Climate Indices of Air Temperature and Precipitation: HadEX2 and GHCNDEX
Topics
- Access
- Description
- Parameters
- Coverage, spatial and temporal resolution
- Data quality
- Contact person
- References
- Data citation and License
Access
UNRESTRICTED:
RESTRICTED: This link to the data set is only available for a restricted user group. The data set is only accessible in CEN/MPI net or accessible from external nets with a customer account. Please contact ICDC if you would like to access this data from outside the network.
- View data at LAS: HADEX2 | GHCNDEX
- HadEX Data access via file system: /data/icdc/climate_indices/hadex2/
- GHCNDEX Data access via file system: /data/icdc/climate_indices/ghcndex/
Description
To better identify significant extreme events and changes in extensive data from temperature and precipitation measurements, the CCI/WCRP/JCOMM Expert Team on Climate Change Detection and Indices (ETCCDI) has defined 27 indices, all derived from daily temperature and precipitation data , Using the ClimDex software, two data sets with climate indices were calculated from different raw data sets and published at the CLIMDEX Website (see references).
The standardisation of these indices allows researchers to compare results across time periods, regions and source datasets. These indices are a standardized set that allows researchers to compare results across different time periods, regions, and raw datasets. Two resulting records are presented below and are available internally at ICDC, they were calculated from quality-controlled, non-homogenized, station data and brought to regular grids using different methods. More detailed descriptions of these indices with information about their calculation:
HadEX2 - global gridded climate extremes indices
HadEX2 is a global data set of climate extremes on land, which was derived from quality-checked daily data from more than 7000 temperature stations and more than 11000 precipitation stations with the help of the software "RClimDex". The raw data on which the calculation is based partly come from sources that are not public. In most cases, raw data has been carefully checked for quality and homogeneity by researchers in the country of origin. The climate indices are calculated for each station and then interpolated to a regular grid using a modified version of the Shepard algorithm "angular distance weighting" (ADW). The data set consists of 31 temperature and precipitation indices in a grid of 2.5 ° x 3.75 ° for the period from 1901 to 2010. The base period for calculations of for example percentiles was 1961–1990. There are annual and, for some indices, monthly values that are derived from the daily station data. All details are described in the reference given below.
GHCNDEX - Extreme climate indices from global long-term station data
GHCNDEX is a global data set of 26 climate indices over land on a regular 2.5 ° × 2.5 ° grid that starts in 1951 and is ongoing, that was built from the analysis of long-term stations from the Global Historical Climatology Network (GHCN)-Daily data set (see references) with annually values, for some indices also monthly is available. This data set is a monitoring product, which means that the GHCNDEX is regularly updated with new observations. In some regions there are no data available in recent years, so the data set has some gaps in these regions. All raw data are publicly available and subjected to quality control prior to calculation but not homogenized. The indices were calculated for all stations before the results were interpolated onto the grid. The documents given in the references contain a precise description of the procedure.
Last update of data set at ICDC:
Parameters
| Name | GHCNDEX | HadEX2 |
|---|---|---|
| Monthly maximum of 1-day and consecutive 5-day precipitation (Rx1day, Rx5day) | annual, monthly | annual, monthly |
| Simple precipitation intensity index (SDII) | annual | annual |
| Annual number of days exceeding a certain precipitation value (R10mm, R20mm) | annual | annual |
| Maximum length of dry spell (CDD) | annual | annual |
| Maximum length of wet spell (CWD) | annual | annual |
| Annual total precipitation exceeds a threshold (percentile) (R95p, R99p) | annual | annual |
| Annual total rainfall in rainy days (PRCPTOT) | annual | annual |
| Number of frost and ice days (FD, ID) | annual | annual |
| Number of summer days and tropical nights (SU, TR) | annual | annual |
| Extreme temperature values during a specific period (TXx, TNx, TXn, TNn) | annual, monthly | annual, monthly |
| Exceeding specific limits (Percentile) (TN10p, TN90p, TX10p, TX90p) | annual, monthly | annual, monthly |
| Daily temperature range (DTR) | annual, monthly | annual, monthly |
| Warm and cold spell duration (WSDI, CSDI) | annual | annual |
| Growing season length (GSL) | annual | annual |
| Extreme temperature range (ETR), TXx – TNn | - | annual, monthly |
| Contribution from very wet days (R95pTOT,R99pTOT), 100 * R95p / PRCPTOT | - | annual, monthly |
Coverage, spatial and temporal resolution
Period and temporal resolution:
- GHCNDEX: 1951 - ongoing
- HadEX2: 1901 - 2010
- annual, some parmeters monthly as well
Coverage and spatial resolution:
- Global
- GHCNDEX: 2.5 ° × 2.5 ° grid
- HadEX2: 2.5 ° x 3.75 ° grid
Format:
- NetCDF
Data quality
The quality can not be better than the quality of the measured data. Please see websites of the data sets for quality informations.
