Carmela Cornacchia: LIDAR AND RADIOSONDE MEASUREMENT CAMPAIGN IN POTENZA
FOR THE VALIDATION OF ENVISAT ATMOSPHERIC PRODUCTS
An intensive aerosol and water vapour lidar measurement campaign, started on
July 2002, is in progress at IMAA-CNR in Tito Scalo (PZ) (Southern Italy,
40°N, 15°E, 820 m above sea level) in the frame of the validation program
of ENVISAT. A Raman lidar system is used to perform both aerosol and water
vapour measurements; aerosol backscatter and extinction coefficients are
retrieved from simultaneous elastic signals at 355 nm and inelastic N2 Raman
backscatter lidar signals at 386.6 nm, whereas, water vapour mixing ratio
measurements are retrieved from simultaneous H2O and N2 Raman signals.
Systematic measurements will be performed for a period of 12 months. Two
measurements per week are scheduled for the first six months of the validation
campaign, while one measurement per week is scheduled for the last six months.
All the lidar observations are complemented with radiosonde launches. First
results of the intercomparison between water vapour lidar profiles and MIPAS
profiles will be presented. Comparisons of radiosonde measurements of pressure
and temperature with MIPAS and GOMOS profiles will be presented.
Sagnik Dey: Aerosol optical properties in the coastal and northern India
Poster gives an overview of the aerosol optical properties in the coastal and
northern India (Gangetic basin), which despite of being one of the highly
polluted regions, remain unexplored over years. The aerosol seasonal variability
in these regions will be discussed.
Gaelle Dufour: COMPARISON BETWEEN LPMA MEASUREMENTS AND 3D REPROBUS MODELLING USING A BOX MODEL : SENSITIVIIY OF VERTICAL PROFILES TO TIME, LATITUDE, LONGITUDE AND IMPLICATIONS ON NOy MODELLING
Mixing ratio profiles of ozone and several NOy species were measured using the Limb Profile Monitor of the Atmosphere (LPMA)
instrument during ascent, occultation and sunset for a balloon flight, which took place on August 21, 2001 from Kiruna (Sweden). These profiles were compared with the Reprobus 3D chemistry transport model (CTM) results for a latitude and a longitude area close to the mean balloon position. Discrepancies between model and measurements are observed particularly for the photochemical variation of NO2 and NO between ascent and sunset. A more precise comparison, taking into account the variation with time of the position (latitude, longitude) of the probed air mass reduces the disagreement between model and measurements. The box model Reprobus 1D has then been used to study in detail the photochemical variation of NO2 and NO. A robust interpolation scheme was used to initialize the box model with LPMA. Reprobus 1D reproduced well the photochemical variation of NO2 and NO measured by LPMA observations. The intercomparison procedure and the corresponding results will be presented.
Sven Gabriel: Sequential assimilation of a long lived tracer in a 3-D CTM
A data assimilation routine has been implemented in the 3D-chemical transport model (CTM) KASIMA (KArlsruhe Simulation model of the Middle Atmosphere) Here the sequential technique of Khattatov et al. (J. Geophys. Res., 105, 29,135-29, 144, 2000) is applied to the long lived tracer CH4 from Halogen Occultation Experiment (HALOE). Results of an one year (1994) assimilation model run are compared with KASIMA calculations without assimilation and CRISTA and ATMOS measurements.
Andreas Gobiet: The CHAMPCLIM Project: Building Radio Occultation Based Climatologies
The global coverage, all-weather capability, high accuracy, and self-calibrated nature of radio occultation (RO) data suggests them as a near-ideal resource to build global climatologies of fundamental atmospheric variables such as temperature and humidity. The CHAMP (Challenging Minisatellite Payload) RO data provides the very first opportunity to create RO based climatologies. We aim at using the complete CHAMP RO data flow for month-to-month, season-to-season, and year-to-year global climate monitoring via temperature, geopotential height, and humidity fields. Here we show preliminary results based on simulated and measured data.
Beate Hildenbrand: Global Ozone Analyses by Assimilating SCIAMACHY and GOME Observations into a 3D CTM
The poster is describing our current work at DLR-DFD regarding data assimilation into a 3D CTM. Vertically resolved ozone profiles are derived by assimilating satellite based ozone total column measurements into the 3D-NCAR-ROSE (NCAR Research on Ozone in the Stratosphere and its Evolution) chemical-transport model.
