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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/ 
table is comprised of in situ observations between 1997 
and 2012, with a global distribution, and include the fol 
lowing variables: remote-sensing reflectance (rrs), chloro 
phyll a concentration (chla), algal pigment absorption co 
efficient (aph), detrital and coloured dissolved organic mat 
ter absorption (adg), particle backscattering coefficient (bbp), 
and diffuse attenuation coefficient for downward irradiance 
(kd). All observations in the table were processed in such a 
way that they can be compared directly with satellite-derived 
ocean-colour data. The table consists of 80524 rows and 
267 columns. Each row represents a unique station in space 
and time, separated from each other by at least 5 min and 
200 m. For each observation in a given station, there are three 
metadata strings: dataset, subdataset and pi. The columns of 
the table take the form described in Table 1. The contrib 
utors of data in the table are shown in Table 2. Regarding 
spectral variables, all original wavelengths were preserved, 
which requires a large number of unique wavelengths to be 
maintained in the database. No band shifting was performed 
(though some archived data in SeaBASS and MERMAID 
may have been merged with nearby wavelengths) and no 
minimum number of wavelengths per observation was im 
posed. This allows further manipulation of the table for dif 
ferent purposes. In the following paragraphs, the table is 
analysed and the final group of observations is described 
for each contributing dataset; however, the numbers reported 
here do not reflect the original numbers in each dataset, since 
duplicates across contributing datasets were removed (e.g. 
removed NOMAD and others from MERMAID). 
Observations of remote-sensing reflectance are available 
at 134 unique wavelengths (i.e. columns), between 405 and 
1022.1 nm (Fig. 1). In total there are 44 191 observations (i.e. 
rows) with remote-sensing reflectance in the table. The to 
tal number of observations are partitioned per contributing 
datasets as follows: AERONET-OC (17 405), BOUSSOLE 
(17 364), MOBY (4513), NOMAD (3326), MERMAID 
(885) and SEABASS (698). The data from AERONET-OC, 
BOUSSOLE and MOBY correspond to continuous time se 
ries and hence the higher number of observations. The data 
distribution at 44X nm and 55 Y nm is provided in Fig. 2a 
and b, respectively. Data were first searched at 445 and 
555 nm and then with a search window of up to 8 nm to 
also include data at 547 nm. Median values at 44X nm range 
from 0.003 m“ 1 (AERONET-OC) and 0.009 m“ 1 (MOBY), 
whereas at 55X nm the median values lie between 0.001 m“ 1 
(MOBY) and 0.004 m“ 1 (AERONET-OC). The observations 
are evenly distributed on a monthly basis in the Northern 
Hemisphere (Fig. 3). In the Southern Hemisphere, where the 
number of stations is smaller, there is a decrease in the num 
ber of observations during the austral winter months (Fig. 3). 
For additional analysis, rrs band ratios were plotted against 
each other (490:555 vs. 412: 443, Fig. 4). Most points are 
within the boundaries of the NOMAD dataset, but some scat 
tered points were found. These points were retained in the ta 
ble to allow further manipulation with different quality con- 
Table 1. The standard variables, nomenclatures and units in the fi 
nal table. 
Variable/column 
Description and units 
time 
GMT, <YYYY-MM-DD>T<HH:MM:SS>Z 
lat 
Decimal degree, —90:90, south negative 
Ion 
Decimal degree, —180: 180, west negative 
depth_water 
Sampling depth (m) - all assigned to zero 
chla_hplc 
Total chlorophyll a concentration determined 
from HPLC method (mg m —3 ) 
chlajluor 
Chlorophyll a concentration determined from 
fluorometric or spectrophotometric methods 
(mgm“ 3 ) 
rrs_<band> 
Remote-sensing reflectance (sr — 
aph_<band> 
Algal pigment absorption coefficient (m — *) 
adg_<band> 
Detrital plus CDOM absorption coefficient 
(m“ 1 ) 
bbp_<band> 
Particle backscattering coefficient (m — *) 
kd_<band> 
Diffuse attenuation coefficient for downward 
irradiance (m — 
etopol 
Water depth from ETOPOl (m) 
chla_hplc_dataset 
Metadata string for chlajbplc 
chla_hplc_subdataset 
Metadata string for chlajbplc 
chla_hplc_pi 
Metadata string for chlajbplc 
chia fluor dataset 
Metadata string for chla_fluor 
chla_fluor_subdataset 
Metadata string for chla_fluor 
chla_fluor_pi 
Metadata string for chla_fluor 
rrs_dataset 
Metadata string for rrs 
rrs_subdataset 
Metadata string for rrs 
rrs_pi 
Metadata string for rrs 
aph_dataset 
Metadata string for aph 
aph_subdataset 
Metadata string for aph 
aph_pi 
Metadata string for aph 
adg_dataset 
Metadata string for adg 
adg_subdataset 
Metadata string for adg 
adg_pi 
Metadata string for adg 
bbp_dataset 
Metadata string for bbp 
bbp_subdataset 
Metadata string for bbp 
bbp_pi 
Metadata string for bbp 
kd_dataset 
Metadata string for kd 
kd_subdataset 
Metadata string for kd 
kd_pi 
Metadata string for kd 
trol criteria. Complementary analysis of remote-sensing re 
flectance data is made when other variables are concurrently 
available and discussed further on in the text (see Figs. 11 
and 16). The geographic distribution of remote-sensing re 
flectance observations (Fig. 5) shows a higher number of ob 
servations in some coastal regions, such as those of North 
America and Northern Europe. The central regions of the 
ocean show a lower number of observations, with the At 
lantic Ocean having the highest density in relation to the 
other oceans. Best geographic coverage is provided by the 
NOMAD database. Data from SeaBASS are smaller in num 
ber but are still important. Data from MERMAID are mainly 
located along the coasts of Europe, North America and the 
central region of the North Atlantic Ocean. 
For chlorophyll a concentration, two types of observa 
tions were compiled, one measured by fluorometric or spec- 
trophotometric methods (chla_fluor), and the other measured