PMS probes and Nevzorov#

The following example presents the data collected by the PMS and Nevzorov probes on Polar 5 during the AFLUX and MOSAiC-ACA campaigns. The PMS probes where attached to the wings of the aircraft and operated by the group at DLR e.V. and JGU Mainz namely: C. Voigt, M. Moser, Yvonne Boose, and V. Hahn. If you have questions or if you would like to use the data for a publication, please get in contact with the dataset authors as stated above and in the dataset attributes contact or author. The data has been uploaded to the PANGAEA data base for both campaigns: AFLUX and MOSAiC-ACA.

Data access#

To analyse the data they first have to be loaded by importing the (AC)³ airborne meta data catalogue. To do so the ac3airborne package has to be installed. More information on how to do that and about the catalog can be found here.

import ac3airborne
cat = ac3airborne.get_intake_catalog()

Nevzorov#

First, we load the data collected by the Nevzorov.

datasets = []
for campaign in ['MOSAiC-ACA']:
    datasets.extend(list(cat[campaign]['P5']['NEVZOROV']))
datasets
['MOSAiC-ACA_P5_RF03',
 'MOSAiC-ACA_P5_RF05',
 'MOSAiC-ACA_P5_RF06',
 'MOSAiC-ACA_P5_RF07',
 'MOSAiC-ACA_P5_RF08',
 'MOSAiC-ACA_P5_RF09',
 'MOSAiC-ACA_P5_RF10',
 'MOSAiC-ACA_P5_RF11']

Note

Have a look at the attributes of the xarray dataset ds_nevzorov for all relevant information on the dataset, such as author, contact, or citation information.

flight_id = 'MOSAiC-ACA_P5_RF11' # id of flight we work on
ds_nevzorov = cat['MOSAiC-ACA']['P5']['NEVZOROV'][flight_id].to_dask()
ds_nevzorov
<xarray.Dataset>
Dimensions:        (time: 20801)
Coordinates:
  * time           (time) datetime64[ns] 2020-09-13T09:20:14 ... 2020-09-13T1...
Data variables:
    twc            (time) float64 0.0002671 0.00016 9.64e-05 ... 1.5e-06 1e-07
    lwc            (time) float64 -8.39e-05 -0.000236 ... 3.71e-05 2.41e-05
    twc_corrected  (time) float64 0.0002378 0.0001506 8.69e-05 ... 0.0 0.0 0.0
    lwc_corrected  (time) float64 0.0 0.0 0.0 0.0 0.0 ... 0.0 0.0 0.0 0.0 0.0
Attributes: (12/14)
    version:      0.1
    contact:      christiane.voigt@dlr.de, manuel.moser@dlr.de, valerian.hahn...
    institution:  DLR e.V., JGU Mainz
    author:       Prof. Dr. Christiane Voigt, Manuel Moser, Valerian Hahn, Jo...
    Convention:   CF-1.8
    featureType:  trajectory
    ...           ...
    instruments:  Nevzorov probe
    mission:      MOSAiC-ACA
    platform:     AWI-Polar 5, BT-67 C-GAWI
    uncertainty:  contact PI
    flight_id:    RF11
    history:      acquired by Polar 5 during MOSAiC-ACA campaign and quality ...

The dataset includes the liquid water content (lwc) and total water content (twc).

PMS#

Next, we load the data from the different instruments of the PMS to determine total number concentration, particle size distributions and water contents.

  • Cloud Droplet Probe (CDP) with 2 to 50 microns

  • Cloud Imaging Probe (CIP) with 7.5 to 967.5 microns

  • Precipitation Imaging Probe (PIP) with 51.5 to 6643.5 microns

ds_cdp = cat['MOSAiC-ACA']['P5']['CDP'][flight_id].to_dask()
ds_cip = cat['MOSAiC-ACA']['P5']['CIP'][flight_id].to_dask()
ds_pip = cat['MOSAiC-ACA']['P5']['PIP'][flight_id].to_dask()
ds_pms_combined = cat['MOSAiC-ACA']['P5']['PMS_COMBINED'][flight_id].to_dask()
ds_pms_combined
<xarray.Dataset>
Dimensions:    (bins: 93, time: 20132)
Coordinates:
  * time       (time) datetime64[ns] 2020-09-13T09:20:01 ... 2020-09-13T14:59:12
  * bins       (bins) int32 1 2 3 4 5 6 7 8 9 10 ... 85 86 87 88 89 90 91 92 93
Data variables:
    bin_min    (bins) float64 2.8 4.8 7.6 10.1 ... 6.334e+03 6.438e+03 6.54e+03
    bin_max    (bins) float64 4.8 7.6 10.1 11.7 ... 6.438e+03 6.54e+03 6.644e+03
    bin_mid    (bins) float64 3.8 6.2 8.85 ... 6.386e+03 6.489e+03 6.592e+03
    bin_width  (bins) float64 2.0 2.8 2.5 1.6 1.9 ... 103.0 103.0 103.0 103.0
    N          (time) float64 9.375e+04 0.07137 21.95 231.9 ... 0.0 0.0 0.0 0.0
    CWC        (time) float64 7.931e-07 4.168e-10 1.282e-07 ... 0.0 0.0 0.0
    ED         (time) float64 0.0005536 0.0003785 0.0003785 ... 0.0 0.0 0.0
    MVD        (time) float64 0.0006904 0.0003785 0.0003785 ... 0.0 0.0 0.0
    dNdD       (time, bins) float64 ...
Attributes: (12/14)
    version:      0.1
    contact:      christiane.voigt@dlr.de, manuel.moser@dlr.de, valerian.hahn...
    institution:  DLR e.V., JGU Mainz
    author:       Prof. Dr. Christiane Voigt, Manuel Moser, Valerian Hahn
    Convention:   CF-1.8
    featureType:  trajectory
    ...           ...
    instruments:  CDP, CIP, PIP - combined
    mission:      MOSAiC-ACA
    platform:     AWI-Polar 5, BT-67 C-GAWI
    uncertainty:  contact PI
    flight_id:    RF11
    history:      acquired by Polar 5 during MOSAiC-ACA campaign and quality ...

