Monday, March 9, 2015

New paper finds correlation between solar activity, temperature, & East Asian Monsoon over past 1300 years

A new paper published in Global and Planetary Change finds a link between reconstructed temperatures of the Japan Sea and solar activity over the past 1300 years. The authors also find the strength of the East Asian Monsoon related to solar activity and the phase of the Pacific Decadal Oscillation (PDO). 

The paper follows on the heels of another paper published last week finding Indian Summer Monsoon failures "synchronize well with abrupt changes in solar activity," which may represent another potential solar amplification mechanism by which small changes in solar activity are amplified to large-scale effects on climate. 

Top graph shows reconstructed temperatures, MCA= Medieval Climate Anomaly (Medieval Warm Period), LIA = Little Ice Age, second graph shows changes in solar activity (Total Solar Irradiance or TSI), arrows show corresponding trends between temperatures and solar activity. Next three graph show proxies of precipitation & the East Asia monsoon, which also show correlation to solar activity. 

We estimated SST and SSS of the East/Japan Sea over the last 1300 years.
East Asia monsoon variability has been reconstructed over the period.
A strengthened summer monsoon occurred for the MCA at time of negative PDO.
Asian monsoon failure started at the end of the MCA and extended to the LIA.


We have reconstructed decadally-resolved continuous sea surface temperature and seawater δ18O (hence salinity) records over the last 1300 years from alkenone and planktonic foraminiferal oxygen isotope ratio analyses of the East Sea/Japan Sea marine sediments to investigate East Asia monsoon variability. Comparisons of the records with other paleoclimate records indicate a possible connection between changes in the mid-latitude East Asia monsoon and Pacific Decadal Oscillation (PDO) over this period. The results show that during the Medieval Climate Anomaly when the PDO index was negative, East Asia was characterized by surface warming with a strengthened summer monsoon. Summer monsoon-related precipitation increased and pluvials possibly dominated in the region at that time. Onset of Asia monsoon failure and severe drought occurred at the end of the MCA and extended to the Little Ice Age when the PDO became positive.

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