Glossary
Analysis
A procedure to project the state of the atmosphere or any system as known from a finite set of imperfect, irregularly distributed observations onto a regular grid (AMS, 2000). The analysis is usually produced with the aid of numerical models and data assimilation systems. See also re-analysis.
Consistent data set
Data sets are referred to as consistent in case they the parameters of the data sets do not show any apparent conflicts, that is the parameters are physically plausible. For example, if a wave model hindcast has been performed with winds from data set A the wave model hindcast is referred to as being consistent with data set A. It is not necessarily consistent with winds from a different data set.
Data assimilation
The combination of diverse data, possibly sampled at different times and intervals and different locations, into a unified and consistent description of a physical system (AMS, 2000).
Hindcast
A retrospective analysis or re-analysis of the state of a dynamical system with the aid of a numerical model. In contrast to forecasts where observations are available only for the initialization of the forecast, they are generally known for the entire hindcast period and may assimilated any time in the course of the production of the hindcast. Hindcast are sometimes also referred to as reconstructions.
Homogeneous data
A data set is referred to as homogeneous in case it is free of contaminations such as changes in instrumentation, measurement techniques or observational practices. The latter are usually referred to as inhomogeneity or a lack of homogeneity. In particular when long-term changes are studied inhomogeneities may obscure the real (physical) signals and may lead to misinterpretations.
HIPOCAS
A project funded by the European Union to provide high-resolution and consistent meteorological-oceanographic hindcasts for the coastal areas of Europe.
Inhomogeneity
See homogeneous data.
netCDF
Network Common Data Form (netCDF) is an interface provided by Unidata for array-oriented data access and a library that provides an implementation of the interface. The netCDF library also defines a machine-independent format for representing scientific data. Together, the interface, library, and format support the creation, access, and sharing of scientific data. For details see the Unidata homepage .
Numerical model
A computer program for simulating, predicting or hindcasting the behavior of a dynamical system such as the atmosphere or the ocean.
Projection
See scenario.
Re-analysis
An analysis that is performed with a frozen numerical model and data assimilation system. Re-analyses are performed to reduce inhomogeneities in the data sets in particular those caused by changes in the methods the analyses have been performed.
Reconstruction
A retrospective analysis or re-analysis of the state of a dynamical system with the aid of a numerical model. In contrast to forecasts where observations are available only for the initialization of the forecast, they are generally known for the entire period and may assimilated any time in the course of the production of the reconstruction. Reconstructions are named hindcasts as well.
Scenario
A technique to answer question of the type “What happens if ….?” Usually some assumptions such as about e.g. the development of future greenhouse gas concentrations are made and the subsequently the consequences of these developments are studied with the aid of numerical models. The latter process is frequently called projections. Scenarios are thus tools to study the sensitivity of a system to a range of prescribed future developments.
Storm surge
Usually a rise and onshore surge of sea water as the result of primarily the winds of a storm and secondarily of the surface pressure drop near the storm center (AMS, 2000).
WASA
A project funded by the European Union that changing storminess and waves in the Northeast Atlantic and the North Sea mainly with the aid of numerical models, hindcasts and scenarios.
netCDF
Network Common Data Form (netCDF) is an interface provided by Unidata for array-oriented data access and a library that provides an implementation of the interface. The netCDF library also defines a machine-independent format for representing scientific data. Together, the interface, library, and format support the creation, access, and sharing of scientific data. For details see the Unidata homepage .
netcdf
Numerical model
A computer program for simulating, predicting or hindcasting the behavior of a dynamical system such as the atmosphere or the ocean.
Projection
See scenario.
Re-analysis
An analysis that is performed with a frozen numerical model and data assimilation system. Re-analyses are performed to reduce inhomogeneities in the data sets in particular those caused by changes in the methods the analyses have been performed.
Reconstruction
A retrospective analysis or re-analysis of the state of a dynamical system with the aid of a numerical model. In contrast to forecasts where observations are available only for the initialization of the forecast, they are generally known for the entire period and may assimilated any time in the course of the production of the reconstruction. Reconstructions are named hindcasts as well.
Scenario
A technique to answer question of the type “What happens if ….?” Usually some assumptions such as about e.g. the development of future greenhouse gas concentrations are made and the subsequently the consequences of these developments are studied with the aid of numerical models. The latter process is frequently called projections. Scenarios are thus tools to study the sensitivity of a system to a range of prescribed future developments.
Storm surge
Usually a rise and onshore surge of sea water as the result of primarily the winds of a storm and secondarily of the surface pressure drop near the storm center (AMS, 2000).
WASA
A project funded by the European Union that changing storminess and waves in the Northeast Atlantic and the North Sea mainly with the aid of numerical models, hindcasts and scenarios.
Reference
AMS, 2000: Glossary of Meteorology, Published by the American Meteorological Society, Boston, USA. Glossary of Meteorology