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We simulated Arctic climate using a high‐resolution implementation of WRF driven by HadGEM‐ES2 climate model outputs, following IPCC5 warming scenarios RCP 2.6, RCP 4.5 and RCP 8.5. The downscaled results indicate that, by the end‐of‐century, there are no significant changes in the average minimum central pressures or total number of winter Arctic cyclones. However, there are significant changes in the spatial patterns. For example, the frequency and vorticity of cyclones tend to increase over the western Arctic. Due to the poleward movement of the polar frontal zone and the increased low‐level tropospheric baroclinicity, more cyclones are expected to form within the Arctic Basin and migrate into the western‐central Arctic. We expect about 39% more cyclone tracks forming and dying in the Arctic Basin under RCP8.5, compared to present climate. On the other hand, with the reduced baroclinicity in the entire troposphere, there is a reduced genesis, frequency, and vorticity of cyclones over the Atlantic Arctic. Moreover, the depth of cyclones shows a robust decrease over the Arctic Basin, suggesting weakened eddy kinetic energy. With increasing greenhouse gases, the changes in cyclone vorticities and their depths tend to be stronger. In addition, the high resolution Polar WRF results demonstrate that changes in cyclone track density and intensities consistently become more pronounced with increasing radiative forcing. Plain Language Summary: We used advanced climate models to simulate how the Arctic climate might change in the future. We focused on the scenarios outlined by the Intergovernmental Panel on Climate Change (IPCC) and their effects on Arctic cyclones. Our results show that, by the end of the 21st century, the overall characteristics of winter Arctic cyclones do not experience significant changes. However, there are interesting regional variations. The frequency and vorticity (spinning) force of cyclones are projected to decrease over the Atlantic Arctic but increase over the western Arctic. Simultaneously, fewer cyclones are expected over the Atlantic Arctic. Furthermore, the depth of cyclones over the Arctic Basin is expected to decrease, suggesting a weakening in their strength. In IPCC scenarios with higher emissions, the changes in cyclone characteristics become more pronounced. Similar trends are also observed in results from the latest climate models. Key Points: The frequency and vorticity of cyclones tend to increase (decrease) over the western‐central (Atlantic) Arctic under climate scenariosThe decreasing cyclone depths in the Arctic Basin suggest a weakened eddy kinetic energy in warming climate scenariosThe poleward shift of the frontal zone and increased baroclinicity lead to 39% more cyclones forming and dying in the Arctic Basin under the warmest scenario [ABSTRACT FROM AUTHOR]

We show that the winter Beaufort High (BH) index defined by sea level pressure (SLP) has a robust negative trend under the scenarios SSP5‐8.5 and SSP2‐4.5, with a reduction by about 5 hPa and 2 hPa, respectively, by the end of the 21st century. The negative trends in the BH SLP are associated with the changes in the background SLP over the Arctic basin. However, the vorticity of the winter BH tends to intensify under SSP5‐8.5, but shows no robust increase under SSP2‐4.5. The intensification is associated with the enhanced ridge over the Western Arctic. Therefore, it is necessary to take into account the dynamic aspects of the BH, such as vorticity. Based on this assessment, under the most likely emissions scenario, the winter BH is likely to weaken through the 21st century, in terms of SLP, but shows no robust changes in term of vorticity. Plain Language Summary: We used the latest IPCC global climate model outputs to investigate the wintertime changes in the Beaufort High (BH). Under the climate change scenarios, during winter, the sea level pressure (SLP) over the BH region is expected to decrease. The SLP reduction is up to 5 hPa by the end‐of‐the‐century. Thus, the BH seems to become weaker. However, its vorticity tends to increase under SSP5‐8.5, mostly due to the intensification of the ridge over the western North America. Key Points: The Beaufort High (BH) index defined by sea level pressure (SLP) decreases under warming climate scenariosMeanwhile, the BH vorticity tends to intensify due to the change in the ridge over the Western ArcticBesides the SLP, impact studies of the BH on the Arctic Ocean need to consider its dynamics such as vorticity [ABSTRACT FROM AUTHOR]

Changes in the volume transport of Atlantic water into the Arctic Ocean can affect the heat and mass balance in the central Arctic Ocean. To understand the impacts of Arctic storms on the inflow through Fram Strait, we implemented the NEMO ocean model for the Arctic Ocean, to simulate the decadal variations of the water volume transport through Fram Strait. The simulations suggest that the water inflow tends to be weaker in the decades of the 1960 and 2010s but stronger in the 1980s. The decadal variation is associated with decadal variability of the storm density in the Greenland Sea. When there is an increased storm density near Fram Strait, the southerly wind anomalies dominate the Atlantic water pathway. As a response, there is an increased Atlantic inflow through Fram Strait. Plain Language Summary: On decadal scales, Arctic storms near Fram Strait are highly correlated with the water volume transport into the Arctic Ocean through Fram Strait. When there are more storms near Fram Strait, the transport tends to increase. In addition, the heat flux associated with the water volume transport reflects the impacts of both the linear trend in ocean temperature and the decadal variation of water volume transport. Key Points: On a decadal scale, the storms in the Greenland Sea can affect the volume transport of Atlantic water inflow through Fram StraitAssociated heat flux reflects the impacts of both the linear trend in ocean temperature and the decadal variation of water volume transport [ABSTRACT FROM AUTHOR]

