scholarly journals The North Atlantic Waveguide and Downstream Impact Experiment

2018 ◽  
Vol 99 (8) ◽  
pp. 1607-1637 ◽  
Author(s):  
Andreas Schäfler ◽  
George Craig ◽  
Heini Wernli ◽  
Philippe Arbogast ◽  
James D. Doyle ◽  
...  
Keyword(s):  
North Atlantic ◽  
Subsequent Development ◽  
Jet Stream ◽  
Atmospheric Measurements ◽  
Weather Impact ◽  
The North ◽  
Impact Experiment ◽  
Research Aircraft ◽  
The North Atlantic ◽  
The Impact

AbstractThe North Atlantic Waveguide and Downstream Impact Experiment (NAWDEX) explored the impact of diabatic processes on disturbances of the jet stream and their influence on downstream high-impact weather through the deployment of four research aircraft, each with a sophisticated set of remote sensing and in situ instruments, and coordinated with a suite of ground-based measurements. A total of 49 research flights were performed, including, for the first time, coordinated flights of the four aircraft: the German High Altitude and Long Range Research Aircraft (HALO), the Deutsches Zentrum für Luft- und Raumfahrt (DLR) Dassault Falcon 20, the French Service des Avions Français Instrumentés pour la Recherche en Environnement (SAFIRE) Falcon 20, and the British Facility for Airborne Atmospheric Measurements (FAAM) BAe 146. The observation period from 17 September to 22 October 2016 with frequently occurring extratropical and tropical cyclones was ideal for investigating midlatitude weather over the North Atlantic. NAWDEX featured three sequences of upstream triggers of waveguide disturbances, as well as their dynamic interaction with the jet stream, subsequent development, and eventual downstream weather impact on Europe. Examples are presented to highlight the wealth of phenomena that were sampled, the comprehensive coverage, and the multifaceted nature of the measurements. This unique dataset forms the basis for future case studies and detailed evaluations of weather and climate predictions to improve our understanding of diabatic influences on Rossby waves and the downstream impacts of weather systems affecting Europe.

scholarly journals The Impact of Dropsonde and Extra Radiosonde Observations during NAWDEX in Autumn 2016

2020 ◽  
Vol 148 (2) ◽  
pp. 809-824 ◽  
Author(s):  
Matthias Schindler ◽  
Martin Weissmann ◽  
Andreas Schäfler ◽  
Gabor Radnoti
Keyword(s):  
North Atlantic ◽  
Forecast Error ◽  
The North ◽  
Impact Experiment ◽  
Beneficial Impact ◽  
Research Aircraft ◽  
Northern Atlantic ◽  
Intensive Observation ◽  
The Impact ◽  
Unique Dataset

Abstract Dropsonde observations from three research aircraft in the North Atlantic region, as well as several hundred additionally launched radiosondes over Canada and Europe, were collected during the international North Atlantic Waveguide and Downstream Impact Experiment (NAWDEX) in autumn 2016. In addition, over 1000 dropsondes were deployed during NOAA’s Sensing Hazards with Operational Unmanned Technology (SHOUT) and Reconnaissance missions in the west Atlantic basin, supplementing the conventional observing network for several intensive observation periods. This unique dataset was assimilated within the framework of cycled data denial experiments for a 1-month period performed with the global model of the ECMWF. Results show a slightly reduced mean forecast error (1%–3%) over the northern Atlantic and Europe by assimilating these additional observations, with the most prominent error reductions being linked to Tropical Storm Karl, Cyclones Matthew and Nicole, and their subsequent interaction with the midlatitude waveguide. The evaluation of Forecast Sensitivity to Observation Impact (FSOI) indicates that the largest impact is due to dropsondes near tropical storms and cyclones, followed by dropsondes over the northern Atlantic and additional Canadian radiosondes. Additional radiosondes over Europe showed a comparatively small beneficial impact.

scholarly journals Medium-term exposure of the North Atlantic copepod <i>Calanus finmarchicus</i> (Gunnerus, 1770) to CO<sub>2</sub>-acidified seawater: effects on survival and development

