Comparative analysis of GOCI ocean color products

by on 22 August 2016in Earth Science and Remote Sensing No comment

The Geostationary Ocean Color Imager (GOCI) is the first geostationary ocean color sensor in orbit that provides bio-optical properties from coastal and open waters around the Korean Peninsula at unprecedented temporal resolution. In this study, we compare the normalized water-leaving radiance (nLw) products generated by the Naval Research Laboratory Automated Processing System (APS) with those produced by the stand-alone software package, the GOCI Data Processing System (GDPS), developed by the Korean Ocean Research & Development Institute (KORDI). Both results are then compared to the nLw measured by the above water radiometer at the Ieodo site. This above-water radiometer is part of the Aerosol Robotic NETwork (AeroNET). The results indicate that the APS and GDPS processed correlates well within the same image slot where the coefficient of determination (r(2)) is higher than 0.84 for all the bands from 412 nm to 745 nm. The agreement between APS and the AeroNET data is higher when compared to the GDPS results. The Root-Mean-Squared-Error (RMSE) between AeroNET and APS data ranges from 0.24 [mW/(cm(2)srmum)] at 555 nm to 0.52 [mW/(cm(2)srmum)] at 412 nm while RMSE between AeroNET and GDPS data ranges from 0.47 [mW/(cm(2)srmum)] at 443 nm to 0.69 [mW/(cm(2)srmum)] at 490 nm.

Related URLs:
http://www.ncbi.nlm.nih.gov/pubmed/26473861

Occurrence and Spatial Extent of HABs on the West Florida Shelf 2002 – Present

by on 22 August 2016in Earth Science and Remote Sensing No comment

Harmful algal blooms (HABs) can lead to severe economic and ecological impacts in coastal areas and can threaten marine life and human health. About three quarters of these toxic blooms are caused by dinoflagellate species. One dinoflagellate species, i.e., Karenia brevis, blooms nearly every year in the Gulf of Mexico, particularly on the West Florida Shelf (WFS), where these blooms cause millions of dollars in socioeconomic damage. In this letter, we use the red band difference (RBD) bloom detection tech- nique for detection of low backscattering phytoplankton blooms, such as K. brevis, and conduct time-series analyses of the spatial extent of these blooms using Moderate Resolution Imaging Spec- troradiometer (MODIS) monthly mean data spanning July 2002 (sensor inception) to September 2014. The time-series results show that the RBD successfully detects the documented HABs in the region, illustrating the seasonal and interannual variability, in- cluding the extensive blooms of 2005 and 2014.

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http://ieeexplore.ieee.org/xpl/articleDetails.jsp?reload=true&arnumber=7160674

Hourly turbidity monitoring using Geostationary Ocean Color Imager fluorescence bands

by on 22 August 2016in Earth Science and Remote Sensing No comment

TheGeostationaryOceanColorimager(GOCI)isthefirstgeostationaryoceancolor satellite sensor that collects hourly images eight times per day during daylight. This high fre- quency image acquisition makes it possible to study more detailed dynamics of red tide blooms, sediment plumes, and colored dissolved organic matter plumes, and can aid in the prediction of biophysical phenomena. We apply the red band difference and the fluorescence line height algo- rithms to GOCI imagery to separate waters with high algal and nonalgal particles and validate the results with the MODIS imagery. We also track optical features using hourly GOCI imagery and assess their movement through comparisons with predicted ocean currents derived from the navy coastal ocean model and tidal data.

