U. Cortesi - Academia.edu (original) (raw)

Papers by U. Cortesi

FORUM (Far-infrared Outgoing Radiation Understanding and Monitoring) will fly as the ninth ESA's ... more FORUM (Far-infrared Outgoing Radiation Understanding and Monitoring) will fly as the ninth ESA's Earth Explorer mission, and an end-to-end simulator (E2ES) has been developed as a support tool for the mission selection process and the subsequent development phases. The current status of the FORUM E2ES project is presented together with the characterization of the capabilities of a full physics retrieval code applied to FORUM data. We show how the instrument characteristics and the observed scene conditions impact on the spectrum measured by the instrument, accounting for the main sources of error related to the entire acquisition process, and the consequences on the retrieval algorithm. Both homogeneous and heterogeneous case studies are simulated in clear and cloudy conditions, validating the E2ES against appropriate well-established correlative codes. The performed tests show that the performance of the retrieval algorithm is compliant with the project requirements both in clear and cloudy conditions. The far-infrared (FIR) part of the FORUM spectrum is shown to be sensitive to surface emissivity, in dry atmospheric conditions, and to cirrus clouds, resulting in improved performance of the retrieval algorithm in these conditions. The retrieval errors increase with increasing the scene heterogeneity, both in terms of surface characteristics and in terms of fractional cloud cover of the scene.

… down to the earth in the …, 2000

CiteSeerX - Document Details (Isaac Councill, Lee Giles): this paper results of measurements obta... more CiteSeerX - Document Details (Isaac Councill, Lee Giles): this paper results of measurements obtained by the SAFIRE-A instrument (Spectroscopy of the Atmosphere using Far InfraRed Emission - Airborne) during the APE-GAIA (Airborne Polar Experiment Geophysica Aircraft In ...

ESA SP, 2004

A number of in situ and remote sensing techniques for the measurement of upper tropospheric and s... more A number of in situ and remote sensing techniques for the measurement of upper tropospheric and stratospheric O3 content was employed during dedicated experiments of the ESABC programme, aiming at the validation of the ENVISAT chemistry payload. In this paper, we will be focusing on the validation of MIPAS off-line products, by presenting the results of the intercomparison between MIPAS O3 vertical profiles and aircraft and balloon correlative measurements. First priority is given to the validation of processor v4.61 data, but individual results of 2002 and 2003 balloon observations are also compared with MIPAS O3 non operational data. Some general remarks are finally expressed, along with specific recommendation to fully exploit the available ESABC validation dataset.

eprints.bice.rm.cnr.it

Cortesi , Ugo and Del Bianco , Samuele and Gai , Marco and Dinelli , Bianca and Castelli , Elisa ... more Cortesi , Ugo and Del Bianco , Samuele and Gai , Marco and Dinelli , Bianca and Castelli , Elisa and Gerber , Daniel and Oelhaf , Hermann and Woiwode , Wolfgang PREMIER Analysis of Campaign Data ESA-ESTEC Contract 4000101374/NL/10/CT. Project Report. Istituto Fisica ...

Quarterly Journal of the Royal Meteorological Society, 2006

Ozone and temperature profiles from the Michelson Interferometer for Passive Atmospheric Sounding... more Ozone and temperature profiles from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) have been assimilated, using three-dimensional variational assimilation, into a stratosphere-troposphere version of the Met Office numerical weather-prediction system. Analyses are made for the month of September 2002, when there was an unprecedented split in the southern hemisphere polar vortex. The analyses are validated against independent ozone observations from sondes, limb-occultation and total column ozone satellite instruments. Through most of the stratosphere, precision varies from 5 to 15%, and biases are 15% or less of the analysed field. Problems remain in the vortex and below the 60 hPa level, especially at the tropopause where the analyses have too much ozone and poor agreement with independent data. Analysis problems are largely a result of the model rather than the data, giving confidence in the MIPAS ozone retrievals, though there may be a small high bias in MIPAS ozone in the lower stratosphere. Model issues include an excessive Brewer-Dobson circulation, which results both from known problems with the tracer transport scheme and from the data assimilation of dynamical variables. The extreme conditions of the vortex split reveal large differences between existing linear ozone photochemistry schemes. Despite these issues, the ozone analyses are able to successfully describe the ozone hole split and compare well to other studies of this event. Recommendations are made for the further development of the ozone assimilation system.

