30 June 2019, Volume 30 Issue 2

    

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  Contents Vol. 30 No. 2 June 2019

  Advances in Polar Science. 2019, 30(2): 0-0.

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  Advances in Polar Science
  Contents Vol. 30 No. 2 June 2019
  
  Articles
  
  Interaction of diabatic processes, large-scale eddies and the mean atmospheric circulation over the Atlantic, Arctic and Eurasia
  Ralf JAISER, Dörthe HANDORF & Klaus DETHLOFF
  Surface energy balance on the Antarctic plateau as measured with an automatic weather station during 2014
  DING Minghu, Anubha AGRAWAL, Petra HEIL & YANG Diyi
  An open-source albedo-wand for the measurement of sea ice albedo
  Christian KATLEIN
  Modified Rammsonde tests in layered compacted snow
  ZHUANG Feng, LU Peng, LI Zhijun, HAN Hongwei & LI Wei
  Investigation of PMSE echoes characteristics using the discontinuous EISCAT UHF observation and its relation with space environment 132
  Abdur RAUF, LI Hailong, Safi ULLAH, WANG Maoyan & MENG Lin
  
  Letters
  Effects of vegetation on the structure and diversity of soil bacterial communities in the Arctic tundra
  MA Yue, WANG Nengfei, WANG Shuang, HAN Wenbing, LIU Jie, YU Yong, GUO Li & YANG Guanpin
  Early Cenozoic diorite and diabase from Doumer Island, Antarctic Peninsula: zircon U-Pb geochronology, petrogenesis and tectonic implications
  CUI Jiawei, HU Jianmin, PEI Junling, CHEN Hong, DU Xingxing & WEI Lijie
  
  Cover picture: Melt ponds on sea ice off Baffin Island characteristically impact the albedo–the surface’s capability to reflect sunlight (paper by Christian Katlein, page 106)
  
Articles
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  Interaction of diabatic processes, large-scale eddies and the mean atmospheric circulation over the Atlantic, Arctic and Eurasia

  Ralf JAISER, Dörthe HANDORF, Klaus DETHLOFF

  Advances in Polar Science. 2019, 30(2): 81-92. https://doi.org/10.13679/j.advps.2018.0013

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  In the last decade, the atmospheric part of the climate system experienced a shift from pronounced zonal to stronger meridional flow configurations and regionally diverse changes and trends. The climate system shows complex interactions and nonlinear behavior, manifested in global warming, rising ocean temperatures and the retreat of Arctic sea ice. Although atmospheric trends and changes are observed, underlying processes are not well understood. In this study we diagnose the interaction of large-scale atmospheric eddies and the mean flow with respect to diabatic heating and cooling processes that impact on the atmospheric advection of heat. For this purpose, three-dimensional Eliassen-Palm flux theory is used in combination with an analysis of the thermodynamic equation, diabatic heating and cooling and heat advection. The most recent decades of observed winter climate are evaluated in terms of climatology and trends over the Atlantic, Arctic and Eurasia. The change of the atmospheric circulation and related processes differ between early and late winter. In early winter, the interaction of macro-turbulent eddies with the mean flow is inhibited at the Atlantic jet stream entrance region and atmospheric heat is meridionally advected into the Arctic, both related to strong high pressure anomalies. In late winter, these anomalies are inverted and a negative phase of the Arctic Oscillation with a more wavy mean flow and a tendency towards stronger meridionalization is observed.
  
  
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  Surface energy balance on the Antarctic plateau as measured with an automatic weather station during 2014

  Minghu DING, Anubha AGRAWAL, Petra HEIL, Diyi YANG

  Advances in Polar Science. 2019, 30(2): 93-105. https://doi.org/10.13679/j.advps.2018.0050

