Analysis and characterization of the synergistic AIRS and MODIS cloud-cleared radiances     

Hong Zhang  Hung-Lung Huang  Agnes Lim  Robert Holz  Steve Dutcher  Fred Nagle  Liam Gumley  Jinnian Wang  Runhe Shi  Wei Gao 《Frontiers of Earth Science》2010,4(3):363-373

The Atmospheric Infrared Sounder (AIRS) and MODerate-Resolution Imaging Spectroradiometer (MODIS) on board NASA Earth Observing System (EOS) Aqua spacecraft measure the upwelling infrared radiance used for numerous remote-sensing- and climate-related applications. AIRS provides high spectral resolution infrared radiances, while MODIS provides collocated high spatial resolution radiances at 16 broad infrared bands. An optimal algorithm for cloud-clearing has been developed for AIRS cloudy soundings at the University of Wisconsin-Madison, where the spatially and spectrally collocated AIRS and MODIS data has been used to analyze the characteristic of this algorithm. An analysis and characterization of the global AIRS cloud-cleared radiances using the bias and the standard deviation between the cloud-cleared and the nearby clear measurements are studied. Scene inhomogeneity for both land- and water-surface types has been estimated to account for the assessed error. Both monthly and seasonal changes of global AIRS/MODIS cloud-clearing performance also have been analyzed.  相似文献   

Effects of natural and calcined oyster shells on Cd and Pb immobilization in contaminated soils   总被引：5，自引：0，他引：5  

Yong Sik Ok  Sang-Eun Oh  Mahtab Ahmad  Seunghun Hyun  Kwon-Rae Kim  Deok Hyun Moon  Sang Soo Lee  Kyoung Jae Lim  Weon-Tai Jeon  Jae E. Yang 《Environmental Earth Sciences》2010,61(6):1301-1308

In Korea, soils adjacent to abandoned mines are commonly contaminated by heavy metals present in mine tailings. Further, the disposal of oyster shell waste by oyster farm industries has been associated with serious environmental problems. In this study, we attempted to remediate cadmium (Cd)- and lead (Pb)-contaminated soils typical of those commonly found adjacent to abandoned mines using oyster shell waste as a soil stabilizer. Natural oyster shell powder (NOSP) and calcined oyster shell powder (COSP) were applied as soil amendments to immobilize Cd and Pb. The primary components of NOSP and COSP are calcium carbonate (CaCO₃) and calcium oxide (CaO), respectively. X-ray diffraction, X-ray fluorescence and scanning electron microscope analyses conducted in this study revealed that the calcination of NOSP at 770°C converted the less reactive CaCO₃ to the more reactive CaO. The calcination process also decreased the sodium content in COSP, indicating that it was advantageous to use COSP as a liming material in agricultural soil. After 30 days of incubation, we found that the 0.1 N HCl-extractable Cd and Pb contents in soil decreased significantly as a result of an increase in the soil pH and the formation of metal hydroxides. COSP was more effective in immobilizing Cd and Pb in the contaminated soil than NOSP. Overall, the results of this study suggest that oyster shell waste can be recycled into an effective soil ameliorant.  相似文献   

The effect of the wintertime Arctic Oscillation on springtime vegetation over the northern high latitude region   总被引：1，自引：0，他引：1  

Mee-Hyun Cho  Gyu-Ho Lim  Hyo-Jong Song 《Asia-Pacific Journal of Atmospheric Sciences》2014,50(1):567-573

The winter Arctic Oscillation (AO), a major source of climate variability in the Northern Hemisphere, affects winter and the subsequent spring climate over northern high latitude. Such effects are evident even in the 1st eigenmode of the normalized difference vegetation index (NDVI). The impacts of the winter AO is a dipole pattern between Eurasia and North America; positive (negative) values of the winter AO induce warmer (cooler) and high (low) vegetation activity in the following spring over Eurasia (North America). Regarding the time-lagged response of vegetation, the sea surface temperature (SST) and snow cover contribute to maintaining the large-scale circulation anomaly associated with the AO.  相似文献   

Distribution and characteristics of marine habitats in a subpolar bay based on hydroacoustics and bed shear stress estimates—Potter Cove,King George Island,Antarctica     

Anne-Cathrin Wölfl  Chai Heng Lim  H. Christian Hass  Sebastian Lindhorst  Gabriela Tosonotto  Karsten Alexander Lettmann  Gerhard Kuhn  Jörg-Olaf Wolff  Doris Abele 《Geo-Marine Letters》2014,34(5):435-446

Marine habitats worldwide are increasingly pressurized by climate change, especially along the Antarctic Peninsula. Well-studied areas in front of rapidly retreating tidewater glaciers like Potter Cove are representative for similar coastal environments and, therefore, shed light on habitat formation and development on not only a local but also regional scale. The objective of this study was to provide insights into habitat distribution in Potter Cove, King George Island, Antarctica, and to evaluate the associated environmental processes. Furthermore, an assessment concerning the future development of the habitats is provided. To describe the seafloor habitats in Potter Cove, an acoustic seabed discrimination system (RoxAnn) was used in combination with underwater video images and sediment samples. Due to the absence of wave and current measurements in the study area, bed shear stress estimates served to delineate zones prone to sediment erosion. On the basis of the investigations, two habitat classes were identified in Potter Cove, namely soft-sediment and stone habitats that, besides influences from sediment supply and coastal morphology, are controlled by sediment erosion. A future expansion of the stone habitat is predicted if recent environmental change trends continue. Possible implications for the Potter Cove environment, and other coastal ecosystems under similar pressure, include changes in biomass and species composition.  相似文献   

