南方涛动指数的计算说明
南方涛动指数的计算说明(中英文对照)
计算南方涛动指数(SOI所使用的气候基础数据分为1887-1989以及1933 T992两种，对应着两种不同的计算方法。
1、Troup的计算方法:
SOI=10 x [PA塔希提岛)-PA达尔文)]/气压差异标准差
* Note
PA (Tahiti) - FA (Detrain)〔°
加.加.砌*
其中:PA()=S力异常二每月平均值-长期(1887-1989)平均值气压差异的标准差二基期(1887-1989)的气压差异标准差。(应该指达
尔文和塔希提两地的气压差异标准差)
screening>www cdzk orgTroup的SOI值为-10意味着该月SOI的偏差为长期气压差异标准差的负1倍。Troup从1876年起计算的月度SOI推导自正常化塔希提岛- 达尔文平均海平面压力(mslp)。
2、NCC的计算方法：
国家气候中心(NCC基于Troup的公式对SOI的方法进行了修改,
其基期为1933 -1992年的SOI计算公式为：
SOI=10 x [PA塔希提岛)-PA达尔文)]/气压差异标准差
其中:PA()=S力异常二每月平均值-长期(1933 - 1992)平均值
气压差异标准差二基期(1933-1992)的气压差异标准差。
根据推算，1887-1989年的气压差异标准差(St.Dev.Diff)值约为
感觉英文1.57，塔希提的长期平均大气压减去达尔文的长期平均大气压值约为
2.88，通过这两个参数以及达尔文和塔希提两地的实际大气压即可算出此时的SOI!
SOI可反映厄尔尼诺现象的活跃程度，当南方涛动指数出现持续性的负值，该年有厄尔尼诺现象。相反地，如果南方涛动指数出现持续性的正值，该年有反厄尔尼诺现象也就是拉尼娜现象。
The Southern Oscillation Index (SOI) ud by this site is calculated using a climatic ba period of 1887 to 1989. The Natio nal Climate Ce ntre (NCC) has made a n umber of cha nges to the way the SOI is calculated, in particular cha nging the climatic ba period to 1933-1992. Long Paddock will continue to provide the orig inal SOI data (1887 to 1989 ba period) as the SOI pha maps on Long Paddock are bad on this data.
The file called 'Mon thlySOIPha1887-1989Ba' con tai ns a colum n of numbers un der the head ing 'Pha'. The five Phas of the SOI are as follows:布莱恩 克兰斯顿
1.consistently negative
2.con siste ntly positive
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3.rapidly falli ng
4.rapidly risi ng
5.con siste ntly n ear zero
Troup's SOI Calculati on (ud on this site)
10x [PA 仃ahiti) - PA (Darwi n) ] / Std Dev Diff
* Note
PA (Tahiti) - FA (Detrain)〔° 加加.D请*
SOI Calculatio n formula: 10x [PA 仃ahiti) - PA (Darwi n)] / Std Dev Diff where: PA() = the Pressure Anomaly = monthly mean minus long-term mean
(1887-1989 ba period)
St.Dev.Diff. = Standard Deviation of the Difference (1887-1989 ba period) A Troup SOI
of -10 means the SOI is 1 standard deviation on the negative side of the Ion g-term mea n for that mon th. Troup's mon thly SOI from 1876 on wards is derived from no rmalid Tahiti mi nus Darwin mea n a level pressure (mslp)
NCC SOI Calculatio n
The National Climate Centre (NCC) have a revid SOI calculation although still bad on the Troup formula.
The formula for calculating the NCC 1933-92 ba period SOI is:10x [PA (Tahiti)-
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PA (Darwi n)] / Std Dev Diff
fighting是什么意思where: PA() = the Pressure Ano maly
=mon thly mean minus lon g-term mean (1933-1992 ba period)
St.Dev.Diff. = Sta ndard deviation of the differe nee (1933-1992 ba period)
Refere nee
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A.J. Troup (1965) The Southern Oscillation. Quarterly Journel of Royal Meteorological Society. 91,490-506.
Note: The calculations differ slightly from tho issued in some other centres where the value may not be multiplied by 10.
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Last updated: 29 June 2010
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