1961—2018年四川盆地极端伏旱日数准2 a周期变化特征及其可能成因

doi:10.11755/j.issn.1006-7639(2021)-05-0727

摘要/Abstract

摘要：

利用1961—2018年四川盆地103站的气象干旱综合指数,采用多锥度奇异值分解、经验正交函数分解等方法,分析四川盆地极端伏旱日数准2 a周期的时空变化特征及其可能的形成原因。结果表明:近58 a来,四川盆地极端伏旱日数的主模态为全区一致变化型,且有明显的年际和年代际变化特征,2.3~2.5 a的年际振荡周期最为显著。准2 a周期的典型循环表现出四川盆地极端伏旱日数多寡交替的循环振荡,大值中心出现在盆地中部,与主模态空间型基本一致,但准2 a周期信号并非一直存在,20世纪60年代末到80年代初信号最强。准2 a周期典型循环的第一年,西太平洋副热带高压脊线和副热带西风急流轴线位置均偏北,四川盆地处于日本南部到中国华南西部水汽异常输送带的西部,并出现异常辐散,不利于降水产生,导致四川盆地极端伏旱日数偏多;第二年的大气环流异常情况与第一年相反,极端伏旱日数偏少。

关键词: 四川盆地, 极端伏旱日数, 准2 a周期, 多锥度奇异值分解, 可能成因

Abstract:

Based on MCI (meteorological drought composite index) at 103 stations of Sichuan Basin from 1961 to 2018, the temporal and spatial variation characteristics of extreme summer drought days (ESDD) in quasi-biennial period and its possible causes in Sichuan Basin were analyzed by using MTM-SVD (multi taper method and singular value decomposition) and EOF (empirical orthography function), etc. The results show that the main mode of ESDD in Sichuan Basin appeared the same variation in the whole region, the interannual and interdecadal variation characteristics were obvious, and the interannual oscillation periods with 2.3-2.5 a were the most significant in recent 58 years. The typical cycle with quasi-biennial period showed the more or less ESDD oscillated alternatively in Sichuan Basin, and the large value center appeared in the middle of the basin, which was basically consistent with the main mode of EOF. However, the quasi-biennial period signal of ESDD in Sichuan Basin did not always exist from 1961 to 2018, and the signal was the strongest from the late 1960s to the early 1980s. In the first year of typical cycle with quasi-biennial period, the locations of the western Pacific subtropical high ridge line and the subtropical westerly jet axis were to the north, Sichuan Basin located in the west of vapor abnormal transport belt from the south of Japan to the west of South China, and there was abnormal divergence, which wasn’t conducive to the formation of precipitation, further led to more ESDD. The anomaly distribution of atmospheric circulation in the second year was opposite to that in the first year, and ESDD was less.

Key words: Sichuan Basin, extreme summer drought days, quasi-biennial period, MTM-SVD, possible causes

中图分类号:

P426.616

周斌,王春学,张顺谦. 1961—2018年四川盆地极端伏旱日数准2 a周期变化特征及其可能成因[J]. 干旱气象, 2021, 39(5): 727-733.

ZHOU Bin,WANG Chunxue,ZHANG Shunqian. Quasi-biennial Period Characteristics of Extreme Summer Drought Days and Its Possible Causes in Sichuan Basin During 1961-2018[J]. Journal of Arid Meteorology, 2021, 39(5): 727-733.

