Absorbing Aerosols and Fate of the Indian Glaciers
A significant amount of fresh water is stored in the Himalayan glaciers. People in India are more and more dependent on this source of water due to population growth, urbanization, and rapid industrial development. Himalayan glaciers have been in a general state of recession since the 1850s, creating a potential threat for human livelihood in India in the future. However, it appears that while some of the glaciers are receding, others are not. The reason for this discrepancy is currently unknown.
Aerosols in Southern Asia are highly absorbing due to their large black carbon (BC) content and the occasional presence of large amounts of desert dust. This causes a reduction of solar radiation at the surface accompanied by a substantial atmospheric heating. The current and future trends of aerosol concentrations in this region are very unclear: while measurements conducted in megacities show of a decrease in aerosol concentrations over the few recent years, regional-scale measurements seem to be indicative of an increasing trend. Future aerosol concentrations in the southern Asia, in turn, depend crucially on emission control strategies in household, industrial and transport sectors.
The primary goal of this project is to quantify how the amount and properties of absorbing aerosols are affecting the glaciers mass balance in the Himalayas. We first aim to understand this relationship on a single small glacier on a mechanistic level, and then upscale this knowledge for different glaciers in the Himalayas. A study combining both atmospheric and glaciological research in the Himalayan region is very unique. Previous glaciological studies have focused on observing the glacier changes through direct or satellite observations. Atmospheric studies include remote sensing from satellites, and simulations of heating rates.
Several short term expeditions (first expedition in May 2014) will be made to the Pindari Glacier, central Himalaya during the study. On the glacier, different aerosol and glacier characteristics will be studied. Ice core drill will be used to gather information from the deeper parts (2-10m) of the active surface layer. A weather station will be installed during the first expedition. Also snow stations will be installed that will record the temperature changes in the snowpack and the snow accumulation events. The data from snow stations will be retrieved during the annual expeditions.
Today’s world is more dependent on the Arctic region than ever – a dependency that will only grow in the future. North represents invaluable natural resources, globally vital ecosystems, highly variable, aesthetic and largely undisturbed landscapes, as well as an important research platform to understand and predict the future of our dynamic planet. Evidence suggests that global warming is already changing important physical and biological systems of the Arctic. The impacts of these changes on the Arctic’s communities and livelihoods are large and projected to grow in the future. There is even a risk that rapid change in climate will cause a destabilization of ecosystems.
Our research team has focused on the impacts of climate change on snow properties and snow cover. Snow cover is a natural part of Arctic landscape for most of the year. It is an important fresh water storage, it forms an insulating cover on land and frozen inland waters, it has high reflectance of sunlight, and it is an essential element in Arctic ecosystems. For human activities snow arises technical problems but as well snow is part of good life quality and a major resource for tourism.
We aim to (1) classify of snow zones and their evolution in Lapland on the basis of snow structure and properties; (2) construct rheological models of snow cover, and (3) evaluate the sensitivity of the snow zones to climate change.
Evolution of snow cover and dynamics of atmospheric deposits in
the snow in the Antarctica
Antarctica is a major component in the climate system of the earth, acting as a large heat sink in the energy balance. The climatic conditions of Antarctica maintain the snow and ice cover that blankets almost completely the surface area of the continent. Physical properties of snow readily respond to changing environmental conditions and remote sensing signals are sensitive to these properties. The annual changes in the physical properties of the snow cover, especially in the coastal area, must be taken into account when snow cover and climate models are produced.
The general strategy was to get detailed knowledge of the physical properties of the surface layer and of the factors responsible for producing them in the research area covering a 300 km deep sector in the Dronning Maud Land. The specic objectives of the present ice sheet surface layer were to:
- Examine the spatial variation of the physical properties of snow and to acquire additional snow pit data;
- Examine the chemistry of impurities in snow;
- Determine the annual snow accumulation and ablation rates and their spatial variations;
- Extract information on the physical properties of snow and ice from satellite images; and
- Examine the life history of supraglacial and epiglacial lakes.
Fieldwork was done during FINNARP 2009 and 2010 expeditions. The sites were at the Finnish research station Aboa, a snow line from Rampen at the edge of the ice shelf pass Aboa to the station Svea, and blue ice at Basen and neighboring nunataks. Snow measurements were made using classical snow pit method, ice and snow sampling, and with automatic observation stations (surface radiation balance, penetration of sunlight into snow and ice, and temperature within the surface layer of snow and ice). Life history, physics, and ecological state of lakes were mapped.
