4,347 research outputs found
System study of the carbon dioxide observational platform system (CO-OPS): Project overview
The resulting options from a system study for a near-space, geo-stationary, observational monitoring platform system for use in the Department of Energy's (DOE) National Carbon Dioxide Observational Platform System (CO-OPS) on the greenhouse effect are discussed. CO-OPS is being designed to operate continuously for periods of up to 3 months in quasi-fixed position over most global regional targets of interest and could make horizon observations over a land-sea area of circular diameter up to about 600 to 800 statute miles. This affords the scientific and engineering community a low-cost means of operating their payloads for monitoring the regional parameters they deem relevant to their investigations of the carbon dioxide greenhouse effect at one-tenth the cost of most currently utilized comparable remote sensing techniques
On-orbit structural dynamic performance of a 15-meter microwave radiometer antenna
The on-orbit structural dynamic performance of a microwave radiometer antenna for Earth science applications is addressed. The radiometer is one of the Earth-observing instruments aboard a proposed geostationary platform as part of the Mission to the Planet Earth. A sequential approach is presented for assessing the ability of an antenna structure to retain its geometric shape subject to a representative onboard disturbance. This approach includes establishing the structural requirements of the antenna, developing the structural and disturbance models, performing modal and forced response analyses, and evaluating the resulting distortions in terms of the antenna's ability to meet stringent structural performance requirements. Two antenna configurations are discussed: free-flying and platform-mounted. These configurations are analyzed for a representative disturbance function which simulates rotation of the subreflector in order to perform a raster-type scan of the Earth disk. Results show that the scanning maneuver modeled would not induce antenna structural errors outside the specified limits
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Concepts for a geostationary-like polar missions
An evidence-led scientific case for development of a space-based polar remote sensing platform at geostationary-like (GEO-like) altitudes is developed through methods including a data user survey. Whilst a GEO platform provides a near static perspective, multiple platforms are required to provide circumferential coverage. Systems for achieving GEO-like polar observation likewise require multiple platforms however the perspective is non-stationery. A key choice is between designs that provide complete polar view from a single platform at any given instant, and designs where this is obtained by compositing partial views from multiple sensors. Users foresee an increased challenge in extracting geophysical information from composite images and consider the use of non-composited images advantageous. Users also find the placement of apogee over the pole to be preferable to the alternative scenarios. Thus, a clear majority of data users find the “Taranis” orbit concept to be better than a critical inclination orbit, due to the improved perspective offered. The geophysical products that would benefit from a GEO-like polar platform are mainly estimated from radiances in the visible/near infrared and thermal parts of the electromagnetic spectrum, which is consistent with currently proven technologies from GEO. Based on the survey results, needs analysis, and current technology proven from GEO, scientific and observation requirements are developed along with two instrument concepts with eight and four channels, based on Flexible Combined Imager heritage. It is found that an operational system could, mostly likely, be deployed from an Ariane 5 ES to a 16-hour orbit, while a proof-of-concept system could be deployed from a Soyuz launch to the same orbit
Precipitation products from the hydrology SAF
Abstract. The EUMETSAT Satellite Application Facility on Support to Operational Hydrology and Water Management (H-SAF) was established by the EUMETSAT Council on 3 July 2005, starting activity on 1 September 2005. The Italian Meteorological Service serves as Leading Entity on behalf of twelve European member countries. H-SAF products include precipitation, soil moisture and snow parameters. Some products are based only on satellite observations, while other products are based on the assimilation of satellite measurements/products into numerical models. In addition to product development and generation, H-SAF includes a product validation program and a hydrological validation program that are coordinated, respectively, by the Italian Department of Civil Protection and by the Polish Institute of Meteorology and Water Management. The National Center of Aeronautical Meteorology and Climatology (CNMCA) of the Italian Air Force is responsible for operational product generation