Dataset: aerosols_short
Deployment: TT048

Aerosols, short irradiation neutron activation analysis

Principal Investigator:

Dr Neil Tindale (Texas A&M University, TAMU)

BCO-DMO Data Manager:

Cynthia L. Chandler (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Project:

U.S. JGOFS Arabian Sea (Arabian Sea)

Version:

June 30, 1997

Deployment Synonyms:

TTN048, TN048, TTN-048

Version Date:

1997-06-30

Data URL:

https://www.bco-dmo.org/dataset-deployment/450744/data

Expand/Collapse All

Description

  PI:              Neil Tindale
  of:              Texas A&M University
  dataset:         Aerosols, short irradiation neutron activation analysis
  dates:           January 08, 1995 to December 25, 1995 
  location:        N: 23.7953  S: 09.9776  W: 57.2609  E: 68.7641
  project:         Arabian Sea
  ship:            Thomas Thompson

  PI Notes and Methodology
  A note from DMO on supplementary fields

HiVol pump sampler methods are described in: N. W. Tindale and P. P. Pease, Aerosols
over the Arabian Sea: Atmospheric transport pathways and concentrations of dust
and sea salt, Deep Sea Research Part II: Topical Studies in OceanographyVolume 46,
Issues 8-9, August 1999, Pages 1577-1595.

( href="http://www.sciencedirect.com/science/article/B6VGC-3Y0RMGY-3/2/e32070ccfcbd49427d79b1b5e77699e6">view article at ScienceDirect )

Methods & Sampling

Dataset acquisition description

  PI:              Neil Tindale
  of:              Texas A&M University
  dataset:         Aerosols, short irradiation neutron activation analysis
  dates:           January 08, 1995 to December 25, 1995 

  location:        N: 23.7953  S: 09.9776  W: 57.2609  E: 68.7641
  project:         Arabian Sea
  ship:            Thomas Thompson

Dr. Neil Tindale, Texas A & M Univ.
JGOFS/Arabian Sea
Aerosols, short and long irradiation neutron activation analysis


JGOFS Arabian Sea Aerosol Data

This mineral aerosol concentration data set is from samples collected
during several cruises on the R/V Thomas Thompson during the JGOFS
Arabian Sea field program.  The data set includes the sampling period
for each sample; the "Day of Year", yrday, number for the start of the
sampling period for each sample;  and the concentration of different
elements for each sample, in micrograms per cubic meter.  For the
sampling period, "nd" is used as a filler to indicate "no data" gaps in
the data array.  The dust values are estimated using aluminum
concentrations determined by neutron activation analysis.  While most
samples cover a multi-day period, we only have data for about 150
days.  We didn't participate in all of the cruises and, on the cruises
where samples were collected, often sampling conditions were less than
ideal (bad weather, ship maneuvering, relative wind from astern etc.).
A few samples that were collected showed obvious contamination from
local sources, presumably from material from the R/V Thompson or from
nearby fishing boats, and these samples were discarded and are not
included in the data set.  While the sampling period represents the
period during which sampling occurred, sampling was usually not
continuous.   Sampling was frequently stopped, whenever sampling
conditions were no longer suitable.  Thus the concentration value at
any particular date represents a time integrated sample which is
usually non-continuous.

Cautionary comments:
1.  There may be a problem with the estimate for the mineral "dust"
concentration.  Most researchers use the average crustal ratio to estimate
mineral dust concentrations using elemental concentration data (Al, Fe,
etc.).  Surface sand and silt samples that were collected in Oman in the
Wahibah Sands region have distinct, non-crustal ratios.  If individual
aerosol samples are comprised of material from distinct sources, including
Oman, then it is not unreasonable for their elemental ratios to differ from
the published "average" crustal ratio that is used in most aerosol studies.

