New Data on Sea-Ice Albedo in the Laptev and Barents Seas
B.V. Ivanov
State Research Center - Arctic and Antarctic Research Institute, 38 Bering St., 199226 Sf. Petersburg, Russia
Received 3 March 1997 and accepted in revised form 9 February 1998
Abstract - Results of recent sea-ice albedo measurements carried out during the summer of
1993 in the Laptev and Barents Seas are reported. Ground-truth data were obtained with
hand-held pyranometers during a ship expedition. A relationship between the albedo of melt
puddles and their depths was revealed. The temporal variation of albedo for the main surface
types of sea ice (snow, puddles, bare and dirty ice) and a relationship between the albedo and
thickness of young ice were determined.
Introduction
The sea ice cover is an important component in the climate system. The distribution of drifting
ice and the state of its surface during summer and autumn have a pronounced influence on the
energy exchange processes in the surface layer of the atmosphere. The most important sea ice
variables, relevant for energy exchange and melting are as follows: concentration, thickness,
surface temperature and albedo. Albedo is one of the main characteristics (Chernigovskiy,
1963; Buzuev et. a!., 1965; Grenfell and Maykut, 1977). Within summer period the parameters
of ice surface and air temperature are very close, and compact cloudiness (10/10 Stcu or St)
limits the minimum values of the long-wave radiation balance during late summer to not more
than 10-20 W/m 2 . So, daily means of the turbulent fluxes and the long-wave radiation balance
are approximately equal zero. Therefore, the total heat balance of the ice surface as well as
melting processes is determined by incoming short-wave solar radiation and reflected radiation,
i.e. albedo.
At present, the several simple summer albedo parametrizations are used in thermodynamic ice
models (Semtner, 1976; Ivanov and Makshtas, 1990; Curry and Ebert, 1993). These
parametrizations are based on the relationship between albedo and ice/snow thickness or relative
area of puddles. But this information is not enough. Our ground true observations revealed a
large variation of ice surface types (for example, wet snow, dirty and bare ice, puddles, etc.)
during late summer. The determination of integral albedo, taking into consideration the
contribution of all types of ice surface, allows to improve estimations of energy exchange, ice
thickness variability and concentration.
Methods and observations
The weather and ice conditions were rather constant during our field activities in the Barents
Sea to the north-west from Franz losef Land as it is presented in Table I.
It was a typical situation for late summer in this region. On average, the ice surface
temperature was near or slightly below zero. Melting dominated on the ice cover. Turbulent
(sensible and latent) heat fluxes lay from -5 W/m 2 to + 10 W/m 2 . After a detailed analysis of the
ice surface one can distinguish four main types of ice surface as follows: puddles, wet snow,
bare ice, dirty ice. Mean values of albedo are presented in Table 2.
Basing on the results, presented in Table 2, we can obtain a new simple parametrization for
the integral albedo over a larger ice covered area. This parametrization can be used for all arctic
In: Kassens. H .. H.A. Bauch, I. Dmitrenko, H. Eicken, H.-W. Hubberten, M. Melles, 1. Thiede and L. Timokhov (eds.)
Land-Ocean Systems in the Siberian Arctic: Dynamics and History. Springer-Verlag, Berlin, 1999,59-63.
B.V. Ivanov
State Research Center - Arctic and Antarctic Research Institute, 38 Bering St., 199226 Sf. Petersburg, Russia
Received 3 March 1997 and accepted in revised form 9 February 1998
Abstract - Results of recent sea-ice albedo measurements carried out during the summer of
1993 in the Laptev and Barents Seas are reported. Ground-truth data were obtained with
hand-held pyranometers during a ship expedition. A relationship between the albedo of melt
puddles and their depths was revealed. The temporal variation of albedo for the main surface
types of sea ice (snow, puddles, bare and dirty ice) and a relationship between the albedo and
thickness of young ice were determined.
Introduction
The sea ice cover is an important component in the climate system. The distribution of drifting
ice and the state of its surface during summer and autumn have a pronounced influence on the
energy exchange processes in the surface layer of the atmosphere. The most important sea ice
variables, relevant for energy exchange and melting are as follows: concentration, thickness,
surface temperature and albedo. Albedo is one of the main characteristics (Chernigovskiy,
1963; Buzuev et. a!., 1965; Grenfell and Maykut, 1977). Within summer period the parameters
of ice surface and air temperature are very close, and compact cloudiness (10/10 Stcu or St)
limits the minimum values of the long-wave radiation balance during late summer to not more
than 10-20 W/m 2 . So, daily means of the turbulent fluxes and the long-wave radiation balance
are approximately equal zero. Therefore, the total heat balance of the ice surface as well as
melting processes is determined by incoming short-wave solar radiation and reflected radiation,
i.e. albedo.
At present, the several simple summer albedo parametrizations are used in thermodynamic ice
models (Semtner, 1976; Ivanov and Makshtas, 1990; Curry and Ebert, 1993). These
parametrizations are based on the relationship between albedo and ice/snow thickness or relative
area of puddles. But this information is not enough. Our ground true observations revealed a
large variation of ice surface types (for example, wet snow, dirty and bare ice, puddles, etc.)
during late summer. The determination of integral albedo, taking into consideration the
contribution of all types of ice surface, allows to improve estimations of energy exchange, ice
thickness variability and concentration.
Methods and observations
The weather and ice conditions were rather constant during our field activities in the Barents
Sea to the north-west from Franz losef Land as it is presented in Table I.
It was a typical situation for late summer in this region. On average, the ice surface
temperature was near or slightly below zero. Melting dominated on the ice cover. Turbulent
(sensible and latent) heat fluxes lay from -5 W/m 2 to + 10 W/m 2 . After a detailed analysis of the
ice surface one can distinguish four main types of ice surface as follows: puddles, wet snow,
bare ice, dirty ice. Mean values of albedo are presented in Table 2.
Basing on the results, presented in Table 2, we can obtain a new simple parametrization for
the integral albedo over a larger ice covered area. This parametrization can be used for all arctic
In: Kassens. H .. H.A. Bauch, I. Dmitrenko, H. Eicken, H.-W. Hubberten, M. Melles, 1. Thiede and L. Timokhov (eds.)
Land-Ocean Systems in the Siberian Arctic: Dynamics and History. Springer-Verlag, Berlin, 1999,59-63.