Met Office Hadley Centre observations datasets
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HadISD online material - version

Please read the Geoscientific Instrumentation, Methods & Data Systems and Climate of the Past I and II papers before using the material presented here.

The netCDF headers are listed below with some information as to what they contain.

Field NameLong NameUnits
timeTimeHours since 1-1-1931 00:00UT
input_station_idPrimary source for timestep data
wind gustm/s
slpsea-level pressurehPa
past_sigwx1Past significant weather code
precip1_depthDepth of Precipitation from first ISD fieldmm
precip1_periodPrecipitation Accumulation Period for first ISD fieldhr
qc_flagsQuality control flags
flagged_valuesRemoved values (T, D, S, TC, LC, MC, HC, WS, WD)

Precipitation in HadISD: For users wishing to use the precipitation information available in HadISD, we ask them to take care and familiarise themselves with both the HadISD and the ISD documentation. The precip1_depth field derives from the first ISD precipitation field, and must be used with the precip1_period field, as the "1" in the name does not refer to hourly accumulations. Also, despite the time dimension being in hours, the precipitation accumulations may refer to longer time periods, detailed in precip1_period. Furthermore, we note here that the precipitation depths have not been quality controlled and users should confirm for themselves that the data are sufficiently free of erroneous measurements for their purposes (RJHD 26-February 2018).

The homogeneity information for this version is available here - the list of breaks and also some of the graphical outputs. The columns of the datafiles give the Station ID, the date of the change point, and two break magnitudes (one in the case of SLP). The first is from the monthly mean value, and the second is from the monthly mean diurnal range (temperature & dewpoint temperatures) or monthly mean daily maximum (wind speed). Missing values are denoted by -99.99. Please get in touch if there are any queries.

The inhomogeneity information has been calculated presuming the most recent period of a station is accurate and hence tranversing the timeseriers backwards in time. Therefore a negative in homogeneity value given indicates that prior to the month given, the data is at a lower value (so the adjustment required would be positive). Conversely, a positive vaue indicates that prior to the month given the data is at a higher value (a negative adjustment required).

DescriptionData fileNotes
Merged temperature inhomogeneitiesMergedBreaks_temperatures.dat
Merged dewpoint inhomogeneitiesMergedBreaks_dewpoints.dat
Merged SLP inhomogeneitiesMergedBreaks_slp.dat
Merged windspeeds inhomogeneitiesMergedBreaks_windspeeds.dat
And figures from the homogeneity assessment
Distribution - averagePHA_temperatures_average_distribution.pngPHA_dewpoints_average_distribution.pngPHA_slp_average_distribution.pngPHA_windspeeds_average_distribution.png
Distribution - DTRPHA_temperatures_dtr_distribution.pngPHA_dewpoints_dtr_distribution.png--
Distribution - max---PHA_windspeeds_max_distribution.png
Map - average - inhomogeneity sizebreak_size_map_temperatures_average.pngbreak_size_map_dewpoints_average.pngbreak_size_map_slp_average.pngbreak_size_map_windspeeds_average.png
Map - dtr - inhomogeneity sizebreak_size_map_temperatures_dtr.pngbreak_size_map_dewpoints_dtr.png--
Map - max - inhomogeneity size---break_size_map_windspeeds_max.png
Map - inhomogeneity numberbreak_number_map_temperatures.pngbreak_number_map_dewpoints.pngbreak_number_map_slp.pngbreak_number_map_windspeeds.png
Map - no inhomogeneitieszero_breaks_map_temperatures.pngzero_breaks_map_dewpoints.pngzero_breaks_map_slp.pngzero_breaks_map_windspeeds.png

A number of files and plots are linked below which were used or generated when creating HadISD.

DescriptionStation NumberData fileNotes
Station Lists
HadISD Station List8103hadisd_station_info_v202.txt1
HadISD Station Additions241hadisd_station_additions_v202.txt
HadISD Station Removals15hadisd_station_removals_v202.txt
Composite Stations2111final_mergers.txt2
User Identified erroneous data
Failure Rate Summaries
Number of stations with a failures from a certain test in percentage binsall_fails_summary_20180314.dat3
Test 3-letter code descriptortests_codes.txt

Failure Rate Plots
Duplicate monthsAllepspng
Odd ClusterTemperaturesepspng
Odd ClusterDew Pointsepspng
Odd ClusterSLPepspng
Odd ClusterWind Speedepspng
Frequent Value CheckTemperatureepspng
Frequent ValuesDew pointepspng
Frequent ValuesSLPepspng
Diurnal Cycle CheckAllepspng
Gap CheckTemperatureepspng
Gap CheckDew pointepspng
Gap CheckSLPepspng
Record CheckTemperatureepspng
Record CheckDew pointepspng
Record CheckSLPepspng
Record CheckWind speedepspng
Day StringsTemperatureepspng
Day StringsDew pointepspng
Day StringsSLPepspng
Day StringsWind speedepspng
Straight StringsTemperatureepspng
Straight StringsDew pointepspng
Straight StringsSLPepspng
Straight StringsWind speedepspng
Hour StringsTemperatureepspng
Hour StringsDew pointepspng
Hour StringsSLPepspng
Hour StringsWind speedepspng
All temperature stringsTemperatureepspng
All dewpoint stringsDew pointepspng
All SLP stringsSLPepspng
All wind stringsWind speedepspng
Climatological CheckTemperatureepspng
Climatological CheckDew pointepspng
Climatological CheckSLPepspng
Spike CheckTemperatureepspng
Spike CheckDew pointepspng
Spike CheckSLPepspng
Spike CheckWind speedepspng
SupersaturationDew pointepspng
Dew point depressionDew pointepspng
Dew point Cut OffDew pointepspng
Variance CheckTemperatureepspng
Variance CheckDew pointepspng
Variance ChecksSLPepspng
Variance ChecksWind speedepspng
Logical CheckWind speedepspng
Wind RoseWind speedepspng
Cloud TotalLow,Mid,High,Totalepspng
UnobservableHigh Cloudepspng
UnobservableLow Cloudepspng
UnobservableMid Cloudepspng
UnobservableTotal Cloudepspng
Full Low cloud checkMid & High Cloudepspng
Full Mid cloud checkHigh Cloudepspng
Negative cloud valueAll Cloudepspng
Neighbour OutlierTemperatureepspng
Neighbour OutlierDew pointepspng
Neighbour OutlierSLPepspng
Month clearedTemperatureepspng
Month clearedDew pointepspng
Month clearedSLPepspng
Month ClearedWind Speedepspng
Month clearedWind Directionepspng
Month clearedTotal cloudepspng
Month clearedHigh Cloudepspng
Month clearedMid Cloudepspng
Month clearedLow Cloudepspng
Month clearedCloud Baseepspng
AllDew pointepspng


[1] Station ID, latitude, longitude and elevation used.
[2] First ID in the line is the station ID used throughout the processing. The remainder are ones which were composited into this station record.
[3] Summary table in the paper was created from this file. And you will need the test_codes.txt file to interpret these outputs.