.. _energy_offshore:

Energy Offshore
===============

Overview 
--------
Energy Offshore provides information about weather window statistics, i.e., suitable conditions for maritime operations in the North Sea - Baltic Sea domain.


Application output
------------------
The application output provides a long-term average view of expected weather windows to support offshore operations. Exceedance statistics of surface wind speed and sea ice cover are
computed as follows:

* Wind speed exceedance statistics:

  * Number of days in a month with wind speed exceeding 10, 18, and 21 m/s wind speeds at the surface (10 m). Note that hourly output is used, so any day with an hourly average wind speed exceeding one of the above limits is considered as exceeding.

* Sea ice thickness exceedance statistics:

  * Number of days in a month exceeding 5 cm, 40 cm, 60 cm sea ice thickness.

* Sea ice concentration exceedance statistics:

  * Number of days in a month exceeding 15% sea ice concentration.

* Weather window statistics:

  * Frequency of 3-, 5-, and 7-day weather windows (i.e. consecutive days during which a given limit is not exceeded) for the above exceedance statistics.

Accessing the data
------------------

.. note::

   Data for this application will become available on the
   DestinE Data Lake in a forthcoming update.

Scientific Evaluation
---------------------

.. note::

   Scientific evaluation for this application will be available
   in a forthcoming update.

.. Data quality and known biases
.. -----------------------------
.. Energy offshore output depends directly on the performance of the underlying models. The wind speed statistics have shown good performance over the ocean regions in respect to both ERA5 and CERRA reanalysis data - with Climate DT simulations providing generally better performance than ERA5 in coastal regions due to higher resolution. Due to the lack of a reliable reference dataset the sea ice thickness bias is unclear in the region, sea ice area is generally overestimated in the Baltic Sea. Sea ice concentration in the Baltic Sea is known to be overestimated in IFS-NEMO and IFS-FESOM, for ICON the sea ice concentration compares well with other products in the Baltic Sea.