SMEAR I
SMEAR STATIONS
Värriö — Subarctic pine forest
SMEAR I is located at the top of the
hill at the Arctic-alpine timberline in
Värriö Nature park near the Russian
border.
Stations for measuring Forest - Ecosystem Atmosphere Relationships
The SMEAR-stations (Stations for measuring Forest - Ecosystem Atmosphere Relationships) measure the relationship of atmosphere and forest in the boreal climate zone and are maintained by both the Department of Forest Sciences and the Department of Physical Sciences at the
University of Helsinki.
SMEAR II
The main idea of the SMEAR Stations is continuous, comprehensive measurement of fluxes, storages and concentrations in the land ecosystem - atmosphere continuum. The major coupling mechanisms between atmosphere and land surfaces are the fluxes of energy, momentum,
water, carbon dioxide, atmospheric trace gases and atmospheric aerosols.
Understanding of couplings and feedbacks is the basis for predictions of changes in the system formed by atmosphere, vegetation and soil. A
better quantification of the agents that cause climate change as well as the emissions and removals of compounds, will provide more accurate
projections of future atmospheric composition and hence climate.
Hyytiälä — Southern boreal pine
forest
The SMEAR II station is located in Juupajoki, close to the Hyytiälä Forestry
Field Station in Southern Finland.
SMEAR I - Clean environment with
pollution episodes
SMEAR IV - Station to study the interactions
of aerosol particles and clouds
SMEAR II - Super-site, extensive long-term
measurements
Science through a super-site infrastructure
SMEAR III - Land-Atmosphere and Ecosystem
measurements in urban environment
The origins of all the SMEAR stations are closely linked to Prof. Markku Kulmala. His work on heat and mass transfer started in 1983 at the
University of Helsinki, Finland. He established his own research group, size of 5 persons, at Physics Department. The first turning point for the
work took soon place. In April 1986 the Chernobyl nuclear plant accident occurred in Ukraine, Soviet Union. Large quantities of radioactive
contamination were released into the atmosphere, making their way also to Finland. At that time the Finnish ministry of Education decided
to make a major investment on measurement equipment for atmospheric monitoring. The new equipment was placed in Hyytiälä forest field
station of the University of Helsinki, in Central Finland. The development of the “SMEAR - super site” concept measuring the “Forest Ecosystem – Atmosphere Relationships” was started. Today we have four SMEAR -stations in around Finland: SMEAR I in Värriö was established
in 1990-1991, followed by SMEAR II in Hyytiälä (1995), SMEAR III in Helsinki (2004) and SMEAR IV in Puijo (2008). Before Kulmala’s work,
there existed no real continuous observations on atmospheric aerosols and their dynamics, even though atmospheric aerosols are considered as
key factors in predicting the future climate.
Nowadays, Markku Kulmala’s research unit at the University of Helsinki, is a world leader in the areas of atmospheric aerosol formation and
biogenic background processes leading to aerosol formation. The research of the unit is focused on reducing the scientific uncertainties related to
global climate change, particularly those concerning aerosols and clouds.
The main emphasis at SMEAR I is on interactions between trees and atmosphere, air quality and aerosols. It is located at an adequate distance from the emission sources of Kola Peninsula (located less than
200 km away) in order to study the effects of pollutants on air quality and fragile subarctic ecosystem.
There are excellent possibilities to investigate the effects of acute pollution episodes on ecophysiological
processes such as photosynthesis due to clear differences in concentrations between episodes and clean
air. Another aim of the station is to study the long-term effects of air pollution and harsh growing conditions on forest growth.
The most comprehensively equipped SMEAR - station - SMEAR II - is built to study material and energy
flows in atmosphere - vegetation - soil - continuum at different temporal and spatial scales. The station
is a versatile and automatic unit operating in continuous and long-term manner, aiming to solve crossdisciplinary (physics, chemistry and biology) environmental problems.
The goal of the SMEAR -type research infrastructure is to improve understanding of how interacting
physical, chemical and biological processes transport and transform energy and matter through the
land-atmosphere interface, particularly emphasizing interactions and feedbacks at all scales: from past
to future and from local scale to global scale.
SMEAR III
The SMEAR III station started in Helsinki (Kumpula campus of the University of Helsinki) in autumn
2004. The idea was to expand the versatile atmospheric measurements to an urban area which is very different from natural environments. The Kumpula site is located about 4 km from downtown of Helsinki.