Fog simulation is a challenge due to the complex microphysical, radiative, and turbulent processes. C‐FOG (Coastal Fog) was a comprehensive experiment which aimed to improve our understanding and forecasting skill of fog in coastal areas of Atlantic Canada. An intermittent fog event, containing two fog periods occurring over the Grand Banks of Newfoundland beginning at 00:00 UTC on September 13, 2018, is investigated in this study. Our approach is to apply the Weather Research and Forecasting (WRF) model, in conjunction with a 1‐D model for the atmospheric boundary layer, PAFOG (Parameterized Fog model). Model results are evaluated against observations collected onboard the research vessel Hugh R. Sharp. We introduced an advection term to PAFOG to investigate the ability of the model to simulate the two‐level fog/stratus system and we developed a set of sensitivity experiments. Results suggest that PAFOG with the advection terms calculated from ERA5 shows a good ability to simulate intermittent fog caused by fog lifting as stratus, and by comparison, outperform results with advection terms derived from WRF simulations. Regarding the latter, in an experiment with high vertical resolution, WRF gives a delayed fog event, whereas with low vertical resolution, WRF gives descending stratus. Our results provide a possible methodology to study the detailed structure of fog/stratus using PAFOG, a sounding profile as initial conditions, and advection profiles derived from ERA5, with low computing cost. Key Points: PAFOG with advection terms has ability to simulate intermittent fog/stratus system by successfully simulating TKE and radiative coolingHigh vertical resolution in WRF suggests a delayed fog onset; with lower vertical resolution, WRF can simulate descending stratusA detailed inversion structure for the initial vertical profile plays an important role in resulting in success of the PAFOG simulation [ABSTRACT FROM AUTHOR]

In this study, a series of fog events that occurred near Halifax, Canada, during 20 June to 31 July 2016 are investigated using the Weather Research and Forecasting Model Version 3.8.1 (WRF), in comparison with in situ and satellite remotely sensed observations from the Moderate Resolution Imaging Spectroradiometer. We evaluate five planetary boundary layer (PBL) schemes available in WRF. Results show that these five PBL schemes lead to overestimates in liquid water content, especially the nonlocal schemes, and that they are biased early, in terms of the predicting the onset of fog, and late, in terms of fog dissipation, although their spatial patterns of fog are in good agreement with those suggested by Moderate Resolution Imaging Spectroradiometer imagery. The Kunkel equation is used to calculate visibility, based on WRF modeling of liquid water content. Comparisons with observed visibility show that this methodology sometimes fails to predict fog dissipation. We present a modification of this formulation for visibility that shows improved agreement with observations and more accurate fog dissipation. Continued improvements in the PBL scheme and visibility parameterization are needed for more accurate fog prediction. Key Points: Local schemes for planetary boundary layer seem to perform better in fog simulation than nonlocal schemes in WRF mesoscale modelThe re‐examined Kunkel equation with optimized new exponent simulates observed visibility better than the previous versionMYNN2.5 is best among the five WRF PBL schemes available in the WRF model to simulate fog over Canada Atlantic Waters [ABSTRACT FROM AUTHOR]

We conduct a sensitivity study of the North Atlantic cyclone climate, with respect to the cumulus parameterization (CP) and planetary boundary layer (PBL) schemes, applied in the dynamical downscaling of HadGEM2‐ES simulations using Polar Weather Research and Forecasting. A set of seven sensitivity experiments is conducted for 1979–2004 using these CP and PBL schemes. CP schemes are Kain‐Fritsch (KF), Zhang‐McFarlane (ZM), and the modified Tiedtke (TZ). PBL schemes are the local Mellor‐Yamada‐Janjić (MYJ), Mellor‐Yamada‐Nakanishi‐Niino Level 2.5 (MYNN2) schemes, and nonlocal Yonsei University (YSU) scheme. In terms of cyclone intensities, our results show that the fine‐resolution Weather Research and Forecasting simulations capture higher intensities of summer cyclones than the HadGEM2‐ES results, in better agreement with the ERA‐Interim reanalysis, and exhibit a weak sensitivity to CP and PBL schemes. However, the frequency of summer cyclones is quite sensitive to CP and PBL schemes. Four KF experiments suggest comparable numbers of cyclone tracks as derived from ERA‐Interim reanalysis data, which is about 21% more than the ZM‐MYJ or TZ experiments and 11% more than HadGEM2‐ES results. Larger tropospheric potential vorticity and more cyclogenesis in the KF simulation than in TZ or ZM simulations are associated with different cyclone triggering functions and different vertical distributions of heating. We also find increased cyclone activities over the North Atlantic in the YSU or MYNN2 schemes compared to MYJ, but results also depend on the KF CP scheme. This can be attributed to stronger vertical mixing in YSU and MYNN schemes, resulting in smaller static stability and enhanced atmospheric moisture. Key Points: The frequency of North Atlantic cyclones exhibits large sensitivity to the cumulus (CP) and planetary boundary layer (PBL) schemesThe intensity of North Atlantic summer cyclones is insensitive to the CP and PBL schemesLapse rate of potential temperature associated with CP, static stability, and turbulent moisture in the PBL has impact on cyclone activities [ABSTRACT FROM AUTHOR]

