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57. How do intermittency and simultaneous processes obfuscate the Arctic influence on midlatitude winter extreme weather events?

Author

Overland, James E., Ballinger, Thomas J., Cohen, Judah, Francis, Jennifer, Hanna, Edward, Jaiser, Ralf, Kim, Baek-Min, Kim, Seong-Joong, Ukita, Jinro, Vihma, Timo, Wang, Muyin, Zhang, Xiangdong, Overland, James E., Ballinger, Thomas J., Cohen, Judah, Francis, Jennifer, Hanna, Edward, Jaiser, Ralf, Kim, Baek-Min, Kim, Seong-Joong, Ukita, Jinro, Vihma, Timo, Wang, Muyin, and Zhang, Xiangdong

Published
2021

58. The Arctic

Author

Sub Dynamics Meteorology, Proceskunde, Sub Algemeen Marine & Atmospheric Res, Marine and Atmospheric Research, Druckenmiller, Matthew L., Moon, Twila A., Thoman, Richard L., Ballinger, Thomas J., Berner, Logan T., Bernhard, Germar H., Bhatt, Uma S., Bjerke, Jarle W., Box, Jason E., Brown, R., Cappelen, John, Christiansen, Hanne H., Decharme, B., Derksen, C., Divine, Dmitry, Drozdov, D. S., Elias Chereque, A., Epstein, Howard E., Farquharson, L. M., Farrell, Sinead L., Fausto, Robert S., Fettweis, Xavier, Fioletov, Vitali E., Forbes, Bruce C., Frost, Gerald V., Gargulinski, Emily, Gerland, Sebastian, Goetz, Scott J., Grabinski, Z., Grooß, Jens-Uwe, Haas, Christian, Hanna, Edward, Hanssen-Bauer, Inger, Hendricks, Stefan, Holmes, Robert M., Ialongo, Iolanda, Isaksen, K., Jain, Piyush, Johnsen, Bjørn, Kaleschke, L., Kholodov, A. L., Kim, Seong-Joong, Korsgaard, Niels J., Labe, Zachary, Lakkala, Kaisa, Lara, Mark J., Loomis, Bryant, Luojus, K., Macander, Matthew J., Malkova, G. V., Mankoff, Kenneth D., Manney, Gloria L., McClelland, James W., Meier, Walter N., Mote, Thomas, Mudryk, L., Müller, Rolf, Nyland, K. E., Overland, James E., Park, T., Pavlova, Olga, Perovich, Don, Petty, Alek, Phoenix, Gareth K., Raynolds, Martha K., Reijmer, C. H., Richter-Menge, Jacqueline, Ricker, Robert, Romanovsky, Vladimir E., Scott, Lindsay, Shapiro, Hazel, Shiklomanov, Alexander I., Shiklomanov, Nikolai I., Smeets, C. J. P. P., Smith, Sharon L., Soja, Amber, Spencer, Robert G. M., Starkweather, Sandy, Streletskiy, Dimitri A., Suslova, Anya, Svendby, Tove, Tank, Suzanne