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 ◽  
...  

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.

2000 ◽  
Vol 17 (3) ◽  
pp. 260-269 ◽  
Author(s):  
Marton G. Hidas ◽  
Michael G. Burton ◽  
Matthew A. Chamberlain ◽  
John W. V. Storey

AbstractThe Antarctic Plateau provides the best terrestrial sites for infrared (IR) and submillimetre (sub-mm) astronomy. In this paper we examine the relative importance of temperature, aerosol content and precipitable water vapour to determine which parameters have the greatest influence on atmospheric transmission and sky brightness. We use the atmospheric modelling program MODTRAN to model the observed sky spectrum at the South Pole from the near-IR to the sub-mm. We find that temperature and aerosol content determine the quality of near-IR observing conditions, aerosol content is the determining factor in the mid-IR up to 20 μm, while at longer wavelengths, including the sub-mm, it is the water vapour content that matters. Finding a location where aerosol levels are minimised is a key constraint in determining the optimum site on the Antarctic Plateau for an IR observatory.


2015 ◽  
Vol 3 (6) ◽  
pp. 3861-3895 ◽  
Author(s):  
P. Benevides ◽  
J. Catalao ◽  
P. M. A. Miranda

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.


Author(s):  
Houaria Namaoui ◽  
Salem Kahlouche ◽  
Ahmed Hafidh Belbachir

Remote sensing of atmospheric water vapour using GNSS and Satellite data has become an efficient tool in meteorology and climate research. Many satellite data have been increasingly used to measure the content of water vapour in the atmosphere and to characterize its temporal and spatial variations. In this paper, we have used observations from radiosonde data collected from three stations (Algiers, Bechar and Tamanrasset) in Algeria from January to December 2012 to evaluate Moderate Resolution Imaging Spectroradiometer (MODIS) total precipitable water vapour (PWV) products. Results show strong agreement between the total precipitable water contents estimated based on radiosondes observations and the ones measured by the sensor MODIS with the correlation coefficients in the range 0.69 to 0.95 and a mean bias, which does not exceed 1.5.  


MAUSAM ◽  
2021 ◽  
Vol 57 (2) ◽  
pp. 323-328
Author(s):  
R. K. GIRI ◽  
B. R. LOE ◽  
N. PUVIARSON ◽  
S. S. BHANDARI ◽  
R. K. SHARMA

Lkkj & ok;qeaMy esa ty ok"i dk forj.k LFkkfud :i ls vkSj dkfyd rkSj ij cgqr vf/kd ifjorZu’khy gksrk gSA ty ok"i dk forj.k vusdksa ok;qeaMyh; izfØ;kvksa esa izeq[k Hkwfedk fuHkkrk gSA dqy lekdfyr ty ok"i vFkok le:ih o"kkZ ty ok"i dk vkdyu Xykscy iksft’kfuax flLVe ¼th- ih- ,l-½ tsfuFk VksVy fMys ¼tsM- Vh- Mh-½ ds vk¡dM+ksa dh lgk;rk ls fd;k tk ldrk gSA blesa tsfuFk nzoLFkSfrd fMys ds eku dks funf’kZr fd;k x;k gS vkSj bls tsM- Vh- Mh- ls fudkyus ij tsfuFk vknzZ fMys ds vk¡dM+s izkIr gksaxsA vr% bl izdkj vkdfyr fd, x, tsM- MCY;w- Mh- ds eku ls izk;% yxkrkj ,e- ,e-  esa o"kkZ  ty ok"i dk irk pysxkA bl 'kks/k&i= esa th- ih- ,l- ds vk¡dM+ksa dk mi;ksx djrs gq, ubZ fnYyh ds fy, o"kZ 2003 ds 'khrdkyhu _rq vkSj Hkkjrh; foKku laLFkku ifj"kn] caxykSj ds dsanzksa ds fy, ,e- ,e- esa ih- MCY;w- oh- dk vkdyu djus dk iz;kl fd;k x;k gSA buls izkIr gq, ifj.kkeksa dk jsfM;kslkSUnsa vk¡dM+ksa ds lkFk lgh rkyesy ik;k x;k gSA The distribution of water vapour in atmosphere is highly spatial and temporal variable. It plays a key role in many atmospheric processes. The total integrated water vapour or equivalent precipitable water vapour (PWV) can be estimated with the help of Global Positioning System (GPS) Zenith Total Delay (ZTD) data. The value of Zenith Hydrostatic Delay (ZHD) is modeled and subtracting from ZTD will give Zenith wet delay (ZWD). Consequently, the estimated ZWD values will provide PWV in mm almost in a continuous manner. In this paper an attempt has been made for the estimation of PWV in mm during winter season 2003 for New Delhi and Indian Institute of Science (IISC), Bangalore stations using GPS data. The result shows fairly good agreement with the radio-sonde data. 


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