This is the 4.0.0.2017f version of the HadISDH land data. These data are provided by the Met Office Hadley Centre. This version spans 1/1/1973 to 31/12/2017. The data are monthly gridded (5 degree by 5 degree) fields. Products are available for temperature and six humidity variables: specific humidity (q), relative humidity (RH), dew point temperature (Td), wet bulb temperature (Tw), vapour pressure (e), dew point depression (DPD). Data are provided in either NetCDF or ASCII format. This version extends the 3.0.0.2016p version to the end of 2017 and constitutes a major update to HadISDH due to a change to using the 1981-2010 period as its climatological reference period both to make it more consistent with other monitoring products and to maximise station coverage now that it uses the larger station database of HadISD2. Users are advised to read the update document in the docs section for full details. This version now uses the 1981-2010 period as its climatological reference period both to make it more consistent with other monitoring products and to maximise station coverage now that it uses the larger station database of HadISD2. Additionally, there has been a small methodological change. Stations with large adjustments made during homogenisation are removed based on thresholds for q (>3g/kg), RH (>15%rh), T (>5degC) and Td (>5degC) rather than just T and Td. This results in 54 stations being removed as opposed to 29 last year. All other processing steps for HadISDH remain identical. The new version of HadISD2 (2.0.2.2017p) has pulled through some historical changes to stations which are passed on to HadISDH. This, and the additional year of data, results in small changes to station selection. The homogeneity adjustments differ slightly due to sensitivity to the addition and loss of stations, historical changes to stations previously included and the additional 12 months of data. To keep informed about updates, news and announcements follow the HadOBS team on twitter @metofficeHadOBS. For more detailed information e.g bug fixes, routine updates and other exploratory analysis, see the HadISDH blog: http://hadisdh.blogspot.co.uk/ References: When using the dataset in a paper you must cite the following papers (see Docs for link to the publications) and this dataset (using the "citable as" reference) : Willett, K. M., Dunn, R. J. H., Thorne, P. W., Bell, S., de Podesta, M., Parker, D. E., Jones, P. D., and Williams Jr., C. N.: HadISDH land surface multi-variable humidity and temperature record for climate monitoring, Clim. Past, 10, 1983-2006, doi:10.5194/cp-10-1983-2014, 2014. Smith, A., N. Lott, and R. Vose, 2011: The Integrated Surface Database: Recent Developments and Partnerships. Bulletin of the American Meteorological Society, 92, 704–708, doi:10.1175/2011BAMS3015.1 We strongly recommend that you read these papers before making use of the data, more detail on the dataset can be found in an earlier publication: Willett, K. M., Williams Jr., C. N., Dunn, R. J. H., Thorne, P. W., Bell, S., de Podesta, M., Jones, P. D., and Parker D. E., 2013: HadISDH: An updated land surface specific humidity product for climate monitoring. Climate of the Past, 9, 657-677, doi:10.5194/cp-9-657-2013.

This dataset contains surface layer meteorological measurements that were made during the Iceland Greenland Seas Project (IGP) field campaign from a variety of observation platforms, including several WeatherPack systems, RPG Hatpro Radiometer and a Windcube LIDAR. This dataset presents a quality controlled combination of observations from these instruments, as indicated by the data origin flags. Sea surface temperature was measured by the underway SBE38 bow temperature sensor for the majority of the cruise, with 2m CTD observations used to fill several short gaps where high frequency observations were available. Additionally these observations have been processed using the COARE 3.0a bulk aerodynamic flux algorithm to provide bulk variables at standard heights and estimated flux coefficients. Attached documentation on quality control methods and calibrations should be consulted before using these data. The Iceland Greenland seas Project (IGP) was an international project involving the UK, US a Norwegian research communities. The UK component was funded by NERC, under the Atmospheric Forcing of the Iceland Sea (AFIS) project (NE/N009754/1).

HadEX3 is a land-surface dataset of climate extremes indices available on a 1.875 x 1.25 longitude-latitude grid covering 1901-2018. These 29 indices have been developed by the World Meteorological Organization (WMO) Expert Team on Climate Change Detection and Indices (ETCCDI). Indices are available on an annual, and for some a monthly, basis. Some indices use a reference period to calculate thresholds, and for these, we provide versions using 1961-90 and 1981-2010. The indices are available in NetCDF files, with one index per file and separate files for annual and monthly values, as well as the different reference periods if appropriate. The codes used to create the dataset are available online, and a wide number of analysis plots are on the dataset homepage. For a detailed description of the methods behind the dataset, please see the paper in Details/Docs.

The European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-40 Re-Analysis Project consists of a number of climate datasets spanning the period mid-1957 to August 2002 using a consistent model. The data overlaps with the earlier ECMWF ERA-15 Re-analysis project (1979-1993). This dataset collection contains both initialised and uninitialised T106 spectral upper air data (approximately 1 degree resolution) on model levels and standard pressure levels. Corresponding surface parameters are held on a reduced Gaussian N80 grid. Regular 2.5 degree x 2.5 degree gridded data are also stored on standard pressure levels and at the surface.

