标,在生产实践中产生了良好的效益。1 气温对甘蔗糖分的影响甘蔗投榨的大部分时间都在寒冬季节,而该时期是一年当中气温最低,雨、雪、冰冻最多的时期,低温冻害在绝大多数年份是不可避免的。玉山糖厂在以往的榨季中,从未采取过任何防冻保鲜措施,事实证明,甘蔗糖分变化与气温变化的关系十分密切（见表1）。     

甘蔗糖份累积的动态模拟及其在开榨期预报中的应用

甘蔗蔗糖份含量的高低,主要取决于农业和气象两大因素,其影响不仅限于蔗糖份的前期含量,而且影响榨季的平均蔗糖含量。从甘蔗蔗糖份累积的生态过程来看:其蔗糖份累积的进程及累积的速度,在很大程度上左右于蔗糖份累积前期及过程中的气象条件。本文拟从气象角度模拟出蔗糖份累积的动态变化模式,揭示甘蔗蔗糖份累积的动态规律,并试图利用该模式进行甘蔗适宜开榨期预报。     

河西酿酒葡萄生育模型及气象条件分析

分析了河西走廊酿酒葡萄果径生长和含糖量累积规律。结果发现：果粒生长动态呈抛物线型，有两个明显的生长高峰期。生长关键期出现在7月上旬～8月上旬，生长率占总生长率的64％～78％；含糖量累积遵循“S”型生长函数。糖份积累关键期出现在8月中旬中期至下旬，这一时期含糖量累积最快，日累积糖量在0．48％～0．84％，净累积量占累积总量的73％～77％；影响糖份累积的关键气象因子主要是光温积和气温日较差。日照时间长，气温高，温差大，糖份积累快，含糖量高。建立了葡萄糖份累积气候模型，以此为依据，计算了河西不同气候区含糖量地理分布，为葡萄基地建设和选择不同葡萄品种提供了依据。     

一九八一年三、四月份天气

多雨的暖舂“春雨绵绵”是江南春天的气候特点,而今年的春天,雨水比往年更多(比去年略少),三、四月份总雨量浙北300毫米左右,比常年偏多50—100毫米,西南山区500—650毫米,比常年偏多120—260毫米,其它地区400毫米左右,比常年偏多60—120毫米。光照时数偏少,也是今年春天明显的一个特点,三、四月份浙北只有200小时左右,比     

Characteristics of rainfall systems accompanied with Changma front at Chujado in Korea

The rainy season from June to July in the East Asia is called the Changma in Korea, the Meiyu in China, or the Baiu in Japan. The mesoscale convective systems which occur near a front frequently lead to severe weather phenomenon such as localized gust and heavy rainfall. An intensive field experiment was conducted at Chujado (33.95°N, 126.28°E) to find out the characteristics of the precipitating system using information such as the raindrop size distribution, kinematic features during a Changma period between June 21 2007 and July 11 2007. Different characteristics of three identified rainfall cases in a Changma frontal precipitation system occurred from 5 to 6 July in 2007 at Chujado area have been identified. Based on the radar reflectivity and raingage at Chujado, each rainfall system maintained for 7 hours, 4 hours, and 9 hours, respectively. According to the analysis of a total vertical wind shear (TVWS) and a directional vertical wind shear (DVWS), the temperature gradient was the strongest near the surface and both warm and cold advections were occurred in all cases but at different levels. The deep warm advection was related to the longer rainfall lifetime and stronger rainrate, but smaller raindrop size. The unstable atmospheric condition, which has cold advection at the surface and warm advection in higher level, caused the larger size diameter of raindrop. The echo top height of 30 dBZ was around 6 km in the two rainfall systems and around 4 km in the other one. The number concentrations of raindrop has turning point at the drop size of 2 mm in diameter. The stronger (weaker) updraft and downdraft were also related to the decreased number concentration of smaller (larger) size drops and increased that of the larger (smaller) drops.     

