1. ABOUT THE DATASET ------------ Title: An eddy tracking dataset for N512-12, N216-12 and N216-025 model configurations of HadGEM3-GC3.1 Creator(s): Sophia Moreton [1], Malcolm Roberts [2] Organisation(s): University of Reading [1], UK Met Office Hadley Centre [2] Rights-holder(s): Univeristy of Reading and Met Office Publication Year: 2021 Description: Closed coherent mesoscale eddies are identified and tracked daily in the global ocean for 20 years from sea surface height (SSH) using an eddy tracking algorithm, described by Moreton et al., 2020. The dataset provided here supplies the properties associated with each eddy: the latitude, longitude, radius, amplitude, number of days the eddy is tracked for and model time. Eddies are tracked in three coupled climate model HadGEM3-GC3.1 configurations: N512-12, N216-12 and N216-12. The original data from the corresponding fields (e.g. air or sea surface temperature) situated at each eddy snapshot, for each model configuration, can be found here: N216_12: Roberts, M.(2017a). MOHC HadGEM3-GC31-MH model output prepared for CMIP6 HighResMIP. Version 20190901. doi: https://doi.org/10.22033/ESGF/469CMIP6.1762470 N216_025: Roberts, M.(2017b). MOHC HadGEM3-GC31-MM model output prepared for CMIP6 HighResMIP Version 20190901. Retrieved from https://doi.org/47210.22033/ESGF/CMIP6.1902 doi: 10.22033/ESGF/CMIP6.1902473 N512_12: Roberts, M.(2018). MOHC HadGEM3-GC31-HH model output prepared for CMIP6 HighResMIP Version 20190901. Retrieved from https://doi.org/10.22033/475ESGF/CMIP6.445 doi: 10.22033/ESGF/CMIP6.445 Cite as: Moreton S. M. and Roberts M. (2021): An eddy tracking dataset for N512-12, N216-12 and N216-025 model configurations of HadGEM3-GC3.1. University of Reading. Dataset. DOI: http://dx.doi.org/10.17864/1947.283. https://researchdata.reading.ac.uk/id/eprint/283 Related publication: Moreton S., Ferreira D., Roberts M. and Hewitt H. (2021): Air-sea Turbulent Heat Flux Feedback over Mesoscale Eddies, Geophysical Research Letters (Submitted) Contact: s.moreton@pgr.reading.ac.uk 2. TERMS OF USE ----------------- Copyright 2021 University of Reading and Met Office (Crown copyright). This dataset is licensed under a Creative Commons Attribution 4.0 International Licence: https://creativecommons.org/licenses/by/4.0/. 3. PROJECT AND FUNDING INFORMATION ------------ Title: Air-sea exchanges at the oceanic mesoscale: a driver of ocean circulation ? Dates: September 2016. Funding organisation: NERC CASE Studentship, UK and the Met Office CASE studentship, UK. Malcolm Roberts is supported by the Joint UK BEIS/Defra Met Office Hadley Centre Climate Programme (GA01101) and acknowledges funding received from the European Commission under Grant Agreement 641727 (PRIMAVERA project) of the Horizon 2020 research programme. Grant no.: NE/N008448/1 for NERC CASE Studentship 4. CONTENTS ------------ File listing Pickle files of the tracked eddy properties over 20 years for each model configuration as named below. 'anti' refers to anti-cyclonic eddies and 'cyc' refers to cyclonic eddies. N216_12_tracked_eddies_20yrs_anti.pckl N216_12_tracked_eddies_20yrs_cyc.pckl N216_025_tracked_eddies_20yrs_anti.pckl N216_025_tracked_eddies_20yrs_cyc.pckl N512_12_tracked_eddies_20yrs_anti.pckl N512_12_tracked_eddies_20yrs_cyc.pckl Files were made using Python2.7 software. How to open the pickle files using Python: with open('N216_025_tracked_eddies_20yrs_anti.pckl', "rb") as f: ...: time_a, lat_a, lon_a, L_a, A_a, n_a = pickle.load(f) with open('N216_025_tracked_eddies_20yrs_cyc.pckl', "rb") as f: ...: time_c, lat_c, lon_c, L_c, A_c, n_c = pickle.load(f) where 'N216_025' is replaced with either 'N216_12' or 'N512_12' for each model configuration. In the example given '_a' refers to anti-cyclonic eddies, and '_c' refers to cyclonic eddies. List of the variables: 'time': days since 1950. The total time is 20 years where 1 year = 360 days. 'lat' : Latitude (degrees) 'lon' : Longitude (degrees) 'L' : Effective eddy radius (km) 'A' : Eddy amplitude (cm) 'n' : The days an eddy is tracked for. Eddies have to last longer than 6 days to be saved (set by the algorithm). The birth of each isolated eddy is given by n=1. For example, eddy 1 is tracked for 6 days and eddy 2 is tracked for 8 days: 1,2,3,4,5,6,1,2,3,4,5,6,7,8,1,2,... etc. 5. METHODS -------------------------- Using the 'pickle' module in Python, the dataset was generated to combine eddy properties from the eddy tracking algorithm output, described by Moreton et al., 2020 (full reference below). The 20-year dataset is global and the data was collected in 2016-2019. Both anti-cyclonic and cyclonic eddies were tracked separately, and the Northern Hemisphere was tracked separately to the Southern Hemisphere, then combined. Eddies with lifetimes shorter than 6 days are removed from the dataset. The full reference for details of the eddy tracking algorithm is: Moreton, S. M., Ferreira, D., Roberts, M., & Hewitt, H.(2020). Evaluating surface eddy properties in coupled climate simulations with ‘eddy-present’ and ‘eddy-rich’ ocean resolution. Ocean Modelling, 147. doi:45210.1016/j.ocemod.2020.101567