E., Tedesco, Marco, Tian-Kunze, X., Timmermans, Mary-Louise, Tømmervik, Hans, Tretiakov, Mikhail, Tschudi, Mark, Vakhutinsky, Sofia, van As, Dirk, van de Wal, R. S. W., Veraverbeke, Sander, Walker, Donald A., Walsh, John E., Wang, Muyin, Webster, Melinda, Winton, Øyvind, Wood, K., York, Alison, Ziel, Robert, Sub Dynamics Meteorology, Proceskunde, Sub Algemeen Marine & Atmospheric Res, Marine and Atmospheric Research, Druckenmiller, Matthew L., Moon, Twila A., Thoman, Richard L., Ballinger, Thomas J., Berner, Logan T., Bernhard, Germar H., Bhatt, Uma S., Bjerke, Jarle W., Box, Jason E., Brown, R., Cappelen, John, Christiansen, Hanne H., Decharme, B., Derksen, C., Divine, Dmitry, Drozdov, D. S., Elias Chereque, A., Epstein, Howard E., Farquharson, L. M., Farrell, Sinead L., Fausto, Robert S., Fettweis, Xavier, Fioletov, Vitali E., Forbes, Bruce C., Frost, Gerald V., Gargulinski, Emily, Gerland, Sebastian, Goetz, Scott J., Grabinski, Z., Grooß, Jens-Uwe, Haas, Christian, Hanna, Edward, Hanssen-Bauer, Inger, Hendricks, Stefan, Holmes, Robert M., Ialongo, Iolanda, Isaksen, K., Jain, Piyush, Johnsen, Bjørn, Kaleschke, L., Kholodov, A. L., Kim, Seong-Joong, Korsgaard, Niels J., Labe, Zachary, Lakkala, Kaisa, Lara, Mark J., Loomis, Bryant, Luojus, K., Macander, Matthew J., Malkova, G. V., Mankoff, Kenneth D., Manney, Gloria L., McClelland, James W., Meier, Walter N., Mote, Thomas, Mudryk, L., Müller, Rolf, Nyland, K. E., Overland, James E., Park, T., Pavlova, Olga, Perovich, Don, Petty, Alek, Phoenix, Gareth K., Raynolds, Martha K., Reijmer, C. H., Richter-Menge, Jacqueline, Ricker, Robert, Romanovsky, Vladimir E., Scott, Lindsay, Shapiro, Hazel, Shiklomanov, Alexander I., Shiklomanov, Nikolai I., Smeets, C. J. P. P., Smith, Sharon L., Soja, Amber, Spencer, Robert G. M., Starkweather, Sandy, Streletskiy, Dimitri A., Suslova, Anya, Svendby, Tove, Tank, Suzanne E., Tedesco, Marco, Tian-Kunze, X., Timmermans, Mary-Louise, Tømmervik, Hans, Tretiakov, Mikhail, Tschudi, Mark, Vakhutinsky, Sofia, van As, Dirk, van de Wal, R. S. W., Veraverbeke, Sander, Walker, Donald A., Walsh, John E., Wang, Muyin, Webster, Melinda, Winton, Øyvind, Wood, K., York, Alison, and Ziel, Robert

