DOI: 10.5061/dryad.tqjq2bw5f
title: Physical and biogeochemical properties of California Current upwelled source waters

description: Coastal upwelling variability in the California Current region, one of the
 four main eastern boundary current upwelling systems, is controlled by
 processes acting over a wide range of spatial and temporal scales. While
 the ensuing ecosystem response depends strongly on upwelled water
 properties, determining their exact physical and biogeochemical
 characteristics is notoriously difficult as it requires tracking water
 masses backward in space and time from the moment they upwell near the
 coast to their subsurface origin. Adjoint model simulations have been used
 successfully to track water masses in coastal upwelling systems and the
 work presented here extends these applications to determining the
 co-variability of physical and biogeochemical properties of source waters
 at spatial scales that resolve the known alongshore variability of coastal
 upwelling dynamics in the region. Notably, the results identify that the
 modulation of coastal upwelling efficiency by onshore/offshore geostrophic
 meanders is the dominant mechanism explaining alongshore variability in
 source depth and properties of upwelled waters. The simulations also
 reveal that source water properties vary seasonally in response to
 different balances between coastal upwelling intensity and biogeochemical
 processes. During spring, interannual variability of physical and
 biogeochemical properties is directly tied to the intensity of
 upwelling-favorable alongshore winds, whereas, during summer,
 biogeochemical properties respond more strongly to biological activity and
 subsequent organic matter remineralization at depth. Overall, the present
 work provides important insight into the mechanisms responsible for the
 alongshore mosaic and seasonal variation upwelled source water properties
 in the central California Current region.
description: This dataset is derived from adjoint passive tracer simulations
 for the central California Current upwelling system. The physical model is
 an implementation of the Regional Ocean Modelling System (ROMS; www.myroms.org)
 coupled to NEMUCSC, a customized version of the North Pacific Ecosystem
 Model for Understanding Regional Oceanography (NEMURO). The adjoint model
 is used to track backward-in-time passive tracer concentrations
 originating from nearshore locations where upwelled water masses are
 typically found in the central CCS. The simulations are implemented such
 that adjoint passive tracers at any time in the past represent the source
 locations of water masses initially present over a 14-day period in 0.5°
 alongshore bins extending 0–30 km offshore and 0–20 m deep. The adjoint
 simulations The dataset was produced with Ferret V7.1 (http://ferret.pmel.noaa.gov/Ferret) and is in NetCDF4 format (CF-1.4 compliant) with metadata describing each variable name and associated units.
description: # Physical and biogeochemical properties of California Current upwelled
 source waters
 [https://doi.org/10.5061/dryad.tqjq2bw5f](https://doi.org/10.5061/dryad.tqjq2bw5f) ## Description of the data and file structure The dataset is in NetCDF4 format (CF-1.4 compliant) with metadata describing each variable name and associated units. Variables in the dataset represent the geographical (longitude, latitude, and depth), physical (density anomaly and spiciness), and biogeochemical (nitrate, ammonium, particulate organic nitrogen, dissolved oxygen, and pH) properties of upwelled source waters in the central California Current during spring (May-June) and summer (July-August). Each source water property is associated with a year (1990-2010) and the nearhsore subregion (16 0.5 deg. alonshore coastal bins between 35-43N) to which it contributes. ## Sharing/Access information Any software capable of reading NetCDF4 format can be used to open the data file. All necessary information to use this dataset is contained in the metadata (variable name, units, missing value flag, etc). ## Code/Software No code/software is shared.