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<p> This dissertation presents the collection and processing of dense high-precision geode- tic data across major faults throughout Southern California. The results are used to inform numerical models of the long-term slip rate and interseismic behavior of these faults, as well as their frictional and rheological properties at shallow depths. The data include campaign surveys of dense networks of GPS monuments crossing the faults, and Interferometric Synthetic Aperture Radar (InSAR) observations from ENVISAT. Using a Bayesian framework, we first assess to what extent these data constrain relative fault slip rates on the San Andreas and San Jacinto faults, and show that the inferred parameters depend critically on the assumed fault geometry. We next look in detail at near-field observations of strain across the San Jacinto fault, and show that the source of this strain may be either deep anomalous creep or a new form of shallow, distributed yielding in the top few kilometers of the crust. On the San Andreas fault, we show that this type of shallow yielding does occur, and its presence or absence is controlled by variations in the local normal stress that result from subtle bends in the fault. Finally, we investigate shallow creep on the Imperial fault, and show that thanks to observations from all parts of the earthquake cycle it is now possible to obtain a strong constraint on the shallow frictional rheology and depth of the material responsible for creep. The results also suggest activity on a hidden fault to the West, whose existence has been previously suggested but never confirmed.</p>

<p> Savannas are mixed tree-grass systems and as one of the world's largest biomes represent an important component of the Earth system affecting water and energy balances, carbon sequestration and biodiversity as well as supporting large human populations. Savanna vegetation structure and its distribution, however, may change because of major anthropogenic disturbances from climate change, wildfire, agriculture, and livestock production. The overstory and understory may have different water use strategies, different nutrient requirements and have different responses to fire and climate variation. The accurate measurement of the spatial distribution and structure of the overstory and understory are essential for understanding the savanna ecosystem. </p><p> This project developed a workflow for separating the dynamics of the overstory and understory fractional cover in savannas at the continental scale (Australia, South America, and Africa). Previous studies have successfully separated the phenology of Australian savanna vegetation into persistent and seasonal greenness using time series decomposition, and into fractions of photosynthetic vegetation (PV), non-photosynthetic vegetation (NPV) and bare soil (BS) using linear unmixing. This study combined these methods to separate the understory and overstory signal in both the green and senescent phenological stages using remotely sensed imagery from the MODIS (MODerate resolution Imaging Spectroradiometer) sensor. The methods and parameters were adjusted based on the vegetation variation.</p><p> The workflow was first tested at the Australian site. Here the PV estimates for overstory and understory showed best performance, however NPV estimates exhibited spatial variation in validation relationships. At the South American site (Cerrado), an additional method based on frequency unmixing was developed to separate green vegetation components with similar phenology. When the decomposition and frequency methods were compared, the frequency method was better for extracting the green tree phenology, but the original decomposition method was better for retrieval of understory grass phenology. Both methods, however, were less accurate than in the Cerrado than in Australia due to intermingling and intergrading of grass and small woody components. </p><p> Since African savanna trees are predominantly deciduous, the frequency method was combined with the linear unmixing of fractional cover to attempt to separate the relatively similar phenology of deciduous trees and seasonal grasses. The results for Africa revealed limitations associated with both methods. There was spatial and seasonal variation in the spectral indices used to unmix fractional cover resulting in poor validation for NPV in particular. The frequency analysis revealed significant phase variation indicative of different phenology, but these could not be clearly ascribed to separate grass and tree components. </p><p> Overall findings indicate that site-specific variation and vegetation structure and composition, along with MODIS pixel resolution, and the simple vegetation index approach used was not robust across the different savanna biomes. The approach showed generally better performance for estimating PV fraction, and separating green phenology, but there were major inconsistencies, errors and biases in estimation of NPV and BS outside of the Australian savanna environment.</p>

