黑龙江省汛期逐时降水的时空变化特征分析

利用黑龙江省1961-2014年逐时降水资料，采用线性倾向估计方法分析了汛期（5-9月）降水量、降水频率、降水强度以及不同持续时间降水的时空变化特征.结果表明：汛期逐时累积降水量平均为430.0 mm，高值区集中在松嫩平原东部和南部以及小兴安岭南部；降水频率平均为297.2 h，仅在省西部的齐齐哈尔、大庆和绥化等地以及哈尔滨西部地区偏少，其余地区台站均在300 h以上；降水强度平均在1.2~1.7 mm·h^-1之间，增加趋势显著（P<0.01），空间分布与降水频率分布相反；全省多数台站的汛期降水量、降水频率趋势变化不明显，但却有39%的台站降水强度增加明显.汛期降水量的日变化呈单峰型，超过半数的降水集中在11：00-22：00；降水频率的日变化表现出双峰型，00：00-04：00和13：00-19：00为高值区间；降水强度的日变化也呈单峰型，高值区间集中在13：00-18：00.全省的降水事件中短历时降水优势明显，降水量占总降水量的46.7%，降水历时占全部降水历时的49%；持续5~6 h的降水雨强最强，其次是持续3~4 h降水雨强，最弱的是持续1~2 h的降水雨强.

Temporal and spatial variations of hourly precipitation in Heilongjiang Province in the flood season

Based on hourly precipitation data from 1961 through 2014 in Heilongjiang Province, variations of precipitation, precipitation frequency and precipitation intensity in flood season (May-September) are analyzed. It is found that the precipitation in the flood season was 430.0 mm, the precipitation frequency was 297.2 hours, the precipitation intensity was 1.2-1.7 mm·h^-1 and the precipitation intensity had increased obviously. The precipitation change trend and precipitation frequency in most stations were not obvious, but 39% of stations had changed obviously in precipitation intensity. The diurnal variation of precipitation showed a single peak, more than half of the precipitation had concentrated in 11:00-22:00; diurnal variation of precipitation frequency was bimodal, in 00:00-04:00 and 13:00-19:00; the diurnal variation of precipitation intensity also showed a single peak, with high value interval concentrated in 13:00 to 18:00. In the province, short duration precipitation had advantage obviously, accounted for 46.7% of the total, with rainfall duration accounting for 49% of all rainfall duration; continuous 5-6 hours precipitation intensity was the strongest one, followed by continuous 3-4 hours one, and the continuous 1-2 hours one was the weakest.