Optics and Lasers in Engineering, 2002

Fourier transform emission spectroscopy can make an important contribution in the observation of ... more Fourier transform emission spectroscopy can make an important contribution in the observation of the Earth's atmosphere and in the investigation of atmospheric physics and chemistry. In this paper, we report the measurement performances and the result obtained by a Fourier transform spectrometer, named SAFIRE-A (Spectroscopy of the Atmosphere using Far Infrared Emission -Airborne), operating in the far infrared spectral region from limb sounding observation of the atmospheric emission from a high altitude aircraft. After a short review of the advantages of FTS emission limb sounding in comparison with competing techniques and observation geometries, a detailed description of the instrument is given with the result obtained during the APE-GAIA (Airborne Polar Experiment -Geophysica Aircraft In Antarctica) fi eld campaign carried out over the Antarctic Peninsula.

Journal of Quantitative Spectroscopy and Radiative Transfer, 2008

The spectroscopy of the constituents of the Earth's atmosphere that are active in the far infrare... more The spectroscopy of the constituents of the Earth's atmosphere that are active in the far infrared spectral region, among which the water vapour is the main one, have been validated through the analysis of wide-band nadir-looking spectra acquired with the REFIR-PAD (Radiation Explorer in the Far Infrared -Prototype for Applications and Development) Fourier transform spectroradiometer. The spectra, covering from 100 to 1400 cm −1 with a 0.475 cm −1 unapodized resolution, were acquired during a balloon flight performed in a tropical region in 2005. Atmospheric variables, namely water vapour and temperature vertical profiles, were retrieved from the REFIR-PAD data, and the residuals of the fitting are here critically analyzed for the search of systematic effects that can be ascribed to spectroscopic errors. In the spectral interval between 150 and 600 cm −1 no significant inconsistency is detected between the residuals and the measurement uncertainty, proving the good quality of the radiative transfer model and of the HITRAN 2004 spectroscopic database. Significant difference are instead observed when the HITRAN 2000 database is used.

Journal of Quantitative Spectroscopy and Radiative Transfer, 2010

Techniques of data fusion are presently being considered with increasing interest for application... more Techniques of data fusion are presently being considered with increasing interest for application to atmospheric observations from space because of their capability to optimally exploit the complementary information provided by different instruments operating aboard on-going and future ...

Journal of Optics, 1998

ABSTRACT

International Journal of Remote Sensing, 2005

This work presents measurements performed using a multi-input spectroradiometer (GASCOD/A4π) a tw... more This work presents measurements performed using a multi-input spectroradiometer (GASCOD/A4π) a two-channel chromatograph (HAGAR) and a Fourier transform far infrared spectrometer (SAFIRE-A), as part of the scientific instruments on board the of the M55 aircraft, during the APE-GAIA campaign (from 15 September to 14 October, 1999) in Antarctica. The purpose of the work is to investigate the gas concentration distributions during a recovery phase of the reservoir species in the lower stratosphere in the Antarctic spring focusing ion the flight of 23 rd of September 1999. Concentration distributions are presented for NO 2 , N 2 O, O 3 , BrO, ClO, HCl, H 2 O and HNO 3 , during flight time, inside and outside the vortex. The problem of nitrogen compound maxima in the edge region on entering and exiting the vortex was examined when the aircraft was flying on an isentropic surface. Finally the processes of HCl re-conversion and the simultaneous concentration measurements of HNO 3 and H 2 O are examined.

Hydrology and Earth System Sciences, 2013

Precipitation over the Iberian Peninsula (IP) is highly variable and shows large spatial contrast... more Precipitation over the Iberian Peninsula (IP) is highly variable and shows large spatial contrasts between wet mountainous regions to the north, and dry regions in the inland plains and southern areas. In this work, we modelled the relationship between atmospheric circulation weather types (WTs) and monthly precipitation for the wet half of the year (October to May) using a 10 km grid derived from a highdensity dataset for the IP (3030 precipitation series, overall mean density one station each 200 km 2 ). We detected two spatial gradients in the relationship between WTs and precipitation. The percentage of monthly precipitation explained by WTs varies from northwest (higher variance explained) to southeast (lower variance explained). Additionally, in the IP the number of WTs that contribute significantly to monthly precipitation increase systematically from east to west. Generally speaking, the model performance is better to the west than to the east where the WTs approach produce the less accurate results. We applied the WTs modelling approach to reconstruct the long-term precipitation time series for three major stations of Iberia (Lisbon, Madrid, Valencia).

