The database of MIPAS level-2 products
retrieved with the 2-dimensional GMTR algorithm
(MIPAS2D) is made available at MIPAS Bologna Facility to promote the
use of MIPAS products and stimulate scientific collaboration.
MIPAS2D result files can be
downloaded via scp from MBF.
The credentials can be obtained sending an e-mail to: bm.dinelli (at)
isac.cnr.it or to: massimo.carlotti (at) unibo.it.
The currently released MIPAS2D version 1.0
consists of the retrieval of observations of MIPAS main targets
(pressure, temperature, H2O, O3, HNO3, CH4, N2O and NO2) from the
entire Full Resolution (FR, July 2002 to March 2004) mission, and its
new configuration with the Optimized Resolution (OR, January 2005 to
date). Version 1.0 has been obtained analysing MIPAS level-1b data
produced with different versions of the ESA Instrument
Processing Facility (IPF): version 4.61 and 4.62 for the FR
mission, and version 4.65 (up to 14 July 2006), and version
4.67 (afterwards) for the OR mission.
Version 2.1 has been obtained analysing MIPAS level-1b data
produced with IPF version 5.02.
The database is continuously updated with new measurements.
are calculated in the range 6 to 68 km over a common fixed vertical grid, at
steps of 3 km up to 42 km and at the altitudes of 47, 52, 60 and 68 km
(MIPAS original nominal altitudes). A thorough desciption of
the database can be found in the AMT
"The MIPAS2D database of
retrieved with a multi-target 2-dimensional tomographic approach"
The MIPAS2D database is available
with two different horizontal-grid definitions:
- NOMINAL GRID (NOM)
- Each vertical profile is aligned at the average latitude of the
tangent points of MIPAS individual limb-scans. The horizontal retrieval
grid nodes are thus placed where the maximum information is expected,
although MIPAS observations are performed at variable latitude intervals.
- FIXED GRID (GRD) - The
horizontal retrieval grid is fixed for all the analyzed orbits:
vertical profiles are aligned at latitudes equispaced by 5° over
the whole latitude range -90° to 90°. At negligible costs of
precision of the retrieval, this dataset is useful to minimize the need
of interpolation for the end user (averaging processes or
intercomparison with other observational/model datasets).
The MIPAS2D database is available for
the following observation modes:
- The NOMINAL observation mode (that is different for the FR and OR measurements)
- The UTLS-1 observation mode (for OR measurements only)
- The Middle Atmosphere observation mode (for OR measurements only)
The list of level-1b files processed for
the production of the database can be found here, where
the tag on the right column indicated the MIPAS observation mode (for
example NOM-FR means: nominal mode, full resolution).
The geophysical parameters pressure,
temperature, H2O and O3 were determined simultaneously with a
Multi-Target Retrieval (MTR); the other targets were determined in
cascade on retrievals following the MTR, each new step exploiting the
atmospheric fields previously determined.
All datasets are obtained using
optimal estimation without regularization, and high cloud index
filtering. Geolocation information, random errors and chi-squares of
the retrievals are stored together with the
individual information gain (that represents the gain of information
obtained in the retrieval when compared to the
details on the database
The data are stored into directories
whose name is of the general form TYPE_OBSMOD_RETGRID_VERSION.
Currently, TYPE "FR" corresponds to the Full
Resolution mission and "OR" corresponds to the Optimised Resolution mission,
OBSMOD is the label for the analysed observation mode,
RETGRID is the label of the corresponding horizontal
retrieval grid and VERSION is a progressive number
that labels the improved version of the database.
GMTR level-2 products reported in the
database have passed a basic quality check and a filtering process
based on the chitest value of their fitting procedure (chi-square <
7.0, only on MTR retrieval). The filtered results are stored on the server
as compressed .tgz files, one for each orbit. In the FR dataset, out of
6794 analyzed level-1b files, 5725 have generated acceptable NOM result
files and 5798 GRD files. Given that the full advantage of the
2-dimensional retrieval is due to exploiting the information of
adjacent limb-scans, orbit chunks having less than 20 minutes of
observations were rejected (a full orbit is about 100 minutes). Because
of the use of the optimal estimation, results should be always used
together with their individual information gain (a value of 0 implies that the
final results are based only on the apriori information). Negative
values of the individual information gain are used to flag data to be rejected.
Other further details can be made available on request.
Remark: GMTR operates simultaneously
on measurements acquired during a complete orbit. The analysed orbit originates and
closes at the North Pole where the geographical distance between the
air masses observed by the first and the last limb-scans is minimum.
Since the first limb-scan of the level-1b files occurs far from North
Pole, level-1b files of two consecutive orbits are joined by GMTR to
produce a full orbit of measurements to be processed.