Understanding the current and future stability and variation of Austfonna Ice Cap, Svalbard
Austfonna Ice Cap is the 7th largest ice cap in the world and constitutes the largest individual ice body on the Svalbard archipelago in Norway. Remote sensing measurements show that for the period 2002–2008 the whole area was losing mass with most of the thinning happened at the margins due to a rapid retreat of the calving fronts. The outlet glacier of Basin 3, which is one of the fastest outlet glaciers in Svalbard has experienced both dramatic summer and winter speed up since 1995. The successive acceleration results in a surge by autumn 2012 since its last active phase in ~1873, which discharges 4.2 ± 1.6 Gt/yr of ice to Barents Sea over the period 04.2012 to 05.2013.
The first stage of the project was funded by Norden SVALI (Stability and Variations of Arctic Land Ice ) and carried out at Arctic Center, Rovaniemi (01.2013 -06.2014 ). We have used the state-of-the-art full Stokes ice dynamics model, Elmer/Ice, and a higher order ice dynamics model, BISICLES, to investigate the sensitivity of the icecap's transient behavior to model physics and basal boundary conditions. A one-way coupling between ice dynamics models and a Regional Climate Model, HIRHAM, has achieved by forcing forward simulations with elevation corrected 1990-2011 Surface Mass Balance (SMB) monthly time series.
The on-going studies involve the coupling with a hydrology model and a Discrete Particle Model (DPM) aiming to understand the internally triggered mechanism at the ice/bed interface of the recent speed up of the glacier in Basin 3. This part of the projection is also partly funded by ESF MicroDICE.
Winter season in the coastal zone of Baltic Sea
In the seasonal sea ice zone (SSIZ), the wintertime is of major importance in the physics and the ecology of the basins. In general, sea ice has a remarkable influence on the physics of the freezing seas by (a) forming an insulating surface film, (b) providing high albedo, (c) modifying the salt budget of the upper layer, and (d) preventing the transfer of the wind momentum to the water body. The sea freezes, and the evolution of the sea ice and the water body progress in an interactive manner. Freezing starts from the shallow coastal areas and develops further out during the winter, while melting starts from both the land and the open ocean boundary. The last pieces of ice to disappear are remnants of large pressure ridges. When the basin of interest is located at the climatological edge of the SSIZ, there is also high inter-annual variability in the ice conditions.
The purpose of this work is to evaluate the influence of the coastal sea ice in physical and ecological properties of the water body. The study is mainly based on observations from particular coastal areas of the Gulf of Finland and the Western Gotland Basin. Heat exchange between the ocean and the atmosphere, profiles of hydrography and currents, pH and dissolved oxygen levels were analyzed both in ice-covered and open water seasons. In addition, we examine the long-term trends and the seasonal variability of the hydrography, heat content, freshwater budget and sea ice.
Lake ice in Arctic Lakes
Research in physical processes in ice-covered lakes has been growing recently due to interest in the response of mid- and high-latitude lakes to global warming. Using field measurements from several Finnish lakes, Lake Kilpisjärvi (tundra), Lake Pääjärvi (boreal), Lake Valkeakotinen (boreal) and Lake Vanajavesi (boreal), we study the properties of freshwater ice and its interaction with the underlying lake water. The first step is to analyse the collected data, and the second to develop an existing lake ice model and couple it with a mixed layer water body model. The modeling work is done in close collaboration with the GLEON (Global Lake Ecological Observatory Network, see http://www.gleon.org/) ice project which will provide a data set for about 20 lakes in Europe and North America.
The project is part of CRAICC (Cryosphere-Atmosphere Interactions under Changing Climate) and under the work package Cryospheric changes. More about CRAICC: https://www.atm.helsinki.fi/craicc/
The first outcome of the project is a Master’s thesis focusing on melt season at Lake Kilpisjärvi. The fieldwork was performed in spring 2013, when the unusually warm weather resulted in an extremely fast melting of the ice. The ice break-up took place during the field campaign, and we were able to collect data from the time periods just before, during and after the ice break-up. A similar field campaign was carried out in spring 2014, and we are now working on publishing the results from both campaigns.
A blog from the field campaign in 2013 is available in: http://arcticresearch.wordpress.com/category/blogs-from-the-field/exploring-under-ice-in-a-polar-lake-the-kilpisjarvi-edition/
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