Remote sensing is being used in agriculture for crop management. Ground based remote sensing data acquisition system was used for collection of high spatial and temporal resolution data for irrigated broccoli crop. The system was composed of a small cart that ran back and forth on a rail system that was mounted on a linear move irrigation system. The cart was equipped with a sensor that had 4 discrete wavelengths; 550 nm, 660 nm, 720 nm, and 810 nm, and an infrared thermometer, all had 10 nm bandwidth. A global positioning system was used to indicate the cart position. The study consisted of two parts; the first was to evaluate remotely sensed reflectance and indices in broccoli during the growing season, and determine whether remotely sensed indices or standard deviation of indices can distinguish between nitrogen and water stress in broccoli, and the second part of the study was to evaluate remotely sensed indices and standard deviation of remotely sensed indices in broccoli during daily changes in solar zenith angle. Results indicated that nitrogen was detected using Ratio Vegetation index, RVI, Normalized Difference Vegetation Index, NDVI, Canopy Chlorophyll Concentration Index, CCCI, and also using the reflectance in the Near-Infrared, NIR, bands. The Red reflectance band capability of showing stress was not as clear as the previous indices and bands reflectance. The Canopy Chlorophyll Concentration Index, CCCI, was the most successful index. The Crop Water Stress Index was able to detect water stress but it was highly affected by the solar zenith angle change along the day.

This paper describes the development, characterization, and modeling of a Tunable Filter Camera (TFC). The TFC is a new multispectral instrument with electronically tuned spectral filtering and low-light-level sensitivity. It represents a hybrid between hyperspectral and multispectral imaging spectrometers that incorporates advantages from each, addressing issues such as complexity, cost, lack of sensitivity, and adaptability. These capabilities allow the TFC to be applied to low-altitude video surveillance for real-time spectral and spatial target detection and image exploitation. Described herein are the theory and principles of operation for the TFC, which includes a liquid crystal tunable filter, an intensified CCD, and a custom apochromatic lens. The results of proof-of-concept testing, and characterization of two prototype cameras are included, along with a summary of the design analyses for the development of a multiple-channel system. A significant result of this effort was the creation of a system-level model, which was used to facilitate development and predict performance. It includes models for the liquid crystal tunable filter and intensified CCD. Such modeling was necessary in the design of the system and is useful for evaluation of the system in remote-sensing applications. Also presented are characterization data from component testing, which included quantitative results for linearity, signal to noise ratio (SNR), linearity, and radiometric response. These data were used to help refine and validate the model. For a pre-defined source, the spatial and spectral response, and the noise of the camera, system can now be predicted. The innovation that sets this development apart is the fact that this instrument has been designed for integrated, multi-channel operation for the express purpose of real-time detection/identification in low-light-level conditions. Many of the requirements for the TFC were derived from this mission. In order to provide background for the design requirements for the TFC development, the mission and principles of operation behind the multi-channel system will be reviewed. Given the combination of the flexibility, simplicity, and sensitivity, the TFC and its multiple-channel extension can play a significant role in the next generation of remote-sensing instruments.

This study focuses on the applications of remote sensing techniques and digital analysis to characterizing of tectonic features of the Rincon Mountains metamorphic core complex. Data included Landsat Thematic Mapper (TM) images, digital elevation models (DEM), and digital orthophoto quadrangle quads (DOQQ). The main findings in this study are two nearly orthogonal systems of structures that have never been reported in the Rincon Mountains. The first system, a penetrative faulting system of the footwall rocks, trends N10-30°W. Similar structures identified in other metamorphic core complexes. The second system trends N60-70°E, and has only been alluded indirectly in the literature of metamorphic core complexes. The structures pervade mylonites in Tanque Verde Mountain, Mica Mountain, and the Rincon Peak area. As measured on the imagery, spacing between the N10-30°W lineaments ranges from ∼0.5 to 2 km, and from 0.25 to 1 km for the N60-70°E system. Field inspection reveals that the N10-30°W trending system, are high-angle normal faults dipping mainly to the west. One of the main faults, named here the Cabeza de Vaca fault, has a polished, planar, striated and grooved surface with slickenlines indicating pure normal dip-slip movement (N10°W, 83°SW; slickensides rake 85°SW). The Cabeza de Vaca fault is the eastern boundary of a 2 km-wide graben, with displacement as great as 400 meters. The N10-30°W faults are syn- to post-mylonitic, high-angle normal faults that formed during isostatic uplift of the Rincon core complex during mid-Tertiary time. This interpretation is based on previous works, which report similar fault patterns in other metamorphic core complexes. Faults trending N20-30°W, shape the east flank of Mica Mountain. These faults, on the back dipping mylonitic zone, dip east and may represent late-stage antithetic shear zones. The Cabeza de Vaca fault and the back dipping antithetic faults accommodate as much as 65% of the extension due to doming of the core complex. The N60-70°E structures, not verified as a fault system, are a joint system pervading the footwall rocks of the metamorphic core complex. This system is less systematic. Spacing varies from 0.25 to 1 km. Both systems control the drainage of the mountains.