2013 ◽  
Vol 10 (11) ◽  
pp. 7481-7491 ◽  
Author(s):  
S. A. Pedersen ◽  
B. H. Hansen ◽  
D. Altin ◽  
A. J. Olsen
Keyword(s):  
North Atlantic ◽  
Growth And Development ◽  
Stage Iv ◽  
Subsequent Development ◽  
Experimental System ◽  
Calanus Finmarchicus ◽  
Medium Term ◽  
The North ◽  
The North Atlantic ◽  
The Impact

Abstract. The impact of medium-term exposure to CO2-acidified seawater on survival, growth and development was investigated in the North Atlantic copepod Calanus finmarchicus. Using a custom developed experimental system, fertilized eggs and subsequent development stages were exposed to normal seawater (390 ppm CO2) or one of three different levels of CO2-induced acidification (3300, 7300, 9700 ppm CO2). Following the 28-day exposure period, survival was found to be unaffected by exposure to 3300 ppm CO2, but significantly reduced at 7300 and 9700 ppm CO2. Also, the proportion of copepodite stages IV to VI observed in the different treatments was significantly affected in a manner that may indicate a CO2-induced retardation of the rate of ontogenetic development. Morphometric analysis revealed a significant increase in size (prosome length) and lipid storage volume in stage IV copepodites exposed to 3300 ppm CO2 and reduced size in stage III copepodites exposed to 7300 ppm CO2. Together, the findings indicate that a pCO2 level ≤2000 ppm (the highest CO2 level expected by the year 2300) will probably not directly affect survival in C. finmarchicus. Longer term experiments at more moderate CO2 levels are, however, necessary before the possibility that growth and development may be affected below 2000 ppm CO2 can be ruled out.

Tropical cloud-radiative changes contribute to robust DJF jet exit strengthening over Europe under global warming

2021 ◽  
Author(s):  
Nicole Albern ◽  
Aiko Voigt ◽  
Joaquim G. Pinto
Keyword(s):  
Climate Change ◽  
North Atlantic ◽  
Storm Track ◽  
Tropical Pacific ◽  
Jet Stream ◽  
The North ◽  
The North Atlantic ◽  
Stream Response ◽  
The Impact ◽  
North Atlantic Jet

&lt;p&gt;During boreal winter (December to February, DJF), the North Atlantic jet stream and storm track are expected to extend eastward over Europe in response to climate change. This will affect future weather and climate over Europe, for example by steering storms which are associated with strong winds and heavy precipitation towards Europe. The jet stream and storm track responses over Europe are robust across coupled climate models of phases 3, 5, and 6 of the Coupled Model Intercomparison Project (CMIP; Harvey et al., 2020, JGR-A, https://doi.org/10.1029/2020JD032701). We show that the jet stream response is further robust across CMIP5 models of varying complexity ranging from coupled climate models to atmosphere-only General Circulation Models (GCMs) with prescribed sea-surface temperatures (SSTs) and sea-ice cover. In contrast to the jet stream response over Europe, the jet stream response over the North Atlantic is not robust in the coupled climate models and the atmosphere-only GCMs.&lt;/p&gt;&lt;p&gt;In addition to the CMIP5 simulations, we investigate Amip-like simulations with the atmospheric components of ICON-NWP, and the CMIP5 models MPI-ESM-LR and IPSL-CM5A-LR that apply the cloud-locking method to break the cloud-radiation-circulation coupling and to diagnose the contribution of cloud-radiative changes on the jet stream response to climate change. In the simulations, SSTs are prescribed to isolate the impact of cloud-radiative changes via the atmospheric pathway, i.e., via changes in atmospheric cloud-radiative heating, and global warming is mimicked by a uniform 4K SST increase (cf. Albern et al., 2019, JAMES, https://doi.org/10.1029/2018MS001592 and Voigt et al., 2019, J. Climate, https://doi.org/10.1175/JCLI-D-18-0810.1). In all three models, cloud-radiative changes contribute significantly and robustly to the eastward extension of the North Atlantic jet stream towards Europe. At the same time, cloud-radiative changes contribute to the model uncertainty over the North Atlantic. In addition to the jet stream response, we investigate the impact of cloud-radiative changes on the storm track response in ICON-NWP and discuss similarities and differences between the jet stream and storm track responses over the North Atlantic-European region.&lt;/p&gt;&lt;p&gt;In ICON-NWP, the impact of cloud-radiative changes on the jet stream response is dominated by tropical cloud-radiative changes while midlatitude and polar cloud-radiative changes have a minor impact. A further division of the tropics into four smaller tropical regions that cover the western tropical Pacific, the eastern tropical Pacific, the tropical Atlantic, and the Indian Ocean shows that cloud-radiative changes over the western tropical Pacific, eastern tropical Pacific, and Indian Ocean all contribute about equally to the eastward extension of the North Atlantic jet stream towards Europe because these regions exhibit substantial upper-tropospheric cloud-radiative heating in response to climate change. At the same time, cloud-radiative changes over the tropical Atlantic hardly contribute to the jet response over Europe because changes in atmospheric cloud-radiative heating under climate change are small in this region. As for the impact of global cloud-radiative changes, we also discuss the impact of the regional cloud-radiative changes on the storm track response over the North Atlantic-European region to climate change.&lt;/p&gt;

