11-印度马哈拉施特拉邦暖云年改造试验
11-Year Warm Cloud Modification Experiment in Maharashtra State, India
摘要：
在1973-74，1976，1979-86年第11-夏季风（6 - 9月）季节，在印度浦那地区4800平方公里的区域内进行了一次暖云改造试验。试验采用双区域交叉设计，区域随机化，并使用仪器飞机进行催化和云物理测量。在飞机进入云底以上200-300米高度的云层时，细粉状盐（氯化钠）颗粒被释放到季风云（积云和层积云）中。发现暖云对盐粉播撒的响应与云的物理特性密切相关，垂向厚度和液态水含量。垂直厚度大于1公里、LWC大于0.5克/立方米的云，在撒上盐粒（模态直径10微米，浓度为每升云空气1）时，降雨量增加24%，在4%的水平上有显著意义。浅云（垂直厚度小于1公里，LWC小于0.5克/立方米）时，播种表现出消散的趋势。在未播云（对照）和播云（目标）中进行的云物理观测为检验暖云修正假说的适用性提供了一些有用的证据。云模式的计算结果表明，云底的适度辐合对云的生长和降水的发展是必不可少的。在有利的动力条件下（云-基准面的辐合），对暖云进行吸湿粒子播种，可能会加速碰撞-合并过程，从而增强降雨。
英文摘要：
A warm cloud modification experiment was carried out in an area of 4800 Sq.Km in the Pune region,India, during the 11-summer monsoon (June-September) seasons (1973-74, 1976, 1979-86). A double-area cross-over design with area randomization was adopted and an instrumented aircraft was used for seeding and cloud physical measurements. Finely pulverised salt (sodium chloride) particles were released into the monsoon clouds (cumulus and stratocumulus) during aircraft penetrations into the clouds at a height of 200-300 m above the cloud-base. The warm cloud responses to salt seeding are found to be critically dependent on the cloud physical characteristics e.g., vertical thickness and liquid water content. Clouds with vertical thickness greater than 1 km, LWC greater than 0.5 gm/cubic m when seeded with salt particles (modal diameter 10 micro m, concentration 1 per litre of cloud air) produced increase in rainfall of 24 per cent significant at 4 per cent level. Shallow clouds (vertical thickness less than 1 km, LWC less than 0.5 gm/cubic m) when seeded showed tendency for dissipation. The cloud physical observations made in not-seeded (control) and seeded (target) clouds have provided some useful evidence to test the applicability of the warm cloud modification hypothesis. The results of the cloud model computations suggested that moderate convergence at the cloud-base is essential for the cloud growth and development of precipitation in the real world. Hygroscopic particle seeding of warm clouds under favourable dynamical conditions (convergence at the cloud-base level) may result in the acceleration of the collision-coalescence process resulting in the enhancement of rainfall.
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