Measurements are made at 31 meters high tower which is equipped with meteorological instrumentation at several heights. The SMEAR III station has also an own weather station, located on the roof of
Physicum building, about 50 meters above ground level. The ecosystem research lies in Viikki campus,
7 km from downtown of Helsinki. The urban tree measurements cover a wide array of ecophysiological
measurements, e.g. transpiration, stem diameter and soil properties.
SMEAR IV
The Puijo station in Kuopio joined the SMEAR network in 2009. At Puijo tower the idea is to study the
interactions of aerosol particles and clouds, especially the activation of aerosol particles into cloud droplets. The measurements in Puijo cover aerosol size distribution and number concentration, light scattering from and absorption to aerosol particles, cloud droplet size distribution, trace gas concentration, and
several meteorological parameters.
Helsinki — Urban station
The station is situated in two different
locations in Helsinki, Kumpula and
Viikki.
Puijo measurement station in Kuopio
The Puijo station is situated in two
locations, Puijo and Savilahti, both
nearby the city of Kuopio.
smart-SMEAR
Smart-SMEAR is an interface to visualize the data measured in SMEAR
I - III stations.
The SMEAR ecosystem and atmosphere measurements are scientifically the most important part of Värriö, done automatically all
year round, day and night. The station also collects datasets for
long-term ecological research.
At Savilahti, an automated weather station measures several meteorological parameters, including the
cloud base height measured with a ceilometer. In addition to the weather measurements, aerosol optical
properties are measured by using a sun photometer.
The development of these comprehensive stations has provided us with huge amounts of continuous
data. In order to be able to work efficiently with these datasets, improved tools are needed. SmartSMEAR is an answer to this need.
Smart-SMEAR is a tool that can be used for a rapid visualization of daily, weekly, monthly and annual
datasets. In order to be able to refine proper research questions, an overview of data is needed. Besides,
the smart-SMEAR tool can also be used for knowledge transfer and educational purposes.
Smart-SMEAR can be found here: http://www.atm.helsinki.fi/~junninen/
During the ´90s the measuring activity at the station has increased to cover ecophysiological, meteorological, gas and particle measurements in addition to the air pollutant measurements.
Markku Kulmala, Pertti Hari and colleagues started the SMEAR II station in 1995, with
an extensive range of measurement interests. The station has several operation units: a 127
m high tower for atmospheric and flux measurements, a 18 m tower for irradiation and
flux measurements and another for tree ecophysiological measurements. Soil and soil water measurements are performed on two catchment areas, and the lake measurement unit
provides continous data on fluxes over a freshwater lake. An adjacent fen ecosystem site in
Siikaneva provides data on greenhouse gas exchange in a natural wetland. Solar irradiance is
measured from 280 to 800 nm with a radio spectrometer.
The instrumentation at the SMEAR III covers aerosol dynamics and atmospheric chemistry,
micrometeorology, weather monitoring and ecophysiology of trees growing in the urban
environment. Measurements in Kumpula site include profiles of the temperature and wind
and radiation components. The fluxes of sensible heat, momentum, carbon dioxide and water vapour are measured by eddy covariance technique. Measurements in Viikki aim to find
economical and practical means for providing adequate resources for urban trees growing
in normal street environment. Particular attention is paid to finding suitable planning and
building solutions for optimum tree growth in the local climate.
The instrumentation covers measurement of aerosol dynamics, cloud
droplet properties, optical measurements, trace gases and meteorological parameters. The characteristic
features at SMEAR IV are the elevated
location in a semi-urban area and the
site being frequently in cloud.
Measurements of the direct solar radiation provide information
to retrieve the columnar aerosol optical depth, while the sky radiance measurements can be inverted to produce aerosol optical properties such as size distribution, single scattering albedo,
phase functions, and the complex index of refraction. Furthermore, the global solar radiation is measured with a pyranometer
, spectral diffuse and direct components are measured with an
ultraviolet multi-filter rotating shadowband radiometer.
The aim is to combine as much different datasets as possible on
one screen, so that one can detect causal relationships directly
from graphs. Above all, this tool can be used for studying connections between air mass trajectories and observations on stationary
measurement site. Long-range transport of pollutants, effects of
meteorology during the air mass travel, effects of air mass origin,
reasons for new particle formation or episodes of pollutants are
examples of problems that this tool can help to solve.
