Experiments on Simulation of Typhoon Soudelor with GRAPES Hybrid-3DVar System
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摘要: 为了把反映天气形势变化的背景误差协方差引入到变分分析系统中来提高分析质量,本文在GRAPES区域三维变分框架的基础上通过扩展控制变量方法实现动态与静态背景误差协方差耦合,建立混合三维变分分析系统(GRAPES Hybrid-3DVar)。通过控制变量扰动产生的集合样本进行单点观测分析试验验证Hybrid-3DVar及其局地化方案的合理性,并针对台风苏迪罗进行实际观测资料同化和数值预报试验,结果表明:用集合样本描述的背景误差协方差是随着天气流型变化的,动力场和质量场的离散度在台风中心处最大,因而混合同化的分析增量包含更多细微结构和中小尺度信息;其分析和24 h内预报要素质量优于3DVar,24 h内降水强度和落区预报也更准确,混合同化分析改善了3DVar分析的降水空报问题;同时混合同化分析的24 h内台风路径预报也最接近实况,台风强度预报在48 h之内都比3DVar更接近观测。
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关键词:
- Hybrid-3DVar /
- 3DVar /
- GRAPES /
- 局地化 /
- 台风苏迪罗
Abstract: To improve the analysis quality by incorporating the flow-dependent ensemble covariance into the variational data assimilation system, the new GRAPES (global/regional assimilation and prediction system) hybrid-3Dvar system was built. The new system is based on the GRAPES regional 3DVar system, which uses the statistic covariance, and was built by augmenting the state vectors with another set of control variables preconditioned upon the ensemble dynamic covariance. The new hybrid-3DVar system and the localization method were verified through a single-observation assimilation experiment with ensemble samples produced by the 3D-Var’s control variable perturbation method. The real observation assimilation and forecast experiment for Typhoon Soudelor yielded the following conclusions: (1) The background covariance, which is represented by ensemble samples, is flow-dependent, and the root mean square spread in the ensemble of momentum field and mass field is largest near the typhoon center. (2) The analysis increments of the new hybrid-3DVar have a more detailed structure and more medium- and small-scale information. (3) The analysis and 24 h prediction qualities of model variables in the new hybrid-3DVar are significantly improved compared with the 3DVar system, and the precipitation position predictions are more accurate. (4) The 24 h forecast track of Typhoon Soudelor is closer to the observational one, and the 48 h-predicted intensity also approaches the real observation.-
Key words:
- Hybrid-3DVar /
- 3DVar /
- GRAPES /
- Localization /
- Typhoon Soudelor
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图 1 三组理想实验单点气压观测的无量纲气压(PI;左列)、纬向风场分量(U,单位:m s‒1;中间列)、经向风场分量(V,单位:m s‒1;右列)的水平分析增量:(a1–a3)三维变分试验(3DVar);(b1–b3)背景误差采用全动态的混合分析试验(Hybrid_NoVertloc);(c1–c3)采用垂直相关的局地化方案的混合分析试验(Hybrid_Vertloc)
Figure 1. Non-dimensional pressure (PI; left column), U-component (U, units: m s‒1, middle column), V-component (V, units: m s‒1, right column) of horizontal analysis increments with one pressure observation of three ideal experiments: (a1–a3)3DVar; (b1–b3) full hybrid without vertical localization; (c1–c3)hybrid with vertical localization
图 5 观察点A(黑点所示)与其他格点在剖面26°N处的(a)PI、(b)Q(单位:kg kg‒1)、(c)U(单位:m s‒1)和(d)V(单位:m s‒1)的离散度(廓线)以及垂直相关系数(填色)的垂直分布
Figure 5. Vertical correlation (shaded) and ensemble spread (contours) with respect to point A (black dot) at 26°N section for (a) PI, (b) Q (units: kg kg‒1), (c) U (units: m s‒1), and (d) V (units: m s‒1)
图 6 3DVar试验第10层模式面的分析增量分布:(a)PI;(b)Q(单位:kg kg‒1);(c)U(单位:m s‒1);(d)V(单位:m s‒1)。图中黑点为台风中心位置,矢量箭头为背景风场。
Figure 6. Horizontal analysis increments of 3DVar on level 10: (a) PI, (b) Q (units: kg kg‒1), (c) U (units: m s‒1), and (d) V (units: m s‒1). Black dot is location of super typhoon Soudelor, vector arrow is background wind field