Projected changes in meteorological drought over East Africa inferred from bias-adjusted CMIP6 models     

Ayugi  Brian  Shilenje  Zablon Weku  Babaousmail  Hassen  Lim Kam Sian  Kenny T. C.  Mumo  Richard  Dike  Victor Nnamdi  Iyakaremye  Vedaste  Chehbouni  Abdelghani  Ongoma  Victor 《Natural Hazards》2022,113(2):1151-1176

Natural Hazards - The ongoing global warming has caused unprecedented changes in the climate system, leading to an increase in the intensity and frequency of weather and climate extremes. This...  相似文献   

EChO payload electronics architecture and SW design     

M. Focardi  A. M. Di Giorgio  M. Farina  M. Pancrazzi  R. Ottensamer  T. L. Lim  S. Pezzuto  G. Micela  E. Pace 《Experimental Astronomy》2015,40(2-3):813-839

EChO is a three-modules (VNIR, SWIR, MWIR), highly integrated spectrometer, covering the wavelength range from 0.55 μ m to 11.0 μ m. The baseline design includes the goal wavelength extension to 0.4 μ m while an optional LWIR module extends the range to the goal wavelength of 16.0 μ m. An Instrument Control Unit (ICU) is foreseen as the main electronic subsystem interfacing the spacecraft and collecting data from all the payload spectrometers modules. ICU is in charge of two main tasks: the overall payload control (Instrument Control Function) and the housekeepings and scientific data digital processing (Data Processing Function), including the lossless compression prior to store the science data to the Solid State Mass Memory of the Spacecraft. These two main tasks are accomplished thanks to the Payload On Board Software (P-OBSW) running on the ICU CPUs.  相似文献   

The 69-μm forsterite band as a dust temperature indicator     

J. E.Bowey  M. J.Barlow  F. J.Molster  A. M.Hofmeister  C.Lee  C.Tucker  T.Lim  P. A. R.Ade  L. B. F. M.Waters 《Monthly notices of the Royal Astronomical Society》2002,331(1):L1-L6

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Geological overview and cratering model for the Haughton impact structure,Devon Island,Canadian High Arctic     

Gordon R. Osinski  Pascal Lee  John G. Spray  John Parnell  Darlene S. S. Lim  Theodore E. Bunch  Charles S. Cockell  Brian Glass 《Meteoritics & planetary science》2005,40(12):1759-1776

Abstract— The Haughton impact structure has been the focus of systematic, multi‐disciplinary field and laboratory research activities over the past several years. Regional geological mapping has refined the sedimentary target stratigraphy and constrained the thickness of the sedimentary sequence at the time of impact to ?1880 m. New ⁴⁰Ar–³⁹Ar dates place the impact event at ?39 Ma, in the late Eocene. Haughton has an apparent crater diameter of ?23 km, with an estimated rim (final crater) diameter of ?16 km. The structure lacks a central topographic peak or peak ring, which is unusual for craters of this size. Geological mapping and sampling reveals that a series of different impactites are present at Haughton. The volumetrically dominant crater‐fill impact melt breccias contain a calcite‐anhydrite‐silicate glass groundmass, all of which have been shown to represent impact‐generated melt phases. These impactites are, therefore, stratigraphically and genetically equivalent to coherent impact melt rocks present in craters developed in crystalline targets. The crater‐fill impactites provided a heat source that drove a post‐impact hydrothermal system. During this time, Haughton would have represented a transient, warm, wet microbial oasis. A subsequent episode of erosion, during which time substantial amounts of impactites were removed, was followed by the deposition of intra‐crater lacustrine sediments of the Haughton Formation during the Miocene. Present‐day intra‐crater lakes and ponds preserve a detailed paleoenvironmental record dating back to the last glaciation in the High Arctic. Modern modification of the landscape is dominated by seasonal regional glacial and niveal melting, and local periglacial processes. The impact processing of target materials improved the opportunities for colonization and has provided several present‐day habitats suitable for microbial life that otherwise do not exist in the surrounding terrain.  相似文献   

The effect of dissipation on the generation of density structure by magnetohydrodynamic waves     

A. J. Lim  S. A. E. G. Falle  T. W. Hartquist 《Monthly notices of the Royal Astronomical Society》2005,357(2):461-470

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Performance of Jacobi preconditioning in Krylov subspace solution of finite element equations     

F.‐H. Lee  K.K. Phoon  K.C. Lim  S.H. Chan 《国际地质力学数值与分析法杂志》2002,26(4):341-372

This paper examines the performance of the Jacobi preconditioner when used with two Krylov subspace iterative methods. The number of iterations needed for convergence was shown to be different for drained, undrained and consolidation problems, even for similar condition number. The differences were due to differences in the eigenvalue distribution, which cannot be completely described by the condition number alone. For drained problems involving large stiffness ratios between different material zones, ill‐conditioning is caused by these large stiffness ratios. Since Jacobi preconditioning operates on degrees‐of‐freedom, it effectively homogenizes the different spatial sub‐domains. The undrained problem, modelled as a nearly incompressible problem, is much more resistant to Jacobi preconditioning, because its ill‐conditioning arises from the large stiffness ratios between volumetric and distortional deformational modes, many of which involve the similar spatial domains or sub‐domains. The consolidation problem has two sets of degrees‐of‐freedom, namely displacement and pore pressure. Some of the eigenvalues are displacement dominated whereas others are excess pore pressure dominated. Jacobi preconditioning compresses the displacement‐dominated eigenvalues in a similar manner as the drained problem, but pore‐pressure‐dominated eigenvalues are often over‐scaled. Convergence can be accelerated if this over‐scaling is recognized and corrected for. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献