ABSTRACT A regional climate model RegCM3 with a horizontal spacing of 60 km and 18 levels along i... more ABSTRACT A regional climate model RegCM3 with a horizontal spacing of 60 km and 18 levels along its vertical coordinate is applied for simulation of the climate of the European part of Russia. Continuous integration of the model is performed for the period from January 1982 to December 1994. The simulation results are discussed in comparison with the observations available and results of earlier similar studies. The model successfully describes the climate of the region. The model successfully reproduces interannual variations of temperature and precipitation over the region as well as their standard deviations. Space distribution of summer precipitation is also reasonably simulated. A positive bias in the determination of the near-surface air-temperatures characterizes the modeling results over the northern part of the area during the cool season. Also, a positive air-temperature bias characterizes the results over the southern part of the model domain during summer. Precipitation intensity is underestimated during the cool season and overestimated (20–30%) during summer. A positive bias also characterizes the simulated air temperatures during summer over the southern part of the domain. Also, a positive bias characterizes the simulated temperatures during cool season, especially in the northern part of the domain. The systematic defects detected may result from an insufficiently accurate description of the radiative cooling in the model because of an insufficient space resolution and the size of the domain. Overestimated near-surface air temperatures in summer over the southern part of the domain may be caused by insufficient soil moisture in the model and defects in description of the energy balance.
ABSTRACT During last decades of the past century the Mediterranean region was experiencing a nota... more ABSTRACT During last decades of the past century the Mediterranean region was experiencing a notable overall precipitation decline. The period was also characterized by a precipitation rise over northern west Europe as well as a rise (mainly over the south-eastern part of the Mediterranean region) in the frequency and intensity of extreme precipitation events (EPE) during early-spring season. Also noted were significant variations in major teleconnection regimes. To investigate the physical mechanisms involved, globally defined daily NCEP/NCAR reanalysis data for 1961-2000 on precipitation (Prec), integrated water vapor (IWV) and dynamic tropopause pressure (PDT) are analyzed. Frequencies of days with extreme (above 75 percentiles) values of the Prec, PDT and IWV in each month of the 40 year period are determined. Also calculated are the numbers of days per month with the IWV values higher than 10 kg m-2 (IWV10). Linear trends of the characteristics well as their spatial correlations with the time series of major teleconnection indices are determined. Results of the analysis allow explaining observed trends in the Mediterranean precipitation by the corresponding variations in the frequency of the IWV10's. The trends appear to be associated with the global warming process.
Lasting long enough (from several days to months) episodes with extreme precipitation events (ext... more Lasting long enough (from several days to months) episodes with extreme precipitation events (extreme precipitation climate events, EPCE) are quite typical for the Mediterranean region's climate. An analysis of geographical distribution of frequency of occurrence of the EPCE as well as its intraseasonal variation during the Mediterranean rainy season months is performed. Also investigated is the role of large-scale atmospheric dynamics processes over the Mediterranean region in determining the EPCE conditions over the area. An objective methodology based on earlier suggested approach by Carill et al., Clim Dyn, 2008 is adopted to determine frequencies of occurrence of extreme events in several atmospheric characteristics. Daily data on precipitation for 1960-2000 from gridded multiyear dataset National Centers for Environmental Prediction-National Center for Atmospheric Research NCAR-NCEP Reanalysis Project (NNRP) are adopted in the study. A data set with daily data on dynamic ...
Natalia Fedorova 1 , Simon O. Krichak 2 , Vladimir Levit 3 , Maria Helena de Carvalho 4 ,. ... e ... more Natalia Fedorova 1 , Simon O. Krichak 2 , Vladimir Levit 3 , Maria Helena de Carvalho 4 ,. ... e Lifted Index (LI), e, também, foi calculada a energia potencial de convecção ou energia de instabilidade (CAPE, convective available potential energy) (Djuric, 1995 e Vasquez, 1994). ...
During last decades of the past century the Mediterranean region was experiencing a notable overa... more During last decades of the past century the Mediterranean region was experiencing a notable overall precipitation decline. The period was also characterized by a precipitation rise over northern west Europe as well as a rise (mainly over the south-eastern part of the Mediterranean region) in the frequency and intensity of extreme precipitation events (EPE) during early-spring season. Also noted were significant variations in major teleconnection regimes. To investigate the physical mechanisms involved, globally defined daily NCEP/NCAR reanalysis data for 1961-2000 on precipitation (Prec), integrated water vapor (IWV) and dynamic tropopause pressure (PDT) are analyzed. Frequencies of days with extreme (above 75 percentiles) values of the Prec, PDT and IWV in each month of the 40 year period are determined. Also calculated are the numbers of days per month with the IWV values higher than 10 kg m-2 (IWV10). Linear trends of the characteristics well as their spatial correlations with the time series of major teleconnection indices are determined. Results of the analysis allow explaining observed trends in the Mediterranean precipitation by the corresponding variations in the frequency of the IWV10's. The trends appear to be associated with the global warming process.
