Evaluation of Quasi-biweekly Oscillation Prediction in the Asian Summer Monsoon Regions by BCC S2S Model
-
摘要: 利用1994-2013年ERA-Interim及NCEP/NCAR再分析数据,对国家气候中心(BCC)次季节到季节尺度模式(S2S)1994-2013年的回报试验数据进行亚洲季风区准双周振荡(QBWO)预报能力评估,并诊断模式预报误差来源。结果表明:BCC S2S模式对QBWO的预报能力随着预报提前时间的增长而降低,9 d后预报技巧明显减弱,其周期、传播特征和强度出现误差;在提前9 d预报中,印度洋地区QBWO对流-环流系统结构松散,信号偏弱,对流向东传播,这与印度洋平均态的预报误差有关,夏季对流平均态低层水汽场在西太平洋和阿拉伯海较强,而东印度洋、孟加拉湾一带偏弱;西北太平洋地区QBWO具有向西北传播的特征,但强度偏弱,可能原因是预报低估了QBWO对流西北侧低层涡度的超前信号,经涡度方程诊断发现,地转涡度平流正贡献微弱,相对涡度平流在对流西北侧引发负涡度,从而减弱了对流西北侧由低层正涡度引发的有利条件。Abstract: The quasi-biweekly oscillation (QBWO) plays an important role in global weather and climate change. It's a very important source of sub-seasonal to seasonal (S2S) predictability. Using the sub-seasonal to seasonal forecast model of Beijing Climate Center (BCC S2S), the boreal summer QBWO is simulated, the forecast skill is discussed, and the model bias is analyzed. QBWO can be obtained from the third and fourth modes of multivariate empirical orthogonal function (MV-EOF) analysis on daily anomalies of outgoing longwave radiation (OLR) and zonal wind at 850 hPa (U850) in the Asian monsoon region. According to reanalysis data, QBWO shows a northeast-southwest-tilted convection-circulation structure, propagating north/northwestward from the equatorial western Pacific and Indian Ocean. The forecast skill of BCC S2S on QBWO decreases as the forecast lead time increases, and biases become very significant in the period, propagation characteristics and strength when the lead time comes to 9 days. BCC S2S reveals a higher forecast skill of QBWO structure and propagation over the western North Pacific, while it significantly underestimated convection signal of QBWO over the tropical Indian Ocean. The convection-circulation wave structure of QBWO in 9-day lead time prediction over the Indian Ocean is loose and appears over the Arabian Sea (instead of over the tropical eastern Indian Ocean and Bay of Bengal where the reanalyzed QBWO is active). It suggests that the unrealistic Indian Ocean QBWO is related to biases of model mean state. The simulated low-level moisture and convection during boreal summer are enhanced over the western Pacific and the Arabian Sea. However, the model underestimates the abundant moisture and vigorous convection over the eastern Indian Ocean and Bay of Bengal. BCC S2S captures the structure and propagation of QBWO over the western North Pacific, but slightly underestimates the strength of QBWO wave train. This underestimation of QBWO convection might be attributable to the relatively weaker vorticity to the northwest of QBWO convection. By diagnosing the vorticity equation, it's found that although the model well simulates positive contributions of geostrophic vorticity advection and convergence effects to the northwest of convection, these contributions are still underestimated. Moreover, the simulated relative vorticity advection shows an opposite effect to reanalysis data in the 9-day lead time prediction, weakening the favorable environment of QBWO development associated with positive vorticity to the northwestern part of convection.
