scholarly journals IPWV estimation and data quality analysis from different GNSS antenna

MAUSAM ◽  
2021 ◽  
Vol 63 (1) ◽  
pp. 77-88
Author(s):  
J.K.S. YADAV ◽  
R.K. GIRI ◽  
L.R. MEENA
Keyword(s):  
Data Quality ◽  
Signal Strength ◽  
Precipitable Water ◽  
Satellite System ◽  
Quality Analysis ◽  
Data Quality Control ◽  
Positional Accuracy ◽  
Precipitable Water Vapour ◽  
Cycle Slips ◽  
Ring Antenna

Global Navigation Satellite System (GNSS) is widely used now days in variety of applications. The observation file for the near realtime estimation of Integrated Precipitable Water Vapour (IPWV) received at the ground-based receiver is mixed with ambiguities. Multi-path effects affect the positional accuracy as well as range from satellite to ground based receiver of the system. The designing of the antenna suppress the effect of multi-path, cycle slips, number of observations, and signal strength and data gaps within the data streams. This paper presents the preliminary data quality control findings of the Patch antenna (LeicaX1202), 3D Choke ring antenna (LeicaAR25 GNSS) and Trimble Zephyr antenna (TRM 39105.00). The results shows that choke ring antenna have least gaps in the data, cycle slips and multi-path effects along with improvement in IPWV. The signal strength and the number of observations are more in case of 3D choke ring antenna.

scholarly journals Comparison of GNSS and INSAT-3D sounder retrieved precipitable water vapour and validation with the GPS Sonde data over Indian Subcontinent

MAUSAM ◽  
2021 ◽  
Vol 71 (1) ◽  
pp. 1-10
Author(s):  
YADAV RAMASHRAY ◽  
PUVIARASAN N ◽  
GIRI R K ◽  
TOMAR C S ◽  
SINGH VIRENDRA
Keyword(s):  
Water Vapour ◽  
Indian Subcontinent ◽  
India Meteorological Department ◽  
Precipitable Water ◽  
Satellite System ◽  
Atmospheric Water ◽  
Precipitable Water Vapour ◽  
Vertical Column ◽  
Atmospheric Water Vapour ◽  
Channel Sounder

Precipitable water vapour (PWV) plays a key role in the atmospheric processes from climate change to micrometeorology. Its distribution and quantity are critical for the description of state and evaluation of the atmosphere in NWP model. Lack of precise and continuous water vapour data is one of the major error sources in short term forecast of precipitation. The task of accurately measuring atmospheric water vapour is challenging. Conventional in situ measurements of atmospheric water vapour is provided by GPS Sonde humidity sensors profile twice a day at 0000 and 1200 UTC mainly from limited land regions. In recent years India Meteorological Department (IMD) is computing PWV from 19 channel sounder of INSAT-3D in three layers 1000-900 hPa, 900-700 hPa and 700-300 hPa and total PWV in the vertical column of atmosphere stretching from surface to about 100 hPa under cloud free condition. These data most commonly were validated using spatially and temporally collocated GPS Sonde measurements. In this paper, INSAT-3D satellite retrieved PWV data are validated with column integrated PWV estimates from a network of ground based Global Navigation Satellite System (GNSS) over Indian subcontinent. The PWV retrieved by INSAT-3D sounder platform is very promising, being in a good agreement with the GNSS data recorded over India for the period June, 2017 to May, 2018. The root-mean-square (rms) differences of 5.4 to 7.1 mm, bias of -4.7 to +2.1 mm and correlations coefficient of 0.79 to 0.92 was observed between INSAT-3D and GNSS PWV. The correlations coefficient between GPS Sonde and GNSS derived PWV ranges from 0.85 to 0.98.

scholarly journals Spatial interpolation techniques for a near real-time mapping of pressure and temperature data

2016 ◽  
Author(s):  
Ilaria Ferrando ◽  
Pierluigi De Rosa ◽  
Bianca Federici ◽  
Domenico Sguerso
Keyword(s):  
Real Time ◽  
Physical Model ◽  
Digital Terrain Model ◽  
Precipitable Water ◽  
Satellite System ◽  
Total Delay ◽  
Local Pressure ◽  
Precipitable Water Vapour ◽  
Using Data ◽  
Global Navigation Satellite

