Papers by Manuel Lopez-Puertas
Atmospheric Chemistry and Physics, 2008
Satellite observations show that the enormous solar proton events (SPEs) in October-November 2003... more Satellite observations show that the enormous solar proton events (SPEs) in October-November 2003 had significant effects on the composition of the stratosphere and mesosphere in the polar regions. After the October-November 2003 SPEs and in early 2004 significant enhancements of NO x (=NO+NO 2 ) in the upper stratosphere 5 and lower mesosphere in the Northern Hemisphere were observed by several satellite instruments. Here we present global full chemistry calculations performed with the CLaMS model to study the impact of mesospheric NO x intrusions on Arctic polar ozone loss processes in the stratosphere. Several model simulations are preformed with different upper boundary conditions for NO x at 2000 K potential temperature (≈50 km 10 altitude). In our study we focus on the impact of the non-local production of NO x which means the downward transport of enhanced NO x from the mesosphere in the stratosphere. The local production of NO x in the stratosphere is neglected. Our findings show that intrusions of mesospheric air into the stratosphere, transporting high burdens of NO x , affect the composition of the Arctic polar region down to about 400 K 15 (≈17 -18 km). We compare our simulated NO x and O 3 mixing ratios with satellite observations by ACE-FTS and MIPAS processed at IMK/IAA and derive an upper limit for the ozone loss caused by enhanced mesospheric NO x . Our findings show that in the Arctic polar vortex (Equivalent Lat.> 70 • N) the accumulated column ozone loss between 350 -2000 K potential temperature (≈14 -50 km altitude) caused by the SPEs
Advances in Space Research, 2001
The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) is a high-resolution limb s... more The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) is a high-resolution limb sounder on board the European polar platform ENVISAT, scheduled to be launched in 2001. A large number of atmospheric trace gases relevant to stratospheric ozone chemistry and global change are expected to be retrieved from the IR spectra covering a wide spectral range. While operational data analysis under responsibility of the European Space Agency is limited to conditions of local thermodynamic equilibrium (LTE), the analysis of limb radiances affected by non-LTE is left to scientific institutions. In this paper we present an innovative non-LTE retrieval method as part of the MIPAS semi-operational data processor developed at the Institut ffir Meteorologic und Klimaforschung (IMK). The new approach enables the treatment of vibrational, rotational, and spin non-LTE as well as a dependence of the non-LTE state distribution on the retrieval target quantities. In a case study, the method has been tested for its application to the non-LTE analysis of 5.3 pm MIPAS radiances. The fundamental to-vibrational band of nitric oxide emitting at 5.3 pm shows strong non-LTE effects arising from vibrational excitation of stratospheric NO and superposed thermospheric non-LTE emissions. A conventional non-LTE retrieval approach using ab initio vibrational temperatures of NO cannot be applied due to rotational and spin non-LTE in the thermosphere, and the dependence of stratospheric vibrational temperatures on the NO abundance itself. The ability of the developed non-LTE inversion tool to retrieve stratospheric NO abundances is demonstrated by retrieval simulations. The further application of this method to the simultaneous retrieval of NO and kinetic temperature in the thermosphere and the retrieval of important non-LTE process parameters has also been tested.
Atmospheric Chemistry and Physics, 2012
Applied Optics, 2000
For data analysis of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) atmosp... more For data analysis of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) atmospheric limb emission spectroscopic experiment on Environmental Satellite microwindows, i.e., small spectral regions for data analysis, have been defined and optimized. A novel optimization scheme has been developed for this purpose that adjusts microwindow boundaries such that the total retrieval error with respect to measurement noise, parameter uncertainties, and systematic errors is minimized. Dedicated databases that contain optimized microwindows for retrieval of vertical profiles of pressure and temperature, H2O, O3, HNO3, CH4, N2O, and NO2 have been generated. Furthermore, a tool for optimal selection of subsets of predefined microwindows for specific retrieval situations has been provided. This tool can be used further for estimating total retrieval errors for a selected microwindow subset. It has been shown by use of this tool that an altitude-dependent definition of microwindows is superior to an altitude-independent definition. For computational efficiency a dedicated microwindow-related list of spectral lines has been defined that contains only those spectral lines that are of relevance for MIPAS limb sounding observations.
