Extended Abstract (324K)JP5.12
Wind climate analyses for a 61-m tower in the Southeast
Allen H. Weber, Savannah River Technology Center, Aiken, SC; and R. L. Buckley and R. J. Kurzeja
The Savannah River Technology Center’s (SRTC) Atmospheric Technologies Group (ATG) has operated the 61-meter Central Climatology (CC) tower near the center of the Savannah River Site (SRS) since 1985. The tower is instrumented at 4, 18, 36, and 61-meter levels with wind, temperature, and dew-point sensors. This presentation will focus on ten years of CC’s quality assured wind data to depict changes in the wind speed, direction, and variability frequency distributions with height, time-of-day, two-week period and year. Our study will also show how the CC tower data relates to nearby National Weather Service 10-m towers.
Terrain steering of the wind from the Appalachian Mountains is suggested in the seasonal and diurnal patterns of the wind. The CC Tower is strongly influenced by sea breezes in the evening hours (mainly in the spring and summer seasons) that penetrate from the Atlantic coast up the Savannah River channel. In autumn all levels of the CC Tower are subject to northeasterly winds that arise from high-pressure systems to the north and northwest.
The mean wind speeds for the ten-year period were determined by hour, two-week period and year. The highest mean wind speed was seen at night at the top tower level. The lowest mean wind speed was found during the night at the lowest tower level. The mean wind speeds for twenty-six two-week periods showed that the highest wind speeds are achieved during late February-early March at the 61-m tower level. The lowest wind speeds are found during mid-August at the 4-m tower level.
Subjective comparisons between the annual wind roses for Columbia, South Carolina (CAE) (~100 kilometers northeastward) and Augusta, Georgia (AGS) (~40 kilometers westward) with the CC tower showed that the top three tower levels resembled CAE whereas the bottom level resembled AGS. On shorter time scales, subjective comparisons show that the CC tower roses have similarities to both AGS and CAE’s roses. Neither AGS nor CAE were consistently similar to the lower two CC levels for shorter (two-week) time scales.
The relationship between the North Atlantic Oscillation (NAO) index or El Niño/La Niña conditions and CC winds was explored by categorizing the indices for NAO and El Niño/La Niña into three subsets for each. Statistical correlation between CC’s 61-m wind speed and El Niño/La Niña conditions was very low in each subset. A similar result was found for the statistical correlation between the NAO index and CC winds.
Supplementary URL: http://www.srs.gov/weathercenter/winds/C_C_winds.pdf
Joint Poster Session 5, Climate Variability (JOINT with THE 15TH SYMPOSIUM ON GLOBAL CHANGE AND CLIMATE VARIATIONS AND THE 14TH CONFERENCE ON APPLIED CLIMATOLOGY; Hall 4AB)
Wednesday, 14 January 2004, 2:30 PM-4:00 PM, Hall 4AB
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