ABSTRACT A regional climate model RegCM3 with a horizontal spacing of 60 km and 18 levels along i... more ABSTRACT A regional climate model RegCM3 with a horizontal spacing of 60 km and 18 levels along its vertical coordinate is applied for simulation of the climate of the European part of Russia. Continuous integration of the model is performed for the period from January 1982 to December 1994. The simulation results are discussed in comparison with the observations available and results of earlier similar studies. The model successfully describes the climate of the region. The model successfully reproduces interannual variations of temperature and precipitation over the region as well as their standard deviations. Space distribution of summer precipitation is also reasonably simulated. A positive bias in the determination of the near-surface air-temperatures characterizes the modeling results over the northern part of the area during the cool season. Also, a positive air-temperature bias characterizes the results over the southern part of the model domain during summer. Precipitation intensity is underestimated during the cool season and overestimated (20–30%) during summer. A positive bias also characterizes the simulated air temperatures during summer over the southern part of the domain. Also, a positive bias characterizes the simulated temperatures during cool season, especially in the northern part of the domain. The systematic defects detected may result from an insufficiently accurate description of the radiative cooling in the model because of an insufficient space resolution and the size of the domain. Overestimated near-surface air temperatures in summer over the southern part of the domain may be caused by insufficient soil moisture in the model and defects in description of the energy balance.
ABSTRACT During last decades of the past century the Mediterranean region was experiencing a nota... more ABSTRACT During last decades of the past century the Mediterranean region was experiencing a notable overall precipitation decline. The period was also characterized by a precipitation rise over northern west Europe as well as a rise (mainly over the south-eastern part of the Mediterranean region) in the frequency and intensity of extreme precipitation events (EPE) during early-spring season. Also noted were significant variations in major teleconnection regimes. To investigate the physical mechanisms involved, globally defined daily NCEP/NCAR reanalysis data for 1961-2000 on precipitation (Prec), integrated water vapor (IWV) and dynamic tropopause pressure (PDT) are analyzed. Frequencies of days with extreme (above 75 percentiles) values of the Prec, PDT and IWV in each month of the 40 year period are determined. Also calculated are the numbers of days per month with the IWV values higher than 10 kg m-2 (IWV10). Linear trends of the characteristics well as their spatial correlations with the time series of major teleconnection indices are determined. Results of the analysis allow explaining observed trends in the Mediterranean precipitation by the corresponding variations in the frequency of the IWV10's. The trends appear to be associated with the global warming process.
Lasting long enough (from several days to months) episodes with extreme precipitation events (ext... more Lasting long enough (from several days to months) episodes with extreme precipitation events (extreme precipitation climate events, EPCE) are quite typical for the Mediterranean region's climate. An analysis of geographical distribution of frequency of occurrence of the EPCE as well as its intraseasonal variation during the Mediterranean rainy season months is performed. Also investigated is the role of large-scale atmospheric dynamics processes over the Mediterranean region in determining the EPCE conditions over the area. An objective methodology based on earlier suggested approach by Carill et al., Clim Dyn, 2008 is adopted to determine frequencies of occurrence of extreme events in several atmospheric characteristics. Daily data on precipitation for 1960-2000 from gridded multiyear dataset National Centers for Environmental Prediction-National Center for Atmospheric Research NCAR-NCEP Reanalysis Project (NNRP) are adopted in the study. A data set with daily data on dynamic ...
Natalia Fedorova 1 , Simon O. Krichak 2 , Vladimir Levit 3 , Maria Helena de Carvalho 4 ,. ... e ... more Natalia Fedorova 1 , Simon O. Krichak 2 , Vladimir Levit 3 , Maria Helena de Carvalho 4 ,. ... e Lifted Index (LI), e, também, foi calculada a energia potencial de convecção ou energia de instabilidade (CAPE, convective available potential energy) (Djuric, 1995 e Vasquez, 1994). ...
During last decades of the past century the Mediterranean region was experiencing a notable overa... more During last decades of the past century the Mediterranean region was experiencing a notable overall precipitation decline. The period was also characterized by a precipitation rise over northern west Europe as well as a rise (mainly over the south-eastern part of the Mediterranean region) in the frequency and intensity of extreme precipitation events (EPE) during early-spring season. Also noted were significant variations in major teleconnection regimes. To investigate the physical mechanisms involved, globally defined daily NCEP/NCAR reanalysis data for 1961-2000 on precipitation (Prec), integrated water vapor (IWV) and dynamic tropopause pressure (PDT) are analyzed. Frequencies of days with extreme (above 75 percentiles) values of the Prec, PDT and IWV in each month of the 40 year period are determined. Also calculated are the numbers of days per month with the IWV values higher than 10 kg m-2 (IWV10). Linear trends of the characteristics well as their spatial correlations with the time series of major teleconnection indices are determined. Results of the analysis allow explaining observed trends in the Mediterranean precipitation by the corresponding variations in the frequency of the IWV10's. The trends appear to be associated with the global warming process.
Uploads
Papers by Simon Krichak