TITLE: VOCALS_RHB_UW_Chlorophyll

AUTHOR(S):

Andrew J. Hind 	ajhind@googlmail.com
Patricia A. Matrai	pmatrai@bigelow.org

Bigelow Laboratory for Ocean Sciences
180 McKown Point
W. Boothbay Harbor, ME 04575 USA
Phone 207 633 9600; Fax  207 633 9641

1.0 DATA SET OVERVIEW:
Surface seawater chlorophyll concentrations estimated from fluorescence. Data was collected during Legs 1 and 2 of the VOCALS cruise

Time period covered by the data: Leg 1 data is from 21-Oct-2008 to 2-Nov-2008 and leg 2 is from 10-Nov-2008 until 01-Dec-2008.

Platform: Ronald H. Brown

Location: mobile

2.0 INSTRUMENT DESCRIPTION:

Chlorophyll fluorescence was measured continuously in water taken from the ship’s non-toxic supply (intake at 5 meters) using a 10AU fluorometer fitted with a flow through cell (Turner Designs, Sunnyvale, CA). Discrete samples were taken in triplicate at least twice daily and used to calibrate the continuous instrument. The samples were filtered onto 25mm filters (GF/F, Whatman Ltd., Kent, UK) and immediately frozen at ?20 C for subsequent analysis according to Holm-Hansen et al. (1965). These were measured with a second 10AU fluorometer fitted with a discrete sample cell and calibrated using pure chlorophyll a (Sigma Biochemicals).

3.0 DATA COLLECTION AND PROCESSING:

The calibration determined was 

Estimated chlorophyll = (Fluorescence -1.349)/3.1019. The r2 of the relationship was 1.0. The detection limit is estimated to be 0.15 micrograms chlorophyll per liter.

4.0 DATA FORMAT:

Column delimited ASCII

Headers
Year	Month	Day	HH	MM	SS	Cruise Leg	Latitude		Longitude		Chl
UTC	UTC	UTC	UTC	UTC	UTC			"Degrees N, digital"	"Degrees E, digital"	Microgram/liter

Chlorophyll, sampling frequency approx. every 90 seconds, range 0.0-9.2 micrograms chlorophyll per liter.

Date of data version: 31-Aug-2010 

5.0 DATA REMARKS:

REMARKS = This data can be considered final
REMARKS = Data point Date/Time provided in UTC
REMARKS = Missing data = NaN

6.0 REFERENCES:

Holm-Hansen, O., Lorenzen, C., Holmes, R., and Strickland, J.: Fluorometric determination of chlorophyll, ICES J. Mar. Sci., 30, 3–15, 1965.