Related URLs:
http://remotesensing.spiedigitallibrary.org/article.aspx?articleid=2424313

Preservation of Biomarkers from Cyanobacteria Mixed with Mars-Like Regolith Under Simulated Martian Atmosphere and UV Flux

by on 22 August 2016in Biology & Biotechnology, Earth Science and Remote Sensing No comment

The space mission EXPOSE-R2 launched on the 24th of July 2014 to the International Space Station is carrying the BIOMEX (BIOlogy and Mars EXperiment) experiment aimed at investigating the endurance of extremophiles and stability of biomolecules under space and Mars-like conditions. In order to prepare the analyses of the returned samples, ground-based simulations were carried out in Planetary and Space Simulation facilities. During the ground-based simulations, Chroococcidiopsis cells mixed with two Martian mineral analogues (phyllosilicatic and sulfatic Mars regolith simulants) were exposed to a Martian simulated atmosphere combined or not with UV irradiation corresponding to the dose received during a 1-year-exposure in low Earth orbit (or half a Martian year on Mars). Cell survival and preservation of potential biomarkers such as photosynthetic and photoprotective pigments or DNA were assessed by colony forming ability assays, confocal laser scanning microscopy, Raman spectroscopy and PCR-based assays. DNA and photoprotective pigments (carotenoids) were detectable after simulations of the space mission (570 MJ/m(2) of UV 200-400 nm irradiation and Martian simulated atmosphere), even though signals were attenuated by the treatment. The fluorescence signal from photosynthetic pigments was differently preserved after UV irradiation, depending on the thickness of the samples. UV irradiation caused a high background fluorescence of the Martian mineral analogues, as revealed by Raman spectroscopy. Further investigation will be needed to ensure unambiguous identification and operations of future Mars missions. However, a 3-month exposure to a Martian simulated atmosphere showed no significant damaging effect on the tested cyanobacterial biosignatures, pointing out the relevance of the latter for future investigations after the EXPOSE-R2 mission. Data gathered during the ground-based simulations will contribute to interpret results from space experiments and guide our search for life on Mars.

Related URLs:
http://www.ncbi.nlm.nih.gov/pubmed/26530341

Combined Spectral and Timing Analysis of the Black Hole Candidate MAXI J1659−152, Discovered by MAXI and Swift

by on 9 June 2015in Earth Science and Remote Sensing No comment

We report on X-ray spectral and timing results of a new black hole candidate (BHC), MAXI J1659−152, with an orbital period of 2.41 hr (shortest among BHCs) in a 2010 outburst from 65 Rossi X-ray Timing Explorer (RXTE) observations and 8 simultaneous Swift and RXTE observations. According to the definitions of the spectral states in Remillard and McClintock (2006, ARA&A, 44, 49), most of the observations have been classified into the intermediate state. All of the X-ray broadband spectra can be modeled by a multi-color disk plus a power-law with an exponential cutoff or a multi-color disk plus a Comptonization component. During the initial phase of the outburst, a high-energy cutoff was visible at 30–40 keV. The innermost radius of the disk gradually decreased by a factor of more than 3 from the onset of the outburst, and reached a constant value of 35 d10cos i−1/2 km, where d10 is the distance in units of 10 kpc and i is the inclination. The type-C quasi-periodic oscillation (QPO) frequency varied from 1.6 Hz to 7.3 Hz in association with a change of the innermost radius, while the innermost radius remained constant during the type-B QPO detections at 1.6–4.1 Hz. Hence, we suggest that the origin of the type-B QPOs is different from that of type-C QPOs, the latter of which would originate from the disk truncation radius. Assuming the constant innermost radius in the latter phase of the outburst as the innermost stable circular orbit, the black hole mass in MAXI J1659−152 is estimated to be 3.6–8.0 M⊙ for a distance of 5.3–8.6 kpc and an inclination angle of 60∘–75∘.

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http://pasj.oxfordjournals.org/content/64/2/32.abstract

Imaging Observation of the Earth's Plasmasphere and Ionosphere by EUVI of ISS-IMAP on the International Space Station

by on 9 June 2015in Earth Science and Remote Sensing No comment

At the end of previous century, we succeeded to image the Earth's plasmasphere from the space by EUV spectral range. Then, spacecraft missions were carried out to image the terrestrial EUV emissions. The extreme ultraviolet imagers (EUVIs) on the international space station (ISS) will be launched in 2012. At the altitude of approximately 400 km, two telescopes direct toward the Earth's limb to look the ionosphere and plasmasphere from the inside-out. One telescope detects the terrestrial EUV emission at O+ (83.4 nm), and the other is He+ (30.4 nm). These two EUV emissions are solar-scattered by ionized oxygen and helium, respectively. The maximum spatial and time resolutions are 0.1 degree and 1 minute, respectively. Our observation methods will become standard to probe the Earth's upper atmosphere.

