scholarly journals Meteorological conditions during the MOSAiC expedition

Elem Sci Anth ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Annette Rinke ◽  
John J. Cassano ◽  
Elizabeth N. Cassano ◽  
Ralf Jaiser ◽  
Dörthe Handorf
Keyword(s):  
Reanalysis Data ◽  
Early Spring ◽  
Meteorological Conditions ◽  
The Arctic ◽  
Positive Temperature ◽  
Storm Events ◽  
Radiative Fluxes ◽  
Near Surface ◽  
Cyclone Intensity ◽  
The Arctic Oscillation

This article sets the near-surface meteorological conditions during the Multidisciplinary drifting Observatory for the Study of Arctic Climate expedition in the context of the interannual variability and extremes within the past 4 decades. Hourly ERA5 reanalysis data for the Polarstern trajectory for 1979–2020 are analyzed. The conditions were relatively normal given that they were mostly within the interquartile range of the preceding 4 decades. Nevertheless, some anomalous and even record-breaking conditions did occur, particularly during synoptic events. Extreme cases of warm, moist air transported from the northern North Atlantic or northwestern Siberia into the Arctic were identified from late fall until early spring. Daily temperature and total column water vapor were classified as being among the top-ranking warmest/wettest days or even record-breaking based on the full record. Associated with this, the longwave radiative fluxes at the surface were extremely anomalous for these winter cases. The winter and spring period was characterized by more frequent storm events and median cyclone intensity ranking in the top 25th percentile of the full record. During summer, near melting point conditions were more than a month longer than usual, and the July and August 2020 mean conditions were the all-time warmest and wettest. These record conditions near the Polarstern were embedded in large positive temperature and moisture anomalies over the whole central Arctic. In contrast, unusually cold conditions occurred during the beginning of November 2019 and in early March 2020, related to the Arctic Oscillation. In March, this was linked with anomalously strong and persistent northerly winds associated with frequent cyclone occurrence to the southeast of the Polarstern.

scholarly journals Atmospheric teleconnections between the Arctic and the eastern Baltic Sea regions

2017 ◽  
Vol 8 (4) ◽  
pp. 1019-1030 ◽  
Author(s):  
Liisi Jakobson ◽  
Erko Jakobson ◽  
Piia Post ◽  
Jaak Jaagus
Keyword(s):  
Baltic Sea ◽  
Reanalysis Data ◽  
Specific Humidity ◽  
The Arctic ◽  
Positive Temperature ◽  
Strong Negative Correlation ◽  
Mild Winter ◽  
Baltic Sea Region ◽  
The Arctic Oscillation ◽  
Eastern Baltic

Abstract. The teleconnections between meteorological parameters of the Arctic and the eastern Baltic Sea regions were analysed based on the NCEP-CFSR and ERA-Interim reanalysis data for 1979–2015. The eastern Baltic Sea region was characterised by meteorological values at a testing point (TP) in southern Estonia (58° N, 26° E). Temperature at the 1000 hPa level at the TP have a strong negative correlation with the Greenland sector (the region between 55–80° N and 20–80° W) during all seasons except summer. Significant teleconnections are present in temperature profiles from 1000 to 500 hPa. The strongest teleconnections between the same parameter at the eastern Baltic Sea region and the Arctic are found in winter, but they are clearly affected by the Arctic Oscillation (AO) index. After removal of the AO index variability, correlations in winter were below ±0.5, while in other seasons there remained regions with strong (|R| > 0.5, p < 0.002) correlations. Strong correlations (|R| > 0.5) are also present between different climate variables (sea-level pressure, specific humidity, wind speed) at the TP and different regions of the Arctic. These teleconnections cannot be explained solely with the variability of circulation indices. The positive temperature anomaly of mild winter at the Greenland sector shifts towards east during the next seasons, reaching the Baltic Sea region in summer. This evolution is present at 60 and 65° N but is missing at higher latitudes. The most permanent lagged correlations in 1000 hPa temperature reveal that the temperature in summer at the TP is strongly predestined by temperature in the Greenland sector in the previous spring and winter.