A Robust Intensification of Wintertime Jet Stream Extremes in Future Climates

2021 ◽  
Author(s):  
Ben Harvey
Keyword(s):  
North America ◽  
North Atlantic ◽  
Western Europe ◽  
Subsequent Development ◽  
Jet Stream ◽  
Wind Speeds ◽  
The North ◽  
Sequence Of Events ◽  
The North Atlantic ◽  
Jet Streak

&lt;p&gt;The east coast of North America experienced a record-breaking jet stream event on 20 Feb 2019, with peak wind speeds exceeding 110 m/s observed by weather balloons over Nova Scotia. At the time this was the strongest wind speed ever recorded over North America. The extreme `jet streak' propagated out over the North Atlantic where it played a key role in the subsequent development of a large and rapidly deepening cyclone on 22 Feb 2019. The cyclone had little societal impact because it did not make landfall. It did however act to amplify a large scale Rossby wave, producing a strong poleward advection of warm air towards western Europe, and leading to record-breaking February warmth in several European countries on 27 Feb 2019. The whole sequence of events took just over a week to complete.&lt;/p&gt;&lt;p&gt;This case provides an illustration of how climate extremes (here the record warmth in western Europe) are often the result of complex and chaotic nonlinear interactions of the atmosphere on weather timescales. The particular sequence of events is not uncommon, but both the strength of the initial jet streak over North America and the resulting temperatures in Europe were. Given the observed trend in surface temperatures, it seems likely that the temperatures were at least partly enhanced in a passive way by the warming climate. A more difficult question to answer is whether climate change is also impacting the frequency or amplitude of the preceding sequence of weather events. As a first step to answering this question, this study asks the question: do we expect extreme jet streak events to intensify in future?&lt;/p&gt;&lt;p&gt;Based on an analysis of CMIP simulations over the North Atlantic, we find a robust intensification of wintertime jet extremes in future climates, with the strongest instantaneous wind speeds increasing in every model. This contrasts with the strength of the time mean jet streams, which do not exhibit a robust change across the ensemble. Possible reasons for the differing behaviour of the mean winds and the extreme winds are discussed and a hypothesis is suggested to explain the robust increase in the latter.&lt;/p&gt;

Measurement of NOx and Ozone over the North Atlantic Ocean.

2020 ◽  
Author(s):  
James Lee ◽  
Freya Squires ◽  
Simone Andersen ◽  
Jim Hopkins ◽  
Dominika Pasternak ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Atmospheric Measurements ◽  
The North ◽  
Research Aircraft ◽  
Natural Emissions ◽  
The North Atlantic ◽  
The Difference ◽  
The Uk

