PDF《湿度因子对适应性观测敏感区》

湿度因子对适应性观测敏感区 估算的影响研究 * 张宇1,

2 陈德辉3 薛纪善1 马旭林2 ZH ANG Yu 1,

2 CH EN Dehui

3 XU E Jishan

1 MA Xulin

2 1.

中国气象科学研究院, 北京,

100081 2. 南京信息工程大学, 南京,

210044 3. 国家气象中心, 北京,

100081 1. Chinese A cademy of Meteorological S ciences, Beij ing 100081, China 2. Nanj ing Univ ersity of Inf ormation S cience and Technology , N anj ing 210044, China 3. National Meteorological Centre , Beij ing 100081, China

2010 -01 -27 收稿,

2011 -01 -05 改回. Zhang Yu, Chen Dehui, Xue Jishan, Ma Xulin. 2012. Study of the influence of the humidity factor on estimation in the adaptive observation sensitive region. Acta Meteorologica Sinica, 70( 1) :91-100 Abstract T he ET KF ( Ensemble T ransform Kalman Filter)- DRY adaptive observation scheme can obtain the relative accurate sensitive region, but it hasn. t cont ained the humidity factor. T his article is based on the ETKF -DRY scheme developed by Ma ( 2008) . According to t he difference of the data and the metrics w e constructed three different schemes, and compared w ith the old one. We choose the freezing disaster occurred in the early

2008 as an example. The results show t hat the sensitive area which is calculated by the old one is more scattered, and there are false sensitive areas w hen the verif ication time is equal to the adaptive observation t ime;

w ith the adding of the humidity factor and the changing of the met rics the false sensitive areas have an apparent decrease;

the ETKF -WET-E6 system w hich only contains the humidity factor has the best result s, say, the sens- i t ive areas are more concentrated at t he adaptive observation time and there are no false sensitive areas w hen the verification t ime is equal to the adaptive observation time. Key words Adaptive observation, H umidity factor, Sensitive region, Freezing rain disaster 摘要马旭林

2008 年的基于集合卡尔曼变换适应性观测敏感区的估算方案能得到较为合理的敏感区, 但其未考虑湿度因 子的影响.在原方案基础上增加了湿度因子, 根据计算资料与度量标准的不同, 搭建

3 个方案与其比较, 并选用

2008 年年初 冰冻雨雪灾害天气个例进行对比模拟试验.结果表明, 原方案的敏感区较为分散, 且当目标时刻与验证时刻重合时, 存在虚 假的信号方差大值区;

加入湿度因子后能有效抑制虚假敏感区, 改进度量标准后能得到较为理想的结果;

若只利用湿度场进 行敏感区估算, 计算效果最优, 在目标观测时刻所得敏感区最为集中并在目标时刻和验证时刻重合时无虚假信号方差大值 区. 关键词 适应性观测, 湿度因子, 敏感区, 冰冻雨雪灾害 中图法分类号 P426.

1 0577 -6619/ 2012/ 70( 1)-0091 -00 A cta Meteorologica S inica 气象学报 * 资助课题: 国家公益性行业( 气象) 科研专项项目( GYH Y201006016) 、 国家自然科学基金项目(

41105068、 40805045) . 作者简介: 张宇, 从事数值预报研究.E -m ail:g rapeszy@ gmail. com 通信作者: 陈德辉, 主要从事数值预报研究.E -m ail: chendh@ cma. gov. cn

1 引言数值天气预报在本质上是一个初边值问题, 模 式初值能否准确地描述大气运动状态将决定着数值 预报的成败.近年来, 科学家针对预报误差增长及 其传播特征和可预报性问题的深入研究发现, 高影 响天气系统的上游通常存在相应的观测敏感区, 在 理论上, 如在该敏感区域加强观测改善模式的初值, 能够提高数值预报的质量.据此, 多位学者( Rab- i er, et al, 1996;