scholarly journals Analysis of Arctic Spring Ozone Anomaly in the Phases of QBO and 11-year Solar Cycle for 1979–2011

2021 ◽  
Author(s):  
Yousuke Yamashita ◽  
Hideharu Akiyoshi ◽  
Masaaki Takahashi
Keyword(s):  
Solar Cycle ◽  
Climate Model ◽  
Polar Vortex ◽  
Reanalysis Data ◽  
Early Spring ◽  
The Arctic ◽  
Negative Anomaly ◽  
Late Winter ◽  
Quasi Biennial Oscillation ◽  
Biennial Oscillation

Arctic ozone amount in winter to spring shows large year-to-year variation. This study investigates Arctic spring ozone in relation to the phase of quasi-biennial oscillation (QBO)/the 11-year solar cycle, using satellite observations, reanalysis data, and outputs of a chemistry climate model (CCM) during the period of 1979&ndash;2011. For this duration, we found that the composite mean of the Northern Hemisphere high-latitude total ozone in the QBO-westerly (QBO-W)/solar minimum (Smin) phase is slightly smaller than those averaged for the QBO-W/Smax and QBO-E/Smax years in March. An analysis of a passive ozone tracer in the CCM simulation indicates that this negative anomaly is primarily caused by transport. The negative anomaly is consistent with a weakening of the residual mean downward motion in the polar lower stratosphere. The contribution of chemical processes estimated using the column amount difference between ozone and the passive ozone tracer is between 10&ndash;20% of the total anomaly in March. The lower ozone levels in the Arctic spring during the QBO-W/Smin years are associated with a stronger Arctic polar vortex from late winter to early spring, which is linked to the reduced occurrence of sudden stratospheric warming in the winter during the QBO-W/Smin years.

scholarly journals Atmospheric circulation and storm events in the Baltic Sea

2015 ◽  
Vol 7 (1) ◽  
Author(s):  
G. V. Surkova ◽  
Victor S. Arkhipkin ◽  
Alexander V. Kislov
Keyword(s):  
Baltic Sea ◽  
Wave Model ◽  
Recognition Algorithm ◽  
The Arctic ◽  
Storm Event ◽  
Storm Events ◽  
The Baltic Sea ◽  
Circulation Types ◽  
The Arctic Oscillation ◽  
The Baltic

AbstractThe storm events in the Baltic Sea are examined in connection with the main weather patterns grouped into the circulation types (CTs), and their changes in present climate. A calendar of storms was derived from results of wave model SWAN (Simulating WAves Nearshore) experiments for 1948-2011. Based on this calendar, a catalogue of atmospheric sea level pressure (SLP) fields was prepared for CTs from the NCEP/NCAR dataset. SLP fields were then analyzed using a pattern recognition algorithm which employed empirical orthogonal decomposition and cluster analysis. For every CT we conducted an analysis of their seasonal and interannual changes, along with their role in storm event formation. An increase of the storm CTs’ frequency in the second part of the 20th century was shown to be in a close agreement with teleconnection circulation patterns such as the Arctic Oscillation, North Atlantic Oscillation and the Scandinavian blocking.

The Non-Gaussianity and Spatial Asymmetry of Temperature Extremes Relative to the Storm Track: The Role of Horizontal Advection

2017 ◽  
Vol 30 (2) ◽  
pp. 445-464 ◽  
Author(s):  
Chaim I. Garfinkel ◽  
Nili Harnik
Keyword(s):  
General Circulation ◽  
Extreme Temperature ◽  
Storm Track ◽  
Reanalysis Data ◽  
Temperature Extremes ◽  
Tropospheric Temperature ◽  
Positive Temperature ◽  
The West ◽  
Near Surface ◽  
Temperature Advection

