Acknowledgements
The authors are grateful to Zhouqing Xie, Senchao Lai and Benjamin Gilfedder for assisting in the retrieval of historical data. J. C. G. M. acknowledges financial support from the State Agency for Research of the Spanish MCIU through the ”Center of Excellence Severo Ochoa” award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709) and the Ramon y Cajal Program (RYC-2016-19570). A.S.-L. acknowledges financial support from the European Research Council Executive Agency under the European Union’s Horizon 2020 Research and Innovation programme (Project ’ERC-2016-COG 726349 CLIMAHAL’).