2.  The amount of Ti in all the aerosol samples was small, despite there
being a reasonable amount of dust material in most samples.  The peaks for
Cr and Ti overlap in the neutron activation short irradiation analysis and
if significant quantities of Cr are present, this will interfere with the Ti
analysis.  With the exception of one sample, the Ti values are at or below
the detection limit.  The sole value above the detection limit was corrected
for the Cr contribution using a correction based on the Cr values from the
long irradiations.  The correction changed the Ti value by less than 5%.
The Ti data flagged as being at or below the detection limit was not
corrected for possible Cr interference.

Data management office notes on supplementary fields - aerosols data

lat, lon

A nominal ship location is given in lat/lon.  The location is the noon
position most near the middle of the sampling period, e.g. for a sample
which was pumped intermittently from Jan. 3 - 5, the location is given for
noon, Jan. 4.  Intended as an aid to understanding, not a discrete location.

date_begin, date_end

We have included the start and stop day for each sample which we
believe constrains the sample time about as well as is useful for these
data.  We also have pump volume and thus a mean concentration of dust
per cubic meter of air for that time frame.  The actual number of hours
sampled during a time block (number of days) is complicated to
present.  Pumps were turned on and off repetitively depending upon ship
maneuvers and relative wind direction (to prevent ship exhaust
contamination).  Also, the total number of hours the pumps were on is a
less useful measure than pump volume, because of the variability in
pump efficiency due to changing barometric pressures. An hours worth of
pumping does not always yield the same volume of air.

Deployment-specific acquisition description

  PI:              Neil Tindale
  of:              Texas A&M University
  dataset:         Aerosols, short irradiation neutron activation analysis
  dates:           January 08, 1995 to December 25, 1995 

  location:        N: 23.7953  S: 09.9776  W: 57.2609  E: 68.7641
  project:         Arabian Sea
  ship:            Thomas Thompson

Dr. Neil Tindale, Texas A & M Univ.
JGOFS/Arabian Sea
Aerosols, short and long irradiation neutron activation analysis


JGOFS Arabian Sea Aerosol Data

This mineral aerosol concentration data set is from samples collected
during several cruises on the R/V Thomas Thompson during the JGOFS
Arabian Sea field program.  The data set includes the sampling period
for each sample; the "Day of Year", yrday, number for the start of the
sampling period for each sample;  and the concentration of different
elements for each sample, in micrograms per cubic meter.  For the
sampling period, "nd" is used as a filler to indicate "no data" gaps in
the data array.  The dust values are estimated using aluminum
concentrations determined by neutron activation analysis.  While most
samples cover a multi-day period, we only have data for about 150
days.  We didn't participate in all of the cruises and, on the cruises
where samples were collected, often sampling conditions were less than
ideal (bad weather, ship maneuvering, relative wind from astern etc.).
A few samples that were collected showed obvious contamination from
local sources, presumably from material from the R/V Thompson or from
nearby fishing boats, and these samples were discarded and are not
included in the data set.  While the sampling period represents the
period during which sampling occurred, sampling was usually not
continuous.   Sampling was frequently stopped, whenever sampling
conditions were no longer suitable.  Thus the concentration value at
any particular date represents a time integrated sample which is
usually non-continuous.

Cautionary comments:
1.  There may be a problem with the estimate for the mineral "dust"
concentration.  Most researchers use the average crustal ratio to estimate
mineral dust concentrations using elemental concentration data (Al, Fe,
etc.).  Surface sand and silt samples that were collected in Oman in the
Wahibah Sands region have distinct, non-crustal ratios.  If individual
aerosol samples are comprised of material from distinct sources, including
Oman, then it is not unreasonable for their elemental ratios to differ from
the published "average" crustal ratio that is used in most aerosol studies.

2.  The amount of Ti in all the aerosol samples was small, despite there
being a reasonable amount of dust material in most samples.  The peaks for
Cr and Ti overlap in the neutron activation short irradiation analysis and
if significant quantities of Cr are present, this will interfere with the Ti
analysis.  With the exception of one sample, the Ti values are at or below
the detection limit.  The sole value above the detection limit was corrected
for the Cr contribution using a correction based on the Cr values from the
long irradiations.  The correction changed the Ti value by less than 5%.
The Ti data flagged as being at or below the detection limit was not
corrected for possible Cr interference.

