CERES—玉米模拟模式的数值试验及应用

利用美国的ＣＥＲＥＳ玉米模拟模式对河南省伊川县１９９２、１９９３年共６期玉米分期种资料进行了模拟，对生育期和籽粒产量的模拟效果较好。     

利用单多普勒雷达资料做冷流暴雪的中尺度分析

基于单多普勒天气雷达资料采用EVAP方法反演风场, 并结合径向速度、 反射率因子、 自动气象站和探空风场等观测资料, 对2005年12月6～7日山东半岛一次冷流暴雪过程的中尺度特征进行了深入分析, 结果表明： (1)雷达回波呈狭窄带状, 移动缓慢近乎停滞, 径向速度上存在风向切变线, 烟台和威海的暴雪不同步是冷流暴雪的典型特征; (2)首次通过雷达反演证实了逆风区实际就是风场切变在径向速度图上的反映, 垂直各层水平风场存在中尺度切变线, 且与强回波带相对应, 切变线的位置决定暴雪的落区; (3)通过雷达反演风场和风廓线共同揭示出强降雪产生时对流层中层有西北风、 西南风和东北风三股气流, 明显的西南气流位于850～700 hPa, 表明冷流降雪过程并非传统认为的仅有西北冷平流, 而是不同气流辐合的结果; (4)对流层中层的西南暖平流为云的播种和反馈机制提供了有利的天气背景条件, 使得冷流降雪增强, 这在常规观测资料中无法看到。     

柳州市糯玉米高产稳产的气象条件分析

通过分期播种试验得出糯玉米的单产、发育期天数、双苞率、穗行数、行粒数、秃顶度等产量因子。以确定高产量的形成与这些产量因子之间的关系:穗行数、行粒数的数值越大,产量就越高。秃顶度则相反,产量高秃顶度小,产量低秃顶度大;高积温易形成高产量,降水条件要求充足且分布均匀也有利于高产量的形成,在南方地区略少的日照有利于干物质的积累。同时分析了气象要素对穗长、穗行数、行粒数的影响:降水有利于高穗位的形成,日照则相反,秃顶度与雨日呈负相关,与日照呈正相关,穗行数与积温呈负相关。行粒数与积温呈正相关,与日照呈负相关。     

积层混合云结构特征及降水机理的个例模拟研究

积层混合云是我国一种重要的降水系统, 其降水既有对流云又有层状云特征。基于积层混合云的重要性, 本文利用中尺度数值模式WRF(Weather Research and Forecasting Model), 结合三维粒子运行增长模式对2012年5月29日北京地区的一次积层混合云降过程进行了模拟研究。模拟的降水与雷达回波与实测结果基本一致。在此基础上, 重点分析了混合云系中积状云与层状云各自的微物理结构特征与降水的发生机理等。结果表明:降水过程云内存在着明显的“播种—供给”机制, 层状云中“播种—供给”机制相对简单。而对流云区中由于降水粒子可以发生上下多次的循环增长, “播种—供给”机制可在云的上下层间双向进行, 云中粒子群可以增长得更大。在积层混合云中, 在低层, 层状云中已有的水凝物粒子进入内嵌的积云块中, 而在高层水成物粒子又从积云中落到层云中, 积层混合云系充分发挥了积云和层云各自的优势, 从而降水效率较高。     

Microphysical Effects of Cloud Seeding in Supercooled Stratiform Clouds Observed from NOAA Satellite