and dissemination. In this paper we describe the H-SAF precipitation algorithms and products, which have been developed by the Italian Institute of Atmospheric Sciences and Climate (in collaboration with the international community) and by CNMCA during the Development Phase (DP, 2005–2010) and the first Continuous Development and Operations Phase (CDOP-1, 2010–2012). The precipitation products are based on passive microwave measurements obtained from radiometers onboard different sun-synchronous low-Earth-orbiting satellites (especially, the SSM/I and SSMIS radiometers onboard DMSP satellites and the AMSU-A + AMSU-B/MHS radiometer suites onboard EPS-MetOp and NOAA-POES satellites), as well as on combined infrared/passive microwave measurements in which the passive microwave precipitation estimates are used in conjunction with SEVIRI images from the geostationary MSG satellite. Moreover, the H-SAF product generation and dissemination chain and independent product validation activities are described. Also, the H-SAF program and its associated activities that currently are being carried out or are planned to be performed within the second CDOP phase (CDOP-2, 2012–2017) are presented in some detail. Insofar as CDOP-2 is concerned, it is emphasized that all algorithms and processing schemes will be improved and enhanced so as to extend them to satellites that will be operational within this decade – particularly the geostationary Meteosat Third Generation satellites and the low-Earth-orbiting Core Observatory of the international Global Precipitation Measurement mission. Finally, the role of H-SAF within the international science and operations community is explained.</p
Solar and Heliospheric Physics with the Square Kilometre Array
The fields of solar radiophysics and solar system radio physics, or radio
heliophysics, will benefit immensely from an instrument with the capabilities
projected for SKA. Potential applications include interplanetary scintillation
(IPS), radio-burst tracking, and solar spectral radio imaging with a superior
sensitivity. These will provide breakthrough new insights and results in topics
of fundamental importance, such as the physics of impulsive energy releases,
magnetohydrodynamic oscillations and turbulence, the dynamics of post-eruptive
processes, energetic particle acceleration, the structure of the solar wind and
the development and evolution of solar wind transients at distances up to and
beyond the orbit of the Earth. The combination of the high spectral, time and
spatial resolution and the unprecedented sensitivity of the SKA will radically
advance our understanding of basic physical processes operating in solar and
heliospheric plasmas and provide a solid foundation for the forecasting of
space weather events.Comment: 15 pages, Proceedings of Advancing Astrophysics with the Square
Kilometre Array (AASKA14). 9 -13 June, 2014. Giardini Naxos, Italy. Online at
http://pos.sissa.it/cgi-bin/reader/conf.cgi?confid=215, id.16
Potential of using remote sensing techniques for global assessment of water footprint of crops
Remote sensing has long been a useful tool in global applications, since it provides physically-based, worldwide, and consistent spatial information. This paper discusses the potential of using these techniques in the research field of water management, particularly for ‘Water Footprint’ (WF) studies. The WF of a crop is defined as the volume of water consumed for its production, where green and blue WF stand for rain and irrigation water usage, respectively. In this paper evapotranspiration, precipitation, water storage, runoff and land use are identified as key variables to potentially be estimated by remote sensing and used for WF assessment. A mass water balance is proposed to calculate the volume of irrigation applied, and green and blue WF are obtained from the green and blue evapotranspiration components. The source of remote sensing data is described and a simplified example is included, which uses evapotranspiration estimates from the geostationary satellite Meteosat 9 and precipitation estimates obtained with the Climatic Prediction Center Morphing Technique (CMORPH). The combination of data in this approach brings several limitations with respect to discrepancies in spatial and temporal resolution and data availability, which are discussed in detail. This work provides new tools for global WF assessment and represents an innovative approach to global irrigation mapping, enabling the estimation of green and blue water use
Carbon Dioxide Observational Platform System (CO-OPS), feasibility study
