The problem of creating synoptic maps from asynoptically gathered data has prompted the development of a number of schemes. Most notable among these schemes are the Kalman filter, the Salby-Fourier technique, and constituent reconstruction. This thesis presents a new technique, called trajectory mapping. Trajectory mapping employs a simple model of air parcel motion to create synoptic maps from asynoptically gathered data. To assess the applicability of the technique, four sources of trajectory mapping errors were analyzed. The analysis revealed that (1) the computational error is negligible; (2) measurement uncertainties can result in errors which grow with time scales on the order of a week; (3) isentropic approximations lead to errors characterized by time scales of a week; and (4) wind field inaccuracies can cause significant errors in individual parcel trajectories in a matter of hours. All the studies, however, indicated that while individual trajectory errors can grow rapidly, constituent distributions, such as those depicted in trajectory maps, are much more robust, maintaining a high level of accuracy for periods on the order of several weeks. The trajectory mapping technique has been successfully applied to a variety of problems. First, trajectory mapping was employed in the study of dynamical wave-breaking events. Second, trajectory mapping was applied in satellite data validation studies, both for the determination of instrument accuracy and precision. Third, trajectory mapping was used to assess the accuracy of the meteorological wind fields. Such demonstrations imply that trajectory mapping will become an important tool in answering questions of global change, particularly the issue of ozone depletion.

We interpret satellite, aircraft, and ground-based measurements using the GEOS-Chem Chemical Transport Model (CTM) to better understand the global transport and distribution of fine aerosol (PM2.5). Using satellite retrievals of Aerosol Optical Depth (AOD) from the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Multiangle Imaging Spectroradiometer (MISR), we estimate an annual growth in Chinese sulfur emissions of 6.2-9.6% between 2000-2006, in agreement with bottom-up inventories. Using aircraft measurements from the Intercontinental Chemical Transport Experiment (INTEX-B) with a CTM, we calculate that 56% of measured sulfate between 500-900 hPa over British Columbia is due to East Asian sources. We find evidence of a 72-85% increase in the relative contribution of East Asian sulfate to the total burden in spring off the northwest coast of the United States since 1985. We interpret retrievals AOD from MODIS and MISR using GEOS-Chem to estimate global long-term (2001-2006) mean PM2.5 concentrations at a resolution of 0.1° x 0.1°. Evaluation of the satellite-derived estimate with ground-based in-situ measurements indicates significant spatial agreement with North American measurements (r = 0.77, slope = 1.07, n = 1057) and with non-coincident measurements elsewhere (r = 0.83, slope = 0.86, n = 244). The one standard deviation uncertainty in the satellite-derived PM2.5 is 25%, inferred from the AOD retrieval and aerosol vertical profiles errors and sampling. The global population-weighted mean uncertainty is 6.7 µg/m3. We find a global population-weighted geometric mean PM2.5 concentration of 20 ?g/m3. The World Health Organization Air Quality PM2.5 Interim Target-1 (35 µg/m3 annual average) is exceeded over central and eastern Asia for 38% and 50% of the population, respectively. Annual mean PM2.5 concentrations exceed 80 µg/m3 over Eastern China. We test the capability of remotely-sensed PM2.5 to capture extreme short-term events by examining the major biomass burning event around Moscow in summer 2010. We find good agreement (r2=0.85, slope=1.06) between daily estimates of PM2.5 from in-situ and satellite-derived sources in the Moscow region during the fires. Both satellite-derived and in-situ values have peak daily mean concentrations of approximately 600 ?g/m3 on August 7, 2010 in the Moscow region.

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No description available.

In an effort to attain a quantitative understanding of the temporal and spatial variability of the tropical radiation budgets and the cloud-radiative forcing, a complete annual cycle of measurements by the Earth Radiation Budget Satellite scanning radiometer is analyzed. / Results show the existence of strong diurnal variation in the longwave emission over land and desert scenes and in the reflected shortwave radiation for all scenes. A bias in the Earth Radiation Budget Experiment scene identification algorithm against clear tropical scenes at night is evident in the longwave diurnal variation results. Substantial east-west variation is exhibited in the radiation and the cloud forcing components for some latitude zones. The largest seasonal changes in the radiation and the cloud forcing components are associated with the Asian summer monsoon and the migration of the Intertropical Convergence Zone. Cloud forcing results show a strong dependence of net forcing on cloud type, with small values for convective clouds and large negative values for stratiform clouds.

