791 research outputs found
Optical Remote Sensing Of Snow On Sea Ice: Ground Measurements, Satellite Data Analysis, And Radiative Transfer Modeling
Thesis (Ph.D.) University of Alaska Fairbanks, 2002The successful launch of the Terra satellite on December 18, 1999 opened a new era of earth observation from space. This thesis is motivated by the need for validation and promotion of the use of snow and sea ice products derived from MODIS, one of the main sensors aboard the Terra and Aqua satellites. Three cruises were made in the Southern Ocean, in the Ross, Amundsen and Bellingshausen seas. Measurements of all-wave albedo, spectral albedo, BRDF, snow surface temperature, snow grain size, and snow stratification etc. were carried out on pack ice floes and landfast ice. In situ measurements were also carried out concurrently with MODIS. The effect of snow physical parameters on the radiative quantities such as all-wave albedo, spectral albedo and bidirectional reflectance are studied using statistical techniques and radiative transfer modeling, including single scattering and multiple scattering. The whole thesis consists of six major parts. The first part (chapter 1) is a review of the present research work on the optical remote sensing of snow. The second part (chapter 2) describes the instrumentation and data-collection of ground measurements of all-wave albedo, spectral albedo and bidirectional reflectance distribution function (BRDF) of snow and sea ice in the visible-near-infrared (VNIR) domain in Western Antarctica. The third part (chapter 3) contains a detailed multivariate correlation and regression analysis of the measured radiative quantities with snow physical parameters such as snow density, surface temperature, single and composite grain size and number density. The fourth part (chapter 4) describes the validation of MODIS satellite data acquired concurrently with the ground measurements. The radiances collected by the MODIS sensor are converted to ground snow surface reflectances by removing the atmospheric effect using a radiative transfer algorithm (6S). Ground measured reflectance is corrected for ice concentration at the subpixel level so that the in situ and space-borne measured reflectance data are comparable. The fifth part (chapter 5) investigates the single scattering properties (extinction optical depth, single albedo, and the phase function or asymmetry factor) of snow grains (single or composite), which were calculated using the geometrical optical method. A computer code, GOMsnow, is developed and is tested against benchmark results obtained from an exact Mie scattering code (MIE0) and a Monte Carlo code. The sixth part (chapter 6) describes radiative transfer modeling of spectral albedo using a multi-layer snow model with a multiple scattering algorithm (DISORT). The effect of snow stratification on the spectral albedo is explored. The vertical heterogeneity of the snow grain-size and snow mass density is investigated. It is found that optical remote sensing of snow physical parameters from satellite measurements should take the vertical variation of snow physical parameters into account. The albedo of near-infrared bands is more sensitive to the grain-size at the very top snow layer (<5cm), while the albedo of the visible bands is sensitive to the grain-size of a much thicker snow layer. Snow parameters (grain-size, for instance) retrieved with near-infrared channels only represent the very top snow layer (most probably 1--3 cm). Multi-band measurements from visible to near-infrared have the potential to retrieve the vertical profile of snow parameters up to a snow depth limited by the maximum penetration depth of blue light
Industrial Agglomeration, Production Networks and FDI Promotion The Case Study of China
Chinas Industrial clustering is a distinguished economic phenomenon over the last 20 years. It began to enter into its fast track in the mid-1990s and developed rapidly in recent years. Both market-driven force and government-driven force contribute to Chinese industrial clusters. The opening and stable macroeconomic policies create a favorable climate for the industrial clustering. Local government has made its contribution to construction on both hardware and software environments for industrial clusters. The major contribution of FDI to the local industrial clustering lies in helping integrating Chinese domestic industries into international division of labor and at the same time forging a relatively integrated production chain for Chinese domestic industries. At present, China has stepped into the new phase of industrial clusters upgrading. Chinese government is gradually improving the local software infrastructure for industry clustering.Industrial Agglomeration, China, Production Networks, FDI, foreign direct investment
Monitoring Kilauea Volcano’s Eruption in 2018 Using Various Remote Sensing Techniques
Monitoring volcanic eruptions is essential, as early warnings can be issued in case of emergency. In this study, we used Sentinel-1-A InSAR, Landsat 7 & 8 thermal infrared and airborne LiDAR to monitor the Kilauea volcano’s East Rift Zone (ERZ) eruption of 2018
Identification of Heavy Metal Contaminants in the Upper Clark Fork River Basin Using Laser Induced Spectroscopy and Hyperspectral Spectroscopy
The Upper Clark Fork River Basin is home to many current and abandoned mining sites which contribute to the presence of heavy metals. Heavy metals on surface sediments can harm human and ecological health, so it is important to identify these contaminants for removal.
Laser Induced Breakdown Spectroscopy (LIBS) is an active spectroscopy method because it uses a laser pulse to remove a small amount of mass through laser ablation. As the electrons return to their ground states, the unique spectral signatures and intensity can determine the percentage of the element in the sample.
Hyperspectral Spectroscopy (HS) is a passive method that uses natural light reflected from the sample to determine the range and concentration of the wavelength emitted. The resulting plot compares reflectance versus wavelength. HS can be applied to an airborne survey
Applications of SAR Interferometry in Earth and Environmental Science Research
This paper provides a review of the progress in regard to the InSAR remote sensing technique and its applications in earth and environmental sciences, especially in the past decade. Basic principles, factors, limits, InSAR sensors, available software packages for the generation of InSAR interferograms were summarized to support future applications. Emphasis was placed on the applications of InSAR in seismology, volcanology, land subsidence/uplift, landslide, glaciology, hydrology, and forestry sciences. It ends with a discussion of future research directions
An Investigation on the Influence of a Biofilm Fertilizer on Plant Growth and Soil Geophysical Properties
A biofilm is a grouping of one or more types of microorganisms in which cells stick together. Atmospheric nitrogen (N2) can be converted into ammonia (NH3) by organisms in a process called biological nitrogen fixation, becoming more bioavailable for plants to use. Anabaena cylindrica is a non-toxic nitrogen-fixing cyanobacteria (NFC) that has been proposed for use as a biofertilizer.https://digitalcommons.mtech.edu/urp_aug_2017/1009/thumbnail.jp
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