Abstract: A new concept,the concentrate index of precipitation which is defined as a ratio of the average rainfall per day within the period of the daily temperature≥10℃ to the average precipitation per day in a year,has been put forward to express the seasonal distribution of precipitation.This method of studying Precipitation regime will be usefull in the researches of agroclimatology and physical geography.As an example,the author has calculated and mapped the concentrate index of precipitation over the central and eastern temperate area of the United States as well as the Northern and Northeastern China.

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