With the development of Geographical Information System (GIS) and remote sensing techniques, a great deal of data has provided a set of continuous samples of the earth surface from local, regional to global scales. Several multi-scale, multi-resolution, pyramid or hierarchical methods and statistical methods have been developed and used to investigate the scaling property of remotely sensed data: local variance, texture method, scale variance, semivariogram, and fractal analysis. This research introduces the wavelet transform into the realm of scale study in remote sensing and answers three research questions. Three specific objectives corresponding to the three research questions are answered. They include: (1) exploration of wavelets for scale-dependent analysis of remotely sensed imagery; (2) examination of the relationships between wavelet coefficients and classification accuracy for different resolutions and their improvement of classification accuracy; and (3) multiscaling analysis and stochastic down-scaling of an image by using the wavelet transform and multifractals. The significant results obtained are: (1) Haar wavelets can be used to investigate the scale-dependent and spatial structure of an image and provides another method for selection of optimal sampling size; (2) there is a good relationship between classification accuracy and wavelet coefficients. High/low wavelet coefficient reflects low/high classification accuracy in each land cover type. (3) the maximum likelihood classifier with inclusion of wavelet coefficients can improve land cover classification accuracies. (4) the moment-scale analysis of wavelet coefficients can be used to investigate the multifractal properties of an image. Also the stochastic down-scaling model developed based on wavelet and multifractal generates good simulation results of the fine resolution image.

<p> This dissertation describes an active/passive imager (API) that provides reliable, nighttime, target acquisition in a man-portable package with effective visual range of about 4 kilometers. The reflective imagery is easier to interpret than currently used thermal imagery. Also, in the active mode, the API provides performance equivalent to the big-aperture, thermal systems used on weapons platforms like tanks and attack helicopters. This dissertation describes the research needed to demonstrate both the feasibility and utility of the API. </p><p> Part of the research describes implementation of a silicon focal plane array (SFPA) capable of both active and passive imaging. The passive imaging mode exceeds the nighttime performance of currently fielded, man-portable sensors. Further, when scene illumination is insufficient for passive imaging, the low dark current of SFPA makes it possible to use continuous wave laser diodes (CWLD) to add an active imaging mode. CWLD have advantages of size, efficiency, and improved eye safety when compared to high peak-power diodes. Because of the improved eye safety, the API provides user-demanded features like video output and extended range gates in the active as well as passive imaging modes. </p><p> Like any other night vision device, the API depends on natural illumination of the scene for passive operation. Although it has been known for decades that "starlight" illumination is actually from diffuse airglow emissions, the research described in this dissertation provides the first estimates of the global and temporal variation of ground illumination due to airglow. </p><p> A third related element of the current research establishes the impact of atmospheric aerosols on API performance. We know from day experience that atmospheric scattering of sunlight into the imager line-of-sight can blind the imager and drastically degrade performance. Atmospheric scattering of sunlight is extensively covered in the literature. However, previous literature did not cover the impact of atmospheric scattering when the target is diffusely illuminated by airglow.</p>

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No description available.

Three-dimensional radar data for three Florida storms are used with a radiative transfer model to simulate observations at 19 GHz by a nadir pointing, satellite bourne microwave radiometer. Estimates were made of spatial sampling errors due to both horizontal and vertical variability of the precipitation. Calibrated radar data were taken as realistic representations of rainfall fields. / The optimal conversion between microwave brightness temperature and rainfall rate was highly sensitive to the spatial resolution of observations. Retrievals were made from the simulated microwave measurements using rainfall retrieval functions optimized for each resolution and for each storm case. / There is potential for microwave radiometer measurements from the planned TRMM satellite to provide better 'snapshot' estimates than area-threshold VIS/IR methods. Variability of the vertical profile of precipitation did not seriously reduce accuracy. However, it is crucial that calibration of retrieval methods be done with ground truth of the same spatial resolution.