Published
2021

63. The Arctic

Author

Andersen, J K, Andreassen, Liss M, Baker, Emily H, Ballinger, Thomas J, Berner, Logan T, Bernhard, Germar H, Bhatt, Uma S, Bjerke, Jarle W, Box, Jason E, Britt, L, Brown, R, Burgess, David, Cappelen, John, Christiansen, Hanne H, Decharme, B, Derksen, C, Drozdov, D S, Epstein, Howard E, Farquharson, L M, Farrell, Sinead L, Fausto, Robert S, Fettweis, Xavier, Fioletov, Vitali E, Forbes, Bruce C, Frost, Gerald V, Gerland, Sebastian, Goetz, Scott J, Grooß, Jens-Uwe, Hanna, Edward, Hanssen-Bauer, Inger, Hendricks, Stefan, Ialongo, Iolanda, Isaksen, K, Johnsen, Bjørn, Kaleschke, L, Kholodov, A L, Kim, Seong-Joong, Kohler, Jack, Labe, Zachary, Ladd, Carol, Lakkala, Kaisa, Lara, Mark J, Loomis Bryant andLuks, Bartlomiej, Luojus, K, Macander, Matthew J, Malkova, G V, Mankoff, Kenneth D, Manney, Gloria L, Marsh, J M, Meier, Walt, Moon, Twila A, Mote, Thomas, Mudryk, L, Mueter, F J, Müller, Rolf, Nyland, K E, O'Neel, Shad, Overland, James E, Perovich, Don, Phoenix, Gareth K, Raynolds, Martha K, Reijmer, C H, Ricker, Robert, Romanovsky, Vladimir E, Schuur, E A G, Sharp, Martin, Shiklomanov, Nikolai I, Smeets, C J P P, Smith, Sharon L, Streletskiy, Dimitri A, Tedesco, Marco, Thoman, Richard L, Thorson, J T, Tian-Kunze, X, Timmermans, Mary-Louise, Tømmervik, Hans, Tschudi, Mark, van As, Dirk, van de Wal, R S W, Walker, Donald A, Walsh, John E, Wang, Muyin, Webster, Melinda, Winton, Øyvind, Wolken, Gabriel J, Wood, K, Wouters, Bert, Zador, S, Richter-Menge, Jacqueline, Druckenmiller, Matthew L, Andersen, J K, Andreassen, Liss M, Baker, Emily H, Ballinger, Thomas J, Berner, Logan T, Bernhard, Germar H, Bhatt, Uma S, Bjerke, Jarle W, Box, Jason E, Britt, L, Brown, R, Burgess, David, Cappelen, John, Christiansen, Hanne H, Decharme, B, Derksen, C, Drozdov, D S, Epstein, Howard E, Farquharson, L M, Farrell, Sinead L, Fausto, Robert S, Fettweis, Xavier, Fioletov, Vitali E, Forbes, Bruce C, Frost, Gerald V, Gerland, Sebastian, Goetz, Scott J, Grooß, Jens-Uwe, Hanna, Edward, Hanssen-Bauer, Inger, Hendricks, Stefan, Ialongo, Iolanda, Isaksen, K, Johnsen, Bjørn, Kaleschke, L, Kholodov, A L, Kim, Seong-Joong, Kohler, Jack, Labe, Zachary, Ladd, Carol, Lakkala, Kaisa, Lara, Mark J, Loomis Bryant andLuks, Bartlomiej, Luojus, K, Macander, Matthew J, Malkova, G V, Mankoff, Kenneth D, Manney, Gloria L, Marsh, J M, Meier, Walt, Moon, Twila A, Mote, Thomas, Mudryk, L, Mueter, F J, Müller, Rolf, Nyland, K E, O'Neel, Shad, Overland, James E, Perovich, Don, Phoenix, Gareth K, Raynolds, Martha K, Reijmer, C H, Ricker, Robert, Romanovsky, Vladimir E, Schuur, E A G, Sharp, Martin, Shiklomanov, Nikolai I, Smeets, C J P P, Smith, Sharon L, Streletskiy, Dimitri A, Tedesco, Marco, Thoman, Richard L, Thorson, J T, Tian-Kunze, X, Timmermans, Mary-Louise, Tømmervik, Hans, Tschudi, Mark, van As, Dirk, van de Wal, R S W, Walker, Donald A, Walsh, John E, Wang, Muyin, Webster, Melinda, Winton, Øyvind, Wolken, Gabriel J, Wood, K, Wouters, Bert, Zador, S, Richter-Menge, Jacqueline, and Druckenmiller, Matthew L

