scholarly journals Millimetre Astronomy from the High Antarctic Plateau: Site Testing at Dome C

1999 ◽  
Vol 16 (2) ◽  
pp. 167-174 ◽  
Author(s):  
L. Valenziano ◽  
G. Dall'Oglio
Keyword(s):  
Wind Speed ◽  
Meteorological Data ◽  
Large Fraction ◽  
Precipitable Water ◽  
South Pole ◽  
Site Testing ◽  
The South ◽  
Precipitable Water Vapour ◽  
Average Wind Speed ◽  
Antarctic Plateau

AbstractPreliminary site testing results at Dome C (Antarctica) are presented, using both Automatic Weather Station (AWS) meteorological data (1986–1993) and Precipitable Water Vapour (PWV) measurements made by the authors. A comparison with the South Pole and other sites is made. The South Pole is a well established astrophysical observing site, where extremely good conditions are reported for a large fraction of time during the year. Dome C, where Italy and France are building a new scientific station, is a potential observing site in the millimetre and submillimetre range. AWS are operating at both sites and they have been continuously monitoring temperature, pressure and wind speed and direction for more than ten years. Site testing instruments are already operating at the South Pole (AASTO, Automated Astrophysical Site-Testing Observatory), while light experiments have been running at Dome C (APACHE, Antarctic Plateau Anisotropy CHasing Experiment) during summertime. A direct comparison between the two sites is planned in the near future, using the AASTO. The present analysis shows that the average wind speed is lower at Dome C (∼1 ms−1) than at the South Pole (∼2 ms−1), while temperature and PWV are comparable.

scholarly journals Submillimeter Site Testing at Dome C, Antarctica

2004 ◽  
Vol 21 (3) ◽  
pp. 256-263 ◽  
Author(s):  
Paolo G. Calisse ◽  
Michael C. B. Ashley ◽  
Michael G. Burton ◽  
Michael A. Phillips ◽  
John W. V. Storey ◽  
...  
Keyword(s):  
South Pole ◽  
Site Testing ◽  
The South ◽  
Atmospheric Opacity ◽  
Antarctic Plateau ◽  
Under Construction ◽  
The Antarctic ◽  
Better Than

AbstractWe have developed a 350 μm radiometer to perform automated site testing in remote regions of Antarctica. In summer 2000–2001 the instrument operated at Concordia, a new station under construction at Dome C on the Antarctic Plateau. We present the results, and compare them with the atmospheric opacity measured at the South Pole in the same five-week period. During these five weeks, observing conditions at Dome C were, on average, substantially better than those at the South Pole.

scholarly journals On the inclusion of GPS precipitable water vapour in the nowcasting of rainfall

2015 ◽  
Vol 3 (6) ◽  
pp. 3861-3895 ◽  
Author(s):  
P. Benevides ◽  
J. Catalao ◽  
P. M. A. Miranda
Keyword(s):  
Water Vapour ◽  
Meteorological Data ◽  
Simple Algorithm ◽  
Precipitable Water ◽  
False Alarms ◽  
Precipitable Water Vapour ◽  
Temporal Behaviour ◽  
Nearby Region ◽  
Single Station ◽  
Rain Events

Abstract. The temporal behaviour of Precipitable Water Vapour (PWV) retrieved from GPS delay data is analysed in a number of case studies of intense precipitation in the Lisbon area, in the period 2010–2012, and in a continuous annual cycle of 2012 observations. Such behaviour is found to correlate positively with the probability of precipitation, especially in cases of severe rainfall. The evolution of the GPS PWV in a few stations is analysed by a least-squares fitting of a broken line tendency, made by a temporal sequence of ascents and descents over the data. It is found that most severe rainfall event occurs in descending trends after a long ascending period, and that the most intense events occur after steep ascents in PWV. A simple algorithm, forecasting rain in the 6 h after a steep ascent of the GPS PWV in a single station is found to produce reasonable forecasts of the occurrence of precipitation in the nearby region, without significant misses in what concerns larger rain events, but with a substantial amount of false alarms. It is suggested that this method could be improved by the analysis of 2-D or 3-D time varying GPS PWV fields, or by its joint use with other meteorological data relevant to nowcast precipitation.

