Parameters common to the 8-parameter and 10-parameter models

arabian sea sst*: Based on average sea surface temperature of northwest Arabian Sea during January and February. Positively correlated: above normal SST means above normal monsoon.

eurasian snow cover: Based on Eurasian snow cover in December. Negatively correlated: more snow cover means less rainfall.

northwest europe temperature: Based on average mean temperatures during January in five stations over northwest Europe. Positively correlated.

south indian ocean sst: Based on difference between SST over southeast Indian Ocean and southwest Indian Ocean during March. Positively correlated.

east asian pressure: Derived from average surface pressure in February and March over east Asia. Positively correlated.

europe pressure gradient: Based on mean sea level pressure anomalies between northwest Europe and southwest Europe. Positively correlated.

50 h P a ** wind pattern during winter: Derived by measuring the longitudinal length of troughs and ridges at 50 hPa (20-25 kilometre altitude) over northern hemisphere in winter. Negatively correlated.

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