Among the different techniques for atmosphere monitoring, the GNSS (Global Navigation Satellite System) can provide an innovative contribution (Bevis et al.,1992; Crespi et al., 2004; Sguerso et al., 2013, 2015). The Laboratory of Geomatics, Geodesy and GIS of the University of Genoa has identified a GIS procedure and a simplified physical model to monitor the Precipitable Water Vapour (PWV) content, using data measured by existing infrastructures. The starting points are local estimations of Zenith Total Delay (ZTD) from a GNSS Permanent Stations (PSs) network, a Digital Terrain Model (DTM) and local Pressure (P) and Temperature (T) measurements (Sguerso et al., 2014; Ferrando et al., 2016). The present paper shows the study of the most appropriate interpolation technique for P and T data to create PWV maps in a quick, stable and automatic way, to support the monitoring of intense meteorological events for both a posteriori and near real-time applications. The resulting P and T maps were compared to meteorological re-analysis, to check the reliability of the simplified physical model. Additionally, the Regression Kriging (RK) was employed to evaluate the data correlation with elevation and to study the applicability of the technique.

scholarly journals Water Vapour Assessment Using GNSS and Radiosondes over Polar Regions and Estimation of Climatological Trends from Long-Term Time Series Analysis

2021 ◽  
Vol 13 (23) ◽  
pp. 4871
Author(s):  
Monia Negusini ◽  
Boyan H. Petkov ◽  
Vincenza Tornatore ◽  
Stefano Barindelli ◽  
Leonardo Martelli ◽  
...  
Keyword(s):  
Water Vapour ◽  
Correlation Coefficients ◽  
Arctic Region ◽  
Precipitable Water ◽  
Satellite System ◽  
The Arctic ◽  
Polar Regions ◽  
Precipitable Water Vapour ◽  
Water Vapour Content

The atmospheric humidity in the Polar Regions is an important factor for the global budget of water vapour, which is a significant indicator of Earth’s climate state and evolution. The Global Navigation Satellite System (GNSS) can make a valuable contribution in the calculation of the amount of Precipitable Water Vapour (PW). The PW values retrieved from Global Positioning System (GPS), hereafter PWGPS, refer to 20-year observations acquired by more than 40 GNSS geodetic stations located in the polar regions. For GNSS stations co-located with radio-sounding stations (RS), which operate Vaisala radiosondes, we estimated the PW from RS observations (PWRS). The PW values from the ERA-Interim global atmospheric reanalysis were used for validation and comparison of the results for all the selected GPS and RS stations. The correlation coefficients between times series are very high: 0.96 for RS and GPS, 0.98 for RS and ERA in the Arctic; 0.89 for RS and GPS, 0.97 for RS and ERA in Antarctica. The Root-Mean-Square of the Error (RMSE) is 0.9 mm on average for both RS vs. GPS and RS vs. ERA in the Arctic, and 0.6 mm for RS vs. GPS and 0.4 mm for RS vs. ERA in Antarctica. After validation, long-term trends, both for Arctic and Antarctic regions, were estimated using Hector scientific software. Positive PWGPS trends dominate at Arctic sites near the borders of the Atlantic Ocean. Sites located at higher latitudes show no significant values (at 1σ level). Negative PWGPS trends were observed in the Arctic region of Greenland and North America. A similar behaviour was found in the Arctic for PWRS trends. The stations in the West Antarctic sector show a general positive PWGPS trend, while the sites on the coastal area of East Antarctica exhibit some significant negative PWGPS trends, but in most cases, no significant PWRS trends were found. The present work confirms that GPS is able to provide reliable estimates of water vapour content in Arctic and Antarctic regions too, where data are sparse and not easy to collect. These preliminary results can give a valid contribution to climate change studies.

scholarly journals Spatial interpolation techniques for a near real-time mapping of Pressure and Temperature data

2016 ◽  
Author(s):  
Ilaria Ferrando ◽  
Pierluigi De Rosa ◽  
Bianca Federici ◽  
Domenico Sguerso
Keyword(s):  
Real Time ◽  
Physical Model ◽  
Digital Terrain Model ◽  
Precipitable Water ◽  
Satellite System ◽  
Total Delay ◽  
Local Pressure ◽  
Precipitable Water Vapour ◽  
Using Data ◽  
Global Navigation Satellite

