中国春季干旱指数大多存在5 ~ 8年的短周期年际周期变化，12 ~ 13年、15 ~ 16年的长周年际周期变化存在于部分区域，个别区域还存在20年长周期年际周期变化。

It is proved that the drought index exists 5 ~ 8 a period in the most areas, it exists 12-13 a and 15-16 a period in some areas, it also exists 20 a period in specific area.

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一次指数平滑模型充分体现了负荷连续变化的趋势性和周期性，但是没有详细考虑天气因素对负荷的影响。

Single exponent smoothness model fully embodies the characters of trend and cycle of the continuous varying power load, but it can not think about the effect of the weather elements carefully.

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显示经济指标变化与经济活动总周期变化同步变化的指数。

An index of economic indicators whose movements closely coincide with the overall cycle of economic activity.

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