California MOCI: MULTIVARIATE OCEAN CLIMATE INDicator
What is MOCI?
MOCI synthesizes a number of local and regional ocean and atmospheric conditions that represent, in a holistic manner, the state of the California coastal ocean. MOCI includes data that are readily available from the Internet so the indicator can be updated and shared regularly via this website.
MOCI, now encompassing 30 years, captures ENSO events across decades, as well as the intensity and phasing of the most recent North Pacific marine heat waves, including the one in 2019. It also shows differences in the magnitude and timing of ocean climate variability in different regions off California. MOCI has skill relative to marine ecosystem dynamics from zooplankton to top predators, and therefore may be important to ecosystem-based fisheries and wildlife management.
Most recent MOCI: Northern, Central, and Southern California MOCI are now updated through March 2024. This season, California MOCI values have started to decline, showing the current El Niño is starting to let up.
**4/23/2024 update: the North Pacific Gyre Oscillation Index is not currently up-to-date, and was not included in this iteration of MOCI.
Data are provided in a .csv file.
Northern California (38-42°N), Central California (34.5-38°N), and Southern California (32-34.5
°N) MOCI, AMJ 1994-JFM 2024 [csv].
Please cite this dataset as:
García-Reyes, M. and Sydeman, W.J. (2017). California Multivariate Ocean Climate Indicator (MOCI) [Data set, V2]. Farallon Institute website, http://www.faralloninstitute.org/moci. Accessed [Date].
What data are included in MOCI?
MOCI include seasonal averages of the following data:
Upwelling Index, NOAA [link]
Sea level from shore stations, NOAA [link]
Alongshore wind, sea surface temperature, air temperature, sea level pressure from NOAA buoys [link]
Regional climate indices:
*Note: MOCI is now calculated for a span of 30 years. Gaps in data are filled in using ERA5 reanalysis V5 data.
How to interpret MOCI?
Positive anomalous (red) values reflect warmer than normal conditions with weaker upwelling, often associated with El Niño, while large negative (blue) values reflect cooler than normal conditions and stronger upwelling. However, we discuss below a more specific interpretation of these values, which depends on the season.
What drives these conditions?
As a multivariate index, MOCI reflects variability in multiple indicators of environmental variables. However, the importance of each of these variables in driving the variability of conditions, and therefore MOCI, varies by region.
The figure below shows the individual importance of each variable in determining the variability of MOCI for each region. Size and intensity of color indicates the importance, and the color signifies the relationship (red is a positive influence, blue is a negative one). Across regions, the largest drivers are related to temperature (sea surface temperature, air temperature, sea level) and the climate drivers that are also related to temperature (El Niño Southern Oscillation - ENSO, and Pacific Decadal Oscillation - PDO); however, this influence is much larger in the southern California MOCI. In the northern and central California regions, the upwelling-related indicators (wind stress, upwelling index) have a larger importance than in southern California. Together this indicates that in southern California, conditions are highly dominated by temperature, while in the central and northern regions, upwelling and winds have a larger role.
Another thing to note is that the importance of each variable changes with season. For example, for the southern California MOCI, sea level pressure and the Northern Oscillation Index, both measures of atmospheric pressure, have a larger importance in the fall and winter, but not so much in spring and summer. The same is also true for many climate indicators. Across all California regions, wind and upwelling vary throughout the seasons, but they are surprisingly low in summer. Please view the publication below for additional information on how MOCI is calculated and further interpretation.
More information about MOCI:
García-Reyes M, Sydeman WJ. 2017. California Multivariate Ocean Climate Indicator (MOCI) and marine ecosystem dynamics. Ecological Indicators, 72, 521-529. [pdf]
Sydeman W, Thompson SA, García-Reyes M, Kahru M, Peterson W, Largier J. 2014. Multivariate ocean-climate indicators (MOCI) for the Central California Current: Environmental change: 2010-2014. Progress in Oceanography, 120, 352-369. [pdf]