Published
2020

64. The Arctic

Author

Dep Natuurkunde, Sub Dynamics Meteorology, Proceskunde, Sub Algemeen Marine & Atmospheric Res, Marine and Atmospheric Research, Andersen, J K, Andreassen, Liss M, Baker, Emily H, Ballinger, Thomas J, Berner, Logan T, Bernhard, Germar H, Bhatt, Uma S, Bjerke, Jarle W, Box, Jason E, Britt, L, Brown, R, Burgess, David, Cappelen, John, Christiansen, Hanne H, Decharme, B, Derksen, C, Drozdov, D S, Epstein, Howard E, Farquharson, L M, Farrell, Sinead L, Fausto, Robert S, Fettweis, Xavier, Fioletov, Vitali E, Forbes, Bruce C, Frost, Gerald V, Gerland, Sebastian, Goetz, Scott J, Grooß, Jens-Uwe, Hanna, Edward, Hanssen-Bauer, Inger, Hendricks, Stefan, Ialongo, Iolanda, Isaksen, K, Johnsen, Bjørn, Kaleschke, L, Kholodov, A L, Kim, Seong-Joong, Kohler, Jack, Labe, Zachary, Ladd, Carol, Lakkala, Kaisa, Lara, Mark J, Loomis Bryant andLuks, Bartlomiej, Luojus, K, Macander, Matthew J, Malkova, G V, Mankoff, Kenneth D, Manney, Gloria L, Marsh, J M, Meier, Walt, Moon, Twila A, Mote, Thomas, Mudryk, L, Mueter, F J, Müller, Rolf, Nyland, K E, O'Neel, Shad, Overland, James E, Perovich, Don, Phoenix, Gareth K, Raynolds, Martha K, Reijmer, C H, Ricker, Robert, Romanovsky, Vladimir E, Schuur, E A G, Sharp, Martin, Shiklomanov, Nikolai I, Smeets, C J P P, Smith, Sharon L, Streletskiy, Dimitri A, Tedesco, Marco, Thoman, Richard L, Thorson, J T, Tian-Kunze, X, Timmermans, Mary-Louise, Tømmervik, Hans, Tschudi, Mark, van As, Dirk, van de Wal, R S W, Walker, Donald A, Walsh, John E, Wang, Muyin, Webster, Melinda, Winton, Øyvind, Wolken, Gabriel J, Wood, K, Wouters, Bert, Zador, S, Richter-Menge, Jacqueline, Druckenmiller, Matthew L, Dep Natuurkunde, Sub Dynamics Meteorology, Proceskunde, Sub Algemeen Marine & Atmospheric Res, Marine and Atmospheric Research, Andersen, J K, Andreassen, Liss M, Baker, Emily H, Ballinger, Thomas J, Berner, Logan T, Bernhard, Germar H, Bhatt, Uma S, Bjerke, Jarle W, Box, Jason E, Britt, L, Brown, R, Burgess, David, Cappelen, John, Christiansen, Hanne H, Decharme, B, Derksen, C, Drozdov, D S, Epstein, Howard E, Farquharson, L M, Farrell, Sinead L, Fausto, Robert S, Fettweis, Xavier, Fioletov, Vitali E, Forbes, Bruce C, Frost, Gerald V, Gerland, Sebastian, Goetz, Scott J, Grooß, Jens-Uwe, Hanna, Edward, Hanssen-Bauer, Inger, Hendricks, Stefan, Ialongo, Iolanda, Isaksen, K, Johnsen, Bjørn, Kaleschke, L, Kholodov, A L, Kim, Seong-Joong, Kohler, Jack, Labe, Zachary, Ladd, Carol, Lakkala, Kaisa, Lara, Mark J, Loomis Bryant andLuks, Bartlomiej, Luojus, K, Macander, Matthew J, Malkova, G V, Mankoff, Kenneth D, Manney, Gloria L, Marsh, J M, Meier, Walt, Moon, Twila A, Mote, Thomas, Mudryk, L, Mueter, F J, Müller, Rolf, Nyland, K E, O'Neel, Shad, Overland, James E, Perovich, Don, Phoenix, Gareth K, Raynolds, Martha K, Reijmer, C H, Ricker, Robert, Romanovsky, Vladimir E, Schuur, E A G, Sharp, Martin, Shiklomanov, Nikolai I, Smeets, C J P P, Smith, Sharon L, Streletskiy, Dimitri A, Tedesco, Marco, Thoman, Richard L, Thorson, J T, Tian-Kunze, X, Timmermans, Mary-Louise, Tømmervik, Hans, Tschudi, Mark, van As, Dirk, van de Wal, R S W, Walker, Donald A, Walsh, John E, Wang, Muyin, Webster, Melinda, Winton, Øyvind, Wolken, Gabriel J, Wood, K, Wouters, Bert, Zador, S, Richter-Menge, Jacqueline, and Druckenmiller, Matthew L

Published
2020

67. Regime shifts and red noise in the North Pacific

Author

Overland, James E., Percival, Donald B., and Mofjeld, Harold O.

