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 https://www.climdex.org/.
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.
Annual indices available at ICDC:
- Monthly maximum of 1-day and consecutive 5-day precipitation (Rx1day, Rx5day) (also monthly)
- Simple precipitation intensity index (SDII)
- Annual number of days exceeding a certain precipitation value (R10mm, R20mm)
- Maximum length of dry spell (CDD)
- Maximum length of wet spell (CWD)
- Annual total precipitation exceeds a threshold (percentile) (R95p, R99p)
- Annual total rainfall in rainy days (PRCPTOT)
- Number of frost and ice days (FD, ID)
- Number of summer days and tropical nights (SU, TR)
- Extreme temperature values during a specific period (TXx, TNx, TXn, TNn) (also monthly)
- Exceeding specific limits (Percentile) (TN10p, TN90p, TX10p, TX90p) (also monthly)
- Daily temperature range (DTR) (also monthly)
- Warm and cold spell duration (WSDI, CSDI)
- Growing season length (GSL)
- Extreme temperature range (ETR), TXx – TNn (also monthly)
- Contribution from very wet days (R95pTOT,R99pTOT), 100 * R95p / PRCPTOT
Citation
When using the dataset in a paper, please use the following citation:
- 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.
Data source
The data can be found in monthly and annual resolution through https://climdex.org/access/ or through ICDC:
- View data via LAS
- Data access via file system: /data/icdc/climate_indices/hadex2/
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 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.
Available annual indices:
- Monthly maximum of 1-day and consecutive 5-day precipitation (Rx1day, Rx5day) (also monthly)
- Simple precipitation intensity index (SDII)
- Annual number of days exceeding a certain precipitation value (R10mm, R20mm)
- Maximum length of dry spell (CDD)
- Maximum length of wet spell (CWD)
- Annual total precipitation exceeds a threshold (percentile) (R95p, R99p)
- Annual total rainfall in rainy days (PRCPTOT)
- Number of frost and ice days (FD, ID)
- Number of summer days and tropical nights (SU, TR)
- Extreme temperature values during a specific period (TXx, TNx, TXn, TNn) (also monthly)
- Exceeding specific limits (Percentile) (TN10p, TN90p, TX10p, TX90p) (also monthly)
- Daily temperature range (DTR) (also monthly)
- Warm and cold spell duration (WSDI, CSDI)
- Growing season length (GSL)
Citation
If you use this data set please cite 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.
Data source
Get the data with monthly or annual resolution from https://www.climdex.org/learn/datasets/ or from ICDC:
- View data via LAS
- Data access via file system: /data/icdc/climate_indices/ghcndex/