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A Large X-Ray Flare from a Single Weak-Lined T Tauri Star TWA-7 Detected with MAXI GSC

by on 9 June 2015in Earth Science and Remote Sensing No comment

We present a large X-ray flare from a nearby weak-lined T Tauri star TWA-7 detected with the Gas Slit Camera (GSC) on the Monitor of All-sky X-ray Image (MAXI). The GSC captured X-ray flaring from TWA-7 with a flux of 3 × 10 −9 erg cm −2 s −1 in 2–20 keV band during the scan transit starting at 2010-09-07 18:24:30 (UT). The estimated X-ray luminosity at the scan in the energy band is 3 × 10 32 erg s −1 , indicating that the event is among the largest X-ray flares from T Tauri stars. Since MAXI GSC monitors a target only during a scan transit of about a minute per 92 min orbital cycle, the luminosity at the flare peak might have been higher than that detected. At the scan transit, we observed a high X-ray-to-bolometric luminosity ratio, log LX/Lbol = − 0.1 +0.2−0.3 ; i.e., the X-ray luminosity is comparable to the bolometric luminosity. Since TWA-7 has neither an accreting disk nor a binary companion, the observed event implies that none of those are essential to generate such big flares in T Tauri stars.

Related URLs:
http://pasj.oxfordjournals.org/content/63/sp3/S713.abstract

Surface Velocities From Multiple-Tracer Image Sequences

by on 9 June 2015in Earth Science and Remote Sensing No comment

We discuss a new inverse model to estimate surface velocity using an image sequence with more than one tracer. The method employs the global optimal solution technique, which covers an image scene with subarrays or tiles, within which both velocity components are specified as bilinear forms. Substitution into the tracer conservation equation for each tracer yields a system of equations for the velocity field, which is constrained to fit the image data in a least-squares sense over the entire image domain. Solution is achieved iteratively by a Gauss-Seidel method. A numerical model is used as a benchmark to examine the accuracy of this new technique. Image pairs from the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments onboard the NASA Terra and Aqua spacecraft and the hyperspectral imager for the coastal ocean instrument currently onboard the International Space Station are also used to demonstrate the new inverse model with actual ocean data. The derived vector field from MODIS is then compared with the velocity field obtained by the single-tracer technique, and the results are found to be qualitatively equivalent.

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Method for identifying sedimentary bodies from images and its application to mineral exploration

by on 9 June 2015in Earth Science and Remote Sensing No comment

A method is disclosed for identifying a sediment accumulation from an image of a part of the earth's surface. The method includes identifying a topographic discontinuity from the image. A river which crosses the discontinuity is identified from the image. From the image, paleocourses of the river are identified which diverge from a point where the river crosses the discontinuity. The paleocourses are disposed on a topographically low side of the discontinuity. A smooth surface which emanates from the point is identified. The smooth surface is also disposed on the topographically low side of the point.

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Early Results From 4K-Cooled Superconducting Submm Wave Limb Emission Sounder SMILES Onboard ISS/JEM

by on 9 June 2015in Earth Science and Remote Sensing No comment

Early comparison of O3, HCl, and HNO3 L2 products (ver. 005-06-0032) of the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) onboard International Space Station has been conducted. Good agreements are observed among SMILES, SVISAT-1/ACE-FTS, AURA/MLS, and ENVISAT.MIPAS, for O3 and HCl below 45 km. SMILES HNO3 profiles are statistically ~20% higher than ACE-FTS and MIPAS. At higher altitude region, 45-60 km, SMILES O3 and HCl are considerably different from ACE-FTS and/or MLS. It is concluded, although future data updates will be necessary, SMILES O3 and HCl below 45 km are both useful for scientific application with special cautions to the SMILES data quality.

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