Subjects
Climate cycles -- Analysis, Earth sciences
Abstract

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.dsr.2005.12.011 Byline: James E. Overland (a), Donald B. Percival (b), Harold O. Mofjeld (a) Abstract: Regimes and regime shifts are important concepts for understanding decadal variability in the physical system of the North Pacific because of the potential for an ecosystem to reorganize itself in response to such shifts. There are two prevalent senses in which these concepts are taken in the literature. The first is a formal definition and posits multiple stable states and rapid transitions between these states. The second is more data-oriented and identifies local regimes based on differing average climatic levels over a multi-annual duration, i.e. simply interdecadal fluctuations. This second definition is consistent with realizations from stochastic red noise processes to a degree that depends upon the particular model. Even in 100 year long records for the North Pacific a definition of regimes based solely on distinct multiple stable states is difficult to prove or disprove, while on interdecadal scales there are apparent local step-like features and multi-year intervals where the state remains consistently above or below the long-term mean. The terminologies climatic regime shift, statistical regime shift or climatic event are useful for distinguishing this second definition from the first. To illustrate the difficulty of advocating one definition over the other based upon a relatively short time series, we compare three simple models for the Pacific Decadal Oscillation (PDO). The 104-year PDO record is insufficient to statistically distinguish a single preference between a square wave oscillator consistent with the formal definition for regime shifts, and two red noise models that are compatible with climatic regime shifts. Because of the inability to distinguish between underlying processes based upon data, it is necessary to entertain multiple models and to consider how each model would impact resource management. In particular the persistence in the fitted models implies that certain probabilistic statements can be made regarding climatic regime shifts, but we caution against extrapolation to future states based on curve fitting techniques. Author Affiliation: (a) NOAA/Pacific Marine Environmental Laboratory, 7600 Sand Point Way NE, Seattle, WA 98115-6349, USA (b) Applied Physics Laboratory/University of Washington, Seattle, WA 98195, USA Article History: Received 15 December 2004; Revised 6 July 2005; Accepted 21 December 2005

Published
2006

75. The Arctic

Author

Andersen, J. K., additional, Andreassen, Liss M., additional, Baker, Emily H., additional, Ballinger, Thomas J., additional, Berner, Logan T., additional, Bernhard, Germar H., additional, Bhatt, Uma S., additional, Bjerke, Jarle W., additional, Box, Jason E., additional, Britt, L., additional, Brown, R., additional, Burgess, David, additional, Cappelen, John, additional, Christiansen, Hanne H., additional, Decharme, B., additional, Derksen, C., additional, Drozdov, D. S., additional, Epstein, Howard E., additional, Farquharson, L. M., additional, Farrell, Sinead L., additional, Fausto, Robert S., additional, Fettweis, Xavier, additional, Fioletov, Vitali E., additional, Forbes, Bruce C., additional, Frost, Gerald V., additional, Gerland, Sebastian, additional, Goetz, Scott J., additional, Grooß, Jens-Uwe, additional, Hanna, Edward, additional, Hanssen-Bauer, Inger, additional, Hendricks, Stefan, additional, Ialongo, Iolanda, additional, Isaksen, K., additional, Johnsen, Bjørn, additional, Kaleschke, L., additional, Kholodov, A. L., additional, Kim, Seong-Joong, additional, Kohler, Jack, additional, Labe, Zachary, additional, Ladd, Carol, additional, Lakkala, Kaisa, additional, Lara, Mark J., additional, Loomis, Bryant, additional, Luks, Bartłomiej, additional, Luojus, K., additional, Macander, Matthew J., additional, Malkova, G. V., additional, Mankoff, Kenneth D., additional, Manney, Gloria L., additional, Marsh, J. M., additional, Meier, Walt, additional, Moon, Twila A., additional, Mote, Thomas, additional, Mudryk, L., additional, Mueter, F. J., additional, Müller, Rolf, additional, Nyland, K. E., additional, O’Neel, Shad, additional, Overland, James E., additional, Perovich, Don, additional, Phoenix, Gareth K., additional, Raynolds, Martha K., additional, Reijmer, C. H., additional, Ricker, Robert, additional, Romanovsky, Vladimir E., additional, Schuur, E. A. G., additional, Sharp, Martin, additional, Shiklomanov, Nikolai I., additional, Smeets, C. J. P. P., additional, Smith, Sharon L., additional, Streletskiy, Dimitri A., additional, Tedesco, Marco, additional, Thoman, Richard L., additional, Thorson, J. T., additional, Tian-Kunze, X., additional, Timmermans, Mary-Louise, additional, Tømmervik, Hans, additional, Tschudi, Mark, additional, van As, Dirk, additional, van de Wal, R. S. W., additional, Walker, Donald A., additional, Walsh, John E., additional, Wang, Muyin, additional, Webster, Melinda, additional, Winton, Øyvind, additional, Wolken, Gabriel J., additional, Wood, K., additional, Wouters, Bert, additional, and Zador, S., additional

