Monday, 14 January 2002
DAILY CYCLES OF LOW LEVEL WINDS OVER THE ISLAND OF NAURU IN THE EQUATORIAL WESTERN PACIFIC
Identifying any island-induced effect on winds over Nauru is necessary for better interpreting wind measurements taken by a wind profiling radar at this island. The objectives of this research were to identify any sea breeze (island-induced phenomenon) over the wind profiler site at Nauru as well as to determine its interannual variability. Measurements were made from a few hundred meters to about 2-kilometers altitude using a wind profiler developed by the NOAA Aeronomy Lab. Half-hourly vertical profiles of winds from 1994 to 1999 were studied. Average daily cycles and their anomalies were computed for several single-year and 3-month periods. These were analyzed for the presence of onshore flow of winds and its variability throughout the years. No onshore flow was observed for the years of 1994-1999 over the southern region of the island. Southerly anomalies were found between 10:30 and 14:30 Local Time below 600 meters for the years of 1995, 1996, 1998 and 1999. The 24-hour cycle of the meridional wind was examined through harmonic analysis and its maximum positive signal was at 11:12 LT for the annual averages of 1994-1999. Southerly anomalies were observed depending on the region's sea surface temperature and/or the Southern Oscillation status.