SMART dataset

The following script exemplifies the access and usage of SMART data measured during EUREC4A. The Spectral Modular Airborne Radiation measurement sysTem (SMART) measures downward irradiances in the solar spectral range between 300 nm and 2200 nm.

More information on the dataset can be found in [SAB+19] and [WMSH01]. If you have questions or if you would like to use the data for a publication, please don’t hesitate to get in contact with the dataset authors as stated in the dataset attributes contact or author.

Get data

  • To load the data we first load the EUREC4A meta data catalogue. More information on the catalog can be found here.

import eurec4a
cat = eurec4a.get_intake_catalog()
  • We can further specify a product and a flight and obtain the dataset using to_dask.


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

ds_smart = cat.HALO.SMART.spectral_irradiances['HALO-0205'].to_dask()
Dimensions:               (time: 32730)
  * time                  (time) datetime64[ns] 2020-02-05T09:15:53 ... 2020-...
Data variables:
    alt                   (time) float32 7.43 10.15 13.67 ... 9.08 7.35 6.15
    lat                   (time) float32 13.08 13.08 13.08 ... 13.07 13.07 13.07
    lon                   (time) float32 -59.49 -59.49 -59.49 ... -59.5 -59.5
    sza                   (time) float32 106.8 106.8 106.8 ... 43.12 43.12 43.13
    saa                   (time) float32 103.1 103.1 103.1 ... 228.7 228.7 228.7
    F_down_solar_wl_422   (time) float32 nan nan nan ... 0.7839 0.8679 0.6831
    F_down_solar_wl_532   (time) float32 nan nan nan ... 0.8907 0.9862 0.7493
    F_down_solar_wl_648   (time) float32 nan nan nan ... 0.7222 0.7977 0.5979
    F_down_solar_wl_858   (time) float32 nan nan nan ... 0.4979 0.5443 0.4152
    F_down_solar_wl_1238  (time) float32 -0.06112 -0.06111 ... -0.0166 -0.07509
    F_down_solar_wl_1638  (time) float32 -20.89 -20.89 ... -0.6221 -0.7722
    Title:                Spectral downward irradiance measured by SMART duri...
    campaign:             EUREC4A
    platform:             HALO
    Research_Flight_Day:  2020/20/05
    Version:              Revision 3 from 2021/01/24
    comment_1:            BAHAMAS data was processed by DLR, contact Andreas ...
    Contact:              Andre Ehrlich, University Leipzig, a.ehrlich@uni-le...

The available dataset includes irradiances for six selected wavelengths (422nm, 532nm, 648nm, 858nm, 1238nm, 1638nm). The full dataset is available on demand. Contact the dataset authors as stated in the dataset attributes contact.

First Quickplot of whole flight (one wavelength)

%matplotlib inline
import matplotlib.pyplot as plt"./mplstyle/book")


Load HALO flight phase information

All HALO flights were split up into flight phases or segments to allow for a precise selection in time and space of a circle or calibration pattern. For more information have a look at the respective github repository.

meta = eurec4a.get_flight_segments()

We select the flight phase we are interested in, e.g. the second circle on February 5 by it’s segment_id.

segments = {s["segment_id"]: {**s, "flight_id": flight["flight_id"]}
             for platform in meta.values()
             for flight in platform.values()
             for s in flight["segments"]
seg = segments["HALO-0205_c2"]

We transfer the information from our flight segment selection to our radar and radiometer data in the xarray dataset.

ds_smart_selection = ds_smart.sel(time=slice(seg["start"], seg["end"]))


We plot the spectral irradiances from different wavelengths measured with SMART during the selected flight segment.

fig, ax = plt.subplots()
for i in wl_list:
    ds_smart_selection[f'F_down_solar_wl_{i}'].plot(label =f'{i} nm')
ax.set_ylabel('Spectral downward irradiance / Wm$^{-2}$nm$^{-1}$')