To address the needs of the cryospheric science community, the SMMR-SSM/I, AVHRR and TOVS research teams collaborated to make it as easy as possible for the Polar Pathfinders and related data sets to be used together. The teams employed a common projection, the NSIDC Equal-Area Scalable Earth-Grid (EASE-Grid), file naming conventions and validation methods to develop consistently processed data sets that are easy to combine and contrast. The Polar Pathfinder Sampler CD-ROM is an innovative assemblage of atmospheric and surface measurements from all three Pathfinders. Included is a two-year period of daily merged Pathfinder data sets at 100 km-resolution, placed in a multidimensional structure known as the "P-Cube." In addition, samples of full-resolution Special Sensor Microwave Imager(SSM/I), TIROS Operational Vertical Sounder (TOVS) and Advanced Very High Resolution Radiometer (AVHRR) (both the 1.25 km and 5 km products) Polar Pathfinder data sets are included, also in Equal-Area Scalable Earth-Grid (EASE-Grid), making it easy to compare parameters at multiple resolutions. The new product provides data for a wide range of polar climate research applications, but is especially keyed to the needs of investigators dealing with large-scale atmospheric changes, surface heat and mass balance studies, and sea ice modelling. This dataset is public

The European Centre for Medium-Range Weather Forecasts (ECMWF) has provided global atmospheric analyses from its archive for many years. The ERA-15 Re-analysis project was devised in response to wishes expressed by many users for a data set generated by a modern, consistent, and invariant data assimilation system. The ERA-15 project produced a long time-series (January 1979 - February 1994) of consistent meteorological analyses using a single version of the ECMWF model. Dataset contains both initialised and uninitialised T106 spectral upper air data (approximately 1 degree resolution) on model levels and standard pressure levels. Corresponding surface parameters are held on a reduced gaussian N80 grid. Regular 2.5 degree x 2.5 degree gridded data is also stored on standard pressure levels and at the surface.

HadEX3 is a land-surface dataset of climate extremes indices available on a 1.875 x 1.25 longitude-latitude grid. These 29 indices have been developed by the World Meteorological Organization (WMO) Expert Team on Climate Change Detection and Indices (ETCCDI). Daily precipitation, as well as maximum and minimum temperature observations, are used to calculate these indices at each station. The daily data, as well as indices, have been supplied, quality controlled and combined to make a gridded set of NetCDF files covering 1901-2018 (inclusive). Spatial coverage is determined by the number of stations present at each time point as well as the spatial correlation structure between the stations for each index. The spatial coverage is lowest at the beginning of the dataset, rising until around 1960 where it plateaus, and then declines slightly after 2010. All indices are available as annual quantities, with a subset also available on a monthly basis. A number of the indices use a reference period to determine thresholds. For these, we provide two versions, one set using 1961-1990 and another using the more recent 1981-2010 (these reference periods have been indicated in the file name as either 'ref-6190' or 'ref-8110'). Version 3.0.2 was added due to a correction to the land-sea mask used. More details can be found in the HadEX3 blog under 'Details/Docs' tab.

Surface pressure, temperature and humidity data (PTU) were collected by a Vaisala WXT510 instrument located at the Natural Environment Research Council's (NERC) Mesosphere-Stratosphere-Troposphere (MST) Radar Facility, Capel Dewi, near Aberystwyth in West Wales. Rainfall rate data from this instrument are also available as a separate dataset within the MST Radar Facility dataset collection. The WXT-510 instrument at the site began operational recording in December 2007 and ceased in January 2015, subsequently being replaced by a Vaisala WXT-520 instrument. The WXT520 data are also available from CEDA as part of the MST Radar Facility's dataset collection. Independent surface meteorological data are also collected from a suite of instruments by a Campbell Scientific CR10 Climate Data Logger. These data are available as a separate dataset within the MST Radar Facility dataset collection.

Regularly gridded operational data at 1.125 degree resolution from 2000 to present containing the ongoing analyses and forecasts produced by the most recent ECMWF Integrated Forecasting System (IFS) model. The IFS is regularly updated as improvements are made to the model, computing facilities and observations used in data assimilation.

HadEX3 is a land-surface dataset of climate extremes indices available on a 1.875 x 1.25 longitude-latitude grid. These 29 indices have been developed by the World Meteorological Organization (WMO) Expert Team on Climate Change Detection and Indices (ETCCDI). Daily precipitation, as well as maximum and minimum temperature observations, are used to calculate these indices at each station. The daily data, as well as indices, have been supplied, quality controlled and combined to make a gridded set of NetCDF files covering 1901-2018 (inclusive). Spatial coverage is determined by the number of stations present at each time point as well as the spatial correlation structure between the stations for each index. The spatial coverage is lowest at the beginning of the dataset, rising until around 1960 where it plateaus, and then declines slightly after 2010. All indices are available as annual quantities, with a subset also available on a monthly basis. A number of the indices use a reference period to determine thresholds. For these, we provide two versions, one set using 1961-1990 and another using the more recent 1981-2010 (these reference periods have been indicated in the file name as either 'ref-6190' or 'ref-8110'). Version 3.0.3 was added due to an error in how the Rx1day and Rx5day data were being handled for one of the West African data sources. More details can be found in the HadEX3 blog under 'Details/Docs' tab.