MDA8

.gitignore

@@ -156,3 +156,6 @@ sorted_out
 
 # Vim temp files
 *.swp
+
+
+pytest.ini

pyaerocom/colocation/colocator.py

@@ -7,6 +7,7 @@
 import os
 import traceback
 import warnings
+from collections import defaultdict
 from datetime import datetime
 from typing import Any, Callable
 
@@ -30,6 +31,7 @@
 from pyaerocom.io import ReadCAMS2_83, ReadGridded, ReadUngridded
 from pyaerocom.io.helpers import get_all_supported_ids_ungridded
 from pyaerocom.io.mscw_ctm.reader import ReadMscwCtm
+from pyaerocom.stats.mda8.mda8 import mda8_colocated_data
 
 from .colocated_data import ColocatedData
 from .colocation_3d import ColocatedDataLists, colocate_vertical_profile_gridded
@@ -360,7 +362,7 @@ def run(self, var_list: list = None):
             dictionaries comprising key / value pairs of obs variables and
             associated instances of :class:`ColocatedData`.
         """
-        data_out = {}
+        data_out = defaultdict(lambda: dict())
         # ToDo: see if the following could be solved via custom context manager
         try:
             vars_to_process = self.prepare_run(var_list)
@@ -378,9 +380,21 @@ def run(self, var_list: list = None):
                 coldata = self._run_helper(
                     mod_var, obs_var
                 )  # note this can be ColocatedData or ColocatedDataLists
-                if mod_var not in data_out:
-                    data_out[mod_var] = {}
                 data_out[mod_var][obs_var] = coldata
+
+                if obs_var in ["conco3", "vmro3"]:
+                    mda8 = None
+                    try:
+                        mda8 = mda8_colocated_data(
+                            coldata, obs_var=f"{obs_var}mda8", mod_var=f"{mod_var}mda8"
+                        )
+                    except ValueError:
+                        logger.warning(
+                            "Tried calculating mda8 for [%s, %s], but failed.", obs_var, mod_var
+                        )
+                    finally:
+                        data_out[f"{mod_var}mda8"][f"{obs_var}mda8"] = mda8
+
                 self._processing_status.append([mod_var, obs_var, 1])
             except Exception:
                 msg = f"Failed to perform analysis: {traceback.format_exc()}\n"
@@ -397,7 +411,7 @@ def run(self, var_list: list = None):
         self._print_processing_status()
         if self.colocation_setup.keep_data:
             self.data = data_out
-        return data_out
+        return dict(data_out)
 
     def get_nc_files_in_coldatadir(self):
         """

