摘要
采用1979-2012年ERA-interim再分析资料和地面降水同化资料,利用青藏高原(下称高原)地区风场的变化特征,定义了一个新的基于风场标准化季节变率的高原季风指数IPMzhang,并与现有的季风指数IPMtang、IPMqi和IPMxun进行了比较分析。结果表明:各个指数都能够反映高原地区的季风活动特征及其与高原及周边地区夏季降水的相关关系,IPMqi和IPMzhang指数在高分辨率数据下的表现优于IPMtang和IPMxun指数,显著相关区域覆盖了高原大部分地区。相较于IPMqi,IPMzhang指数的相关系数略低,但其在高原东南部地区更为显著,表明IPMzhang能够更好地反映高原东南部地区的夏季降水。受高原热低压强度变化的影响,在季风偏强年IPMtang和IPMxun的异常水汽辐合主要在高原中部,IPMqi则存在于高原各个地区,只有IPMzhang在高原东南部,有利于高原东南部的降水偏多。表明IPMzhang指数能够较好地表征高原季风与高原及周边地区夏季降水的相关关系,对于高原地区降水,尤其是高原东南部人口相对密集地区的降水预测具有较好的指示意义。
By using the reanalysis data of ERA-interim and assimilated data of precipitation in the period of 1979 to 2012,a newplateau monsoon index,named IPMzhang,was defined,based on the wind dynamical normalized seasonality index. After compared with existing monsoon indices,IPMtang,IPMqiand IPMxun,the following conclusions were given. Each index could well reflect the activity of the plateau monsoon and its relationship with precipitation on the Qinghai-Xizang Plateau( QXP) and its surrounding areas. When compared with IPMtangand IPMxun,IPMqiand IPMzhangshowed better relationships with precipitation at a more broad significant area on the QXP under high resolution data. The correlation coefficients of IPMzhangwere a little smaller than that of IPMqi,but IPMzhangshowed bigger correlation coefficients in the southeast part of the QXP,meaning that IPMzhangcould well reflect the summer precipitation there. Composite analysis also showed that abnormal water vapor convergence was found in the years monsoon was strong. It mainly distributed at the central part of the QXP in IPMtang and IPMxun,over almost all of the QXP in IPMqi,and over the southeast part of the QXP in IPMzhang. It was IPMzhangthat showed a more proper distribution of the abnormal water vapor convergence on the QXP,leading to a better correlation with the summer precipitation of southeast QXP. In a word,the newdefined monsoon index on the QXP could well reflect the summer precipitation on the QXP,especially for the southeast part of the QXP where more people live.
出处
《高原气象》
CSCD
北大核心
2015年第4期881-889,共9页
Plateau Meteorology
基金
国家自然科学基金重点项目(41130961)
国家自然科学基金项目(41375015
41405015
91437102)
关键词
高原季风
季风指数
降水
标准化季节变率
Plateau monsoon
Monsoon index
Precipitation
Dynamical normalized seasonality
