Long Range Forecast Possibilities for X-Band Radar Construction on Shemya

摘要

The Missile Defense Agency (MDA) plans to construct, during a two- week period, an X-Band Radar (XBR) on Shemya, AK. Wind speeds must not, at any time during the construction, exceed a 25 knot limit set by the MDA for lifting the massive dome panels into place. The goal of this research was to explore the possibilities of long-range forecasts to determine the feasibility of predicting any upcoming two-week windows of opportunity, well in advance, that will ensure the successful completion of constructing the XBR on Shemya. In order to reach this goal, the following objectives were achieved; (1) a climatological wind study for Shemya to assess the optimal climatological window to build the XBR, (2) a detailed synoptic study over the North Pacific, to gain an understanding of how synoptic weather systems develop, move, and vary on an annual basis, (3) a traditional statistical analysis of the data followed by a Classification and Regression Tree (CART) analysis for pattern recognition of global teleconnection indices, and (4) develop forecasting decision trees to assist the 11th Operational Weather Squadron (OWS) Alaskan forecast hub in this daunting task. The Aleutian Island chain is plagued by persistent strong winds, since the Aleutian Low and expanding polar vortex affect the region in the winter, as do tropical storms and frontal passages in the summer. This, combined with Shemya being located near the exit region of the climatological storm track off the East Asian continent, makes the island one of the most challenging forecast locations in the Northern Hemisphere. This study compares surface winds and teleconnection indices, as computed by the Climate Prediction Center (CPC), to statistically analyze the data. The data were analyzed using standard statistical regression techniques, including linear and multiple linear regression methods, and then CART analysis was used for large-scale pattern recognition.