scholarly journals Antarctic atmospheric boundary layer observations with the Small Unmanned Meteorological Observer (SUMO)

2021 ◽  
Vol 13 (3) ◽  
pp. 969-982
Author(s):  
John J. Cassano ◽  
Melissa A. Nigro ◽  
Mark W. Seefeldt ◽  
Marwan Katurji ◽  
Kelly Guinn ◽  
...  

Abstract. Between January 2012 and June 2017 a small unmanned aerial system (sUAS), known as the Small Unmanned Meteorological Observer (SUMO), was used to observe the state of the atmospheric boundary layer in the Antarctic. During six Antarctic field campaigns, 116 SUMO flights were completed. These flights took place during all seasons over both permanent ice and ice-free locations on the Antarctic continent and over sea ice in the western Ross Sea. Sampling was completed during spiral ascent and descent flight paths that observed the temperature, humidity, pressure and wind up to 1000 m above ground level and sampled the entire depth of the atmospheric boundary layer, as well as portions of the free atmosphere above the boundary layer. A wide variety of boundary layer states were observed, including very shallow, strongly stable conditions during the Antarctic winter and deep, convective conditions over ice-free locations in the summer. The Antarctic atmospheric boundary layer data collected by the SUMO sUAS, described in this paper, can be retrieved from the United States Antarctic Program Data Center (https://www.usap-dc.org, last access: 8 March 2021). The data for all flights conducted on the continent are available at https://doi.org/10.15784/601054 (Cassano, 2017), and data from the Ross Sea flights are available at https://doi.org/10.15784/601191 (Cassano, 2019).

2020 ◽  
Author(s):  
John J. Cassano ◽  
Melissa A. Nigro ◽  
Mark W. Seefeldt ◽  
Marwan Katurji ◽  
Kelly Guinn ◽  
...  

Abstract. Between January 2012 and June 2017 a small unmanned aerial system (UAS), known as the Small Unmanned Meteorological Observer (SUMO), was used to observe the state of the atmospheric boundary layer in the Antarctic. During 6 Antarctic field campaigns 116 SUMO flights were completed. These flights took place during all seasons over both permanent ice and ice free locations on the Antarctic continent and over sea ice in the western Ross Sea. Sampling was completed during spiral ascent and descent flight paths that observed the temperature, humidity, pressure and wind up to 1000 m above ground level and sampled the entire depth of the atmospheric boundary layer as well as portions of the free atmosphere above the boundary layer. A wide variety of boundary layer states were observed including very shallow, strongly stable conditions during the Antarctic winter and deep, convective conditions over ice free locations in the summer. The Antarctic atmospheric boundary layer data collected by the SUMO sUAS, described in this paper, can be retrieved from the United States Antarctic Program Data Center (https://www.usap-dc.org). The data for all flights conducted on the continent are available at https://www.usap-dc.org/view/dataset/601054 (Cassano 2017; https://doi.org/10.15784/601054) and data from the Ross Sea flights, are available at https://www.usap-dc.org/view/dataset/601191 (Cassano 2019; https://doi.org/10.15784/601191).


2021 ◽  
Author(s):  
Hannah Dawson ◽  
Adele Morrison ◽  
Veronica Tamsitt ◽  
Matthew England

<p><span xml:lang="EN-US" data-contrast="auto"><span>The Antarctic margin is surrounded by two westward flowing currents: the Antarctic Slope Current and the Antarctic Coastal Current. The former influences key processes near the Antarctic margin by regulating the flow of heat and nutrients onto and off the continental shelf, while together they </span></span><span xml:lang="EN-US" data-contrast="auto"><span>advect</span></span><span xml:lang="EN-US" data-contrast="auto"><span> nutrients, biological organisms, and temperature and salinity anomalies around the coastline, providing a connective link between different shelf regions. However, the extent to which these currents transport water from one sector of the continental shelf to another, and the timescales over which this occurs, remain poorly understood. Concern that crucial water formation sites around the Antarctic coastline could respond to non-local freshwater forcing </span></span><span><span xml:lang="EN-US" data-contrast="auto"><span>from ice shel</span></span></span><span><span xml:lang="EN-US" data-contrast="auto"><span>f meltwater</span></span></span> <span xml:lang="EN-US" data-contrast="auto"><span>motivates a more thorough understanding of zonal connectivity around Antarctica. In this study, we use daily velocity fields from a global high-resolution ocean-sea ice model, combined with the <span>Lagrangian</span> tracking software Parcels, to investigate the pathways and timescales connecting different regions of the Antarctic continental shelf<span> with a view to understanding</span><span> the timescales of meltwater transport around the continent</span>. Virtual particles are released over the continental shelf, poleward of the 1000 <span>metre</span> isobath, and are tracked for 20 years. Our results show a strong seasonal cycle connecting different sectors of the Antarctic continent, with more particles arriving further downstream during winter than during summer months. Strong advective links exist between West Antarctica and the Ross Sea while shelf geometry in some other regions acts as barriers to transport. We also highlight the varying importance of the Antarctic Slope Current and Antarctic Coastal Current in connecting different sectors of the coastline. Our results help to improve our understanding of circum-Antarctic connectivity <span>and the timescales </span><span>of meltwater transport from source regions to downstream </span><span>shelf locations. </span><span>Further</span><span>more, t</span><span>he timescales and pathways we </span><span>present </span><span>p</span>rovide a baseline from which to assess long-term changes in Antarctic coastal circulation due to local and remote forcing.<br></span></span></p>