Two Types of Diurnal Variations in Heavy Rainfall during July over Korea※

This study examined the characteristics of the diurnal variations of heavy rainfall (≥110 mm in 12 hours) in Korea and the related atmospheric circulation for July from 1980?2020. During the analysis period, two dominant pattens of diurnal variation of the heavy rainfall emerged: all-day heavy rainfall (AD) and morning only heavy rainfall (MO) types. For the AD-type, the heavy rainfall is caused by abundant moisture content in conjunction with active convection in the morning (0000?1200, LST; LST = UTC + 9) and the afternoon hours (1200?2400 LST). These systems are related to the enhanced moisture inflow and upward motion induced by the strengthening of the western North Pacific subtropical high and upper-tropospheric jet. For the MO-type, heavy rainfall occurs mostly in the morning hours; the associated atmospheric patterns are similar to the climatology. We find that the atmospheric pattern related to severe heavy rainfalls in 2020 corresponds to a typical AD-type and resembles the 1991 heavy-rainfall system in its overall synoptic/mesoscale circulations. The present results imply that extremely heavy rainfall episodes in Korea during the 2020 summer may occur again in the future associated with the recurring atmospheric phenomenon related to the heavy rainfall.     

The significant increase of summer rainfall occurring in Korea from 1998

Using the techniques of empirical orthogonal function analysis and the change-point analysis to total summer rainfall from 60 weather observation stations, it was found that total summer (from June to September) rainfall in Korea has increased greatly since 1998. The increase level was higher in the season between Changma and late summer rainy season (from the end of July to early August) and in the season after late summer rainy season (after the early September). Among the reasons for increase of summer rainfall in Korea since 1998, the north-high and south-low pressure pattern formed around Korea drew attention. As northeasterlies and southeasterlies derived from these two pressure systems converged in Korea, rainfall and moisture convergence increased most in Korea of the East Asia regions (0–60°, 100–180° E). In addition, the atmosphere above Korea revealed that there were strong ascents from the ground to 200-hPa level with the warm air to 500-hPa level.     

Numerical simulation of a heavy rainfall event in China during July 1998

Summary A detailed analysis associated with this case has been carried out (Zhao et al., 2001). In order to conduct further research on the meso-β scale system, which is the directly influencing system, the heavy rainfall that occurred in Wuhan (Station no.: 57494) and Huangshi (Station no.: 58407), Hubei Province during July 1998 are simulated using higher resolution and more complete initial data, after the large scale fields and rainfall areas have been simulated successfully. The simulation results indicate that there are meso-β scale weather systems which developed and dissipated near Wuhan and Huangshi during 1800 UTC 20 July to 0600 UTC 21 July and 1800 UTC 21 July to 0600 UTC 22 July in 1998, respectively. The life cycle of the meso-scale system is about 12 hours and its horizontal scale is from 100 to 200 km. These are characteristic of a typical meso-β scale system. By analyzing the vertical section of wind field and other physical variables during the mentioned-above two periods, it is found that horizontal convergence, ascending motion and positive vorticity of the middle and lower troposphere are strengthened during the heavy rainfall periods near the above mentioned two places. In addition, the wind disturbance in middle and lower troposphere may be a possible triggering mechanism for the occurrence of the meso-β weather system. A budget analysis of the meso-scale system indicates that the sources of moisture and positive vorticity are different during the different stages of the meso-scale systems. Finally, a three dimensional conceptual model of the meso-β scale systems causing the sudden heavy rainfall in Wuhan and Huangshi is suggested. Received November 4, 2001 Revised December 28, 2001     

West African monsoon: is the August break “breaking” in the eastern humid zone of Southern Nigeria?

In July, heating of the continents in the Northern Hemisphere results in strengthened monsoon systems which bring rains to West Africa. In Nigeria, the annual rainfall total decreases from over 3,800 mm at Forcados on the coast to under 650 mm at Maiduguri in the north-east of the country. June, July, August and September are the rainiest months throughout the country. In many parts of the south, however, there is “supposed to be” a slight break in the rains for some 2 to 3 weeks in late July and early August or the so called “August break”. In this study, we are underscoring the obvious that climate is changing. The daily series of rainfall data for 1983–2003 analyzed between the months of July–August for some sites in the Eastern humid zone of Southern Nigeria shows that the “August break” may indeed “be breaking”. We have discussed some practical approaches to climate change research in this monsoon region.     

