README on GO dataset V29

Chris Finlay 8.4.2019

- Derived from BGS checked Hourly means 1997 to December 2018 taken from  

ftp://ftp.nerc-murchison.ac.uk/geomag/Swarm/AUX_OBS/hour/

Robust 4 monthly means from HMV, after subtracting CM4 SQ preds and CHAOS-6-x7 ext model, with input from RC index RC_1997-2019_Feb_v3.dat.  See Olsen et al. (2014) for details. 

Note these are different from previous version as robust means are computed in 4 month bins, not 1 month bins.

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In folder 4monthlyRM_V29:
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Basic file 4 monthly robust means file: GR_OBS_RMM_MF_less_bias_V29_4month.10

This is with the estimated crustal bias removed, calculated by median residual from CHAOS for each component at each obs.

Associated diagonal covariance matrix, derived from covariances from detrended residuals from CHAOS core field, are found in

GR_OBS_RMM_MF_COV_V29_4month.10

SV estimates come from annual differences of the 4 monthly RMM:

GR_OBS_RMM_SV_V29_4month.10

With covariances computed in a similar way and provided in

GR_OBS_RMM_SV_COV_V29_4month.10

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In directory 4monthlyRM_nomag_V29:
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Same but without the magnetospheric field correction from CHAOS applied