图 8 925 hPa 3DVar与Hybrid分析的绝对误差差别(填色)(a)PI;(b)Q(单位:kg kg‒1);(c)U(单位:m s‒1);(d)V(单位:m s‒1)。图中黑点为台风中心位置, 矢量箭头为背景风场
Figure 8. Differences in absolute errors between the analysis of 3DVar and hybrid (shaded) (a) PI, (b) Q (units: kg kg‒1), (c) U (units: m s‒1), and (d) V (units: m s‒1). Black dot is location of super typhoon Soudelor, vector arrow is background wind field
图 13 2015年8月(a‒c)8日12:00~18:00和(d‒f)8日18:00至9日00:00的累积降水量(单位:mm)分布:(a、d)实况观测;(b、e)3DVar预报结果;(c、f)Hybrid预报结果
Figure 13. The distribution of accumulated precipitation (a‒c) f from 1200 UTC to 1800 UTC 8 August and (d‒f) from 1800 UTC 8 to 0000 UTC 9 August, 2015: (a, d) Observation; (b, e) 3DVar forecast; (c, f) hybrid forecast
图 14 2015年8月9日(a‒c)00:00~06:00和(d‒f)9日06:00~12:00的累积降水量(单位:mm)分布:(a、d)实况观测;(b、e)3DVar预报结果;(c、f)Hybrid预报结果
Figure 14. The distribution of accumulated precipitation (a‒c) from 0000 UTC to 0600 UTC and (d‒f) from 0600 UTC to 1200 UTC 9 August, 2015: (a, d) Observation; (b, e) 3DVar forecast; (c, f) hybrid forecast
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[1] Buehner M, Houtekamer P L, Charette C, et al. 2010a. Intercomparison of variational data assimilation and the ensemble Kalman filter for global deterministic NWP. Part I: Description and single-observation experiments [J]. Mon. Wea. Rev., 138(5): 1550−1566. doi: 10.1175/2009MWR3157.1 [2] Buehner M, Houtekamer P L, Charette C, et al. 2010b. Intercomparison of variational data assimilation and the ensemble Kalman filter for global deterministic NWP. Part II: One–month experiments with real observations [J]. Mon. Wea. Rev., 138(5): 1567−1586. doi: 10.1175/2009MWR3158.1 [3] Chen Lianglü, Chen Jing, Xue Jishan, et al. 2015. Development and testing of the GRAPES regional ensemble–3DVAR hybrid data assimilation system [J]. J. Meteor. Res., 29(6): 981−996. doi: 10.1007/s13351-015-5021-y [4] Denis B, Côté J, Laprise R. 2002. Spectral decomposition of two-dimensional atmospheric fields on limited-area domains using the Discrete Cosine Transform (DCT) [J]. Mon. Wea. Rev., 130(7): 1812−1829. doi:10.1175/1520-0493(2002)130<1812:SDOTDA>2.0.CO;2 [5] Gao Jidong, Stensrud D J. 2014. Some observing system simulation experiments with a hybrid 3DEnVAR system for storm–scale Radar data assimilation [J]. Mon. Wea. Rev., 142(9): 3326−3346. doi: 10.1175/MWR-D-14-00025.1 [6] Hamill T M, Snyder C. 2000. A hybrid ensemble Kalman filter-3D variational analysis scheme [J]. Mon. Wea. Rev., 128(8): 2905−2919. doi:10.1175/1520-0493(2000)128<2905:AHEKFV>2.0.CO;2 [7] Hamill T M, Whitaker J S. 2001. Distance-dependent filtering of background error covariance estimates in an ensemble kalman filter [J]. Mon. Wea. Rev., 129(11): 2776−2790. doi:10.1175/1520-0493(2001)129<2776:DDFOBE>2.0.CO;2 [8] 何光鑫, 李刚, 张华. 2011. GRAPES-3DVar高阶递归滤波方案及其初步试验 [J]. 气象学报, 69(6): 1001−1008. doi: 10.11676/qxxb2011.087He Guangxin, Li Gang, Zhang Hua. 2011. The scheme of high-order recursive filter for the GRAPES 3DVar with its initial experiments [J]. Acta Meteorologica Sinica (in Chinese), 69(6): 1001−1008. doi: 10.11676/qxxb2011.087 [9] Houtekamer P L, Mitchell H L. 1998. Data assimilation using an ensemble Kalman filter technique [J]. Mon. Wea. Rev., 126(3): 796−811. doi:10.1175/1520-0493(1998)126<0796:DAUAEK>2.0.CO;2 [10] Houtekamer P L, Mitchell H L. 2001. A sequential ensemble Kalman filter for atmospheric data assimilation [J]. Mon. Wea. Rev., 129(1): 123−137. doi:10.1175/1520-0493(2001)129<0123:ASEKFF>2.0.CO;2 [11] Houtekamer P L, Mitchell H L, Pellerin G, et al. 2005. Atmospheric data assimilation with an ensemble Kalman Filter: Results with real observations [J]. Mon. Wea. Rev., 133(3): 604−620. doi: 10.1175/MWR-2864.1 [12] 兰伟仁, 朱江, Xue Ming, et al. 2010. 