The crustal dynamics data information system: A resource to support scientific analysis using space geodesy

Abstract

Since 1982. the Crustal Dynamics Data Information System (CDDTS) has supported the archive and distrihution of geodetic data products acquired by the National Aeronautics and Space Administration (NASA) as well as national and international programs. The CDDIS provides easy, timely, and reliable access to a variety of data sets, products, and information about these data. These measurements. obtained from a global network of nearly 650 instruments at more than 400 distinct sites, include DORIS (Doppler Orbitog~ raphy and Radiopositioning Integrated by Satellite), GNSS (Global Navigation Satellite System), SLR and LLR (Satellite and Lunar Laser Ranging), and VLm (Very Long Baseline Interferometry). The CDDIS data system and its archive have become increasingly important to many national and international science communities, particularly several of the operational services within the International Association of Geodesy (lAG) and its observing system the Global Geoddic Observing System (GGOS), induding the International DORIS Service (IDS), the International GNSS Service (lGS). the International Laser Ranging Service (lLRS), the International VLBI Service for Geodesy and Astrometry (lVS). and the International Earth rotation and Reference frame Service (IERS), Investigations resulting from the data and products available through the CDDIS support research in many aspects of Earth system science and global change. Each month, the CDDTS archives more than one million data and derived product files totaling over 90 Gbytes in volume. In turn. the global user community downloads nearly 1.2 Thytes (over 10.5 million files) of data and products from the CDDTS each month. The requirements of analysts have evolved since the start of the CDDIS; the specialized nature of the system accommodates the enhancements required to support diverse data sets and user needs. This paper discusses the CDDTS. including background information about the system and its. user communities. archive contents. available meradata, and future plans. Published by Elsevier Ltd. on hehalf of COSPAR.

A New Online Service for the Validation of Multi-GNSS Orbits Using SLR

“…Products from all ACs can be included in the GOVUS service, which is one of the major plans for the future development. The dataset necessary for validation consists of: (1) dataset of SLR normal points (delivered by CDDIS [42]); (2) microwave-based discrete satellite positions (EPH files with orbit ephemerides); and (3) GNSS-derived Earth Rotation Parameters (ERP file). First, the files of Normal Points are converted into separated RINEX files including normal points and meteorological data in turn.…”

“…Additionally, the angular characteristic of each laser measurement is included, thus we can investigate the residuals in very broad spectrum of geometrical dependencies: (1) two angles as seen from SLR station point of view: azimuth and elevation; (2) two angles as seen from the satellite: azimuth and nadir ( Figure 1a); and (3) two angles describing the relative location of the Sun, the satellite, and the Earth in the time of observation: satellite argument of latitude with respect to the argument of the Sun (Δu) and the Sun elevation angle above the orbital plane (β) (see Figure 1b). The computational schema is hard-wired The dataset necessary for validation consists of: (1) dataset of SLR normal points (delivered by CDDIS [42]); (2) microwave-based discrete satellite positions (EPH files with orbit ephemerides); and (3) GNSS-derived Earth Rotation Parameters (ERP file). First, the files of Normal Points are converted into separated RINEX files including normal points and meteorological data in turn.…”

Comparisons of IASI-A and AATSR measurements of top-of-atmosphere radiance over an extended period

“…Since these spikes occur during the time of "year end orbit maneuver of ENVISAT" (Noll, 2010) it is likely that these are caused by temporary AATSR geo-location errors and not calibration errors of the AATSR or the IASI-A.…”

A lunar radio experiment with the Parkes radio telescope for the LUNASKA project

“…The only detectable particles are those which intersect the lunar surface at a shallow angle, with the refracted radio emission directed slightly above the surface. As viewed from the Earth, the Askaryan pulse comes from the Moon's apparent edge or limb, with the initial particle originating from a point typically [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] • in the corresponding direction from the Moon [22]. The component of the pulse which escapes the lunar surface has linear polarisation which is typically radial with respect to the Moon.…”

“…The VTEC maps were obtained from the Crustal Dynamics Data Information System (CDDIS) 3 [29], in the IONEX (IONosphere map EXchange) format [30]. A single file in this format specifies the VTEC on a regular grid in geocentric latitude/longitude (i.e.…”