Skip to content

Ocean clustering

Jump to bottom
Bror Jonsson edited this page Nov 7, 2019 · 10 revisions

This this is a repository of information, code, and algorithms to be used for clustering and classification projects in ocean sciences.

The first version is based on different datasets resampled in space to the Darwin 1/2° grid and aggregated in time to monthly climatologies.

Datasets

Sea Surface Temperature

We use two different products for SST: MODIS-A 4 ’”“m daytime SST \citep{modis_sst} and the ESA SST CCI Analysis Long Term Product \citep[SST-CCI][]{Merchant2016, cci_sst}, consisting of daily, spatially complete fields of obtained by combining the orbit data from the AVHRR and ATSR ESA SST CCI Long Term Products and using optimal interpolation to provide SSTs where there are no measurements. SST measured by MODIS infrared radiometers is commonly referred to as the skin temperature of the ocean since the observed radiance originates in the top 1mm skin layer of the ocean and not the body of water below \citep{Hanafin2013}. SST-CCI provides a more representative SST at the foundation depth defined as the starting point of the diurnal cycle that will develop over a day, or at 20 cm depth 10:30 in the morning local time. The SST-CCI product is orginally on a 1/12\degree grid with full daily coverage. We upscale the daily fields to the OC-CCI grid using the SatPy resampling package \citep{pytroll} and mask out any grid cells with invalid data in the OC-CCI dataset.

  • Salinity
  • Reflectance

Chlorophyll

Chl is sourced from the level 4 blended Climate Change Initiative (CCI) Ocean Colour product \citep[OC-CCI][]{Melin2017} where data from SeaWiFS, MERIS, MODIS-A, and VIIRS is merged to a unified product. The atmospheric correction for MODIS-A and MERIS was performed through the POLYMER algorithm (Steinmetz et al., 2011) and cloud flagging for MERIS and SeaWiFS adopted an advanced scheme (CCI, 2016b). As result, OC-CCI provides a more extensive temporal coverage than any individual instrument.

Mixed layer depth

Based on the Monthly Isopycnal / Mixed-layer Ocean Climatology (MIMOC) with a range from 80°S to 90°N, an 0.5° lateral resolution, and a monthly resolution in time. The fields are based mostly on Argo CTD data, supplemented by shipboard and Ice-Tethered Profiler CTD data. The products mostly reflect the modern ocean state, although they relax back to historic data from as early as the 1970s when no recent data are available for a region or season.

https://www.pmel.noaa.gov/mimoc/

Original datasets

  • Bottom depth
  • Wind speed
  • Ekman pumping
  • Kd
  • Euphotic depth
  • Eddy Kinetic Energy
  • PAR
Clone this wiki locally