The dataset ds_pms_combined combines the measurements from the different instruments of the PMS and hence includes total number concentration (N), median volume diameter (MVD), liquid water content (LWC), ice water content (IWC) and particle number concentration (dNdD).

Load Polar 5 flight phase information#

Polar 5 flights are divided into segments to easily access start and end times of flight patterns. For more information have a look at the respective github repository.

At first we want to load the flight segments of (AC)³airborne

meta = ac3airborne.get_flight_segments()
flight = meta['MOSAiC-ACA']['P5'][flight_id]

Here, we want to have a look on the size distributions measured during different legs of a racetrack_pattern. In order to simplify things we can import the module flightphase from the ac3airborne.tools.

from ac3airborne.tools import flightphase

We can now select only the racetrack_pattern. This kind of pattern is available two times.

flight_query = flightphase.FlightPhaseFile(flight)
queried = flight_query.selectKind(['racetrack_pattern'])
len(queried)
/home/mech/.local/lib/python3.10/site-packages/ac3airborne/tools/flightphase.py:27: UserWarning: the segment MOSAiC-ACA_P5_RF11_rt01 contains following irregularities: first leg begins far away from starting point of the other legs and is therefore longer
  warnings.warn(str)
2

Plots#

%matplotlib inline
import matplotlib.pyplot as plt
import matplotlib.dates as mdates
plt.style.use("../../mplstyle/book")
fig, (ax1, ax2, ax3, ax4) = plt.subplots(4, 1, sharex=True, gridspec_kw=dict(height_ratios=(1, 1, 1, 1)))
ax1.semilogy(ds_cdp.time, ds_cdp.N, color='k')
ax1.set_title('CDP')
ax2.semilogy(ds_cip.time, ds_cip.N, color='b')
ax2.set_title('CIP')
ax3.semilogy(ds_pip.time, ds_pip.N, color='g')
ax3.set_title('PIP')
ax4.plot(ds_nevzorov.time, ds_nevzorov.lwc, '--', color='g', label='LWC')
ax4.plot(ds_nevzorov.time, ds_nevzorov.twc, '--', color='b', label='TWC')
ax4.set_title('Nevzorov')

ax1.set_ylabel('N [$1/m^3$]')
ax2.set_ylabel('N [$1/m^3$]')
ax3.set_ylabel('N [$1/m^3$]')

ax4.set_ylabel('water content [kg/m^3]')

ax4.legend(frameon=False, loc='upper right')

ax4.xaxis.set_major_formatter(mdates.DateFormatter('%H:%M'))

plt.show()
../../_images/nevzorov_and_pms_22_0.png
from matplotlib import cm
import numpy as np
def colors(n):
    """Creates set of random colors of length n"""
    
    cmap = cm.get_cmap('gist_rainbow')
    rnd = np.random.uniform(low=0, high=1, size=n)
    cols = cmap(rnd)
    
    return cols
titles = ['ice','ocean']
fig, axs = plt.subplots(1, 2, gridspec_kw=dict())
for i, rtp in enumerate(queried):
    col_segments = colors(len(rtp['parts']))
    for j,part in enumerate(rtp['parts']):
        if 'leg' in part['name']:
            ds_sel = ds_pms_combined.sel(time=slice(part['start'],part['end']))
            axs[i].loglog(ds_sel.bin_mid, ds_sel.dNdD.mean(dim='time'), 'o',color=col_segments[j],label=part['levels'][0])
    axs[i].legend(frameon=False)
    axs[i].set_xlabel('D[$\mu m$]')
    axs[i].set_ylabel('N[$m^{-4}$]')
    axs[i].set_title('Over '+titles[i])
../../_images/nevzorov_and_pms_24_0.png