Journal of Arid Meteorology ›› 2019, Vol. 37 ›› Issue (2): 233-242.DOI: 10.11755/j.issn.1006-7639(2019)-02-0233

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Causes of Heat Wave Weather in Shaanxi in July 2017 and Preceding Signals

LIU Jiahuimin1, ZHENG Ran2, LOU Panxing1, LIANG Mian1   

  1. 1. Shaanxi Meteorological Observatory, Xi’an 710014, China;
    2. Climate Center of Sichuan Province, Chengdu 610072, China
  • Online:2019-04-30 Published:2019-04-30



  1. 1.陕西省气象台,陕西 西安 710014;
    2.四川省气候中心,四川 成都 610072
  • 作者简介:刘嘉慧敏(1989— ),女,陕西宝鸡人,工程师,硕士,主要从事灾害性天气预报技术研究. E-mail:。
  • 基金资助:

Abstract: Based on the daily maximum temperature from 98 weather stations of Shaanxi Province and monthly reanalysis data from NCEP/NCAR, sea surface temperature (SST) from NOAA, and circulation indexes from National Climate Center of China, the causes of extremely high temperature weather process in Shaanxi in July 2017 were analyzed, and the preceding signals were discussed. The results show that the extremely high temperature weather process lasted for nearly 20 days in July 2017 in Shaanxi, and its intensity was the second level since 1961. The process of high temperature event was divided into two stages. The high temperature at the first stage occurred in the north and central part of Shaanxi from 9 to 14 July 2017, while at the second stage it expanded southward to the south of Shaanxi from 19 to 27 July 2017, and the intensity reached the maximum. At the first stage of high temperature, the most areas of Shaanxi were in positive geopotential height anomaly field from Xinjiang to Hetao area. The anomalous strong sinking movement and northerly warm advection in low level caused the high temperature weather. At the second stage, the western Pacific subtropical high (WPSH) obviously moved to the north and the west, the upper-level jet stream and the South Asian high (SAH) travelled clearly eastward, which led to the enhancement of the anomalous sinking motion and moving southward, combined with the increase of warm advections intensity and range in low level, further made the high temperature to expand southward and its intensity reached the maximum. In addition, the study found that the anomaly of previous SST from May to June in the key area of tropical western Pacific (10°S-15°N, 160°E-140°W) was significantly positive correlated with high temperature in the south and central of Shaanxi in July, so it was a reliable preceding signal to forecast high temperature. When the previous SST from May to June was higher in the key area, SST connected with WPSH, SAH and zonal wind over East Asia via exciting wave train in teleconnection, which affected the temperature change in central and southern Shaanxi, it might be the main reason of extremely high temperature event in this area in July.

Key words: high temperature, WPSH, SAH, SST, abnormal anticyclonic

摘要: 利用陕西98个气象观测站最高气温逐日资料和NCEP/NCAR再分析逐日、逐月资料、NOAA逐月海表温度资料以及国家气候中心逐月环流指数资料,分析了2017年7月陕西极端高温热浪天气的成因,探寻其前期信号。结果表明:此次高温演变过程分为两个阶段,第一阶段为9—14日,陕西大部处于新疆至河套一带高度场正异常控制中,异常下沉运动和低层暖平流位置偏北造成陕西中北部出现高温;第二阶段为19—27日,西太平洋副热带高压明显北抬西伸、高空急流与南亚高压东进,造成异常下沉运动增强、南移,加之低层暖平流范围增大、强度增强,使得高温向陕西南部扩展,高温中心南移且强度增大。前期5—6月赤道西太平洋关键区(10°S—15°N、160°E—140°W)海温异常与7月陕西中南部高温呈显著正相关,它是7月陕西中南部高温一个可靠的前期信号。当前期5—6月关键区海温偏高时,其可通过激发遥相关波列与西太副高、南亚高压及东亚上空纬向风发生联系,进而影响陕西中南部气温变化,这可能是造成该地区7月极端高温事件的主要原因。

关键词: 高温, 西太平洋副热带高压, 南亚高压, 海温, 异常反气旋

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