Anna Klos

Anna Klos
Military University of Technology | WAT · Faculty of Civil Engineering and Geodesy

Ph.D.-habil.

About

109
Publications
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835
Citations

Publications

Publications (109)
Article
Full-text available
Each of the GPS-derived time series consists of the deterministic (functional) and stochastic part. We propose that the deterministic part includes all periodicities from 1st to 9th harmonics of residual Chandler, tropical and draconitic periods and compare it with commonly used calculations of the annual and semi-annual tropical curve. Then, we ad...
Article
Full-text available
The velocity estimates and their uncertainties derived from position time series of Global Navigation Satellite System (GNSS) stations are affected by seasonal signals and their harmonics, and the statistical properties, i.e. the stochastic noise, contained in the series. If the deterministic model in the form of linear trend and periodic terms is...
Article
Full-text available
The coordinate time series determined with the Global Positioning System (GPS) contain annual and semi-annual periods that are routinely modeled by two periodic signals with constant amplitude and phase-lag. However, the amplitude and phase-lag of the seasonal signals vary slightly over time. Various methods have been proposed to model these variat...
Article
The Global Positioning System (GPS) is routinely used to measure the elastic response of Earth to continental hydrological mass changes, occurring at various temporal and spatial scales. While long-term and seasonal height changes are well observed in GPS height time series, the subseasonal deformations are less well resolved. A suite of prediction...
Article
Full-text available
We reassess the absolute and relative sea level changes at 38 tide gauge stations in the earthquake-affected Western North Pacific for the 1993-2015 period, focusing on the vertical land motion (VLM) which is crucial for narrowing the gap between these estimates. In this area, simply discarding all earthquake-affected sites, one overestimates the a...
Presentation
Full-text available
Nowadays, huge number of regions spread around the World are struggling with the problem of water availability. Hence, the quality and quantity of continental water resources must be regularly controlled. Currently, land water components are monitored, among others by measuring their weight, type and density or analyzing the level of water in the s...
Article
Full-text available
In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and mo...
Article
Full-text available
In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and mo...
Article
Full-text available
We examine the sensitivity of the Global Positioning System (GPS) to non-tidal loading for a set of continental Eurasia permanent stations. We utilized daily vertical displacements available from the Nevada Geodetic Laboratory (NGL) at stations located at least 100 km away from the coast. Loading-induced predictions of displacements of earth’s crus...
Article
Full-text available
A correction to this paper has been published: https://doi.org/10.1007/s10291-021-01141-y
Article
Although the statistical significances for the trends of integrated water vapor (IWV) are essential for a correct interpretation of climate change signals, obtaining accurate IWV trend estimates with realistic uncertainties remains a challenge. This study evaluates the feasibility of the IWV trends derived from the newly released fifth generation E...
Article
Full-text available
We have reconstructed integrated water vapor (IWV) using the zenith wet delays to track the properties of hurricanes and explore their spatial and temporal distributions estimated from 922 GPS stations. Our results show that a surge in GPS-derived IWV occurred at least six hours prior to the landfall of two major hurricanes (Harvey and Irma) that s...
Article
Full-text available
The Gravity Recovery and Climate Experiment (GRACE) mission has enabled mass changes and transports in the hydrosphere, cryosphere and oceans to be quantified with unprecedented resolution. However, while this legacy is currently being continued with the GRACE Follow-On (GRACE-FO) mission there is a gap of 11 months between the end of GRACE and the...
Article
A significant part of the World population lives in the coastal zone, which is affected by sea level rise and extreme events. Consistent and precise new measurements are needed to assess and predict these changes. New altimeter missions equipped with Synthetic Aperture Radar (SAR) mode provide more accurate sea level heights. In this work we analys...
Article
Full-text available
Earth’s crust deforms in various time and spatial resolutions. To estimate them, geodetic observations are widely employed and compared to geophysical models. In this research, we focus on the Earth’s crust deformations resulting from hydrology mass changes, as observed by GRACE (Gravity Recovery and Climate Experiment) gravity mission and modeled...
Chapter
Full-text available
Vertical displacements and time-varying gravity fluctuations are representative of various deformation mechanisms of the Earth occurring at different spatial and temporal scales. The inter-comparison of ground-gravity measurements with vertical surface displacements enables to estimate the transfer function of the Earth at various time-scales relat...
