Dataset: particle_absorp
Deployment: TT054

See Platform deployments for cruise specific documentation

Arabian Sea particulate absorption data

Process Cruises 2, 6 and 7

Chuck Trees
Particulate absorption methodology
Arabesque 1 and Process Cruises 2, 6 and 7

Particulate matter was collected by filtering approximately 1.1 liters of
sample through 25 mm GF/F glass fiber filters having a nominal pore size
of 0.7 micrometers.  Spectral absorption was measured on a Perkin-Elmer
Lambda 3b dual beam spectrophotometer.  Diffuse absorption coefficients
for total particulate matter was calculated using the equations described
in the SeaWiFS Optical Protocols (Mueller and Austin, 1995) and a pathlength
amplification factor determined from two diatom cultures.  The amplification
factor, beta, is calculated by plotting optical densities on a filter versus
optical densities in suspension and fitting a 2nd order polynomial to the
data.  The Beta factor for the Lambda 3b is

	ODs = 0.3090*(ODf) + 0.5473*(ODf)**2,

	r**2 = 0.993.

Hot methanol was used to extract pigmented compounds from the filtered
sample, and the bleached filter was then measured to estimate detrital
absorption.  The difference between the two measurements represent absorption
by phytoplankton pigments.  The units for the particulate absorption are
in per meter; measurements have been scaled by the volume filtered and
the area of the filter on which the particles were deposited.

Charles C. Trees
Center for Hydro-Optics and Remote Sensing
San Diego State University

ctrees@chors.sdsu.edu

   PI:              Chuck Trees
   of:              San Diego State University
   dataset:         Particulate absorption data
   dates:           October 29, 1995 to November 25, 1995
   location:        N: 24.3274  S: 10.0823  W: 56.4858  E: 67.1664
   project/cruise:  Arabian Sea/TTN-053 - Process Cruise 6 (bio-optics)
   ship:            Thomas Thompson
 

 

Arabian Sea particulate absorption data

Process Cruises 2, 6 and 7

Chuck Trees
Particulate absorption methodology
Arabesque 1 and Process Cruises 2, 6 and 7

Particulate matter was collected by filtering approximately 1.1 liters of
sample through 25 mm GF/F glass fiber filters having a nominal pore size
of 0.7 micrometers.  Spectral absorption was measured on a Perkin-Elmer
Lambda 3b dual beam spectrophotometer.  Diffuse absorption coefficients
for total particulate matter was calculated using the equations described
in the SeaWiFS Optical Protocols (Mueller and Austin, 1995) and a pathlength
amplification factor determined from two diatom cultures.  The amplification
factor, beta, is calculated by plotting optical densities on a filter versus
optical densities in suspension and fitting a 2nd order polynomial to the
data.  The Beta factor for the Lambda 3b is

	ODs = 0.3090*(ODf) + 0.5473*(ODf)**2,

	r**2 = 0.993.

Hot methanol was used to extract pigmented compounds from the filtered
sample, and the bleached filter was then measured to estimate detrital
absorption.  The difference between the two measurements represent absorption
by phytoplankton pigments.  The units for the particulate absorption are
in per meter; measurements have been scaled by the volume filtered and
the area of the filter on which the particles were deposited.

Charles C. Trees
Center for Hydro-Optics and Remote Sensing
San Diego State University

ctrees@chors.sdsu.edu