Rotronic HC2A-S3

Instrumentation

The BCO is equipped with a HC2A-S3 sensor manufactured by Rotronic. The instrument measures relative humidity, temperature and dew point temperature and data are available from 2021-07-09.

The instrument is installed \(29\,\mathrm{m}\) above mean sea level.

The sensor is a HYGROMER® HT-1 and the measurement range for the temperature is -50 to +100 °C, while the relative humidity measurement range is 0 to 100 %. The temperature accuracy is ±0.1 K at 10 to 30 °C, and the relative humidity accuracy is ±0.8 %.

The following variables are provided:

Abbreviation	Variable	Unit
RH	Relative humidity	%
T	Temperature	degree_Celsius
DT	Dew point temperature	degree_Celsius

Data Availability

The data from the Rotronic HC2A-S3 sensor are available as BCO.surfacemet_hc2a in the catalog.

import intake

cat = intake.open_catalog("https://tcodata.mpimet.mpg.de/catalog.yaml")
ds_hc2a = cat.BCO.surfacemet_hc2a.to_dask()
ds_hc2a

/builds/tco/bco/docs/.venv/lib/python3.14/site-packages/intake_xarray/base.py:21: FutureWarning: The return type of `Dataset.dims` will be changed to return a set of dimension names in future, in order to be more consistent with `DataArray.dims`. To access a mapping from dimension names to lengths, please use `Dataset.sizes`.
  'dims': dict(self._ds.dims),

<xarray.Dataset> Size: 880MB
Dimensions:    (time: 14669974)
Coordinates:
  * time       (time) datetime64[ns] 117MB 2021-07-09T12:19:15 ... 2026-10-20
    sensor_id  (time) <U10 587MB dask.array<chunksize=(4194304,), meta=np.ndarray>
    alt        float64 8B ...
    lat        float64 8B ...
    lon        float64 8B ...
Data variables:
    DT         (time) float32 59MB dask.array<chunksize=(4194304,), meta=np.ndarray>
    RH         (time) float32 59MB dask.array<chunksize=(4194304,), meta=np.ndarray>
    T          (time) float32 59MB dask.array<chunksize=(4194304,), meta=np.ndarray>
Attributes:
    Conventions:           CF-1.12
    _logical_cutoff_date:  2026-10-20T00:00:00Z
    bcoproc_version:       0.0.0.post2301.dev0+58a3748
    featureType:           timeSeries
    institution:           Max Planck Institute for Meteorology, Hamburg
    license:               CC-BY-4.0
    location:              The Barbados Cloud Observatory (BCO), Deebles Poin...
    platform:              BCO
    source:                Rotronic HC2A-S3
    summary:               HC2A-S3 dew point, temperature, and relative humid...
    title:                 Humidity sensor HC2A-S3 data from BCO (Level 1)
    tool_versions:         {"Python": "3.14.3 (main, Mar  3 2026, 14:59:53) [...

xarray.Dataset

• Dimensions:
  • time: 14669974
• Coordinates: (5)
  • time
    (time)
    datetime64[ns]
    2021-07-09T12:19:15 ... 2026-10-20

    axis :

    T

    standard_name :

    time

    units_metadata :

    leap_seconds: utc

    array(['2021-07-09T12:19:15.000000000', '2021-07-09T12:19:20.000000000',
           '2021-07-09T12:19:25.000000000', ..., '2026-10-19T23:58:00.000000000',
           '2026-10-19T23:59:00.000000000', '2026-10-20T00:00:00.000000000'],
          shape=(14669974,), dtype='datetime64[ns]')

  • sensor_id
    (time)
    <U10
    dask.array<chunksize=(4194304,), meta=np.ndarray>

    long_name :

    Rotronic HC2A sensor serial number

    Array Chunk Bytes 559.62 MiB 160.00 MiB Shape (14669974,) (4194304,) Dask graph 4 chunks in 2 graph layers Data type

  • alt
    ()
    float64
    ...

    long_name :

    height above mean sea level

    standard_name :

    altitude

    units :

    m

    [1 values with dtype=float64]

  • lat
    ()
    float64
    ...

    long_name :

    north latitude

    units :

    degree_north

    valid_max :

    90.0

    valid_min :