SMEAR II measurements
Atmosphere
Atmospheric measurements aim to the analysis of emission, formation,
transport and deposition of gaseous as well as particulate pollutants including their role in tropospheric cloud formation. Sub-projects within
atmospheric research are aerosols, atmospheric chemistry, cloud microphysics, micrometeorology and irradiation. These measurements are facilitated by a mast and tower built up in the forest.
Cloud microphysics:
• Cloud droplet formation
• Climate change research
Micrometeorology:
• Forest-atmosphere interactions
• Carbon, water and energy balance
• Deposition of pollutants-eddy-correla tion and gradient methods
Atmospheric chemistry:
• Gaseous pollutants SO2, NOx, O3
• UV-measurements
• Photochemistry
Aerosols: • Particle size measurements
• Distribution 3-100 nm and 10-800nm
• Photochemical smog
• Aerosol formation
• Horizontal and vertical profiles
SMEAR II
Contact Information
Station for measuring Forest - Atmosphere Relations
University of Helsinki, Forestry Field Station, Hyytiälä
61°51`N, 24°17`E
ATMOSPHERE
• aerosols
• atmosphere chemistry
• cloud microphysics
• micrometeorology
• irradience
TREE
• gas exchange
• water flows
• growth and structure
• canopy light
• environment
SMEAR
Website
processing &
data storage
LAKE
http://www.atm.helsinki.fi/SMEAR/
PEATLAND
SOIL
• water and nutrients
• gas concentrations
• temperature
Soil
Soil measurements aim to the analysis of whole stand water, carbon
and nutrient budgets. For this purpose the amount of incoming, stored
and outflowing elements are continuously monitored and measured in
two adjacent watersheds. Sub-topics within soil research are: water and
element budgets, soil physical, chemical and biological processes, and
tree-soil-atmosphere interactions
Water and element budgets:
• Amount and distribution of precipitation
• Amount and tension of water in soil
• Bulk deposition
• Throughfall, litterfall
• Site outflow
• Elements measured: H+, Al3+, Ca2+, Mg2+, K+, NO3, PO3-4, SO2-4, Cl-,DOC
Soil physical processes:
• Soil temperature, freezing and thawing
• Soil heat conductivity
Tree-soil-atmosphere interactions
• Activity of soil biological processes creating material flows in and from soil
• Nutrient uptake and balance
• Aerosol formation
• Elements measured: CO2, CH4, N2O, amines, VOC
Tree
The tree measurements aim to comprehensive understanding of the effects of environment on whole tree structure and forest ecosystem functions, and ecosystem feedbacks to environment. Sub-topics within tree
research are: gas exchange, carbon and nitrogen metabolism, water and
assimilate transport, and growth of trees. These measurements are facilitated by the tower reaching the top of the canopy.
Gas exchange and metabolism:
• Photosynthesis, respiration
• Transpiration and water uptake
• Light use and energy dissipation
• SO2, O3 and NOx deposition and uptake
• VOC production and emission
• Carbohydrate, lipid and protein metabolism
Transport:
• Water and assimilate transport within tree and between tree and soil
• Hydraulic conductance of wood
Some 50 to 100 people are involved in the research carried out at the
Growth:
SMEAR II, and they produce about 120 peer-reviewed research articles
• Canopy structure and development
annually. The station has been involved in more than 15 EU projects.
• Tree diameter, height , root and needle growth
Stations for measuring Forest - Ecosystem Atmosphere Relationships
http://www.helsinki.fi/hyytiala/english/index.htm
Project Leaders
Adjunct professor Jaana Bäck
Academy Professor Markku Kulmala
Professor Timo Vesala
Dept. of Forest Sciences
Dept. of Physics
Dept. of Physics
P.O.Box 27
P.O.Box 64
P.O.Box 64
FIN-00014
FIN-00014
FIN-00014
University of Helsinki
University of Helsinki
University of Helsinki
FINLAND
FINLAND
FINLAND
Tel: +358-45-6337941
Tel: + 358-9-191 50756
Tel: + 358-9-191 50862
Fax:+358-9-19158100
Fax:+ 358-9-191 50717
Fax:+ 358-9-191 50717
E-mail: Jaana.Back@helsinki.fi
E-mail: markku.kulmala@helsinki.fi
E-mail: timo.vesala@helsinki.fi
Partners
University of Helsinki and University of Eastern Finland
•
Departments of Forest Sciences and Physics
•
Finnish Meteorological Institute