Abstract
Sea Surface Temperature (SST) is a key variable in
air-sea interactions, partly controlling the oceanic
uptake of CO2 and the heat exchange between the
ocean and the atmosphere, amongst others. Satellite
SSTs are representative of skin and sub-skin temperature,
i.e. in the upper millimetres of the water
column where most of the heat is absorbed and
where the exchange of heat and momentum with
the atmosphere occurs. During day-time and under
favourable conditions of low winds and high insolation,
diurnal warming of the upper layer poses challenges
for validating and calibrating satellite sensors
and merging SST time series. When radiometer signals,
typically from satellites, are validated with in
situ measurements from drifting and moored buoys
a general mismatch is found, associated with the different
reference depth of each type of measurement.
A generally preferred approach to bridge the gap between
in situ and remotely obtained measurements,
is through modelling of the upper ocean temperature.
Models that have been used for this purpose
vary from empirical parametrisations mostly based
on the wind speed and solar insolation to ocean models
that solve the 1 dimensional equations for the
transport of heat, momentum and salt. GOTM is
a model resolving the basic hydrodynamic and thermodynamic
processes related to vertical mixing in
the water column, that includes most of the basic
methods for calculating the turbulent fluxes. Surface
heat and momentum can be either calculated
or externally prescribed while the model includes a
2-band parametrisation for the penetration of light
in the water column. From the analysis it has been
found that the data used to initialise the model, especially
the temperature profiles, along with the selected
light extinction scheme hold a key role in the
agreement of the modelled output with observations.
To improve the surface heat budget calculation and
distribution of heat in the water column, the GOTM
code was modified to include an additional method
for the estimation of the total outgoing long-wave
radiation and a 9-band parametrisation for the light
extinction, correspondingly. New parametrisations
for the stability functions, i.e. the quantities in the
turbulent diffusivity expressions associated with vertical
mixing, have been included. Preliminary results
demonstrate the successful implementation of the
new parametrisations and the ability of the model to
reproduce the diurnal signals seen from the in situ
measurements. In addition, special focus is given
to testing and validation of different model set-up
combinations using experimental data from different
campaigns in the Atlantic Ocean, in order to establish
a model set-up that can be applied to different
regions.
Original language | English |
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Title of host publication | Proceedings of the ESA SOLAS Earth Observation for Ocean-Atmosphere Interactions Science 2014 |
Number of pages | 8 |
Publisher | European Space Agency |
Publication date | 2014 |
Publication status | Published - 2014 |
Event | Earth Observation for Ocean-Atmosphere Interactions Science 2014 - Frascati, Italy Duration: 28 Oct 2014 → 31 Oct 2014 |
Conference
Conference | Earth Observation for Ocean-Atmosphere Interactions Science 2014 |
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Country/Territory | Italy |
City | Frascati |
Period | 28/10/2014 → 31/10/2014 |