&lt;p&gt;Tropospheric ozone (O&lt;sub&gt;3&lt;/sub&gt;) can adversely affect human health and environmental ecosystems and it is therefore vitally important to understand its formation pathways from both natural and anthropogenic precursors. Background O&lt;sub&gt;3&lt;/sub&gt; levels in the Northern Hemisphere have increased by more than a factor of two over the last century and it is believed that this increase is strongly tied to the increase in and distribution of anthropogenic nitrogen oxide (N0&lt;sub&gt;x&lt;/sub&gt;) emissions. This is important as the changing level of O&lt;sub&gt;3&lt;/sub&gt; in the background troposphere impacts the ability of countries downwind to achieve their air quality standards.&lt;/p&gt;&lt;p&gt;As part of the NERC funded North Atlantic Climate System Integrated Study (ACSiS) and Methane Observations and Yearly Assessments (MOYA) projects, multiple research flights have taken place over the North Atlantic Ocean, spanning an area from 55&lt;sup&gt;o&lt;/sup&gt;N to 12&lt;sup&gt;o&lt;/sup&gt;N and 8&lt;sup&gt;o&lt;/sup&gt;W to 25&lt;sup&gt;o&lt;/sup&gt;W using the UK&amp;#8217;s large research aircraft (The Facility for Airborne Atmospheric Measurements &amp;#8211; FAAM). Flights took place in all seasons from 2017 &amp;#8211; 2020. A variety of gas and aerosol measurements were made, including NO&lt;sub&gt;x&lt;/sub&gt;, O&lt;sub&gt;3, &lt;/sub&gt;CO and a range of VOCs and an overview of the data is presented here. Measurements were taken in a range of air masses, including biomass burning outflow from West Africa, urban outflow from Europe and emissions from the busy shipping lanes to the West of Portugal.&lt;/p&gt;&lt;p&gt;Data was analysed to assess O&lt;sub&gt;3&lt;/sub&gt; formation from the different emission sources, in particular examining the difference between anthropogenic and natural emissions. In addition, the output of regional chemistry models is compared to the data in order to assess the performance of the models in predicting O&lt;sub&gt;3&lt;/sub&gt; and its precursors.&lt;/p&gt;

scholarly journals Chronic exposure of the North Atlantic copepod <i>Calanus finmarchicus</i> (Gunnerus, 1770) to CO<sub>2</sub>-acidified seawater; effects on survival, growth and development

2013 ◽  
Vol 10 (3) ◽  
pp. 5273-5300 ◽  
Author(s):  
S. A. Pedersen ◽  
B. H. Hansen ◽  
D. Altin ◽  
A. J. Olsen
Keyword(s):  
North Atlantic ◽  
Growth And Development ◽  
Chronic Exposure ◽  
Stage Iv ◽  
Subsequent Development ◽  
Exposure Period ◽  
Calanus Finmarchicus ◽  
The North ◽  
The North Atlantic ◽  
The Impact

Abstract. The impact of chronic exposure to CO2-acidified seawater on survival, growth and development was investigated in the North Atlantic copepod Calanus finmarchicus. Using a custom developed microcosm system fertilized eggs and subsequent development stages were exposed to normal seawater (390 ppm CO2) or one of three different levels of CO2-induced acidification (3300, 7300, 9700 ppm CO2). Following the 28 day exposure period survival was found to be unaffected by exposure to 3300 ppm CO2, but significantly reduced at 7300 and 9700 ppm CO2. Also, the proportion of copepodite stages IV to VI observed in the different treatments was significantly affected in a manner that may indicate a CO2-induced retardation of the rate of ontogenetic development. Morphometric analysis revealed a significant increase in size (prosome length) and lipid storage volume in stage IV copepodites exposed to 3300 ppm CO2 and reduced size in stage III copepodites exposed to 7300 ppm CO2. Together, the findings indicate that a pCO2 level ≤2000 ppm (the highest CO2 level expected within year 2300) will probably not directly affect survival in C. finmarchicus. Long-term experiments at more moderate CO2 levels are however necessary before the possibility that growth and development may be affected below ≤2000 ppm CO2 can be ruled out.

Which regional cloud-radiative changes are most important for the global warming response of the midlatitude jet streams?