Published
2020
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78. Key indicators of Arctic climate change: 1971–2017

Author

Box, Jason E., Colgan, William T., Christensen, Torben Røjle, Schmidt, Niels Martin, Lund, Magnus, Parmentier, Frans-Jan W., Brown, Ross, Bhatt, Uma S., Euskirchen, Eugénie S., Romanovsky, Vladimir E., Walsh, John E., Overland, James E., Wang, Muyin, Corell, Robert W., Meier, Walter N., Wouters, Bert, Mernild, Sebastian, ard, Johanna Mtextbackslasha, Pawlak, Janet, Olsen, Morten Skovgtextbackslasha ard, Box, Jason E., Colgan, William T., Christensen, Torben Røjle, Schmidt, Niels Martin, Lund, Magnus, Parmentier, Frans-Jan W., Brown, Ross, Bhatt, Uma S., Euskirchen, Eugénie S., Romanovsky, Vladimir E., Walsh, John E., Overland, James E., Wang, Muyin, Corell, Robert W., Meier, Walter N., Wouters, Bert, Mernild, Sebastian, ard, Johanna Mtextbackslasha, Pawlak, Janet, and Olsen, Morten Skovgtextbackslasha ard

Abstract

Key observational indicators of climate change in the Arctic, most spanning a 47 year period (1971–2017) demonstrate fundamental changes among nine key elements of the Arctic system. We find that, coherent with increasing air temperature, there is an intensification of the hydrological cycle, evident from increases in humidity, precipitation, river discharge, glacier equilibrium line altitude and land ice wastage. Downward trends continue in sea ice thickness (and extent) and spring snow cover extent and duration, while near-surface permafrost continues to warm. Several of the climate indicators exhibit a significant statistical correlation with air temperature or precipitation, reinforcing the notion that increasing air temperatures and precipitation are drivers of major changes in various components of the Arctic system. To progress beyond a presentation of the Arctic physical climate changes, we find a correspondence between air temperature and biophysical indicators such as tundra biomass and identify numerous biophysical disruptions with cascading effects throughout the trophic levels. These include: increased delivery of organic matter and nutrients to Arctic near‐coastal zones; condensed flowering and pollination plant species periods; timing mismatch between plant flowering and pollinators; increased plant vulnerability to insect disturbance; increased shrub biomass; increased ignition of wildfires; increased growing season CO2 uptake, with counterbalancing increases in shoulder season and winter CO2 emissions; increased carbon cycling, regulated by local hydrology and permafrost thaw; conversion between terrestrial and aquatic ecosystems; and shifting animal distribution and demographics. The Arctic biophysical system is now clearly trending away from its 20th Century state and into an unprecedented state, with implications not only within but beyond the Arctic. The indicator time series of this study are freely downloadable at AMAP.no.

