Code for ERA5 and IAGOS analysis, quantile mapping, vertical distributions of contrail formation potential and overlap, climatologies, and morphology.

This brief documentation accompanies the two manuscripts:

1. "Correction of temperature and relative humidity biases in ERA5 by bivariate quantile mapping: Implications for contrail classification." and
2. "Morphology and temporal and spatial distribution of non-persistent and persistent contrail formation areas in ERA5", which are / will both be submitted to the journal Atmospheric Chemistry and Physics (ACP)

Download ERA5 data

ERA5 data of tempertaure, relative humidity, wind components, and cloud fraction were download from the ERA5 data catalog (https://doi.org/10.24381/cds.f17050d7). Due to the distribution of IAGOS flights, the focus of the analysis is on a domain between 30N and 70N, where most of the IGAOS observations are available. The latitudes were selected similar to Petzold et al 2020.

The data was downloaded with the following script: ERA5_data_download.py

It is noted that the applied python interface and downloads from the ERA5 data base require a registration on the CDS homepage: https://cds.climate.copernicus.eu/cdsapp#!/home. Please follow the instrctions given on the CDS homepage.

Extraction of temperature, relative humidity, wind components, and fraction of cloud cover from ERA5

ERA5 data is extracted along IAGOS flight trajectories. Flights from the years 2015 to 2021 are used. Extraction is performed with the nearest neighbor method by selecting the temporally and spatially closest ERA5 grid point. The code that was used to extract data from ERA 5 with 1 hour resolution: A01_extract__along_flightpath_1h.py

Quantile mapping

Create cumulative distributions functions for quantile mapping

The inventory of cumulative distribution functions CDFs are created with: A02_create_cdf.py

Application of quantile correction, general data analysis, and plots

The pickled ERA5, IAGOS data, and CDFs are read with: A03_apply_2d_correction.py. This code also applies the quantile mapping corrections and includes the analysis that is presented in the manuscripts.

Contrail formation climatology and morphology

Create cumulative distributions functions for quantile mapping

Vertical distributions of contrail formation potential and vertical overlap were created with: A06_era_3d.py

Climatologies of temperature, relative humidity, windpseed, and persistent contrail formation were created with: A07_monthly_crosssections.py

Relevant citations

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.-N.: The ERA5 global reanalysis, Q. J. Royal Meteorol. Soc., 146, 1999–2049, https://doi.org/10.1002/qj.3803, 2020.

Hersbach, H., Bell, B., Berrisford, P., Biavati, G., Horányi, A., Muñoz Sabater, J., Nicolas, J., Peubey, C., Radu, R., Rozum, I., Schepers, D., Simmons, A., Soci, C., Dee, D., and Thépaut, J.-N.: ERA5 monthly averaged data on single levels from 1940 to present., https://doi.org/10.24381/cds.f17050d7, 2023

Petzold, A., Neis, P., Rütimann, M., Rohs, S., Berkes, F., Smit, H. G. J., Krämer, M., Spelten, N., Spichtinger, P., Nédélec, P., and Wahner, A.: Ice-supersaturated air masses in the northern mid-latitudes from regular in situ observations by passenger aircraft: vertical distribution, seasonality and tropospheric fingerprint, Atmos. Chem. Phys., 20, 8157–8179, https://doi.org/10.5194/acp-20-8157-2020, 2020.

Rap, A., Forster, P. M., Jones, A., Boucher, O., Haywood, J. M., Bellouin, N., and De Leon, R. R.: Parameterization of contrails in the UK Met Office Climate Model, J. Geophys. Res. Atmos., 115, https://doi.org/https://doi.org/10.1029/2009JD012443, 2010.

Schumann, U.: On conditions for contrail formation from aircraft exhausts, Meteorologische Zeitschrift, 5, 1996.

Teoh, R., Schumann, U., Voigt, C., Schripp, T. Shapiro, M., Engberg, Z., Molloy, J., Koudis, G., and Stettler, M. E. J.: Targeted Use of Sustainable Aviation Fuel to Maximize Climate Benefits, Environ. Sci. Technol., https://doi.org/10.1021/acs.est.2c05781, 2022b.

Wolf, K., Bellouin, N., and Boucher, O.: Long-term upper-troposphere climatology of potential contrail occurrence over the Paris area derived from radiosonde observations, Atmos. Chem. Phys., 23, 287–309, https://doi.org/10.5194/acp-23-287-2023, 2023