Advances in Space Research, 2005
Vertical profiles of O 3 and NO 2 abundances from the atmospheric instruments GOMOS (Global Ozone... more Vertical profiles of O 3 and NO 2 abundances from the atmospheric instruments GOMOS (Global Ozone Monitoring by the Occultation of Stars), MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) and SCIAMACHY (Scanning Imaging Spectrometer for Atmospheric Chartography) all on-board the recently launched European Space Agency (ESA) Environmental Satellite (ENVISAT) are intercompared. These comparisons contribute to the validation of these data products by detecting systematic deviations, for example, wrong tangent height determinations, spectroscopic errors, and others. The cross comparison includes GOMOS data products retrieved by the GOMOS prototype processor from ACRI (Sophia Antipolis, France), the scientific SCIAMACHY data products from the Institute of Environmental Physics at University of Bremen (IUP) and the scientific MIPAS data products from the Institute for Meteorology and Climate Research in Karlsruhe (IMK) and Institute of Astrophysics in Andalusia (IAA). Coincident measurements were identified by limiting the time difference to 100 min (duration of one orbit) and less than 500 km between two observation points. When lower stratospheric ozone is strongly depleted during polar spring, a homogeneity condition was further imposed on the satellite measurements by requiring an upper limit on the potential vorticity difference at the 475 K isentrope between both observations. Since geographically coincident NO 2 measurements of the three instruments are performed during different times of the day and NO 2 has a rather strong diurnal variability, matches of NO 2 profiles were compared only where the solar zenith angle difference was below 5°. First results of the cross comparison show an agreement within 15% between 21 and 40 km altitude for O 3 profiles and an agreement within 20% between 27 and 40 km altitude for NO 2 profiles among the GOMOS, MIPAS and SCIAMACHY measurements.
Atmospheric Chemistry and Physics, 2008
Solar eruptions sometimes produce protons, which impact the Earth's atmosphere. These solar proto... more Solar eruptions sometimes produce protons, which impact the Earth's atmosphere. These solar proton events (SPEs) generally last a few days and produce high energy particles that precipitate into the Earth's atmosphere. The protons cause ionization and dissociation processes that ultimately lead to an enhancement of odd-hydrogen and oddnitrogen in the polar cap regions (>60 • geomagnetic latitude). We have used the Whole Atmosphere Community Climate Model (WACCM3) to study the atmospheric impact of SPEs over the period 1963-2005. The very largest SPEs were found to be the most important and caused atmospheric effects that lasted several months after the events. We present the short-and medium-term (days to a few months) atmospheric influence of the four largest SPEs in the past ) as computed by WACCM3 and observed by satellite instruments. Polar mesospheric NO x (NO+NO 2 ) increased by over 50 ppbv and mesospheric ozone decreased by over 30% during these very large SPEs. Changes in HNO 3 , N 2 O 5 , ClONO 2 , HOCl, and ClO were indirectly caused by the very large SPEs in October-November 2003, were simulated by WACCM3, and previously measured by Envisat Michelson Interferometer for Passive Atmospheric Sounding (MIPAS). WACCM3 output was also represented by sampling with the MIPAS averaging kernel for a more valid comparison. Although qualitatively similar, there are discrepancies between the model and measurement with WACCM3 predicted HNO 3 and ClONO 2 enhancements being smaller than measured and N 2 O 5 enhancements being larger than measured. The HOCl enhancements were fairly Correspondence to: C. H. Jackman ([email protected]) similar in amounts and temporal variation in WACCM3 and MIPAS. WACCM3 simulated ClO decreases below 50 km, whereas MIPAS mainly observed increases, a very perplexing difference. Upper stratospheric and lower mesospheric NO x increased by over 10 ppbv and was transported during polar night down to the middle stratosphere in several weeks past the SPE. The WACCM3 simulations confirmed the SH HALOE observations of enhanced NO x in September 2000 as a result of the July 2000 SPE and the NH SAGE II observations of enhanced NO 2 in March 1990 as a result of the October 1989 SPEs.
Advances in Space Research, 2005
With the successful launch of the European Space AgencyÕs Envisat satellite new possibilities for... more With the successful launch of the European Space AgencyÕs Envisat satellite new possibilities for global night-time measurements of middle atmospheric ozone have emerged. The GOMOS and MIPAS instruments on board Envisat are able to measure ozone in both day and night conditions, which is especially important in the mesosphere where the diurnal variations of ozone are substantial. In this paper, we present a comparison of MIPAS and GOMOS night-time measurements. We show individual measurement profiles as well as statistical average profiles of stratospheric and mesospheric ozone from both instruments. Our conclusion is that the two instruments are generally in a good agreement throughout the middle atmosphere.
