Advances in Space Research 

About: Advances in Space Research is an academic journal. The journal publishes majorly in the area(s): Solar wind & Ionosphere. It has an ISSN identifier of 0273-1177. Over the lifetime, 20571 publication(s) have been published receiving 254870 citation(s).

International Reference Ionosphere 2007: Improvements and new parameters

Abstract: The International Reference Ionosphere (IRI), a joint project of URSI and COSPAR, is the de facto international standard for the climatological specification of ionospheric parameters and as such it is currently undergoing registration as Technical Specification (TS) of the International Standardization Organization (ISO). IRI by charter and design is an empirical model based on a wide range of ground and space data. It describes monthly averages of ionospheric densities and temperatures in the altitude range 50–1500 km in the non-auroral ionosphere. Since its inception in 1969 the IRI model has been steadily improved with newer data and with better mathematical descriptions of global and temporal variation patterns. A large number of independent studies have validated the IRI model in comparisons with direct and indirect ionospheric measurements not used in the model development. A comparison with IRI is often one of the first science tasks by an ionospheric satellite or rocket team. This paper describes the latest version of the IRI model, IRI-2007, explaining the most important changes that are being introduced with this version. These include: (1) two new options for the topside electron density, (2) a new model for the topside ion composition, (3) the first-time inclusion of a model for the spread F occurrence probability, (4) a NeuralNet model for auroral E-region electron densities, (5) a model for the plasmaspheric electron temperature, and (6) the latest International Geomagnetic Reference Field (IGRF) model for the computation of magnetic coordinates including their changes due to the secular variation of the magnetic field.

The International Laser Ranging Service

Abstract: The International Laser Ranging Service (ILRS) was established in September 1998 to support programs in geodetic, geophysical, and lunar research activities and to provide the International Earth Rotation Service (IERS) with products important to the maintenance of an accurate International Terrestrial Reference Frame (ITRF) Now in operation for nearly two years, the ILRS develops (1) the standards and specifications necessary for product consistency, and (2) the priorities and tracking strategies required to maximize network efficiency The Service collects, merges, analyzes, archives and distributes satellite and lunar laser ranging data to satisfy a variety of scientific, engineering, and operational needs and encourages the application of new technologies to enhance the quality, quantity, and cost effectiveness of its data products The ILRS works with (1) new satellite missions in the design and building of retroreflector targets to maximize data quality and quantity, and (2) science programs to optimize scientific data yield The ILRS is organized into permanent components: (1) a Governing Board, (2) a Central Bureau, (3) Tracking Stations and Subnetworks, (4) Operations Centers, (5) Global and Regional Data Centers, and (6) Analysis, Lunar Analysis, and Associate Analysis Centers The Governing Board, with broad representation from the international Satellite Laser Ranging (SLR) and Lunar Laser Ranging (LLR) community, provides overall guidance and defines service policies, while the Central Bureau oversees and coordinates the daily service activities, maintains scientific and technological data bases, and facilitates communications Active Working Groups in (1) Missions, (2) Networks and Engineering, (3) Data Formats and Procedures, (4) Analysis, and (5) Signal Processing provide key operational and technical expertise to better exploit current capabilities and to challenge the ILRS participants to keep pace with evolving user needs The ILRS currently includes more than 40 SLR stations, routinely tracking about 20 retroreflector-equipped satellites and the Moon in support of user needs

Application of vegetation index and brightness temperature for drought detection

Abstract: In recent years the National Oceanic and Atmospheric Administration (NOAA) has designed a new AVHRR-based Vegetation Condition Index (VCI) that has showed to be useful for drought detection and tracking. Validations showed that the VCI has excellent ability to detect drought and to measure time of its onset, intensity, duration, and impact on vegetation. The VCI provides accurate drought information not only for well-defined, prolonged, widespread, and intensive droughts, but also for very localized, short-term, and non well-defined droughts. In addition to the VCI, the AVHRR-based observations in thermal bands were used to develop the Temperature Condition Index (TCI). This index was used to determine temperature-related vegetation stress and also stress caused by an excessive wetness. This paper provides principles of these indices, describes data processing, and gives examples of VCI/TCI application in different ecological environments of the United States.

CHAMP mission status

Abstract: The German small satellite CHAMP is on the final track for launch on July 15, 2000 into a circular, nearpolar and 460 km altitude orbit. The satellite carries a number of instruments, partly provided by NASA, CNES and USAF, with synergetic use for precise orbit determination, global gravity and magnetic field recovery, and GPS atmosphere and ionosphere profiling. The mission is projected for a five years' lifetime while the orbit slowly decays to below 300 km altitude. The ground segment is run by DLR for mission operations and by GFZ for mission/science interaction, science data processing, archiving and distribution. Ionosphere profiling is a task of DLR. CHAMP's commissioning phase for system verification, payload data and software calibration/validation is supposed to last nine months, followed by the nominal exploitation phase.

The Orbiting Carbon Observatory (OCO) mission

Abstract: The Orbiting Carbon Observatory (OCO) mission will make the first global, space-based measurements of atmospheric carbon dioxide (CO 2 ) with the precision, resolution, and coverage needed to characterize CO 2 sources and sinks on regional scales. The measurement approach and instrument specifications were determined through an analysis of existing carbon cycle data and a series of observing system simulation experiments. During its 2-year mission, OCO will fly in a 1:15 PM sun-synchronous orbit with a 16-day ground-track repeat time, just ahead of the EOS Aqua platform. It will carry a single instrument that incorporates three bore-sighted high-resolution spectrometers designed to measure reflected sunlight in the 0.76-μm O 2 A-band and in the CO 2 bands at 1.61 and 2.06 μm. Soundings recorded in these three bands will be used to retrieve the column-averaged CO 2 dry air mole fraction ( X CO 2 ). A comprehensive validation program was included in the mission to ensure that the space-based X CO 2 measurements have precisions of ∼0.3% (1 ppm) on regional scales. OCO measurements will be used in global synthesis inversion and data assimilation models to quantify CO 2 sources and sinks. While OCO will have a nominal lifetime of only 2 years, it will serve as a pathfinder for future long-term CO 2 monitoring missions.