A radiative transfer model for a homogeneous plane parallel vegetative canopy is developed. A method to decompose and calculate the uncollided, once scattered, and multiply scattered radiation components is also presented based on the turbid medium approach. The new model accounts for the some effects exhibited only by homogenous vegetation canopies. This allows the simulation of the scattering processes within the plant canopy as a function of the traditional canopy architecture parameters such as leaf area index (LAI), leaf reflectance and transmittance, and also the canopy height and leaf size, stem etc... This model integrates two different approaches: the turbid medium approach and an approach that takes into account the finite size of the leaves. Furthermore, a state of the art leaf radiation transfer model (PROSPECT) is incorporated into the new model that provides leaf scattering properties as inputs (transmittance and reflectance vs. wavelength). Based on the proposed canopy model, a computer code in MATLAB was formulated using the discrete ordinates numerical method. This was used to calculate the bi-directional reflectance factor for a given geometry and a viewing angle from a plant canopy. The code for the new model is modular and very simple to use. The new model has been validated against other radiative transfer models, and compared with measured data. The results obtained using the model are in good agreement with the measured data.

The investigations contained in this body of work detail a viable proof-of-concept model for monitoring seasonal snow pack propensity for melt release based on time-variant snow surface optical and thermal properties. The model has been called the Near Surface Moisture Index- (Snow) (NSMI). The NSMI was developed based on time-variant snow surface optical and thermal properties. This research achieved three primary objectives: 1).development of theoretical foundation and surface moisture sensitive algorithm used to track both surface melt and pack discharge potential; 2.) time-dependent phases of coupling and decoupling between snow surface properties and melt discharge were characterized through analysis of long-term surface and sub-surface state variables; 3.) and sensitivity of optical satellite systems specifically, EOS TERRA-MODIS, to melting were was examined through radiative transfer simulations. Simulated at-sensor radiance was produced for various grain size changes to determine MODIS capacity to track melt onset. MODIS wavelengths greater than 667nm were sensitive to large changes in grain sizes, particularly bands with coarse spatial resolution (1000m). Longer wavelengths showed greater sensitivity to small changes in smaller grains than to small changes in larger grains. Shorter wavelengths at 500m spatial resolution appeared less effective overall for monitoring changes in grain size. NMSI feature space using Normalized Difference Snow Index (NDSI) on the abscissa and brightness temperature (Tb) on the ordinate was simulated. Simulated NDSI as a function of grain radius saturated approximately around 400-450 &amp;#956;m. ASTER derived NSMI demonstrated behavior consistent with simulations with deviations due to topography, vegetation, and regional heterogeneity. We examined NSMI performance during an entire melt season through tracking phases of coupling between snow surface properties and propensity for melt using two ground-base approaches; one with higher snow surface spectral information and low temporal resolution, the other with high temporal resolution and coarse spectral information. Phases of decoupling exhibited within ground-based time varying simulated NSMI were regulated by the temporal resolution specified to construct the feature space. Coarser temporal intervals on surface optical/thermal variables correlated the NSMI feature space various components of surface radiative variability. Coarser temporal optical and thermal resolution will tend to reduce variability within the NSMI feature space due to specific snowfall events.