风暴尺度天气下利用集合卡尔曼滤波模拟多普勒雷达资料同化试验II. 考虑模式误差的情形 [J]. 大气科学, 34(4): 737−753. doi: 10.3878/j.issn.1006-9895.2010.04.07Lan Weiren, Zhu Jiang, Xue Ming, et al. 2010. Storm–scale ensemble Kalman filter data assimilation experiments using simulated Doppler radar data part II: Imperfect model tests [J]. Chinese Journal of Atmospheric Sciences (in Chinese), 34(4): 737−753. doi: 10.3878/j.issn.1006-9895.2010.04.07 [13] Liu Chengsi, Xiao Qingnong, Wang Bin. 2008. An Ensemble-based four-dimensional variational data assimilation scheme. Part I: Technical formulation and preliminary test [J]. Mon. Wea. Rev., 136(9): 3363−3373. doi: 10.1175/2008MWR2312.1 [14] Liu Chengsi, Xiao Qingnong, Wang Bin. 2009. An Ensemble-based four-dimensional variational data assimilation scheme. Part II: Observing system simulation experiments with Advanced Research WRF (ARW) [J]. Mon. Wea. Rev., 137(5): 1687−1704. doi: 10.1175/2008MWR2699.1 [15] Lu Huijuan, Xu Qin. 2009. Trade-offs between measurement accuracy and resolutions in configuring phased-array radar velocity scans for ensemble-based storm–scale data assimilation [J]. J. Appl. Meteor. Climatol., 48(6): 1230−1244. doi: 10.1175/2008JAMC2009.1 [16] 马旭林, 陆续, 于月明, 等. 2014. 数值天气预报中集合-变分混合资料同化及其研究进展 [J]. 热带气象学报, 30(6): 1188−1195. doi: 10.3969/j.issn.1004-4965.2014.06.020Ma Xulin, Lu Xu, Yu Yueming, et al. 2014. Progress on hybrid ensemble-variational data assimilation in numerical weather prediction [J]. Journal of Tropical Meteorology (in Chinese), 30(6): 1188−1195. doi: 10.3969/j.issn.1004-4965.2014.06.020 [17] 马旭林, 李琳琳, 周勃旸, 等. 2015. 台风预报误差的流依赖特征及混合资料同化中最优耦合系数 [J]. 大气科学学报, 38(6): 766−775. doi: 10.13878/j.cnki.dqkxxb.20141224001Ma Xulin, Li Linlin, Zhou Boyang, et al. 2015. Flow-dependent characteristics of typhoon forecasting errors and optimal coupling coefficient in hybrid data assimilation [J]. Trans. Atmos. Sci. (in Chinese), 38(6): 766−775. doi: 10.13878/j.cnki.dqkxxb.20141224001 [18] 邱晓滨, 邱崇践. 2009. 混合误差协方差用于集合平方根滤波同化的试验 [J]. 高原气象, 28(6): 1399−1407.Qiu Xiaobin, Qiu Chongjian. 2009. The suitability test of ensemble square root filter with hybrid background error covariance [J]. Plateau Meteorology (in Chinese), 28(6): 1399−1407. [19] Snyder C, Zhang Fuqing. 2003. Assimilation of simulated Doppler radar observations with an ensemble Kalman filter [J]. Mon. Wea. Rev., 131(8): 1663−1677. doi: 10.1175//2555.1 [20] Vandenberghe F, Kuo Y H. 1999. Introduction to the MM5 3D-VAR data assimilation system: Theoretical basis [R]. NCAR Technical note 917: 1–38. [21] Wang Xuguang, Snyder C, Hamill T M. 2007a. On the theoretical equivalence of differently proposed ensemble-3DVAR hybrid analysis schemes [J]. Mon. Wea. Rev., 135(1): 222−227. doi: 10.1175/MWR3282.1 [22] Wang Xuguang, Hamill T M, Whitaker J S, et al. 2007b. A comparison of hybrid ensemble transform kalman filter–optimum interpolation and ensemble square root filter analysis schemes [J]. Mon. Wea. Rev., 135(3): 1055−1076. doi: 10.1175/MWR3307.1 [23] Wang Xuguang, Barker D M, Snyder C, et al. 2008a. A hybrid ETKF-3DVar data assimilation scheme for the WRF model. Part I: Observing system simulation experiment [J]. Mon. Wea. Rev., 136(12): 5116−5131. doi: 10.1175/2008MWR2444.1 [24] Wang Xuguang, Barker D M, Snyder C, et al. 2008b. A hybrid ETKF-3DVar data assimilation scheme for the WRF model. Part II: Real observation experiments [J]. Mon. Wea. Rev., 136(12): 5132−5147. doi: 10.1175/2008MWR2445.1 [25] 吴洋, 徐枝芳, 王瑞春, 等. 2018. 