Similarities and Differences of ISO Activity Characteristics over the Tropical Indian Ocean and Pacific
-
摘要: 基于再分析资料,对比分析了热带印度洋和太平洋地区大气季节内振荡(ISO)活动特征的异同。结果表明:印度洋和西太平洋地区ISO活动中心在4月和10月存在季节性跳跃,并且ISO在西太平洋地区活动中心位置南北跳跃的经向距离较印度洋偏大。ISO较强的活动中心也是ISO强度年较差较大的地区,并且各个活动中心ISO强度达到最强的时间存在明显的差异。ISO活动存在显著的年际和年代际变化,在20世纪80年代ISO的活动强度和变化趋势都存在一个明显的转折。夏季印度洋和西太平洋地区ISO都存在较强的北传,赤道地区印度洋ISO强度较强,而赤道以外地区西太平洋ISO强度较强;并且ISO在西太平洋地区北传的速度较印度洋偏慢。无论是冬季还是夏季,当ISO活跃于印度洋和西太平洋时,ISO的空间分布和垂直结构特征都有着明显的差异。Abstract: The characteristics of atmospheric Intraseasonal Oscillation (ISO) activity over the tropical Indian Ocean and the Pacific are compared based on the reanalysis data. The results show seasonal jumps in the ISO activity centers over the Indian Ocean and the western Pacific in April and October. In addition, the meridional jumping distance of the ISO activity center over the western Pacific is larger than that over the Indian Ocean. The activity centers of stronger ISO are also the areas with greater annual amplitude in ISO intensity, and the ISO intensity of each activity center reached the peak at significantly different times. Considerable interannual and interdecadal variation is observed in ISO activity, and the intensity and variation trend of ISO show an obvious turning point in the 1980s. In summer, a strong northward propagation of ISO occurs over the Indian Ocean and the western Pacific. The equatorial ISO over the Indian Ocean is stronger than the ISO beyond the equator, and the ISO beyond the equator over the western Pacific is stronger than the equatorial ISO. Moreover, the northward propagation of ISO is slower over the western Pacific Ocean than over the Indian Ocean. When the ISO is active over the Indian Ocean and Western Pacific in winter and summer, its spatial distribution and vertical structure characteristics are obviously discrepant.
-
图 1 1949~2016年(a、c)夏季和(b、d)冬季ISO强度(a、b)年平均和(c、d)年际标准差。图中矩形区域为文中定义ISO强度指数所使用的区域
Figure 1. (a, b) Intensity and (c, d) annual standard deviation of ISO (intraseasonal oscillation) averaged in (a, c) summer and (b, d) winter from 1949 to 2016. The rectangular region in the figure is the area used to define the ISO strength index in this paper
图 3 1949~2016年平均(a)印度洋(70°E~90°E)和(b)西太平洋(120°E~140°E)区域平均的ISO强度的纬度—时间演变。黑色等值线为2.1 m s−1,黑色虚线为ISO活动强度中心所在位置
Figure 3. Latitude–time distribution of ISO intensity averaged over (a) the Indian Ocean (65°E–95°E) and (b) the western Pacific (105°E–145°E) from 1949 to 2016. The black contour line is 2.1 m s−1, and the dotted black line is the center of ISO activity intensity
图 5 1949~2016年夏季(a)A区域(黑色)和B区域(紫色)、(b)C区域(蓝色)和D区域(绿色)、(c)E区域(红色)平均的ISO强度的年际变化及其线性趋势(图中直线)
Figure 5. Interannual variation in ISO intensity averaged over (a) area A (black) and area B (purple), (b) area C (blue) and area D (green), and (c) area E (red) and its linear trend (straight line in the figure) in summer from 1949 to 2016
