A5052809239- Ionosphere and magnetosphere dynamics
- Atmospheric Ozone and Climate
- GNSS positioning and interference
- Geophysics and Gravity Measurements
- Meteorological Phenomena and Simulations
- Climate variability and models
- Atmospheric aerosols and clouds
- Atmospheric chemistry and aerosols
- Earthquake Detection and Analysis
- Air Traffic Management and Optimization
- Atmospheric and Environmental Gas Dynamics
- Geomagnetism and Paleomagnetism Studies
- Renewable Energy and Sustainability
- Spacecraft Design and Technology
- Solar and Space Plasma Dynamics
- Distributed and Parallel Computing Systems
- Air Quality and Health Impacts
- Air Quality Monitoring and Forecasting
- Advanced Computational Techniques and Applications
- Space Exploration and Technology
- Remote-Sensing Image Classification
- Seismology and Earthquake Studies
- Odor and Emission Control Technologies
- Aerospace and Aviation Technology
- Corporate Social Responsibility and Sustainability
GeoSphere Austria
2024
Central Institution for Meteorology and Geodynamics
2017-2022
University of Graz
2011-2020
University of Texas Institute for Geophysics
2011-2014
University Corporation for Atmospheric Research
2011-2013
NSF National Center for Atmospheric Research
2011
Abstract Global Navigation Satellite System (GNSS)‐based radio occultation (RO) is a satellite remote sensing technique providing accurate profiles of the Earth's atmosphere for weather and climate applications. Above about 30 km altitude, however, statistical optimization critical process initializing RO bending angles in order to optimize monitoring utility retrieved atmospheric profiles. Here we introduce an advanced dynamic algorithm, which uses from multiple days European Centre...
Observation of the atmospheric climate and detection changes require high quality data. Radio Occultation (RO) using Global Positioning System (GPS) signals is based on time measurements with precise atomic clocks. It provides a long‐term stable consistent data record global coverage favorable error characteristics. Highest vertical resolution given in upper troposphere lower stratosphere (UTLS). RO exist from GPS/Met mission within 1995–1997, continuous observations are available since...
To examine the claim that Global Positioning System (GPS) radio occultation (RO) data are useful as a benchmark set for climate monitoring, structural uncertainties of retrieved profiles result from different processing methods quantified. Profile‐to‐profile comparisons CHAMP (CHAllenging Minisatellite Payload) January 2002 to August 2008 by six RO centers presented. Differences and standard deviations individual relative inter‐center mean used quantify uncertainty. Uncertainties accumulate...
Abstract. Global Positioning System (GPS) radio occultation (RO) has provided continuous observations of the Earth's atmosphere since 2001 with global coverage, all-weather capability, and high accuracy vertical resolution in upper troposphere lower stratosphere (UTLS). Precise time measurements enable long-term stability but careful processing is needed. Here we provide climate-oriented atmospheric scientists multicenter-based results on RO climatological fields for trend studies. We...
Abstract. Data consistency is an important prerequisite to build radio occultation (RO) climatologies based on a combined record of data from different satellites. The presence multiple RO receiving satellites in orbit over the same time period allows for testing this consistency. We used CHAMP (CHAllenging Minisatellite Payload geoscientific research), six FORMOSAT-3/COSMIC (Formosa Satellite Mission 3/Constellation Observing System Meteorology, Ionosphere and Climate, F3C), GRACE-A...
Abstract. The utilization of radio occultation (RO) data in atmospheric studies requires precise knowledge error characteristics. We present results an empirical analysis GPS RO bending angle, refractivity, dry pressure, geopotential height, and temperature. find very good agreement between characteristics different missions (CHAMP, GRACE-A, Formosat-3/COSMIC (F3C)). In the global mean, observational errors (standard deviation from "true" profiles at mean tangent point location) agree within...
Abstract. Due to the measurement principle of radio occultation (RO) technique, RO data are highly suitable for climate studies. profiles can be used build climatological fields different atmospheric parameters like bending angle, refractivity, density, pressure, geopotential height, and temperature. climatologies affected by random (statistical) errors, sampling systematic yielding a total error. Based on empirical error estimates, we provide simple analytical model these components, which...
The vertical and spatial structure of the atmospheric El Niño‐Southern Oscillation (ENSO) signal is investigated using radio occultation (RO) data from August 2006 to December 2010. Due their high resolution global coverage, RO are well suited describe full 3‐dimensional ENSO in troposphere lower stratosphere. We find that interannual temperature anomalies equatorial region show a natural decomposition into zonal‐mean eddy (deviations zonal‐mean) components both related ENSO. Consistent with...
Abstract High‐resolution measurements from Global Navigation Satellite System (GNSS) radio occultation (RO) provide atmospheric profiles with independent information on altitude and pressure. This unique property is of crucial advantage when analyzing characteristics that require joint knowledge pressure or other thermodynamic variables. Here we introduce demonstrate the utility this RO discuss computation, uncertainty, use isohypsic coordinates—mean sea level geopotential height—as well as...
Abstract. Characteristics of the lapse rate tropopause are analyzed globally for altitude and temperature using global positioning system (GPS) radio occultation (RO) data from late 2001 to end 2013. RO profiles feature high vertical resolution excellent quality in upper troposphere lower stratosphere, which key factors determination, including multiple ones. provide measurements allow examination both temporal spatial characteristics based entirely on observational measurements. To...
