Figure - available from: Climatic Change
This content is subject to copyright. Terms and conditions apply.
Left: Ensemble of simulated annual CAO days from 2015 to 2054 for three future scenarios: SSP126, SSP245, and SSP585. Right: Difference between each SSP and the mean annual number of CAO days from 1979 to 2014.
Source publication
Historical and future simulated temperature data from five climate models in the Coupled Model Intercomparing Project Phase 6 (CMIP6) are used to understand how climate change might alter cold air outbreaks (CAOs) in the future. Three different shared socioeconomic pathways (SSPs), SSP126, SSP245, and SSP585, are examined to identify potential fluc...
Similar publications
Sudden-stratospheric-warming (SSW) events are often followed by significant weather and climate impacts at the surface. By affecting the North Atlantic Oscillation (NAO), SSWs can lead to periods of extreme cold in parts of Europe and North America. Previous studies have used observations and free-running climate models to try to identify features...
Citations
... In contrast, cold extremes have generally become less frequent and severe across most of the U.S., with these trends also projected to continue (van Oldenborgh et al 2019, Smith andSheridan 2020, Blackport et al 2022). However, natural variability will continue to drive widespread cold air outbreaks, such as the February 2021 cold wave, though they will likely be relatively warmer and less frequent than present (Gao et al 2015, Smith and Sheridan 2021, Blackport et al 2022, Smith et al 2022. ...
Several recent widespread temperature extremes across the United States have been associated with power outages, disrupting access to electricity at times that are critical for the health and well-being of communities. Building resilience into the energy infrastructure to such extremes needs a comprehensive understanding of their spatial and temporal characteristics. In this study, we systematically quantify the frequency, extent, duration and intensity of widespread temperature extremes and their associated energy demand in the six North American Electric Reliability Corporation (NERC) regions using ERA5 reanalysis data. We show that every region has experienced hot or cold extremes that affected nearly their entire extent, imposing simultaneous stresses on the system, and such events are associated with substantially higher energy demand. The western U.S. experienced significant increases in the frequency (123%), extent (32%), duration (55%) and intensity (29%) for hot extremes and Texas experienced significant increases in the frequency (132%) of hot extremes. The frequency of cold extremes is decreasing across most regions without substantial changes in other characteristics. Using power outage data, we show that recent widespread extremes in nearly every region have coincided with power outages, and such outages account for between 12-52% of all weather-related outages in the past decade depending on the region. Importantly, we find that solar potential is significantly higher during widespread hot extremes in all six regions and during widespread cold extremes in five of the six regions. Further, wind potential is significantly higher during widespread hot or cold extremes in at least three regions. Our findings indicate that increased solar and wind capacity could be leveraged to meet the higher energy demand during such widespread extremes, improving the resilience and reliability of our energy systems in addition to limiting carbon emissions.
Intense air mass transformations take place when cold, dry Arctic air masses move southward from the closed sea ice onto the much warmer ice-free Arctic ocean during marine cold air outbreaks (MCAOs). In spite of intensive research on MCAOs during recent years, the temporal rates of diabatic heating and moisture uptake relevant also for cloud formation/dissipation have not been measured along MCAO flows. Instead, reanalyses have typically been used for climatological investigations of MCAOs or to supply higher-resolution models with lateral boundary conditions and time-dependent forcings. Meanwhile, the uncertainties connected to those datasets remain unclear. Here, we present height-resolved observations of diabatic heating rates, moisture uptake, and cloud evolution measured in a quasi-Lagrangian manner. The investigated specific MCAO was observed on 01 April 2022 during the HALO-(AC)3 airborne campaign that was conducted in spring 2022. Shortly after passing the ice edge, maximum diabatic heating rates larger than 6 K h−1 and moisture uptake of more than 0.3 g kg−1 h−1 were measured close above the ocean surface. As the air mass continued its drift southwards, clouds started to form and vertical mixing within the steadily deepening boundary layer was intensified. The quasi-Lagrange observations are compared with reanalysis data from the European Centre for Medium-Range Weather Forecasts (ECMWF) latest global reanalysis ERA5 and the Copernicus Arctic Regional Reanalysis (CARRA). It was found that the mean absolute errors (MAEs) of ERA5 versus CARRA data are 60 % higher for air temperature over sea ice (1.4 K versus 0.9 K), and 70 % higher for specific humidity over ice-free ocean (0.12 g kg−1 versus 0.07 g kg−1 ). We relate these differences not only to issues with representations of the marginal ice zone and corresponding surface fluxes in ERA5, but also to the cloud scheme producing excess liquid-bearing clouds and precipitation, causing a too-dry marine boundary layer. Overall, the combination of CARRA’s high spatial resolution, an improved handling of cold surfaces, and the demonstrated higher fidelity towards the observations, make it a well-suited candidate for further investigations of Arctic air mass transformations.