Chapter
Full-text available
Tropical cyclones are one of the most powerful severe weather events that produce devastating socioeconomic and environmental impacts in the areas they strike. Therefore, monitoring and tracking of the arrival times and path of the tropical cyclones are extremely valuable in providing early warning to the public and governments. Hurricane Florence...
Article
Full-text available
Gravity Recovery and Climate Experiment (GRACE) mission data is widely used in various fields of science. GRACE explored changes of the gravity field regularly from April 2002 to June 2017. In the following research, we examine variance of signal contained in two different formats of GRACE data: standard spherical harmonics and mass concentration b...
Presentation
Full-text available
Presently, Gravity Recovery and Climate Experiment (GRACE) mission data is widely used in various fields of science. The longest satellite gravimetric mission regularly explored changes of the gravity field from April 2002 to October 2017. Nowadays, its follow-on mission (GRACE-FO) observes gravity changes from May 2018, providing new greater resea...
Article
Full-text available
We assess the performance of different break detection methods on three sets of benchmark datasets, each consisting of 120 daily time series of integrated water vapor differences. These differences are generated from the Global Positioning System (GPS) measurements at 120 sites worldwide, and the numerical weather prediction reanalysis (ERA‐Interim...
Chapter
Seasonal signatures observed within the Global Navigation Satellite System (GNSS) position time series are routinely modelled as annual and semi-annual periods with constant amplitudes over time. However, in this chapter, we demonstrate that these amplitudes can vary significantly over time, by as much as 3 mm at some stations. Different methods ha...
Article
Full-text available
This review paper presents research results on geodetic positioning and applications carried out in Poland, and related to the activities of the International Association of Geodesy (IAG) Commission 4 "Positioning and Applications" and its working groups. It also constitutes the chapter 4 of the national report of Poland for the International Union...
Article
Full-text available
We describe a comprehensive analysis of the 469 European Global Positioning System (GPS) vertical position time series. The assumptions we present should be employed to perform the post-glacial rebound (PGR)-oriented comparison. We prove that the proper treatment of either deterministic or stochastic components of the time series is indispensable t...
Chapter
For the first time, we introduced the probabilistic principal component analysis (pPCA) regarding the spatio-temporal filtering of Global Navigation Satellite System (GNSS) position time series to estimate and remove Common Mode Error (CME) without the interpolation of missing values. We used data from the International GNSS Service (IGS) stations...
Chapter
Full-text available
We described a spatio-temporal analysis of environmental loading models: atmospheric, continental hydrology, and non-tidal ocean changes, based on multichannel singular spectrum analysis (MSSA). We extracted the common annual signal for 16 different sections related to climate zones: equatorial, arid, warm, snow, polar and continents. We used the l...
Chapter
A reliable subtraction of seasonal signals from the Global Positioning System (GPS) position time series is beneficial for the accuracy of derived velocities. In this research, we propose a two-stage solution of the problem of a proper determination of seasonal changes. We employ environmental loading models (atmospheric, hydrological and ocean non...
Presentation
Full-text available
W ramach opracowania obserwacji GPS (ang. Global Positioning System) otrzymujemy wartości zenitalnego opóźnienia troposferycznego (ZTD, ang. Zenith Tropospheric Delay), które świadczą o opóźnieniu sygnału w troposferze na drodze satelita-odbiornik. Trendy wyznaczone z szeregów czasowych ZTD o długości nawet 25 lat są obecnie asymilowane do numerycz...
Article
Full-text available
Various methods have been used to model the time-varying curves within the global positioning system (GPS) position time series. However, very few consider the level of noise a priori before the seasonal curves are estimated. This study is the first to consider the Wiener filter (WF), already used in geodesy to denoise gravity records, to model the...
Presentation
Full-text available
Detecting breaks in tropospheric data is indispensable, since these breaks directly affect the trend estimates from Zenith Total Delay (ZTD) series or Integrated Water Vapor (IWV) records. Various algorithms have been already employed to report the exact epochs of break points during the entire time span of ZTD or IWV series. This procedure is know...
Article
Full-text available
A reliable subtraction of seasonal signals from the Global Positioning System (GPS) position time series is beneficial for the accuracy of derived velocities. In this research, we propose a two-stage solution of the problem of a proper determination of seasonal changes. We employ environmental loading models (atmospheric, hydrological and ocean non...