Geophysical Research Letters, 1995

Far infrared spectral features of HBr have been observed in the stratospheric emission spectrum u... more Far infrared spectral features of HBr have been observed in the stratospheric emission spectrum using a balloon borne high resolution Fourier transform spectrometer equipped with a high sensitivity detector specially designed for this purpose. The value of 1.6±0.6 ...

Geophysical Research Letters, 1997

Hydrogen bromide (HBr) is the principal bromine sink species for the ozone loss chemistry induced... more Hydrogen bromide (HBr) is the principal bromine sink species for the ozone loss chemistry induced by brominecontaining gases in the stratosphere. We report a 1994 balloon-based measurement of the daytime stratospherie HBr profile between 20 and 36.5 km altitude. The average concentration result of 1.31 + 0.39 parts per trillion in volume (pptv) and an analysis for the concentration versus altitude profile are consistent with previously reported measurements. These results strengthen the evidence for a significantly higher H]3r concentration than that predicted by current photochemical models which, on the basis of recent kinetics results, do not include significant Hl3r production by the reaction branch, BrO + HO2 --) HBr + 03.

wejump.ifac.cnr.it

Fourier transform spectroscopy in the IR spectral region has been proven to be a valuable tool fo... more Fourier transform spectroscopy in the IR spectral region has been proven to be a valuable tool for the identification and quantification of the composition and the radiative properties of the atmosphere, with special attention to components involved in natural and ...

Atmospheric Chemistry and Physics, 2007

Nitric acid (HNO 3 ) is one of the key products that are operationally retrieved by the European ... more Nitric acid (HNO 3 ) is one of the key products that are operationally retrieved by the European Space Agency (ESA) from the emission spectra measured by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) onboard ENVISAT. The product version 4.61/4.62 for the observation period between July 2002 and March 2004 5 is validated by comparisons with a number of independent observations from groundbased stations, aircraft/balloon campaigns, and satellites. Individual HNO 3 profiles of the ESA MIPAS level-2 product show good agreement with those of MIPAS-B and MIPAS-STR (the balloon and aircraft version of MIPAS, respectively), and the balloonborne infrared spectrometers MkIV and SPIRALE, mostly matching the reference data 10 within the combined instrument error bars. In most cases differences between the correlative measurement pairs are less than 1 ppbv (5-10%) throughout the entire altitude range up to about 38 km (∼6 hPa), and below 0.5 ppbv (15-20% or more) above 30 km (∼17 hPa). However, differences up to 4 ppbv compared to MkIV have been found at high latitudes in December 2002 in the presence of polar stratospheric clouds. The 15 degree of consistency is further largely affected by the temporal and spatial coincidence, and differences of 2 ppbv may be observed between 22 and 26 km (∼50 and 30 hPa) at high latitudes near the vortex boundary, due to large horizontal inhomogeneity of HNO 3 . Similar features are also observed in the mean differences of the MIPAS ESA HNO 3 VMRs with respect to the ground-based FTIR measurements at 20 five stations, aircraft-based SAFIRE-A and ASUR, and the balloon campaign IBEX. The mean relative differences between the MIPAS and FTIR HNO 3 partial columns are within ±2%, comparable to the MIPAS systematic error of ∼2%. For the vertical profiles, the biases between the MIPAS and FTIR data are generally below 10% in the altitudes of 10 to 30 km. The MIPAS and SAFIRE HNO 3 data generally match within 25 their total error bars for the mid and high latitude flights, despite the larger atmospheric inhomogeneities that characterize the measurement scenario at higher latitudes. The MIPAS and ASUR comparison reveals generally good agreements better than 10-13% 5175 ACPD Abstract Introduction Conclusions References Tables Figures Back Close Full Screen / Esc Printer-friendly Version Interactive Discussion