图 7 夏季(a、c)印度洋和(b、d)西太平洋ISO指数超前滞后回归的ISO OLR纬度—时间剖面:(a、c)70°E~90°E平均ISO OLR;(b、d)120°E~140°E平均ISO OLR。ISO指数平均的区域分别是:(a)(5°S~10°N,70°E~90°E),(b)(5°S~10°N,120°E~140°E),(c)(10°N~20°N,70°E~90°E),(d)(10°N~20°N,120°E~140°E)。黑色实线表示经向传播速度为1°/d。打点表示通过0.1显著性检验
Figure 7. ISO OLR (W m−2) averaged over the (a, c) 70°E–90°E and (b, d) 120°E–140°E lag regressed onto (a, c) the Indian Ocean and (b, d) western Pacific ISO index in summer, respectively. The average regions of ISO index (a to d) are as follows: (5°S–10°N, 70°E–90°E), (5°S–10°N, 120°E–140°E), (10°N–20°N, 70°E–90°E), (10°N–20°N, 120°E–140°E). The solid black line indicates a meridional velocity of 1°/d. The stipplings indicate the results pass the 0.1 significance test
图 8 夏季印度洋(左列)(5°N~15°N,70°E~90°E)和西太平洋(右列)(5°N~15°N,120°E~140°E)ISO指数回归的各物理量分别在70°E~90°E和120°E~140°E平均的垂直剖面:(a、b)经向风(单位:m s−1);(c、d)位势高度(单位:gpm);(e、f)温度(单位:K);(g、h)垂直速度(单位:10−2 Pa s−1);(i、j)比湿(单位:10−1 g kg−1);(k、l)OLR(单位:W m−2)。打点表示通过0.1显著性检验
Figure 8. Vertical profile of each physical variable averaged over 70°–90°E and 120°–140°E regressed onto the Indian Ocean (left column) ( 5°N–15°N, 70°E–90°E) and western Pacific (right column) (5°N–15°N, 120°E–140°E) ISO index in summer, respectively: (a, b) Meridional wind (m s−1); (c, d) geopotential height (gpm); (e, f) temperature (K); (g, h) vertical velocity (10−2 Pa s−1); (i, j) specific humidity (10−1 g kg−1); (k, l) OLR (W m−2). The stipplings indicate that the results pass the 0.1 significance test
图 9 夏季(a)印度洋(5°N~15°N,70°E~90°E)和(b)西太平洋(5°N~15°N, 120°E~140°E)ISO指数回归的850 hPa水平风场(矢量,单位:m s−1)和OLR(阴影,单位:W m−2)。黑色箭头和打点表示通过0.1显著性检验的风场和OLR
Figure 9. Horizontal wind (vector, units: m s−1) at 850 hPa and OLR (shadow, units: W m−2) regressed onto the ISO index of (a) the Indian Ocean (5°N–15°N, 70°E–90°E) and (b) western Pacific (5°N–15°N, 120°E–140°E) in summer. The black arrows and stipplings indicate the wind field and OLR that pass the 0.1 significance test, respectively
图 10 冬季(a)印度洋(10°S~10°N,70°~90°E)和(b)西太平洋(10°S~10°N,120°E~140°E)ISO指数超前滞后回归的10°S~10°N平均的ISO OLR。打点表示通过0.1显著性检验
Figure 10. ISO OLR averaged over the 10°S–10°N lag regressed onto the ISO index of (a) the Indian Ocean (10°S–10°N, 70°E–90°E) and (b) western Pacific (10°S–10°N, 120°E–140°E) in winter. The stipplings indicate that the results pass the 0.1 significance test
图 11 冬季印度洋(左侧)(10°S~10°N,70°E~90°E)和西太平洋(右侧)(10°S~10°N,120°E~140°E)ISO指数回归的10°S~10°N平均的各物理量的垂直剖面:(a、b)纬向风(单位:m s−1);(c、d)位势高度(单位:gpm);(e、f)温度(单位:K);(g、h)垂直速度(单位:10−2 Pa s−1);(i、j)比湿(单位:10−1 g kg−1);(k、l)OLR(单位:W m−2)。打点表示通过0.1显著性检验
Figure 11. Vertical profile of each physical variable averaged over 10°S–10°N regressed onto the Indian Ocean (left column) (10°S–10°N, 70°–90°E) and western Pacific (right column) (10°S–10°N, 120°–140°E) ISO index in winter, respectively: (a, b) zonal wind (m s−1); (c, d) geopotential height (gpm); (e, f) temperature (K); (g, h) vertical velocity (10−2 Pa s−1); (i, j) specific humidity (10−1 g kg−1); (k, l) OLR (W m−2). The stipplings indicate that the results pass the 0.1 significance test
