examples/draw_climatology_map_MISR_AOD.py

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"""
    draw_climatology_map_MISR_AOD.py

    Use OCW to download an MISR dataset, subset the data, calculate the 16 and 5 year
    mean and draw a countour map of the means and the current values.

    In this example:

    1. Download a dataset from https://dx.doi.org/10.6084/m9.figshare.3753321.v1.
    ***  Note *** The dataset for this example is not downloaded as part of the example
    and must be downloaded to examples directory before running the example.
    *** Note *** Depending on the OS on which the example is being run, the download
    may remove the - in the filename.  Rename the file appropriately.
    2. Subset the data set (lat / lon / start date / end date).
    3. Calculate the 16, 5 and 1 year mean.
    4. Draw a three contour maps using the calculated means and current values.

    OCW modules demonstrated:

    1. datasource/local
    2. dataset
    3. dataset_processor
    4. plotter

"""

from __future__ import print_function

import numpy as np
import numpy.ma as ma

import ocw.data_source.local as local
import ocw.dataset as ds
import ocw.dataset_processor as dsp
import ocw.plotter as plotter

# data source: https://dx.doi.org/10.6084/m9.figshare.3753321.v1
#    AOD_monthly_2000-Mar_2016-FEB_from_MISR_L3_JOINT.nc is publicly available.
dataset = local.load_file('AOD_monthly_2000-MAR_2016-FEB_from_MISR_L3_JOINT.nc',
                          'nonabsorbing_ave')
# Subset the data for East Asia.
Bounds = ds.Bounds(lat_min=20, lat_max=57.7, lon_min=90, lon_max=150)
dataset = dsp.subset(dataset, Bounds)

# The original dataset includes nonabsorbing AOD values between March 2000 and February 2015.
# dsp.temporal_subset will extract data in September-October-November.
dataset_SON = dsp.temporal_subset(
    dataset, month_start=9, month_end=11, average_each_year=True)

ny, nx = dataset_SON.values.shape[1:]

# multi-year mean aod
clim_aod = ma.zeros([3, ny, nx])

clim_aod[0, :] = ma.mean(dataset_SON.values, axis=0)  # 16-year mean
clim_aod[1, :] = ma.mean(dataset_SON.values[-5:, :],
                         axis=0)  # the last 5-year mean
clim_aod[2, :] = dataset_SON.values[-1, :]  # the last year's value

# plot clim_aod (3 subplots)
plotter.draw_contour_map(clim_aod, dataset_SON.lats, dataset_SON.lons,
                         fname='nonabsorbing_AOD_clim_East_Asia_Sep-Nov',
                         gridshape=[1, 3], subtitles=['2000-2015: 16 years', '2011-2015: 5 years', '2015: 1 year'],
                         clevs=np.arange(21) * 0.02)