@article {5004,
	title = {Winter warming of McMurdo Dry Valleys soils},
	journal = {Antarctic Science},
	year = {2025},
	month = {01/2025},
	pages = {1-18},
	abstract = {<p>Continuous permafrost is present across the McMurdo Dry Valleys of southern Victoria Land, Antarctica. While summer active-layer thaw is common in the low-elevation portions of the Dry Valleys, active layers have not significantly thickened over time. However, in some locations, coastal Antarctic permafrost has begun to warm. Here, based on soil and meteorological measurements from 1993 to 2023, we show that wintertime soil temperatures have increased across multiple sites in the Dry Valleys, at rates exceeding the pace of summer soil warming. Linear warming trends over time are significant (P \&lt; 0.05) at six of seven soil monitoring sites. Winter warming is strongly correlated with increased numbers of down-valley wind events (Foehn/katabatics), but it may also be driven by increased incident longwave radiation at some stations (although winter longwave increase is not significant over time). While down-valley wind events increase winter warming, when down-valley wind events are excluded from the record, winter soil warming remains persistent and significant, suggesting that Antarctic soils are experiencing less cold winters over time in response to regional warming. Together, these observations suggest that some Antarctic permafrost may be approaching a transition to discontinuous permafrost in some regions as winter freezing intensity is reduced over time.</p>},
	keywords = {LTER-MCM, Antarctica, Foehn wind, katabatic wind, McMurdo Dry Valleys, microclimate, permafrost},
	issn = {0954-1020},
	doi = {10.1017/S0954102024000488},
	url = {https://www.cambridge.org/core/product/identifier/S0954102024000488/type/journal_article},
	author = {Fowler, Gavin and Joseph S. Levy}
}
@article {4691,
	title = {Episodic basin-scale soil moisture anomalies associated with high relative humidity events in the McMurdo Dry Valleys, Antarctica},
	journal = {Antarctic Science},
	year = {2021},
	month = {08/2021},
	pages = {1-15},
	abstract = {<p>Outside of hydrologically wetted active layer soils and humidity-sensitive soil brines, low soil moisture is a limiting factor controlling biogeochemical processes in the McMurdo Dry Valleys. But anecdotal field observations suggest that episodic wetting and darkening of surface soils in the absence of snowmelt occurs during high humidity conditions. Here, I analyse long-term meteorological station data to determine whether soil-darkening episodes are present in the instrumental record and whether they are, in fact, correlated with relative humidity. A strong linear correlation is found between relative humidity and soil reflectance at the Lake Bonney long-term autonomous weather station. Soil reflectance is found to decrease annually by a median of 27.7\% in response to high humidity conditions. This magnitude of darkening is consistent with soil moisture rising from typical background values of \&lt; 0.5 wt.\% to 2\&ndash;3 wt.\%, suggesting that regional atmospheric processes may result in widespread soil moisture generation in otherwise dry surface soils. Temperature and relative humidity conditions under which darkening is observed occur for hundreds of hours per year, but are dominated by episodes occurring between midnight and 07h00 local time, suggesting that wetting events may be common, but are not widely observed during typical diel science operations.</p>},
	keywords = {LTER-MCM, deliquescence, hydrology, microclimate, micrometeorology, pedology, remote sensing},
	issn = {0954-1020},
	doi = {10.1017/S0954102021000341},
	url = {https://www.cambridge.org/core/product/identifier/S0954102021000341/type/journal_article},
	author = {Joseph S. Levy}
}