Abstract. The demand for high-quality atmospheric data records, which are applicable in climate studies, is undisputed. Using such records requires knowledge of the quality and specific characteristics all contained sources. latest version Wegener Center (WEGC) multi-satellite Global Positioning System (GPS) radio occultation (RO) record, OPSv5.6, provides globally distributed upper-air satellite high quality, usable other high-accuracy applications. GPS RO technique has been deployed...
Abstract Global positioning system (GPS) radio occultation (RO) observations, first made of Earth’s atmosphere in 1995, have contributed new ways to the understanding thermal structure and variability tropical upper troposphere–lower stratosphere (UTLS), an important component climate system. The UTLS plays essential role global radiative balance, exchange water vapor, ozone, other chemical constituents between troposphere stratosphere, transfer energy from stratosphere. With their high...
Abstract. Radio occultation (RO) sensing is used to probe the earth's atmosphere in order obtain information about its physical properties. With a main interest parameters of neutral atmosphere, there need perform correction ionospheric contribution bending angle. Since this an approximation first order, exists residual, which can be expected larger when ionization high (day versus night, low solar activity). The residual systematically affects accuracy atmospheric at altitudes, altitudes...
Abstract. Volcanic eruptions comprise an important airborne hazard for aviation. Although significant events are rare, e.g. compared to the threat of thunderstorms, they have a very high impact. The current state tools and abilities mitigate aviation hazards associated with assumed volcanic cloud was tested within international demonstration exercise. Experts in field assembled at Schwarzenberg barracks Salzburg, Austria, order simulate sequence procedures case scenario artificial eruption...
Abstract. High-quality volcanic ash forecasts are crucial to minimize the economic impact of hazards on air traffic. Decision-making is usually based numerical dispersion modelling with only one model realization. Given inherent uncertainty such an approach, a multi-model multi-source term ensemble has been designed and evaluated for Eyjafjallajökull eruption in May 2010. Its use flight planning discussed. Two ensembles were built: first output four models their own implementation ejection....
Global Positioning System (GPS) radio occultation (RO) measurements are proven highly useful for observing the thermal structure of troposphere and stratosphere. Here we use RO data first time to derive climatological wind fields from sampling error-corrected geopotential height on isobaric surfaces about 800 hPa 3 hPa. We find monthly mean geostrophic gradient (2007 2012, 500 km horizontal resolution, outside tropics) clearly capture all main features, with differences atmospheric analysis...
Explosive volcanic eruptions can inject large amounts of ash and gases into the atmosphere. Such aerosols have a significant impact on surrounding environment, there is need to closely investigate their effects meteorology local, regional, even continental scale. This work presents study 2010 Eyjafjallajökull eruption resulting dispersion its radiative feedback meteorological conditions with Weather Research Forecasting model on-line Chemistry (WRF-Chem). Two runs, one meteorology-only...
Abstract. Atmospheric blocking has been closely investigated in recent years due to its impact on weather and climate, such as heat waves, droughts, flooding. We use, for the first time, satellite-based observations from Global Positioning System (GPS) radio occultation (RO) explore their ability resolve order potentially open up new avenues complementing models reanalyses. RO delivers globally available vertically highly resolved profiles of atmospheric variables temperature geopotential...
The Global Navigation Satellite System (GNSS) Radio Occultation (RO) is a key technique for obtaining thermodynamic profiles of temperature, humidity, pressure, and density in the Earth’s troposphere. However, due to refraction effects both dry air water vapor at low altitudes, retrieval accurate challenging. Here we introduce new moist algorithm aiming improve quality RO-retrieved including uncertainty estimation clear sequence steps. first uses RO temperature pressure background...
Abstract. Tropical temperature variability over 10–30 km and associated Kelvin-wave activity are investigated using GPS radio occultation (RO) data from January 2002 to December 2014. RO a powerful tool for quantifying tropical oscillations with short vertical wavelengths due their high resolution accuracy precision. Gridded temperatures show the strongest in tropopause region (on average 3 K2). Large-scale zonal is dominated by transient sub-seasonal waves (2 K2), about half of variance...
Abstract. We introduce a new dynamic statistical optimization algorithm to initialize ionosphere-corrected bending angles of Global Navigation Satellite System (GNSS)-based radio occultation (RO) measurements. The estimates background and observation error covariance matrices with geographically varying uncertainty profiles realistic global-mean correlation matrices. estimated by the approach are more accurate than in simplified existing approaches can therefore be used provide optimal angle...
Abstract. In this paper, we introduce a bending angle radio occultation climatology (BAROCLIM) based on Formosat-3/COSMIC (F3C) data. This represents the monthly-mean atmospheric state from 2006 to 2012. Bending angles (RO) measurements are obtained accumulation of change in raypath direction Global Positioning System (GPS) signals. Best quality these near-vertical profiles is found middle troposphere up mesosphere. Beside RO also use data Mass Spectrometer and Incoherent Scatter Radar...
Abstract. Radio occultation (RO) data are increasingly used in climate research. Accurate phase (change) measurements of Global Positioning System (GPS) signals the basis for retrieval near-vertical profiles bending angle, microwave refractivity, density, pressure, and temperature. If temperature is calculated from observed refractivity with assumption that water vapor zero, product called "dry temperature", which commonly to study earth's atmosphere, e.g., when analyzing trends due global...
Abstract. We provide atmospheric temperature variability indices for the tropical troposphere and stratosphere based on global navigation satellite system (GNSS) radio occultation (RO) measurements. By exploiting high vertical resolution uniform distribution of GNSS RO soundings we introduce two approaches, both an empirical orthogonal function (EOF) analysis. The first method utilizes whole horizontal field from 30∘ S to N 2 35 km altitude. resulting indices, leading principal components,...