图/表 10

表1 气象干旱综合指数等级划分标准

Tab.1 Classification standard of meteorological drought composite index grades

等级	类型	MCI
1	无旱	MCI>-0.5
2	轻旱	-1.0<MCI≤-0.5
3	中旱	-1.5<MCI≤-1.0
4	重旱	-2.0<MCI≤-1.5
5	特旱	MCI≤-2.0

图1 1961—2018年四川盆地极端伏旱日数EOF分解的第一模态空间分布(a)及其对应的时间系数(b)

Fig.1 The spatial distribution of the first mode of extreme summer drought days decomposed by EOF (a) and its corresponding time coefficient (b) in Sichuan Basin from 1961 to 2018

图2 1961—2018年四川盆地极端伏旱日数的线性趋势空间分布[单位:d·(10 a)-1] (浅、深色区分别通过α=0.1、0.05的显著性检验)

Fig.2 Spatial distribution of linear trends of extreme summer drought days in Sichuan Basin during 1961-2018 (Unit: d·(10 a)-1) (The light and dark areas passed significance test of 0.1 and 0.05 levels, respectively)

图3 1961—2018年四川盆地极端伏旱日数的LFV谱 (虚线为蒙特卡洛置信度)

Fig.3 The LFV spectrum of extreme summer drought days in Sichuan Basin during 1961-2018 (the dashed lines for Monte Carlo confidence)

图4 1961—2018年四川盆地极端伏旱日数的准2 a周期典型循环重建(单位:d) (a)0°位相,(b)180°位相

Fig.4 The reconstruction of extreme summer drought days with typical quasi-biennial period in Sichuan Basin during 1961-2018 (Unit: d) (a) 0° phase, (b) 180° phase

图5 1961—2018年四川盆地射洪站极端伏旱日数的准2 a周期重建

Fig.5 The reconstruction of extreme summer drought days with quasi-biennial period at Shehong station of Sichuan Basin during 1961-2018

图6 四川盆地极端伏旱日数EOF第一模态时间系数的滑动t检验

Fig.6 The sliding t test of time coefficient of the EOF1 mode of extreme summer drought days in Sichuan Basin

图7 四川盆地伏旱期间500 hPa平均位势高度场(a)及极端伏旱日数在准2 a周期上0°位相(b)和180°位相(c)重建的500 hPa高度距平场(单位:gpm) (粗黑色线为四川盆地边界,下同)

Fig.7 The average geopotential height field on 500 hPa (a) during summer drought period and 500 hPa geopotential height anomaly field reconstructed by MTM-SVD at 0° (b) and 180° (c) phase of extreme summer drought days in quasi-biennial period over Sichuan Basin (Unit: gpm) (the thick black line for the boundary of Sichuan Basin, the same as below)

图8 四川盆地伏旱期间200 hPa平均纬向风场(a)及极端伏旱日数在准2 a周期上0°位相(b)和180°位相(c)重建的200 hPa纬向风距平场(单位:m·s-1)

Fig.8 The average zonal wind field on 200 hPa (a) during summer drought period and 200 hPa zonal wind anomaly field reconstructed by MTM-SVD at 0° (b) and 180° (c) phase of extreme summer drought days in quasi-biennial period over Sichuan Basin (Unit: m·s-1)

图9 四川盆地极端伏旱日数在准2 a周期上重建的1000~300 hPa水汽输送通量距平场(矢量,单位:kg·m-1·s-1)及其散度距平(阴影,单位:10-5 kg·m-2·s-1) (a)0°位相,(b)180°位相

Fig.9 The water vapor transport flux anomaly field (vectors, Unit: kg·m-1·s-1) and its divergence anomaly (shadows, Unit: 10-5 kg·m-2·s-1) from 1000 hPa to 300 hPa reconstructed by MTM-SVD of extreme summer drought days in quasi-biennial period over Sichuan Basin (a) 0° phase, (b) 180° phase