Atmospheric Chemistry and Physics, 2008

Our understanding of global warming depends on the accuracy with which the atmospheric components... more Our understanding of global warming depends on the accuracy with which the atmospheric components that modulate the Earth's radiation budget are known. Many uncertainties still exist as regards the radiative effect of water in the different spectral regions, among which is the far infrared, where very few observations have been made. An assessment is shown of the atmospheric outgoing flux obtained from a balloon-borne platform with wideband spectrallyresolved nadir measurements at the top of the atmosphere over the full spectral range, from 100 to 1400 cm −1 , made by a Fourier transform spectrometer with uncooled detectors. From these measurements, we retrieved 15 pieces of information regarding water vapour and temperature profiles and surface temperature, with a major improvement in our knowledge of water vapour in the upper troposphere. The retrieved atmospheric state made it possible to calculate the emitted radiance also at frequencies and zenith angles that have not been observed and to determine the outgoing spectral radiation flux. This proves that spectrally resolved observations can be used to derive accurate information on the integrated flux. While the retrieved temperature was in agreement with ECMWF analysis, the retrieved water vapour profile differed significantly; depending on the time and the location, the derived flux in the far infrared (20-600 cm −1 ) differed by 2-3.5 W/m 2 from that calculated using ECMWF. The error with which the far infrared flux is determined by REFIR-PAD is about 0.4 W/m 2 and is caused mainly by calibration uncertainties, while detector noise has a negligible effect. This proves that uncooled detectors are adequate for top-of-the-atmosphere radiometry.

Atmospheric Chemistry and Physics, 2008

MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) is operating on the ENVIronment... more MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) is operating on the ENVIronmental SATellite (ENVISAT) since March 2002. After two years of nearly continuous limb scanning measurements, at the end of March 2004, the instrument was stopped due to problems with the mirror drive of the interferometer. Operations 20 reduced-resolution measurements is comparable or better than that obtained from the full-resolution dataset. The only significant change in MIPAS performances is observed at pressures around 2 hPa, where the relative bias of the instruments increases by a factor of 2 from the Abstract ACPD 8, 797-825, 2008 Abstract ACPD 8, 797-825, 2008 Abstract ACPD 8, 797-825, 2008 Abstract ACPD 8, 797-825, 2008 Abstract ACPD 8, 797-825, 2008 Abstract 8, 797-825, 2008 Abstract ACPD 8, 797-825, 2008 Abstract 8, 797-825, 2008 Abstract 8, 797-825, 2008 Abstract ACPD 8, 797-825, 2008 Abstract 8, 797-825, 2008 Abstract 813 ACPD 8, 797-825, 2008 Abstract 8, 797-825, 2008

Atmospheric Chemistry and Physics, 2009

Payan, S.; Camy-Peyret, C.; Oelhaf, H.; Wetzel, G.; Maucher, G.; Keim, C.; Pirre, M.; Huret, N.; ... more Payan, S.; Camy-Peyret, C.; Oelhaf, H.; Wetzel, G.; Maucher, G.; Keim, C.; Pirre, M.; Huret, N.; Engel, A.; Volk, MC; Kuellmann, H.; Kuttippurath, J.; Cortesi, U.; Bianchini, G.; Mencaraglia, F.; Raspollini, P.; Redaelli, G.; Vigouroux, C.; de Mazière, M.; Mikuteit, S.; Blumenstock, T.; ...

Atmospheric Chemistry and Physics, 2006

Atmospheric Chemistry and Physics, 2010

The combination of data obtained with different sensors (data fusion) is a powerful technique tha... more The combination of data obtained with different sensors (data fusion) is a powerful technique that can provide target products of the best quality in terms of precision and accuracy, as well as spatial and temporal coverage and resolution. In this paper the results are presented of the data fusion of measurements of ozone vertical profile performed by two space-borne interferometers (IASI on METOP and MIPAS on ENVISAT) using the new measurement-spacesolution method. With this method both the loss of information due to interpolation and the propagation of possible biases (caused by a priori information) are avoided. The data fusion products are characterized by means of retrieval errors, information gain, averaging kernels and number of degrees of freedom. The analysis is performed both on simulated and real measurements and the results demonstrate and quantify the improvement of data fusion products with respect to measurements of a single instrument.

