- Middle Atmosphere and Ozone
- Surface UV From Ground-Based and Satellite Instruments
- Effects of Solar Proton and Electron Precipitation in the Polar Regions
- Stellar Scintillations for Mapping Turbulence and Gravity Waves
Middle Atmosphere and Ozone
Ozone in the middle atmosphere is crucial for protecting biosphere from harmful UV-radiation. The dramatic loss of ozone in Antarctic (ozone hole), the similar but weaker loss of ozone in Arctic, and the general slow decline of ozone in the stratosphere have been the object of intensive experimental and modeling studies since 1985 when the ozone hole was first detected. The main processes behind ozone loss are already quite completely understood. There are some signs that the recovery of ozone has now started but the complete recovery is expected to take about fifty years. Ozone research in the Atmospheric Remote Sensing group is largely based on the use of data from three satellite instruments: GOMOS on Envisat, Osiris on Odin and OMI on EOS-Aura. Time series and climatologies of ozone and related nitrogen compounds (NO2 and NO3) have been calculated and compared to the ones from models. An important research direction is the interaction of the middle atmosphere ozone and NO2 with energetic particle precipitation from the Sun (for more information click here).
Surface UV From Ground-Based and Satellite Instruments
The amount of solar UV radiation reaching the Earth's surface is mainly affected by the solar elevation and the atmospheric ozone absorption. Moreover, the surface albedo and the clouds and aerosols effect modulate the surface UV radiation levels. Changes in UV radiation at the surface may strongly affect human health and terrestrial and aquatic ecosystems. The UV Index, defined as the EDR (mW/m2) divided by 25, provides useful information for the public in order to prevent overexposure to the Sun's rays. Surface UV radiation estimates have been provided from satellite-based instruments such as OMI (Ozone Monitoring Instrument) and GOME-2 (Global Ozone Monitoring Experiment-2).The amount of surface UV radiation increased during the last 30 years because of the effect of the ozone decrease, combined with the effect of the cloud-aerosol reflectivity changes. These long-term changes can in general affect the global bio-geochemistry (carbon cycle), climate and their interactions. For more information see OMI UV web pages.
Effects of Solar Proton and Electron Precipitation in the Polar Regions
Energetic particle precipitation affects the neutral chemistry of the Earth's atmosphere in the polar regions. Energetic particles in this means either solar protons, cosmic rays or auroral electrons that are transported in the Earth's atmosphere by strong solar wind and/or big eruptions on the Sun's surface. As propagating in the Earth's atmosphere the energetic particles ionise atmospheric neutral molecules. As a result several ozone depleting substances, such as odd hydrogen and odd nitrogen, are being formed. Ozone is destroyed in catalytic chemical cycles in the middle and upper atmospheres with also long-term effects. Because ozone plays an important role in the heat balance of the atmosphere through UV absorption, changes in ozone balance affect also the dynamics of the atmosphere, possibly also the climate on Earth's surface. For more information, see the CHAMOS web pages.
Stellar Scintillations for Mapping Turbulence and Gravity Waves
The upward propagating waves and their breaking into turbulence are of fundamental importance for the dynamics and mixing within the middle atmosphere.
The use of satellite observations of stellar scintillation for studying small-scale irregularities of the Earth atmosphere is a relatively new approach that allows quantification of the activity of small-vertical-scale gravity waves (GW) and their breaking into turbulence. After the launch of the GOMOS (Global Ozone Monitoring by Occultation of Stars) instrument on board the Envisat satellite in March 2002, scintillation measurements became available with global coverage. The method for reconstruction of GW and turbulence spectra parameters from stellar scintillations has been recently developed and adapted to GOMOS measurements. GOMOS data have allowed obtaining information about spatiotemporal distributions of gravity wave and turbulence spectra parameters at altitudes 25-50 km. For more information click here.
AC SAF (Satellite Application Facilities for Atmospheric Composition Monitoring)
Utilising specialist expertise from the Member States, Satellite Application Facilities (SAFs) are dedicated centres of excellence for processing satellite data and form an integral part of the distributed EUMETSAT Application Ground Segment. AC SAF consortium members develop radiative transfer calculation methods and other algorithms for creating atmospheric remote sensing data from GOME-2 and IASI instruments onboard of the polar-orbiting satellites Metop-A and B. We also validate the data products and provide associated dissemination and user services. AC SAF produces NRT, offline and data record products including trace gases, surface radiation products and aerosols. FMI is the leading institute for the project and hosts one of the data archives as well as develop the offline UV products. For more information, see AC SAF web pages.
SAMPO Direct Readout (DR) service
The SAMPO service offer Direct Readout (DR) satellite measurements over the Northern Hemisphere and it continues the bath of the OMI VFD service. The measurements are from OMI (Ozone Monitoring Instrument) onboard the EOS-Aura satellite and OMPS instrument onboard the Suomi-NPP satellite. The images and data come available within 20 minutes after the satellite overpass of Sodankylä Ground Station in Northern Finland. Furthermore, the OMPS data received in Alaska is available via the service. The data is received via Direct Broadcast transmission from the satellite at the same time when it is measured. Thus, the service is faster than normal NRT delivery. The service provides latest observations of O₃, SO₂, clouds, UV index, UV daily dose and aerosols as individual and composite images as well as HDF5 data files. The applications are such as monitoring of hazardous volcanic emissions of SO₂ and aerosols, monitoring of emissions from forest fires and industrial plants, monitoring of air quality and monitoring of UV index, ozone column. The service may be used in timing of research flights and release of sounding balloons. For more information, see SAMPO web pages.