2020 ◽  
Author(s):  
Nicole Albern ◽  
Aiko Voigt ◽  
David W. J. Thompson ◽  
Joaquim G. Pinto
Keyword(s):  
Global Warming ◽  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
North Atlantic ◽  
Radiative Heating ◽  
Jet Stream ◽  
Jet Streams ◽  
The North ◽  
The North Atlantic ◽  
The Impact

&lt;p&gt;Clouds and the midlatitude circulation are strongly coupled via radiation. Previous studies showed that global cloud-radiative changes contribute significantly to the global warming response of the midlatitude circulation. Here, we investigate the impact of regional cloud-radiative changes and identify which regional cloud-radiative changes are most important for the impact of global cloud-radiative changes. We show how tropical, midlatitude and polar cloud-radiative changes modify the annual-mean, wintertime and summertime jet stream response to global warming across ocean basins. To this end, we perform global simulations with the atmospheric component of the ICOsahedral Nonhydrostatic (ICON) model. We prescribe sea surface temperatures (SST) to isolate the impact of cloud-radiative changes via the atmospheric pathway, i.e. changes in atmospheric cloud-radiative heating, and mimic global warming by a uniform 4K SST increase. We apply the cloud-locking method to break the cloud-radiation-circulation coupling and to decompose the circulation response into contributions from cloud-radiative changes and from the SST increase.&lt;/p&gt;&lt;p&gt;In response to global warming, the North Atlantic, North Pacific, Northern Hemisphere and Southern Hemisphere jet streams shift poleward and the North Atlantic, Northern Hemisphere and Southern Hemisphere jets strengthen. Global cloud-radiative changes contribute to these jet responses in all ocean basins. &lt;span&gt;In the annual-mean and DJF, tropical and midlatitude cloud-radiative changes contribute significantly to the poleward jet shift in all ocean basins. &lt;/span&gt;&lt;span&gt;P&lt;/span&gt;&lt;span&gt;olar cloud-radiative changes shift the jet streams &lt;/span&gt;&lt;span&gt;poleward &lt;/span&gt;&lt;span&gt;in the northern hemispheric ocean basins &lt;/span&gt;&lt;span&gt;but&lt;/span&gt; &lt;span&gt;equatorward &lt;/span&gt;&lt;span&gt;in the Southern Hemisphere. In JJA, the poleward jet shift is small in all ocean basins. In contrast to the jet shift, the global cloud-radiative impacts on the 850hPa zonal wind and jet strength responses &lt;/span&gt;&lt;span&gt;result predominantly from &lt;/span&gt;&lt;span&gt;tropical cloud-radiative &lt;/span&gt;&lt;span&gt;changes&lt;/span&gt;&lt;span&gt;.&lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;The cloud-radiative impact on the jet shift can be related to changes in upper-tropospheric baroclinicity via increases in upper-tropospheric meridional temperature gradients, enhanced wave activity and increased eddy momentum fluxes. However, the response of the atmospheric temperature to cloud-radiative heating is &lt;/span&gt;&lt;span&gt;more difficult to understand because it is modulated by other small-scale processes such as convection and the circulation.&lt;/span&gt;&lt;span&gt; Our results help to understand the jet stream response to global warming and highlight the importance of regional cloud-radiative changes for this response, &lt;/span&gt;&lt;span&gt;in particular those in the tropics&lt;/span&gt;&lt;span&gt;.&lt;/span&gt;&lt;/p&gt;

Preaching and Sermons

2017 ◽  
Author(s):  
Robert H. Ellison
Keyword(s):  
Eighteenth Century ◽  
North Atlantic ◽  
Religious Revival ◽  
Early Nineteenth Century ◽  
Denominational Identity ◽  
The North ◽  
The North Atlantic ◽  
The One ◽  
The Impact

Prompted by the convulsions of the late eighteenth century and inspired by the expansion of evangelicalism across the North Atlantic world, Protestant Dissenters from the 1790s eagerly subscribed to a millennial vision of a world transformed through missionary activism and religious revival. Voluntary societies proliferated in the early nineteenth century to spread the gospel and transform society at home and overseas. In doing so, they engaged many thousands of converts who felt the call to share their experience of personal conversion with others. Though social respectability and business methods became a notable feature of Victorian Nonconformity, the religious populism of the earlier period did not disappear and religious revival remained a key component of Dissenting experience. The impact of this revitalization was mixed. On the one hand, growth was not sustained in the long term and, to some extent, involvement in interdenominational activity undermined denominational identity; on the other hand, Nonconformists gained a social and political prominence they had not enjoyed since the middle of the seventeenth century and their efforts laid the basis for the twentieth-century explosion of evangelicalism in Africa, Asia, and South America.

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