FORUM (Far-infrared Outgoing Radiation Understanding and Monitoring) will fly as the ninth ESA's ... more FORUM (Far-infrared Outgoing Radiation Understanding and Monitoring) will fly as the ninth ESA's Earth Explorer mission, and an end-to-end simulator (E2ES) has been developed as a support tool for the mission selection process and the subsequent development phases. The current status of the FORUM E2ES project is presented together with the characterization of the capabilities of a full physics retrieval code applied to FORUM data. We show how the instrument characteristics and the observed scene conditions impact on the spectrum measured by the instrument, accounting for the main sources of error related to the entire acquisition process, and the consequences on the retrieval algorithm. Both homogeneous and heterogeneous case studies are simulated in clear and cloudy conditions, validating the E2ES against appropriate well-established correlative codes. The performed tests show that the performance of the retrieval algorithm is compliant with the project requirements both in clear and cloudy conditions. The far-infrared (FIR) part of the FORUM spectrum is shown to be sensitive to surface emissivity, in dry atmospheric conditions, and to cirrus clouds, resulting in improved performance of the retrieval algorithm in these conditions. The retrieval errors increase with increasing the scene heterogeneity, both in terms of surface characteristics and in terms of fractional cloud cover of the scene.

… down to the earth in the …, 2000

CiteSeerX - Document Details (Isaac Councill, Lee Giles): this paper results of measurements obta... more CiteSeerX - Document Details (Isaac Councill, Lee Giles): this paper results of measurements obtained by the SAFIRE-A instrument (Spectroscopy of the Atmosphere using Far InfraRed Emission - Airborne) during the APE-GAIA (Airborne Polar Experiment Geophysica Aircraft In ...

ESA SP, 2004

A number of in situ and remote sensing techniques for the measurement of upper tropospheric and s... more A number of in situ and remote sensing techniques for the measurement of upper tropospheric and stratospheric O3 content was employed during dedicated experiments of the ESABC programme, aiming at the validation of the ENVISAT chemistry payload. In this paper, we will be focusing on the validation of MIPAS off-line products, by presenting the results of the intercomparison between MIPAS O3 vertical profiles and aircraft and balloon correlative measurements. First priority is given to the validation of processor v4.61 data, but individual results of 2002 and 2003 balloon observations are also compared with MIPAS O3 non operational data. Some general remarks are finally expressed, along with specific recommendation to fully exploit the available ESABC validation dataset.

eprints.bice.rm.cnr.it

Cortesi , Ugo and Del Bianco , Samuele and Gai , Marco and Dinelli , Bianca and Castelli , Elisa ... more Cortesi , Ugo and Del Bianco , Samuele and Gai , Marco and Dinelli , Bianca and Castelli , Elisa and Gerber , Daniel and Oelhaf , Hermann and Woiwode , Wolfgang PREMIER Analysis of Campaign Data ESA-ESTEC Contract 4000101374/NL/10/CT. Project Report. Istituto Fisica ...

Quarterly Journal of the Royal Meteorological Society, 2006

Ozone and temperature profiles from the Michelson Interferometer for Passive Atmospheric Sounding... more Ozone and temperature profiles from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) have been assimilated, using three-dimensional variational assimilation, into a stratosphere-troposphere version of the Met Office numerical weather-prediction system. Analyses are made for the month of September 2002, when there was an unprecedented split in the southern hemisphere polar vortex. The analyses are validated against independent ozone observations from sondes, limb-occultation and total column ozone satellite instruments. Through most of the stratosphere, precision varies from 5 to 15%, and biases are 15% or less of the analysed field. Problems remain in the vortex and below the 60 hPa level, especially at the tropopause where the analyses have too much ozone and poor agreement with independent data. Analysis problems are largely a result of the model rather than the data, giving confidence in the MIPAS ozone retrievals, though there may be a small high bias in MIPAS ozone in the lower stratosphere. Model issues include an excessive Brewer-Dobson circulation, which results both from known problems with the tracer transport scheme and from the data assimilation of dynamical variables. The extreme conditions of the vortex split reveal large differences between existing linear ozone photochemistry schemes. Despite these issues, the ozone analyses are able to successfully describe the ozone hole split and compare well to other studies of this event. Recommendations are made for the further development of the ozone assimilation system.

