The Poleward Transport of Moisture and Clouds in the Antarctic

第6回極域科学シンポジウム[OM] 極域気水圏11月16日（月）　統計数理研究所 セミナー室2（D304

Automatic Weather Station (AWS) Program operated by the University of Wisconsin-Madison during the 2012-2013 field season: Challenges and Successes

ウィスコンシン大学マディソン校で推進している南極無人気象観測計画（Antarctic Automatic Weather Station（AWS）program）の，2012-2013年のフィールド調査および結果の概要を報告する．今期はAWS 観測網の歴史上，特異なシーズンであった．ロス島地域が温暖であったことは氷上滑走路の利用に影響を及ぼし，いくつかの設営面での制約に直面した． 柔軟な計画により，限られた条件下でAWS サービルを最大化し，自動観測ネットワークへの要求に対応する最善の手段をとることができた．This report reviews 2012-2013 field season activities of the University of Wisconsin-Madison＇s Antarctic Automatic Weather Station (AWS) program, summarizes the science that these sites are supporting, and outlines the factors that impact the number of AWS sites serviced in any given field season. The 2012-2013 austral summer season was unusual in the AWS network history. Challenges encountered include, but are not limited to, warmer than normal conditions in the Ross Island area impacting airfield operations, changes to logistical procedures, and competition for shared resources. A flexible work plan provides the best means for taking on these challenges while maximizing AWS servicing efforts under restricted conditions and meeting the need for routine servicing that maintaining an autonomous observing network demands

Atmospheric Meridional Moisture Flux over the Southern Ocean: A Story of the Amundsen Sea

AbstractThe Antarctic ice sheet constitutes the largest reservoir of freshwater on earth, representing tens of meters of sea level rise if it were to melt completely. However, because of the remote location of the continent and the concomitant sparse data coverage, much remains unknown regarding the climate variability in Antarctica and the surrounding Southern Ocean. This study uses the high-resolution ECMWF Interim Re-Analysis (ERA-Interim) data during 1979–2010 to calculate the meridional moisture transport associated with the mean circulation, planetary waves, and synoptic-scale systems. The resulting moisture flux, which is dominated by the synoptic scales, is largely consistent with results from theoretical assumptions and previous studies. Here, high interannual and regional variability in the total meridional moisture flux is found, with no significant trend over the last 30 years. Further, the variability of the meridional moisture flux cannot be explained by the southern annular mode or El Niño–Southern Oscillation, even in the Pacific sector. In addition, the Amundsen Sea sector experiences the highest variability in meridional moisture transport and reveals a statistically significant decrease in the moisture flux at synoptic scales along the coastal zone. These results suggest that the Amundsen Sea provides a window on the complex nature of atmospheric moisture transport in the high southern latitudes.</jats:p

The role of atmospheric rivers in anomalous snow accumulation in East Antarctica

© 2014. American Geophysical Union. Recent, heavy snow accumulation events over Dronning Maud Land (DML), East Antarctica, contributed significantly to the Antarctic ice sheet surface mass balance (SMB). Here we combine in situ accumulation measurements and radar-derived snowfall rates from Princess Elisabeth station (PE), located in the DML escarpment zone, along with the European Centre for Medium-range Weather Forecasts Interim reanalysis to investigate moisture transport patterns responsible for these events. In particular, two high-accumulation events in May 2009 and February 2011 showed an atmospheric river (AR) signature with enhanced integrated water vapor (IWV), concentrated in narrow long bands stretching from subtropical latitudes to the East Antarctic coast. Adapting IWV-based AR threshold criteria for Antarctica (by accounting for the much colder and drier environment), we find that it was four and five ARs reaching the coastal DML that contributed 74-80% of the outstanding SMB during 2009 and 2011 at PE. Therefore, accounting for ARs is crucial for understanding East Antarctic SMB.status: publishe

Physical and biogeochemical oceanography data from Conductivity, Temperature, Depth (CTD) rosette deployments during the Antarctic Circumnavigation Expedition (ACE).

***** Dataset abstract ***** This data set contains measurements from various sensors mounted on the Conductivity, Temperature, Depth (CTD) rosette that was deployed in the Southern Ocean during the Antarctic Circumnavigation Expedition (ACE). 63 CTD casts were carried out during three legs in the period 21st December 2016 to 16th March 2017, including one test cast and one failed cast, for which no data is available. Data include temperature, salinity, pressure, dissolved oxygen, oxygen saturation, chlorophyll-a concentration, backscatter, and photosynthetically active radiation (PAR) and reported are also the computed variables density, depth, and sound velocity. All data has been quality controlled and post-cruise calibrated, except for the oxygen data. Data is provided at 1 dbar pressure intervals for the up- and down-casts separately and as a merged bottle file when Niskin bottles were closed. This circumpolar data set provides insights into the circumpolar hydrography and biogeochemistry of the Southern Ocean during one austral summer season. ***** Dataset contents ***** For transparency, the raw files and files produced at the intermediate stages of data processing have been provided, in addition to the final processed files. Raw data files: - ace_ctd_raw_files.zip - includes raw files direct from instrument and XMLCON configuration files Intermediate files: - files output at each stage of the SeaBird processing Processed data files: - ace_ctd_CTD20190805CURRSGCMR - one final set of files for the complete sensor data; - ACE_BOTTLE20190807CURRSGCM_hy1.csv - a merged bottle file extracted from the sensor data is also provided Metadata: - range of files describing the CTD deployments, sensors, water sampling,  quality-checking and processing of the files. ***** Dataset license***** This physical and biogeochemical oceanography dataset is made available under the Creative Commons Attribution 4.0 International License (CC BY 4.0) whose full text can be found at https://creativecommons.org/licenses/by/4.0/  </p