Among the different techniques for atmosphere monitoring, the GNSS (Global Navigation Satellite System) can provide an innovative contribution (Bevis et al.,1992; Crespi et al., 2004; Sguerso et al., 2013, 2015). The Laboratory of Geomatics, Geodesy and GIS of the University of Genoa has identified a GIS procedure and a simplified physical model to monitor the Precipitable Water Vapour (PWV) content, using data measured by existing infrastructures. The starting points are local estimations of Zenith Total Delay (ZTD) from a GNSS Permanent Stations (PSs) network, a Digital Terrain Model (DTM) and local Pressure (P) and Temperature (T) measurements (Sguerso et al., 2014; Ferrando et al., 2016). The present paper shows the study of the most appropriate interpolation technique for P and T data to create PWV maps in a quick, stable and automatic way, to support the monitoring of intense meteorological events for both a posteriori and near real-time applications. The resulting P and T maps were compared to meteorological re-analysis, to check the reliability of the simplified physical model. Additionally, the Regression Kriging (RK) was employed to evaluate the data correlation with elevation and to study the applicability of the technique.

Investigation of Foehn Events on South Georgia Island using Meteorological Surface Data and GNSS Precipitable Water Vapour

2021 ◽  
Author(s):  
Eshetu Erkihune ◽  
Addisu Hunegnaw ◽  
Felix Norman Teferle
Keyword(s):  
Water Vapour ◽  
Meteorological Data ◽  
Precipitable Water ◽  
Satellite System ◽  
Data Sets ◽  
Precipitable Water Vapour ◽  
Near Surface ◽  
South Georgia ◽  
Circumpolar Current ◽  
Global Navigation Satellite

<p>As one of the most important components of the global hydrologic cycle, atmospheric water vapor shows significant variability in both space and time over a large range of scales. This variability results from the interactions of many different factors, including topography and the presence of specific atmospheric processes. One of the key regions for affecting global climatic variations lies in the sub-Antarctic zone over the Southern Ocean with its Antarctic Circumpolar Current and the associated Antarctic Convergence. There, in this cold and maritime region, lies South Georgia Island with its weather and climate being largely affected by both the dominating ocean currents and the westerly winds in this zone. While the island forms an important outpost for various surface observations in this largely under sampled and extremely remote region, it also forms a barrier for these winds due to its high topography. This, in turn, leads to various local meteorological phenomena, such as warm Foehn winds, which have a significant impact on the near-surface meteorology and contribute to the accelerated glacier retreat observed for the northeast of the island.</p><p>Surface meteorological data have been available for several stations near King Edward Point (KEP) in South Georgia for much of the 20<sup>th</sup> century. Since 2013 and 2014, Global Navigation Satellite System (GNSS) data have been available at five locations around the periphery of the island. In this study, we investigate the consistency between the different surface meteorological data sets and along with GNSS Precipitable Water Vapour we use these to analyse historic Foehn events.</p><p> </p>

scholarly journals Inter-comparison of retrievals of Integrated Precipitable Water Vapour IPWV) made by INSAT-3DR satellite-borne Infrared Radiometer Sounding and CAMS reanalysis data with ground-based Indian GNSS data

2021 ◽  
Author(s):  
Ramashray Yadav ◽  
Ram Kumar Giri ◽  
Virendra Singh
Keyword(s):  
Water Vapour ◽  
Monsoon Season ◽  
Winter Season ◽  
Precipitable Water ◽  
Satellite System ◽  
Reanalysis Data ◽  
Regional Variability ◽  
Precipitable Water Vapour ◽  
Post Monsoon ◽  
Gnss Data

Abstract. The spatiotemporal variations of integrated precipitable water vapor (IPWV) are very important to understand the regional variability of water vapour. Traditional in-situ measurements of IPWV in Indian region are limited and therefore the performance of satellite and Copernicus Atmosphere Meteorological Service (CAMS) retrievals with Indian Global Navigation Satellite System (GNSS) taking as reference has been analyzed. In this study the CAMS reanalysis retrieval one year (2018), Indian GNSS and INSAT-3DR sounder retrievals data for one & half years (January-2017 to June-2018) has been utilized and computed statistics. It is noticed that seasonal correlation coefficient (CC) values between INSAT-3DR and Indian GNSS data mainly lie within the range of 0.50 to 0.98 for all the selected 19 stations except Thiruvanathpuram (0.1), Kanyakumari (0.31), Karaikal (0.15) during monsoon and Panjim (0.2) during post monsoon season respectively. The seasonal CC values between CAMS and INSAT-3DR IPWV are ranges 0.73 to .99 except Jaipur (0.16) & Bhubneshwar (0.29) during pre-monsoon season, Panjim (0.38) during monsoon, Nagpur (0.50) during post-monsoon and Dibrugarh (0.49) Jaipur (0.58) & Bhubneshwar (0.16) during winter season respectively .The root mean square error (RMSE) values are higher under the wet conditions (Pre Monsoon & Monsoon season) than under dry conditions (Post Monsoon & Winter season) and found differences in magnitude and sign of bias of INSAT-3DR, CAMS with respect to GNSS IPWV from station to station and season to season. This study will help to improve understanding and utilization of CASMS and INSAT-3DR data more effectively along with GNSS data over land, coastal and desert locations in term of seasonal flow of IPWV which is an essential integrated variable in forecasting applications.

