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
  
• Pacific Wind stress  A1.2
  
• Surface Currents (a)  A1.3
  
• Surface Currents (b)  A1.4
  
  

Tropical Pacific Drifting Buoys

Rick Lumpkin / Mayra Pazos, AOML, Miami

DECEMBER 2011

During December 2011, 317 satellite-tracked surface drifting buoys, 51% with subsurface drogues attached for measuring mixed layer currents, were reporting from the tropical Pacific. Across the basin, drifters in the South Equatorial Current measured westward anomalies of O(10-20 cm/s) between the equator and 20S. Between 180-160E, these anomalies extended to 8N. Many drifters north of 10N and west of 170W measured SSTs warmer than normal by 0.5-3.0C, while drifters to the south and east measured SSTs at or slightly cooler (0-1.5C) than climatological December values. Cold anomalies were most prevalent between 20S to 20N, east 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 1993-2010 (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.