Impact of single-point GPS integrated water vapor estimates on short-range WRF model forecasts over southern India

Kumar, Prashant; Gopalan, Kaushik; Shukla, Bipasha Paul; Shyam, Abhineet

doi:10.1007/s00704-016-1894-7

Cited by 5 publications

(5 citation statements)

References 23 publications

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“…This finding of a small but significant positive impact on short-range forecasts is consistent with other studies reported in the literature. While Giannaros et al [25] and Rohm et al [26] show large improvements in precipitation forecasts over Greece and Central Europe respectively, Kumar et al [16] and Risanto et al [27] show modest positive impact of assimilating GPS-derived IWV. This study provides further evidence that GPS-derived weather observations have significant potential for positively impacting weather studies and forecasts in the Indian region.…”

Section: Discussionmentioning

confidence: 99%

“…The most significant finding is that the forecast skill is improved with assimilation of GPS-IWV data each year as the number of stations has increased; this suggests that the increase in the network density can lead to further forecast improvement. In the Indian context, Kumar et al [16] found a small positive impact on 24-h forecasts upon assimilating observations from a single GPS station in Bangalore. In contrast, the current study analyzes the impact of IWV derived from a network of GPS stations.…”

Section: Introductionmentioning

confidence: 99%

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An Observational Study of GPS-Derived Integrated Water Vapor over India

et al. 2021

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This study describes the process of deriving integrated water vapor (IWV) from (a) a set of 18 GPS receivers that were installed at different airports across India and (b) a pair of GPS receivers located in Ahmedabad situated around 8 km apart. The Zenith Tropospheric Delay was estimated from the GPS observations using the GAMIT software. Further, IWV was estimated from the ZTD values using surface temperature and pressure from ERA-I reanalysis as additional inputs. The IWV estimates for 1 year—March 2013 to February 2014—were compared with ECMWF Reanalysis Interim (ERA-I) reanalysis as well as radiosonde soundings. The Root Mean Squared Error (RMSE) was ≈6 mm or better for most stations. The IWV estimates for July 2013 were assimilated into the WRF model and had a positive impact on model analysis of IWV. The forecasted rain improved by up to 3–4 mm/day in some regions as a result of GPS-derived IWV estimates. For the Ahmedabad receivers, the GPS-derived IWV was compared with IWV from ERA-I reanalysis and was found to have a RMSE of ≈7.7 mm which is <20% of the mean value. The study demonstrates that the observed IWV variation is consistent with rainfall patterns over Ahmedabad. The rise and dips in the IWV correlate well with the active-break cycle in the monsoon rain. The study demonstrates the value of local measurements of IWV with high temporal frequency, as they are more likely to respond to fast-moving weather phenomena such as rainfall. Thus, the GPS-derived IWV measurements are likely to have significant value in the short-term forecasts of precipitation.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An Observational Study of GPS-Derived Integrated Water Vapor over India

et al. 2021

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“…A further step should deal with the use of IWV GNSS and ZTD GNSS as input for weather prediction, particularly for the forecast of heavy precipitation events. The assimilation of ZTD on numerical weather prediction models has been performed in several regions of the world (Stoycheva et al, 2017;Ahmed et al, 2015;Kumar et al, 2017;Rohm et al, 2019;Singh et al, 2019), with improvements in the forecast of key variables as surface pressure, moisture transport or precipitation. In this sense, considering that the IWV alone is not enough to describe precipitation variations over the region, the evolution of atmospheric pressure and wind patterns should be analyzed for a larger number of case studies, comparing forecasts and observations.…”

Section: Discussionmentioning

confidence: 99%

Estimation of integrated water vapor derived from Global Navigation Satellite System observations over Central-Western Argentina (2015–2018). Validation and usefulness for the understanding of regional precipitation events

Camisay

Rivera

Mateo

et al. 2020

Journal of Atmospheric and Solar-Terrestrial Physics

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“…In addition to this, it must be noted that regions lacking dense networks of groundbased GNSS stations can also benefit from GNSS data assimilation. Kumar et al [129] showed that assimilating GNSS data from a single station was enough to locally improve (∼10%) the short-term forecasts in an experiment over southern India during the monsoon. Of course, it will be better if there is moisture information from more GNSS stations, but regions lacking moisture information from other sources can benefit from GNSS data even with a single station in the region of interest.…”

Section: Assimilationmentioning

confidence: 99%

Review on the Role of GNSS Meteorology in Monitoring Water Vapor for Atmospheric Physics

Vaquero-Martínez

Antón

2021

Remote Sensing

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After 30 years since the beginning of the Global Positioning System (GPS), or, more generally, Global Navigation Satellite System (GNSS) meteorology, this technique has proven to be a reliable method for retrieving atmospheric water vapor; it is low-cost, weather independent, with high temporal resolution and is highly accurate and precise. GNSS ground-based networks are becoming denser, and the first stations installed have now quite long time-series that allow the study of the temporal features of water vapor and its relevant role inside the climate system. In this review, the different GNSS methodologies to retrieve atmospheric water vapor content re-examined, such as tomography, conversion of GNSS tropospheric delay to water vapor estimates, analyses of errors, and combinations of GNSS with other sources to enhance water vapor information. Moreover, the use of these data in different kinds of studies is discussed. For instance, the GNSS technique is commonly used as a reference tool for validating other water vapor products (e.g., radiosounding, radiometers onboard satellite platforms or ground-based instruments). Additionally, GNSS retrievals are largely used in order to determine the high spatio-temporal variability and long-term trends of atmospheric water vapor or in models with the goal of determining its notable influence on the climate system (e.g., assimilation in numerical prediction, as input to radiative transfer models, study of circulation patterns, etc.).

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Impact of single-point GPS integrated water vapor estimates on short-range WRF model forecasts over southern India

Cited by 5 publications

References 23 publications

An Observational Study of GPS-Derived Integrated Water Vapor over India

An Observational Study of GPS-Derived Integrated Water Vapor over India

Estimation of integrated water vapor derived from Global Navigation Satellite System observations over Central-Western Argentina (2015–2018). Validation and usefulness for the understanding of regional precipitation events

Review on the Role of GNSS Meteorology in Monitoring Water Vapor for Atmospheric Physics

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