-
图 1 1994—2013年夏季(5—10月)季节内尺度MV-EOF的OLR(填色)和850 hPa风场(矢量)的第3和第4模态分布
(a)再分析数据第3模态,(b)模式提前1 d预报第3模态,(c)模式提前6 d预报第3模态,(d)模式提前11 d预报第3模态,(e)模式提前16 d预报第3模态,(f)再分析数据第4模态,(g)模式提前1 d预报第4模态,(h)模式提前6 d预报第4模态,(i)模式提前11 d预报第4模态,(j)模式提前16 d预报第4模态
Fig. 1 The third mode and the fourth mode of intraseasonal OLR(the shaded) with 850 hPa wind(the vector) during boreal summer(May-October) in 1994-2013 based on MV-EOF
(a)the third mode of reanalysis, (b)the third mode of 1 d lead time prediction, (c)the third mode of 6 d lead time prediction, (d)the third mode of 11 d lead time prediction, (e)the third mode of 16 d lead time prediction, (f)the fourth mode of reanalysis, (g)the fourth mode of 1 d lead time prediction, (h)the fourth mode of 6 d lead time prediction, (i)the fourth mode of 11 d lead time prediction, (j)the fourth mode of 16 d lead time prediction
图 6 1994—2013年夏季(5—10月)气候平均分布(a)再分析数据OLR,(b)模式提前9 d预报OLR,(c)再分析数据700~1000 hPa比湿,(d)模式提前9 d预报700~1000 hPa比湿
Fig. 6 Climatological mean during boreal summer(May-October) of 1994-2013 (a)OLR of reanalysis, (b)OLR of 9 d lead time prediction, (c)700-1000 hPa specific humidity of reanalysis, (d)700-1000 hPa specific humidity of 9 d lead time prediction
图 7 1994—2013年夏季(5—10月)10~30 d OLR(填色)和850 hPa涡度(等值线,单位:10-6 s-1,由0.5×10-6 s-1起始,每条线间隔为0.5×10-6 s-1)与MV-EOF第4模态对应时间系数超前回归
(黄色框为同期对流西北侧涡度最大值中心)
Fig. 7 Lead regression coefficients of 10-30 d filtered OLR(the shaded, unit:W·m-2) and 850 hPa vorticity(the contour, unit:10-6 s-1, starting from 0.5×10-6 s-1 with an interval of 0.5×10-6 s-1) to time series of the fourth mode(the yellow box marks the positive vorticity center to the northwest of convection of lag 0 d) during boreal summer(May-Oct) of 1994-2013
图 9 1994—2013年夏季(5—10月)10~30 d 850 hPa的涡度方程收支项(等值线,单位:10-12 s-2)和OLR(填色)与MV-EOF第4模态对应时间系数的同期回归
Fig. 9 Regression coefficients of 10-30 d filtered 850 hPa vorticity equation budget terms (the contour, unit:10-12 s-2) and OLR(the shaded) to time series of the fourth mode during boread summer(May-Oct) of 1994-2013
-
[1] Madden R A, Julian P R.Detection of a 40-50 day oscillation in the zonal wind in the tropical Pacific.J Atmos Sci, 1971, 28(5):702-708. doi: 10.1175/1520-0469(1971)028<0702:DOADOI>2.0.CO;2 [2] Madden R A, Julian P R.Description of global-scale circulation cells in the tropics with a 40-50 day period.J Atmos Sci, 1972, 29(6):1109-1123. doi: 10.1175/1520-0469(1972)029<1109:DOGSCC>2.0.CO;2 [3] Yasunari T.A quasi-stationary appearance of 30 to 40 day period in the cloudiness fluctuation during the summer monsoon over India.J Meteor Soc Japan, 1980, 58(3):225-229. doi: 10.2151/jmsj1965.58.3_225 [4] 任宏利, 吴捷, 赵崇博, 等.MJO预报研究进展.