Article
Full-text available
We described a spatio-temporal analysis of environmental loading models: atmospheric, continental hydrology, and non-tidal ocean changes, based on Multichannel Singular Spectrum Analysis (MSSA). We extracted the common annual signal for 16 different sections related to climate zones: equatorial, arid, warm, snow, polar and continents. We used the l...
Article
Full-text available
For the first time we introduced the probabilistic Principal Component Analysis (pPCA) regarding the spatio-temporal filtering of Global Navigation Satellite System (GNSS) position time series in order to estimate and remove Common Mode Error (CME) without interpolation of missing values. We used data from the International GNSS Service (IGS) stati...
Poster
Full-text available
The process of homogenization employed for tropospheric time series, e.g. Integrated Water Vapour (IWV), involves the detection of breaks or shifts in the mean value of data. This is an extremely important task since trends estimated from tropospheric data applied nowadays to monitor changes in climate are affected by these breaks. Therefore, there...
Poster
Full-text available
This research focuses on the investigation of the deterministic and stochastic parts of the DORIS (Doppler Orbitography and Radiopositioning Integrated by Satellite) weekly time series aligned to the newest release of ITRF2014. A set of 90 stations was divided into three groups depending on when the data was collected at an individual station: from...
Presentation
Full-text available
Seasonal variations in GNSS position time series can be arise from real geophysical and spurious effect. This research is focused on verification of the following hypothesis: geodetic position time series are characterised by common spatio-temporal seasonal signals which are time changeable with the optimal method for their investigation being Mult...
Article
Full-text available
This paper focuses on the investigation of the deterministic and stochastic parts of the DORIS (Doppler Orbitography and Radiopositioning Integrated by Satellite) weekly time series aligned to the newest release of ITRF2014. A set of 90 stations was divided into three groups depending on when the data was collected at an individual station. To reli...
Article
Full-text available
Long series of Zenith Wet Delay (ZWD) obtained as part of a homogeneous re-processing of Global Positioning System (GPS) solutions constitute a reliable set of data to be assimilated into climate models. The correct stochastic properties, i.e. the noise model of these data have to be identified to assess the real value of ZWD trend uncertainties si...
Article
Full-text available
The inter-comparison of ground gravity measurements and vertical surface displacements enables to better understand the structure, dynamics and evolution of the Earth’s system. Within this research we analyzed the Global Positioning System vertical position time series acquired in the vicinity of the superconducting gravimeters. We estimated of noi...
Poster
Full-text available
In this study, Singular Spectrum Analysis (SSA) along with its multivariate extension MSSA (Multichannel SSA) were used to estimate long-term trend and gravimetric factor at the Chandler wobble frequency from superconducting gravimeter (SG) records. We have used data from seven stations located worldwide and contributing to the International Geodyn...
Poster
Full-text available
Global Positioning System (GPS) position time series contain seasonal signals. Among the others, annual and semi-annual are the most powerful. Widely, these oscillations are modelled as curves with constant amplitudes, using the Weighted Least-Squares (WLS) algorithm. However, in reality, the seasonal signatures vary over time, as their geophysical...
Poster
Full-text available
This research focuses on the investigation of the deterministic and stochastic parts of the DORIS (Doppler Orbitography and Radiopositioning Integrated by Satellite) weekly coordinate time series from the IDS contribution to the ITRF2014A set of 90 stations was divided into three groups depending on when the data was collected at an individual stat...
Presentation
Full-text available
A proper homogenization of tropospheric dataset is indispensable, as the parameters of deterministic part, e.g. trend will be influenced by undetected breaks. Different groups have already used different methods and obtained different estimates - the truth is not known. A synthetic benchmark dataset is a proper way to quantify results given by vari...
Presentation
Full-text available
Most Global Positioning System (GPS) position time series contain annual and semi-annual periods that are routinely modelled as two periodic signals with constant amplitude and phase-lag. However, the amplitudes and phase-lags of seasonal signals vary slightly over time. Also, time series contain specific colored noise. Which methods should we empl...