图 12 冬季(a)印度洋(10°S~10°N,70°E~90°E)和(b)西太平洋(10°S~10°N,120°E~140°E)ISO指数回归的850 hPa风场(矢量,单位:m s−1)和OLR(阴影,单位:W m−2)。黑色箭头和打点表示通过0.1显著性检验的风场和OLR
Figure 12. Horizontal wind (vector, units: m s−1) at 850 hPa and OLR (shadow, units: W m−2) regressed onto the ISO index of (a) the Indian Ocean (10°S–10°N, 70°E–90°E) and (b)western Pacific (10°S–10°N, 120°E–140°E) in winter. The black arrows and stipplings indicate the wind field and OLR that pass the 0.1 significance test, respectively
表 1 夏季和冬季的ISO活动中心的区域
Table 1. Areas of ISO activity centers in summer and winter
区域 夏季ISO活动中心 冬季ISO活动中心 A 10°N~20°N,65°E~95°E 7.5°S~17.5°S,45°E~65°E B 5°S~5°N,75°E~95°E 2.5°S~12.5°S,75°E~100°E C 5°N~20°N,102.5°E~122.5°E 5°S~15°S,110°E~150°E D 5°N~20°N,122.5°E~150°E 2.5°S~10°N,120°E~150°E E 5°N~15°N,95°W~125°W 0°~10°S,160°E~160°W 表 2 夏季和冬季不同区域ISO活动中心强度的线性趋势
Table 2. Linear trend of ISO activity center intensity in summer and winter at different periods
m s−1 (10 a)−1 区域 1949~1979年ISO
强度线性趋势1986~2016年ISO
强度线性趋势夏季 冬季 夏季 冬季 A 0.169 0.157 0.032 −0.088 B 0.199** −0.107 −0.142* −0.107 C 0.198 0.156* 0.136 0.110 D 0.160* −0.053 0.020 −0.060 E 0.219** 0.240* −0.157* −0.061 *和**分别表示通过0.1和0.05显著性检验。 -
[1] 陈雄, 李崇银, 谭言科, 等. 2015. 冬季热带西太平洋MJO活动强弱年的环境场特征[J]. 热带气象学报, 31(1): 1–10Chen Xiong, Li Chongyin, Tan Yanke, et al. The environmental characteristics of strong/weak MJO activity over the tropical western Pacific in winter [J]. J. Trop. Meteor. (in Chinese), 31(1): 1–10. doi: 10.16032/j.issn.1004-4965.2015.01.001 [2] Chen X, Li C Y, Tan Y K. 2015. The influence of El Niño on MJO over the equatorial Pacific [J]. J. Ocean Univ. China, 14(1): 1−8. doi: 10.1007/s11802-015-2381-y [3] Chen X, Li C Y, Tan Y K. 2017. Further inquiry into characteristics of MJO in boreal winter [J]. Int. J. Climatol., 37(12): 4451−4462. doi: 10.1002/joc.5098 [4] 陈兴跃, 王会军, 曾庆存. 2000. 大气季节内振荡及其年际变化[M]. 北京: 气象出版社, 176ppChen Xingyao, Wang Huijun, Zeng Qingcun. 2000. Atmospheric Intraseasonal Oscillation and its Interannual Variation (in Chinese) [M]. Beijing: China Meteorological Press, 176pp. [5] 董敏, 张兴强, 何金海. 2004. 热带季节内振荡时空特征的诊断研究 [J]. 气象学报, 62(6): 821−830. doi: 10.3321/j.issn:0577-6619.2004.06.011Dong Min, Zhang Xingqiang, He Jinhai. 2004. A diagnostic study on the temporal and spatial characteristics of the tropical Intraseasonal Oscillation [J]. Acta Meteor. Sinica (in Chinese), 62(6): 821−830. doi: 10.3321/j.issn:0577-6619.2004.06.011 [6] Duchon C E. 1979. Lanczos filtering in one and two dimensions [J]. J. Appl. Meteor. Climatol., 18(8): 1016−1022. doi: 10.1175/1520-0450(1979)018<1016:LFIOAT>2.0.CO;2 [7] 何洁琳, 段安民, 覃卫坚. 2013. 热带大气季节内振荡与西北太平洋热带气旋活动的季节预测: 统计事实研究 [J]. 