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A.  Valente  et  al.:  A  compilation  of  global  bio-optical  in  situ  data

Earth  Syst.  Sei.  Data,  8,  235-252,  2016

www.earth-syst-sci-data.net/8/235/2016/

adg(443)/adg(490)

adg(412)/adg(443)

aph(490)/aph(443)

aph(412)/aph(443)

_dlb_

1  I

i  i  ■

=  1
:  -kdf-



  -HUH—

1123

1116

1276

1269

0  0.5  1  1.5  2  2.5  3  3.5  4

Figure  13.  The  distribution  of  absorption  coefficient  band  ratios:
adg(443)  /  adg(490),  adg(412)  /  adg(443),  aph(490)  /  aph(443)  and
aph(412)  /  aph(443).  Data  within  2nm  of  the  wavelengths  were
used.  The  graphical  convention  is  identical  to  Fig.  2.  The  vertical
dashed  lines  show  the  lower  and  upper  thresholds  used  for  quality
control  in  the  IOCCG  report  5  (IOCCG,  2006).  The  total  number  of
points  are  divided  between  NOMAD  (93-96  %),  MERMAID  (3-6
  %)  and  SeaBASS  (1%).

Figure  14.  Global  distribution  of  observations  of  inherent  optical
properties  (algal  pigment  absorption  coefficient  aph,  débitai  plus
CDOM  absorption  coefficient  adg  and  particle  backscattering  coefficient ­
  bbp)  in  the  final  table.

Figure  15.  Global  distribution  of  diffuse  attenuation  coefficient  for
downward  irradiance  (kd)  per  dataset  in  the  final  table.

ness,  an  examination  of  bio-optical  relationships  is  provided
(Fig.  16).  The  relation  between  aph  at  443  nm  and  chlorophyll ­
  a  (Fig.  16a)  agrees  with  the  relation  proposed  by
Bricaud  et  al.  (2004).  A  total  of  1070  points  exist  with  these
two  variables  available  (93  %  from  NOMAD).  The  relation
between  the  sum  of  aph  and  adg  at  443  nm  and  rrs  at  443  nm
(Fig.  16b)  shows  a  similar  dispersion,  with  the  exception
of  some  scattered  points,  to  an  equivalent  analysis  on  the
IOCCG  report  5  (see  their  Fig.  2.3).  Again,  the  scattered
data  were  retained  in  the  final  table  to  preserve  the  NOMAD
dataset.  A  total  of  1112  points  exist  for  which  these  three
variables  are  available  (97  %  from  NOMAD).  The  relation
between  the  ratio  rrs(490)  /  rrs(555)  and  kd(490)  (Fig.  16c)
shows  a  good  agreement  with  the  NASA  KD2S  standard  algorithm ­
  (http://oceancolor.gsfc.nasa.gov/cms/atbd/kd_490).
A  total  of  2280  points  exist  for  which  these  three  variables
are  available  (93  %  from  NOMAD).  The  relation  between  the
ratio  rrs(490)  /rrs(555)  and  bbp  at  555  nm  (Fig.  16c)  shows
a  good  agreement  with  the  relation  suggested  by  Tiwari  and
Shanmugam  (2013).  A  total  of  357  points  exist  for  which
these  three  variables  are  available  (91  %  from  NOMAD).

vations,  from  NOMAD  (2266),  SeaBASS  (118)  and  MERMAID ­
  (70).  Data  distribution  of  kd  at  44X  and  55  A  nm  for
each  dataset  is  shown  in  Fig.  12g  and  h.  No  kd  data  at  these
wavelengths  were  available  for  the  SeaBASS  dataset  (only
at  490  nm).  Median  values  of  kd  at  44X  am  span  between
0.08  m“ 1  (NOMAD)  to  0.1m“ 1  (MERMAID),  whereas  at
55X  nm  the  kd  values  are  approximately  0.1  m“ 1  (NOMAD
and  MERMAID).  NOMAD  provides  the  best  geographic
coverage  (Fig.  15),  with  a  higher  coverage  in  the  Atlantic,
compared  with  other  oceans.  With  the  exception  of  the
coastal  regions  of  North  America  and  the  Japan  Sea,  most
coastal  regions  are  not  sampled.  In  the  Northern  Hemisphere,
kd  is  distributed  roughly  evenly  across  all  months  of  the  year,
but  in  the  Southern  Hemisphere  there  are  few  data  points  during ­
  the  austral  winter  and  none  at  all  in  September  (Fig.  3).
Although  most  of  the  stations  with  concurrent  variables ­
  are  mainly  from  the  NOMAD  dataset,  for  complete-4

  Conclusions
A  compilation  of  bio-optical  in  situ  data  is  presented  in  this
work.  The  compiled  data  have  global  coverage  and  span  from
1997  to  2012,  covering  the  recent  period  of  ocean-colour
satellite  observations.  They  resulted  from  the  acquisition,  homogenisation ­
  and  integration  of  several  sets  of  data  obtained
from  different  sources.  Minimal  changes  were  made  to  the
original  data,  except  for  those  necessary  for  conversion  to
standard  format  and  quality  control.  In  situ  measurements  of
the  following  variables  were  compiled:  remote-sensing  reflectance, ­
  chlorophyll  a  concentration,  algal  pigment  absorption ­
  coefficient,  detrital  and  coloured  dissolved  organic  matter ­
  absorption  coefficient,  particle  backscattering  coefficient
and  diffuse  attenuation  coefficient  for  downward  irradiance.
The  final  set  of  data  consists  of  a  substantial  number  of  in
situ  observations,  available  in  a  simple  text  table,  and  processed ­
  in  a  way  that  could  be  used  directly  for  the  evaluation