Application of collected data
Presentations at the DBCP Technical Workshop
Chennai, India, 18-19 October 2004


Theme 2: Operations

Lifetime Statistics of Most Recent Drifter Developments
Rick Lumpkin, Mayra Pazos (NOAA) 

ABSTRACT:

A total of 4076 buoys were deployed from 1998 to 2003, that is an average of 680 drifters per year by all National and International participants, of which 73% belonged to the Global Drifter Center (GDC). The failure rate on deployment for years 1998 and 1999 was 11%, improving to 5% for years 2000-2002 and to 3% in year 2003.

During 2000-2003 drifters 'died' for the following reasons: 63% due to the transmitter failure, 22% by drifters running aground, 14% by being picked up by vessels or fishermen in the area and 1% due to miscellaneous reasons, like low battery voltage, etc.

We also examined the half-life (amount of time after deployment half the buoys are still alive/drogued) as a function of year, for transmitter, drogue and SST sensor. During 19998-2003, there was a steady improvement in the transmitter lifetime, and a tremendous increase in the lifetime of drogues and SST sensors. These statistics will also be presented for different sub-regions of the world (tropical basins, Southern Ocean, etc.)