Improved knowledge of landscape seasonal variations and phenology at the regional scale is needed for carbon and water flux studies, and biogeochemical, hydrological, and climate models. Amazon vegetation mechanisms and dynamics controlling biosphere-atmosphere interactions are not entirely understood. To better understand these processes, vegetation photosynthetic activity and canopy water and temperature dynamics were analyzed over various types of vegetation in Amazon using satellite data from the Terra-Moderate Resolution Imaging Spectroradiometer (MODIS). The objectives of this dissertation were to 1) assess the spatial and temporal variations of satellite data over the Amazon as a function of vegetation physiognomies for monitoring and discrimination, 2) investigate seasonal vegetation photosynthetic activity and phenology across the forest-cerrado ecotone and conversion areas, and 3) investigate seasonal variations of satellite-based canopy water and land surface temperature in relation to photosynthetic activity over the Amazon basin.The results of this study showed the highly diverse and complex cerrado biome and associated cerrado conversions could be monitored and analyzed with MODIS vegetation index (VI) time series data. The MODIS enhanced vegetation index (EVI) seasonal profiles were found useful in characterizing the spatial and temporal variability in landscape phenology across a climatic gradient of rainfall and sunlight conditions through the rainforest-cerrado ecotone. Significant trends in landscape phenology were observed across the different biomes with strong seasonal shifts resulting from differences in vegetation physiognomic responses to rainfall and sunlight. We also found unique seasonal and temporal patterns of the land surface water index (LSWI) and land surface temperature (LST), which in combination with the EVI provided improved information for monitoring the seasonal ecosystem dynamics of the Amazon rainforest, cerrado, ecotone, and conversion areas. In conclusion, satellite-based, regional scale studies were found to aid in understanding land surface processes and mechanisms at the ecosystem level, providing a "big picture" of landscape dynamics. Coupling this with ground, in-situ measurements, such as from flux towers, can greatly improve the estimation of carbon and water fluxes, and our understanding of the biogeochemistry and climate in very dynamic and changing landscapes.

<p> Ultra-spectrometers with a spectral resolution better than 1 cm_-1, such as AIRS on the AQUA, IASI on the Metop-A/B, and CrIS on the Suomi-NPP, have become operational during the past decade. The radiance spectra measured by these satellite-borne spectrometers provide soundings of the atmosphere with relatively high vertical resolution and high accuracy except for the lower atmosphere. Meanwhile, many ground-based ultra-spectrometers based on the Michelson Interferometer have been incorporated into the Department of Energy Atmospheric Radiation Measurement facilities and aboard NOAA research vessels. These instruments provide temperature and water vapor soundings within the planetary boundary layer continuously with very high vertical resolution. This dissertation develops a retrieval procedure which can combine the radiance measured by ground-based spectrometers and coincident observation from satellite-borne instruments to improve retrieval results throughout the lower atmosphere. </p><p> To verify the feasibility and improved accuracy of the combined retrieval, 90 clear sky cases from four in-situ radiosonde measurement locations or geographical regions, were selected for this study. Each region consists of radiosonde measurements of temperature and water vapor, downwelling radiance spectra measured at approximately the balloon launch time, and upwelling radiance observation by IASI at the location and time coincident with the surface radiance and radiosonde measurements. </p><p> These cases indicate, that when compared with the retrieval from upwelling radiance or downwelling radiance spectra only, there is a significant improvement of the retrieval using combined upwelling and downwelling radiance spectra is observed. At altitude below the 800 hPa pressure level, the errors using the combined retrieval are about 0.5 &ndash; 1 K in temperature, and 20 &ndash; 40 % for water vapor mixing ratio. These errors are approximately one-third the magnitude of errors for the sounding retrieval obtained using satellite upwelling radiance alone.</p>