ALBERT

Description: To estimate the kinematics of the SIRGAS reference frame, the Deutsches Geodätisches Forschungsinstitut (DGFI) as the IGS Regional Network Associate Analysis Centre for SIRGAS (IGS RNNAC SIR), yearly computes a cumulative (multi-year) solution containing all available weekly solutions delivered by the SIRGAS analysis centres. These cumulative solutions include those models, standards, and strategies widely applied at the time in which they were computed and cover different time spans depending on the availability of the weekly solutions. This data set corresponds to the multi-year solution SIR11P01. It is based on the combination of the weekly normal equations covering the time span from 2000-01-02 (GPS week 1043) to 2011-04-16 (GPS week 1631), when the IGS08 reference frame was introduced. It refers to ITRF2008, epoch 2005.0 and contains 230 stations with 269 occupations. Its precision was estimated to be ±1.0 mm (horizontal) and ±2.4 mm (vertical) for the station positions, and ±0.7 mm/a (horizontal) and ±1.1 mm/a (vertical) for the constant velocities. Computation strategy and results are in detail described in Sánchez and Seitz (2011). The IGS RNAAC SIR computation of the SIRGAS reference frame is possible thanks to the active participation of many Latin American and Caribbean colleagues, who not only make the measurements of the stations available, but also operate SIRGAS analysis centres processing the observational data on a routine basis (more details in http://www.sirgas.org). The achievements of SIRGAS are a consequence of a successful international geodetic cooperation not only following and meeting concrete objectives, but also becoming a permanent and self-sustaining geodetic community to guarantee quality, reliability, and long-term stability of the SIRGAS reference frame. The SIRGAS activities are strongly supported by the International Association of Geodesy (IAG) and the Pan-American Institute for Geography and History (PAIGH). The IGS RNAAC SIR highly appreciates all this support.

Description: Strong earthquakes cause large changes in the station positions and velocities of the geodetic reference stations; i.e., the global ITRF (International Terrestrial Reference Frame) and its regional densifications like SIRGAS (Sistema de Referencia Geocéntrico para Las Américas) in Latin America and the Caribbean. To ensure the long-term stability of the geodetic reference frames, the transformation of station positions between different epochs requires the computation of reliable continuous surface deformation (or velocity) models. This data set contains the new continental continuous crustal deformation model VEMOS2015 (Velocity Model for SIRGAS 2015) for Latin America and the Caribbean inferred from GNSS (GPS+GLONASS) measurements gained after the strong earthquakes occurred in 2010 in Chile and Mexico. It is based on a multi-year velocity solution for a network of 456 continuously operating GNSS stations covering a five years period from March 14, 2010 to April 11, 2015. VEMOS2015 is computed using the least square collocation (LSC) approach with empirically determined covariance functions.

Description: We provide a present-day surface-kinematics model for the Alpine region and surroundings based on a high-level data analysis of a network of about 300 continuously operating GNSS (GPS+GLONASS) stations with observations collected over 12.4 years. Based on the network station velocities, a continuous kinematic field is derived using a geodetic least-squares collocation approach with empirically determined covariance functions. Main results are (1) a deformation model, (2) a continuous surface-kinematic (velocity) field, and (3) a strain field consistently assessed for the entire Alpine mountain belt. The core contribution of this work is the homogeneous analysis of a large number of freely available data from GNSS stations located in the Alpine region, using unified processing standards and a common reference frame for the complete time-span covered by the observations. The GNSS network solution refers to the reference frame IGb08, epoch 2010.0. The mean precision of the station positions at the reference epoch is ±1.1 mm in N and E and ±2.3 mm in height. The mean precision of the station velocities is ±0.2 mm/a in N and E and ±0.4 mm/a in the height. The averaged accuracy of the horizontal and vertical deformation models inferred from the pointwise station velocities are ±0.2 mm/a and ±0.3 mm/a, respectively. The deformation model as well as the continuous velocity and strain fields are given in a grid of 25 km x 25 km covering the region between longitudes 4°E and 16°E and latitudes 43°N and 49°N.

Description: The SIRGAS reference frame realization (SIR17P01) covers the period from April 17, 2011 (GPS week 1632) to January 28, 2017 (GPS week 1933). It includes only weekly solutions referring to the IGS08/IGb08 reference frame. This new SIRGAS realization is aligned to the IGS14 reference frame and it is consistent with the igs14.atx ground antenna calibrations. SIR17P01 includes positions and velocities of 345 stations referring tothe IGS14, epoch 2015.0. Its estimated precision is ±1.2 mm (horizontal) and ±2.5 mm (vertical) for the station positions at the reference epoch, and ±0.7 mm/a (horizontal) and ±1.1 mm/a (vertical)for the velocities.

Description: We provide a present-day continuous surface-kinematics model for the entire Latin American and Caribbean region (VEMOS2017). VEMOS2017 was derived from pointwise station velocities inferred at 515 geodetic sites from January 1, 2014 to January 28, 2017 using a geodetic least-squares collocation approach with empirically determined covariance functions. VEMOS2017 describes the present-day deformation in Latin America and the Caribbean and continues the surface-kinematics model represented by VEMOS2015, which is valid from March 14, 2010 to April 11, 2015 (see doi:10.1594/PANGAEA.863132). VEMOS2017 covers the region from 120°W, 55°S to 35°W, 32°N with a spatial resolution of 1° x 1°. The average uncertainty of VEMOS2017 is assessed to be ±1.0 mm/a in the north-south direction and ±1.7 mm/a in the east-west direction. The maximum uncertainty values (up to ±15 mm/a) occur at the zones affected by recent strong earthquakes (in the Maule area, the northern part of Chile, Ecuador and Costa Rica). The best uncertainty values (about ±0.1 mm/a) result in the stable eastern part of the South American plate.