A spatial model for return values of warm extremes in the high Arctic

• Published in: Quarterly Journal of the Royal Meteorological Society
• Main Authors: Messori, Gabriele, Wada, R., Woods, C.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Uppsala universitet, Luft-, vatten- och landskapslära 2020
• Subjects: Arctic; extreme value theory; moisture intrusions; return values; temperature extremes; Meteorology and Atmospheric Sciences; Meteorologi och atmosfärforskning
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-439185; https://doi.org/10.1002/qj.3877

Wintertime warm extremes in the high Arctic, primarily associated with intrusions of moist airmasses from the midlatitudes, have occurred with an ostensibly high frequency in recent years. Here, we compute the temperature anomaly return values associated with such events for long return times. Our approach, which we term space-time maxima-exposure (STM-E), improves on conventional extreme value estimates performed on a single-location basis by explicitly taking into account the spatial structure of the moisture intrusions driving the temperature extremes. We specifically show that the STM-E approach provides spatially smoother return value estimates, a lower uncertainty in the parameters of the extreme value distribution fits and mitigates the single-location underestimation of the magnitude of return values of temperature extremes. De två första författarna delar förstaförfattarskapet