D. Papanastasopoulos - Academia.edu (original) (raw)
I am a research engineer in the field of environmental engineering
less
Uploads
Papers by D. Papanastasopoulos
Research at Imperial College developed a methodology to extract time-space dependent hydrological... more Research at Imperial College developed a methodology to extract time-space dependent hydrological parameters form Remote Sensing data in order to predict land surface temperature from satellite observations. Time series of actual ET were estimated using both the SVAT model and the water balance model. The comparison of cumulative ET between the two different methods shows a good agreement and validates the developed parameterisation. Plant growth as it is described by the temporal signal of SAR data and interpreted by the optical data for the presence and status of vegetation in a distributed manner over the entire area, is proven to be very close to the traditionally reliable method of estimating losses using a hydrologic engineering model calibrated against hourly river flow data. The cumbersome process of selecting parameters for every discredited modelling unit has been replaced by a simple automated procedure after converting the SAR temporal signal into a dimensionless growth factor. Different runs of the system of SVAT columns employing different functions linking the derived growth factor and biophysical parameters, as well as, different sets of maximum and minimum values for the time dependent plant growth parameters were used.
Journal of Hydrology, 2001
ABSTRACT Significance of predictions concerning the climate change impact on basin hydrology in c... more ABSTRACT Significance of predictions concerning the climate change impact on basin hydrology in case of doubled CO2 concentration in the atmosphere (2×CO2-case) is investigated within the context of a case study for the Mesohora basin in Greece. Circulation patterns (CPs) characterizing the weather in the region are defined based on wind direction and on barometric conditions and the modification of the large-scale atmospheric variables (geopotential height, occurrence probability and duration of CPs) in 2×CO2-case is estimated. The effect of the atmospheric-variables modification on temperature and precipitation on basin scale is predicted by means of a semiempirical, purely circulation-based downscaling model. Temperature modification in 2×CO2-case has been found to be significant for eight months of the year with a maximal increase of mean monthly temperature approximately 2°C. For precipitation, significant change has been predicted for one of the precipitation stations considered. Owing to the fact that this precipitation change does not influence mean precipitation of the basin, climate change impact on basin runoff has been investigated only for temperature effects. For this purpose a hydrological model has been used. It has been found that the error of hydrologic model is significantly larger than climate change impact so that modifications of the river basin hydrology for the 2×CO2-case can be hardly predicted.
Research at Imperial College developed a methodology to extract time-space dependent hydrological... more Research at Imperial College developed a methodology to extract time-space dependent hydrological parameters form Remote Sensing data in order to predict land surface temperature from satellite observations. Time series of actual ET were estimated using both the SVAT model and the water balance model. The comparison of cumulative ET between the two different methods shows a good agreement and validates the developed parameterisation. Plant growth as it is described by the temporal signal of SAR data and interpreted by the optical data for the presence and status of vegetation in a distributed manner over the entire area, is proven to be very close to the traditionally reliable method of estimating losses using a hydrologic engineering model calibrated against hourly river flow data. The cumbersome process of selecting parameters for every discredited modelling unit has been replaced by a simple automated procedure after converting the SAR temporal signal into a dimensionless growth factor. Different runs of the system of SVAT columns employing different functions linking the derived growth factor and biophysical parameters, as well as, different sets of maximum and minimum values for the time dependent plant growth parameters were used.
Journal of Hydrology, 2001
ABSTRACT Significance of predictions concerning the climate change impact on basin hydrology in c... more ABSTRACT Significance of predictions concerning the climate change impact on basin hydrology in case of doubled CO2 concentration in the atmosphere (2×CO2-case) is investigated within the context of a case study for the Mesohora basin in Greece. Circulation patterns (CPs) characterizing the weather in the region are defined based on wind direction and on barometric conditions and the modification of the large-scale atmospheric variables (geopotential height, occurrence probability and duration of CPs) in 2×CO2-case is estimated. The effect of the atmospheric-variables modification on temperature and precipitation on basin scale is predicted by means of a semiempirical, purely circulation-based downscaling model. Temperature modification in 2×CO2-case has been found to be significant for eight months of the year with a maximal increase of mean monthly temperature approximately 2°C. For precipitation, significant change has been predicted for one of the precipitation stations considered. Owing to the fact that this precipitation change does not influence mean precipitation of the basin, climate change impact on basin runoff has been investigated only for temperature effects. For this purpose a hydrological model has been used. It has been found that the error of hydrologic model is significantly larger than climate change impact so that modifications of the river basin hydrology for the 2×CO2-case can be hardly predicted.