Indiana University-Purdue University Indianapolis (IUPUI) / Phytoplankton size classes (pico-plankton, nano-plankton, and micro-plankton) provide information about pelagic ocean ecosystem structure, and their spatiotemporal variation is crucial in understanding ocean ecosystem structure and global carbon cycling. Remote sensing provides an efficient approach to estimate phytoplankton size compositions on global scale. In the first part of this thesis, a global sensitivity analysis method was used to determine factors mainly controlling the variations of remote sensing reflectance and inherent optical properties inverse algorithms. To achieve these purposes, average mass-specific coefficients of particles were first calculated through Mie theory, using particle size distributions and refractive indices as input; and then a synthesis remote sensing reflectance dataset was created using Hydrolight. Based on sensitivity analysis results, an algorithm for estimating phytoplankton size composition was proposed in the second part. This algorithm uses five types of spectral features: original and normalized remote sensing reflectance, two-band ratios, continuum removed spectra, and spectral curvatures. With the spectral features, phytoplankton size compositions were regressed using support vector machine. According to validation results, this algorithm performs well with simulated and satellite Sea-viewing Wide Field-of-view Sensor (SeaWiFS) and Moderate Resolution Imaging Spectroradiometer (MODIS), indicating that it is possible to estimate phytoplankton size compositions through satellite data on global scale.

On April 9, 1940, Germany invaded Denmark. Instantly, the fate and status of Greenland, a Danish colony, was thrust into limbo. During the war, Greenland’s vital mineral resources and location made it significant for the warring parties on both sides of the Atlantic. However, conflicting international corporate and political interests made any act to defend the island on the part of the Allies, or the officially neutral Americans, problematic. Within a year of the Danish occupation, the American government had signed an agreement for the defense of Greenland, extending the protection of both the Monroe Doctrine and the American military to the island. This action was an important step in the formal expansion of American influence in the Western Hemisphere that occurred during the Second World War. This thesis argues that global economic, political, and technological changes led to Greenland’s increased geopolitical significance and set the stage for a shift in the balance of power within the North Atlantic Triangle. It demonstrates how decisions relating to the security of the island came to be made and how conflicting interests within and between governments affected the genesis of the occupation. It explores how Winston Churchill’s decision to mine the North Sea led to the American occupation of Greenland and examines the ways in which the effects of Churchill’s actions raised concerns in Canada about the possibility of a British defeat, which in turn led Mackenzie King, the Canadian Prime Minister, to align his foreign policy closer to that of the United States’ President Roosevelt. This thesis also asserts that Roosevelt successfully used the potential foreign occupation of Greenland to demonstrate to the American public the dangers of foreign conflicts to the United States and to further his hemispheric security objectives both domestically and abroad. These events had a profound and lasting impact on the relationships within the North Atlantic Triangle and on political identity in Greenland, and signalled an important shift in the foreign policy of the United States toward greater American involvement in world affairs.