应用气象学报, 2015, 26(6):658-668. doi: 10.11898/1001-7313.20150602 [5] Chen T C, Chen J M.The 10-20-day mode of the 1979 Indian monsoon:Its relation with the time variation of monsoon rainfall.Mon Wea Rev, 1993, 121(9):2465-2482. doi: 10.1175/1520-0493(1993)121<2465:TDMOTI>2.0.CO;2 [6] Zhang C D.The Madden-Julian Oscillation.RevGeophys, 2005, 43(2):RG2003. http://cn.bing.com/academic/profile?id=2c42b15104fc377d14e716ee00220433&encoded=0&v=paper_preview&mkt=zh-cn [7] 李崇银, 凌健, 宋洁, 等.中国热带大气季节内振荡研究进展.气象学报, 2014, 72(5):817-834. doi: 10.11676/qxxb2014.059 [8] Vitart F, Ardilouze C, Bonet A, et al.The sub-seasonal to seasonal prediction (S2S) project database.Bull Amer Meteor Soc, 2017, 98(1):163-173. doi: 10.1175/BAMS-D-16-0017.1 [9] 李崇银.大气中的季节内振荡.大气科学, 1990, 14(1):32-45. http://www.cnki.com.cn/Article/CJFDTOTAL-ZKJZ200407004.htm [10] 林爱兰, Li Tim, 李春晖.热带夏季风场与对流场季节内振荡传播模比较.应用气象学报, 2010, 21(5):545-557. doi: 10.11898/1001-7313.20100504 [11] Lee J Y, Wang B, Wheeler M C, et al.Real-time multivariate indices for the boreal summer intraseasonal oscillation over the Asian summer monsoon region.Clim Dyn, 2013, 40(1-2):493-509. doi: 10.1007/s00382-012-1544-4 [12] Webster P J.Monsoon:Processes, predictability and the prospects for prediction.J Geophys Res, 1998, 103(C7):14451-14510. doi: 10.1029/97JC02719 [13] Annamalai H, Slingo J M.Active/break cycles:Diagnosis of the intraseasonal variability of the Asian summer monsoon.Clim Dyn, 2001, 18(1-2):85-102. doi: 10.1007/s003820100161 [14] 陈官军, 魏凤英, 姚文清, 等.基于南海夏季风季节内振荡的降水延伸预报试验.应用气象学报, 2016, 27(3):273-284. doi: 10.11898/1001-7313.20160302 [15] 王遵娅, 丁一汇.夏季长江中下游旱涝年季节内振荡气候特征.应用气象学报, 2008, 19(6):710-715. doi: 10.11898/1001-7313.20080610 [16] 林爱兰, 李春晖, 郑彬, 等.6月MJO对广东降水调制与直接影响系统的联系.应用气象学报, 2013, 24(4):397-406. doi: 10.11898/1001-7313.20130402 [17] Hsu P C, Lee J Y, Ha K J.Influence of boreal summer intraseasonal oscillation on rainfall extremes in southern China.Int J Climatol, 2016, 36(3):1403-1412. doi: 10.1002/joc.2016.36.issue-3 [18] Hsu P C, Lee J Y, Ha K J, et al.Influences of boreal summer intraseasonal oscillation on heat waves in monsoon Asia.J Climate, 2017, 30(18):7191-7211. doi: 10.1175/JCLI-D-16-0505.1 [19] 温敏, 张人禾.苏门答腊附近大气准双周振荡的可能维持机制.科学通报, 2005, 50(9):938-940. http://www.oalib.com/paper/1681857 [20] Chen G H, Sui C H.Characteristics and origin of quasi-biweekly oscillation over the western North Pacific during boreal summer.J Geophys Res, 2010, 115(D14113):1-14. http://cn.bing.com/academic/profile?id=4b8e4dad1ca758d00c8bca2d1903a7fb&encoded=0&v=paper_preview&mkt=zh-cn [21] 李春晖, 何超, 郑彬, 等.夏季(5-10月)南海准双周和20~60天振荡的年代际变化特征.热带气象学报, 2016, 32(5):577-587. http://www.cnki.com.cn/Article/CJFDTotal-DQXK405.005.htm [22] 孙长, 毛江玉, 吴国雄.大气季节内振荡对夏季西北太平洋热带气旋群发性的影响.