Optics and Lasers in Engineering, 2002

Fourier transform emission spectroscopy can make an important contribution in the observation of ... more Fourier transform emission spectroscopy can make an important contribution in the observation of the Earth's atmosphere and in the investigation of atmospheric physics and chemistry. In this paper, we report the measurement performances and the result obtained by a Fourier transform spectrometer, named SAFIRE-A (Spectroscopy of the Atmosphere using Far Infrared Emission -Airborne), operating in the far infrared spectral region from limb sounding observation of the atmospheric emission from a high altitude aircraft. After a short review of the advantages of FTS emission limb sounding in comparison with competing techniques and observation geometries, a detailed description of the instrument is given with the result obtained during the APE-GAIA (Airborne Polar Experiment -Geophysica Aircraft In Antarctica) fi eld campaign carried out over the Antarctic Peninsula.

Journal of Quantitative Spectroscopy and Radiative Transfer, 2008

The spectroscopy of the constituents of the Earth's atmosphere that are active in the far infrare... more The spectroscopy of the constituents of the Earth's atmosphere that are active in the far infrared spectral region, among which the water vapour is the main one, have been validated through the analysis of wide-band nadir-looking spectra acquired with the REFIR-PAD (Radiation Explorer in the Far Infrared -Prototype for Applications and Development) Fourier transform spectroradiometer. The spectra, covering from 100 to 1400 cm −1 with a 0.475 cm −1 unapodized resolution, were acquired during a balloon flight performed in a tropical region in 2005. Atmospheric variables, namely water vapour and temperature vertical profiles, were retrieved from the REFIR-PAD data, and the residuals of the fitting are here critically analyzed for the search of systematic effects that can be ascribed to spectroscopic errors. In the spectral interval between 150 and 600 cm −1 no significant inconsistency is detected between the residuals and the measurement uncertainty, proving the good quality of the radiative transfer model and of the HITRAN 2004 spectroscopic database. Significant difference are instead observed when the HITRAN 2000 database is used.

Journal of Quantitative Spectroscopy and Radiative Transfer, 2010

Techniques of data fusion are presently being considered with increasing interest for application... more Techniques of data fusion are presently being considered with increasing interest for application to atmospheric observations from space because of their capability to optimally exploit the complementary information provided by different instruments operating aboard on-going and future ...

Journal of Optics, 1998

ABSTRACT

International Journal of Remote Sensing, 2005

This work presents measurements performed using a multi-input spectroradiometer (GASCOD/A4π) a tw... more This work presents measurements performed using a multi-input spectroradiometer (GASCOD/A4π) a two-channel chromatograph (HAGAR) and a Fourier transform far infrared spectrometer (SAFIRE-A), as part of the scientific instruments on board the of the M55 aircraft, during the APE-GAIA campaign (from 15 September to 14 October, 1999) in Antarctica. The purpose of the work is to investigate the gas concentration distributions during a recovery phase of the reservoir species in the lower stratosphere in the Antarctic spring focusing ion the flight of 23 rd of September 1999. Concentration distributions are presented for NO 2 , N 2 O, O 3 , BrO, ClO, HCl, H 2 O and HNO 3 , during flight time, inside and outside the vortex. The problem of nitrogen compound maxima in the edge region on entering and exiting the vortex was examined when the aircraft was flying on an isentropic surface. Finally the processes of HCl re-conversion and the simultaneous concentration measurements of HNO 3 and H 2 O are examined.

Hydrology and Earth System Sciences, 2013

Precipitation over the Iberian Peninsula (IP) is highly variable and shows large spatial contrast... more Precipitation over the Iberian Peninsula (IP) is highly variable and shows large spatial contrasts between wet mountainous regions to the north, and dry regions in the inland plains and southern areas. In this work, we modelled the relationship between atmospheric circulation weather types (WTs) and monthly precipitation for the wet half of the year (October to May) using a 10 km grid derived from a highdensity dataset for the IP (3030 precipitation series, overall mean density one station each 200 km 2 ). We detected two spatial gradients in the relationship between WTs and precipitation. The percentage of monthly precipitation explained by WTs varies from northwest (higher variance explained) to southeast (lower variance explained). Additionally, in the IP the number of WTs that contribute significantly to monthly precipitation increase systematically from east to west. Generally speaking, the model performance is better to the west than to the east where the WTs approach produce the less accurate results. We applied the WTs modelling approach to reconstruct the long-term precipitation time series for three major stations of Iberia (Lisbon, Madrid, Valencia).

