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Article ; Online: Data from the MOSAiC Arctic Ocean drift experiment.

Frickenhaus, Stephan / Ransby, Daniela / Shupe, Matthew / Jaiser, Ralf / Nicolaus, Marcel

2022 Volume 9, Issue 1, Page(s) 568

Language	English
Publishing date	2022-09-15
Publishing country	England
Document type	Journal Article
ZDB-ID	2775191-0
ISSN	2052-4463 ; 2052-4463
ISSN (online)	2052-4463
ISSN	2052-4463
DOI	10.1038/s41597-022-01678-8
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Conference proceedings ; Online: Investigation of radiative closure and cloud radiative effects based on ground-based and satellite observations during MOSAiC

Barrientos Velasco, C. / Griesche, H. / Hünerbein, A. / Macke, A. / Seifert, P. / Shupe, M. / Witthuhn, J. / Deneke, H.

XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)

2023

Abstract: Significant uncertainties in the prediction of future warming in the Arctic arise from our lack of understanding of governing processes, including cloud radiative feedbacks. The present study compares preliminary simulations of 1D radiative fluxes based ... ...

Abstract	Significant uncertainties in the prediction of future warming in the Arctic arise from our lack of understanding of governing processes, including cloud radiative feedbacks. The present study compares preliminary simulations of 1D radiative fluxes based on the Cloudnet and ShupeTurner cloud retrievals for the yearlong Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition. The analysis is conducted in the context of a radiative closure study at the surface and the top-of-the atmosphere for the upward and downward broadband solar and terrestrial radiative fluxes. The consistency of our simulations and satellite-based estimates from the Clouds and the Earth’s Radiant Energy System (CERES) are analysed by considering several atmospheric and surface-type conditions. Particular focus is given to the effect of clouds on the radiation budget. Based on our simulations and CERES estimates, we find that clouds increase the net radiative fluxes at the surface by about 35.5 W/m² for the entire MOSAiC expedition period. Nevertheless, based on in-situ observations, it is argued that significant uncertainties in the solar and terrestrial affect this estimate of cloud radiative effects. Our research will also address the spatiotemporal variability of clouds and how this might impact the comparison between the point-like ground measurements with the CERES satellite footprint.
Subject code	520
Language	English
Publishing country	de
Document type	Conference proceedings ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Book ; Online: Evaluation of turbulent dissipation rate retrievals from Doppler Cloud Radar

Shupe, M. D. / Brooks, I. M. / Canut, G.

eISSN: 1867-8548

2018

Abstract: Turbulent dissipation rate retrievals from cloud radar Doppler velocity measurements are evaluated using independent, in situ observations in Arctic stratocumulus clouds. In situ validation data sets of dissipation rate are derived using sonic anemometer ...

Abstract	Turbulent dissipation rate retrievals from cloud radar Doppler velocity measurements are evaluated using independent, in situ observations in Arctic stratocumulus clouds. In situ validation data sets of dissipation rate are derived using sonic anemometer measurements from a tethered balloon and high frequency pressure variation observations from a research aircraft, both flown in proximity to stationary, ground-based radars. Modest biases are found among the data sets in particularly low- or high-turbulence regimes, but in general the radar-retrieved values correspond well with the in situ measurements. Root mean square differences are typically a factor of 4–6 relative to any given magnitude of dissipation rate. These differences are no larger than those found when comparing dissipation rates computed from tethered-balloon and meteorological tower-mounted sonic anemometer measurements made at spatial distances of a few hundred meters. Temporal lag analyses suggest that approximately half of the observed differences are due to spatial sampling considerations, such that the anticipated radar-based retrieval uncertainty is on the order of a factor of 2–3. Moreover, radar retrievals are clearly able to capture the vertical dissipation rate structure observed by the in situ sensors, while offering substantially more information on the time variability of turbulence profiles. Together these evaluations indicate that radar-based retrievals can, at a minimum, be used to determine the vertical structure of turbulence in Arctic stratocumulus clouds.
Subject code	532 ; 551
Language	English
Publishing date	2018-01-15
Publishing country	de
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Book ; Online: Characteristic nature of vertical motions observed in Arctic mixed-phase stratocumulus

Sedlar, J. / Shupe, M. D.

eISSN: 1680-7324

2014

Abstract: Over the Arctic Ocean, little is known on cloud-generated buoyant overturning vertical motions within mixed-phase stratocumulus clouds. Characteristics of such motions are important for understanding the diabatic processes associated with the vertical ... ...