The distribution of near-surface and tropospheric temperature variability in midlatitudes is distinguishable from a Gaussian in meteorological reanalysis data; consistent with this, warm extremes occur preferentially poleward of the location of cold extremes. To understand the factors that drive this non-Gaussianity, a dry general circulation model and a simple model of Lagrangian temperature advection are used to investigate the connections between dynamical processes and the occurrence of extreme temperature events near the surface. The non-Gaussianity evident in reanalysis data is evident in the dry model experiments, and the location of extremes is influenced by the location of the jet stream and storm track. The cause of this in the model can be traced back to the synoptic evolution within the storm track leading up to cold and warm extreme events: negative temperature extremes occur when an equatorward propagating high–low couplet (high to the west) strongly advects isotherms equatorward over a large meridional fetch over more than two days. Positive temperature anomalies occur when a poleward propagating low–high couplet (low to the west) advects isotherms poleward over a large meridional fetch over more than two days. The magnitude of the extremes is enhanced by the meridional movement of the systems. Overall, horizontal temperature advection by storm track systems can account for the warm/cold asymmetry in the latitudinal distribution of the temperature extremes.

scholarly journals Cold-Season Tornadoes: Climatological and Meteorological Insights

2018 ◽  
Vol 33 (3) ◽  
pp. 671-691 ◽  
Author(s):  
Samuel J. Childs ◽  
Russ S. Schumacher ◽  
John T. Allen
Keyword(s):  
United States ◽  
Public Awareness ◽  
Warm Season ◽  
Cold Season ◽  
Reanalysis Data ◽  
The Arctic ◽  
Current State ◽  
The Arctic Oscillation ◽  
Bull's Eye ◽  
Convective Mode

Abstract Tornadoes that occur during the cold season, defined here as November–February (NDJF), pose many societal risks, yet less attention has been given to their climatological trends and variability than their warm-season counterparts, and their meteorological environments have been studied relatively recently. This study aims to advance the current state of knowledge of cold-season tornadoes through analysis of these components. A climatology of all (E)F1–(E)F5 NDJF tornadoes from 1953 to 2015 across a domain of 25°–42.5°N, 75°–100°W was developed. An increasing trend in cold-season tornado occurrence was found across much of the southeastern United States, with a bull’s-eye in western Tennessee, while a decreasing trend was found across eastern Oklahoma. Spectral analysis reveals a cyclic pattern of enhanced NDJF counts every 3–7 years, coincident with the period of ENSO. La Niña episodes favor enhanced NDJF counts, but a stronger relationship was found with the Arctic Oscillation (AO). From a meteorological standpoint, the most-tornadic and least-tornadic NDJF seasons were compared using NCEP–NCAR reanalysis data of various severe weather and tornado parameters. The most-tornadic cold seasons are characterized by warm and moist conditions across the Southeast, with an anomalous mean trough across the western United States. In addition, analysis of the convective mode reveals that NDJF tornadoes are common in both discrete and linear storm modes, yet those associated with discrete supercells are more deadly. Taken together, the perspectives presented here provide a deeper understanding of NDJF tornadoes and their societal impacts, an understanding that serves to increase public awareness and reduce human casualty.

scholarly journals Arctic-Mid-Latitude Linkages in a Nonlinear Quasi-Geostrophic Atmospheric Model

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Dörthe Handorf ◽  
Klaus Dethloff ◽  
Sabine Erxleben ◽  
Ralf Jaiser ◽  
Michael V. Kurgansky
Keyword(s):  
Sea Ice ◽  
Atmospheric Circulation ◽  
Large Scale ◽  
Atmospheric Model ◽  
Reanalysis Data ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Northern Eurasia ◽  
The Arctic Oscillation ◽  
The Impact

A quasi-geostrophic three-level T63 model of the wintertime atmospheric circulation of the Northern Hemisphere has been applied to investigate the impact of Arctic amplification (increase in surface air temperatures and loss of Arctic sea ice during the last 15 years) on the mid-latitude large-scale atmospheric circulation. The model demonstrates a mid-latitude response to an Arctic diabatic heating anomaly. A clear shift towards a negative phase of the Arctic Oscillation (AO−) during low sea-ice-cover conditions occurs, connected with weakening of mid-latitude westerlies over the Atlantic and colder winters over Northern Eurasia. Compared to reanalysis data, there is no clear model response with respect to the Pacific Ocean and North America.

