1. MIPAS-2D water database and its validation
B.M. Dinelli
ISAC-CNR – Bologna – Italy
With the help of
E. Arnone, E. Castelli - ISAC
M.Carlotti, L. Magnani, E. Papandrea DCFI – University of Bologna - Italy
M. Prevedelli, M. Ridolfi DF- University of Bologna – Italy
A. Burini, S.Casadio SERCO - Italy

2. MIPAS/ENVISAT
MIPAS measurements have been mainly acquired using two different spectral and geographical resolutions:
Full Resolution mission (FR)
From June to March 2004
Spectral resolution cm-1
~72 scans per orbit on 17 views ranging from 6 to 68 km
Optimized Resolution mission (OR)
From January 2005 to April 2012
Spectral resolution
~92 scans per orbit on 27 limb views ranging from 3 to 70 km
MIPAS measurements are directly processed by ESA in two stages
Interferograms are converted in calibrated and geolocated spectra (level1b data)
Spectra are analysed to obtain vertical distributions of p,T and VMRs of several key species: H2O, O3, HNO3, CH4, N2O, NO2, etc. (level 2 data)
ESA level 2 data are obtained with the ORM algorithm (retrieval on tangent points, horizontal atmospheric gradients neglected)

3. FR OR ∆Lat = ~4.6o ∆Lat = ~3.7o Constant altitudes along the orbits
Variable altitudes along the orbit
~72 scans
~94 scans
17 altitudes
27 altitudes
0.025 cm-1
cm-1
∆Lat = ~4.6o
∆Lat = ~3.7o OR FR

4. GMTR retrieval system
The GMTR code (Carlotti et al., Appl. Opt., 45, , 2006) has been developed to analyse MIPAS observations
The main characteristics of GMTR are:
The horizontal inhomogeneities of the atmosphere are properly modelled using a 2-D discretization of the atmosphere.
Observations of a full orbit can be simultaneously analyzed
The (2-D) retrieval grid is fully independent from the measurement grid.
Target species can be retrieved simultaneously (Multi-Target-Retrieval) in order to suppress the systematic error due to spectral interferences.

5. GMTR retrieval system
The 2-D FM internal to the GMTR code can be used to study the effects of horizontal gradient in 1-D analysis
The data retrieved with GMTR are not affected by the error due to neglecting temperature horizontal gradients (Kiefer et al., AMT, , 2010)

6. MIPAS2D database
The GMTR code has been applied to the full MIPAS mission and the MIPAS2D database has been developed (Dinelli at al., AMT,3, , 2010)
Retrievals have been performed using Optimal Estimation
Cloudy spectra have been removed from the analysis
The database is public and can be downloaded following the instructions given in the web sites:
The database containes 2-D fields of: p, T, H2O, O3, HNO3, CH4, N2O, NO2 for the full mission
CFC-11, CFC-12, N2O5, COF2, ClONO2 (minor species) are also present
Because of their correlations P,T, H2O, O3 have been jointly retrieved
The other targets are retrieved singularly in cascade.
2-D Averaging Kernels available upon request

7. MIPAS2D database
The data have been retrieved on a fixed vertical grid (17 altitudes)
From 6 to 42 km at 3 km steps + 47, 52, 60, 68
Two types of horizontal grids for both the FR and OR mission
GRD - fixed at 5 degrees latitudinal steps
NOM – at the average latitude of each MIPAS scan
The GRD retrieval grid makes the spatial resolution of both FR and OR products homogeneous
Level 1b data processed with IPF V5.X
Originally the analysis was performed with two different sets of MWs (target dependent) one for the FR mission and one for the OR mission
FR mission has been analysed also with the OR MWs
For this analysis the spectral resolution of MIPAS spectra has been artificially degraded to the OR
Most MIPAS observation modes analysed (NOM - UTLS - MA)

8. H2O time-series 15N-15S

9. Time series of month-pressure distributions of water vapor anomalies in the vertical range 50 to 5 hPa (15N-15S)

10. Zonal mean of water distribution from 2002 to 2010

11. Validation We have started to validate the version 2 of MIPAS2D
We are currently using data from other satellite instruments (MLS, ACE)
Coincidence criteria:
Time mismatch 60 min
Distance < 500 km

12. Water MIPAS2D vs ACE South Pole

13. MIPAS2D vs MLS South Pole

14. North Polar region

15. Mid-Lat North

16. South Polar region

17. Comparison with ACE and MLS January
South Pole
Mid-Lat South
Mid-Lat North
North Pole

18. Comparison of Temperature with MLS and ACE
South Pole
Mid-Lat South
Mid-Lat North
North Pole

19. Conclusions
We have analysed all the measurements in the observation modes NOM UTLS and MA of MIPAS for the whole mission (July 2002 to April 2012).
The 2D fields of pressure, temperature and VMR of H2O, O3 have been obtained on a fixed altitude grid at two horizontal grids: fixed at 5 deg steps or at the scan geolocation, for the whole mission.
The analysis has been performed with the GMTR system that enables the tomographic retrieval of MIPAS data taking properly into account the horizontal inhomogeneities of the atmosphere.
The resulting database is available to end users and can be dowloaded following the instructions contained into the web sites: and
The database includes results for the FR mission analysed with the same set of MWs of the OR
2-D Averaging Kernels can be distributed upon request

20. Conclusions
Validation with satellite data (ACE and MLS) shows a positive bias of about 5% from 200 to 1 hPa wrt both instruments
Above and below higher differences are present
Consistent behavior in all latitude bands
Comparison of the temperature profiles (retrieved simultaneously) with ACE and MLS doesn’t show the same behavior therefore no correlations
We are currently working to reduce the differences by changing the set of analysed MWs