The flourishing forests of Antarctica

2007 ◽  
Author(s):  
David Beerling
Keyword(s):  
Sea Level ◽  
The Other ◽  
Cold Weather ◽  
South Pole ◽  
The South ◽  
Altitude Sickness ◽  
Antarctic Plateau ◽  
The Times ◽  
The Antarctic ◽  
As If

By arriving at the South Pole on 14 December 1911, the Norwegian explorer Roald Amundsen (1872–1928) reached his destination over a month ahead of the British effort led by Captain Robert Falcon Scott (1868–1912). As Scott’s party approached the South Pole on 17 January 1912, they were devastated to see from afar the Norwegian’s black flag. On arrival, they discovered the remains of his camp with ski and sledge tracks, and numerous dog footprints. Amundsen, it turned out, had used dogs and diversionary tactics to secure victory while the British team had man-hauled their sledges. These differences were not lost on The Times in London, which marked the achievement with muted praise, declaring it ‘not quite in accordance with the spirit of fair and open competition which hitherto marked Antarctic exploration’. Exhausted, Scott and his men spent time the following day making scientific observations around the Pole, erected ‘our poor slighted Union Jack’, and photographed themselves in front of it (Plate 11). Lieutenant Bowers took the picture by pulling a string to activate the shutter. It is perhaps the most well known, and at the same time the saddest picture, of the entire expedition—a poignant image of the doomed party, all of whom look utterly fed up as if somehow sensing the fate awaiting them. The cold weather, icy wind, and dismal circumstances led Scott to acerbically remark in his diary: ‘Great god! This is an awful place and terrible enough to have laboured to it without the reward of priority.’ By this time, the party had been hauling their sledges for weeks, and all the men were suffering from dehydration, owing to fatigue and altitude sickness from being on the Antarctic plateau that sits nearly 3000m above sea level. Three of them, Captain Oates, Seaman Evans, and Bowers, were badly afflicted with frostbitten noses and cheeks. Ahead lay the return leg, made all the more unbearable by the crippling psychological blow of knowing they had been second to the Pole. After a gruelling 21-day trek in bitterly cold summit winds, the team reached their first cache of food and fuel, covering the distance six days faster than it had taken them to do the leg in the other direction.

scholarly journals δD And δ18O In South Pole Snow: Further Comparison With Meteorological Data and The Record From the Last Millennium (Abstract)

1988 ◽  
Vol 11 ◽  
pp. 208
Author(s):  
J. R. Petit ◽  
J. Jouzel ◽  
J. C. White ◽  
Qian Qiu-yu ◽  
M. Legrand ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Water Cycle ◽  
Meteorological Data ◽  
Ice Core ◽  
Snow Accumulation ◽  
South Pole ◽  
The South ◽  
Isotope Record ◽  
Δd And Δ18o ◽  
Isotope Content

The stable-isotope content of precipitation (δD and δ18O) is governed by the successive fractionation processes which occur during the atmospheric water cycle. As a result there is, in polar areas, a well-obeyed and theoretically well-understood linear relationship between the mean istopic content of snow and its mean temperature of formation. This relationship is well documented on a spatial scale but poorly known for a given site on a temporal basis, the main reason being that relatively long-term and sufficiently detailed meteorological data are only available for a few polar sites. The South Pole appears to be a suitable place for such a study because: (i) snow accumulation is high enough (∼20 cm of snow per year), thus reducing the possibility that annual layers will be lost as a result of wind; (ii) seasonal variation in isotope content is still preserved in snow up to 50 years old; (iii) meteorological data are available from the time the station was opened in 1957. Our previous studies of surface and recently deposited snow at the South Pole were very encouraging in this respect; they have been extended with a two-fold purpose: (i) to test the geographical representativity of the isotope record by comparing results from various cores taken within a 10 km radius of the station. The cores are dated by various techniques, such as stratigraphy, seasonal variation in isotopic content, beta-radioactivity fall-out layers, and detection by solid conductivity measurements of the high “spike” which is thought to correspond to the 1815 Tambora eruption; (ii) to discuss the South Pole isotope record over the last 1000 years as recovered from a 127 m deep ice core.

scholarly journals Site characteristics of the high Antarctic plateau

2012 ◽  
Vol 8 (S288) ◽  
pp. 15-24
Author(s):  
Michael C. B. Ashley
Keyword(s):  
South Pole ◽  
Site Testing ◽  
Antarctic Plateau ◽  
Site Characteristics

AbstractA brief review is given of the major results from the last twenty years of astronomical site-testing in Antarctica. Suggestions are made for how to resolve some outstanding questions, such as the infrared sky background at Antarctic sites other than South Pole station.