Geophysical Research Letters, 1995

Far infrared spectral features of HBr have been observed in the stratospheric emission spectrum u... more Far infrared spectral features of HBr have been observed in the stratospheric emission spectrum using a balloon borne high resolution Fourier transform spectrometer equipped with a high sensitivity detector specially designed for this purpose. The value of 1.6±0.6 ...

Geophysical Research Letters, 1997

Hydrogen bromide (HBr) is the principal bromine sink species for the ozone loss chemistry induced... more Hydrogen bromide (HBr) is the principal bromine sink species for the ozone loss chemistry induced by brominecontaining gases in the stratosphere. We report a 1994 balloon-based measurement of the daytime stratospherie HBr profile between 20 and 36.5 km altitude. The average concentration result of 1.31 + 0.39 parts per trillion in volume (pptv) and an analysis for the concentration versus altitude profile are consistent with previously reported measurements. These results strengthen the evidence for a significantly higher H]3r concentration than that predicted by current photochemical models which, on the basis of recent kinetics results, do not include significant Hl3r production by the reaction branch, BrO + HO2 --) HBr + 03.

wejump.ifac.cnr.it

Fourier transform spectroscopy in the IR spectral region has been proven to be a valuable tool fo... more Fourier transform spectroscopy in the IR spectral region has been proven to be a valuable tool for the identification and quantification of the composition and the radiative properties of the atmosphere, with special attention to components involved in natural and ...

Atmospheric Chemistry and Physics, 2007

Nitric acid (HNO 3 ) is one of the key products that are operationally retrieved by the European ... more Nitric acid (HNO 3 ) is one of the key products that are operationally retrieved by the European Space Agency (ESA) from the emission spectra measured by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) onboard ENVISAT. The product version 4.61/4.62 for the observation period between July 2002 and March 2004 5 is validated by comparisons with a number of independent observations from groundbased stations, aircraft/balloon campaigns, and satellites. Individual HNO 3 profiles of the ESA MIPAS level-2 product show good agreement with those of MIPAS-B and MIPAS-STR (the balloon and aircraft version of MIPAS, respectively), and the balloonborne infrared spectrometers MkIV and SPIRALE, mostly matching the reference data 10 within the combined instrument error bars. In most cases differences between the correlative measurement pairs are less than 1 ppbv (5-10%) throughout the entire altitude range up to about 38 km (∼6 hPa), and below 0.5 ppbv (15-20% or more) above 30 km (∼17 hPa). However, differences up to 4 ppbv compared to MkIV have been found at high latitudes in December 2002 in the presence of polar stratospheric clouds. The 15 degree of consistency is further largely affected by the temporal and spatial coincidence, and differences of 2 ppbv may be observed between 22 and 26 km (∼50 and 30 hPa) at high latitudes near the vortex boundary, due to large horizontal inhomogeneity of HNO 3 . Similar features are also observed in the mean differences of the MIPAS ESA HNO 3 VMRs with respect to the ground-based FTIR measurements at 20 five stations, aircraft-based SAFIRE-A and ASUR, and the balloon campaign IBEX. The mean relative differences between the MIPAS and FTIR HNO 3 partial columns are within ±2%, comparable to the MIPAS systematic error of ∼2%. For the vertical profiles, the biases between the MIPAS and FTIR data are generally below 10% in the altitudes of 10 to 30 km. The MIPAS and SAFIRE HNO 3 data generally match within 25 their total error bars for the mid and high latitude flights, despite the larger atmospheric inhomogeneities that characterize the measurement scenario at higher latitudes. The MIPAS and ASUR comparison reveals generally good agreements better than 10-13% 5175 ACPD Abstract Introduction Conclusions References Tables Figures Back Close Full Screen / Esc Printer-friendly Version Interactive Discussion

