双月刊

ISSN 1006-9895

CN 11-1768/O4

基于热带和热带外独立影响途径的中国东部 冬季阴天频次的季节预测
作者:
作者单位:

南京信息工程大学

作者简介:

通讯作者:

基金项目:

国家重点研发计划课题(2018YFC1505601)


Seasonal prediction of the variation of the winter cloudy day frequency in eastern China based on the tropical and ex-tropical influence routes
Author:
Affiliation:

Nanjing University of Information Science and Technology

Fund Project:

  • 摘要
  • |
  • 图/表
  • |
  • 访问统计
  • |
  • 参考文献
  • |
  • 相似文献
  • |
  • 引证文献
  • |
  • 资源附件
    摘要:

    本文利用中国东部1078个测站1961-2003年逐日云量数据资料,揭示了中国东部冬季阴天频次主模态的时空分布特征,探讨了其形成的两条独立影响途径,并根据影响机理建立了季节预测模型。结果表明:(1)中国东部冬季阴天频次的经验正交函数分解第一模态独立且显著,解释了其59%的总方差。该模态基本呈现空间一致型的分布,表现出显著的年际变率特征。当该模态为正位相时,北太平洋对流层低层存在显著的大尺度反气旋环流异常,其西侧异常偏南风能够将热带海洋的水汽输送至中国东部地区,导致该地区阴天频次增多;(2)前期8月和9月北太平洋副热带持续性海温异常的纬向偶极型分布(NPD)和副热带北大西洋海平面气压9至11月的短期变化(LPA)是该模态的两个主要驱动因子。当NPD中的西极为冷异常时,在局地低层气旋性异常环流的作用下冷海温异常向南平流,发展至热带西太平洋。而当热带西太平洋冷海温异常形成后,皮耶克里斯反馈作用能够发展和维持太平洋“西冷东暖”海表温度异常分布。“西冷东暖”的海表温度异常导致的热带纬向偶极型对流异常能够进一步激发北太平洋“北正南负”的偶极型高度场异常。北部反气旋异常西侧的偏南风有利于水汽输送至中国东部,从而导致阴天频次增多;LPA主要反映的是中高纬准定常罗斯贝波列由秋季至冬季的迅速转变。当副热带北大西洋海表面气压在前秋由正转负时,罗斯贝波列在东北亚上空冬季形成准正压的异常反气旋,其西侧偏南风异常同样能够导致中国东部阴天频次增多;(3)依据以上热带和热带外的两条独立影响机理途径,我们建立了具有物理意义的季节预测模型,利用2004-2013年间数据进行独立预测获得良好预测效果,可供业务预测部门参考和借鉴。

    Abstract:

    Based on the daily cloud cover derived from the 1078-gauge stations in eastern China during 1961-2003, the temporal-spatial characteristics of the leading mode of winter cloudy day frequency (CDF) over eastern China are revealed via Empirical Orthogonal Function analysis. We revealed the two influence routes of this leading mode, based on which the physical-motivated empirical model is conducted to the seasonal prediction of the winter CDF in eastern China. The results show that: (1) the first EOF mode of winter CDF explains the 59% of the total variance, which is significant and independent from the other modes. This mode mainly shows a homogenous spatial pattern over eastern China and presents a dominant interannual variability. In the positive phase of this mode, a significant lower-level anticyclonic circulation anomaly appears over North Pacific. The anomalous southerly wind over the western flank of the anticyclonic could transport water vapor from tropical ocean to eastern China, leading to increased CDF; (2) the preceding persistent North Pacific subtropical SSTA dipole pattern (NPD) during August and September, and lowing of sea level pressure over midlatitude North Atlantic (LPA) from September to November are the two independent drivers for the formation and variation of this mode. The cold SSTA in the western pole of the NPD is advected southward to the tropical western Pacific by the anomalous northerly of the local low-level anomalous cyclone, and the Bjerknes feedback is then formed which further maintains and accelerates “west cold east warm” zonal SSTA dipole pattern in tropical Pacific. This tropical Pacific zonal SSTA pattern stimulates zonal convection dipole, which further induces a meridional atmospheric teleconnection in the North Pacific. The southerly over the west of the anomalous North Pacific anticyclone is conducive to more CDF in eastern China. The LPA reflects the transition of quasi-stationary Rossby wave train in mid-high latitudes Eurasia from autumn to winter. In winter, the southerly on the west of the barotropic anticyclonic anomaly over the Northeast Asia, the terminal of the Rossby wave train, could also results in more CDF in eastern China; (3) Based on these two independent routes of physical mechanisms from both tropics and ex-tropics, a physics-motivated empirical model is conducted, which shows encouraging independent prediction skill during the ten years of 2004-2013. The results therein are useful references for operational departments on seasonal prediction.

    参考文献
    相似文献
    引证文献
引用本文
分享
文章指标
  • 点击次数:
  • 下载次数:
  • HTML阅读次数:
  • 引用次数:
历史
  • 收稿日期:2021-07-08
  • 最后修改日期:2021-12-13
  • 录用日期:2022-01-24
  • 在线发布日期: 2022-02-24
  • 出版日期: