This README.txt file was generated on 20180605 by Ruza F Ivanovic

**DUE TO SIZE THE ZIP FILES ARE SPLIT INTO SMALLER ARCHIVE PARTS**

It is important to note that with a “split” archive the individual split files are not valid on their own (i.e. as smaller stand-alone archives). They are only valid when combined together to form a single large archive. 

Linux - there are generic commands and utilities which facilitate the production of split archives and more general ones to split any type of file into smaller parts. There are similar commands and utilities to join split files to form the original, single file. 

Windows - the 7-zip utility is particularly useful since, in addition to supporting all popular file archive formats, it also supports splitting an archive into smaller parts, and extracting all files from a “split” archive. 


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GENERAL INFORMATION

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1. TITLE OF DATASET

Climate model data presented in “Climatic effect of Antarctic meltwater overwhelmed by concurrent Northern hemispheric melt"


2. AUTHOR INFORMATION

   Principal Investigator Contact Information
	   Name: Ruza F. Ivanovic	
           Institution: University of Leeds
           Email: r.ivanovic@leeds.ac.uk
	   ORCID: orcid.org/0000-0002-7805-6018

   Co-investigator Contact Information
           Name: Lauren J Gregoire
           Institution: University of Leeds
           Email: l.j.gregoire@leeds.ac.uk

   Co-investigator Contact Information
           Name: Andrew D Wickert
           Institution: University of Minnesota
           Email: awickert@umn.edu


3. HOW TO CITE THIS DATASET / ASSOCIATED PUBLICATION

Please cite the publication in which these data are presented:
Ivanovic, R. F., Gregoire, L. J., Wickert, A. D., & Burke, A. (2018). Climatic effect of Antarctic meltwater overwhelmed by concurrent Northern hemispheric melt. Geophysical Research Letters. DOI: 10.1029/2018GL077623


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DATA & FILE OVERVIEW

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The climate model results were produced using HadCM3 (Unified Model version 4.5) MOSES2.1 with dynamic TRIFFID. Each simulation has a unique 5-letter identifier, which can also be used to access the simulation on the puma.nerc.ac.uk facility.


1. LIST OF SIMULATIONS

This dataset contains nine HadCM3 climate simulations for which the input boundary conditions (e.g. greenhouse gases, orbit, geography) have been set to 15.0 thousand years BP (ka). The simulations are forced with a 'background' ice sheet meltwater discharge and freshwater representing four possible Meltwater Pulse 1a scenarios. See the associated publication for a detailed description of the background discharge and four meltwater pulse scenarios, including an explanation of how they were derived. 

Note that each of the four scenarios begins with the 'background' simulation, and therefore the first 525 years of each scenario are identical (i.e. before the meltwater pulses begin). Then, each scenario consists of two sequential simulations: a meltwater pulse (scenario-simulationA) and a return to background conditions (scenario-simulationB). Thus, to look at each scenario in full, concatenate background, scenario-simulationA and scenario-simulationB.

Corresponding to the associated publication (above), the simulations are labelled as follows: 

- background: teqjb
- hiN_loS:
     scenario-simulationA: teqjc
     scenario-simulationB: teqjg
- hiS_loN: 
     scenario-simulationA: teqjd
     scenario-simulationB: teqjh
- hiN_leads_loS: 
     scenario-simulationA: teqje
     scenario-simulationB: teqji
- hiS_leads_loN: 
     scenario-simulationA: teqjf
     scenario-simulationB: teqjj


2. FILE STRUCTURE

There is one zip file per scenario ('background', 'hiN_loS', 'hiS_loN', 'hiN_leads_loS', 'hiS_leads_loN'), which contains the following structure of subdirectories: 

 {scenario}.zip
   |-scenario 
       |-freshwater_forcing
       |-output_time-series

 where: {scenario} is: 'background', 'hiN_loS', 'hiS_loN', 'hiN_leads_loS', or 'hiS_leads_loN'.

Within each of the sub-directories are files beginning with '{expt}.', where {expt} is: 'teqj[bcdefghij]', as per the labelling above.


3. FRESHWATER FORCING FILES

The freshwater forcing fields are contained in directories {scenario}/freshwater_forcing/

The files are:
{expt}.qrparm.wfix.nc

  Where {expt} is 'teqj[bcdefghij]', as above.

