国家气候中心MJO监测预测业务产品研发及应用

Research and Application of Operational MJO Monitoring and Prediction Products in Beijing Climate Center

热带大气低频振荡(MJO)和北半球夏季季节内振荡(BSISO)对全球范围天气气候事件有重要影响,是次季节-季节(S2S)预报最主要的可预报性来源之一。国家气候中心(BCC)基于我国完全自主的T639全球分析场数据、风云三号气象卫星射出长波辐射(OLR)资料以及BCC第2代大气环流模式系统的实时预报,发展了MJO实时监测预测一体化业务技术,建立了ISV/MJO监测预测业务系统(IMPRESS1.0),已投入实时业务运行,在全国气象业务系统得到应用。该文着重介绍该系统提供的MJO和BSISO指数监测预测数据和图形产品,并描述了这些业务产品在2015年对MJO典型个例的实时监测预测应用情况。监测分析和预报检验表明,基于我国自主资料的监测结果能够较为准确地表征MJO和BSISO指数的振荡和演变过程,该系统对MJO和BSISO事件分别至少具备16 d和10 d左右的预报技巧。因此,基于IMPRESS1.0的MJO/BSISO监测预测一体化业务产品可为制作延伸期预报提供重要的参考依据。

Both Madden-Julian oscillation（MJO） and the boreal summer intra-seasonal oscillation（BSISO） have great impacts on the global weather and climate events,which are the most important predictability source of sub-seasonal to seasonal（S2S） prediction.However,the monitoring of MJO/BSISO in China National Climate Center/Beijing Climate Center（NCC/BCC） entirely depends on external data,and the prediction skill of the introduced statistical forecast model is also much lower than dynamic mode,and the practical real-time operation ability has not been established.Therefore,based on CMA（China Meteorological Administration） global analysis data of T639 model,OLR（outgoing long-wave radiation） data of FY-3B satellite and the real-time forecast data of BCC atmospheric general circulation model system（BCCAGCM2.2）,applying the real-time multivariate MJO（RMM） index and BSISO index,BCC develops the MJO real-time monitoring and forecast technology,and establishes the trial ISV（intra-seasonal variability）/MJO prediction system（IMPRESS1.0）.In comparison,monitoring results based on T639 wind analysis and FY-3B OLR data is generally consistent with the operational products from other centers,suggesting the capability of characterizing the oscillation and evolution of MJO/BSISO index accurately.Case study for the typical strong MJO event in March 2015 indicates that the amplitude peak of RMM index based on T639 and FY-3B OLR data is weaker than monitoring results based on NCEP and NOAA OLR data.Further analysis for three variables U850（zonal wind at 850 hPa）,U200（zonal wind at 200 hPa） and OLR show that the convection monitored by FY-3B satellite is more consistent with NOAA＇s result,while the projection amplitude of the U850 based on T639 analysis against MJO mode is slightly weaker than NCEP/NCAR reanalysis data,which leads to weaker RMM index amplitude.The forecast skill verification shows the IMPRESS1.0 is able to provide correct evolution and intensity information of MJO at least 16 days in advance,and the skill of operational forecast in 2015 reach 18 days.The rolling prediction skill could be improved continually as the evolution of MJO event,and the predicted RMM index phase space track is closer to reality.Meanwhile,the verification of hindcasts by using correlation skill（COR）,root mean square error（RMSE） and mean square skill score（MSSS） shows that the IMPRESS1.0 has useful prediction skill for about 12 days for MJO index and 8 days for BSISOl and BSIS02 index,respectively.The case study for BSISO event in July 2015 also shows prediction skill,the reconstructed anomaly circulation and convection against BSISO index clearly demonstrate the dominant mode and northward propagation of BSISO.Therefore,the unified monitoring and forecast productions based on IMPRESS1.0 can provide important references for extended-range prediction,and offer certain help for operation and research.