气候与环境研究, 18(1): 101−110. doi: 10.3878/j.issn.1006-9585.2012.11075He J L, Duan A M, Qin W J. 2013. Statistics on the modulation of Madden–Julian Oscillation on tropical cyclone activity in the western North Pacific [J]. Climatic Environ. Res. (in Chinese), 18(1): 101−110. doi: 10.3878/j.issn.1006-9585.2012.11075 [8] Hendon H H, Wheeler M C, Zhang C D. 2007. Seasonal dependence of the MJO–ENSO relationship [J]. J. Climate, 20(3): 531−543. doi: 10.1175/JCLI4003.1 [9] Hendon H H, Zhang C D, Glick J D. 1999. Interannual variation of the Madden–Julian Oscillation during austral summer [J]. J. Climate, 12(8): 2538−2550. doi: 10.1175/1520-0442(1999)012<2538:IVOTMJ>2.0.CO;2 [10] Jeong J H, Ho C H, Kim B M, et al. 2005. Influence of the Madden–Julian Oscillation on wintertime surface air temperature and cold surges in East Asia [J]. J. Geophys. Res., 110(D11): D11104. doi: 10.1029/2004JD005408 [11] Jones C, Waliser D E, Lau K M, et al. 2004. Global occurrences of extreme precipitation and the Madden–Julian Oscillation: Observations and predictability [J]. J. Climate, 17(23): 4575−4589. doi: 10.1175/3238.1 [12] Kalnay E, Kanamitsu M, Kistler R, et al. 1996. The NCEP/NCAR 40-year reanalysis project [J]. Bull. Amer. Meteor. Soc., 77(3): 437−472. doi: 10.1175/1520-0477(1996)077<0437:TNYRP>2.0.CO;2 [13] Lau K M, Chan P H. 1986. Aspects of the 40-50 day oscillation during the northern summer as inferred from outgoing longwave radiation [J]. Mon. Wea. Rev., 114(7): 1354−1367. doi: 10.1175/1520-0493(1986)114<1354:AOTDOD>2.0.CO;2 [14] Lau K M, Peng L. 1987. Origin of low-frequency (intraseasonal) oscillations in the tropical atmosphere. Part I: Basic theory [J]. J. Atmos. Sci., 44(6): 950−972. doi: 10.1175/1520-0469(1987)044<0950:OOLFOI>2.0.CO;2 [15] Li C Y. 1985. Actions of summer monsoon troughs (ridges) and tropical cyclones over South Asia and the moving CISK mode [J]. Scientia Sinica (Series B), 28(11): 1197−1206. doi: 10.1360/yb1985-28-11-1197 [16] 李崇银. 2000. 气候动力学引论(第二版)[M]. 北京: 气象出版社, 515pp. Li Chongyin. 2000. Introduction to Climate Dynamics (2nd ed. ) (in Chinese) [M]. Beijing: China Meteorological Press, 515 pp. [17] Li C Y. 1993. A further inquiry on the mechanism of 30–60 day oscillation in the tropical atmosphere [J]. Adv. Atmos. Sci., 10(1): 41−53. doi: 10.1007/BF02656952 [18] Li C Y, Cho H R, Wang J T. 2002. CISK Kelvin wave with evaporation–wind feedback and air–sea interaction—A further study of tropical intraseasonal oscillation mechanism [J]. Adv. Atmos. Sci., 19(3): 379−390. doi: 10.1007/s00376-002-0073-1 [19] Li C Y, Li G L. 1997. Evolution of intraseasonal oscillation over the tropical western Pacific/South China Sea and its effect to the summer precipitation in southern China [J]. Adv. Atmos. Sci., 14(2): 246−254. doi: 10.1007/s00376-997-0023-z [20] 李崇银, 龙振夏, 穆明权. 2003. 大气季节内振荡及其重要作用 [J]. 大气科学, 27(4): 518−535.Li Chongyin, Long Zhenxia, Mu Mingquan. 2003. Atmospheric Intraseasonal Oscillation and its important effect [J]. Chinese J. Atmos. Sci. (in Chinese), 27(4): 518−535. [21] Li C Y, Smith I. 1995. Numerical simulation of the tropical intraseasonal oscillation and the effect of warm SST [J]. Oceanogr. Lit. Rev., 42(9): 726. [22] 李崇银, 周亚萍. 1994. 