Data

Data description

HadTH are available as monthly timeseries for radiosonde stations. Data are available on standard pressure levels (Surface, 1000, 850, 700, 500, 400, 300). All values are anomalies relative to the monthly 1981-2000 climatology. As documented in McCarthy et al. 2009 only the northern hemisphere have sufficient data for the homogenisation method.

Data are in binary format Netcdf files which are CF compliant (external link).

Data usage

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Audit Trail for HadTH

The process is documented in McCarthy et al. 2009 and summarised below with links to the data.

Source Data - HadTH0.0

The dataset is constructed from two datasets provided by the National Climatic Data Center in the U.S. These are the Integrated Global Radiosonde Archive (IGRA) provided by NCDC to Hadley Centre at the time of generation included data up to the year 2003. The dataset was further supplemented by an earlier product the Comprehensive Aerological Reference Dataset (CARDS, Eskridge et al. 1995, Bull. Amer. Meteor. Soc., 76, 1759-1775) for the period 1963-2001 inclusive. As stated in the manuscript this dataset is not suitable for assessing trends or variability in individual station records.

List of IGRA and CARD stations used in HadTH

HadTH0_0_day Normals - The unhomogenised 1981-2000 monthly climatologies from day launches.

HadTH0_0_night Normals - As above from night launches.

HadTH0.0	Temperature	Relative Humidity	Specific Humidity
Day Anomalies.	HadTH0_0_day_Tstation_data_record.nc.gz	HadTH0_0_day_RHstation_data_record.nc.gz	HadTH0_0_day_qstation_data_record.nc.gz
Night Anomalies.	HadTH0_0_night_Tstation_data_record.nc.gz	HadTH0_0_night_RHstation_data_record.nc.gz	HadTH0_0_night_qstation_data_record.nc.gz

Correct Sampling biases - HadTH1.0

The next step in HadTH removed known sampling biases resulting from missing "dry" and missing "cold" observations early in the record.

A list of stations for which daily humidity data were adjusted where low humidity values had been replaced with 19% relative humdity or dewpoint depression of -30degC.

Monthly means were also adjusted to account for missing humidity observations at low temperatures at many stations.

HadTH1_0_day Normals - The sampling bias corrected 1981-2000 monthly climatologies from day launches.

HadTH1_0_night Normals - As above from night launches.

HadTH1.0	Temperature	Relative Humidity	Specific Humidity
Day Anomalies.	HadTH1_0_day_Tstation_data_record.nc.gz	HadTH1_0_day_RHstation_data_record.nc.gz	HadTH1_0_day_qstation_data_record.nc.gz
Night Anomalies.	HadTH1_0_night_Tstation_data_record.nc.gz	HadTH1_0_night_RHstation_data_record.nc.gz	HadTH1_0_night_qstation_data_record.nc.gz

First guess of known breakpoints - HadTH1.1

A set of adjustments are created for known metadata events such as change of instrumentation and included in Appendix C of McCarthy et al. 2009.

HadTH1.1	Temperature	Relative Humidity	Specific Humidity
Day Anomalies.	HadTH1_1_day_Tstation_data_record.nc.gz	HadTH1_1_day_RHstation_data_record.nc.gz	HadTH1_1_day_qstation_data_record.nc.gz
Night Anomalies.	HadTH1_1_night_Tstation_data_record.nc.gz	HadTH1_1_night_RHstation_data_record.nc.gz	HadTH1_1_night_qstation_data_record.nc.gz

Homogenisation - HadTH1.2

The dataset is then homogenised to produce:

HadTH1.2	Temperature	Relative Humidity	Specific Humidity
Day Anomalies.	HadTH1_2_day_T_NH.nc.gz	HadTH1_2_day_RH_NH.nc.gz	HadTH1_2_day_q_NH.nc.gz
Night Anomalies.	HadTH1_2_night_T_NH.nc.gz	HadTH1_2_night_RH_NH.nc.gz	HadTH1_2_night_q_NH.nc.gz

Uncertainty - HadTH_Quarc

The homogenization method is conducted 100 times to produce an ensemble of reconstructions that can be used to quantify the methodological uncertainty.

QUARC - 100 realisations of station adjustments.

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