Abstract	Over the Arctic Ocean, little is known on cloud-generated buoyant overturning vertical motions within mixed-phase stratocumulus clouds. Characteristics of such motions are important for understanding the diabatic processes associated with the vertical motions, the lifetime of the cloud layer and its micro- and macrophysical characteristics. In this study, we exploit a suite of surface-based remote sensors over the high-Arctic sea ice during a weeklong period of persistent stratocumulus in August 2008 to derive the in-cloud vertical motion characteristics. In-cloud vertical velocity skewness and variance profiles are found to be strikingly different from observations within lower-latitude stratocumulus, suggesting these Arctic mixed-phase clouds interact differently with the atmospheric thermodynamics (cloud tops extending above a stable temperature inversion base) and with a different coupling state between surface and cloud. We find evidence of cloud-generated vertical mixing below cloud base, regardless of surface–cloud coupling state, although a decoupled surface–cloud state occurred most frequently. Detailed case studies are examined, focusing on three levels within the cloud layer, where wavelet and power spectral analyses are applied to characterize the dominant temporal and horizontal scales associated with cloud-generated vertical motions. In general, we find a positively correlated vertical motion signal amongst vertical levels within the cloud and across the full cloud layer depth. The coherency is dependent upon other non-cloud controlled factors, such as larger, mesoscale weather passages and radiative shielding of low-level stratocumulus by one or more cloud layers above. Despite the coherency in vertical velocity across the cloud, the velocity variances were always weaker near cloud top, relative to cloud middle and base. Taken in combination with the skewness, variance and thermodynamic profile characteristics, we observe vertical motions near cloud top that behave differently than those from lower within the cloud layer. Spectral analysis indicates peak cloud-generated w variance timescales slowed only modestly during decoupled cases relative to coupled; horizontal wavelengths only slightly increased when transitioning from coupling to decoupling. The similarities in scales suggests that perhaps the dominant forcing for all cases is generated from the cloud layer, and it is not the surface forcing that characterizes the time- and space scales of in-cloud vertical velocity variance. This points toward the resilient nature of Arctic mixed-phase clouds to persist when characterized by thermodynamic regimes unique to the Arctic.
Subject code	551
Language	English
Publishing date	2014-04-07
Publishing country	de
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: "Time to Talk About It: Physician Depression and Suicide" Video/Discussion Session for Interns, Residents, and Fellows.

Nagy, Christopher / Schwabe, Donna / Jones, Woodson / Brown, Alexander / Shupe, Matthew / Mancone, Angelica / Camillocci, James

MedEdPORTAL : the journal of teaching and learning resources

2016 Volume 12, Page(s) 10508

Abstract: Introduction: Physician wellness has garnered significant recent national attention within graduate medical education (GME). Unfortunately, the resources to proactively address burnout, depression, and suicide are lacking. The "Time to Talk About It: ... ...

Abstract	Introduction: Physician wellness has garnered significant recent national attention within graduate medical education (GME). Unfortunately, the resources to proactively address burnout, depression, and suicide are lacking. The "Time to Talk About It: Physician Depression and Suicide" video/discussion session is specifically designed for the GME community. Methods: The primary focus of this 60-minute video/discussion session is to promote an open dialogue among interns, residents, and fellows about depression and suicide within the profession of medicine. The centerpiece of the session is a 7-minute video featuring personal accounts from physicians at the San Antonio Uniformed Services Health Education Consortium (SAUSHEC). The materials associated with the publication include the video, a guide for facilitating group discussion following the video, a list of questions to guide small-group discussions, a session evaluation form, and examples of mental health resources for distribution at the end of the session. Results: A field test of the video/discussion session with 22 trainees from the pediatrics residency program at SAUSHEC was very well received. Their average response to "This session was an effective first step in promoting an open dialogue among physicians about depression and suicide within the profession" was 4.5 out of 5 (i.e., Strongly Agree). One hundred percent of participants answered "Yes" to the question "Would you recommend this session to other physicians?" Discussion: We hope that this resource will be useful to other institutions around the country as they confront physician burnout, depression, and suicide.
Language	English
Publishing date	2016-11-29
Publishing country	United States
Document type	Journal Article
ISSN	2374-8265
ISSN (online)	2374-8265
DOI	10.15766/mep_2374-8265.10508
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Book ; Online: The thermodynamic structure of summer Arctic stratocumulus and the dynamic coupling to the surface

