SimpleEddyDetection
Simple Oceanic Mesoscale Eddy Detection based on sea level anomaly (sla)
Note:
- This function is provided "as is" without warranty of any kind.
- One should be careful if using it in scientific research as its eddy identification approach is quite simple.
Dependency:
Matlab toolbox "M_Map" is required.
Inputs:
lon: longitude, vector or matrix generated by "meshgrid" with range between [-180,180]
lat: latitude, vector or matrix generated by "meshgrid" with range between [-90,90]
sla: (spatial high-pass filtered) sea level anomaly (unit: meter) falls within the area defined by viarable "lon" and "lat". Continent or no value at grid point is masked with "NaN".
upperFolderName: a string to signify the upper folder name or path.
whichYear: The year of data "sla". Only an integer is accepted.
whichMonth: The month of data "sla". Only an integer is accepted.
whichDay: The day of data "sla". Only an integer is accepted. Can be replaced by "[]".
whichHour: The hour of data "sla". Only an integer is accepted. Can be replaced by "[]".
amplitudeThreshold (optional): unit: cm. Default is 3 cm. Note: this is an artificial threshold that an detected eddy is required to meet this criterion.
radiusThreshold (optional): unit: Km. Default is 45 Km, designed for altimetry data due to its resolving capability. Note: this is an artificial threshold that an detected eddy is required to meet this criterion.
Outputs:
Eddy: a structure array contains the properties of detected eddies:
Eddy.type: polarity of detected eddy. -1 for cyclonic while 1 for anticyclonic.
Eddy.center: longitude and latitude of eddy centroid.
Eddy.amplitude: longitude and latitude of eddy's sla extreme as well as eddy's amplitude (set to positive no matter if it is cyclonic or anticyclonic. Unit: cm)
Eddy.radius: radius of an circle that has the same area as the eddy area enclosed by the eddy edge. Unit: Km
Eddy.edge: two vectors specify the longitudes and latitudes of eddy edge defined by the outermost closed sla contour.