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投稿时间：2016-03-01 修订日期：2016-09-01
投稿时间：2016-03-01 修订日期：2016-09-01
中文摘要: 对不同时效预报的调整趋势进行分析，是预估预报误差和对预报进行订正的一种思路。为了系统性检验这一思路的有效性，本文定义了西风槽强度和位置指数，以及西北太平洋副热带高压(简称副高)强度和位置等指数，运用2011年4月以来的500 hPa位势高度场预报资料，研究对比了ECMWF(简称EC)和T639模式对副高和我国不同区域西风槽的位置和强度，72 h时效内对同一时刻不同时效的预报，随预报时效的临近，预报调整趋势之间的相关性和一致性。研究结果显示，EC和T639模式对副高的预报，都存在西脊点偏东、范围偏小、强度偏弱和北界偏南的系统性偏差，且时效越长偏差越大，T639模式的偏差明显大于EC模式，但相关性分析和方差分析表明，不同时效的调整趋势之间并不存在较为显著的相关性，即不同时效的预报并没有较为明显的、一致的调整趋势。另外，副高的预报误差与西脊点所处的经度有关，从东印度洋到菲律宾以东洋面，西脊点越往东，预报误差和系统偏差越小，但西脊点位于不同的经度区间时，不同时效的调整趋势之间同样没有明显的相关性，且整体上以负的协方差为主。对于西风槽，两家模式北方槽的误差都明显大于南方槽的误差，强度的误差较小，且T639的误差明显大于EC模式，相邻时效的调整趋势之间以负的协方差为主，说明随时效的临近，槽的位置并没有较为一致的调整趋势。同时不同时期预报调整趋势之间的相关性分析显示，模式版本的升级，并没有改变调整趋势之间几乎无一致性的特征。
中文关键词: 数值模式， 预报调整趋势， 一致性
Abstract:Modifying trend (MD) analysis for different forecasts at same valid time is a method to estimate the forecast error and calibrate the forecast. To verify the validation of this method, intensity and position index of the westerly wind trough (WWT) and area index, intensity index, west ridge point and north edge index of the subtropical high (sTH) of northwest Pacific Ocean are defined. Using the 500 hPa geopotential height forecast dataset from April 2011 to September 2015, the correlation and consistency of intensity and position MDs of sTH and WWT at different positions around China produced by ECMWF （EC） and T639 models are analyzed and compared. The results show that there are systematic biases for EC and T639 sTH forecast and the WWTs are nearly bias free. The systematic biases of T639 are larger than that of EC. As the lead times are prolonged, the sTH eastward systematic biases of west ridge points and decreasing intensity and area systematic biases are enlarged. The west ridge point, intensity and area of sTH show no significant correlations among the MDs of different lead times and the MDs are not consistent for EC and T639. The forecast error and MD characteristics of sTH are different as the west ridge points are located at different longitudes. As the west ridge point moves from the east Indian Ocean to the northwest Pacific Ocean east of Philippines Islands, the sTH forecast errores and systematic biases decrease. In different longitude ranges there is no significant correlation among MDs of different lead times and their covariances are negative, which means the MDs are inconsistent. For the WWT, EC and T639 models both show that the errors of WWT in high latitudes are larger than that in low latitudes and the errors of WWT intensity are small. The errors of T639 are significantly larger than that of EC. The covariances among MDs of different lead times are negative too, which means that the WWTs position MDs are not consistent for EC and T639 as well. The correlatons among MDs of different periods are nearly 0, which means that the upgrades of EC and T639 models do not have any effects on the inconsistency of MDs.
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基金项目:公益性行业(气象)科研专项(GYHY201306002)资助
| Author Name | Affiliation |
| DONG Quan | National Meteorological Centre, Beijing 100081 |
| HU Haichuan | National Meteorological Centre, Beijing 100081 |
| DAI Kan | National Meteorological Centre, Beijing 100081 |
引用文本：
董全,胡海川,代刊,2016.数值模式预报调整趋势分析[J].气象,42(12):1483-1497.
DONG Quan,HU Haichuan,DAI Kan,2016.Analysis of Forecast Modifying Trend of the Numerical Model[J].Meteor Mon,42(12):1483-1497.
董全,胡海川,代刊,2016.数值模式预报调整趋势分析[J].气象,42(12):1483-1497.
DONG Quan,HU Haichuan,DAI Kan,2016.Analysis of Forecast Modifying Trend of the Numerical Model[J].Meteor Mon,42(12):1483-1497.