The Carbon Dioxide Observational Platform System (CO-OPS) is a near-space, geostationary, multi-user, unmanned microwave powered monitoring platform system. This systems engineering feasibility study addressed identified existing requirements such as: carbon dioxide observational data requirements, communications requirements, and eye-in-the-sky requirements of other groups like the Defense Department, the Forestry Service, and the Coast Guard. In addition, potential applications in: earth system science, space system sciences, and test and verification (satellite sensors and data management techniques) were considered. The eleven month effort is summarized. Past work and methods of gathering the required observational data were assessed and rough-order-of magnitude cost estimates have shown the CO-OPS system to be most cost effective (less than $30 million within a 10 year lifetime). It was also concluded that there are no technical, schedule, or obstacles that would prevent achieving the objectives of the total 5-year CO-OPS program
Observation requirements for unmanned planetary missions, part 2
Observation requirements for unmanned planetary mission
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Observational needs of sea surface temperature
Sea surface temperature (SST) is a fundamental physical variable for understanding, quantifying and predicting complex interactions between the ocean and the atmosphere. Such processes determine how heat from the sun is redistributed across the global oceans, directly impacting large- and small-scale weather and climate patterns. The provision of daily maps of global SST for operational systems, climate modeling and the broader scientific community is now a mature and sustained service coordinated by the Group for High Resolution Sea Surface Temperature (GHRSST) and the CEOS SST Virtual Constellation (CEOS SST-VC). Data streams are shared, indexed, processed, quality controlled, analyzed, and documented within a Regional/Global Task Sharing (R/GTS) framework, which is implemented internationally in a distributed manner. Products rely on a combination of low-Earth orbit infrared and microwave satellite imagery, geostationary orbit infrared satellite imagery, and in situ data from moored and drifting buoys, Argo floats, and a suite of independent, fully characterized and traceable in situ measurements for product validation (Fiducial Reference Measurements, FRM). Research and development continues to tackle problems such as instrument calibration, algorithm development, diurnal variability, derivation of high-quality skin and depth temperatures, and areas of specific interest such as the high latitudes and coastal areas. In this white paper, we review progress versus the challenges we set out 10 years ago in a previous paper, highlight remaining and new research and development challenges for the next 10 years (such as the need for sustained continuity of passive microwave SST using a 6.9 GHz channel), and conclude with needs to achieve an integrated global high-resolution SST observing system, with focus on satellite observations exploited in conjunction with in situ SSTs. The paper directly relates to the theme of Data Information Systems and also contributes to Ocean Observing Governance and Ocean Technology and Networks within the OceanObs2019 objectives. Applications of SST contribute to all the seven societal benefits, covering Discovery; Ecosystem Health & Biodiversity; Climate Variability & Change; Water, Food, & Energy Security; Pollution & Human Health; Hazards and Maritime Safety; and the Blue Economy
ALMA Observations of Asteroid 3 Juno at 60 Kilometer Resolution
We present Atacama Large Millimeter/submillimeter Array (ALMA) 1.3 mm
continuum images of the asteroid 3 Juno obtained with an angular resolution of
0.042 arcseconds (60 km at 1.97 AU). The data were obtained over a single 4.4
hr interval, which covers 60% of the 7.2 hr rotation period, approximately
centered on local transit. A sequence of ten consecutive images reveals
continuous changes in the asteroid's profile and apparent shape, in good
agreement with the sky projection of the three-dimensional model of the
Database of Asteroid Models from Inversion Techniques. We measure a geometric
mean diameter of 259pm4 km, in good agreement with past estimates from a
variety of techniques and wavelengths. Due to the viewing angle and inclination
of the rotational pole, the southern hemisphere dominates all of the images.
The median peak brightness temperature is 215pm13 K, while the median over the
whole surface is 197pm15 K. With the unprecedented resolution of ALMA, we find
that the brightness temperature varies across the surface with higher values
correlated to the subsolar point and afternoon areas, and lower values beyond
the evening terminator. The dominance of the subsolar point is accentuated in
the final four images, suggesting a reduction in the thermal inertia of the
regolith at the corresponding longitudes, which are possibly correlated to the
location of the putative large impact crater. These results demonstrate ALMA's
potential to resolve thermal emission from the surface of main belt asteroids,
and to measure accurately their position, geometric shape, rotational period,
and soil characteristics.Comment: 8 pages, 3 figures, 2 tables, accepted for publication in the
Astrophysical Journal Letter
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