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  AWS data during 2014 collected at PANDA-N station, on the East Antarctica Plateau, are analysed. Net Short Wave Radiation (Q_SWR), net Long Wave Radiation (Q_LWR), sensible (Q_H), latent (Q_L) and subsurface or ground (Q_G) heat fluxes are computed. Annual averages for Q_SWR, Q_LWR, Q_H, Q_L and Q_G of 19.65, −49.16, 26.40, −0.77 and 3.86 W·m⁻² were derived based on an albedo value of 0.8. Q_SWR and Q_H are the major sources of heat gain to the surface and Q_LWR is the major component of heat loss from the surface. An iterative method is used to estimate surface temperature in this paper; surface temperature of snow/ice is gradually increased or decreased, thereby changing longwave radiation, sensible, latent and subsurface heat fluxes, so that the net energy balance becomes zero. Mass loss due to sublimation at PANDA-N station for 2014 is estimated to be 12.18 mm w.e.·a⁻¹; and mass gain due to water vapour deposition is estimated to be 3.58 mm w.e.·a⁻¹. Thus the net mass loss due to sublimation/deposition is 8.6 mm w.e.·a⁻¹. This study computes surface energy fluxes using a model, instead of direct measurements. Also there are missing data especially for wind speed, though 2 m air temperature data is almost continuously available throughout the year. The uncertainties of albedo, wind speed and turbulent fluxes cause the most probable error in monthly values of Q_LWR, Q_H, Q_L, Q_G and surface temperature of about ±4%, ±20%, ±50%, ±11% and ±0.74 K respectively.
  
  
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  An open-source albedo-wand for the measurement of sea ice albedo

  Christian KATLEIN

  Advances in Polar Science. 2019, 30(2): 106-117. https://doi.org/10.13679/j.advps.2019.0002

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  Surface albedo is defined as the ratio of incident and reflected solar irradiance and describes the ability of a surface to reflect, rather than absorb incident solar shortwave radiation. It is thus a crucial parameter in the climate system, particularly in the polar oceans. Sea ice albedo is a main driver for light transmission into the polar oceans and thus has a high impact on ocean warming, ice melting and marine primary production. During spring and summer, sea ice albedo can exhibit a significant spatial variability caused by meltwater accumulations on the ice. While complex and expensive solutions for albedo measurements are already available, we want to present a simple open-source design that allows for affordable mapping of spatially varying surface albedo on sea ice and beyond. Our solution is based on off-the-shelf components, such as an Arduino microcontroller integrating affordable light sensors, a GPS unit, data recording on memory card and data display into a simple field strengthened unit. We provide example data from two Arctic field deployments showing the capabilities and limitations of this system.
  
  
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  Modified Rammsonde tests in layered compacted snow

  Feng ZHUANG, Peng LU, Zhijun LI, Hongwei HAN, Wei LI

  Advances in Polar Science. 2019, 30(2): 118-131. https://doi.org/10.13679/j.advps.2019.0003

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  Investigation of the physical and mechanical properties of snow has long been a topic of interest to researchers as the construction of compacted-snow runways in Antarctica developed. In an attempt to assess the strength of layered compacted seasonal snow, penetration tests using modified Rammsonde were conducted in Harbin, China in early 2018. Compared with previous models, the modified Rammsonde is lighter overall, with improved resolution; thus, it is more suitable for seasonal snow; the mechanical structure was adjusted, and the reading of depth data is more convenient. A total of 74 penetration tests were carried out and the results were analyzed both qualitatively and quantitatively. The results of these analyses demonstrated the applicability of the device, and revealed that several factors affect the cone penetrometer’s estimate of the strength of the layered compacted seasonal snow. Such factors include the confining pressure, penetration energy, and the snow material properties, particularly the compaction of the snow undergoing penetration. A linear relationship between the penetration pressure and snow density was also established. The effect of age hardening on the penetration pressure was studied and the microstructure of the snow particles was observed through a microscope. These analyses showed that the cone penetrometer and data processing methodology applied in this study enable a rapid estimate of strength in seasonal snow, and may be applied in Antarctica after further modification. This would provide a scientific basis for the design of China’s Antarctic ice sheet airport.
  