Atmospheric Chemistry and Physics, 2008

Our understanding of global warming depends on the accuracy with which the atmospheric components... more Our understanding of global warming depends on the accuracy with which the atmospheric components that modulate the Earth's radiation budget are known. Many uncertainties still exist as regards the radiative effect of water in the different spectral regions, among which is the far infrared, where very few observations have been made. An assessment is shown of the atmospheric outgoing flux obtained from a balloon-borne platform with wideband spectrallyresolved nadir measurements at the top of the atmosphere over the full spectral range, from 100 to 1400 cm −1 , made by a Fourier transform spectrometer with uncooled detectors. From these measurements, we retrieved 15 pieces of information regarding water vapour and temperature profiles and surface temperature, with a major improvement in our knowledge of water vapour in the upper troposphere. The retrieved atmospheric state made it possible to calculate the emitted radiance also at frequencies and zenith angles that have not been observed and to determine the outgoing spectral radiation flux. This proves that spectrally resolved observations can be used to derive accurate information on the integrated flux. While the retrieved temperature was in agreement with ECMWF analysis, the retrieved water vapour profile differed significantly; depending on the time and the location, the derived flux in the far infrared (20-600 cm −1 ) differed by 2-3.5 W/m 2 from that calculated using ECMWF. The error with which the far infrared flux is determined by REFIR-PAD is about 0.4 W/m 2 and is caused mainly by calibration uncertainties, while detector noise has a negligible effect. This proves that uncooled detectors are adequate for top-of-the-atmosphere radiometry.

Atmospheric Chemistry and Physics, 2008

MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) is operating on the ENVIronment... more MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) is operating on the ENVIronmental SATellite (ENVISAT) since March 2002. After two years of nearly continuous limb scanning measurements, at the end of March 2004, the instrument was stopped due to problems with the mirror drive of the interferometer. Operations 20 reduced-resolution measurements is comparable or better than that obtained from the full-resolution dataset. The only significant change in MIPAS performances is observed at pressures around 2 hPa, where the relative bias of the instruments increases by a factor of 2 from the Abstract ACPD 8, 797-825, 2008 Abstract ACPD 8, 797-825, 2008 Abstract ACPD 8, 797-825, 2008 Abstract ACPD 8, 797-825, 2008 Abstract ACPD 8, 797-825, 2008 Abstract 8, 797-825, 2008 Abstract ACPD 8, 797-825, 2008 Abstract 8, 797-825, 2008 Abstract 8, 797-825, 2008 Abstract ACPD 8, 797-825, 2008 Abstract 8, 797-825, 2008 Abstract 813 ACPD 8, 797-825, 2008 Abstract 8, 797-825, 2008

Atmospheric Chemistry and Physics, 2009

Payan, S.; Camy-Peyret, C.; Oelhaf, H.; Wetzel, G.; Maucher, G.; Keim, C.; Pirre, M.; Huret, N.; ... more Payan, S.; Camy-Peyret, C.; Oelhaf, H.; Wetzel, G.; Maucher, G.; Keim, C.; Pirre, M.; Huret, N.; Engel, A.; Volk, MC; Kuellmann, H.; Kuttippurath, J.; Cortesi, U.; Bianchini, G.; Mencaraglia, F.; Raspollini, P.; Redaelli, G.; Vigouroux, C.; de Mazière, M.; Mikuteit, S.; Blumenstock, T.; ...

Atmospheric Chemistry and Physics, 2006

Atmospheric Chemistry and Physics, 2010

The combination of data obtained with different sensors (data fusion) is a powerful technique tha... more The combination of data obtained with different sensors (data fusion) is a powerful technique that can provide target products of the best quality in terms of precision and accuracy, as well as spatial and temporal coverage and resolution. In this paper the results are presented of the data fusion of measurements of ozone vertical profile performed by two space-borne interferometers (IASI on METOP and MIPAS on ENVISAT) using the new measurement-spacesolution method. With this method both the loss of information due to interpolation and the propagation of possible biases (caused by a priori information) are avoided. The data fusion products are characterized by means of retrieval errors, information gain, averaging kernels and number of degrees of freedom. The analysis is performed both on simulated and real measurements and the results demonstrate and quantify the improvement of data fusion products with respect to measurements of a single instrument.