Abstract. Global Navigation Satellite Systems (GNSS) meteorology is an established operational service providing hourly updated GNSS tropospheric products to the National Meteorologic Services (NMS) in Europe. In the last decade through the ground-based GNSS network densification and new processing strategies like Precise Point Positioning (PPP) it has become possible to obtain sub-hourly tropospheric products for monitoring severe weather events. In this work one year (JanuaryDecember 2013) of sub-hourly GNSS tropospheric products (Zenith Total Delay) are computed using the PPP strategy for 5 seven stations in Bulgaria. In order to take advantage of the sub-hourly GNSS data to derive Integrated Water Vapour (IWV) surface pressure and temperature with similar temporal resolution is required. As the surface observations are on 3 hourly basis the first step is to compare the surface pressure and temperature from numerical weather prediction model Weather Forecasting and Research (WRF) with observations at three synoptic stations in Bulgaria. The mean difference between the two data-sets for 1) surface pressure is less than 0.5 hPa and the correlation is over 0.989, 2) temperature the largest mean difference is Between 00 and 01 UTC the GNSS IWV tends to be underestimate IWV which is likely due to the processing window used.
Abstract. Atmospheric sounding using the Global Navigation Satellite Systems (GNSS) is a well established research field in Europe. At present, GNSS data from 1800 stations are available for model validation and assimilation in state-of-the-art models used for operational numerical weather prediction Centers in Europe. Advances in GNSS data processing is making possible to also use the GNSS data for climatic trend analysis, an emerging new application. In Bulgaria and Southeast Europe the use of GNSS for atmospheric sounding is currently under development. As a first step the Sofia University Atmospheric Data Archive (SUADA) is developed. SUADA is user friendly database and includes GNSS tropospheric products like Zenith Total Delay (ZTD) and derivatives like vertically Integrated Water Vapour (IWV) as well as observations from Radiosonde and surface atmospheric data. Archived in SUADA are: (1) GNSS tropospheric products (over 12 000 000 individual observations) and derivatives (over 55 000) from five GNSS processing strategies and 37 stations for the period 1997–2013 with temporal resolution from 5 min to 6 h and (2) Radiosonde IWV data (over 6000 observations) for station Sofia (1999–2012). Presented are two applications of the SUADA data for study of long and short term variation of IWV over Bulgaria during the 2007 heat wave and intense precipitation events in 2012.
Abstract.Ground-based GNSS (Global Navigation Satellite Systems) have efficiently been used since the 1990s as a meteorological observing system. Recently scientists used GNSS time series of precipitable water vapor (PWV) for climate research. In this work, we use time series from GNSS, European Center for Medium-Range Weather Forecasts Reanalysis (ERA-Interim) data, and meteorological measurements to evaluate climate evolution in Central Europe. The assessment of climate change
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