Published
2019

79. Key indicators of Arctic climate change: 1971–2017

Author

Sub Dynamics Meteorology, Marine and Atmospheric Research, Box, Jason E., Colgan, William T., Christensen, Torben Røjle, Schmidt, Niels Martin, Lund, Magnus, Parmentier, Frans-Jan W., Brown, Ross, Bhatt, Uma S., Euskirchen, Eugénie S., Romanovsky, Vladimir E., Walsh, John E., Overland, James E., Wang, Muyin, Corell, Robert W., Meier, Walter N., Wouters, Bert, Mernild, Sebastian, ard, Johanna Mtextbackslasha, Pawlak, Janet, Olsen, Morten Skovgtextbackslasha ard, Sub Dynamics Meteorology, Marine and Atmospheric Research, Box, Jason E., Colgan, William T., Christensen, Torben Røjle, Schmidt, Niels Martin, Lund, Magnus, Parmentier, Frans-Jan W., Brown, Ross, Bhatt, Uma S., Euskirchen, Eugénie S., Romanovsky, Vladimir E., Walsh, John E., Overland, James E., Wang, Muyin, Corell, Robert W., Meier, Walter N., Wouters, Bert, Mernild, Sebastian, ard, Johanna Mtextbackslasha, Pawlak, Janet, and Olsen, Morten Skovgtextbackslasha ard

Published
2019

80. Atmospheric Pressure Rivalry Between the Arctic and Northern Pacific: Implications for Alaskan Climate Variability.

Author

Polyakov, Igor V., Ballinger, Thomas J., Overland, James E., Vavrus, Stephen J., Danielson, Seth L., Lader, Rick, Bhatt, Uma S., Hendricks, Amy S., and Mueter, Franz J.

Subjects
*POLYWATER, *ARCTIC climate, *SEA ice, *ENTHALPY, *WATER masses
Abstract

ABSTRACT Located at the confluence of the Arctic and North Pacific and with Alaska at its heart, the Pacific Arctic Region (PAR) is a unique and interconnected regional climate system. Significant climatic changes in the PAR are described by a novel, mobile monthly Alaska Arctic Front (AAF) index, which is defined by sea level pressure differences between the migratory cores of the Beaufort High and Aleutian Low. Regional climate variability associated with the AAF shows prominent decadal signatures that are driven by the opposing effects of the North Pacific and the Arctic atmospheric pressure fields. Low AAF (negative phase) is dominated by North Pacific forcing, whereas high AAF (positive phase) is dominated by Arctic atmospheric processes. The recent (2011–2021) negative AAF phase, which is associated with the westward displacement of Aleutian Low explaining stronger northward winds and enhanced water transport northward through Bering Strait, is conducive to increased oceanic heat and freshwater content, reduced regional sea ice cover in the PAR, and to the expansion of Pacific species into the Arctic. These factors are all indicators of the Pacification of the Arctic Ocean, a key feature of climate change related to progression of anomalous Pacific water masses and biota into the polar basins. It is not yet clear if or when the recent phase of decadal variability will change and alter the rate of Pacification of the Arctic climate system. [ABSTRACT FROM AUTHOR]

Published
2024
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82. Effects of the tropospheric large‐scale circulation on European winter temperatures during the period of amplified Arctic warming

Author

Vihma, Timo, primary, Graversen, Rune, additional, Chen, Linling, additional, Handorf, Dörthe, additional, Skific, Natasa, additional, Francis, Jennifer A., additional, Tyrrell, Nicholas, additional, Hall, Richard, additional, Hanna, Edward, additional, Uotila, Petteri, additional, Dethloff, Klaus, additional, Karpechko, Alexey Y., additional, Björnsson, Halldor, additional, and Overland, James E., additional

Published
2019
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84. Key indicators of Arctic climate change: 1971–2017

Author

Box, Jason E, primary, Colgan, William T, additional, Christensen, Torben Røjle, additional, Schmidt, Niels Martin, additional, Lund, Magnus, additional, Parmentier, Frans-Jan W, additional, Brown, Ross, additional, Bhatt, Uma S, additional, Euskirchen, Eugénie S, additional, Romanovsky, Vladimir E, additional, Walsh, John E, additional, Overland, James E, additional, Wang, Muyin, additional, Corell, Robert W, additional, Meier, Walter N, additional, Wouters, Bert, additional, Mernild, Sebastian, additional, Mård, Johanna, additional, Pawlak, Janet, additional, and Olsen, Morten Skovgård, additional

Published
2019
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86. The 2020 Siberian heat wave.

