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

MARCH 2008

During March 2008, 307 satellite-tracked surface drifting buoys, 77% with subsurface drogues attached for measuring mixed layer currents, were reporting from the tropical Pacific. As seen last month, westward anomalies were observed throughout most of the tropical Pacific basin, except in the region 0-8N, 120-140W. A number of drifters in this region exhibited strong eastward anomalies, but were close together and may have been advected by a single feature (e.g., a tropical instability wave) rather than reflecting a larger-scale anomaly. Large scale westward anomalies along 10N were 20 cm/s, as seen for many months now, and were 0-10 cm/s south of the equator. Cold SST anomalies (-0.5 to -3.0C) persisted across the basin between 12S and 15N, while most drifters south of 20S measured SST warmer than normal March values by +0.5 to +1.5C. Several drifters between 95W and the South American coast measured SST warmer by +1.5 to +3.0C.

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.