基于多尺度混合滤波的GRAPES_3Dvar及其在实际暴雨预报中的应用分析 [J]. 气象, 44(5): 621−633. doi: 10.7519/j.issn.1000-0526.2018.05.003Wu Yang, Xu Zhifang, Wang Ruichun, et al. 2018. Improvement of GRAPES_3Dvar with a new multi–scale filtering and its application in heavy rain forecasting [J]. Meteorological Monthly (in Chinese), 44(5): 621−633. doi: 10.7519/j.issn.1000-0526.2018.05.003 [26] 薛纪善, 刘艳, 张林, 等. 2012. GRAPES全球三维变分同化系统模式变量分析版科学文档 [R]. 中国气象局数值预报中心内部技术手册, 1–30.Xue Jishan, Liu Yan, Zhang Lin, et al. 2012. Scientific documentation of GRAPES-3DVar version for global model [R]. Numerical Weather Prediction Center, China Meteorological Administration (in Chinese), 1–30. [27] Zhang Meng, Zhang Fuqing. 2012. E4DVar: Coupling an ensemble Kalman filter with four-dimensional variational data assimilation in a limited-area weather prediction model [J]. Mon. Wea. Rev., 140(2): 587−600. doi: 10.1175/MWR-D-11-00023.1 [28] Zhang F, Snyder C, Sun Juanzhen. 2004. Impacts of initial estimate and observation availability on convective-scale data assimilation with an ensemble Kalman Filter [J]. Mon. Wea. Rev., 132(5): 1238−1253. doi:10.1175/1520-0493(2004)132<1238:IOIEAO>2.0.CO;2 [29] 郑永骏, 金之雁, 陈德辉. 2008. 半隐式半拉格朗日动力框架的动能谱分析 [J]. 气象学报, 66(2): 143−157. doi: 10.11676/qxxb2008.015Zheng Yongjun, Jin Zhiyan, Chen Dehui. 2008. Kinetic energy spectrum analysis in a semi implicit semi Lagrangian dynamical framework [J]. Acta Meteor. Sinica (in Chinese), 66(2): 143−157. doi: 10.11676/qxxb2008.015 [30] 朱琳, 寿绍文, 彭加毅, 等. 2008. 集合卡尔曼滤波同化探空资料的数值试验 [J]. 南京气象学院学报, 31(2): 264−271. doi: 10.3969/j.issn.1674-7097.2008.02.017Zhu Lin, Shou Shaowen, Peng Jiayi, et al. 2008. Numerical test of an ensemble Kalman filter for sounding data assimilation [J]. Journal of Nanjing Institute of Meteorology (in Chinese), 31(2): 264−271. doi: 10.3969/j.issn.1674-7097.2008.02.017 [31] 庄照荣, 薛纪善, 李兴良. 2011a. GRAPES集合卡尔曼滤波资料同化系统I: 系统设计及初步试验 [J]. 气象学报, 69(4): 620−630. doi: 10.11676/qxxb2011.054Zhuang Zhaorong, Xue Jishan, Li Xingliang. 2011a. The GRAPES ensemble Kalman filter data assimilation system. Part I: Design and its tentative experiment [J]. Acta Meteorologica Sinica (in Chinese), 69(4): 620−630. doi: 10.11676/qxxb2011.054 [32] 庄照荣, 薛纪善, 李兴良. 2011b. GRAPES集合卡尔曼滤波资料同化系统II: 区域分析及集合预报 [J]. 气象学报, 69(5): 860−871. doi: 10.11676/qxxb2011.075Zhuang Zhaorong, Xue Jishan, Li Xingliang. 2011b. The GRAPES ensemble Kalman filter data assimilation system. Part II: Regional analysis and ensemble prediction [J]. Acta Meteorologica Sinica (in Chinese), 69(5): 860−871. doi: 10.11676/qxxb2011.075 [33] 庄照荣, 陈静, 黄丽萍, 等. 2018. 全球和区域分析的混合方案对区域预报的影响试验 [J]. 气象, 44(12): 1509−1517. doi: 10.7519/j.issn.1000-0526.2018.12.001Zhuang Zhaorong, Chen Jing, Huang Liping, et al. 2018. Impact experiments for regional forecast using blending method of global and regional analyses [J]. Meteor. Mon. (in Chinese), 44(12): 1509−1517. doi: 10.7519/j.issn.1000-0526.2018.12.001 -