Author

Overland, James E. and Wang, Muyin

Subjects
*HEAT waves (Meteorology), *JET streams, *POLAR vortex, *ARCTIC oscillation, *GEOPOTENTIAL height, *ZONAL winds
Abstract

Siberia saw a heat wave of extreme monthly temperatures of +6°C anomalies from January through May 2020, culminating with near daily temperature records at the Arctic station of Verhojansk in mid‐June. This was a major Arctic event. The proximate cause for the warm extremes from January through April was the record strength of the stratospheric polar vortex (SPV) and tropospheric jet stream. The SPV and high geopotential heights to the south combined to provide strong zonal winds from the west that reduced the potential penetration of cold air from the north. An index of vortex strength is the Arctic Oscillation (AO); averaged over January–April, the AO set extreme positive records in 1989, 1990, and 2020 (baseline starting in 1950). The strength and stability of the SPV over the central Arctic contributed to the winter–spring persistence of the heat wave in Siberia. May–June temperatures were related to high tropospheric geopotential heights over Asia. An open question is whether these dynamic events are becoming more persistent. Such record events will not occur every year but one can expect that they will occasionally naturally reoccur over the next decades due to internal atmospheric variability in addition to a continued global warming background. [ABSTRACT FROM AUTHOR]

Published
2021
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87. Effects of the tropospheric large‐scale circulation on European winter temperatures during the period of amplified Arctic warming.

Author

Vihma, Timo, Graversen, Rune, Chen, Linling, Handorf, Dörthe, Skific, Natasa, Francis, Jennifer A., Tyrrell, Nicholas, Hall, Richard, Hanna, Edward, Uotila, Petteri, Dethloff, Klaus, Karpechko, Alexey Y., Björnsson, Halldor, and Overland, James E.

Subjects
TROPOSPHERIC circulation, AIR masses, NORTH Atlantic oscillation, ATMOSPHERIC temperature, LATENT heat, TROPOSPHERIC ozone, TEMPERATURE
Abstract

We investigate factors influencing European winter (DJFM) air temperatures for the period 1979–2015 with the focus on changes during the recent period of rapid Arctic warming (1998–2015). We employ meteorological reanalyses analysed with a combination of correlation analysis, two pattern clustering techniques, and back‐trajectory airmass identification. In all five selected European regions, severe cold winter events lasting at least 4 days are significantly correlated with warm Arctic episodes. Relationships during opposite conditions of warm Europe/cold Arctic are also significant. Correlations have become consistently stronger since 1998. Large‐scale pattern analysis reveals that cold spells are associated with the negative phase of the North Atlantic Oscillation (NAO‐) and the positive phase of the Scandinavian (SCA+) pattern, which in turn are correlated with the divergence of dry‐static energy transport. Warm European extremes are associated with opposite phases of these patterns and the convergence of latent heat transport. Airmass trajectory analysis is consistent with these findings, as airmasses associated with extreme cold events typically originate over continents, while warm events tend to occur with prevailing maritime airmasses. Despite Arctic‐wide warming, significant cooling has occurred in northeastern Europe owing to a decrease in adiabatic subsidence heating in airmasses arriving from the southeast, along with increased occurrence of circulation patterns favouring low temperature advection. These dynamic effects dominated over the increased mean temperature of most circulation patterns. Lagged correlation analysis reveals that SCA‐ and NAO+ are typically preceded by cold Arctic anomalies during the previous 2–3 months, which may aid seasonal forecasting. [ABSTRACT FROM AUTHOR]

Published
2020
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