A review of past changes in extratropical cyclones in the northern hemisphere and what can be learned for the future

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Christoph C. Raible ◽  
Joaquim G. Pinto ◽  
Patrick Ludwig ◽  
Martina Messmer
Keyword(s):  
Northern Hemisphere ◽  
Extratropical Cyclones ◽  
The Future

scholarly journals The influence of solar wind on extratropical cyclones – Part 1: Wilcox effect revisited

2009 ◽  
Vol 27 (1) ◽  
pp. 1-30 ◽  
Author(s):  
P. Prikryl ◽  
V. Rušin ◽  
M. Rybanský
Keyword(s):  
Time Series ◽  
Solar Wind ◽  
Northern Hemisphere ◽  
High Speed ◽  
Coronal Holes ◽  
Extratropical Cyclones ◽  
Sector Boundary ◽  
Speed Solar Wind ◽  
The Mean ◽  
High Speed Solar Wind

Abstract. A sun-weather correlation, namely the link between solar magnetic sector boundary passage (SBP) by the Earth and upper-level tropospheric vorticity area index (VAI), that was found by Wilcox et al. (1974) and shown to be statistically significant by Hines and Halevy (1977) is revisited. A minimum in the VAI one day after SBP followed by an increase a few days later was observed. Using the ECMWF ERA-40 re-analysis dataset for the original period from 1963 to 1973 and extending it to 2002, we have verified what has become known as the "Wilcox effect" for the Northern as well as the Southern Hemisphere winters. The effect persists through years of high and low volcanic aerosol loading except for the Northern Hemisphere at 500 mb, when the VAI minimum is weak during the low aerosol years after 1973, particularly for sector boundaries associated with south-to-north reversals of the interplanetary magnetic field (IMF) BZ component. The "disappearance" of the Wilcox effect was found previously by Tinsley et al. (1994) who suggested that enhanced stratospheric volcanic aerosols and changes in air-earth current density are necessary conditions for the effect. The present results indicate that the Wilcox effect does not require high aerosol loading to be detected. The results are corroborated by a correlation with coronal holes where the fast solar wind originates. Ground-based measurements of the green coronal emission line (Fe XIV, 530.3 nm) are used in the superposed epoch analysis keyed by the times of sector boundary passage to show a one-to-one correspondence between the mean VAI variations and coronal holes. The VAI is modulated by high-speed solar wind streams with a delay of 1–2 days. The Fourier spectra of VAI time series show peaks at periods similar to those found in the solar corona and solar wind time series. In the modulation of VAI by solar wind the IMF BZ seems to control the phase of the Wilcox effect and the depth of the VAI minimum. The mean VAI response to SBP associated with the north-to-south reversal of BZ is leading by up to 2 days the mean VAI response to SBP associated with the south-to-north reversal of BZ. For the latter, less geoeffective events, the VAI minimum deepens (with the above exception of the Northern Hemisphere low-aerosol 500-mb VAI) and the VAI maximum is delayed. The phase shift between the mean VAI responses obtained for these two subsets of SBP events may explain the reduced amplitude of the overall Wilcox effect. In a companion paper, Prikryl et al. (2009) propose a new mechanism to explain the Wilcox effect, namely that solar-wind-generated auroral atmospheric gravity waves (AGWs) influence the growth of extratropical cyclones. It is also observed that severe extratropical storms, explosive cyclogenesis and significant sea level pressure deepenings of extratropical storms tend to occur within a few days of the arrival of high-speed solar wind. These observations are discussed in the context of the proposed AGW mechanism as well as the previously suggested atmospheric electrical current (AEC) model (Tinsley et al., 1994), which requires the presence of stratospheric aerosols for a significant (Wilcox) effect.

scholarly journals Multiyear Composite View of Ozone Enhancements and Stratosphere-to-Troposphere Transport in Dry Intrusions of Northern Hemisphere Extratropical Cyclones

2017 ◽  
Vol 122 (24) ◽  
pp. 13,436-13,457 ◽  
Author(s):  
Lyatt Jaeglé ◽  
Robert Wood ◽  
Krzysztof Wargan
Keyword(s):  
Northern Hemisphere ◽  
Extratropical Cyclones ◽  
Dry Intrusions

Strategies for high-latitude northern hemisphere CO2 sampling now and in the future

