Volume 5 (2009) Pages 21-24
Horizontal wind at 700 hPa over Sumatra (0°N, 100°E) analyzed by National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis was compared with wind observed by a VHF wind-profiling Doppler radar at Kototabang (0.20°S, 100.32°E) during 2001-2007. Radiosonde wind data at Padang (0.88°S, 100.35°E) were reported through Global Telecommunication System (GTS) for assimilation into NCEP/NCAR reanalysis. To examine if radiosonde observations at Padang improve wind quality of NCEP/NCAR reanalysis over Sumatra, dataset of radar wind, which was compared with NCEP/NCAR reanalysis, was divided into the group when radiosonde observations were reported though GTS (Group A) and when they were not reported (Group B). For each group, correlation coefficient and regression line were computed. In Group A, both zonal and meridional winds showed better correlation coefficients (0.90 and 0.77) than in Group B (0.79 and 0.63). Amplitude of NCEP/NCAR-reanalysis zonal and meridional winds showed a better agreement in Group A (82 and 96% of radar wind) than in Group B (66 and 80% of radar wind). These results suggest that wind observations in the Indonesian Maritime Continent contribute to improve wind quality of NCEP/NCAR reanalysis there.