20 research outputs found
A chemistry-transport model simulation of middle atmospheric ozone from 1980 to 2019 using coupled chemistry GCM winds and temperatures
International audienceA Global 40-year simulation from 1980 to 2019 was performed with the FinROSE chemistry-transport model based on the use of coupled chemistry GCM-data. The main focus of our analysis is on climatological-scale processes in high latitudes. The resulting trend estimates for the past period (1980?1999) agree well with observation-based trend estimates. The results for the future period (2000?2019) suggest that the extent of seasonal ozone depletion over both northern and southern high-latitudes has likely reached its maximum. Furthermore, while climate change is expected to cool the stratosphere, this cooling is unlikely to accelerate significantly high latitude ozone depletion. However, the recovery of seasonal high latitude ozone losses will not take place during the next 15 years
Quality assurance of the Brewer UV measurements in Finland
International audienceThe quality assurance of the two Brewer spectrophotometers of the Finnish Meteorological Institute is discussed in this paper. The complete data processing chain from raw signal to high quality spectra is presented. The quality assurance includes daily maintenance, laboratory characterizations, calculation of long term spectral responsivity, data processing and quality assessment. The cosine correction of the measurements is based on a new method, and included in the data processing software. The results showed that the actual cosine correction factor of the Finnish Brewers can vary between 1.08?1.13 and 1.08?1.12, respectively, depending on the sky radiance distribution and wavelength. The temperature characterization showed a linear temperature dependence between the internal temperature and the photon counts per cycle, and a temperature correction was used for correcting the measurements. The long term spectral responsivity was calculated using time series of several lamps using two slightly different methods. The long term spectral responsivity was scaled to the irradiance scale of the Helsinki University of Technology (HUT) for the whole measurement time periods 1990?2006 and 1995?2006 for Sodankylä and Jokioinen, respectively. Both Brewers have participated in many international spectroradiometer comparisons, and have shown good stability. The differences between the Brewers and the portable reference spectroradiometer QASUME have been within 5% during 2002?2007
Quality assurance of the Brewer spectral UV measurements in Finland
The quality assurance of the two Brewer spectrophotometers of the Finnish Meteorological Institute is discussed in this paper. The complete data processing chain from raw signal to high quality spectra is presented. The quality assurance includes daily maintenance, laboratory characterizations, calculation of long-term spectral responsivity, data processing and quality assessment. The cosine correction of the measurements is based on a new method, and is included in the data processing software. The results showed that the actual cosine correction factor of the two Finnish Brewers can vary between 1.08–1.13 and 1.08–1.12, respectively, depending on the sky radiance distribution and wavelength. The temperature characterization showed a linear temperature dependence between the instruments' internal temperature and the photon counts per cycle, and a temperature correction was used for correcting the measurements. The long-term spectral responsivity was calculated using the time series of several lamps using two slightly different methods. The long-term spectral responsivity was scaled to the irradiance scale of the Helsinki University of Technology (HUT) for the whole of the measurement time-periods 1990–2006 and 1995–2006 for Sodankylä and Jokioinen, respectively. Both Brewers have participated in many international spectroradiometer comparisons, and have shown good stability. The differences between the Brewers and the portable reference spectroradiometer QASUME have been within 5% during 2002–2007
UV index climatology over the United States and Canada from ground-based and satellite estimates
Impacts of climate change on temperature, precipitation and hydrology in Finland – studies using bias corrected Regional Climate Model data
Assessment of climate
change impacts on climate and hydrology on catchment scale requires reliable
information about the average values and climate fluctuations of the past,
present and future. Regional climate models (RCMs) used in impact studies
often produce biased time series of meteorological variables. In this study
bias correction (BC) of RCM temperature and precipitation for Finland is
carried out using different versions of the distribution based scaling (DBS)
method. The DBS-adjusted RCM data are used as input of a hydrological model
to simulate changes in discharges of four study catchments in different parts
of Finland. The annual mean discharges and seasonal variation simulated with
the DBS-adjusted temperature and precipitation data are sufficiently close to
observed discharges in the control period 1961–2000 and produce more
realistic projections for mean annual and seasonal changes in discharges than
the uncorrected RCM data. Furthermore, with most scenarios the DBS method
used preserves the temperature and precipitation trends of the uncorrected
RCM data during 1961–2100. However, if the biases in the mean or the
standard deviation of the uncorrected temperatures are large, significant
biases after DBS adjustment may remain or temperature trends may change,
increasing the uncertainty of climate change projections. The DBS method
influences especially the projected seasonal changes in discharges and the
use of uncorrected data can produce unrealistic seasonal discharges and
changes. The projected changes in annual mean discharges are moderate or
small, but seasonal distribution of discharges will change significantly
Environmental specimen bank samples of Pleurozium schreberi and Hylocomium splendens as indicators of the radiation environment at the surface
Effects of using certain tree species in forest regeneration on volume growth, timber yield, and carbon stock of boreal forests in Finland under different CMIP5 projections
201
European UV DataBase (EUVDB) as a repository and quality analyser for solar spectral UV irradiance monitored in Sodankylä
Databases gathering atmospheric data have great potential not only as data
storages but also in serving as platforms for coherent quality assurance
(QA). We report on the flagging system and QA tools designed for and
implemented in the European UV DataBase (EUVDB; <a href="http://uv.fmi.fi/uvdb/" target="_blank">http://uv.fmi.fi/uvdb/</a>)
for measured data on solar spectral UV irradiance. We confine the study on
the data measured by Brewer #037 MkII spectroradiometer in Sodankylä
(67.37° N, 26.63° E) in 1990–2014. The quality indicators
associated with the UV irradiance spectra uploaded into the database are
retrieved from the database and subjected to a statistical analysis. The
study demonstrates the performance of the QA tools of the EUVDB. In addition,
it yields an overall view of the availability and quality of the solar UV
spectra recorded in Sodankylä over a quarter of a century. Over 90 %
of the four main quality indicators are flagged as
GREEN, indicating the
highest achievable quality. For the BLACK flags, denoting data not meeting
the pre-defined requirements, the percentages for all the indicators remain
below 0.12 %