Blar i Geophysical Institute på forfatter "Keenlyside, Noel"
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Amplification of synoptic to annual variability of West African summer monsoon rainfall under global warming
Akinsanola, Akintomide Afolayan; Zhou, Wen; Zhou, Tianjun; Keenlyside, Noel (Journal article; Peer reviewed, 2020)Increased knowledge of future changes in rainfall variability is needed to reduce vulnerability to potential impacts of global warming, especially in highly vulnerable regions like West Africa. While changes in mean and ... -
Arctic sea ice and Eurasian climate: A review
Gao, Yongqi; Sun, Jianqi; Li, Fei; He, Shengping; Sandven, Stein; Yan, Qing; Zhang, Zhongshi; Lohmann, Katja; Keenlyside, Noel; Furevik, Tore; Suo, Lingling (Peer reviewed; Journal article, 2014-11-28)The Arctic plays a fundamental role in the climate system and has shown significant climate change in recent decades, including the Arctic warming and decline of Arctic sea-ice extent and thickness. In contrast to the ... -
The Arctic sea ice extent change connected to Pacific decadal variability
Yang, Xiao-Ying; Wang, Guihua; Keenlyside, Noel (Journal article; Peer reviewed, 2020)After an unprecedented retreat, the total Arctic sea ice cover for the post-2007 period is characterized by low extent and a remarkable increase in annual cycle amplitude. We have identified the leading role of spring ... -
An Atlantic-driven rapid circulation change in the North Pacific Ocean during the late 1990s
Wu, Chau-Ron; Lin, Yong-Fu; Wang, You-Lin; Keenlyside, Noel; Yu, Jin-Yi (Peer reviewed; Journal article, 2019-10-08)Interbasin interactions have been increasingly emphasized in recent years due to their roles in shaping climate trends and the global warming hiatus in the northern hemisphere. The profound influence from the North Atlantic ... -
Atmospheric signature of the Agulhas current
Nkwinkwa Njouodo, Arielle Stela; Koseki, Shunya; Keenlyside, Noel; Rouault, Mathieu (Journal article; Peer reviewed, 2018)Western boundary currents play an important role in the climate system by transporting heat poleward and releasing it to the atmosphere. While their influence on extratropical storms and oceanic rainfall is becoming ... -
Basin Interactions and predictability
Keenlyside, Noel; Kosaka, Yu; Vigaud, Nicholas; Robertson, Andrew; Wang, Yiguo; Dommenget, Dietmar; Luo, Jing-Jia; Matei, Daniela (Chapter, 2020) -
Causes of the large warm bias in the Angola–Benguela Frontal Zone in the Norwegian Earth System Model
Koseki, Shunya; Keenlyside, Noel; Demissie, Teferi Dejene; Toniazzo, Thomas; Counillon, Francois; Bethke, Ingo; Ilicak, Mehmet; Shen, Mao-Lin (Journal article; Peer reviewed, 2018)We have investigated the causes of the sea surface temperature (SST) bias in the Angola–Benguela Frontal Zone (ABFZ) of the southeastern Atlantic Ocean simulated by the Norwegian Earth System Model (NorESM). Similar to ... -
Climate based multi-year predictions of the Barents Sea cod stock.
Årthun, Marius; Bogstad, Bjarte; Daewel, Ute; Keenlyside, Noel; Sandø, Anne Britt; Schrum, Corinna; Ottersen, Geir (Peer reviewed; Journal article, 2018-10-24)Predicting fish stock variations on interannual to decadal time scales is one of the major issues in fisheries science and management. Although the field of marine ecological predictions is still in its infancy, it is ... -
Decadal prediction of Sahel rainfall: where does the skill (or lack thereof) come from?
