1. PROJECT ------------ Title: The response of Northern Hemisphere polar lows to climate change in a 25 km high-resolution global climate model. Publication Year: 2022 The work described in this paper has received funding from the European Union's Horizon 2020 Research and Innovation programme through Grant agreement no. 727862 APPLICATE. 2. DATASET and METHOD ------------ Title: Tracks of polar lows over the Northern Hemisphere in present and future HadGEM3-GA3 N512 simulations. Creator(s): Hélène Bresson [1], Kevin Hodges [2], Giuseppe Zappa [1,*] Contributor(s): Reinhard Schiemann [2] Organisation(s): University of Reading [1], National Centre for Atmospheric Science [2] *: now at National Research Council of Italy, Institute of Atmospheric Sciences and Climate Rights-holder(s): Hélène Bresson, University of Reading and National Centre for Atmospheric Science Related publication: Bresson, H., K. I. Hodges, L. C. Shaffrey, G. Zappa, R. Schiemann, 2022, JGR Atmospheres: The response of Northern Hemisphere polar lows to climate change in a 25 km high-resolution global climate model (accepted) Contact: h.bresson@reading.ac.uk/hbresson@orange.fr Cite as: Bresson, H., Hodges, K. and Zappa G. (2022): Tracks of Polar lows over the Northern Hemisphere with the HadGEM3-GA3 N512 present and future climate simulations. University of Reading. Dataset. DOI: https://doi.org/10.17864/1947.000299. Description: Tracks of Polar lows over the Northern Hemisphere for both present and future (RCP8.5) climate scenarios from the HadGEM3-GA3 N512 simulations. The original data come from the HadGEM3-GA3 N512 global climate model simulations from the UK on PRACE weather-resolving Simulations of Climate for globAL Environmental risk (UPSCALE) high-resolution simulations (Mizielinski et al., 2014; http://proj.badc.rl.ac.uk/upscale/wiki). For this study, three ensemble members for both historical (1985-2010) and future (2085-2110) climate conditions at 25 km (N512) horizontal resolution. Those data can be accessed by contacting: met-upscale@lists.reading.ac.uk The tracking of polar lows has been performed with the TRACK algorithm (Hodges, 1994, 1995, 1999; https://gitlab.act.reading.ac.uk/track/track, version 1.4.7). The methodology for the tracking and identification scheme is presented in Zappa et al. (2014). More information on the dataset and method can be found in: Bresson, H. M. E. (2019) Polar Lows: their climatology, interaction with the ocean and response to climate change. PhD thesis, University of Reading 3. TERMS OF USE ----------------- Copyright 2022 Hélène Bresson, University of Reading and National Centre for Atmospheric Science. This dataset is licensed under a Creative Commons Attribution 4.0 International Licence: https://creativecommons.org/licenses/by/4.0/. 4. CONTENTS ------------ The files are .txt files and can be opened and read with any text editor software (such as TextEdit, NotePad, EmEditor, etc.) or directly into the Terminal using text editor such as Vi, Vim, Emacs, etc (command example: "vi filename"). File listing Polar low tracks for the three historical (1985-2010) climate simulations: Track_N512HadGEM3GA3_Pres_xgxqe Track_N512HadGEM3GA3_Pres_xgxqf Track_N512HadGEM3GA3_Pres_xgxqg Polar low tracks for the three future (2085-2110) climate simulations: Track_N512HadGEM3GA3_Fut_xgxqk Track_N512HadGEM3GA3_Fut_xgxql Track_N512HadGEM3GA3_Fut_xgxqm All files contain 26 "years" of months from October to March (i.e. first year is October 1985 to March 1986). Files header: Total number of tracks, track ID and number of point (time step) for the polar low. List of the variables in column in files (column separator: "&"): First column : time step (every 6 hours, i.e. if the track has 2 points the polar low lasted 6 hours) Second column : longitude (degrees) Third column : latitude (degrees) Fourth column : vorticity (s-2) Fifth column : vorticity (s-2) at which all polar low identification criteria are satisfied Sixth column : temperature at 500 hPa (K) Seventh column : surface temperature (K) Eighth column : wind speed (m s-1) Example for "Tracks_HadGEM3GA3_N512_PresentClimate_simulations_xgxqe": TRACK_NUM 2426 ADD_FLD 4 4 &0000 TRACK_ID 1 POINT_NUM 5 6 214.066315 57.694340 6.255500e+00 & 0.000000e+00 & 2.399100e+02 & 2.840700e+02 & 1.469500e+01 & 7 214.535049 57.599117 8.310200e+00 & 8.310200e+00 & 2.398000e+02 & 2.841500e+02 & 1.695400e+01 & 8 214.287262 57.118607 7.044100e+00 & 0.000000e+00 & 2.397000e+02 & 2.843400e+02 & 1.808300e+01 & 9 215.937164 56.693275 6.094400e+00 & 0.000000e+00 & 2.396100e+02 & 2.844000e+02 & 1.595500e+01 & 10 215.170944 56.183659 4.830500e+00 & 0.000000e+00 & 2.401100e+02 & 2.841500e+02 & 1.734200e+01 & --> The present "xgxqe" simulation has 2426 tracks identified as polar low tracks, and the first polar low track has 5 time steps (lasted for 30 hours) which started on time step #6 (so on 2nd October 1985 12:00). 5. REFERENCES: -------------------------- Bresson, H. M. E. (2019) Polar Lows: their climatology, interaction with the ocean and response to climate change. PhD thesis, University of Reading, https://doi.org/10.48683/1926.00085072. Hodges, K. I. (1994). A general method for tracking analysis and its application to meteorological data. Monthly Weather Review, 122 (11), 2573-2586, https://doi.org/10.1175/1520-0493(1994)122<2573:AGMFTA>2.0.CO;2. Hodges, K. I. (1995). Feature tracking on the unit sphere. Monthly Weather Review, 123 (12), 3458-3465, https://doi.org/10.1175/1520-0493(1995)123<3458:FTOTUS>2.0.CO;2. Hodges, K. I. (1999). Adaptive constraints for feature tracking. Monthly Weather Review, 127 (6), 1362-1373, https://doi.org/10.1175/1520-0493(1999)127<1362:ACFFT>2.0.CO;2. Mizielinski, M. S., Roberts, M. J., Vidale, P. L., Schiemann, R., Demory, M.-E., Strachan, J., Edwards, T., Stephens, A., Lawrence, B. N., Pritchard, M., Chiu, P., Iwi, A., Churchill, J., del Cano Novales, C., Kettleborough, J., Roseblade, W., Selwood, P., Foster, M., Glover, M., and Malcolm, A.: High-resolution global climate modelling: the UPSCALE project, a large-simulation campaign, Geosci. Model Dev., 7, 1629–1640, https://doi.org/10.5194/gmd-7-1629-2014, 2014. Zappa, G., Shaffrey, L., & Hodges, K. (2014). Can polar lows be objectively identified and tracked in the ECMWF operational analysis and the era-interim reanalysis? Monthly Weather Review, 142, 2596-2608, https://doi.org/10.1175/MWR-D-14-00064.1.