2009 ◽  
Vol 56 (8-10) ◽  
pp. 523-532 ◽  
Author(s):  
Andrew Lenton ◽  
Laurent Bopp ◽  
Richard J. Matear
Keyword(s):  
Northern Hemisphere ◽  
High Latitude ◽  
The Future

scholarly journals The Future of Midlatitude Cyclones

2019 ◽  
Vol 5 (4) ◽  
pp. 407-420 ◽  
Author(s):  
Jennifer L. Catto ◽  
Duncan Ackerley ◽  
James F. Booth ◽  
Adrian J. Champion ◽  
Brian A. Colle ◽  
...  
Keyword(s):  
Vertical Structure ◽  
Climate Models ◽  
Future Research ◽  
Extratropical Cyclones ◽  
Latent Heating ◽  
Climate Conditions ◽  
Structure Characteristics ◽  
Regional Impacts ◽  
Climate Simulations ◽  
The Future

Abstract Purpose of Review This review brings together recent research on the structure, characteristics, dynamics, and impacts of extratropical cyclones in the future. It draws on research using idealized models and complex climate simulations, to evaluate what is known and unknown about these future changes. Recent Findings There are interacting processes that contribute to the uncertainties in future extratropical cyclone changes, e.g., changes in the horizontal and vertical structure of the atmosphere and increasing moisture content due to rising temperatures. Summary While precipitation intensity will most likely increase, along with associated increased latent heating, it is unclear to what extent and for which particular climate conditions this will feedback to increase the intensity of the cyclones. Future research could focus on bridging the gap between idealized models and complex climate models, as well as better understanding of the regional impacts of future changes in extratropical cyclones.

Internal variability of the Arctic Oscillation and its projections

2020 ◽  
Author(s):  
Annalisa Cherchi ◽  
Paolo Oliveri ◽  
Aarnout van Delden
Keyword(s):  
Northern Hemisphere ◽  
Arctic Oscillation ◽  
Internal Variability ◽  
The Arctic ◽  
Positive Phase ◽  
Cmip5 Models ◽  
Modes Of Variability ◽  
The Future ◽  
The Arctic Oscillation

<p>The Arctic Oscillation (AO) is one of the main modes of variability of the Northern Hemisphere winter, also referred as Northern Annular Mode (NAM). The positive phase of the AO is characterized by warming/cooling over Northern Eurasia and the United States and cooling over Canada, especially over eastern Canada. Its positive phase is also characterized by very dry conditions over the Mediterranean and wet conditions over Northern Europe. A positive trend of the AO is observed for the period 1951-2011 and it is captured in CMIP5 models only when GHG-only forcing are included. In CMIP5 models the change expected is mostly mitigated by the effects of the aerosols. When considering AR5 scenarios, the AO is projected to become more positive in the future, though with a large spread among the models.</p><p>Overall the spread in the representation of the AO variability and trend is large also in experiments with present-day conditions, likely associated with the large internal variability. Unique tools to identify and measure the role of the internal variability in the model representation of the large-scale modes of variability are large ensembles where multiple members are built with different initial conditions.</p><p>Here we use the NCAR Community Model Large Ensemble (CESM-LE) composing the historical period (1920-2005) to the future (2006-2100) in a RCP8.5 scenario to measure the role of the internal variability in shaping AO variability and changes. Potential predictability of the AO index is quantified in the historical and future periods, evidencing how the members spread remain large without specific trends in these characteristics. Preliminary results indicate that the internal variability has large influence on the AO changes and related implications for the Northern Hemisphere climate.</p>

Monsoon dynamics in past and future climates: the Holocene is not an analogue of future projections

2020 ◽  
Author(s):  
Roberta D'Agostino ◽  
Juergen Bader ◽  
Josephine Brown ◽  
Simona Bordoni ◽  
David Ferreira ◽  
...  
Keyword(s):  
Atmospheric Circulation ◽  
Northern Hemisphere ◽  
Hydrological Cycle ◽  
Dynamic Responses ◽  
Mean Flow ◽  
The Holocene ◽  
Temperature And Precipitation ◽  
The Future ◽  
Future Warming ◽  
The Relationship

