Predictions in the North Sea
245
13.1.4 Chapter Contents
Section 13.2 contains a description ofthe existing forecasting systems relating to
dynamics and mixing in the seas of N. W. Europe. Details of the dynamical processes are relegated to appendices: Appendix A provides definitions of the various
modes and applications of model simulations, Appendix B contais Dynamics (tides
and surges) and Contaminant Mixing, Appendix C Residual Horizontal Circulation; Appendix D Vertical Exchange and Appendix E the Seasonal Cycle. In section 13.3 we offer the discussion of mixing of tracers inc1udes: temperature,
salinity, caesium 137, sediments, metals in both dissolved and particulate phases
and nutrients.
Section 13.3 discusses future developments.
13.2 Forecasting dynamics and contaminant mixing in the Seas
of North Western Europe
Table 13.2 is a summary ofthe characteristic features and stage of development
of forecast systems in the N.W. European ShelfSeas ranging from dynamics to the
mixing ofboth conservative and non-conservative tracers.
Indirectly, this table answers the questions (b) and (c) raised in section 13.1, i.e.
what we can and can't predict now. A system shown to be 'Operational' c1early
indicates what can be done, a system shown to be 'Experimental' is c1early under
deve1opment. (See Appendix A for an explanation of the terms: Operational, Preoperational, Climate Mean and Experimental). For some parameters, such as storm
surges and waves, their energy (or mass) dissipates rapidly. This enables simulations to be made, in the same manner, for time scales from hours to decades. Other
parameters, such as temperature or salinity, have a longer memory and simulations
are restricted by the difficulties of initialisation (or re-initialisation/chronology).
The temporal and spatial resolutions may be limited by the corresponding resolution of initial boundary and forcing conditions.
As an illustration of the above, a major constraint in forecasting mixing of contaminants is the limited knowledge of the amount, timing and location of inputs.
For non-conservative substances, these limitations in defining sources, sinks and
open boundary and exchange rates are exacerbated by the difficulties in quantifying the complex interactions between dissolved and particulate phases and between
chemical and biological parameters. Oceanic and atmospheric exchanges may
constitute a source or a sink (or both) for mass, momentum or energy. Thus as a
background to appreciating such constraints, Table 13.2 aims to indicate the
dependency of the various simulations on exchanges within the Atlantic, the atmosphere, coasts and rivers.
Since the N.W. European Shelf Seas are semi-enclosed, the longer term distributions of many tracers entering from the ocean or the coasts are governed, overwhelmingly, by the persistent pattern of residual horizontal circulation. Conversely
the distributions of tracers entering via the atmosphere or seabed may be primarily
245
13.1.4 Chapter Contents
Section 13.2 contains a description ofthe existing forecasting systems relating to
dynamics and mixing in the seas of N. W. Europe. Details of the dynamical processes are relegated to appendices: Appendix A provides definitions of the various
modes and applications of model simulations, Appendix B contais Dynamics (tides
and surges) and Contaminant Mixing, Appendix C Residual Horizontal Circulation; Appendix D Vertical Exchange and Appendix E the Seasonal Cycle. In section 13.3 we offer the discussion of mixing of tracers inc1udes: temperature,
salinity, caesium 137, sediments, metals in both dissolved and particulate phases
and nutrients.
Section 13.3 discusses future developments.
13.2 Forecasting dynamics and contaminant mixing in the Seas
of North Western Europe
Table 13.2 is a summary ofthe characteristic features and stage of development
of forecast systems in the N.W. European ShelfSeas ranging from dynamics to the
mixing ofboth conservative and non-conservative tracers.
Indirectly, this table answers the questions (b) and (c) raised in section 13.1, i.e.
what we can and can't predict now. A system shown to be 'Operational' c1early
indicates what can be done, a system shown to be 'Experimental' is c1early under
deve1opment. (See Appendix A for an explanation of the terms: Operational, Preoperational, Climate Mean and Experimental). For some parameters, such as storm
surges and waves, their energy (or mass) dissipates rapidly. This enables simulations to be made, in the same manner, for time scales from hours to decades. Other
parameters, such as temperature or salinity, have a longer memory and simulations
are restricted by the difficulties of initialisation (or re-initialisation/chronology).
The temporal and spatial resolutions may be limited by the corresponding resolution of initial boundary and forcing conditions.
As an illustration of the above, a major constraint in forecasting mixing of contaminants is the limited knowledge of the amount, timing and location of inputs.
For non-conservative substances, these limitations in defining sources, sinks and
open boundary and exchange rates are exacerbated by the difficulties in quantifying the complex interactions between dissolved and particulate phases and between
chemical and biological parameters. Oceanic and atmospheric exchanges may
constitute a source or a sink (or both) for mass, momentum or energy. Thus as a
background to appreciating such constraints, Table 13.2 aims to indicate the
dependency of the various simulations on exchanges within the Atlantic, the atmosphere, coasts and rivers.
Since the N.W. European Shelf Seas are semi-enclosed, the longer term distributions of many tracers entering from the ocean or the coasts are governed, overwhelmingly, by the persistent pattern of residual horizontal circulation. Conversely
the distributions of tracers entering via the atmosphere or seabed may be primarily