scholarly journals The ground-based FTIR network's potential for investigating the atmospheric water cycle

2010 ◽  
Vol 10 (7) ◽  
pp. 3427-3442 ◽  
Author(s):  
M. Schneider ◽  
K. Yoshimura ◽  
F. Hase ◽  
T. Blumenstock
Keyword(s):  
General Circulation ◽  
Water Cycle ◽  
Circulation Model ◽  
Hadley Circulation ◽  
Reanalysis Data ◽  
The Arctic ◽  
Atmospheric Water ◽  
Arctic Oscillation Index ◽  
Northern Atlantic ◽  
The Arctic Oscillation

Abstract. We present tropospheric H216O and HD16O/H216O vapour profiles measured by ground-based FTIR (Fourier Transform Infrared) spectrometers between 1996 and 2008 at a northern hemispheric subarctic and subtropical site (Kiruna, Northern Sweden, 68° N and Izaña, Tenerife Island, 28° N, respectively). We compare these measurements to an isotope incorporated atmospheric general circulation model (AGCM). If the model is nudged towards meteorological fields of reanalysis data the agreement is very satisfactory on time scales ranging from daily to inter-annual. Taking the Izaña and Kiruna measurements as an example we document the FTIR network's unique potential for investigating the atmospheric water cycle. At the subarctic site we find strong correlations between the FTIR data, on the one hand, and the Arctic Oscillation index and the northern Atlantic sea surface temperature, on the other hand. The Izaña FTIR measurements reveal the importance of the Hadley circulation and the Northern Atlantic Oscillation index for the subtropical middle/upper tropospheric water balance. We document where the AGCM is able to capture these complexities of the water cycle and where it fails.

scholarly journals Analysis of Arctic Spring Ozone Anomaly in the Phases of QBO and 11-Year Solar Cycle for 1979–2017

Atmosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 582
Author(s):  
Yousuke Yamashita ◽  
Hideharu Akiyoshi ◽  
Masaaki Takahashi
Keyword(s):  
Solar Cycle ◽  
Climate Model ◽  
Polar Vortex ◽  
Reanalysis Data ◽  
Early Spring ◽  
The Arctic ◽  
Negative Anomaly ◽  
Late Winter ◽  
Quasi Biennial Oscillation ◽  
Biennial Oscillation

Arctic ozone amount in winter to spring shows large year-to-year variation. This study investigates Arctic spring ozone in relation to the phase of quasi-biennial oscillation (QBO)/the 11-year solar cycle, using satellite observations, reanalysis data, and outputs of a chemistry climate model (CCM) during the period of 1979–2017. For this duration, we found that the composite mean of the Northern Hemisphere high-latitude total ozone in the QBO-westerly (QBO-W)/solar minimum (Smin) phase is slightly smaller than those averaged for the QBO-W/Smax and QBO-E/Smax years in March. An analysis of a passive ozone tracer in the CCM simulation indicates that this negative anomaly is primarily caused by transport. The negative anomaly is consistent with a weakening of the residual mean downward motion in the polar lower stratosphere. The contribution of chemical processes estimated using the column amount difference between ozone and the passive ozone tracer is between 10–20% of the total anomaly in March. The lower ozone levels in the Arctic spring during the QBO-W/Smin years are associated with a stronger Arctic polar vortex from late winter to early spring, which is linked to the reduced occurrence of sudden stratospheric warming in the winter during the QBO-W/Smin years.

scholarly journals The Influence of Stratospheric Vortex Displacements and Splits on Surface Climate

