GPS water vapor and its comparison with radiosonde and ERA-Interim data in Algeria

Namaoui, Houaria; Kahlouche, Salem; Belbachir, Ahmed Hafid; Malderen, Roeland Van; Brenot, Hugues; Pottiaux, Eric

doi:10.1007/s00376-016-6111-1

Cited by 21 publications

(9 citation statements)

References 21 publications

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“…Secondly, despite these differences in the thermal structure of the tropical atmosphere of Costa Rica, the T m calculations using the Bevis equation showed small differences with respect to the corresponding calculations based on radiosonde data. This finding also agrees with the calculations made in Algeria and Argentina where Namaoui et al and Fernández et al estimated the uncertainty of the T m values and found that variations up to 15K produced small differences in the final estimation of GPS PWV, which did not exceed 2 mm [27,40]. Thirdly, the poor correlation observed between T s and T m at MROC deserves further discussion.…”

Section: Discussionsupporting

confidence: 90%

“…400 km), the good correlation between the GPS PWV estimates at AACR and LIBE was an expected result of our analysis, as both sites are located on the Pacific slope and share similar climatological features (e.g., analogous precipitation patterns, Figure 4A). Moreover, we also confirm the good agreement between the GPS PWV calculations and the radiosonde-based measurements reported by others [6,9,26,27,41]. For example, Spearman's correlation coefficients for the GPS PWV and the radiosonde-based calculations were 0.913 (p < 0.001) and 0.902 (p < 0.001) during the dry and wet season, respectively.…”

Section: Discussionsupporting

confidence: 90%

“…Overall, the ZHD is due to the effect of dry air, contributing to at least 90% of the total tropospheric delay, whereas the ZWD represents less than 10% of the signal. Therefore, the ZTD depends on the air mass between the receiver and satellite and can be expressed as a function of ground atmospheric pressure [26][27][28]:…”

Section: Of 18mentioning

confidence: 99%

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GPS Precipitable Water Vapor Estimations over Costa Rica: A Comparison against Atmospheric Sounding and Moderate Resolution Imaging Spectrometer (MODIS)

Campos-Arias

Esquivel‐Hernández

Valverde-Calderón

et al. 2019

Climate

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The quantification of water vapor in tropical regions like Central America is necessary to estimate the influence of climate change on its distribution and the formation of precipitation. This work reports daily estimations of precipitable water vapor (PWV) using Global Positioning System (GPS) delay data over the Pacific region of Costa Rica during 2017. The GPS PWV measurements were compared against atmospheric sounding and Moderate Resolution Imaging Spectrometer (MODIS) data. When GPS PWV was calculated, relatively small biases between the mean atmospheric temperatures (T m ) from atmospheric sounding and the Bevis equation were found. The seasonal PWV fluctuations were controlled by two of the main circulation processes in Central America: the northeast trade winds and the latitudinal migration of the Intertropical Convergence Zone (ITCZ). No significant statistical differences were found for MODIS Terra during the dry season with respect GPS-based calculations (p > 0.05). A multiple linear regression model constructed based on surface meteorological variables can predict the GPS-based measurements with an average relative bias of −0.02 ± 0.19 mm/day (R 2 = 0.597). These first results are promising for incorporating GPS-based meteorological applications in Central America where the prevailing climatic conditions offer a unique scenario to study the influence of maritime moisture inputs on the seasonal water vapor distribution.Climate 2019, 7, 63 2 of 18 of atmospheric water vapor content are needed to improve the predictability of rainfall and the understanding of and feedback in climate related processes [5,6].A quantifiable parameter useful for studying water vapor is the precipitable (or integrated) water vapor (PWV). Precipitable water vapor mainly comprises tropospheric water vapor and the less abundant stratospheric water and can be used to analyze water vapor variability and its contributions to climate change [6]. The classical approach to gather information about PWV is using atmospheric sounding based on radiosonde profiles [7]. However, due to high costs, radiosonde networks lack spatial and temporal resolutions and, thus, provide limited information to carry out detailed studies of weather and climate. For example, radiosondes are usually launched 1-2 times per day in monitoring stations spaced several hundred kilometers from each other. In recent years, the fast development of ground-based GPS networks allows a new source of water vapor information. As atmospheric water changes the atmospheric refractivity, satellite-receiver path delays provide a unique information on the total water vapor within the troposphere and stratosphere. Therefore, GPS has become a standard technique for measuring PWV with some noticeable advantages over radiosondes. For instance, GPS can be used in all weather conditions and has low operation costs, allowing for a high temporal resolution with numerous records throughout the daytime and nighttime [8][9][10]. In Costa Rica, there are 14 Global Navigation Satellite Syst...

