20CR data download and access

We are going to use monthly averaged surface variables from 20CRv3.

Four variables:

• TMP2m

• SST

• PRMSL

• PRATE

We can download all this from the Ensemble gateway at NERSC. Note that 20CRv3 is an ensemble product - for each month there are 80 ensemble members. We want them all - we can use them to estimate the uncertainty in the reanalysis.

• Script to do the whole download (about 180Gb, will take many hours). Only downloads data where it is not already on disc.

• Script to download a year of TWCR data.

Having downloaded the data, we need to use it. So we need some convenience functions to access the data.

• Functions to access downloaded 20CR data.

We also want one additional variable - the monthly standard deviation of PRMSL. This isn’t available as monthly data, so we need to download the hourly PRMSL and calculate the monthly sd.

• Script to do the whole hourly PRMSL download (about 5Tb, will take *many* hours).

• Script to download a year of hourly PRMSL.

• Script to calculate the monthly sd of PRMSL from the hourly data.