Based on the satellite retrieval methodology, the spectral characteristics and cloud microphysical properties were analyzed that included brightness temperatures of Channels 4 and 5, and their brightness temperature difference (BTD), the particle effective radius of seeded cloud track caused by an operational cloud seeding and the microphysical effects of cloud seeding were revealed by the comparisons of their differences inside and outside the seeded track. The cloud track was actually a cloud channel reaching 1.5-km deep and 14-km wide lasting for more than 80 min. The effective radius of ambient clouds was 10-15μm, while that within the cloud track ranged from 15 to 26μm. The ambient clouds were composed of supercooled droplets, and the composition of the cloud within the seeding track was ice. With respect to the rather stable reflectance of two ambient sides around the track, the visible spectral reflectance in the cloud track varied at least 10%, and reached a maximum of 35%, the reflectance of 3.7μm in the seeded track relatively decreased at least 10%. As cloud seeding advanced, the width and depth were gradually increased. Simultaneously the cloud top temperature within the track became progressively warmer with respect to the ambient clouds, and the maximum temperature differences reached 4.2 and 3.9℃at the first seeding position for Channels 4 and 5. In addition, the BTD in the track also increased steadily to a maximum of 1.4℃, compared with 0.2-0.4℃of the ambient clouds. The evidence that the seeded cloud became thinner comes from the visible image showing a channel, the warming of the cloud tops, and the increase of BTD in the seeded track. The seeded cloud became thinner mainly because the cloud top descended and it lost water to precipitation throughout its depth. For this cloud seeding case, the glaciation became apparent at cloud tops about 22 min after seeding. The formation of a cloud track in the supercooled stratiform clouds was mainly because that the seeded cloud volume glaciated into ice hydrometeors that precipitated and so lowered cloud top height. A thin line of new water clouds formed in the middle of the seeded track between 38 and 63 min after seeding, probably as a result of rising motion induced by the released latent heat of freezing. These clouds disappeared in the earlier segments of the seeded track, which suggested that the maturation of the seeding track was associated with its narrowing and eventual dissipation due to expansion of the tops of the ambient clouds from the sides inward.     

石河子棉区不同热量条件对棉花纤维品质影响研究

为定量评估不同热量条件对石河子棉区棉纤维品质的影响,以当地主栽品种为材料, 2003至2007年在莫索湾气象站和乌兰乌苏农业气象试验站内进行分期播种试验,并收集同期气象观测资料,分析不同播期内开花- -裂铃期间的日最高、日最低温度、日平均温度和≥10℃、15℃、20℃活动积温等热量条件与棉花主要纤维品质特征的相关性。结果表明：①该棉区棉花纤维断裂比强度与热量条件相关最为明显,②限制该地区棉花纤维品质档次提高的主要纤维品质指标是断裂比强度,③当地主栽品种断裂比强度都具有随播期延后而减小的趋势,不同品种的比强度随播期延后反应表现不一致。     

运用经验正交函数分解建模制作麦播期降水定量预报

针对鹤壁市麦播期（９月２１日￣１０月３１日）降水量的高频振荡性，利用均值生成函数的延柘函数构成的序列，提取时间函数，作为主分量分析方法的时间函数场，制作鹤壁市麦播期降水定量预报方程并进行试报。     

滑县晚播小麦播期播量实验结果分析

滑县有１００万亩晚播小麦。为确保夏秋粮同时高产，我们开展了晚播小麦播期和播量实验。结果表明，春性品种性和半春性品种适宜播期为１０月５－２５日，最迟不晚于１０月３０日；夏秋粮双高产的适宜播期在１０月２０－２５日。播量随不同播期变化；１０月５日播种以６ｋｇ为宜，每推迟５天播种量增加１ｋｇ．     

晋中地区玉米适时早播气象条件分析

玉米生产在晋中地区具有战略性重要地位，但十年九旱的气候特征，使玉米生产几乎年年面临一个难过“三关”的问题，即春旱难过播种捉全苗关、抽雄叶丝期难过“卡脖子”伏旱关、灌浆期难过初霜冻危害关。本文通过对玉米生产中气象条件的分析，提出以适时旱播促使玉米生育期提前来避过“三关”夺取高产，这一科技措施已被晋中各地采用并证明为玉米生产过“三关”的最有效途径。     

稻茬冬小麦不同播种方式和播种量试验研究

稻茬冬小麦不同播种方式和播种量试验于2008—2009年度在江苏省农业科技综合展示基地(宿迁点)进行,试验共设计4种播种方式和3个播种量水平,研究分析不同播种方式和播种量及气象条件对稻茬冬小麦生长发育、抗逆性和产量的影响。结果表明:播种方式和播种量对冬小麦的生长发育及产量有显著影响,在生产实际中应结合具体情况采取适当的播种方式,播种量水平以每亩20万株左右基本苗较理想。在粳稻收获较晚,冬小麦无法适期播种时,可以采取稻田套播方式,播种量要适当增加;籼稻腾茬早的,可以选择收获后7 d左右人工撒播或条播;在茬口和气候等条件适宜的情况下,尽可能采取水稻收获后2 d左右进行冬小麦播种。条播能更充分的利用光温水等气候资源。