Contact
Annika Jahnke-Bornemann
ICDC / CEN / University of Hamburg
E-Mail: annika.jahnke-bornemann"AT"uni-hamburg.de
References
Literature:
- Donat, M. G., L. V. Alexander, H. Yang, I. Durre, R. Vose, R. J. H. Dunn, K. M. Willett, E. Aguilar, M. Brunet, J. Caesar, B. Hewitson, C. Jack, A. M. G. Klein Tank, A. C. Kruger, J. Marengo, T. C. Peterson, M. Renom, C. Oria Rojas, M. Rusticucci, J. Salinger, A. S. Elrayah, S. S. Sekele, A. K. Srivastava, B. Trewin, C. Villarroel, L. A. Vincent, P. Zhai, X. Zhang and S. Kitching. 2013a. Updated analyses of temperature and precipitation extreme indices since the beginning of the twentieth century: The HadEX2 dataset, J. Geophys. Res. Atmos., 118, 2098–2118. doi: 10.1002/jgrd.50150.
- Donat, M.G., L.V. Alexander, H. Yang, I. Durre, R. Vose, J. Caesar. 2013b. Global Land-Based Datasets for Monitoring Climatic Extremes, Bull. Amer. Meteor. Soc., 94, 997–1006. doi: 10.1175/BAMS-D-12-00109.1.
Websites:
- CLIMDEX Website, https://www.climdex.org/
- Global Historical Climatology Network (GHCN), https://www.ncdc.noaa.gov/data-access/land-based-station-data/land-based-datasets/global-historical-climatology-network-ghcn
- ETCCDI Climate Change Indices, http://etccdi.pacificclimate.org/
Data citation, License, and Acknowledgments
Please cite the HeadEX2 data as follows:
Donat, M. G., L. V. Alexander, H. Yang, I. Durre, R. Vose, R. J. H. Dunn, K. M. Willett, E. Aguilar, M. Brunet, J. Caesar, B. Hewitson, C. Jack, A. M. G. Klein Tank, A. C. Kruger, J. Marengo, T. C. Peterson, M. Renom, C. Oria Rojas, M. Rusticucci, J. Salinger, A. S. Elrayah, S. S. Sekele, A. K. Srivastava, B. Trewin, C. Villarroel, L. A. Vincent, P. Zhai, X. Zhang and S. Kitching. 2013a. Updated analyses of temperature and precipitation extreme indices since the beginning of the twentieth century: The HadEX2 dataset, J. Geophys. Res. Atmos., 118, 2098–2118. doi: 10.1002/jgrd.50150.
Please cite the GHCNDEX data as follows:
Donat, M.G., L.V. Alexander, H. Yang, I. Durre, R. Vose, J. Caesar. 2013b. Global Land-Based Datasets for Monitoring Climatic Extremes, Bull. Amer. Meteor. Soc., 94, 997–1006. doi: 10.1175/BAMS-D-12-00109.1.
and with the following acknowledgments:
Thanks to ICDC, CEN, University of Hamburg for data support.
License
The GHCNDEX and the HeadEX2 data was published under the Creative Commons Attribution 4.0 license.