The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Precipitable Water Vapor (PWV) is a good source to monitor precipitation. It is defined by the amount of water vapor present in atmosphere. Traditionally, radiosondes and microwave radiometers were used to derive PWV. However, these devices have poor temporal resolutions and high operational costs. Therefore, GPS signal delay is now widely used for such purposes. The main aim of this paper is to study...
The orbit of TerraSAR-X is strictly controlled and well known. Based on this information, a very high absolute accuracy in geo-locating TerraSAR-X data is possible and has been demonstrated before. In this manuscript, we present an experimental validation of this, demonstrating the very high level of accuracy achievable using only the atmospheric phase delay information provided in the header files...
The Fluorescence Explorer (FLEX) mission has been recently selected as the 8th Earth Explorer by the European Space Agency (ESA). It will be the first mission specifically designed to measure from space vegetation fluorescence emission, by making use of very high spectral resolution imaging spectroscopy techniques. Vegetation fluorescence is the best proxy to actual vegetation photosynthesis which...
Surface albedo is a critical variable in the Earth's energy balance. To evaluate the quality of albedo retrieved from satellite data is crucial. In this study, the direct comparison was carried out to assess the 5-day albedo product retrieved from the Multi-sensor Combined BRDF Inversion (MCBI) model. Different land covers, such as, grassland, deciduous and coniferous forests are considered in the...
This work evaluates the performance of OCO (Orbiting Carbon Observatory) −2 on global observations since its launch in Sep 2014. It is 10%∼30% coverage that could be detected to obtain the concentration of atmospheric carbon dioxide in space dimension. However, about 65% data of OCO-2 has not be utilized to retrieve because of special atmospheric environment, such as thick aerosol depth and low pressure...
This paper evaluates the applicability and achievable SAR accuracy for octahedrons - a combination of eight corner reflectors with a common phase centre. In an experiment at the observatory in Wettzell from July to November 2015 these cost-efficient and mobile radar targets were measured with TerraSAR-X Staring Spotlight and High-Resolution Spotlight. Applying the geodetic stereo SAR concept, octahedrons...
So far, the Greenhouse Gases Observing Satellite (GOSAT) and the Orbiting Carbon Observatory-2 (OCO-2) are the only two missions designed to measure the column-averaged CO2 dry air mole fraction (XCO2). To improve our understanding of global carbon source and sink, these two XCO2 products are compared in this study. The result reveals that the OCO-2 XCO2 product show the wider spatial coverage than...
NASA's Earth Science Technology Office (ESTO) is responsible for the development of advanced technologies to address future Earth science measurement needs. In recent years, ESTO has flown various 1U – 3U CubeSats as a means to prove the applicability of information system and instrument subsystems in support for Earth science Decadal Survey mission concepts. In 2015 as part of the In-Space Validation...
Synthetic aperture radar (SAR) interferometry is a powerful technology for detection and monitoring of slow ground surface movements. Extraction of this information is a complex task. The persistent scatterer pair (PSP) approach was recently proposed to overcome some limitations of standard persistent scatter interferometry. The PSP method exploits only the relative properties of neighboring points...
With the advent of existing high resolution spectrometers in space (GOSAT, GOME-2, OCO-2), global observations of solar induced chlorophyll fluorescence (SIF) became feasible for the first time. The potential of SIF is to provide an independent and more direct proxy for photosynthetic activity and, depending on retrieval methodology, be less susceptible to atmospheric scattering. Empirically, strong...
Sun-induced fluorescence (SIF) is an electromagnetic signal emitted by the chlorophyll of green leaves which has been shown to be a good proxy for plant photosynthetic activity. Recent developments in spaceborne spectrosopy have led to the derivation of the first global maps of SIF from a number of space-based spectrometers. This contribution will provide an overview on the state-of-the-art of terrestrial...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.