Sotiropoulou, G. / Sedlar, J. / Tjernström, M. / Shupe, M. D. / Brooks, I. M. / Persson, P. O. G.

eISSN: 1680-7324

2014

Abstract: The vertical structure of Arctic low-level clouds and Arctic boundary layer is studied, using observations from ASCOS (Arctic Summer Cloud Ocean Study), in the central Arctic, in late summer 2008. Two general types of cloud structures are examined: the " ... ...

Abstract	The vertical structure of Arctic low-level clouds and Arctic boundary layer is studied, using observations from ASCOS (Arctic Summer Cloud Ocean Study), in the central Arctic, in late summer 2008. Two general types of cloud structures are examined: the "neutrally stratified" and "stably stratified" clouds. Neutrally stratified are mixed-phase clouds where radiative-cooling near cloud top produces turbulence that generates a cloud-driven mixed layer. When this layer mixes with the surface-generated turbulence, the cloud layer is coupled to the surface, whereas when such an interaction does not occur, it remains decoupled; the latter state is most frequently observed. The decoupled clouds are usually higher compared to the coupled; differences in thickness or cloud water properties between the two cases are however not found. The surface fluxes are also very similar for both states. The decoupled clouds exhibit a bimodal thermodynamic structure, depending on the depth of the sub-cloud mixed layer (SCML): clouds with shallower SCMLs are disconnected from the surface by weak inversions, whereas those that lay over a deeper SCML are associated with stronger inversions at the decoupling height. Neutrally stratified clouds generally precipitate; the evaporation/sublimation of precipitation often enhances the decoupling state. Finally, stably stratified clouds are usually lower, geometrically and optically thinner, non-precipitating liquid-water clouds, not containing enough liquid to drive efficient mixing through cloud-top cooling.
Subject code	551
Language	English
Publishing date	2014-11-28
Publishing country	de
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: July 2012 Greenland melt extent enhanced by low-level liquid clouds.

Bennartz, R / Shupe, M D / Turner, D D / Walden, V P / Steffen, K / Cox, C J / Kulie, M S / Miller, N B / Pettersen, C

Nature

2013 Volume 496, Issue 7443, Page(s) 83–86

Abstract: Melting of the world's major ice sheets can affect human and environmental conditions by contributing to sea-level rise. In July 2012, an historically rare period of extended surface melting was observed across almost the entire Greenland ice sheet, ... ...

Abstract	Melting of the world's major ice sheets can affect human and environmental conditions by contributing to sea-level rise. In July 2012, an historically rare period of extended surface melting was observed across almost the entire Greenland ice sheet, raising questions about the frequency and spatial extent of such events. Here we show that low-level clouds consisting of liquid water droplets ('liquid clouds'), via their radiative effects, played a key part in this melt event by increasing near-surface temperatures. We used a suite of surface-based observations, remote sensing data, and a surface energy-balance model. At the critical surface melt time, the clouds were optically thick enough and low enough to enhance the downwelling infrared flux at the surface. At the same time they were optically thin enough to allow sufficient solar radiation to penetrate through them and raise surface temperatures above the melting point. Outside this narrow range in cloud optical thickness, the radiative contribution to the surface energy budget would have been diminished, and the spatial extent of this melting event would have been smaller. We further show that these thin, low-level liquid clouds occur frequently, both over Greenland and across the Arctic, being present around 30-50 per cent of the time. Our results may help to explain the difficulties that global climate models have in simulating the Arctic surface energy budget, particularly as models tend to under-predict the formation of optically thin liquid clouds at supercooled temperatures--a process potentially necessary to account fully for temperature feedbacks in a warming Arctic climate.
MeSH term(s)	Arctic Regions ; Freezing ; Global Warming/statistics & numerical data ; Greenland ; Hot Temperature ; Ice Cover ; Infrared Rays ; Models, Theoretical ; Oceans and Seas ; Rain ; Time Factors ; Weather
Language	English
Publishing date	2013-04-04
Publishing country	England
Document type	Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S.
ZDB-ID	120714-3
ISSN	1476-4687 ; 0028-0836
ISSN (online)	1476-4687
ISSN	0028-0836
DOI	10.1038/nature12002
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Book ; Online: Cloud and boundary layer interactions over the Arctic sea ice in late summer

