摘要
基于2015—2017年6—8月鄱阳湖周边共340个气象站的逐小时气温观测资料和NASA MERRA再分析资料,应用经验正交函数分解(EOF)和热量方程诊断方法,分析了鄱阳湖地区夏季气温的日变化特征及其形成原因。结果表明:受非绝热加热影响(包括地表感热和地表向上的长波辐射),EOF第一特征向量反映鄱阳湖区与周围陆地的气温呈同相变化。04—17时,湖区和周围陆地气温逐渐升高,湖区滞后于周围陆地,湖区为冷源;17时—次日04时,湖区和周围陆地气温逐渐降低,湖区同样滞后于周围陆地,湖区为热源。受热扩散影响,EOF第二特征向量反映鄱阳湖区与周围陆地的气温呈反相变化,因湖区和周围陆地气温分布不均匀,22时—次日11时,湖体表面大气热量向周围陆地表面大气扩散,湖体表面气温降低,陆地表面气温升高;11—22时,反之。因此,鄱阳湖水体的存在对毗邻地区的气温产生影响,在一定程度上改变了局地气候。
Based on the observational hourly air temperature data of 340 stations during summer in 2015-2017 around Poyang Lake and NASA MERRA reanalysis data,the diurnal variation characteristics of air temperature in Poyang Lake area and the causes were discussed using the EOF method and equation diagnostic analysis method.The results showed that under the impact of non-adiabatic heating(including surface sensible heat and upward surface long wave radiation),EOF1 reflected that the air temperatures of Poyang Lake area and the surrounding land changed simultaneously.The air temperatures of the lake area and surrounding land gradually increased during 04:00-17:00 BT,the warming rate of temperature in lake area was slower than that in the surrounding land,thus the lake area became a cooling source;the air temperature of both two areas decreased gradually during 17:00-04:00 BT,the cooling rate of temperature in the lake area was slower than that of surrounding land,and the lake area became a heating source.Affected by the thermal diffusion,EOF2 reflected air temperatures in lake area and the surrounding land changed oppositely.Due to the uneven distribution of the air temperature in two areas,the thermal energy of the lake surface diffused to the surrounding land surface during 22:00 BT and 11:00 BT,the air temperature over the lake surface decreased and the temperature over the land surface increased;while the situation was on the contrary from 11:00 BT to 22:00 BT.Therefore,the surrounding areas were affected by Poyang Lake,which might change the local climate to a certain extent.
作者
吴楠
邹海波
占龙飞
Wu Nan;Zou Haibo;Zhan Longfei(Jiangxi Meteorological Disaster Emergency Warning Center,Nanchang 330096,China;Jiangxi Meteorological Science Institute,Nanchang 330096,China;Jiangxi Climate Center,Nanchang 330096,China)
出处
《气象与减灾研究》
2019年第4期270-276,共7页
Meteorology and Disaster Reduction Research
基金
国家自然科学基金资助项目(编号:41865003).
关键词
夏季气温
鄱阳湖区
日变化
EOF
成因
air temperature in summer
Poyang Lake area
diurnal variation
EOF
cause