The abrupt deceleration of accelerated Greenland Ice Sheet (GrIS) melting since 2013, after a period of acceleration previously noted, is studied here. It is shown that the deceleration of GrIS melting since 2013 is due to the reduction in short‐wave solar radiation in the presence of increasing total cloud cover, which is driven by a more persistent positive summer North Atlantic Oscillation on the decadal time scale. By presenting the coherence with the temperature variability at the weather stations in Greenland, which have century‐long records, we deduce that the acceleration of GrIS melting during the early 2000s and the subsequent deceleration since 2013 will reoccur frequently on decadal time scales, with the amplitude nearly half of the multidecadal warming trend of the GrIS melt. It can reduce the mass loss from the GrIS on short to medium time scales but is unlikely to halt mass loss related to climate change in the future. This finding highlights the importance of internal climate variability on the mass budget of the GrIS and therefore on predictions of future global sea level change and may help to assist planning for associated social and economic consequences. Plain Language Summary: The Greenland Ice Sheet (GrIS) mass change and its contribution to the global sea level variability is a topic that naturally piques our curiosity. Since the satellite first captured the Greenland‐wide ice sheet mass variability in 2002, the GrIS experienced accelerated melting, leading to global sea level acceleration. The long‐term GrIS melting depends on climate change such as greenhouse warming. However, recently, this acceleration is slowed down due to the summer North Atlantic Oscillation phase changing to positive. We use century‐long surface temperature records as index to estimate the contribution of this slowdown phenomenon and find that the amplitude of this internal variability is nearly half of the multidecadal warming trend of the GrIS; therefore, this cycle can slow down but cannot stop the loss of the Greenland Ice Sheet mass at present and in the near future. This finding highlights the role of the internal variability of the GrIS on predictions of future global sea level change and the associated social and economic consequences. Key Points: Greenland Ice Sheet exhibits decelerated melt since 2013The deceleration is due to increased cloud during positive summer NAOThe accelerated and decelerated GrIS melt will reoccur on decadal time scale [ABSTRACT FROM AUTHOR]

We show that a weakened Beaufort High in late winter is becoming more common since the late 1980s, and this weakening is related to decadal changes in Northern Hemisphere ozone depletion. During this time, the stratospheric polar vortex has experienced a decadal northeastward displacement. Such displacement is associated with the variability of the East Asia‐eastern North America dipole. A positive Asia‐eastern North America dipole leads to zonal asymmetry in the ozone depletion with maximum loss over eastern Eurasia. Positive feedback with the zonally asymmetric ozone loss contributes to increased occurrence of the northeastward displacement of the stratospheric polar vortex. The northeastward displaced polar vortex enhances baroclinicity over the Eurasian Arctic and causes an increase in the frequency and intensity of cyclones and a decrease in anticyclones over the Eurasian Arctic. Concomitantly, the Beaufort High tends to have weakened. Key Points: A weakened winter Beaufort High has become more common since the late 1980s, which is related to decadal change of ozone depletionThe northeastward displaced stratospheric polar vortex results from the interactions of the polar vortex with the ozone depletionNortheastward displaced polar vortex causes an increase (decrease) in cyclones (anticyclones) over the Eurasian Arctic [ABSTRACT FROM AUTHOR]

The educational inclusion of rural–urban migrant children in Chinese urban schools has been promoted in the past decades. This paper provides a contextualized interpretation of recent policy developments governing large Chinese cities and evaluates its impact upon the status of migrant children's education. Drawing on data collected from 1,331 migrant children in urban inclusive schools, this study compared current migrant children's family backgrounds and psychological sense of belonging at school in relation to educational outcomes at the primary education level. Results showed that migrant children's socioeconomic status (SES) levels were slightly higher than their counterparts in inclusive schools and a salient SES stratification of migrant students was found. This correlates with students’ reports of fewer incidences of discrimination than hypothesized. Furthermore, capital in migrant families was positively associated with the psychological sense of belonging and academic achievement. These results reveal a significant change to migrant students’ SES as a result of the recent population control policy pertaining to China's large cities since 2014. Implications for research and educational practice, especially with at‐risk migrant students of low‐SES, are discussed. [ABSTRACT FROM AUTHOR]