黑龙江省主汛期降水气候特征及预测检验评估

Climate characteristic and prediction evaluation of precipitation in main flood season in Heilongjiang province

采用1961—2016年黑龙江省62个气象代表站逐日降水数据和NCEP逐日再分析资料,分析黑龙江省主汛期"七下八上"降水气候特征及其环流特征,并利用DERF2.0模式不同起报时次的结果对黑龙江省主汛期降水和环流进行了检验评估。结果表明:主汛期的降水量占夏季降水量的25%—35%,是黑龙江省夏季降水的主要时段;多雨年500 h Pa高度场出现以东北西部地区为中心的东西向的"+-+"波列,850 h Pa风场有明显的气旋存在;DERF2.0超前10 d和超前5 d对主汛期降水预测的多年平均PS评分为60分左右,超前1 d预测的PS评分为70分;DERF2.0对500 h Pa环流显著区域超前1 d的ACC多年平均为0.58,对黑龙江省南北两个区域850 h Pa纬向风显著区域超前1 d的ACC多年平均分布分别为0.48和0.52。DERF2.0对黑龙江省主汛期降水预测和环流预测均有一定的可预报性,且随着起报时间的临近,模式的预测技巧有较明显的提升。

Base on daily precipitation observational data at 62 meteorological stations in Heilongjiang province during1961-2016 and the National Centers for Environmental Prediction/National Center for Atmospheric Research（ NCEP/NCAR） reanalysis data, the characteristics of precipitation climate and atmospheric circulation from late July to early August in main flood seasons were analyzed. Precipitation and circulation in Heilongjiang province during main flood seasons were evaluated using the simulated results with different starting time from the Dynamic Extended Range Forecast Operational System 2. 0（ DERF2. 0） model. The results show that the precipitation during the main flood season accounts for 25%-35% of the cumulative precipitation in summer,which is the major period of summer precipitation in Heilongjiang province. In the years with large precipitation,a wave train with the ＂ ＋-＋ ＂ pattern in the east-west direction exists at 500 hPa and its center is located at the western region of the Northeast China. Meanwhile,cyclones are observed in the wind field at 850 hPa. The annual mean PS score for the precipitation in the main flood season is about 60 when the starting time of the DERF2. 0 simulation is 10 d and5 d ahead,and the score reaches 70 for 1 d ahead. When the starting time of the DERF2. 0 simulation is 1 d ahead,the annual mean anomaly correlation coefficient（ ACC） for circulation salient region at 500 hPa is 0. 58,and that for zonal wind at 850 hPa in the southern region and in the northern region of Heilongjiang province are 0. 48 and0. 52, respectively. The DERF2. 0 model can predict precipitation and circulation during the main flood season in Heilongjiang province to some extent,and the prediction skills improves significantly as approaching the starting time.