File names YYYYMMDD_OUT_GMTR_NUM1+NUM2.tgz
- the year YYYY, month MM
and day DD of the first orbit,
- the number of the two consecutive orbits used in the
retrieval NUM1 + NUM2. If the level-1b of the
subsequent orbit does not exist, the retrieval is performed only on the
first orbit and _singl is used in place of +NUM2.
Untarring the .tgz file with the command (tar -zxvf
YYYYMMDD_OUT_GMTR_NUM1+NUM2.tgz) creates a directory OUT_GMTR_NUM1+NUM2
- X_results.dat: file
of the results for target X reporting latitude (LAT), longitude (LONG),
Orbital Coordinate (O.C.), altitude (ALT), the target quantity (P, T or
VMR), the Estimated Standard Deviation (ESD), date and time (Time) and
the information content (Inf). For convenience of the user, in the VMR
result files pressure and temperature values are also reported in
additional columns after the "Time" column. The fortran routine used to
write these files can be found in write_results.f,
chitest evolution at each iteration in the retrieval procedure.
In order to handle MIPAS2D datasets,
additional programs are provided in the directory TOOLS. Inside, the
README file reports the instructions to complile and use this
Currently, the following programs are
- extact_data: the
program is interactive and is given just as an example on how to
extract data from the database. It enables to extract data from the
database on a given latitude, longitude and time box.
the program is interactive and enables to extract data for all
observation modes on the GRD horizontal retrieval grid
errors and ESDs
Systematic errors (in %) for a global
average atmosphere (glw) can
be found in: PTHO_000.err_1cm for
pressure, temperature, H2O and O3, ch4_000.err,
hno3_000.err, no2_000.err, n2o_000.err
for the other target quantities. In these files, the total systematic
error and the single components that contribute to this error are
reported for each retrieval altitude. Pressure, temperature, H2O and O3
errors have been computed for the 2D Multi Target Retrieval System.
CH4, HNO3, NO2 and N2O errors were generated for a 1D retrieval system,
so they include the systematic error due to the assumption of
horizontal homogeneity of the atmosphere (GRA) that should be
disregarded in this 2D retrieval. The total error for each altitude is
the quadratic summation of the ESD (reported in the X_results.dat
files) and the systematic error components. For a detailed explanation
of the error-file formats use the link MWMAKE where
the Error Analysis File is described.
The list of microwindows used for the retrieval of each target in
the FR and OR measurements can be foud here . An estimate of the total systematic error is also reported.
Plots showing average and median values along with the Estimated Standard Deviations (ESDs) computed for four different periods of years 2005-2010 (only 2008 for ESDs) are also available.
JFM=January, February, March; AMJ=April, May, June; JAS=July, August, September; OND=October, November, December; DJF=December, January, February; MAM=March, April, May; JJA=June, July, August; SON=September, October, November
NP= North Pole; MIDN=Mid latitude North; EQUN=Equatorial North; EQUS=Equatorial South; MIDS=Mid latitude South; SP=South Pole
In addition to the MIPAS2D data, a separate
directory AK is used to store examples of the 2-Dimensional
Averaging Kernels of MIPAS2D database. Due to the size of the AK files
the AK of the individual retrievals are not stored into the database.
However they can be made available to the users upon request.
The AK directory contains examples of the Averaging Kernels
for the GRD products of MIPAS2D database and a program to compute
the vertical and horizontal resolution from any AK matrix produced
by the GMTR analysis system.
The program for reading the AK files and compute the vertical
and horizontal resolution is stored in the directory PROG.
The averaging kernels files are organized into 4 directories:
FR_NOM_GRD: contains the data
for the FR mission on the GRD retrieval grid for the nominal observation mode
OR_NOM_GRD: contains the data
for the OR mission on the GRD retrieval grid for the nominal observation mode
OR_UTL_GRD: contains the data
for the OR mission on the GRD retrieval grid for the UTLS-1 observation mode
OR_MAT_GRD: contains the data
for the OR mission on the GRD retrieval grid for the Middle Atmosphere
Each of these directories contains the folders:
January: for the data obtained using climatological data for January (i.e.
North Emisphere winter data)
April: for the data obtained using climatological data for April (i.e. North
Emisphere spring data)
July: for the data obtained using climatological data for July (i.e. North
Emisphere summer data)
October: for the data obtained using climatological data for October (i.e.
North Emisphere fall data)
Each of this folders contains 2 subdirectories:
AvKer: contains the Averaging Kernel data (one file for each target)
RESOLUTION: contains the data on the vertical and horizontal
resolution of the MIPAS 2D products
Additional files (i.e. columns, spectra etc.)
can be made available upon request
distribution policy: the database is released for
academic and non profit purposes. Invitation to co-authorship on
scientific papers should be considered.