赤道平流层QBO与我国7月雨型的关联

根据1953～1991年赤道平流层纬向风资料分析,得出我国东部地区7月份主要雨带位置与赤道平流层30～50 hPa平均纬向风准两年振荡（以下简称赤道平流层QBO）有较好的关联。在西风位相条件下,我国7月主要雨带位置较偏北;在东风位相条件下,我国7月主要雨带位置易偏南。它们之间的关系主要是通过对对流层环流的影响相联系的。利用赤道平流层纬向风的变化规律并结合冬季北太平洋对流层环流特征,对我国7月主要雨带类型的预报,有一定实用意义。     

The Upstream “Strong Signals” of the Water Vapor Transport over the Tibetan Plateau during a Heavy Rainfall Event in the Yangtze River Basin

A heavy rainfall event that occurred over the middle and lower reaches of the Yangtze River Basin(YRB) during July11–13 2000 is explored in this study. The potential/stream function is used to analyze the upstream "strong signals" of the water vapor transport in the Tibetan Plateau(TP). The studied time period covers from 2000 LST 5 July to 2000 LST 15 July(temporal resolution: 6 hours). By analyzing the three-dimensional structure of the water vapor flux, vorticity and divergence prior to and during the heavy rainfall event, the upstream "strong signals" related to this heavy rainfall event are revealed. A strong correlation exists between the heavy rainfall event in the YRB and the convective clouds over the TP. The "convergence zone" of the water vapor transport is also identified, based on correlation analysis of the water vapor flux two days and one day prior to, and on the day of, the heavy rainfall. And this "convergence zone" coincides with the migration of the maximum rainfall over the YRB. This specific coupled structure actually plays a key role in generating heavy rainfall over the YRB. The eastward movement of the coupled system with a divergence/convergence center of the potential function at the upper/lower level resembles the spatiotemporal evolution of the heavy rainfall event over the YRB. These upstream "strong signals" are clearly traced in this study through analyzing the three-dimensional structure of the potential/stream function of upstream water vapor transport.     

青藏高原汛期降水异常空间分布及水汽配置

青藏高原汛期(5—9月)降水具有南北反相的空间分布特征,利用青藏高原67个台站1967—2008年逐月降水资料,分别讨论了汛期各月降水的主要空间分布型以及初夏(5—6月)和盛夏(7—8月)对应的水汽配置和环流异常.结果表明:初夏高原降水以南北反相型(North-South Reverse Type,NSRT)为主,全区一致型(Whole Region Consistent Type,WRCT)次之;盛夏高原降水以WRCT为主.高原降水呈现NSRT分布时,初夏水汽由高原南部输向北部,而盛夏高原北部为水汽辐合区,南部为水汽辐散区.高原降水呈现WRCT分布时,初夏高原水汽主要来自西太平洋,盛夏水汽主要来自阿拉伯海向东转向的水汽输送,该水汽输送由高原西南地区进入高原.在500 hPa位势高度场上,初夏(盛夏)降水两种主要空间分布型的位势高度差异以经(纬)向差异为主,且影响高原降水异常分布的系统多为深厚系统.     

Regional variability of convection over northern India during the pre-monsoon season

In general, the overall differences in activity and timing of convection are a result of the influence of large-scale regional and synoptic flow patterns on the local mesoscale environment. The linkage between the space?Ctime variability of observed clouds and rainfall, with large-scale circulation patterns and mesoscale variables over north India during the pre-monsoon season (March to May) is the focus of this paper. We use harmonic analysis to identify the first hour of rainfall for 42 stations spread over the north Indian region during the pre-monsoon summer season (March to May), from 1980 to 2000. The variability is observed to be systematic, with large regions having similar timing for occurrence of rainfall. The stations located in the foothills of the Himalayas have a late night to early morning maximum of first hour rainfall. In the northwestern plains, the first hour of rainfall mostly starts in the early afternoon to evening hours. Further eastward, the rainfall occurs in the late evening hours. Overall, there is a gradient in the occurrence of first rainfall events from late afternoon hours in the southern sections of the north Indian region to nocturnal maxima in the higher altitude regions. Five of these stations, located in different regions of homogenous timing of rainfall occurrence, were selected to analyze in detail the variable trigger for convection. Our results indicate that convective episodes occur mostly in association with the passage of westerly troughs over this region. These upper atmosphere troughs enable moisture to flow from the surrounding oceanic regions to the dry inland regions and also provide some dynamic support to the episodes of convection. However, the actual occurrence of convection is triggered by local factors, giving rise to the mesoscale structure of the weather systems during this season. Specifically, over the plains of northwest India, convection is triggered in a moistened environment by diurnal solar heating. The late night to early morning convection over the foothills is triggered by the orography, when the moistened airflow is normally incident on the mountain slopes. Further eastward, the primary trigger for localized moist convection is downdrafts from south-eastward propagating convective systems that originate at a north?Csouth dry line over north India. These systems propagate with a speed of about 15?m?s^?1. The above results are supported by geostationary satellite brightness temperature data for March to May 2008.