NOMAD: NASA bio-Optical Marine Algorithm Dataset

NOMAD is a publicly available, global, high quality in situ bio-optical data set for use in ocean color algorithm development and satellite data product validation activities. Data products include coincident observations of water-leaving radiances and chlorophyll a concentrations, along with relevant metadata, such as the date, time, and coordinates of data collection and binary processing flags. Inherent optical properties (IOPs; e.g., spectral absorption and backscattering coefficients) and aerosol optical thicknesses have been or will be included in the near future. The entire dataset is available via a digital text file provided below under Downloads. Additional background details, such as the motivation for creating such a data set, and a historical perspective of such data sets, are provided in the Werdell and Bailey reference listed below.


NOMAD is available for research uses only. It was compiled by the NASA Ocean Biology Processing Group at Goddard Space Flight Center, Maryland, USA, using generous data contributions from the ocean color research community. Source bio-optical data are available online via a suite of SeaBASS Search Engines. Optimum interpolation (OI) sea surface temperature (SST) data were acquired from the NOAA Climate Diagnostics Center. ETOPO2 water depths were acquired from the NOAA National Geophysical Data Center. NOMAD Data access and use are governed by the SeaBASS Data Access Policy. Please direct comments, questions, and identified outliers to the SeaBASS Administrator.

Table of Contents

IOP data processing documentation

Evaluation, processing, and distribution of Inherent Optical Properties
Spectrophotometric absorption processing evaluation data set ( map )
Backscattering processing evaluation data set ( map )


Download Version (right click and choose "save as")
Map Date Last Updated
Current NOMAD data set (version 2.a) Map v2.a 18 July, 2008    
Original NOMAD data set (version 1.3) Map v1.3 19 Sept, 2005

The NOMAD data set downloads are provided as comma-delimited ASCII text.

Version 2.1 was developed in support of the OOXIX IOP Algorithm Workshop on 3-4 Oct 2008.
Version 1.x updates:
Backscattering coefficients were updated on 19 Sep 2005.
Update from version 1.2 (17 Aug 2005): Backscattering coefficients added.
Update from version 1.1 ( 6 Jul 2005): Spectrophotometric absorption coefficients added.
Update from version 1.0 (30 Mar 2005): Bulk water temperature and salinity added to data set.

Additional evaluation products

High performance liquid chromotography (HPLC) pigments subset ( map )
Limited to NOMAD stations where HPLC data are available, 22 Feb 2007
SeaWiFS satellite-to-in situ validation subset ( map )
Limited to NOMAD stations with coincident and valid SeaWiFS coverage, 8 Mar 2007

Acknowledgments & Citation


Data were contributed by participants in the NASA SIMBIOS Program ( NRA-96-MTPE-04 and NRA-99-OES-09 ) and by voluntary contributors. A cruise name accompanies each data record. Cruise details, including contributors' names, are available online using the General Search and Cruise List utilities to facilitate communication, collaboration, and acknowledgement. Further, NOMAD should be cited as follows. A pre-print is available online in pdf format.


Werdell, P.J. and S.W. Bailey , 2005: An improved bio-optical data set for ocean color algorithm
development and satellite data product validation. Remote Sensing of Environment , 98(1), 122-140.
Last edited by Chris Proctor on 2017-04-24
Created by Chris Proctor on 2012-09-26