Recent Temperature Change on the Juneau Icefield – GSA 2020 Connects Online

Recent Temperature Change on the Juneau Icefield – GSA 2020 Connects Online

As one of the largest icefields in the world, the recent mass loss from the Juneau Icefield
(JIF) in Southeast Alaska will transform the local environment, hydrologic system, and will
contribute to global sea level rise. To better understand the climatic context of these
changes, our study aims to characterize recent changes in the surface temperature of the
JIF. We combine decades-long temperature records from stations across the Icefield,
produced and maintained by the Juneau Icefield Research Program, with reanalysis
products, to examine trends in the annual mean and seasonal surface temperatures over the
last 50 years. We find coherent multi-annual variability and trends between the stations
across the Icefield and with the regional estimates from reanalysis. Annual mean
temperature on the Icefield has been increasing at about twice the rate of Earth’s global
average. Interestingly, trends in winter-time temperature on the Icefield are about double the
annual average, while summer-time shows little trend over the interval. There is some
indication of elevation-dependence in these trends. These results have implications for the
source of recently documented negative anomalies in the glacier mass balance of the
icefield. We investigate possible sources of the seasonal and elevation dependence of these
warming trends. Our results have implications for the nature of recent glacier changes in the
region.

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