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

MAY 2009

During May 2009, 359 satellite-tracked surface drifting buoys, 70% with subsurface drogues attached for measuring mixed layer currents, were reporting from the tropical Pacific. Four drifters at 150-160W, 3-6N, exhibited strong (30-60 cm/s) eastward anomalies; elsewhere, the major currents exhibited weak (0-10 cm/s) westward anomalies compared to May climatology. Most drifters away from the northwest part of the basin measured SST at or above normal May values, with anomalies of 0 to +1.5C. Warm anomalies were especially prevalent in the southeast tropical Pacific. Cold anomalies (-0.5C to -3.0C) were measured by many drifters in the northwest, north of 20N and west of 170W. These SST anomaly patterns have persisted over the previous several months.

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.