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Description

This dataset contains Submersible Ultraviolet Nitrate Analyzer (SUNA) nitrate measurements taken during the Sub-Mesoscale Ocean Dynamics Experiment (S-MODE) pilot campaign conducted approximately 300 km offshore of San Francisco over two weeks in October 2021. S-MODE aims to understand how ocean dynamics acting on short spatial scales influence the vertical exchange of physical and biological variables in the ocean. SUNA is a standalone optical nitrate sensor that mounts onto the shipboard CTD rosette cast from the R/V Oceanus. The SUNA measurements are calibrated against bottle nutrient samples taken from the underway flow-through system on the ship and later analyzed with a Lachat Nutrient Analyzer. From the Lachat data, the average concentration of nitrate+nitrite are used for each sample. Data are available in netCDF format.

Product Summary

Platforms
Ships
Instruments
CTD
Spatial Extent

N: 38.1 S: 36.3 E: -122.9 W: -125.4

Coordinate System
CARTESIAN
Granule Spatial Representation
CARTESIAN
Temporal Extent
2021-10-22 to 2021-10-23
Data Partner
Physical Oceanography Distributed Active Archive Center, Jet Propulsion Laboratory, NASA (NASA/JPL/PODAAC)
Concept ID
C2832216518-POCLOUD
Data State
COMPLETE
Number of Files/Granules
1
Processing Level
2
Science Keywords
Nitrate

Citation

Citation is critically important for dataset documentation and discovery. This dataset is openly shared, without restriction, in accordance with the EOSDIS Data Use and Citation Guidance.

Copy Citation

S-MODE. (2022). S-MODE L2 Shipboard SUNA nitrate data Version 1 [Data set]. NASA Physical Oceanography Distributed Active Archive Center. https://doi.org/10.5067/SMODE-RVSUN Date Accessed: 2025-12-14

Documents

Variables

Variables are a set of physical properties whose values determine the characteristics or behavior of something. For example, temperature and pressure are variables of the atmosphere. Parameters and variables can be used interchangeably. Variable level attributes provide individual information for each variable.

The Name in this table is the variable name. Fill value indicates missing or undefined data points in a variable. Valid range is the range of values the variable can store. Scale factor is used to increase or decrease the size of an object and can be used to correct for distortion. For questions on a specific variable, please use the Earthdata Forum.

Name Description Units Data Type Fill Value Valid Range Scale Factor
depth Depth of SUNA nitrate measurement m double N/A N/A 1
latitude Latitude of SUNA nitrate measurement degrees north double N/A N/A 1
longitude Longitude of SUNA nitrate measurement degrees east double N/A N/A 1
nitrate SUNA nitrate measurement micromoles L-1 double -9999 0.25 to 20 1
time Time of SUNA nitrate measurement days since 1950-01-01T00:00:00 double N/A N/A 1
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