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- Collaud Coen, Martine, et al.
(författare)
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Multidecadal trend analysis of in situ aerosol radiative properties around the world
- 2020
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Ingår i: Atmospheric Chemistry And Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 20:14, s. 8867-8908
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Tidskriftsartikel (refereegranskat)abstract
- In order to assess the evolution of aerosol parameters affecting climate change, a long-term trend analysis of aerosol optical properties was performed on time series from 52 stations situated across five continents. The time series of measured scattering, backscattering and absorption coefficients as well as the derived single scattering albedo, backscattering fraction, scattering and absorption Angstrom exponents covered at least 10 years and up to 40 years for some stations. The non-parametric seasonal Mann-Kendall (MK) statistical test associated with several pre-whitening methods and with Sen's slope was used as the main trend analysis method. Comparisons with general least mean square associated with autoregressive bootstrap (GLS/ARB) and with standard least mean square analysis (LMS) enabled confirmation of the detected MK statistically significant trends and the assessment of advantages and limitations of each method. Currently, scattering and backscattering coefficient trends are mostly decreasing in Europe and North America and are not statistically significant in Asia, while polar stations exhibit a mix of increasing and decreasing trends. A few increasing trends are also found at some stations in North America and Australia. Absorption coefficient time series also exhibit primarily decreasing trends. For single scattering albedo, 52 % of the sites exhibit statistically significant positive trends, mostly in Asia, eastern/northern Europe and the Arctic, 22 % of sites exhibit statistically significant negative trends, mostly in central Europe and central North America, while the remaining 26 % of sites have trends which are not statistically significant. In addition to evaluating trends for the overall time series, the evolution of the trends in sequential 10-year segments was also analyzed. For scattering and backscattering, statistically significant increasing 10-year trends are primarily found for earlier periods (10-year trends ending in 2010-2015) for polar stations and Mauna Loa. For most of the stations, the present-day statistically significant decreasing 10-year trends of the single scattering albedo were preceded by not statistically significant and statistically significant increasing 10-year trends. The effect of air pollution abatement policies in continental North America is very obvious in the 10-year trends of the scattering coefficient - there is a shift to statistically significant negative trends in 2009-2012 for all stations in the eastern and central USA. This long-term trend analysis of aerosol radiative properties with a broad spatial coverage provides insight into potential aerosol effects on climate changes.
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| 4. |
- Vichi, Marcello, et al.
(författare)
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Effects of an Explosive Polar Cyclone Crossing the Antarctic Marginal Ice Zone
- 2019
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Ingår i: Geophysical Research Letters. - : AMER GEOPHYSICAL UNION. - 0094-8276 .- 1944-8007. ; 46:11, s. 5948-5958
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Tidskriftsartikel (refereegranskat)abstract
- Antarctic sea ice shows a large degree of regional variability, which is partly driven by severe weather events. Here we bring a new perspective on synoptic sea ice changes by presenting the first in situ observations of an explosive extratropical cyclone crossing the winter Antarctic marginal ice zone (MIZ) in the South Atlantic. This is complemented by the analysis of subsequent cyclones and highlights the rapid variations that ice-landing cyclones cause on sea ice: Midlatitude warm oceanic air is advected onto the ice, and storm waves generated close to the ice edge contribute to the maintenance of an unconsolidated surface through which waves propagate far into the ice. MIZ features may thus extend further poleward in the Southern Ocean than currently estimated. A concentration-based MIZ definition is inadequate, since it fails to describe a sea ice configuration which is deeply rearranged by synoptic weather. Plain Language Summary The extent of Antarctic sea ice is characterized by large regional variations that are in stark contrast with the alarming decreasing trends found in the Arctic. This is partly due to the presence of severe weather events, like extratropical cyclones travelling through the Southern Ocean and reaching the marginal ice zone (MIZ). The MIZ is a region where the ocean, atmosphere, and sea ice processes are closely interlinked. We provide direct evidence of how winter polar cyclones rearrange the MIZ and how their effects extend into the ice-covered region as far as the Antarctic continent. We present the first observations of large ice drift, ice concentration, and temperature changes as an explosively deepening cyclone crosses the MIZ. This case study is complemented by analysis of subsequent but more frequent storms that confirms how storminess in the Southern Ocean maintains a sea ice surface that is less compact, more mobile, and more extended than previously anticipated. Our results urge the scientific community to revise the current definition of the MIZ and improve its representation in models to better include the role of polar cyclones in detecting Antarctic sea ice trends.
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| 5. |
- Visser, Els, et al.
(författare)
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Neoadjuvant chemotherapy or chemoradiotherapy for adenocarcinoma of the esophagus
- 2018
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Ingår i: Journal of Surgical Oncology. - : WILEY. - 0022-4790 .- 1096-9098. ; 117:8, s. 1687-1696
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundThe optimal treatment strategy for patients with esophageal adenocarcinoma (EAC) remains undetermined. This study compared outcomes in patients undergoing neoadjuvant chemotherapy (nCT) and neoadjuvant chemoradiotherapy (nCRT) for EAC. MethodsPatients who underwent nCT or nCRT followed by surgery for EAC were identified from a prospective database (2000-2017) and included. After propensity score matching, the impact of the treatments on postoperative complications, in-hospital mortality, pathological outcomes, and survival rates were compared. ResultsOf the 396 eligible patients, 262 patients were analysed following matching with 131 patients in both groups. There were no significant differences between the nCT and nCRT groups for overall complications (59% vs 57%, P=0.802) or in-hospital mortality (2% vs 0%, P=0.156). Patients who had nCRT had more R0 resections (93% vs 83%, P=0.013), and higher pathological complete response rates (15% vs 5%, P<0.001). No differences in 5-year overall survival rates (nCT vs nCRT; 44% vs 33%, P=0.645) were found. ConclusionIn this study no differences between nCT and nCRT were seen in postoperative complications and in-hospital mortality in patients treated for EAC. Inspite of improved complete resection and pathological response there was no difference in the overall survival between the treatment modalities.
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| 6. |
- Niemi, MEK, et al.
(författare)
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- 2021
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swepub:Mat__t
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| 7. |
- Kanai, M, et al.
(författare)
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- 2023
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swepub:Mat__t
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