Data provided by UKESM1 Hindcast simulations for the North Atlantic Climate System Integrated Study (ACSIS) ====================================================== Three UKESM1 hindcasts have been performed in support of the North Atlantic Climate System Integrated Study (ACSIS). Data is provided as raw model output in Met Office PP (32-bit) format that can be read by the Iris (https://scitools-iris.readthedocs.io/en/stable/) or cf-python (https://ncas-cms.github.io/cf-python/) libraries. This is global data at N96eL85 resolution (1.875 x 1.25, 85 model levels up to 85km). Simulations were performed on the Monsoon2 HPC. The following fields are contained in the dataset: O3, NO, NO2, CO, CH4, 4x Stratospheric O3 tracers, and 30x idealised tracers emitted from various locations (15 with a 5-day e-folding lifetime, and 15 with a 30-day e-folding lifetime). Data is provided in mass mixing ratio (kg species/kg air). One simulation is a UKESM1.0 configuration at UM version 11.5 with additional diagnostics added and "nudged" to ERA-Interim reanalyses for 1981-2014 (u-bv711 and u-bw316) and continued using SSP3-7.0 forcings to 2019 (u-by117). One simulation is a UKESM1.0 configuration at UM version 11.5 with additional diagnostics added and "nudged" to ERA-5 reanalyses for 1982-2014 (u-bw784) and continued using SSP3-7.0 forcings to 2020 (u-by803). The bugfix documented in Ranjithkumar et al. 2021 has been applied (DOI:10.5194/acp-21-4979-2021). One simulation is a UKESM-StratTrop configuration with stratospheric ozone improvements at UM version 11.5 with additional diagnostics and "nudged" to ERA-5 reanalyses for 1982-2014 (u-bv828 and u-bx320) and continued using SSP3-7.0 forcings to 2020 (u-by808). The bugfix documented in Ranjithkumar et al. 2021 has been applied (DOI:10.5194/acp-21-4979-2021). Full dataset on the Met Office MASS tape archive, with diagnostics given in the file "ACSIS_diagnostics_table.txt". Diagnostics presented in this dataset are specified in the file "Selected_Diagnositcs.txt" and described below. The following fields are provided Species | STASH | Conversion | Notes | code | factor | -------------------------------------------------------------------------------- O3 | 34001 | 1.657 | NO | 34002 | 1.036 | NO2 | 34996 | 1.588 | CO | 34009 | 0.9665 | CH4 | 34010 | 0.5523 | O3S_PV | 34026 | 1.657 | O3 in the stratosphere using PV tropopause O3S_WMO | 34251 | 1.657 | O3 in the stratosphere using WMO tropopause O3SC_PV | 34252 | 1.657 | 1.0ppmv in the stratosphere using PV tropopause O3SC_WMO | 34253 | 1.657 | 1.0ppmv in the stratosphere using WMO tropopause IDT1 | 34461 | 1.0000 | 5-day e-folding lifetime Global IDT2 | 34462 | 1.0000 | 30-day e-folding lifetime Global IDT3 | 34463 | 1.0000 | 5-day e-folding lifetime Northern India IDT4 | 34464 | 1.0000 | 30-day e-folding lifetime Northern India IDT5 | 34465 | 1.0000 | 5-day e-folding lifetime Southern India IDT6 | 34466 | 1.0000 | 30-day e-folding lifetime Southern India IDT7 | 34467 | 1.0000 | 5-day e-folding lifetime Indian Ocean IDT8 | 34468 | 1.0000 | 30-day e-folding lifetime Indian Ocean IDT9 | 34469 | 1.0000 | 5-day e-folding lifetime Northern China IDT10 | 34470 | 1.0000 | 30-day e-folding lifetime Northern China IDT11 | 34471 | 1.0000 | 5-day e-folding lifetime Southern China IDT12 | 34472 | 1.0000 | 30-day e-folding lifetime Southern China IDT13 | 34473 | 1.0000 | 5-day e-folding lifetime Maritime Continent IDT14 | 34474 | 1.0000 | 30-day e-folding lifetime Maritime Continent IDT15 | 34475 | 1.0000 | 5-day e-folding lifetime West Pacific IDT16 | 34476 | 1.0000 | 30-day e-folding lifetime West Pacific IDT17 | 34477 | 1.0000 | 5-day e-folding lifetime East Pacific IDT18 | 34478 | 1.0000 | 30-day e-folding lifetime East Pacific IDT19 | 34479 | 1.0000 | 5-day e-folding lifetime Continental US IDT20 | 34480 | 1.0000 | 30-day e-folding lifetime Continental US IDT21 | 34481 | 1.0000 | 5-day e-folding lifetime South America IDT22 | 34482 | 1.0000 | 30-day e-folding lifetime South America IDT23 | 34483 | 1.0000 | 5-day e-folding lifetime Europe IDT24 | 34484 | 1.0000 | 30-day e-folding lifetime Europe IDT25 | 34485 | 1.0000 | 5-day e-folding lifetime North Africa IDT26 | 34486 | 1.0000 | 30-day e-folding lifetime North Africa IDT27 | 34487 | 1.0000 | 5-day e-folding lifetime Central Africa IDT28 | 34488 | 1.0000 | 30-day e-folding lifetime Central Africa IDT29 | 34489 | 1.0000 | 5-day e-folding lifetime Southern Africa IDT30 | 34490 | 1.0000 | 30-day e-folding lifetime Southern Africa The emissions file used by the simulations for the IDT tracers, "IDT_combined_emiss_flex_v2.nc", is also provided. The e-folding lifetime and region for each tracer are given above. The conversion factor from the provided mass-mixing ratio to mole fraction is listed. The data should be DIVIDED by this value to give the field in mole fraction. The 4x O3S tracers use two different tropopause definitions: * The "PV" tropopause uses a 2PV+380K surface as defined in Hoerling, Schaack and Lenzen, 1993 (DOI:10.1175/1520-0493(1993)121<0162:AGAOSE>2.0.CO;2). * The "WMO" tropopauses used the WMO Lapse Rate tropopause definition, which is the lowest level at which the lapse rate decreases to 2 K/km or less. World Meteorological Organization: Definition of the tropopause, Bulletin of the World Meteorological Organization, 6, 136–137, 1957.  Above these tropopause, the concentrations are either the model simulated ozone (O3S_PV and O3S_WMO) or a constant 1.0ppmv (O3SC_PV and O3SC_WMO). Nathan Luke Abraham 2024-01-29 National Centre for Atmospheric Science, UK Yusuf Hamied Department of Chemistry, University of Cambridge, UK