Production of the raw data on the Lagrangian temperature anomaly decomposition by Mayer and Wirth (2025)

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Short summary:

In the Lagrangian temperature anomaly decomposition by Mayer and Wirth (2025) a given potential temperature anomaly is decomposed from a Lagrangian perspective into contributions from different processes. The contributions were computed using the tracer method of Mayer and Wirth (2023). The contributions from horizontal transport, vertical transport, diabatic heating, and seasonality are direct output from the tracer advection code implementing the tracer method and are therefore considered raw data on the Lagrangian temperature anomaly decomposition. 

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Information on input data:

ERA5 reanalysis data on modellevels (Hersbach et al., 2017) provided by the Copernicus Climate Change Service.

Period: 20 February - 30 September of each year between 2010 - 2022
Temporal resolution: 3 hours
Horizontal resolution: 1° x 1° (regridded from a resoultion of 0.25° x 0.25° using cdo's remapcon function)
Vertical resolution: 44 modellevels (modellevels 50, 52, 54, ..., 134, 136)
Latitudinal extent: -90°N to 90°N
Longitudinal extent: -180°E to 180°E
Variables: sp (surface pressure), u (zonal wind), v (meridional wind), etadot (Eta-coordinate vertical velocity), w: the pressure vertical velocity (omega) [Pa/s], t (temperature)

The computations of the contributions from horizontal transport and vertical transport require knowledge about the climatological potential temperature (gradient). The climatological potential temperature was obtained by computing potential temperature on modellevels followed by linearly interpolating potential temperature from modellevels to pressure levels. Climatological means were then obtained by first computing the temporal averages specific for each day of the year and time of the day followed by a smoothing employing a moving average to the day and time-of-the-day specific averages with a window size of +/-15 days. The years emcompassed in the climatology were 2010 to 2022.

All input data have been archived on the irods server of the Johannes Gutenberg University Mainz.

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Information on data processing:

For each year and each tracer (contribution), an individual run has been started.
Start date: 20 Feb of each year
End date: 30 Sep of each year

The period before 1 March has been considered as spin
up time and has been removed from the data.

A relaxation constant of 1 / (7 days) has been used.

Computation of the contributions from horizontal transport, vertical transport, and seasonality:
	Used tracer advection code:
	- branch clim_advection_directly
	- commit cbd702bd24332a7c08d225ef6ea90d7f360e9457 (horizontal, vertical) 
	- commit 8f42ea9e550665c556b1a8331a8a32015cbd9a38 (seasonality)
	The used code implements equation (18) from Mayer and Wirth (2023). 
	In this formulation of the advection-relaxation-problem the source term is explicitly included in the equation.

Computation of the contribution from diabatic heating:
	Used tracer advection code:
	- branch dev
	- commit 6349c422a30b057be2bf4f2788c23635b9e2b49b
	The used code implements equations (19)/(20) from Mayer and Wirth (2023). 
	In this formulation of the advection-relaxation-problem the source term is only implicitly included in the equation.

The used tracer advection code has been archived online (Mayer, 2025).

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Information on output data:

Period: 1 March - 30 September of each year between 2010 - 2022
Temporal resolution: 3 hours
Horizontal resolution: 1° x 1°
Vertical resolution: 44 pressure levels between 56 hPa and 1010 hPa
Latitudinal extent: -90°N to 90°N
Longitudinal extent: -180°E to 180°E
file type: netcdf

All output data have been archived on the irods server of the Johannes Gutenberg University Mainz.

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References: 

Mayer, A. and Wirth, V.: Two different perspectives on heatwaves within the Lagrangian framework, Weather and Climate Dynamics, 2025.

Mayer, A.: The Tracer Method by Mayer and Wirth, ZENODO [code], https://doi.org/10.5281/zenodo.14697529, 2025.

Mayer, A. and Wirth, V.: Lagrangian description of the atmospheric flow from Eulerian tracer advection with relaxation, Quarterly Journal of the Royal Meteorological Society, 149, 1271–1292, https://doi.org/10.1002/qj.4453, 2023.

Hersbach, H., Bell, B., Berrisford, P., Hirahara, S., Horányi, A., Muñoz-Sabater, J., Nicolas, J., Peubey, C., Radu, R., Schepers, D., Simmons, A., Soci, C., Abdalla, S., Abellan, X., Balsamo, G., Bechtold, P., Biavati, G., Bidlot, J., Bonavita, M., De Chiara, G., Dahlgren, P., Dee, D., Diamantakis, M., Dragani, R., Flemming, J., Forbes, R., Fuentes, M., Geer, A., Haimberger, L., Healy, S., Hogan, R. J., Hólm, E., Janisková, M., Keeley, S., Laloyaux, P., Lopez, P., Lupu, C., Radnoti, G., de Rosnay, P., Rozum, I., Vamborg, F., Villaume, S., and Thépaut, J.:  Complete ERA5 from 1940: Fifth generation of ECMWF atmospheric reanalyses of the global climate, Copernicus Climate Change Service (C3S) Data Store (CDS), https://doi.org/10.24381/cds.143582cf, 2017. (last accessed on 02-10-2023)

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In case of any questions, please contact Amelie Mayer (amelie.mayer@uni-mainz.de).