<p><span>In recent decades the paleo-modelling community has sought to identify past warm climates that could provide analogues for greenhouse induced warming. In spite of some similarities in temperature distributions (e.g. Pliocene, Eocene, Cretaceous and summertime Northern Hemisphere mid-Holocene), however, it is unlikely that any past epoch can provide detailed insight into future warming, especially in terms of changes in the hydrological cycle. Reviewing recent work, we show that changes in the atmospheric circulation can dramatically alter the relationship between temperature and precipitation, weakening the possibility for useful climate analogs as envisioned in the literature. We present results of moisture budget decomposition from mid-Holocene and Representative Pathways Scenario RCP8.5, two climates in which monsoons are stronger and wider than the pre-Industrial era. We find that Northern Hemisphere monsoons are much stronger and wider during the Holocene than what projected for the end of the 21st century. This is because the thermodynamic (i.e. moisture changes) and dynamic responses (i.e. mean-flow changes) reinforce each other in the mid-Holocene while they partially cancel out in the future climate. Therefore, the Holocene does not represent an analogue of the future given the opposite dynamical responses in the two climates. Consistent with other studies, our work highlights that changes in atmospheric circulation are the major source of uncertainty for future projection of hydrological cycle, especially at regional scales.</span></p>

scholarly journals A PV Perspective on the Vertical Structure of Mature Midlatitude Cyclones in the Northern Hemisphere

2012 ◽  
Vol 69 (2) ◽  
pp. 725-740 ◽  
Author(s):  
Jana Čampa ◽  
Heini Wernli
Keyword(s):  
Northern Hemisphere ◽  
Potential Vorticity ◽  
Vertical Structure ◽  
Potential Temperature ◽  
Vertical Cylinder ◽  
Mature Stage ◽  
Extratropical Cyclones ◽  
Surface Acting ◽  
Regional Variability ◽  
Stratospheric Intrusion

Abstract Development of extratropical cyclones can be seen as an interplay of three positive potential vorticity anomalies: an upper-level stratospheric intrusion, low-tropospheric diabatically produced potential vorticity (PV), and a warm anomaly at the surface acting as a surrogate PV anomaly. This study, based on the interim ECMWF Re-Analysis (ERA-Interim) dataset, quantifies the amplitude of the PV anomalies of mature extratropical cyclones in different regions in the Northern Hemisphere on a climatological basis. A tracking algorithm is applied to sea level pressure (SLP) fields to identify cyclone tracks. Surface potential temperature anomalies Δθ and vertical profiles of PV anomalies ΔPV are calculated at the time of the cyclones’ minimum SLP in a vertical cylinder around the surface cyclone center. To compare the cyclones’ characteristics they are grouped according to their location and intensity. Composite ΔPV profiles are calculated for each region and intensity class at the time of minimum SLP and during the cyclone intensification phase. In the mature stage all three anomalies are on average larger for intense than for weak winter cyclones [e.g., 0.6 versus 0.2 potential vorticity units (PVU; 1 PVU = 10−6 K kg−1 m2 s−1) at lower levels, and 1.5 versus 0.5 PVU at upper levels]. The regional variability of the cyclones’ vertical structure and the profile evolution is prominent (cyclones in some regions are more sensitive to the amplitude of a particular anomaly than in other regions). Values of Δθ and low-level ΔPV are on average larger in the western parts of the oceans than in the eastern parts. Results for summer are qualitatively similar, except for distinctively weaker surface Δθ values.

Marine cold-air outbreaks in the future: an assessment of IPCC AR4 model results for the Northern Hemisphere

2007 ◽  
Vol 30 (7-8) ◽  
pp. 871-885 ◽  
Author(s):  
Erik W. Kolstad ◽  
Thomas J. Bracegirdle
Keyword(s):  
Northern Hemisphere ◽  
Cold Air ◽  
The Future ◽  
Ipcc Ar4 ◽  
Cold Air Outbreaks

scholarly journals Thermodynamic Phase and Ice Cloud Properties in Northern Hemisphere Winter Extratropical Cyclones Observed by Aqua AIRS

2015 ◽  
Vol 54 (11) ◽  
pp. 2283-2303 ◽  
Author(s):  
Catherine M. Naud ◽  
Brian H. Kahn
Keyword(s):  
Northern Hemisphere ◽  
Cloud Cover ◽  
Frontal Region ◽  
Extratropical Cyclones ◽  
Ice Clouds ◽  
Ice Cloud ◽  
Cloud Properties ◽  
Hemisphere Winter ◽  
Thermodynamic Phase ◽  
Northern Hemisphere Winter

