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大兴安岭地处高纬度地区,农业生产对无霜期的依赖性很大,初霜早晚直接影响农业生产,对初霜的分析与预测具有非常重要的意义。本文利用1997-2021年大兴安岭地区7个国家站资料,采用气候统计方法,分析初霜日时空分布、变化特征;用天气学原理方法对2021年高、低空实况图、EC细网格预报图的分析,总结气象要素阈值,预测初霜;用Mann-Kendall方法对大兴安岭地区初霜日进行检验。结果表明:2021年大兴安岭地区平均初霜日在9月18日,比历年平均初霜日偏晚7 d,其中漠河站偏晚14 d,北极村站只偏晚1 d。大兴安岭北部地区比南部地区初霜日偏早,非沿江地区比沿江地区初霜日偏早;14时气温和露点温度、EC细网格地表温度、2 m露点温度、24 h变温、零度层高度预报图,对预报未来24 h、48 h初霜冻有很好的指示意义;大兴安岭地区1997-2020年初霜日突变时间在2012年,初霜日突变后较突变前平均推迟了5 d。 相似文献
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Extremely cold weather has an important influence on winter production and life in the Greater Khingan Mountains region. This paper uses the daily minimum temperature data of ground observation stations during extreme cold weather from 1974 to 2021 in the Greater Khingan Mountains region, monthly circulation index data, the spatial distribution and temporal variation characteristics of extreme cold days and extreme minimum temperature were analyzed by climate statistical method; The abrupt changes and periods of extreme cold days and extreme minimum temperature were tested by Mann-Kendall method and Morlet wavelet analysis; calculating the recurrence period of extreme minimum temperature by empirical frequency method; correlation method was used to analyze the circulation factors which had significant influence on the number of extremely cold days. The results are followed: (1) The spatial distribution of extreme cold days in the Greater Khingan Mountains region was not uniform, and gradually decreasing from northwest to south. The extreme cold days was at most 717 d in Huzhong, and at least 29 d in Gagadaki, the extreme cold days in the whole region mutated in 1979, and the average annual extreme cold days decreased 14.2 d after the mutation compared with that before the mutation, and the annual extremely cold days have a significant cycle of 2 to 4 years. (2) The extreme minimum temperature in the whole region mutated in 1990, before the mutation the extreme minimum temperature was low and after the mutation began to rise, the significant cycle of annual extreme minimum temperature was 4 to 5 years, the extreme lowest temperature was -49.6 ℃ in Mohe, followed by -49.2 ℃ in Huzhong; the extreme lowest temperature occurs once every 2 years, once every 5 years and once every 10 years in Huzhong, while the extreme lowest temperature occurs once in 20 years, once in 50 years and once in 100 years in Mohe. (3) SCAND teleconnection patterm has a good correlation with extreme cold days in winter(January, February and December)in the Greater Khingan Mountains region. Positive growth of the circulation mode, it has great influence on the extreme cold weather in winter in the Greater Khingan Mountains region. © 2022 Science Press (China). 相似文献
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春季土壤湿度是影响东北粮食产量和品质的重要因素。在气候变暖的背景下,东北春季土壤湿度如何变化,鲜有研究。本文基于1983—2019年黑龙江省22个农业气象站的土壤湿度和气象观测资料,采用方差分析、突变分析及空间分析等方法,分析20世纪80年代以来黑龙江省春季土壤湿度的时空变化特征及其影响因素。结果表明：1983—2019年黑龙江省春季0~30 cm土壤湿度均值为88.22%,0~10 cm、10~20 cm、20~30 cm土层土壤湿度平均值分别为82.63%、89.66%、92.36%,土壤湿度随深度增加而增加,各层均未出现干旱状态。但各层土壤湿度均出现极显著下降趋势,21世纪最初10年较20世纪80年代各层土壤湿度下降6%~15%,在20世纪80年代末进入偏干期。黑龙江省春季土壤湿度呈现由东到西逐渐减小的趋势,32%左右的观测站点呈现显著下降趋势,主要集中在黑龙江省西部及东部地区。前秋季降水量、积雪期长度和积雪初日是影响各层及各月份土壤湿度最重要的因素,其对土壤湿度的影响能持续到5月份,并能影响到20~30 cm。积雪深度及积雪终日对4月份表层土壤湿度有重要影响。地表温度、日平均气温、日平均风速和降水量也是影响不同时期不同深度土壤湿度的关键因素。 相似文献
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