Presentation
Full-text available
An accurate removal of the seasonal signals from the Global Positioning System (GPS) position time series is beneficial for the accuracy of the derived velocities. In this research, we propose a two-stage solution of the problem of reliable subtraction of seasonal changes. Firstly, we employ the environmental loading models (atmospheric, hydrologic...
Presentation
Full-text available
Nowadays, near real-time Zenith Wet Delay (ZWD) estimates from Global Positioning System (GPS) observations are routinely assimilated into numerical weather prediction (NWP) models to improve the reliability of forecasts. On the other hand, ZWD time series derived from homogeneously re-processed GPS observations over long periods have the potential...
Poster
Full-text available
A synthetic benchmark dataset of Integrated Water Vapour (IWV) was created within the activity of “Data homogenisation” of sub-working group WG3 of COST ES1206 Action. The benchmark dataset was created basing on the analysis of IWV differences retrieved by Global Positioning System (GPS) International GNSS Service (IGS) stations using European Cent...
Presentation
Full-text available
Within the COST Action ES1206 “Advanced Global Navigation Satellite Systems tropospheric products for monitoring severe weather events and climate” (GNSS4SWEC), there was a clear interest and need to homogenize a worldwide Integrated Water Vapour (IWV) dataset retrieved with Global Positioning System (GPS), by correcting (artificial) break points d...
Presentation
Full-text available
In this research, we explored the ability of MSSA application to separate real geophysical effects from spurious effects in GPS time series. For this purpose, we used GPS position changes and environmental loading models. We analysed the topocentric time series from 250 selected stations located worldwide, delivered from Network Solution obtained b...
Article
Full-text available
We estimated the common seasonal signal (annual oscillation) included in the Global Positioning System (GPS) vertical position time series by using Multichannel Singular Spectrum Analysis (MSSA). We employed time series from 24 International GNSS Service (IGS) stations located in Europe which contributed to the newest ITRF2014 (International Terres...
Article
Full-text available
The velocities of the Global Positioning System (GPS) stations are widely employed for numerous geodynamical studies. The aim of this paper is to investigate the reliability of station velocities and to draw reader’s attention that for proper estimates of velocity, we need to consider the optimal character of noise. We focus on a set of 115 Europea...
Presentation
Full-text available
Zenith Total Delay (ZTD) time series, derived from the re-processing of Global Positioning System (GPS) data, provide valuable information for the evaluation of global atmospheric reanalysis products such as ERA-Interim. Identifying the correct noise characteristics in the ZTD time series is an important step to assess the ’true’ magnitude of ZTD t...
Presentation
Full-text available
Offsets due to changes in hardware equipment may artificially under- or overestimate trends and their uncertainties calculated from tropospheric data retrievals processed from Global Navigation Satellite Systems (GNSS) observables, which might potentially be used for climate studies. A homogenization of these tropospheric data is therefore needed a...
Presentation
Full-text available
An accurate estimation of the linear velocity at Global Navigation Satellite System (GNSS) stations is highly desirable. This station velocity is used in geodynamic analyses and for the realization of reference frames. To obtain the best results, it should be estimated simultaneously with all disturbances that are present in time series. In this re...
Article
Full-text available
Zenith Total Delay (ZTD) time series, derived from the re-processing of Global Positioning System (GPS) data, provide valuable information for the evaluation of global atmospheric reanalysis products such as ERA-Interim. Identifying the correct noise characteristics in the ZTD time series is an important step to assess the "true" magnitude of ZTD t...
Poster
Full-text available
The seasonal variations recorded by superconducting gravimeters (SG) may stem from non-tidal ocean loading, atmosphere loading, solid Earth tides, ocean tidal loading, continental water storage loadings and various errors. In this research, we used minute gravity changes from 18 stations located worldwide. The length of SG time series ranged from 4...
Article
Each of the GPS time series that describe changes of topocentric components consists of a deterministic and a stochastic part, which character influences the errors of the deterministic parameters. When concerned with the uncertainties of reliable velocities of permanent satellite station systems, surveys that estimate and take into account any dep...
Presentation
Full-text available
In this research, we show the advantages of novel approach we propose on Global Navigation Satellite System (GNSS) position time series affected by Tohoku undersea megathrust earthquake off the coast of Japan, with a magnitude of Mw 9.0 which took place on 11 March 2011. A novel approach is based on simultaneous estimation of all parameters of post...