Where is Ridge A?

2012 ◽  
Vol 8 (S288) ◽  
pp. 304-305
Author(s):  
Geoff Sims ◽  
Craig Kulesa ◽  
Michael C. B. Ashley ◽  
Jon S. Lawrence ◽  
Will Saunders ◽  
...  
Keyword(s):  
Water Vapour ◽  
Humidity Sensor ◽  
Precipitable Water ◽  
Dome A ◽  
Precipitable Water Vapour ◽  
Antarctic Plateau ◽  
Terahertz Transmission

AbstractFirst identified in 2009 as the site with the lowest precipitable water vapour (PWV) and best terahertz transmission on Earth, “Ridge A” is located approximately 150 km south of Dome A, Antarctica. We use three years of data from the Microwave Humidity Sensor (MHS) on the NOAA-18 satellite and recent ground-based measurements from Ridge A to probe the PWV variations and stability over the high Antarctic plateau.

scholarly journals Effect of meteorological factors on the activity of influenza in Chongqing, China, 2012–2019

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0246023
Author(s):  
Li Qi ◽  
Tian Liu ◽  
Yuan Gao ◽  
Dechao Tian ◽  
Wenge Tang ◽  
...  
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Meteorological Factors ◽  
Meteorological Data ◽  
Warning System ◽  
Absolute Humidity ◽  
Influenza Surveillance ◽  
Average Wind Speed ◽  
Mean Temperature ◽  
Influenza Activity

Background The effects of multiple meteorological factors on influenza activity remain unclear in Chongqing, the largest municipality in China. We aimed to fix this gap in this study. Methods Weekly meteorological data and influenza surveillance data in Chongqing were collected from 2012 to 2019. Distributed lag nonlinear models (DLNMs) were conducted to estimate the effects of multiple meteorological factors on influenza activity. Results Inverted J-shaped nonlinear associations between mean temperature, absolute humidity, wind speed, sunshine and influenza activity were found. The relative risks (RRs) of influenza activity increased as weekly average mean temperature fell below 18.18°C, average absolute humidity fell below 12.66 g/m3, average wind speed fell below 1.55 m/s and average sunshine fell below 2.36 hours. Taking the median values as the references, lower temperature, lower absolute humidity and windless could significantly increase the risks of influenza activity and last for 4 weeks. A J-shaped nonlinear association was observed between relative humidity and influenza activity; the risk of influenza activity increased with rising relative humidity with 78.26% as the break point. Taking the median value as the reference, high relative humidity could increase the risk of influenza activity and last for 3 weeks. In addition, we found the relationship between aggregate rainfall and influenza activity could be described with a U-shaped curve. Rainfall effect has significantly higher RR than rainless effect. Conclusions Our study shows that multiple meteorological factors have strong associations with influenza activity in Chongqing, providing evidence for developing a meteorology-based early warning system for influenza to facilitate timely response to upsurge of influenza activity.

Characteristics of the wind regime of Libya based on NCEP / NCAR reanalysis data and surface weather observations

2020 ◽  
Vol 101-102 (3-4) ◽  
pp. 26-32
Author(s):  
Ellina Agayar ◽  
Ali Saleh Abudawah
Keyword(s):  
Wind Speed ◽  
Wind Field ◽  
General Circulation ◽  
Meteorological Data ◽  
Surface Wind ◽  
Surface Wind Speed ◽  
Reanalysis Data ◽  
Average Wind Speed ◽  
Weather Observations ◽  
Surface Weather