Data management office notes on supplementary fields - aerosols data

lat, lon

A nominal ship location is given in lat/lon.  The location is the noon
position most near the middle of the sampling period, e.g. for a sample
which was pumped intermittently from Jan. 3 - 5, the location is given for
noon, Jan. 4.  Intended as an aid to understanding, not a discrete location.

date_begin, date_end

We have included the start and stop day for each sample which we
believe constrains the sample time about as well as is useful for these
data.  We also have pump volume and thus a mean concentration of dust
per cubic meter of air for that time frame.  The actual number of hours
sampled during a time block (number of days) is complicated to
present.  Pumps were turned on and off repetitively depending upon ship
maneuvers and relative wind direction (to prevent ship exhaust
contamination).  Also, the total number of hours the pumps were on is a
less useful measure than pump volume, because of the variability in
pump efficiency due to changing barometric pressures. An hours worth of
pumping does not always yield the same volume of air.

Data Processing Description

Dataset Processing Description

More information about this dataset deployment

Funding

Award Number	Funding Source
unknown Arabian Sea NASA	National Aeronautics & Space Administration

Instruments

Pump Air Sampler

Supplied Description:

Air sampling pumps, were mounted in a 6-m shipping container located on the foredeck's container storage rack. The air sampler was a HiVol system loaded with a single unwashed Whatman 41t "lter and with a #ow rate of&1.2}1.4 m3 min~1.

Instrument Type

Generic Name: Pump Air Sampler

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/58/

Generic Description:

A Pump Air Sampler is an instrument that continuously supplies a flow of air either to an analytical instrument, over a sensor, through filters or from which discrete samples may be drawn for subsequent analysis. This instrument designation is used when specific make and model are not known.