Shupe, M. D. / Persson, P. O. G. / Brooks, I. M. / Tjernström, M. / Sedlar, J. / Mauritsen, T. / Sjogren, S. / Leck, C.

eISSN: 1680-7324

2013

Abstract: Observations from the Arctic Summer Cloud Ocean Study (ASCOS), in the central Arctic sea-ice pack in late summer 2008, provide a detailed view of cloud–atmosphere–surface interactions and vertical mixing processes over the sea-ice environment. ... ...

Abstract	Observations from the Arctic Summer Cloud Ocean Study (ASCOS), in the central Arctic sea-ice pack in late summer 2008, provide a detailed view of cloud–atmosphere–surface interactions and vertical mixing processes over the sea-ice environment. Measurements from a suite of ground-based remote sensors, near-surface meteorological and aerosol instruments, and profiles from radiosondes and a helicopter are combined to characterize a week-long period dominated by low-level, mixed-phase, stratocumulus clouds. Detailed case studies and statistical analyses are used to develop a conceptual model for the cloud and atmosphere structure and their interactions in this environment. Clouds were persistent during the period of study, having qualities that suggest they were sustained through a combination of advective influences and in-cloud processes, with little contribution from the surface. Radiative cooling near cloud top produced buoyancy-driven, turbulent eddies that contributed to cloud formation and created a cloud-driven mixed layer. The depth of this mixed layer was related to the amount of turbulence and condensed cloud water. Coupling of this cloud-driven mixed layer to the surface boundary layer was primarily determined by proximity. For 75% of the period of study, the primary stratocumulus cloud-driven mixed layer was decoupled from the surface and typically at a warmer potential temperature. Since the near-surface temperature was constrained by the ocean–ice mixture, warm temperatures aloft suggest that these air masses had not significantly interacted with the sea-ice surface. Instead, back-trajectory analyses suggest that these warm air masses advected into the central Arctic Basin from lower latitudes. Moisture and aerosol particles likely accompanied these air masses, providing necessary support for cloud formation. On the occasions when cloud–surface coupling did occur, back trajectories indicated that these air masses advected at low levels, while mixing processes kept the mixed layer in equilibrium with the near-surface environment. Rather than contributing buoyancy forcing for the mixed-layer dynamics, the surface instead simply appeared to respond to the mixed-layer processes aloft. Clouds in these cases often contained slightly higher condensed water amounts, potentially due to additional moisture sources from below.
Subject code	551
Language	English
Publishing date	2013-09-24
Publishing country	de
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Book ; Online: Near-surface meteorology during the Arctic Summer Cloud Ocean Study (ASCOS)

de Boer, G. / Shupe, M. D. / Caldwell, P. M. / Bauer, S. E. / Persson, O. / Boyle, J. S. / Kelley, M. / Klein, S. A. / Tjernström, M.

eISSN: 1680-7324

evaluation of reanalyses and global climate models

2014

Abstract: Atmospheric measurements from the Arctic Summer Cloud Ocean Study (ASCOS) are used to evaluate the performance of three atmospheric reanalyses (European Centre for Medium Range Weather Forecasting (ECMWF)-Interim reanalysis, National Center for ... ...