Adam Jaczewski: The radiosounding network in Poland and some research results
The radiosoundings in Poland are performed from 1948 and ozonesoundings from 1979. Long-term variations in the vertical temperature structure of the atmosphere play an important role in the detection of climate change. Estimations of the temperature trends indicate accelerated warming of the boundary layer and free troposphere since 1979, exceeding 2K/decade for winter months. In the upper troposphere, the temperature trends reverse. At the tropopause negative trends for 1961-2002 can be observed throughout the year. The acceleration of the cooling of the stratosphere has been stated since 1979. It can be attributed to large negative ozone trends observed on Legionowo soundings. The frequency of episodic intrusions of ozone depleted air masses from the cold Arctic polar vortex has increased over Poland since the early 1990s. The radiosoundings data can also be applied to validation of temperature, water vapour and ozone profiles from satellite sensors. Centre of Aerology is involved in project of validation of SCIAMACHY data.
Dagmar Klasen: Using horizontal field correlations for variational chemical data assimilation
We assimilated CRISTA trace gas measurements into the adjoint chemistry-transport model AMMOC-CTM. The smoothness of the observed horizontal trace gas fields motivated us to include a penalty term in the cost function that controls the curvature of the analysed mixing ratio field at a given pressure level. By this term the integration was stabilised. On this poster the method will be compared to the use of off-diagonal elements in the background error covariance matrix and the results obtained by application to CRISTA data will be presented.
Rebekah Martin: Interaction of Cyclones with Greenland's Orography
MM5 simulations of cylones over the open ocean in the vicinity of Greenland.
Jana Mendrok: A radiative transfer model for the wavelength region of 2500-4000 cm-1
By pointing out the characteristics of the named wavenumber region the requirements of a new model are worked out. The basic ideas for such a rt-model are presented as well as first results in implementing the solar single scattering to a LbL-based rt-code for TIR.
Lisa Neef: Balanced Dynamics and the Kalman Filter: Implications from a Simple Model
The ability of the Extended and Ensemble Kalman Filters to balanced atmospheric flow is examined, using a model that admits both slow, chaotic vortical modes and a comparatively high-frequency inertia-gravity wave, but contains only 4 variables and is therefore very useful for the testing and comparison of data assimilation algorithms. We find that, while four-dimensional assimilation algorithms like the Kalman Filter can very successfully track slow / quasigeostrophic motion by calculating dynamically-consistent error covariances, they do not necessarily reflect dynamical balance within the covariance model, and can thus easily return a state containing spurious gravity-wave modes.
Christian Retscher: AN ADVANCED ENVISAT/GOMOS TEMPERATURE AND OZONE RETRIEVAL: ALGORITHM AND FIRST RESULTS
We developed a realistic forward model for transmission measurements representing a key ingredient in our ozone retrieval algorithm. An optimal estimation technique was used to retrieve representative atmospheric profiles. Besides the objective to retrieve ozone profiles based on the data at nine selected channels between 260 nm and 334 nm and two channels at 602 nm and 634 nm, a simultaneous retrieval of bending angles, refractivity, and temperature from GOMOS star tracking data was performed.
The GOMOS Steering Front Assembly (SFA) and the Stellar Tracking Unit (SATU) provide information on bending angles via pointing data. According to the precision of the SFA and SATU pointing data at a sampling rate of 10 Hz (downgraded here from 100 Hz) we assumed bending angle errors of 3 murad. We retrieved refractivity, also used to improve bended-ray information within the ozone retrieval process, forming the basis of a subsequent calculation of temperature profiles. Statistical optimization of bending angles was then used to show a significant gain in temperature retrieval quality. We present preliminary results on simulated and real data sets, where errors of ozone tend to stay below 2% throughout the mid stratosphere and mesosphere region, while temperature was found with errors 1.5 K in the low stratosphere.
Kunhikrishnan Thengumthara: Synergetic use of MATCH-MPIC and GOME Satellite data for the study of Tropospheric NOx over Asia
AThis study examines the sources and distribution, losses and other properties of tropospheric NOx over south Asia especially India using the global 3D chemistry-meteorology model (MATCH) and the GOME NO2 column. A major objective is to demonstrate how satellite data can be combined with model results to improve our understanding of chemical and physical process in the atmosphere over Asia. The agreement between both the MATCH and GOME regional lifetimes and annual mean total NO2 columns implies that it is likely that the total NOx emissions amount used in the current MATCH simulation is about appropriate. The study also analyse the uncertainties in the estimation of the NOx emission strength from GOME.Implications of these results are discussed. the NOx emission strength from GOME.Implications of these results are discussed.