The surface wind field are formed by the interaction of general circulation mechanisms with the local physical, geographical and climatic characteristics of the region. The success of the implementation of the different weather models is based on the representativeness of the initial information. The paper presents the results of comparing meteorological data, such as the average monthly speed and direction of the surface wind, from the NCEP / NCAR reanalysis archive with data of surface weather observations for the period from 2015 to 2019. Considering the difficulty of obtaining data, the absence of continuous observations at many meteorological stations in Libya, it was decided to analyze the most complete series of observations for the last period and compare it with the model data of reanalysis. Meteorological stations are located in different geographic regions of Libya (Derna, Zuara, Efren, Misurata, Godames, Jagbub, El-Kufra and Ghat). Based on the monthly average values of the surface wind velocity components for past five years, was done a study of the intrannual structure of the wind field over the territory of Libya and maps of the wind field for this period were constructed. The obtained results of comparison of the NCEP / NCAR reanalysis data with Surface weather observations showed a relatively good agreement between the observed and calculated wind. Noted that the wind, according to NCEP data, is some weaker than observed at the stations. The main reasons for this are the complexity and diversity of the topography around the stations, as well as the representativeness between gridded data and meteorological measurements. Analysis of the distribution of the average monthly wind speed over the territory of Libya indicates a tendency for an increase in the surface wind speed from the southwest to the northeast, both as according to the NCEP / NCAR reanalysis data, where the average wind speed doesn’t exceed 4.7 m/s, and according to actual observations 6.7 m/s.

A Troposphere Constraint Method To Improve PPP Ambiguity-Resolved Height Solution

2013 ◽  
Vol 67 (2) ◽  
pp. 249-262 ◽  
Author(s):  
Junbo Shi ◽  
Yang Gao
Keyword(s):  
Meteorological Data ◽  
A Priori ◽  
Precipitable Water ◽  
Conventional Approach ◽  
Integer Ambiguity ◽  
Convergence Time ◽  
Precipitable Water Vapour ◽  
Positioning Accuracy ◽  
Constraint Method ◽  
Decoupled Clock Model

Integer ambiguity resolution is able to improve positioning accuracy and reduce convergence time in Precise Point Positioning (PPP). Although significantly improved horizontal positioning accuracy has been demonstrated, the height solution improvement is found to be less significant, and improving this requires further investigation. In this paper, a troposphere constraint method using precise troposphere corrections is proposed to improve the PPP ambiguity-resolved height solution. This is different from the conventional approach that typically applies meteorological data to calculate the a priori troposphere delay and estimates the residual troposphere delay. The effects of the troposphere delay on PPP ambiguity-resolved height solutions are first studied. Numerical analysis is conducted to ambiguity-resolved positioning results based on the decoupled clock model and hourly Global Positioning System (GPS) observations from a Canadian PPP-inferred troposphere precipitable water vapour system. The results show that by using the proposed method the PPP ambiguity-resolved height accuracy can be further improved to 3·86 cm compared to 5·32 cm using the conventional approach.

scholarly journals On the inclusion of GPS precipitable water vapour in the nowcasting of rainfall

2015 ◽  
Vol 15 (12) ◽  
pp. 2605-2616 ◽  
Author(s):  
P. Benevides ◽  
J. Catalao ◽  
P. M. A. Miranda
Keyword(s):  
Water Vapour ◽  
Meteorological Data ◽  
Simple Algorithm ◽  
Precipitable Water ◽  
False Alarms ◽  
Precipitable Water Vapour ◽  
Temporal Behaviour ◽  
Nearby Region ◽  
Single Station ◽  
Rain Events

Abstract. The temporal behaviour of precipitable water vapour (PWV) retrieved from GPS delay data is analysed in a number of case studies of intense precipitation in the Lisbon area, in the period 2010–2012 and in a continuous annual cycle of 2012 observations. Such behaviour is found to correlate positively with the probability of precipitation, especially in cases of severe rainfall. The evolution of the GPS PWV in a few stations is analysed by a least-squares fitting of a broken line tendency, made by a temporal sequence of ascents and descents over the data. It is found that most severe rainfall events occur in descending trends after a long ascending period and that the most intense events occur after steep ascents in PWV. A simple algorithm, forecasting rain in the 6 h after a steep ascent of the GPS PWV in a single station, is found to produce reasonable forecasts of the occurrence of precipitation in the nearby region, without significant misses in what concerns larger rain events, but with a substantial amount of false alarms. It is suggested that this method could be improved by the analysis of 2-D or 3-D time-varying GPS PWV fields or by its joint use with other meteorological data relevant to nowcast precipitation.

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