\chapter{Introduction}

The Climate Data Operators ({\CDO}) software is a collection of operators
for standard processing of climate and forecast model data.

This document describes additional {\CDO} operators to compute climate indices
of daily temperature and precipitation extreme.
The definition of these climate indices are from the European Climate
Assessment (ECA) project.

The climate indices were implemented in {\CDO} by Ralf Quast
(Brockmann Consult) on behalf of the Service Gruppe Anpassung (SGA) in 2006.
SGA was part of the Model and Data Group (M\&D) at the MPI for Meteorology.
In 2010, the Model and Data Group became the Data Management
department at DKRZ (Deutsches Klimarechenzentrum) and the SGA was
disintegrated. 
For this reason there is no further user support available for these {\CDO} operators.