  This contains the freshwater forcing to the ocean surface (kg/m2/s). 
  (Note that this includes the standard freshwater forcing from iceberg calving and melting, as present in the pre-industrial.)
  
  For background and scenario-simulationB, the forcing is fixed in time. For scenario-simulationA, the forcing is transient. 
  
  The forcing file for scenario-simulationA has more timesteps than the simulation, and it overlaps with scenario-simulationB forcing. 
  When the forcing becomes constant (i.e. when the forcing file returns to background, and the output time-series runs out), switch to the forcing for scenario-simulationB.


4. OUTPUT TIME-SERIES FILES

 In directories {scenario}/output_time-series

 The files have the following naming convention:  
  {expt}a.variable.timestep.nc 

 Where:
  {expt} is 'teqj[bcdefghij]', as above. 
  {variable} is an identified for each specific variable (see section, 5 below).
  {timestep} is the temporal resolution of the output, either 'annual' or 'monthly'.


5. VARIABLES IN THE OUTPUT_TIME-SERIES FILES

 For each simulation, each {variable} is as follows:
  - evap2: total evapotranspiration (kg m-2)
  - iceconc: sea ice concentration (0-1; where 0 is none and 1 is total cover)
  - icedepth: sea ice depth (m)
  - merid: meridional overturning files for Atlantic, Pacific, Indian and Global Ocean basins (Sv)
  - mslp: air pressure at sea level (Pa)
  - oceanmixedpf: ocean mixed layer depth (m)
  - oceansalipf01: ocean salinity in ocean level 1 ((psu-35)/1000)
  - oceansalipg: ocean salinity at all depths ((psu-35)/1000)
  - oceantemppf01: ocean potential temperature in ocean level 1 (deg C)
  - oceantemppg: ocean potential temperature at all depths (deg C) 
  - oceanuvelpf01: surface ocean zonal (u) component velocity (cm s-1 towards E)
  - oceanuvelpg: ocean zonal (u) component velocity at all depths (cm s-1 towards E)
  - oceanvvelpf01: surface ocean meridional (v) component velocity (cm s-1 towards N)
  - oceanvvelpg: ocean meridional (v) component velocity at all depths (cm s-1 towards N)
  - precip: monthly total precipitation (kg m-2)
  - streamFnpf01: horizontal streamfunction (cm3 s-1)
  - temp2m: air temperature at 1.5 m above the surface (deg K)
  - u10m: westerly (u) component winds at 10 metres (m s-1, towards E)
  - u200: westerly (u) component winds at 200 mbar (m s-1, towards E)
  - u850: westerly (u) component winds at 850 mbar (m s-1, towards E)
  - v10m: southerly (v) component winds at 10 metres (m s-1, towards N)
  - v200: southerly (v) component winds at 200 mbar (m s-1, towards N)
  - v850: southerly (v) component winds at 850 mbar (m s-1, towards N)
  - vegfrac: fractional covering of functional types (0-1; where 0 is none and 1 is total cover). [z] levels are: 1 = Broadleaf, 2 = Needleleaf, 3 = C3 Grasses, 4 = C4 Grasses, 5 = Shrub, 6 = Urban, 7 = Lakes, 8 = Bare Soil, 9 = Ice
  - z500: geopotential height at 500 mbar (m)


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METHODOLOGICAL INFORMATION

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1. DESCRIPTION OF THE MODEL USED TO GENERATE THE DATA

The data was generated using the Met Office Hadley Centre Coupled Model version 3 (HadCM3) ocean-atmosphere-vegetation general circulation model. The atmosphere has a regular latitude-longitude grid of 2.5° × 3.75° resolution and 19 hybrid sigma-pressure coordinate layers, from the surface up to ~10 hPa. The ocean has a horizontal resolution of 1.25° × 1.25° with 20 vertical layers. The land-surface shceme is MOSES 2.1, and the model has dynamic vegetation (TRIFFID). See the reference publication (cited above) for more details. 


2. METHODS FOR PROCESSING THE DATA

Raw model output (saved at monthly and annual intervals, as described above) was concatenated sequentially to create the timeseries provided in this dataset. Running means can be calcualted from these data, or excerpts can be extracted in order to examine climatological means.


3. SOFTWARE-SPECIFIC INFORMATION NEEDED TO INTERPRET THE DATA

The data is provided in Netcdf-3 classic format. This format can be read and plotted to produce maps and other types of plots using software such as Panoply, Ferret, NCL, python, Matlab, IDL...