Tropical Highlights

  Table of Atmospheric Indices  (Table 1)

  Table of Oceanic Indices  (Table 2)

  Time Series

  Time-Longitude Sections

  Mean & Anomaly Fields

  Appendix 1: Outside Contributions

• Tropical Drifting Buoys  A1.1
  
• Thermistor Chain Data  A1.2
  
• TAO/TRITON Array (a)  A1.3
  
• TAO/TRITON Array (b)  A1.4
  
• East Pac. SST & Sea Level  A1.5
  
• Pacific Wind stress  A1.6
  
• Surface Currents (a)  A1.7
  
• Surface Currents (b)  A1.8
  
  

Tropical Pacific Drifting Buoys

Rick Lumpkin / Mayra Pazos, AOML, Miami

DECEMBER 2009

During December 2009, 407 satellite-tracked surface drifting buoys, 76% with subsurface drogues attached for measuring mixed layer currents, were reporting from the tropical Pacific. Dramatic eastward anomalies of 50-70 cm/s were measured by many equatorial drifters in the central part of the basin, with anomalies as high as 80cm/s in the longitude band 160W to the dateline. This El Nino pattern was associated with hot equatorial SST anomalies of +1.5 to +3.0C from 130W to 180. Outside of the equatorial band, and west of about 110W, most drifters measured warm (+0.5 to +1.5C) SST anomalies. Slightly cold SST anomalies (-0.5 to -1.5C) were observed in the southeasternmost corner of the domain as in the previous month.

FIGURE A1.1 a) Top: Movements of drifting buoys in the tropical Pacific Ocean. The linear segments of each trajectory represent a one week displacement. Trajectories of buoys which have lost their subsurface drogues are gray; those with drogues are blue. b) Middle: Monthly mean currents calculated from all buoys 1993-2002 (gray), and currents measured by the drogued buoys this month (black) smoothed by an optimal filter. c) Bottom: Anomalies from the climatological monthly mean currents for this month.