scholarly journals Spatial interpolation techniques for a near real-time mapping of pressure and temperature data

2016 ◽  
Author(s):  
Ilaria Ferrando ◽  
Pierluigi De Rosa ◽  
Bianca Federici ◽  
Domenico Sguerso
Keyword(s):  
Real Time ◽  
Physical Model ◽  
Digital Terrain Model ◽  
Precipitable Water ◽  
Satellite System ◽  
Total Delay ◽  
Local Pressure ◽  
Precipitable Water Vapour ◽  
Using Data ◽  
Global Navigation Satellite

Among the different techniques for atmosphere monitoring, the GNSS (Global Navigation Satellite System) can provide an innovative contribution (Bevis et al.,1992; Crespi et al., 2004; Sguerso et al., 2013, 2015). The Laboratory of Geomatics, Geodesy and GIS of the University of Genoa has identified a GIS procedure and a simplified physical model to monitor the Precipitable Water Vapour (PWV) content, using data measured by existing infrastructures. The starting points are local estimations of Zenith Total Delay (ZTD) from a GNSS Permanent Stations (PSs) network, a Digital Terrain Model (DTM) and local Pressure (P) and Temperature (T) measurements (Sguerso et al., 2014; Ferrando et al., 2016). The present paper shows the study of the most appropriate interpolation technique for P and T data to create PWV maps in a quick, stable and automatic way, to support the monitoring of intense meteorological events for both a posteriori and near real-time applications. The resulting P and T maps were compared to meteorological re-analysis, to check the reliability of the simplified physical model. Additionally, the Regression Kriging (RK) was employed to evaluate the data correlation with elevation and to study the applicability of the technique.

Modelling Precipitable Water Vapour (PWV) Over Nigeria from Ground-Based GNSS

2021 ◽  
Vol 8 (1) ◽  
pp. 41-50
Author(s):  
Bawa Swafiyudeen ◽  
Usman Ibrahim Sa'i ◽  
Bala Adamu ◽  
Abubakar Aliyu Zailani ◽  
Adamu Abubakar Musa ◽  
...  
Keyword(s):  
Water Vapour ◽  
Weather Forecasting ◽  
Geographic Location ◽  
Temporal Correlation ◽  
Precipitable Water ◽  
Satellite System ◽  
Spatiotemporal Variability ◽  
Precipitable Water Vapour ◽  
Water Vapour Content ◽  
Environmental Prediction

Global Navigational Satellite System (GNSS) over the past and present time has shown a great potential in the retrieval of the distribution of water vapour in the atmosphere.  Taking the advantage of the effect of the atmosphere on GNSS signal as they travel from the constellation of satellite to ground-based GNSS receivers such that information (water vapour content) about the atmosphere (mostly from the troposphere) can be derived is referred to as GNSS meteorology. This paper presents the spatiotemporal variability of Precipitable Water Vapour (PWV) retrieved from ground–based Global Navigation Satellite System (GNSS) stations over Nigeria for the years 2012 to 2013. In this paper, the GNSS data were processed using GAMIT (ver. 10.70). The GNSS PWV were grouped into daily and monthly averages; the variability of the daily and monthly GNSS PWV were compared and validated with the daily and monthly PWV from National Centre for Environmental Prediction (NCEP) and monthly Rainfall data for the study years respectively. The results revealed that the spatiotemporal variability of PWV across Nigeria is a function of geographic location and seasons. The result shows that there is temporal correlation between GNSS PWV, NCEP PWV and rainfall events. The research also affirms that GNSS PWV could be used to improve weather forecasting/monitoring as well as climate monitoring.

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