pyaerocom/stats/mda8/mda8.py

@@ -0,0 +1,90 @@
+import numpy as np
+import xarray as xr
+
+from pyaerocom.colocation.colocated_data import ColocatedData
+
+
+def min_periods_max(x: np.ndarray, /, min_periods=1) -> float:
+    """Calculates the max of a 1-dimensional array, returning
+    nan if not a minimum count of valid values exist.
+
+    :param x: 1-dimensional ndarray.
+    :param min_periods: minimum required non-nan values, defaults to 1
+    :return: A single value, which is either nan or a float.
+    """
+    if x.ndim != 1:
+        raise ValueError(f"Unexpected number of dimensions. Got {x.ndim}, expected 1.")
+
+    length = np.sum(~np.isnan(x))
+    if length < min_periods:
+        return np.nan
+
+    return np.nanmax(x)
+
+
+def mda8_colocated_data(coldat: ColocatedData, /, obs_var: str, mod_var: str) -> ColocatedData:
+    """Applies the mda8 calculation to a colocated data object,
+    returning the new colocated data object.
+
+    :param data: The colocated data object.
+    :return: Colocated data object containing
+    """
+    if not isinstance(coldat, ColocatedData):
+        raise ValueError(f"Unexpected type {type(coldat)}. Expected ColocatedData")
+
+    if coldat.ts_type != "hourly":
+        raise ValueError(f"Expected hourly timeseries. Got {coldat.ts_type}.")
+
+    # TODO: Currently order of dims matter in the implementation, so this check is
+    # stricter than it probably should be.
+    if coldat.dims != ("data_source", "time", "station_name"):
+        raise ValueError(
+            f"Unexpected dimensions. Got {coldat.dims}, expected ['data_source', 'time', 'station_name']."
+        )
+
+    cd = ColocatedData(_calc_mda8(coldat.data))
+    cd.data.attrs["var_name"] = [obs_var, mod_var]
+    return cd
+
+
+def _calc_mda8(data: xr.DataArray) -> xr.DataArray:
+    """Calculates the daily max 8h average for an array:
+
+    :param data: The DataArray for which to calculate the mda8. Input
+    should be a DataArray with dimensions ["data_source", "time", "station_name"]
+    (ie. the format of ColocatedData.data) representing hourly data.
+    :return: Equivalently structured DataArray, resampled along the "time"
+    dimension.
+
+    Note:
+    -----
+    The calculation for mda8 is defined as follows:
+    > Eight hours values:         75 % of values (i.e. 6 hours)
+
+    > Maximum daily 8-hour mean:  75 % of the hourly running eight hour
+                             averages (i.e. 18 eight hour averages per
+                             day)
+
+    > The maximum daily eight hour mean concentration will be selected by examining
+    > eight hour running averages, calculated from hourly data and updated each hour.
+    > Each eight hour average so calculated will be assigned to the day on which it
+    > ends i.e. the first calculation period for any one day will be the period from
+    > 17:00 on the previous day to 01:00 on that day; the last calculation period for
+    > any one day will be the period from 16:00 to 24:00 on that day.
+    """
+    mda8 = _daily_max(_rolling_average_8hr(data))
+    mda8.attrs["ts_type"] = "daily"
+    return mda8
+
+
+def _rolling_average_8hr(arr: xr.DataArray) -> xr.DataArray:
+    return arr.rolling(time=8, min_periods=6).mean()
+
+
+def _daily_max(arr: xr.DataArray) -> xr.DataArray:
+    # TODO: Base is deprecated, and using offset="1h" is the proper way to do this.
+    # However this currently breaks the old-dependencies test in CI. Should be
+    # changed in the future.
+    return arr.resample(time="24H", base=1).reduce(
+        lambda x, axis: np.apply_along_axis(min_periods_max, 1, x, min_periods=18)
+    )

