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

SEPTEMBER 2011

During September 2011, 354 satellite-tracked surface drifting buoys, 49% with subssurface drogues attached for measuring mixed layer currents, were reporting from the tropical Pacific. Few drifters measured near-equatorial currents in the western half of the basin. Very strong northward anomalies measured by three near-equatorial drifters at 129W are likely associated with a tropical instability wave. Between 110W and the date line, strong equatorial westward anomalies of O(50 cm/s) were measured by a number of drifters between the equator and 5S. Most drifters between 10N and 10S measured SSTs cooler by 0.5 to 1.5C than the the climatological September value.

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.