干旱区研究

干旱区研究 ›› 2023, Vol. 40 ›› Issue (4): 532-542.doi: 10.13866/j.azr.2023.04.02

• 天气与气候 • 上一篇    下一篇

不同时间尺度海温因子对西北地区东部夏季降水的影响及预测

张雯1,2(),马阳1,2,王岱1,2(),杨建玲1,3,崔洋1,3   

  1. 1.中国气象局旱区特色农业气象灾害监测预警与风险管理重点实验室，宁夏 银川 750002
    2.宁夏回族自治区气候中心，宁夏 银川 750002
    3.宁夏气象科学研究所，宁夏 银川 750002
  • 收稿日期:2022-09-06 修回日期:2022-12-04 出版日期:2023-04-15 发布日期:2023-04-28
  • 通讯作者: 王岱. E-mail: wangd123@126.com
  • 作者简介:张雯（1990-），女，硕士，工程师，主要从事短期气候预测、气候变化研究. E-mail: acaimeme@sina.cn
  • 基金资助:
    宁夏自然科学基金(2022AAC03674);宁夏自然科学基金(2022AAC05065);中国气象局科技创新发展专项(CXFZ2021J024)

The influence and prediction of SST predictors at different timescales on summer precipitation over the eastern part of Northwest China

ZHANG Wen1,2(),MA Yang1,2,WANG Dai1,2(),YANG Jianling1,3,CUI Yang1,3   

  1. 1. Key Laboratory for Meteorological Disaster Monitoring and Early Warning and Risk Management of Characteristic Agriculture in Arid Regions, China Meteorological Administration, Yinchuan 750002, Ningxia, China
    2. Ningxia Hui Autonomous Region Climate Center, Yinchuan 750002, Ningxia, China
    3. Ningxia Institute of Meteorological Sciences, Yinchuan 750002, Ningxia, China
  • Received:2022-09-06 Revised:2022-12-04 Online:2023-04-15 Published:2023-04-28

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摘要：

利用1961—2020年中国西北地区东部夏季降水量月平均资料、NCEP/NCAR环流再分析以及英国Hadley逐月海表温度（SST）资料，采用功率谱、合成分析、多元线性回归等，分析了西北地区东部夏季年代际、年际降水分量的主导海温模态，并利用时间尺度分离前后得到海温因子分别建立降水预测模型。结果表明：（1） 西北地区东部夏季降水不仅具有30 a左右的年代际震荡周期，还具有准3 a的年际周期，其中降水的年代际分量由太平洋十年际涛动（IPO）主导，春、夏季IPO正位相时，有利于西北地区东部夏季降水处于偏多的背景；反之，处于降水偏少背景。（2） 降水年际分量的主导信号来自热带印度洋、热带西太平洋和北大西洋，当春季热带印度洋呈类全区一致海温模（IOBW）负（正）位相、类北大西洋三极子（NAT）为正（负）位相及热带西太平洋为冷（暖）海温异常时，有利于夏季中高纬贝加尔湖地区出现高（低）压异常，西太平洋副热带高压偏弱（强）、偏南（北），西北地区东部降水易偏少（多）。（3） 独立检验时段内，基于时间尺度分离模型的西北地区东部夏季降水年均趋势异常综合评分（Ps）、符号一致率评分（Pc）分别较原始模型提高6%、7%，具有一定的预测能力。

关键词: 时间尺度分离, 海温模态, 西北地区东部, 降水预测

Abstract:

The dominant sea surface temperature anomaly (SSTa) modes of decadal and interannual variations in summer precipitation over the eastern part of Northwest China (ENC) were here analyzed by power spectrum and composite analyses. The summer precipitation averaged at 155 stations over the ENC, the monthly SSTa, and circulation reanalysis data from 1961 to 2020 were used. The SSTa predictors before and after the timescale decomposition were obtained to establish precipitation prediction models by using linear regression. The results showed that the summer precipitation over the ENC has not only an decadal period of about 30 years but also a 3-year interannual cycle. The Pacific Decadal Oscillation (IPO) has played a leading role in decadal variations in summer precipitation. The positive phase of IPO in the precedent spring is conducive to more precipitation; meanwhile, it is in the background of less precipitation. The tropical Indian Ocean, the tropical western Pacific, and the North Atlantic provide interannual SSTa signals. The negative (positive) phase of tropical Indian Ocean SSTa, the positive (negative) phase of the Atlantic tripole SSTa, and the cold (warm) SSTa in the tropical western Pacific Ocean in the precedent spring, corresponding to the high (low) pressure anomalies over Lake Balkhash in mid- to high latitudes, with northward (southward) and weak (strong) characteristics in the subtropical High over the Western Pacific, favor less (more) summer precipitation over the ENC. Moreover, taking the decadal and interannual variations of SSTa into account can potentially contribute to improving forecasting of summer precipitation over the ENC, with the annual average Ps and Pc scores during the independent test samples based on the scale decomposition model being 6% and 7% higher than those in the original model, respectively.

Key words: time-scale decomposition, sea surface temperature mode, the eastern part of Northwest China, precipitation prediction