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

APRIL 2011

During April 2011, 415 satellite-tracked surface drifting buoys, 61% with subsurface drogues attached for measuring mixed layer currents, were reporting from the tropical Pacific. As seen since September 2010, the westward SEC was stronger than normal, with westward anomalies of O(10 cm/s) present in a broad latitude range from 5-20S. Between 10-20N, the westward NEC was also faster than average by ~5 cm/s. Cold SST anomalies of -0.5 to -1.5C were measured by many drifters east of 160W from 20S to 20N, a pattern seen since February.

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.