POSITION - GEOGRAPHIC collected from CARTHE surface drifter in South Atlantic Ocean from 20230306 to 20230727 (NCEI Accession 0301712).

We deployed 200 CARTHE surface drifters drogued at 0.60 m depth. Our goal was to sample 4 dynamical regimes and measure the associated surface dispersion across multiple scales (500 m to 500 km, minutes to months)

The sampling rate was set to every 10 minutes, giving theoretical battery life expectancy of more than 3 months. The GPS signal was very good despite constant difficult weather (winds and waves).

The deployments followed a radiator pattern consisting of 4 12km-long lines aligned with the wind and separated by 3.5 km. We dropped 4 nodes of 3 drifters per line, separated by 0.5km, 1 km, and 2 km. This set up was chosen to provide synoptic and isotropic sampling of the submesoscale range and minimize the deployment time from a single ship. It took 3 to 4 hours at full speed (8 to 12 knots) to complete a deployment depending on conditions. The location for each deployment was determined based on analysis of the most recent SSH and SST fields available, as well as shipboard ADCP plots, TSG transects, and weather forecasts (ECMWF).

The package contains the trajectories of CARTHE surface drifters that were released in the Cape Basin (South Atlantic) in March 2023. 
There are 4 ASCII files: 
quicche_spot_xml_data.dat: the raw data ; 
quicche_spot_xml_data_qc1.dat: QC1 = the raw data including pre-deployment GPS tests in Miami flagged; 
quicche_spot_xml_data_qc2.dat: QC2 = bad records removed; 
quicche_spot_xml_data_qc3.dat: QC3 = QC2 interpolated on a regular 30 minutes time grid. 
Each file has 9 or 10 columns described here: 
Column 1: manufacturer message id
Column 2: manufacturer GPS id
Column 3: drifter id
Column 4: time in YYYY-MM-DDTHH:mm:ss.SSSZ format
Column 5: manufacturer time in seconds, unknown zero
Column 6: latitude in decimal degrees North
Column 7: longitude in decimal degrees East
Column 8: GPS record setting
Column 9: battery state GOOD or LOW
Column 10: if PRE it indicates the GPS was being tested pre-deployment. if nothing, then the GPS is in the drifter and deployed. 

Only Columns 3,4,6, and 7, are needed to define the trajectories of the drifters. 
QC2 and QC3 files are useful to most users, other files are provided for completeness.

Here is an example: 
1865211416	0-4435604	Q1_0001	2022-11-03T17:35:11.000Z	1667496911	25.73166	-80.1633	UNLIMITED-TRACK	GOOD	PRE 
The third column has the drifter ID (Q1_0001). The fourth column has the time in YYYY-MM-DDTHH:mm:ss.SSSZ format. The sixth column is 25.73166 N, the latitude in decimal degrees. The seventh column is -80.1633 E, the longitude in decimal degrees. All other columns are ID of the messages, or the GPS, or the battery state, or the predeployment status. These are not useful to most users.
QC2 and QC3 files are useful to most users, other files are provided for completeness.