tests/stats/mda8/test_mda8.py

@@ -0,0 +1,190 @@
+import numpy as np
+import pytest
+import xarray as xr
+
+from pyaerocom.colocation.colocated_data import ColocatedData
+from pyaerocom.colocation.colocation_3d import ColocatedDataLists
+from pyaerocom.stats.mda8.mda8 import (
+    _calc_mda8,
+    _daily_max,
+    _rolling_average_8hr,
+    mda8_colocated_data,
+)
+from tests.fixtures.collocated_data import coldata
+
+
+@pytest.fixture
+def test_data(time, values) -> xr.DataArray:
+    return xr.DataArray(
+        [[[x] for x in values]],
+        dims=["data_source", "time", "station_name"],
+        coords={"time": time},
+    )
+
+
+@pytest.mark.parametrize(
+    "time,values,exp_mda8",
+    (
+        pytest.param(
+            xr.date_range(start="2024-01-01 01:00", periods=49, freq="1h"),
+            [0] * 49,
+            [0, 0, np.nan],
+            id="zeros",
+        ),
+        pytest.param(
+            xr.date_range(start="2024-01-01 01:00", periods=49, freq="1h"),
+            np.linspace(start=1, stop=49, num=49),
+            [20.5, 44.5, np.nan],
+            id="incrementing-by-1",
+        ),
+        pytest.param(
+            xr.date_range(start="2024-01-01 13:00:00", periods=49, freq="1h"),
+            np.concatenate(  # Sequence 1-7, 3x nan, 11-14, 3x nan, 28-49
+                (
+                    np.arange(start=1, stop=8),
+                    [np.nan] * 3,
+                    np.arange(start=11, stop=25),
+                    [np.nan] * 3,
+                    np.arange(start=28, stop=50),
+                )
+            ),
+            [np.nan] * 3,
+            id="with-nans",
+        ),
+    ),
+)
+def test_calc_mda8(test_data, exp_mda8):
+    mda8 = _calc_mda8(test_data)
+
+    assert mda8.shape[1] == len(exp_mda8)
+
+    assert all(mda8[0, :, 0] == pytest.approx(exp_mda8, abs=0, nan_ok=True))
+
+
+def test_calc_mda8_with_gap():
+    arr1 = xr.DataArray(
+        [[[x] for x in np.linspace(start=1, stop=50, num=50)]],
+        dims=["data_source", "time", "station_name"],
+        coords={"time": xr.date_range(start="2024-01-01 01:00", periods=50, freq="1h")},
+    )
+
+    arr2 = xr.DataArray(
+        [[[x] for x in np.linspace(start=1, stop=50, num=50)]],
+        dims=["data_source", "time", "station_name"],
+        coords={"time": xr.date_range(start="2024-01-04 01:00", periods=50, freq="1h")},
+    )
+
+    arr = xr.concat((arr1, arr2), dim="time")
+
+    mda8 = _calc_mda8(arr)
+
+    assert mda8.shape == (1, 6, 1)
+    pytest.approx(mda8[0, :, 0], [20.5, 44.5, np.nan, 41.25, 44.5, np.nan], abs=10 * 10**-5)
+
+
+@pytest.mark.parametrize("coldataset", ("fake_3d_hr",))
+def test_coldata_to_mda8(coldata):
+    mda8 = mda8_colocated_data(coldata, obs_var="vmro3mda8", mod_var="vmro3mda8")
+
+    assert isinstance(mda8, ColocatedData)
+    assert mda8.metadata["ts_type"] == "daily"
+    assert mda8.metadata["var_name"] == ["vmro3mda8", "vmro3mda8"]
+    assert mda8.shape == (2, 9, 1)
+
+    assert mda8.data.values[0, :, 0] == pytest.approx(
+        [
+            np.nan,
+            np.nan,
+            np.nan,
+            1.18741556,
+            1.18777241,
+            1.18869106,
+            1.18879322,
+            1.18807846,
+            1.18700801,
+        ],
+        abs=10**-5,
+        nan_ok=True,
+    )
+
+    assert mda8.data.values[1, :, 0] == pytest.approx(
+        [
+            np.nan,
+            1.57327333,
+            1.28884431,
+            1.28741556,
+            1.28777241,
+            1.28869106,
+            1.28879322,
+            1.28807846,
+            1.28700801,
+        ],
+        abs=10**-5,
+        nan_ok=True,
+    )
+
+
+@pytest.mark.parametrize(
+    "time,values,exp_ravg",
+    (
+        (
+            xr.date_range(start="2024-01-01 01:00", periods=48, freq="1h"),
+            [0, 1, 2, 3, 4, 5, 6, 7] * 6,
+            [np.nan] * 5 + [2.5, 3] + [3.5] * 41,
+        ),
+        (
+            xr.date_range(start="2024-01-01 01:00", periods=24, freq="1h"),
+            [np.nan, 1, 2, 3, 4, 5, 6, 7] * 3,
+            [np.nan] * 6 + [3.5] + [4] * 17,
+        ),
+        (
+            xr.date_range(start="2024-01-01 01:00", periods=24, freq="1h"),
+            [np.nan, np.nan, 2, 3, 4, 5, 6, 7] * 3,
+            [np.nan] * 7 + [4.5] * 17,
+        ),
+        (
+            xr.date_range(start="2024-01-01 01:00", periods=24, freq="1h"),
+            [np.nan, np.nan, np.nan, 3, 4, 5, 6, 7] * 3,
+            [np.nan] * 24,
+        ),
+    ),
+)
+def test_rollingaverage(test_data, exp_ravg):
+    """
+    Test of rolling average calculation
+    """
+    ravg = _rolling_average_8hr(test_data)
+
+    assert all(ravg[0, :, 0] == pytest.approx(exp_ravg, abs=0, nan_ok=True))
+
+
+@pytest.mark.parametrize(
+    "time,values,exp_daily_max",
+    (
+        (
+            xr.date_range(start="2024-01-01 01:00", periods=48, freq="1h"),
+            np.linspace(1, 48, num=48),
+            [24, 48],
+        ),
+        (
+            xr.date_range(start="2024-01-01 01:00", periods=24, freq="1h"),
+            [np.nan] * 6 + list(range(7, 25)),
+            [24],
+        ),
+        (
+            xr.date_range(start="2024-01-01 01:00", periods=24, freq="1h"),
+            [np.nan] * 7 + list(range(8, 25)),
+            [np.nan],
+        ),
+    ),
+)
+def test_daily_max(test_data, exp_daily_max):
+    """
+    Tests the daily max calculation. Note that "the first calculation period
+    for any one day will be the period from 17:00 on the previous day to 01:00
+    on that day; the last calculation period for any one day will be the period
+    from 16:00 to 24:00 on that day
+    """
+    dmax = _daily_max(test_data)
+
+    assert all(dmax[0, :, 0] == pytest.approx(exp_daily_max, abs=0, nan_ok=True))