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 2007

During December 2007, 310 satellite-tracked surface drifting buoys, 80% with subsurface drogues attached for measuring mixed layer currents, were reporting from the tropical Pacific. Strong current anomalies were associated with well-developed instability waves, particularly at 5N, 130-140W. Elsewhere, currents exhibited uniformly westward anomalies (stronger NEC, SEC; weaker NECC). These anomalies were ~10 cm/s across the basin. Cold anomalies of -0.5 to -1.5 C were measured by most drifters east of 130W and south of the equator, a persistent anomaly for the last three months, with larger anomalies of -1.5C to -3.0C common east of 100W. Comparable cold anomalies were seen in the northern TIW train, associated with advection of upwelled equatorial water. Also seen since October, warm anomalies were common west of the dateline.

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.