2020 ◽  
Vol 77 (7) ◽  
pp. 2375-2392
Author(s):  
Lei Liu ◽  
Fei Hu

AbstractThe intermittency of atmospheric turbulence plays an important role in the understanding of particle dispersal in the atmospheric boundary layer and in the statistical simulation of high-frequency wind speed in various applications. There are two kinds of intermittency, namely, the magnitude intermittency (MI) related to non-Gaussianity and the less studied clusterization intermittency (CI) related to long-term correlation. In this paper, we use a 20 Hz ultrasonic dataset lasting for 1 month to study CI of turbulent velocity fluctuations at different scales. Basing on the analysis of return-time distribution of telegraphic approximation series, we propose to use the shape parameter of the Weibull distribution to measure CI. Observations of this parameter show that contrary to MI, CI tends to weaken as the scale increases. Besides, significant diurnal variations, showing that CI tends to strengthen during the daytime (under unstable conditions) and weaken during the nighttime (under stable conditions), are found at different observation heights. In the convective boundary layer, the mixed-layer similarity is found to scale the CI exponent better than the Monin–Obukhov similarity. At night, CI is found to vary less with height in the regime with large mean wind speeds than in the regime with small mean wind speeds, according to the hockey-stick theory.


Polar Record ◽  
1994 ◽  
Vol 30 (174) ◽  
pp. 189-192 ◽  
Author(s):  
Colin M. Harris

AbstractAs a result of new provisions in the Protocol on Environmental Protection to the Antarctic Treaty a number of countries are reviewing the management plans for protected areas in Antarctica. The United States and New Zealand have initiated a review of the 15 existing sites in the Ross Sea region, using an independent party, the International Centre for Antarctic Information and Research, to facilitate and coordinate the process. Management provisions are being revised to comply with the Protocol, and improved maps for the sites are being prepared using Geographical Information Systems. Visits in 1993/94 gathered field information, and thus far two sites have had new plans drafted: these are proceeding through the international review process. Input and comment is invited from interested parties with experience in these areas.


2014 ◽  
Vol 59 (11) ◽  
pp. 999-1005 ◽  
Author(s):  
JingFeng LIU ◽  
ChangGui LU ◽  
ChuanJin LI ◽  
CunDe XIAO ◽  
Liang FU ◽  
...  

Polar Record ◽  
2011 ◽  
Vol 49 (1) ◽  
pp. 50-61
Author(s):  
Stephen Hicks ◽  
Bryan Storey ◽  
Philippa Mein Smith

ABSTRACTWhen the Commonwealth Trans-Antarctic Expedition 1955–1958 advance party sailed from the Millwall Docks in November 1955, bound for the Weddell Sea, their departure was the product of five years of intensive effort on the part of Vivian Fuchs to achieve the first overland crossing of the Antarctic continent. This paper investigates the many obstacles that had to be overcome leading up to Theron sailing and explains the manner in which they were overcome by the Fuchs-Wordie-Clifford triumvirate. The British Foreign Office was particularly opposed to the expedition with the office's focus on sovereignty rather than science while an alternative proposal from Duncan Carse raised a unique set of difficulties. The withdrawal from involvement by the Scott Polar Research Institute Director, Colin Bertram, indicated further disaffection. Most important, if political and financial goals were to be met, was the need for participation by several Commonwealth countries of which New Zealand was the essential partner. Fortunately, the vigorous efforts of a few Antarctic enthusiasts in New Zealand were successful in moving their government to assert its long dormant position in the Ross Dependency. New Zealand's commitment turned the tide of commonwealth apathy towards the TAE. Although the TAE preceded the IGY, events, including the dominating IGY presence of the United States, caused the two projects to become tightly interwoven. For these reasons the years leading up to the departure of Theron were as intriguing as the crossing journey itself.


Polar Record ◽  
1960 ◽  
Vol 10 (64) ◽  
pp. 3-10 ◽  
Author(s):  
G. de Q. Robin

The art, science and sport of conducting scientific traverses across the Antarctic continent has advanced so rapidly during the past decade that we are making considerable progress towards understanding the main characteristics of that continent and its ice mantle. Many reports of recent work are provisional, so some changes of detail in the following account may eventually prove necessary. Nevertheless, some major features are now well established, such as the great depth of the subglacial floor to the east of the Ross Sea, and the observations that show considerable sections of the rock of East Antarctica† to be above sea level. On the other hand, the past glaciological history of the continent and the state of the present mass balance of the ice sheet still need much more investigation before we can be satisfied with the answers. The continued activity in Antarctica should result in our knowledge of the continent advancing much further during the coming decade.


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