热带大气季节内振荡和ENSO的相互关系 [J]. 地球物理学报, 37(1): 17−26.Li Chongyin, Zhou Yaping. 1994. Relationship between Intraseasonal Oscillation in the tropical atmosphere and ENSO [J]. Chinese J. Geophys. (in Chinese), 37(1): 17−26. [23] Li T. 2014. Recent advance in understanding the dynamics of the Madden–Julian Oscillation [J]. J. Meteor. Res., 28(1): 1−33. doi: 10.1007/s13351-014-3087-6 [24] Li T M, Wang B. 1994. The influence of sea surface temperature on the tropical Intraseasonal Oscillation: A numerical study [J]. Mon. Wea. Rev., 122(10): 2349−2362. doi: 10.1175/1520-0493(1994)122<2349:TIOSST>2.0.CO;2 [25] Liebmann B, Smith C A. 1996. Description of a complete (interpolated) outgoing longwave radiation dataset [J]. Bull. Amer. Meteor. Soc., 77(6): 1275−1277. [26] Liu F, Li T, Wang H, et al. 2016. Modulation of boreal summer intraseasonal oscillations over the western North Pacific by ENSO [J]. J. Climate, 29(20): 7189−7201. doi: 10.1175/JCLI-D-15-0831.1 [27] Madden R A, Julian P R. 1971. Detection of a 40-50 day oscillation in the zonal wind in the tropical Pacific [J]. J. Atmos. Sci., 28(5): 702−708. doi: 10.1175/1520-0469(1971)028<0702:DOADOI>2.0.CO;2 [28] Madden R A, Julian P R. 1972. Description of global-scale circulation cells in the tropics with a 40-50 day period [J]. J. Atmos. Sci., 29(6): 1109−1123. doi: 10.1175/1520-0469(1972)029<1109:DOGSCC>2.0.CO;2 [29] Madden R A, Julian P R. 1994. Observations of the 40-50-day tropical oscillation—A review [J]. Mon. Wea. Rev., 122(5): 814−837. doi: 10.1175/1520-0493(1994)122<0814:OOTDTO>2.0.CO;2 [30] Marshall A G, Alves O, Hendon H H. 2009. A coupled GCM analysis of MJO activity at the onset of El Niño [J]. J. Atmos. Sci., 66(4): 966−983. doi: 10.1175/2008JAS2855.1 [31] Salby M L, Hendon H H. 1994. Intraseasonal behavior of clouds, temperature, and motion in the Tropics [J]. J. Atmos. Sci., 51(15): 2207−2224. doi: 10.1175/1520-0469(1994)051<2207:IBOCTA>2.0.CO;2 [32] 吴俊杰, 袁卓建, 钱钰坤, 等. 2009. 热带季节内振荡对2008年初南方持续性冰冻雨雪天气的影响 [J]. 热带气象学报, 7(S1): 103−112.Wu Junjie, Yuan Zhuojian, Qian Yukun, et al. 2009. The role of Intraseasonal Oscillation in the southern–China snowstroms during January 2008 [J]. J. Trop. Meteor. (in Chinese), 7(S1): 103−112. [33] Yang H, Li C Y. 2003. The relation between atmospheric Intraseasonal Oscillation and summer severe flood and drought in the Changjiang–Huaihe River basin [J]. Adv. Atmos. Sci., 20(4): 540−553. doi: 10.1007/BF02915497 [34] Zhang C D. 2013. Madden–Julian Oscillation: Bridging weather and climate [J]. Bull. Amer. Meteor. Soc., 94(12): 1849−1870. doi: 10.1175/BAMS-D-12-00026.1 [35] Zhang C D, Dong M. 2004. Seasonality in the Madden–Julian Oscillation [J]. J. Climate, 17(16): 3169−3180. doi: 10.1175/1520-0442(2004)017<3169:SITMO>2.0.CO;2 [36] Zhang L N, Wang B Z, Zeng Q C. 2009. Impact of the Madden–Julian Oscillation on summer rainfall in Southeast China [J]. J. Climate, 22(2): 201−216. doi: 10.1175/2008JCLI1959.1 -