大气科学, 2009, 33(5):950-958. http://www.cnki.com.cn/Article/CJFDTOTAL-DQXK200905008.htm [23] Zhao H K, Jiang X A, Wu L G.Modulation of Northwest Pacific tropical cyclone genesis by the intraseasonal variability.J Meteor Soc Japan, 2015, 93(1):81-97. doi: 10.2151/jmsj.2015-006 [24] 李春晖, 刘燕, 李霞, 等.热带西北太平洋10~30 d振荡对南海夏季风影响.应用气象学报, 2016, 27(3):293-302. doi: 10.11898/1001-7313.20160304 [25] 占瑞芬, 孙国武, 赵兵科, 等.中国东部副热带夏季风降水的准双周振荡及其可能维持机制.高原气象, 2008, 7(增刊I):98-108. http://www.cqvip.com/QK/91655X/2008B12/30744362.html [26] Liu X W, Wu T W, Yang S, et al.Performance of the seasonal forecasting of the Asian-western Pacific summer monsoon hindcasted by BCC_CSM1.1(m).Adv Atmos Sci, 2015, 32(8):1156-1172. doi: 10.1007/s00376-015-4194-8 [27] 苗芮, 温敏, 张人禾.2010年华南前汛期持续性降水异常与准双周振荡.热带气象学报, 2017, 33(2):155-166. https://www.cnki.com.cn/lunwen-1016121549.nh.html [28] Kemball-Cook S, Wang B.Equatorial waves and air-sea interaction in the boreal summer intraseasonal oscillation.J Climate, 2001, 14(13):2923-2942. doi: 10.1175/1520-0442(2001)014<2923:EWAASI>2.0.CO;2 [29] Jiang X A, Li T, Wang B.Structures and mechanisms of the northward propagating boreal summer intraseasonal oscillation.J Climate, 2004, 17(5):1022-1039. doi: 10.1175/1520-0442(2004)017<1022:SAMOTN>2.0.CO;2 [30] Bellon G, Sobel A H.Instability of the axisymmetric monsoon flow and intraseasonal oscillation.J Geophys Res, 2008, 113(D07108):1-18. http://cn.bing.com/academic/profile?id=e6352737074b2691e30f63c415e8967c&encoded=0&v=paper_preview&mkt=zh-cn [31] Wang B, Xie X.A model for the boreal summer intra-seasonal oscillation.J Atmos Sci, 1997, 54(1):72-86. doi: 10.1175/1520-0469(1997)054<0072:AMFTBS>2.0.CO;2 [32] Hsu H H, Weng C H.Northwestward propagation of the intra-seasonal oscillation in the western North Pacific during the boreal summer:Structure and mechanism.J Climate, 2001, 14(18):3834-3850. doi: 10.1175/1520-0442(2001)014<3834:NPOTIO>2.0.CO;2 [33] Tsou C H, Hsu P C, Kau W S, et al.Northward and northwestward propagation of 30-60 day oscillation in the tropical and extra-tropical western North Pacific.J Meteor Soc Japan, 2005, 83(5):711-726. doi: 10.2151/jmsj.83.711 [34] Waliser D E.Predictability of Tropical Intraseasonal Variability.Cambridge:Cambridge University Press, 2006:275-305. doi: 10.1007/s13143-010-0013-4 [35] 丁一汇, 梁萍.基于MJO的延伸预报.气象, 2010, 36(7):111-122. doi: 10.7519/j.issn.1000-0526.2010.07.018 [36] 吴统文, 宋连春, 刘向文, 等.国家气候中心短期气候预测模式系统业务化进展.应用气象学报, 2013, 24(5):533-543. doi: 10.11898/1001-7313.20130503 [37] Lin J L, Lee M I, Kim D, et al.The impacts of convective parameterization and moisture triggering on AGCM-simulated convectively coupled equatorial waves.J Climate, 2008, 21(5):883-909. doi: 10.1175/2007JCLI1790.1 [38] Seo K H, Wang W Q, Gottschalck J, et al.Evaluation of MJO forecast skill from several statistical and dynamical forecast models.J Climate, 2009, 22(9):2372-2388. doi: 