用华山气象站1985—2014年气象要素资料,分析近30 a华山云海的变化及云海与降水、相对湿度、风速的关系。结果表明,华山年平均云海日为26.27 d,最多年份72 d,最少年份仅3 d;面积<200 km 2云海年平均日数24.23 d;面积≥200 km 2云海...用华山气象站1985—2014年气象要素资料,分析近30 a华山云海的变化及云海与降水、相对湿度、风速的关系。结果表明,华山年平均云海日为26.27 d,最多年份72 d,最少年份仅3 d;面积<200 km 2云海年平均日数24.23 d;面积≥200 km 2云海平均日数2.87 d,最多有20 d(1985、1994年),最少有2 d(1997年),1997年后再没有面积≥200 km 2的云海出现。云海的出现呈逐年下降的趋势,年际差异明显。秋季云海出现日数最多(平均云海日数8.13 d),冬季最少(平均4.60 d);各月的云海日数8月最多,5月最少。面积≥200 km 2云海冬季出现日数最多,夏季最少;11月出现最多,3、12月次之,5月最少。面积≥200 km 2云海出现的前一天或当天一般都有降水,两天中至少有一天出现降水的几率是84.30%;平均相对湿度≥70%时,较易形成云海;云海日出现时常伴有风,但总体风速不大,通常≤10.0 m·s-1,利于云海的形成保持。展开更多
Based on data of daily air temperature during 1951-2013,long-term variation characteristics of cooling degree days( CDD) in Xi'an and Chang'an in summer were analyzed by using CDD to evaluate cooling energy consum...Based on data of daily air temperature during 1951-2013,long-term variation characteristics of cooling degree days( CDD) in Xi'an and Chang'an in summer were analyzed by using CDD to evaluate cooling energy consumption and 26 ℃ as the basic temperature of CDD. The results indicated that the changing trends of CDD in Xi'an and Chang'an were basically identical within a year,and the demand for cooling refrigeration was large mainly from June to August,especially in July. The maximum of urban-rural difference of CDD between Xi'an and Chang'an appeared in June.In order to achieve the same temperature,energy needed by the urban area was 5-7 ℃·d more than the suburb from June to August. Temperature and the cooling energy consumption were closely related,and the correlation degree increased with the rise of temperature. The effects of temperature increase of 1 ℃ on cooling energy consumption rate in Xi'an were more obvious than that in Chang'an. In both Xi'an and Chang'an,the effects of temperature increase of 1 ℃ on cooling energy consumption rate in July and August were greater than that in May,June and September.Evaluation models of cooling energy consumption in summer in Xi'an and Chang'an were built using temperature anomaly and CDD variability and can be applied to business systems.展开更多
文摘用华山气象站1985—2014年气象要素资料,分析近30 a华山云海的变化及云海与降水、相对湿度、风速的关系。结果表明,华山年平均云海日为26.27 d,最多年份72 d,最少年份仅3 d;面积<200 km 2云海年平均日数24.23 d;面积≥200 km 2云海平均日数2.87 d,最多有20 d(1985、1994年),最少有2 d(1997年),1997年后再没有面积≥200 km 2的云海出现。云海的出现呈逐年下降的趋势,年际差异明显。秋季云海出现日数最多(平均云海日数8.13 d),冬季最少(平均4.60 d);各月的云海日数8月最多,5月最少。面积≥200 km 2云海冬季出现日数最多,夏季最少;11月出现最多,3、12月次之,5月最少。面积≥200 km 2云海出现的前一天或当天一般都有降水,两天中至少有一天出现降水的几率是84.30%;平均相对湿度≥70%时,较易形成云海;云海日出现时常伴有风,但总体风速不大,通常≤10.0 m·s-1,利于云海的形成保持。
基金Supported by Foundation for Young Scholars of Shaanxi Meteorological Bureau in 2016 and 2017(2016Y-7,2017Y-11)
文摘Based on data of daily air temperature during 1951-2013,long-term variation characteristics of cooling degree days( CDD) in Xi'an and Chang'an in summer were analyzed by using CDD to evaluate cooling energy consumption and 26 ℃ as the basic temperature of CDD. The results indicated that the changing trends of CDD in Xi'an and Chang'an were basically identical within a year,and the demand for cooling refrigeration was large mainly from June to August,especially in July. The maximum of urban-rural difference of CDD between Xi'an and Chang'an appeared in June.In order to achieve the same temperature,energy needed by the urban area was 5-7 ℃·d more than the suburb from June to August. Temperature and the cooling energy consumption were closely related,and the correlation degree increased with the rise of temperature. The effects of temperature increase of 1 ℃ on cooling energy consumption rate in Xi'an were more obvious than that in Chang'an. In both Xi'an and Chang'an,the effects of temperature increase of 1 ℃ on cooling energy consumption rate in July and August were greater than that in May,June and September.Evaluation models of cooling energy consumption in summer in Xi'an and Chang'an were built using temperature anomaly and CDD variability and can be applied to business systems.