  
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  Investigation of PMSE echoes characteristics using the discontinuous EISCAT UHF observation and its relation with space environment

  Abdur RAUF, Hailong LI, Safi ULLAH, Maoyan WANG, Lin MENG

  Advances in Polar Science. 2019, 30(2): 132-138. https://doi.org/10.13679/j.advps.2018.0041

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  The observations of Polar Mesosphere Summer Echoes (PMSE) were carried out using the sporadic data of EISCAT UHF radar during the summer season from 2004 to 2015. There were 25 h of PMSE echoes with EISCAT UHF radar. PMSE echoes were mostly observed only during the early morning and fore-noon time. Moreover, the PMSE echoes are positively correlated with Lyman α radiation, but the correlation is non-significant. The occurrence of PMSE echoes in the early morning and fore-noon time and there positive correlation with Lyman α radiation suggests that solar radiations might be one important factor for PMSE echoes in this study. Very weak positive, but statistically non-significant correlation is found between PMSE occurrence rate and the local geomagnetic K-indices. It is found that there is a matching between the variation in the occurrence rate of PMSE and noctilucent clouds (NLC) up to some extent and they are positively correlated. This positive correlation might support the earlier proposed idea about the role of ice particle size in producing PMSE echoes at higher frequencies.
  
  
Letters
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  Effects of vegetation on the structure and diversity of soil bacterial communities in the Arctic tundra

  Yue MA, Nengfei WANG, Shuang WANG, Wenbing HAN, Jie LIU, Yong YU, Li GUO, Guanpin YANG

  Advances in Polar Science. 2019, 30(2): 139-148. https://doi.org/10.13679/j.advps.2018.0040

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  The relatively simple vegetation of the Arctic tundra provides an ideal site in which to study the relationships between plants, bacterial communities and soil chemistry. Here, results of 16S rRNA gene sequencing of secondary Arctic brown soils collected from underneath colonies of Dryasoctopetala, Luzulaconfusa and Bistortavivipara in the Arctic tundra near Ny-Ålesund, Svalbard, Norway, reveal significant differences in bacterial communities related to soil environmental properties. Redundancy analysis shows that all measured geochemical factors were significant in structuring microbiomes, with strong correlations related to soil pH and organic matter contents. Vegetation is likely to affect the physical and chemical properties of the soil, which in turn affects the bacterial community and composition of the soil.
  
  
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  Early Cenozoic diorite and diabase from Doumer Island, Antarctic Peninsula: zircon U-Pb geochronology, petrogenesis and tectonic implications

  Jiawei CUI, Jianmin HU, Junling PEI, Hong CHEN, Xingxing DU, Lijie WEI​

  Advances in Polar Science. 2019, 30(2): 149-164. https://doi.org/10.13679/j.advps.2018.0036

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  In order to understand the petrogenesis and tectonic setting of diorite and diabase units on Doumer Island, Antarctic Peninsula, this paper reports new laser ablation—inductively coupled plasma—mass spectrometry (LA-ICP-MS) zircon U-Pb, geochemical, and Lu-Hf isotopic data for the magmatism. The diorite and diabase samples yielded zircon U-Pb ages of 55.4 ± 0.3 and 52.8 ± 0.4 Ma, respectively. These samples are enriched in the large ion lithophile elements and the light rare earth elements, and are depleted in the high field strength elements. The zircons in these samples yield Hf (t) values from 9.03 to 11.87 and model ages (TDM2) of 342–524 Ma. The major, trace, rare earth element (REE), and Hf isotopic data for the diorites indicate that these units were formed by the mixing of magmas generated by (a) the partial melting of mantle wedge material that experienced fluid-metasomatism in a subduction zone setting, and (b) the melting of juvenile crustal material induced by the upwelling of mantle-derived magmas in a subduction–collision setting. The diabase units contain higher total REE concentrations than the diorite, indicating they were derived from a different source region. These samples also have higher Mg# values and contain lower concentrations of Cr and Ni than the diorites, and have weakly negative Nb and Ta anomalies with Nb/Ta values of <3. The zircons in these samples yield Hf (t) values from 9.08 to 11.11 and model ages (TDM2) of 389–503 Ma. The major, trace, REE, and Hf isotopic compositions of the diabase units indicate that that they were derived from the mixing of depleted mantle-derived magmas with magmas generated by the melting of juvenile crustal material which was induced by the upwelling of the mantle into the crust. Overall the Cenozoic diorite and diabase on Doumer Island is related to subduction environment.