10.1175/2008JCLI2421.1 [39] Kang I S, Kim H M.Assessment of MJO predictability for boreal winter with various statistical and dynamical models.J Climate, 2010, 23(9):2368-2378. [40] Fu X H, Lee J Y, Wang B, et al.Intraseasonal forecasting of Asian summer monsoon in four operational and research models.J Climate, 2013, 26(12):4186-4203. doi: 10.1175/JCLI-D-12-00252.1 [41] Lee S S, Wang B, Waliser D E, et al. Predictability and prediction skill of the boreal summer intraseasonal oscillation in the Intraseasonal Variability Hindcast Experiment.Clim Dyn, 2015, 45(7-8):2123-2135. doi: 10.1007/s00382-014-2461-5 [42] Zhao C, Zhou T J, Song L C, et al. The boreal summer intraseasonal oscillation simulated by four Chinese AGCMs participating in the CMIP5 project.Adv Atmos Sci, 2014, 31(5):1167-1180. doi: 10.1007/s00376-014-3211-7 [43] 吴捷, 任宏利, 赵崇博, 等.国家气候中心MJO监测预测业务产品研发及应用.应用气象学报, 2016, 27(6):641-653. doi: 10.11898/1001-7313.20160601 [44] Fang Y J, Wu P L, Wu T W, et al.An evaluation of boreal summer intra-seasonal oscillation simulated by BCC_AGCM2.2.Clim Dyn, 2016, 48(9-10):3409-3423. http://cn.bing.com/academic/profile?id=00ccb81b98943e86ba6b7611a5d76880&encoded=0&v=paper_preview&mkt=zh-cn [45] Liu X W, Wu T W, Yang S, et al.MJO prediction using the sub-seasonal to seasonal forecast model of Beijing Climate Center.Clim Dyn, 2016, 48(9-10):3283-3307. http://cn.bing.com/academic/profile?id=4d132df5a6bddf341083744618c3922a&encoded=0&v=paper_preview&mkt=zh-cn [46] Liebmann B, Smith C A.Description of a complete (interpolated) outgoing longwave radiation dataset.Bull Amer Meteor Soc, 1996, 77(6):1275-1277. http://cn.bing.com/academic/profile?id=f45876087ea92ee7472ee8765a838604&encoded=0&v=paper_preview&mkt=zh-cn [47] Dee D P, Uppala S M, Simmons A J, et al.The ERA-Interim reanalysis:Configuration and performance of the data assimilation system.Quart J Roy Meteor Soc, 2011, 137(656):553-597. doi: 10.1002/qj.v137.656 [48] Kalnay E, Kanamitsu M, Kistler R, et al.The NCEP/NCAR 40-year reanalysis project.Bull Amer Meteor Soc, 1996, 77(3):437-471. doi: 10.1175/1520-0477(1996)077<0437:TNYRP>2.0.CO;2 [49] Wheeler M, Hendon H.An all-season real-time multivariate MJO index:Development of an index for monitoring and prediction.Mon Wea Rev, 2004, 132(8):1917-1932. doi: 10.1175/1520-0493(2004)132<1917:AARMMI>2.0.CO;2 [50] Lin H, Brunet G, Derome J.Forecast skill of the Madden-Julian oscillation in two Canadian atmospheric models.Mon Wea Rev, 2008, 136(11):4130-4149. doi: 10.1175/2008MWR2459.1 [51] Xiang B Q, Zhao M, Jiang X A, et al.The 3-4-Week MJO prediction skill in a GFDL coupled model.J Climate, 2015, 28(13):5351-5364. doi: 10.1175/JCLI-D-15-0102.1 [52] Honton J R.An Introduction to Dynamic Meteorology.New York:Academic Press, 1979.