MATLAB: How to average Multiple months of 2D data

time average

The data im using is shown below. as you can see there are multiple values for temperature and salinity at each lat lon location due to multiple time intervals. I want to average the temperatures and salinity respectively at each location to plot a pcolor of the average temp and salinity over the entire time period. Does anyone know how to average the 4D matrix int a 3D matrix?
Dimensions: [1x4 struct]
     Variables: [1x6 struct]
    Attributes: [1x15 struct]
        Groups: []
        Format: 'classic'
Format:
           classic
Global Attributes:
           title           = 'monthly mean fields from Global Ocean Physics Analysis and Forecast updated monthly'
           institution     = 'Mercator Ocean'
           references      = 'http://marine.copernicus.eu'
           source          = 'MERCATOR PSY4QV3R1'
           Conventions     = 'CF-1.0'
           history         = 'Data extracted from dataset http://opendap-glo.mercator-ocean.fr:8080/thredds/dodsC/global-analysis-forecast-phy-001-024-monthly'
           time_min        = 543852
           time_max        = 569412
           julian_day_unit = 'hours since 1950-01-01'
           z_min           = 55.7643
           z_max           = 55.7643
           latitude_min    = -8
           latitude_max    = -2
           longitude_min   = 69
           longitude_max   = 80
Dimensions:
           time      = 36
           depth     = 1
           latitude  = 73
           longitude = 133
Variables:
    time     
           Size:       36x1
           Dimensions: time
           Datatype:   int32
           Attributes:
                       units               = 'hours since 1950-01-01'
                       axis                = 'T'
                       long_name           = 'Time (hours since 1950-01-01)'
                       standard_name       = 'time'
                       calendar            = 'gregorian'
                       _CoordinateAxisType = 'Time'
    so       
           Size:       133x73x1x36
           Dimensions: longitude,latitude,depth,time
           Datatype:   int16
           Attributes:
                       _CoordinateAxes = 'time depth latitude longitude '
                       _FillValue      = -32767
                       long_name       = 'Salinity'
                       standard_name   = 'sea_water_salinity'
                       units           = '1e-3'
                       unit_long       = 'Practical Salinity Unit'
                       cell_methods    = 'area: mean'
                       add_offset      = -0.0015259
                       scale_factor    = 0.0015259
    thetao   
           Size:       133x73x1x36
           Dimensions: longitude,latitude,depth,time
           Datatype:   int16
           Attributes:
                       _CoordinateAxes = 'time depth latitude longitude '
                       _FillValue      = -32767
                       long_name       = 'Temperature'
                       standard_name   = 'sea_water_potential_temperature'
                       units           = 'degrees_C'
                       unit_long       = 'Degrees Celsius'
                       cell_methods    = 'area: mean'
                       add_offset      = 21
                       scale_factor    = 0.00073244
    longitude
           Size:       133x1
           Dimensions: longitude
           Datatype:   single
           Attributes:
                       _FillValue          = NaN
                       step                = 0.083328
                       units               = 'degrees_east'
                       unit_long           = 'Degrees East'
                       long_name           = 'Longitude'
                       standard_name       = 'longitude'
                       axis                = 'X'
                       _CoordinateAxisType = 'Lon'
    latitude 
           Size:       73x1
           Dimensions: latitude
           Datatype:   single
           Attributes:
                       _FillValue          = NaN
                       step                = 0.083336
                       units               = 'degrees_north'
                       unit_long           = 'Degrees North'
                       long_name           = 'Latitude'
                       standard_name       = 'latitude'
                       axis                = 'Y'
                       _CoordinateAxisType = 'Lat'
    depth    
           Size:       1x1
           Dimensions: depth
           Datatype:   single
           Attributes:
                       _FillValue             = NaN
                       units                  = 'm'
                       positive               = 'down'
                       unit_long              = 'Meters'
                       long_name              = 'Depth'
                       standard_name          = 'depth'
                       axis                   = 'Z'
                       _CoordinateAxisType    = 'Height'
                       _CoordinateZisPositive = 'down'
Related Question