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# In-cloud vertical motion retrieval

Florian Poydenot (florian.poydenot@mpimet.mpg.de), August 2026

This folder contains a retrieval of vertical wind inside precipitating shallow clouds,
obtained from a radar-based estimate combined with lidar observations. The vertical
motion is retrieved from the slowest-moving edge of the radar spectrum, then corrected
for SNR and turbulence broadening, following Zhu et al. (2021). For a detailed description
of the processing, see Poydenot et al. (2026). The resulting data has 30 m/2 s resolution,
with uncertainty of 0.2 m/s above cloud base.

The processing code is available at https://zenodo.org/records/19221500.

## Instruments used 

### Ka-band radars

* MBR2: August 2019-January 2023
* MBRS: January 2023-December 2025

### Lidars

* WindLidar1: vertically-pointing mode between March 2016 and October 2019,
then between July 2021 and September 2024, and again since September 2025
* WindLidar2: VAD scans between March 2019 and July 2021, vertically-pointing mode
between September 2024 and September 2025

## How to use

The vertical coordinate is the radar range.
Do not use the retrieved winds in deep convective clouds as the retrieval is not suited
for this regime (use the provided cloud masks to filter it out).

## Data Availability

The processing is not integrated (yet) into our automated workflows, and as a result, the dataset
does not grow by the day but has an end date determined by when the last round of manual processing was run.

```{code-cell} python
import intake

cat = intake.open_catalog("https://tcodata.mpimet.mpg.de/catalog.yaml")
ds = cat.BCO.verticalwind.to_dask()
mbrs = cat.BCO.mbrs.to_dask().sel(range=slice(None, ds.range.values[-1]))
ds
```

## Sample Plot

```{code-cell} python
rainy_orcestra = slice("2024-09-23T11:45", "2024-09-23T12:35")
ds.sel(time=rainy_orcestra).w.plot(x="time")
```

```{code-cell} python
mbrs.sel(time=rainy_orcestra).Ze.plot(x="time")
```

## References:

1. Zhu, Z., Kollias, P., Yang, F. & Luke, E. On the Estimation of In-Cloud Vertical Air
Motion Using Radar Doppler Spectra. Geophysical Research Letters 48, e2020GL090682 (2021).
2. Poydenot, F., Robbins-Blanch, N., Zhu, Z. & Vogel, R. How rain shapes cloud-scale
dynamics and mass flux in the trades. EGUsphere 1–25 (2026) doi:10.5194/egusphere-2026-1974.