Comptes Rendus Physique, 2005
Atmospheric Chemistry and Physics, 2012
Sudden changes in stratospheric chlorine species in the polar northern atmosphere, caused by the ... more Sudden changes in stratospheric chlorine species in the polar northern atmosphere, caused by the Solar Proton Events (SPEs) of 17 and 20 January 2005, have been investigated and compared with version 4 of the Whole Atmosphere Community Climate Model (WACCM4). We used Aura Microwave Limb Sounder (MLS) measurements to 5 monitor the variability of ClO, HCl, HOCl and Michelson Interferometer for Passive Atmospheric Sounder (MIPAS) on ENVISAT to retrieve ClONO 2 . SPE-induced chlorine activation has been identified. HCl decrease occurred at nearly all the investigated altitudes with the lowest values (of less than 0.25 ppbv) on 21 January. HOCl was found to be the main active chlorine species under nighttime conditions (with increases 10 of more than 0.2 ppbv) whereas both HOCl and ClO enhancements (about 0.1 ppbv) have been observed at the polar night terminator. Further, small ClO decreases (of less than 0.1 ppbv) and ClONO 2 enhancements (about 0.2 ppbv) have been observed at higher latitudes (i.e., at nighttime) roughly above 2 hPa.
Atmospheric Chemistry and Physics, 2012
An extensive observational data set, consisting of more than 106 SF6 vertical profiles distribute... more An extensive observational data set, consisting of more than 106 SF6 vertical profiles distributed globally from MIPAS measurements has been condensed into monthly zonal means of mean age of air for the period September 2002 to January 2010, binned at 10° latitude and 1-2 km altitude. The data were analysed with respect to their temporal variation by fitting a regression
Journal of Geophysical Research, 2003
1] The functionality and characteristics of six different data processors (i.e., retrieval codes ... more 1] The functionality and characteristics of six different data processors (i.e., retrieval codes in their actual software and hardware environment) for analysis of high-resolution limb emission infrared spectra recorded by the space-borne Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) have been validated by means of a blind test retrieval experiment based on synthetic spectra. For this purpose a self-consistent set of atmospheric state parameters, including pressure, temperature, vibrational temperatures, and abundances of trace gases and aerosols, has been generated and used as input for radiative transfer calculations for MIPAS measurement geometry and configuration. These spectra were convolved with the MIPAS field of view, spectrally degraded by the MIPAS instrument line shape, and, finally, superimposed with synthetic measurement noise. These synthetic MIPAS measurements were distributed among the participants of the project ''Advanced MIPAS level-2 data analysis'' (AMIL2DA), who performed temperature and species abundance profile retrievals by inverse radiative transfer calculations. While the retrieved profiles of atmospheric state parameters reflect some characteristics of the individual data processors, it was shown that all the data processors under investigation are capable of producing reliable results in the sense that deviations of retrieved results from the reference profiles are within the margin that is consistent with analytical error estimation.
Geophysical Research Letters, 2008
Journal of Atmospheric and Solar-Terrestrial Physics, 2006
Daytime mesospheric limb emission spectra of ozone in the 4:8 mm regime are analyzed with respect... more Daytime mesospheric limb emission spectra of ozone in the 4:8 mm regime are analyzed with respect to vibrational excitation and relaxation processes. The data, which was obtained by the MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) instrument on board ESA's Environmental Satellite, is simulated by means of a non-local thermodynamic equilibrium (non-LTE) model utilizing O 3 -abundance, temperature, and pressure data from simultaneous retrievals in other spectral regions. The vibrational states of ozone depart from LTE due to the absorption of radiation from the lower atmosphere and due to the production of excited states in the O þ O 2 þ M ! O 3 ðvÞ þ M recombination reaction. The energy flow into the ozone molecule as well as the collisional relaxation are highly uncertain. Model calculations that assume ozone formation at energies larger than 5000 cm À1 underestimate the measured radiances by a factor of 2-3 in the 50-75 km altitude regime, if the nominal relaxation scheme is assumed. Agreement between measured and modeled radiances is achieved, if the collisional rates for the transformation of hot band stretching to bending quanta are reduced by about a factor of three, or if the quasi-nascent distribution of ozone favors vibrational states in the 3000 cm À1 region. r
Geophysical Research Letters, 2007
Geophysical Research Letters, 2010
We used temperature data from the Michelson Interferometer for Passive Atmospheric Sounding on bo... more We used temperature data from the Michelson Interferometer for Passive Atmospheric Sounding on board ESA's Envisat satellite to analyze the temperature responses in the mesosphere and thermosphere up to 170 km to a major stratospheric sudden warming (SSW) which occurred in January 2009. The temperature observations show clear signatures of a mesospheric cooling and a thermospheric warming, the latter peaking at 120-140 km in agreement with model predictions. From the analysis of the zonal temperature structure during the SSW a pronounced wave 1 pattern was found in the entire middle and upper polar atmosphere with maximum amplitudes around 50 and 140 km. In the mesosphere, the wave amplitude is significantly damped. The wave amplification above is most likely produced by in situ forced planetary waves in the mesosphere and lower thermosphere region. Our observations represent the first experimental evidence of a dynamical coupling of the lower atmosphere and the thermosphere in the 120-150 km range by means of satellite data.
