The new satellite instrument, IASI (Infrared Atmospheric Sounding Interferometer), is a moderate resolution (0.25 cm-1) Fourier Transform spectrometer launched in 2002 on the European METOP satellite. This instrument offers more spectral channels at a considerably higher spectral resolution than HIRS (High Resolution Infrared Sounder) - the instrument which it replaced as the operational infra-red sounder. IASI delivers vertical profiles of temperature and humidity data with a resolution of 1km compared with approximately 4km from HIRS. Translating the improvement in the spectral resolution of the instrument into improvements in the accuracy and height resolution of the temperature, humidity and ozone profiles is dependent on a detailed knowledge of the spectroscopy of the atmosphere in this spectral region. The aim of the Validation of IASI (Infrared Atmospheric Sounding Interferometer) Radiative Transfer Experiments and Modelling (VIRTEM) project was to make the improvements to the spectroscopy necessary to make full use of the increased spectral resolution of IASI. The primary objectives of the VIRTEM project were: *To generate a detailed set of atmospheric observations of radiances and supporting in-situ data. *To analyse and validate the current spectroscopy using state of the art line-by-line radiation models. *To generate an improved spectroscopic database. VIRTEM was an EU project to validate the instrumentation and retrieval methods to be used on IASI. Data in this dataset collection include both aircraft based and lab based spectroscopic measurements.

The data on this 2 CD set was derived from the the first Along-Track Scanning Radiometer (ATSR-1) which was a four-channel, dual-view, infra-red radiometer capable of measuring Sea Surface Temperature to very high accuracy (better the 0.3K). The instrument was launched on the ESA remote sensing satellite (ERS-1) in July 1991. The dataset consists of two types of data product: (a) Spatially averaged sea surface temperatures (ASSTs) and (b) Time averaged global maps. The ASSTs are provided daily in half-degree cells together with with temporal and positional confidence information. The time-averaged global maps are provided at half degree resolution averaged over 5 day and 1 month periods. The data on the CDs cover the four year period from August 1991 to July 1995 inclusive. The Principal Investigator for ATSR-1 is Chris Mutlow at the STFC Rutherford Appleton Laboratory (RAL).

Frontal zones are regions where are descending from the upper troposphere and lower stratosphere comes in close proximity to rising air of recent boundary-layer origin. Such zones are often strongly sheared and subject to shearing instability and mixing. The aim of the UTLS-DCFZ project was to investigate the nature and effect of the mixing of the two airmasses which may be characterised by very different chemical compositions. In particular, the experimental campaign helped answer questions concerning: The distribution of chemical species around fronts. The role of frontal systems in transporting chemical species from the boundary layer and the stratosphere into the troposphere. The extent and rate of mixing between the differing air-masses in the vicinity of fronts. The effect of this mixing on the photochemistry of OH and ozone. The effect of this mixing on the dynamical structure of the front, which will feed back through 1. and 2. above. Five flights were carried out between January and April 1999, two of which were in the period which overlapped with MAXOX. These flights sampled a range of frontal situations, so the main improvement which could be made to the dataset would be to sample more fronts in a similar way, to improve the statistical basis for any analysis. Aircraft measurements of the chemical (e.g. CO, O3, NOx as well as MAXOX measureables during some of the flights), thermodynamic, physical (e.g. liquid water content, CCN etc.) and dynamical characteristics of a number of frontal situations were made. Chilbolton radar images are also available.

The UGAMP ozone climatology consists in a 4-dimensional distribution of ozone that has been built up from the combination of several observational data sets. These data sets include satellite observations (SBUV, SAGE II, SME, TOMS) as well as ozone sonde data provided by the Atmospheric Environment Service of Canada. This global climatology, covering five years (1985 to 1989), was originally established to replace the simpler ozone climatologies used as input in the UGAMP models (ECMWF parameterization or 2-D zonal means deduced from satellite data). It provides monthly means of the ozone column above the grid levels as well as 5-year averages and zonal averages of these monthly means, on a 2.5 x 2.5 deg horizontal grid and over 47 levels, from the ground up to 0.001 mb. Software to convert ozone columns into mixing ratio and to interpolate the data on any required grid is also available.

To address the needs of the cryospheric science community, the SMMR-SSM/I, AVHRR and TOVS research teams collaborated to make it as easy as possible for the Polar Pathfinders and related data sets to be used together. The teams employed a common projection, the NSIDC Equal-Area Scalable Earth-Grid (EASE-Grid), file naming conventions and validation methods to develop consistently processed data sets that are easy to combine and contrast. The Polar Pathfinder Sampler CD-ROM is an innovative assemblage of atmospheric and surface measurements from all three Pathfinders. Included is a two-year period of daily merged Pathfinder data sets at 100 km-resolution, placed in a multidimensional structure known as the "P-Cube." In addition, samples of full-resolution Special Sensor Microwave Imager(SSM/I), TIROS Operational Vertical Sounder (TOVS) and Advanced Very High Resolution Radiometer (AVHRR) (both the 1.25 km and 5 km products) Polar Pathfinder data sets are included, also in Equal-Area Scalable Earth-Grid (EASE-Grid), making it easy to compare parameters at multiple resolutions. The new product provides data for a wide range of polar climate research applications, but is especially keyed to the needs of investigators dealing with large-scale atmospheric changes, surface heat and mass balance studies, and sea ice modelling. This dataset is public