Abstract	Atmospheric measurements from the Arctic Summer Cloud Ocean Study (ASCOS) are used to evaluate the performance of three atmospheric reanalyses (European Centre for Medium Range Weather Forecasting (ECMWF)-Interim reanalysis, National Center for Environmental Prediction (NCEP)-National Center for Atmospheric Research (NCAR) reanalysis, and NCEP-DOE (Department of Energy) reanalysis) and two global climate models (CAM5 (Community Atmosphere Model 5) and NASA GISS (Goddard Institute for Space Studies) ModelE2) in simulation of the high Arctic environment. Quantities analyzed include near surface meteorological variables such as temperature, pressure, humidity and winds, surface-based estimates of cloud and precipitation properties, the surface energy budget, and lower atmospheric temperature structure. In general, the models perform well in simulating large-scale dynamical quantities such as pressure and winds. Near-surface temperature and lower atmospheric stability, along with surface energy budget terms, are not as well represented due largely to errors in simulation of cloud occurrence, phase and altitude. Additionally, a development version of CAM5, which features improved handling of cloud macro physics, has demonstrated to improve simulation of cloud properties and liquid water amount. The ASCOS period additionally provides an excellent example of the benefits gained by evaluating individual budget terms, rather than simply evaluating the net end product, with large compensating errors between individual surface energy budget terms that result in the best net energy budget.
Subject code	551
Language	English
Publishing date	2014-01-13
Publishing country	de
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article: Polar Ocean Observations: A Critical Gap in the Observing System and Its Effect on Environmental Predictions From Hours to a Season.

Smith, Gregory C / Allard, Richard / Babin, Marcel / Bertino, Laurent / Chevallier, Matthieu / Corlett, Gary / Crout, Julia / Davidson, Fraser / Delille, Bruno / Gille, Sarah T / Hebert, David / Hyder, Patrick / Intrieri, Janet / Lagunas, José / Larnicol, Gilles / Kaminski, Thomas / Kater, Belinda / Kauker, Frank / Marec, Claudie /

Frontiers in Marine Science

2019 Volume 6

Abstract: There is a growing need for operational oceanographic predictions in both the Arctic and Antarctic polar regions. In the former, this is driven by a declining ice cover accompanied by an increase in maritime traffic and exploitation of marine resources. ... ...

Abstract	There is a growing need for operational oceanographic predictions in both the Arctic and Antarctic polar regions. In the former, this is driven by a declining ice cover accompanied by an increase in maritime traffic and exploitation of marine resources. Oceanographic predictions in the Antarctic are also important, both to support Antarctic operations and also to help elucidate processes governing sea ice and ice shelf stability. However, a significant gap exists in the ocean observing system in polar regions, compared to most areas of the global ocean, hindering the reliability of ocean and sea ice forecasts. This gap can also be seen from the spread in ocean and sea ice reanalyses for polar regions which provide an estimate of their uncertainty. The reduced reliability of polar predictions may affect the quality of various applications including search and rescue, coupling with numerical weather and seasonal predictions, historical reconstructions (reanalysis), aquaculture and environmental management including environmental emergency response. Here, we outline the status of existing near-real time ocean observational efforts in polar regions, discuss gaps, and explore perspectives for the future. Specific recommendations include a renewed call for open access to data, especially real-time data, as a critical capability for improved sea ice and weather forecasting and other environmental prediction needs. Dedicated efforts are also needed to make use of additional observations made as part of the Year of Polar Prediction (YOPP; 2017-2019) to inform optimal observing system design. To provide a polar extension to the Argo network, it is recommended that a network of ice-borne sea ice and upper-ocean observing buoys be deployed and supported operationally in ice-covered areas together with autonomous profiling floats and gliders (potentially with ice detection capability) in seasonally ice covered seas. Finally, additional efforts to better measure and parameterize surface exchanges in polar regions are much needed to improve coupled environmental prediction.
Language	English
Publishing date	2019-08-13
Publishing country	Switzerland
Document type	Journal Article
ZDB-ID	2757748-X
ISSN	2296-7745
ISSN	2296-7745
DOI	10.3389/fmars.2019.00429
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