Journal of Geophysical Research, 2005
1] Time series of stratospheric ClO and HOCl have been measured with the Michelson Interferometer... more 1] Time series of stratospheric ClO and HOCl have been measured with the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on board the Environmental Satellite (ENVISAT) during the solar storm episode in October/November 2003. A remarkable enhancement of ClO mean values (averaged over latitudes poleward from 70°N
Atmospheric Chemistry and Physics, 2011
We have compared composition changes of NO, NO as observed by the Michelson Interferometer for Pa... more We have compared composition changes of NO, NO as observed by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on Envisat in the aftermath of the "Halloween" solar proton event (SPE) in late October 2003 at 25-0.01 hPa in the Northern Hemisphere (40-90 • N) and simulations performed by the following atmospheric models: the Bremen 2-D model (B2dM) and Bremen 3-D Chemical Transport Model (B3dCTM), the Central Aerological Observatory (CAO) model, Fin-ROSE, the Hamburg Model of the Neutral and Ionized Atmosphere (HAMMONIA), the Karlsruhe Simulation Model of the Middle Atmosphere (KASIMA), the ECHAM5/MESSy Atmospheric Chemistry (EMAC) model, the modeling tool for SOlar Climate Ozone Links studies (SOCOL and SO-COLi), and the Whole Atmosphere Community Climate Model (WACCM4). The large number of participating models allowed for an evaluation of the overall ability of atmo-Correspondence to: B. Funke ([email protected])
Atmospheric Chemistry and Physics, 2010
Except for a few reactions involving electronically excited molecular or atomic oxygen or nitroge... more Except for a few reactions involving electronically excited molecular or atomic oxygen or nitrogen, atmospheric chemistry modelling usually assumes that the temperature dependence of reaction rates is characterized by Arrhenius law involving kinetic temperatures. It is known, however, that in the upper atmosphere the vibrational tempera-5 tures may exceed the kinetic temperatures by several hundreds of Kelvins. This excess energy has an impact on the reaction rates. We have used upper atmospheric OH populations and reaction rate coefficients for OH(v = 0...9)+O 3 and OH(v = 0...9)+O to estimate the effective (i.e. population weighted) reaction rates for various atmospheric conditions. We have found that the effective rate coefficient for OH(v = 0...9)+O 3 can 10 be larger by a factor of up to 1020 than that involving OH in its vibrational ground state only. At altitudes where vibrationally excited states of OH are highly populated, the OH reaction is a minor sink of O x and O 3 compared to other reactions involving, e.g., atomic oxygen. Thus the impact of vibrationally excited OH on the ozone or O x sink remains small. Among quiescent atmospheres under investigation, the largest while 15 still small (less than 0.1%) effect was found for the polar winter upper stratosphere and mesosphere. The contribution of the reaction of vibrationally excited OH with ozone to the OH sink is largest in the upper polar winter stratosphere (up to 4%), while its effect on the HO 2 source is larger in the lower thermosphere (up to 1% for polar winter and 1.7% for midlatitude night conditions). For OH(v = 0...9)+O the rate coefficients 20 differ by plus/minus a few percent only from those involving OH in its vibrational ground state. The effects on the odd oxygen sink are negative and can reach −0.7% (polar summer lowermost thermosphere), i.e. neglect of vibrational excitation overestimates the odd oxygen sink. The OH sink is overestimated by up to 2%. After a solar proton event, when upper atmospheric OH can be enhanced by an order of magnitude, the 25 excess relative odd oxygen sink by OH(v = 0...9)+O 3 is estimated at up to 0.2%, and the excess relative OH sink by OH(v = 0...9)+O 3 can exceed 4% in the thermosphere.
Advances in Space Research, 2005
Ozone volume mixing ratio (VMR) profiles are measured by the Michelson Interferometer for passive... more Ozone volume mixing ratio (VMR) profiles are measured by the Michelson Interferometer for passive atmospheric sounding (MIPAS) on ENVISAT. The data sets produced by the science data processor at Institut fü r Meteorologie und Klimaforschung (IMK), Germany are compared with those obtained by halogen occultation experiment (HALOE) on UARS and by sub-millimetre radiometer (SMR) on ODIN. For the stratospheric measurements taken during September/October 2002, the three instruments show reasonable agreement, with global mean differences within 0.1-0.3 ppmv. The typical zonal mean differences are of 0.4 ppmv for HALOE and 0.6 ppmv for SMR (4-6%) in the ozone VMR peak region at 25-30 km near the equator, though larger differences of 0.8-1 ppmv (8-10%) are also observed in a small latitude-altitude region in the tropic. A positive bias of about 0.2-0.4 ppmv in the MIPAS data in the 35-40 km region has also been found. Further studies are under way to explain these differences.
Geophysical research …, Jan 1, 2001
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Papers by Manuel Lopez-Puertas