prevailing surface currents from 7–10 cm/s at the outer boundaries and up to
1–2 cm/s at the center of the LB; the current velocities decrease significantly with
depth. At the same time, observations confirm the existence of a mesoscale lens at
medium depths of 250–700 m over the deepest part of the LB. The evolution of the
intratermocline lens, originally located in the central part of the LB depending on
different types of velocity fields and the topographic effect are investigated using
the contour dynamics method within the frames of the three-layer model.
Observation Materials and Methods
Temperature and salinity data measured by the Argo floats covering the 10-year
period from 2005 to 2014 [3] were used to study the hydrological structure and
water dynamics in the LB. The studied area includes the North Atlantic (NA) and
the Polar Seas (PS) of the Arctic Ocean (AO) from 55° to 80° N and from 30° W to
15° E. In this area about 17,600 temperature and salinity profiles from 125 Argo
floats have been collected during 10 years of observations. In the LB area (68°–73°
N and 5° W–12° E) there are 3273 profiles measured by 73 Argo floats. Seasonal
mean data in addition to the 10-year annual mean fields were calculated in this
region using 835 Argo profiles in winter, 679 in spring, 891 in summer, and 868 in
autumn.
We used the AMIGO method ([10], see also http://argo.ocean.ru) for the data
processing. Spatial resolution of data in the calculated database is one degree by
longitude and latitude, the time resolution is one month. During the processing of
the Argo profiles, we used the method of the variational interpolation of measurements onto a regular grid, followed by a model hydrodynamic adjustment of the
fields. Such a procedure minimizes the errors when transferring irregularly located
measurements into the regular grid; hence, the solution passes as close to the data as
possible. At the final stage, using the ocean general circulation model in the
diagnostic and hydrodynamic adjustment mode, we calculated the balanced
monthly means and climatological temperature, salinity, density, and velocity fields
based on the Argo data [10].
Taking into account that the one-degree calculation grid is rough for detecting
and tracking the motion of mesoscale vortices with an average radius of about
37 km [15], we made an attempt to describe the structure and dynamics of the PS
waters on the basis of the materials described above. The annual mean temperature,
salinity, density, and flow velocity fields in this region were constructed at the
depths from the sea-surface (associated with the 30 m level) to 1500 m depth. The
maps and vertical sections of these characteristics in the central part of the LB,
limited on the map by the isobath 3200 m, have clearly shown the existence of the
AV at depths of 200–800 m. The vortex center is located at the point with coordinates 69.5° N, 3.5° E, which agrees with the results by Alekseev et al. [1], Ivanov
and Korablev [6, 7], Köhl et al. [8], and Raj et al. [15].
Evolution of an Intrathermocline Lens …
335
1–2 cm/s at the center of the LB; the current velocities decrease significantly with
depth. At the same time, observations confirm the existence of a mesoscale lens at
medium depths of 250–700 m over the deepest part of the LB. The evolution of the
intratermocline lens, originally located in the central part of the LB depending on
different types of velocity fields and the topographic effect are investigated using
the contour dynamics method within the frames of the three-layer model.
Observation Materials and Methods
Temperature and salinity data measured by the Argo floats covering the 10-year
period from 2005 to 2014 [3] were used to study the hydrological structure and
water dynamics in the LB. The studied area includes the North Atlantic (NA) and
the Polar Seas (PS) of the Arctic Ocean (AO) from 55° to 80° N and from 30° W to
15° E. In this area about 17,600 temperature and salinity profiles from 125 Argo
floats have been collected during 10 years of observations. In the LB area (68°–73°
N and 5° W–12° E) there are 3273 profiles measured by 73 Argo floats. Seasonal
mean data in addition to the 10-year annual mean fields were calculated in this
region using 835 Argo profiles in winter, 679 in spring, 891 in summer, and 868 in
autumn.
We used the AMIGO method ([10], see also http://argo.ocean.ru) for the data
processing. Spatial resolution of data in the calculated database is one degree by
longitude and latitude, the time resolution is one month. During the processing of
the Argo profiles, we used the method of the variational interpolation of measurements onto a regular grid, followed by a model hydrodynamic adjustment of the
fields. Such a procedure minimizes the errors when transferring irregularly located
measurements into the regular grid; hence, the solution passes as close to the data as
possible. At the final stage, using the ocean general circulation model in the
diagnostic and hydrodynamic adjustment mode, we calculated the balanced
monthly means and climatological temperature, salinity, density, and velocity fields
based on the Argo data [10].
Taking into account that the one-degree calculation grid is rough for detecting
and tracking the motion of mesoscale vortices with an average radius of about
37 km [15], we made an attempt to describe the structure and dynamics of the PS
waters on the basis of the materials described above. The annual mean temperature,
salinity, density, and flow velocity fields in this region were constructed at the
depths from the sea-surface (associated with the 30 m level) to 1500 m depth. The
maps and vertical sections of these characteristics in the central part of the LB,
limited on the map by the isobath 3200 m, have clearly shown the existence of the
AV at depths of 200–800 m. The vortex center is located at the point with coordinates 69.5° N, 3.5° E, which agrees with the results by Alekseev et al. [1], Ivanov
and Korablev [6, 7], Köhl et al. [8], and Raj et al. [15].
Evolution of an Intrathermocline Lens …
335