Unlike observations taken solely to support the preparations of forecasts and warnings, the availability of a continuous, uninterrupted climate record is the basis for many important studies involving a diverse array of climatological communities of which the need for homogeneous climate datasets is of utmost importance.
Changes can result in a temporal break in the record or a discontinuity caused by the monitoring program change rather than any change in the climate. From a user’s perspective, the break or discontinuity can mask the true climate and/or trends or other changes in the climate.
Therefore managing change within a climate observation program strives to maintain the intercomparability of the climate record throughout the change process. It is critical to meeting the needs of climate research, applications, and services users, as well as those of the policy community.
From the perspective of maintaining the integrity of the climate record through change, the best practice is to run the previous and the new systems/sensors in parallel. A parallel observation program allows for the identification of the necessary transfer functions, thus minimizing/eliminating the impact of the change on the climate record.
The WMO Guidelines for managing changes in climate observation programmes aim at providing managers and operators of climate monitoring networks with a set of recommended procedures/practices by which change can be managed in the observational programs in a manner that best maintains the required integrity of the climate record.