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

JULY 2007

During July 2007, 338 satellite-tracked surface drifting buoys, 70% with subsurface drogues attached for measuring mixed layer currents, were reporting from the tropical Pacific. Strong (>50 cm/s) westward anomalies were measured by five drifters at 6-8N, 160W to the dateline, perhaps associated with advection in the tropical instability wave train; these anomalies dominate the current anomaly map in this region. Elsewhere, 10-20 cm/s westward anomalies were measured across most of the tropical Pacific basin, as was seen in June. As in May through June, most drifters north of the equator and east of the dateline measured SSTs near normal seasonal values. Anomalously cold (-0.5 to -1.5C) water was measured by the drifters between 135-160W in the instability wave band. South of the equator and west of 110W, the majority of drifters measured SSTs of +0.5 to +1.5C above typical July values, a pattern similar to that seen in June.

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.