Mohino, Elsa; Keenlyside, Noel; Pohlmann, Holger (Peer reviewed; Journal article, 2016-12)Previous works suggest decadal predictions of Sahel rainfall could be skillful. However, the sources of such skill are still under debate. In addition, previous results are based on short validation periods (i.e. less than ... -
Diabatic heating governs the seasonality of the Atlantic Niño
Nnamchi, Hyacinth C; Latif, Mojib; Keenlyside, Noel; Kjellsson, Joakim; Richter, Ingo (Journal article; Peer reviewed, 2021)The Atlantic Niño is the leading mode of interannual sea-surface temperature (SST) variability in the equatorial Atlantic and assumed to be largely governed by coupled ocean-atmosphere dynamics described by the Bjerknes-feedback ... -
The Dominant Patterns of Intraseasonal Rainfall Variability in May–October and November–April over the Tropical Western Pacific
Pariyar, Sunil Kumar; Keenlyside, Noel; Bhatt, Bhuwan Chandra; Omrani, Nour-Eddine (Journal article, 2019)The space–time structure of intraseasonal (10–90 day) rainfall variability in the western tropical Pacific is studied using daily 3B42 TRMM and ERA-Interim reanalysis data for the period 1998–2014. Empirical orthogonal ... -
Dynamically combining climate models to "supermodel" the tropical Pacific
Shen, Mao-Lin; Keenlyside, Noel; Selten, Frank; Wiegerinck, Wim; Duane, Gregory (Peer reviewed; Journal article, 2016-01)We construct an interactive ensemble of two different climate models to improve simulation of key aspects of tropical Pacific climate. Our so-called supermodel is based on two atmospheric general circulation models (AGCMs) ... -
Eastern boundary circulation and hydrography off Angola. Building Angolan oceanographic capacities
Tchipalanga, Pedro C.M.; Dengler, Marcus; Brandt, Peter; Kopte, Robert; Macuéria, Marisa; Coelho, Paulo; Ostrowski, Marek; Keenlyside, Noel (Peer reviewed; Journal article, 2018-09-06)The eastern boundary region off Angola encompasses a highly productive ecosystem important for the food security of the coastal population. The fish-stock distribution, however, undergoes large variability on intraseasonal, ... -
The El Niño effect on Ethiopian summer rainfall
Gleixner, Stephanie Nikola; Keenlyside, Noel; Viste, Ellen; Korecha, Diriba (Journal article; Peer reviewed, 2017)While El Niño is known to cause failure of Kiremt (boreal summer) rainfall in Ethiopia, the mechanisms are not fully understood. Here we use the ECHAM5 Atmospheric General Circulation Model to investigate the physical link ... -
An Equatorial–Extratropical Dipole Structure of the Atlantic Niño
Nnamchi, Hyacinth C; Li, Jianping; Kucharski, Fred; Kang, In-Sik; Keenlyside, Noel; Chang, Ping; Farneti, Riccardo (Peer reviewed; Journal article, 2016)Equatorial Atlantic variability is dominated by the Atlantic Niño peaking during the boreal summer. Studies have shown robust links of the Atlantic Niño to fluctuations of the St. Helena subtropical anticyclone and Benguela ... -
Evaluating Impacts of Recent Arctic Sea Ice Loss on the Northern Hemisphere Winter Climate Change
Ogawa, Fumiaki; Keenlyside, Noel; Gao, Yongqi; Koenigk, Torben; Yang, Shuting; Suo, Lingling; Wang, Tao; Gastineau, Guillaume; Nakamura, Tetsu; Cheung, Ho Nam; Omrani, Nour-Eddine; Ukita, Jinro; Semenov, Vladimir (Journal article; Peer reviewed, 2018)Wide disagreement among individual modeling studies has contributed to a debate on the role of recent sea ice loss in the Arctic amplification of global warming and the Siberian wintertime cooling trend. We perform coordinated ... -
Factors affecting extreme rainfall events in the South Pacific
Pariyar, Sunil Kumar; Keenlyside, Noel; Sorteberg, Asgeir; Spengler, Thomas; Bhatt, Bhuwan Chandra; Ogawa, Fumiaki (Journal article; Peer reviewed, 2020)Extreme rainfall events in the South Pacific are widespread and affected by various factors on different time scales. We use daily rainfall data from 20 stations over the South Pacific to investigate the characteristics ... -
Has a warm North Atlantic contributed to recent European cold winters?
Keenlyside, Noel; Omrani, Nour-Eddine (Peer reviewed; Journal article, 2014-06-02)The rise of global surface temperature waned during the last decade, despite increasing greenhouse gas concentrations. The temperature changes were most pronounced over northern hemisphere land masses during winter (Cohen ... -
Impact of Arctic sea ice variations on winter temperature anomalies in northern hemispheric land areas
Köenigk, Torben; Gao, Yongqi; Gastineau, Guillaume; Keenlyside, Noel; Nakamura, Tetsu; Ogawa, Fumiaki; Orsolini, Yvan; Semenov, Vladimir A.; Suo, Lingling; Tian, Tian; Wang, Tao; Wettstein, Justin; Yang, Shuting (Peer reviewed; Journal article, 2018-07-30)Coordinated numerical ensemble experiments with six different state-of-the-art atmosphere models have been used in order to evaluate the respective impact of the observed Arctic sea ice and sea surface temperature (SST) ... -
The impact of mean state errors on equatorial Atlantic interannual variability in a climate model
Ding, Hui; Keenlyside, Noel; Latif, Mojib; Park, Wonsun; Wahl, Sebastian (Peer reviewed; Journal article, 2015-02-23)Observations show that the Equatorial Atlantic Zonal Mode (ZM) obeys similar physics to the El Niño Southern Oscillation (ENSO): positive Bjerknes and delayed negative feedbacks. This implies the ZM may be predictable on ...