AbstractIce cloud properties in Northern Hemisphere winter extratropical cyclones are examined using the Atmospheric Infrared Sounder (AIRS), version 6, cloud products. The cloud thermodynamic phase product indicates that warm frontal clouds are dominated by ice, liquid-phase clouds occur outside of the warm frontal region, and supercooled or mixed-phase clouds are found in the southwestern quadrant of the cyclones. Stratiform ice clouds populate the warm frontal region and portions of the cold sector while convective ice clouds populate southeastern portions of the warm front and the southeastern quadrant. Total cloud cover is smaller in land cyclones than in ocean cyclones, especially in the southwestern quadrant and the warm frontal region. Ice cloud cover is less over land in the warm frontal region, because land cyclones are generally weaker and drier than ocean cyclones. The impact of cyclone average precipitable water (PW) and the magnitude of 850-hPa vertical ascent ω850 on the thermodynamic phase, occurrence of stratiform or convective ice cloud, ice particle effective diameter, optical thickness, and cloud-top temperature are discussed. When comparing land and ocean cyclones with similar PW and ω850, ice cloud coverage is found to be greater over land. Convective ice cloud occurs more often and is deeper over land. Supercooled cloud appears to persist to colder temperatures over ocean than over land, especially in the warm frontal region. These results suggest that, over land, ice cloud formation in warm fronts is possibly more efficient because of a greater aerosol amount from local or regional sources.

scholarly journals TIGGE: Comparison of the Prediction of Northern Hemisphere Extratropical Cyclones by Different Ensemble Prediction Systems

2010 ◽  
Vol 25 (3) ◽  
pp. 819-836 ◽  
Author(s):  
Lizzie S. R. Froude
Keyword(s):  
Northern Hemisphere ◽  
Propagation Speed ◽  
Research Programme ◽  
Ensemble Prediction ◽  
Extratropical Cyclones ◽  
Ensemble Prediction System ◽  
Cyclone Intensity ◽  
Ensemble Mean ◽  
Environmental Prediction ◽  
And Control

Abstract The Observing System Research and Predictability Experiment (THORPEX) Interactive Grand Global Ensemble (TIGGE) is a World Weather Research Programme project. One of its main objectives is to enhance collaboration on the development of ensemble prediction between operational centers and universities by increasing the availability of ensemble prediction system (EPS) data for research. This study analyzes the prediction of Northern Hemisphere extratropical cyclones by nine different EPSs archived as part of the TIGGE project for the 6-month time period of 1 February 2008–31 July 2008, which included a sample of 774 cyclones. An objective feature tracking method has been used to identify and track the cyclones along the forecast trajectories. Forecast verification statistics have then been produced [using the European Centre for Medium-Range Weather Forecasts (ECMWF) operational analysis as the truth] for cyclone position, intensity, and propagation speed, showing large differences between the different EPSs. The results show that the ECMWF ensemble mean and control have the highest level of skill for all cyclone properties. The Japanese Meteorological Administration (JMA), the National Centers for Environmental Prediction (NCEP), the Met Office (UKMO), and the Canadian Meteorological Centre (CMC) have 1 day less skill for the position of cyclones throughout the forecast range. The relative performance of the different EPSs remains the same for cyclone intensity except for NCEP, which has larger errors than for position. NCEP, the Centro de Previsão de Tempo e Estudos Climáticos (CPTEC), and the Australian Bureau of Meteorology (BoM) all have faster intensity error growth in the earlier part of the forecast. They are also very underdispersive and significantly underpredict intensities, perhaps due to the comparatively low spatial resolutions of these EPSs not being able to accurately model the tilted structure essential to cyclone growth and decay. There is very little difference between the levels of skill of the ensemble mean and control for cyclone position, but the ensemble mean provides an advantage over the control for all EPSs except CPTEC in cyclone intensity and there is an advantage for propagation speed for all EPSs. ECMWF and JMA have an excellent spread–skill relationship for cyclone position. The EPSs are all much more underdispersive for cyclone intensity and propagation speed than for position, with ECMWF and CMC performing best for intensity and CMC performing best for propagation speed. ECMWF is the only EPS to consistently overpredict cyclone intensity, although the bias is small. BoM, NCEP, UKMO, and CPTEC significantly underpredict intensity and, interestingly, all the EPSs underpredict the propagation speed, that is, the cyclones move too slowly on average in all EPSs.

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