Possible impacts of climate change on fog in the Arctic and subpolar North Atlantic

Abstract

Abstract. A conventional parameterization of midlatitude warm fog occurrence, based on in situ observations, is employed to estimate marine surface visibility in the Arctic and North Atlantic from three datasets: an ensemble member of the Hadley Earth System (HadGEM2) model and a nested regional WRF simulation that follow historical and future emissions scenarios for 1979–2100, and the ERA-Interim reanalysis for 1979–2004. Over large scales (of an entire year and region), all three gridded datasets agree well in terms of variables like surface air temperature, whose systematic differences seem small by comparison with its predicted change over the course of this century. On the other hand, systematic differences are more apparent in large-scale estimates of relative humidity and visibility. Large differences are attributed to a sensitivity to representation bias that is inherent in the formulation of each individual model and analysis. Two simple linear calibrations are examined, both of which assume that an in situ based parameterization is broadly consistent with the use of marine (ICOADS) observations of air and dew point temperature as an error-free reference. A single-step calibration is considered that takes the mean and variance of ICOADS frequency distributions as a reference. A two-step calibration is also performed in which ICOADS collocations are taken as a reference for the ERA reanalysis, which in turn is taken as a large-scale reference for the 1979–2004 HadGEM2 and WRF simulations. Both linear calibrations are applied (locally in time and space to air and dew point temperature) to the future climate scenarios of HadGEM2 and WRF. Although ICOADS observations are not error-free and parameterized visibility estimates are unlikely to capture much more than half the variance found in observations, attempts are made to present consistent regional changes in the frequency of high relative humidity, as a proxy for warm fog occurrence. The large-scale decrease in visibility over the 21st century is in the range of 8 %–12 % in the Arctic and 0 %–5 % in the North Atlantic.

A review on factors influencing fog formation, classification, forecasting, detection and impacts

“…Eastern China has been reported to experience frequent winter fog events during the El Nino years due to anticyclonic conditions prevailing in the North West Pacific (NWP 1 ), in contrast the opposite of this happens during a La Nina event (Hu et al 2020 ). Climatic models following historical and future emission scenarios have predicted reduced marine surface visibility and increased humidity in the arctic and subpolar North Atlantic region for the latter part of the century, indicating dense fog occurrence in the area (Danielson et al 2020 ). Another regional climatic model has predicted the number of fog days to increase in the coastal areas of the Namib Desert and a decrease in the inland areas (Haensler et al 2011 ).…”

Rapid growth of Aitken-mode particles during Arctic summer by fog chemical processing and its implication

“…4 . Due to a changing climate in the Arctic, the frequency and duration of fogs are increasing ( 39 , 48 , 49 ). As a result, the observed growth phenomena and proposed mechanism may have substantial implications to better understand the radiative forcing of Arctic low-level clouds.…”

“…Due to a changing Arctic climate, NPF events and fog occurrence are predicted to increase, particularly in marginal sea ice zones ( 23 , 39–41 ). Accordingly, the rapid increase in <60 nm particles observed in our study may become a dominant source of CCN; thus, it is important to understand their linked processes in more detail.…”

A climatology of Arctic fog along the coast of East Greenland

“…Arctic fog frequency is expected to increase over the ocean due to the ongoing warming of the Arctic (e.g., Eastman & Warren, 2010b; Vavrus et al, 2011). Based on projected changes in temperature and relative humidity from future emission scenarios, Danielson et al (2020) estimated an overall decrease in visibility in the Arctic by 8–12% by the end of the century, which will become a sustained challenge for the growing aviation and marine transportation at high latitudes. Although trends in fog occurrence in East Greenland presented in this paper are spatially variable and only marginally significant, similar to the spatially varying trends across the Arctic (e.g., Eastman & Warren, 2010a; Hanesiak & Wang, 2005; Kawai et al, 2016; Khalilian, 2016), the 34‐year decreasing trend in visibility during fog at Danmarkshavn reflects a climatic signal possibly related to long‐term changes in regional sea ice and atmospheric conditions over Greenland (van Angelen et al, 2011).…”

“…Across the Arctic Ocean and coastal regions, fog is common and constitutes a hazard for all modes of transportation due to its low visibility, poor predictability and complex physical and dynamical processes (Gultepe et al, 2007; Gultepe et al, 2017; Smith & Stephenson, 2013). As sea ice area decreases, fog frequencies are expected to increase, in some predictions with 10% by the end of the century (Danielson et al, 2020; Palm et al, 2010; Vavrus et al, 2011). Despite the opening of new sea routes at high latitudes, fog will continue to be a logistic barrier to marine navigation (Dawson et al, 2017; Teufel & Sushama, 2022).…”