    -90.0

    [1 values with dtype=float64]

  • lon
    ()
    float64
    ...

    long_name :

    east longitude

    units :

    degree_east

    valid_max :

    180.0

    valid_min :

    -180.0

    [1 values with dtype=float64]

• Data variables: (3)
  • DT
    (time)
    float32
    dask.array<chunksize=(4194304,), meta=np.ndarray>

    long_name :

    dew point temperature

    units :

    degree_Celsius

    Array Chunk Bytes 55.96 MiB 16.00 MiB Shape (14669974,) (4194304,) Dask graph 4 chunks in 2 graph layers Data type float32 numpy.ndarray

  • RH
    (time)
    float32
    dask.array<chunksize=(4194304,), meta=np.ndarray>

    long_name :

    relative humidity

    units :

    %

    Array Chunk Bytes 55.96 MiB 16.00 MiB Shape (14669974,) (4194304,) Dask graph 4 chunks in 2 graph layers Data type float32 numpy.ndarray

  • T
    (time)
    float32
    dask.array<chunksize=(4194304,), meta=np.ndarray>

    long_name :

    temperature

    units :

    degree_Celsius

    Array Chunk Bytes 55.96 MiB 16.00 MiB Shape (14669974,) (4194304,) Dask graph 4 chunks in 2 graph layers Data type float32 numpy.ndarray

• Attributes: (12)

  Conventions :

  CF-1.12

  _logical_cutoff_date :

  2026-10-20T00:00:00Z

  bcoproc_version :

  0.0.0.post2301.dev0+58a3748

  featureType :

  timeSeries

  institution :

  Max Planck Institute for Meteorology, Hamburg

  license :

  CC-BY-4.0

  location :

  The Barbados Cloud Observatory (BCO), Deebles Point, Barbados, West Indies

  platform :

  BCO

  source :

  Rotronic HC2A-S3

  summary :

  HC2A-S3 dew point, temperature, and relative humidity measurements at the BCO

  title :

  Humidity sensor HC2A-S3 data from BCO (Level 1)

  tool_versions :

  {"Python": "3.14.3 (main, Mar 3 2026, 14:59:53) [Clang 21.1.4 ]", "networkx": "3.6.1", "aiosignal": "1.4.0", "pandas": "3.0.5", "iniconfig": "2.3.0", "wrapt": "2.4.0", "MarkupSafe": "3.0.3", "pytest": "9.1.1", "cloudpickle": "3.1.2", "yarl": "1.24.5", "netcdf4": "1.7.4", "partd": "1.4.2", "python-dateutil": "2.9.0.post0", "aiohappyeyeballs": "2.7.1", "platformdirs": "4.11.8", "datarecords": "0.0.0.post2301.dev0+58a3748", "bcoproc": "0.0.0.post2301.dev0+58a3748", "jinja2": "3.1.6", "aiohttp": "3.14.3", "dask": "2026.8.0", "numcodecs": "0.15.1", "fsspec": "2026.7.0", "pluggy": "1.6.0", "multidict": "6.8.0", "packaging": "26.3", "scipy": "1.18.1", "locket": "1.0.0", "netCDF4": "1.7.4", "flox": "0.11.2", "xarray": "2026.7.0", "numpy": "2.5.3", "frozenlist": "1.8.0", "six": "1.17.0", "bcologs": "0.0.0.post2301.dev0+58a3748", "intake": "2.0.8", "certifi": "2026.7.22", "cftime": "1.6.5", "deprecated": "1.3.1", "pygments": "2.21.0", "pyyaml": "6.0.3", "attrs": "26.1.0", "propcache": "0.5.2", "toolz": "1.1.0", "zarr": "2.18.7", "asciitree": "0.3.3", "numpy_groupies": "0.11.3", "tzdata": "2026.3", "ruff": "0.13.0", "pendulum": "3.2.0", "idna": "3.19", "click": "8.5.0"}

Sample Plot

ds_hc2a["DT"].sel(time="2024").resample(time="1D").mean().plot(label="Dew point")
ds_hc2a["T"].sel(time="2024").resample(time="1D").mean().plot(label="Temperature")

[<matplotlib.lines.Line2D at 0x7fd21e2d0ec0>]