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Section: Discussionsupporting

confidence: 90%

Section: Discussionsupporting

confidence: 90%

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GPS Precipitable Water Vapor Estimations over Costa Rica: A Comparison against Atmospheric Sounding and Moderate Resolution Imaging Spectrometer (MODIS)

Campos-Arias

Esquivel‐Hernández

Valverde-Calderón

et al. 2019

Climate

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“…ECMWF and National Centers for Environmental Prediction (NCEP) have developed some numerical weather prediction models based on historical multiple data sources and provided a global reanalysis dataset, such as the most used ERA-Interim. ERA5 is a new-generation ECMWFretrieved reanalysis product; it has higher temporal and spatial resolutions [27]. ECMWF analysis represents optimal humidity estimates from high-quality observations among multisatellite sounders, imagers, and conventional in situ observations through a data assimilation system [28][29][30]; researchers have validated global ERA-Interim integrated precipitable water using ground-based GNSS observations and related techniques, which showed a high correlation [8].…”

Section: Introductionmentioning

confidence: 99%

Precipitable Water Vapor Retrieval and Analysis by Multiple Data Sources: Ground-Based GNSS, Radio Occultation, Radiosonde, Microwave Satellite, and NWP Reanalysis Data

Zhang

et al. 2018

Journal of Sensors

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Precipitable water vapor (PWV) content detection is vital to heavy rain prediction; up to now, lots of different measuring methods and devices are developed to observe PWV. In general, these methods can be divided into two categories, ground-based or space-based. In this study, we analyze the advantages and disadvantages of these technologies, compare retrieved atmosphere parameters by different RO (radio occultation) observations, like FORMOSAT-3/COSMIC (Formosa Satellite-3 and Constellation Observing System for Meteorology, Ionosphere, and Climate) and FY3C (China Feng Yun 3C), and assess retrieved PWV precision with a radiosonde. Besides, we interpolate PWV from NWP (numerical weather prediction) reanalysis data for more comparison and analysis with RO. Specifically, ground-based GNSS is of high precision and continuous availability to monitor PWV distribution; in our paper, we show cases to validate and compare GNSS retrieving PWV with a radiosonde. Except GNSS PWV, we give two different radio occultation sounding results, COSMIC and FY3C, to validate the precision to monitor PWV from space in a global area. FY3C results containing Beidou (China Beidou Global Satellite Navigation System) radio occultation events need to be emphasized. So, in our study, we get the retrieved atmospheric profiles from GPS and Beidou radio occultation observations and derive atmosphere PWV by a variational retrieval method based on these data over a global area. Besides, other space-based methods, such as microwave satellite, are also useful in detecting PWV distribution situations in a global area from space; in this study, we present a case of retrieved PWV using microwave satellite observation. NWP reanalysis data ECMWF (European Centre for Medium-Range Weather Forecasts) ERA-Interim and the new-generation reanalysis data ERA5 provide global grid atmosphere parameters, like surface temperature, different-level pressures, and precipitable water. We show cases of retrieved PWV and validate the precision with radiosonde results and compare new reanalysis dataset ERA5 with ERA-Interim, finding that ERA5 can get higher precision-retrieved atmosphere parameters and PWV. In the end, from our comparison, we find that the retrieved PWV from RO (FY3C and COSMIC) and ECMWF reanalysis data (ERA-Interim and ERA5) have a high positive correlation and that almost all R2 values exceed 0.9, compare retrieved PWV with a radiosonde, and find that whether it is RO and ECMWF reanalysis data, ground-based GNSS, or microwave satellite, they all show small biases.

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“…Določitev vpliva troposfere na opazovanja GNSS iz radiosondažnih meritev niso novost. V zadnjem času so raziskave potekale na Kitajskem (Liang et al, 2015), v Egiptu (Abdelfatah, Mousa in El-Fiky, 2015), Alžiriji (Namaoui et al, 2017) in bližini Lizbone na Portugalskem (Benevides et al, 2017) kot tudi na območju Tihega oceana v bližini Japonske (Shoji et al, 2017). Na območju Slovenije je obsežna študija celotnega vpliva atmosfere (troposfere in ionosfere), vendar le za opazovanja GPS (angl.…”

Section: Uvodunclassified

Determination of tropospheric GNSS impacts from a radiosonde data series in Ljubljana: case study from october to december 2017

Senica¹,

Sterle²,

Prešeren³

2018

geod. vestn.

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GPS water vapor and its comparison with radiosonde and ERA-Interim data in Algeria

Cited by 21 publications

References 21 publications

GPS Precipitable Water Vapor Estimations over Costa Rica: A Comparison against Atmospheric Sounding and Moderate Resolution Imaging Spectrometer (MODIS)

GPS Precipitable Water Vapor Estimations over Costa Rica: A Comparison against Atmospheric Sounding and Moderate Resolution Imaging Spectrometer (MODIS)

Precipitable Water Vapor Retrieval and Analysis by Multiple Data Sources: Ground-Based GNSS, Radio Occultation, Radiosonde, Microwave Satellite, and NWP Reanalysis Data

Determination of tropospheric GNSS impacts from a radiosonde data series in Ljubljana: case study from october to december 2017

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