Parameters

Supplied Name	Supplied description	Supplied Units	Standard Name
cruise	Arabian Sea, Thomas Thompson cruise identifier		cruiseid
date_begin	date sampling pump turned on for a given sample,	as YYYYMMDD	date_begin
date_end	date sampling pump turned off for a given sample, as YYYYMMDD		date_end
yrday	day of year, 1995		yrday
lat_n	Nominal latitude (minus indicates South)	decimal degrees	lat_n
lon_n	Nominal longitude (minus indicates West)	decimal degrees	no_bcodmo_term
vol_pump	volume of air pumped to accumulate sample	cubic meter	no_bcodmo_term
Al	concentration of Aluminum	ug/m^3	no_bcodmo_term
Ca	concentration of Calcium	ug/m^3	no_bcodmo_term
Mg	concentration of Magnesium	ug/m^3	no_bcodmo_term
Mn	concentration of Manganese	ug/m^3	no_bcodmo_term
Na	concentration of Sodium	ug/m^3	no_bcodmo_term
Si	concentration of Silicon	ug/m^3	Si
Ti	concentration of Titanium	ug/m^3	no_bcodmo_term
V	concentration of Vanadium	ug/m^3	v
dust	total sample mass estimated by assuming the Al content represented 8 percent, based on a crustal average for Al of 8%	ug/m^3	no_bcodmo_term
Al_err	Aluminum combined sampling and analytical error	ug/m^3	no_bcodmo_term
Al_dl	Aluminum detection level: a '1' indicates that while a peak was detected, the isotope sample was below the level of detection relative to background "noise". The element concentration reported therefore represents the amount of the isotope which would have had to have been present for it to have been detected. a '0' indicates no flag - concentration is as measured.		no_bcodmo_term
Ca_err	Calcium combined sampling and analytical error	ug/m^3	no_bcodmo_term
Ca_dl	Calcium detection level: a '1' indicates that while a peak was detected, the isotope sample was below the level of detection relative to background "noise". The element concentration reported therefore represents the amount of the isotope which would have had to have been present for it to have been detected. a '0' indicates no flag - concentration is as measured.		no_bcodmo_term
Mg_err	Magnesium combined sampling and analytical error	ug/m^3	no_bcodmo_term
Mg_dl	Magnesium detection level: a '1' indicates that while a peak was detected, the isotope sample was below the level of detection relative to background "noise". The element concentration reported therefore represents the amount of the isotope which would have had to have been present for it to have been detected. a '0' indicates no flag - concentration is as measured.		no_bcodmo_term
Mn_err	Manganese combined sampling and analytical error	ug/m^3	no_bcodmo_term
Mn_d	Manganese detection level: a '1' indicates that while a peak was detected, the isotope sample was below the level of detection relative to background "noise". The element concentration reported therefore represents the amount of the isotope which would have had to have been present for it to have been detected. a '0' indicates no flag - concentration is as measured.		no_bcodmo_term
Na_err	Sodium combined sampling and analytical error	ug/m^3	no_bcodmo_term
Na_dl	Sodium detection level: a '1' indicates that while a peak was detected, the isotope sample was below the level of detection relative to background "noise". The element concentration reported therefore represents the amount of the isotope which would have had to have been present for it to have been detected. a '0' indicates no flag - concentration is as measured.		no_bcodmo_term
Si_err	Silicon combined sampling and analytical error	ug/m^3	no_bcodmo_term
Si_dl	Silicon detection level: a '1' indicates that while a peak was detected, the isotope sample was below the level of detection relative to background "noise". The element concentration reported therefore represents the amount of the isotope which would have had to have been present for it to have been detected. a '0' indicates no flag - concentration is as measured.		no_bcodmo_term
Ti_err	Titanium combined sampling and analytical error	ug/m^3	no_bcodmo_term
Ti_dl	Titanium detection level: a '1' indicates that while a peak was detected, the isotope sample was below the level of detection relative to background "noise". The element concentration reported therefore represents the amount of the isotope which would have had to have been present for it to have been detected. a '0' indicates no flag - concentration is as measured.		no_bcodmo_term
V_err	Vanadium combined sampling and analytical error	ug/m^3	no_bcodmo_term
V_dl	Vanadium detection level: a '1' indicates that while a peak was detected, the isotope sample was below the level of detection relative to background "noise". The element concentration reported therefore represents the amount of the isotope which would have had to have been present for it to have been detected. a '0' indicates no flag - concentration is as measured.		no_bcodmo_term
dust_err	total sample mass combined sampling and analytical error	ug/m^3	no_bcodmo_term
dust_dl	total sample mass detection level: a '1' indicates that while a peak was detected, the isotope sample was below the level of detection relative to background "noise". The element concentration reported therefore represents the amount of the isotope which would have had to have been present for it to have been detected. a '0' indicates no flag - concentration is as measured.		no_bcodmo_term

Database

Contribute Data

Dataset: aerosols_short
Deployment: TT048

Dataset acquisition description

Dr. Neil Tindale, Texas A & M Univ. JGOFS/Arabian Sea Aerosols, short and long irradiation neutron activation analysis

Data management office notes on supplementary fields - aerosols data

Deployment-specific acquisition description

Dr. Neil Tindale, Texas A & M Univ. JGOFS/Arabian Sea Aerosols, short and long irradiation neutron activation analysis

Data management office notes on supplementary fields - aerosols data

Dataset Processing Description

Database

Contribute Data

Dataset: aerosols_shortDeployment: TT048

Dataset acquisition description

Dr. Neil Tindale, Texas A & M Univ. JGOFS/Arabian Sea Aerosols, short and long irradiation neutron activation analysis

Data management office notes on supplementary fields - aerosols data

Deployment-specific acquisition description

Dr. Neil Tindale, Texas A & M Univ. JGOFS/Arabian Sea Aerosols, short and long irradiation neutron activation analysis

Data management office notes on supplementary fields - aerosols data

Dataset Processing Description

Dataset: aerosols_short
Deployment: TT048