黑龙江省汛期逐时降水的时空变化特征分析

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

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^(-1)9:00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^(-1)8:00.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.

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- ~ 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.