参考文献 24

[1]	任福民, 龚志强, 王艳姣, 等. 中国干旱、强降水、高温和低温区域性极端事件[M]. 北京: 气象出版社, 2015.
[2]	詹兆渝. 中国气象灾害大典: 四川卷[M]. 北京: 气象出版社, 2006.
[3]	张顺谦, 冯建东. 四川盛夏伏旱的MODIS遥感监测方法[J]. 高原山地气象研究, 2012, 32(1):51-55.
[4]	王素艳, 游超, 何潇. 2006年四川盆地旱情及其对农业的影响评估[J]. 中国农业气象, 2008, 29(1):115-118.
[5]	刘富明, 李跃清. 川东盛夏伏旱非绝热热流量场特征[J]. 大气科学, 1994, 18(4):423-430.
[6]	陈忠明, 闵文彬. 青藏高原地面加热场与四川主汛期降水及伏旱关系[J]. 成都气象学院学报, 1999, 14(1):1-7.
[7]	芮景新. 四川省2002年伏旱成因分析[J]. 气象科技, 2004, 32(增刊):33-35.
[8]	刘晓冉, 杨茜, 程炳岩. 2006年川渝伏旱同期环流场和水汽场异常特征分析[J]. 气象, 2009, 35(8):27-34.
[9]	杨小波, 杨淑群, 马振峰. 夏季东亚副热带西风急流位置对川渝地区降水的影响[J]. 高原气象, 2014, 33(2):384-393.
[10]	张顺谦, 侯美亭, 王素艳. 基于信息扩散和模糊评价方法的四川盆地气候干旱综合评价[J]. 自然资源学报, 2008, 23(4):713-723.
[11]	张驰, 唐红玉, 吴遥, 等. 两种干旱指数在重庆极端干旱事件中的应用[J]. 西南大学学报(自然科学版), 2019, 41(11):92-103.
[12]	巫娜, 罗凝谊, 许勇. 四川盆地干旱灾害统计特征[J]. 气象科技, 2014, 42(2):309-313.
[13]	MANN M E, PARK J. Global-scale modes of surface temperature variability on interannual to century timescales[J]. Journal of Geophysical Research: Atmospheres, 1994, 99(D12):25 819-25 833. DOI URL
[14]	魏凤英. 现代气候统计诊断与预测技术[M]. 2版. 北京: 气象出版社, 2007.
[15]	HAN X, WEI F Y, TOURRE Y M, et al. Spatio-temporal variability of Northern Hemispheric Sea Level Pressure (SLP) and precipitation over the mid-to-low reaches of the Yangtze River[J]. Advances in Atmospheric Sciences, 2008, 25(3):458-466. DOI URL
[16]	王春学, 马振峰, 王佳津, 等. 华西秋雨准4年周期特征及其与赤道太平洋海表温度的关系[J]. 大气科学, 2015, 39(3):643-652.
[17]	王春学, 秦宁生, 周斌, 等. 近400年澜沧江源区年平均流量周期特征及其对厄尔尼诺的响应[J]. 第四纪研究, 2020, 40(1):238-251.
[18]	李潇, 李栋梁, 王颖. 中国西北东部汛期降水对青藏高原东部春季感热在准3 a周期上的响应[J]. 气象学报, 2015, 73(4):737-748.
[19]	中国气象局. 气象干旱等级: GB/T 20481—2017[S]. 北京: 中国标准出版社, 2017.
[20]	廖要明, 张存杰. 基于MCI的中国干旱时空分布及灾情变化特征[J]. 气象, 2017, 43(11):1402-1409.
[21]	曲学斌, 杨钦宇, 王慧清, 等. 基于MCI的内蒙古气象干旱强度特征分析[J]. 气象与环境科学, 2019, 42(4):47-54.
[22]	高睿娜, 王素艳, 高娜, 等. CI和MCI干旱指数在宁夏的适应性对比[J]. 干旱气象, 2021, 39(2):185-192.
[23]	武荣盛, 侯琼, 杨玉辉, 等. 多时间尺度气象干旱指数在内蒙古典型草原的适应性研究[J]. 干旱气象, 2021, 39(2):177-184.
[24]	NORTH G R, BELL T L, CAHALAN R F, et al. Sampling errors in the estimation of empirical orthogonal functions[J]. Monthly Weather Review, 1982, 110:699-706. DOI URL