2013 ◽  
Vol 26 (8) ◽  
pp. 2668-2682 ◽  
Author(s):  
Daniel M. Mitchell ◽  
Lesley J. Gray ◽  
James Anstey ◽  
Mark P. Baldwin ◽  
Andrew J. Charlton-Perez
Keyword(s):  
North America ◽  
Time Scales ◽  
Polar Vortex ◽  
Reanalysis Data ◽  
The Arctic ◽  
Positive Temperature ◽  
Cold Air ◽  
Weather Patterns ◽  
Northern Latitudes ◽  
Stratospheric Variability

Abstract A strong link exists between stratospheric variability and anomalous weather patterns at the earth’s surface. Specifically, during extreme variability of the Arctic polar vortex termed a “weak vortex event,” anomalies can descend from the upper stratosphere to the surface on time scales of weeks. Subsequently the outbreak of cold-air events have been noted in high northern latitudes, as well as a quadrupole pattern in surface temperature over the Atlantic and western European sectors, but it is currently not understood why certain events descend to the surface while others do not. This study compares a new classification technique of weak vortex events, based on the distribution of potential vorticity, with that of an existing technique and demonstrates that the subdivision of such events into vortex displacements and vortex splits has important implications for tropospheric weather patterns on weekly to monthly time scales. Using reanalysis data it is found that vortex splitting events are correlated with surface weather and lead to positive temperature anomalies over eastern North America of more than 1.5 K, and negative anomalies over Eurasia of up to −3 K. Associated with this is an increase in high-latitude blocking in both the Atlantic and Pacific sectors and a decrease in European blocking. The corresponding signals are weaker during displacement events, although ultimately they are shown to be related to cold-air outbreaks over North America. Because of the importance of stratosphere–troposphere coupling for seasonal climate predictability, identifying the type of stratospheric variability in order to capture the correct surface response will be necessary.

Do Changes in the Midlatitude Circulation Have Any Impact on the Arctic Surface Air Temperature Trend?

2006 ◽  
Vol 19 (20) ◽  
pp. 5422-5438 ◽  
Author(s):  
R. G. Graversen
Keyword(s):  
Air Temperature ◽  
Energy Transport ◽  
Surface Air Temperature ◽  
Arctic Region ◽  
Reanalysis Data ◽  
The Arctic ◽  
Positive Trend ◽  
Important Indicator ◽  
Near Surface ◽  
The Mean

Abstract The warming of the near-surface air in the Arctic region has been larger than the global mean surface warming. There is general agreement that the Arctic amplification of the surface air temperature (SAT) trend to a considerable extent is due to local effects such as the retreat of sea ice, especially during the summer months, and earlier melting of snow in the spring season. There is no doubt that these processes are important causes of the Arctic SAT trend. It is less clear, however, whether the trend may also be related to recent changes in the atmospheric midlatitude circulation. This question is the focus of the present paper. Model experiments have shown that in a warmer climate responding to, for example, a doubling of CO2, the atmospheric northward energy transport (ANET) will increase and cause polar SAT amplification. In the present study, the development of the ANET across 60°N and its linkage to the Arctic SAT have been explored using the ERA-40 reanalysis data from the European Centre for Medium-Range Weather Forecasts (ECMWF). It is found that during 1979–2001, the ANET has experienced an overall positive but weak trend, which was largest during the period from the mid-1980s to the mid-1990s. In addition, it is found that the Arctic SAT is sensitive to variability of the ANET across 60°N and hence to variability of the midlatitude circulation: A large ANET is followed by warming of the Arctic where ANET leads by about 5 days. The warming is located primarily north of the Atlantic and Pacific sectors, indicating that baroclinic weather systems developing around the Icelandic and Aleutian lows are important for the energy transport. Furthermore, it is suggested here that a small, but statistically significant, part of the mean Arctic SAT trend is linked to the trend in the ANET. Another important indicator of the midlatitude circulation is the Arctic Oscillation (AO). Through the 1980s and early 1990s the AO index has shown a positive trend. However, even though a part of the SAT trend can be related to the AO in localized parts of the Arctic area, the mean Arctic SAT trend shows no significant linkage to the AO.

Sign in / Sign up

Export Citation Format

Share Document