The Mars Analysis Correction Data Assimilation (MACDA) dataset version 1.0 contains the reanalysis of fundamental atmospheric and surface variables for the planet Mars covering a period of about three Martian years (a Martian year is about 1.88 terrestrial years). This has been produced by data assimilation of observations from NASA's Mars Global Surveyor (MGS) spacecraft during its science mapping phase (February 1999–August 2004). In particular, we have used retrieved thermal profiles and total dust optical depths from the Thermal Emission Spectrometer (TES) on board MGS. Data have been assimilated into a Mars global climate model (MGCM) using the Analysis Correction scheme developed at the UK Meteorological Office. The MGCM used is the UK spectral version of the Laboratoire de Météorologie Dynamique (LMD, Paris, France) MGCM. MACDA is a joint project of the University of Oxford and The Open University in the UK.

This short paper outlines the key components of the NERC DataGrid: a discovery service, a vocabulary service and a software stack deployed both centrally to provide a data discovery portal, and at data providers to provide local portals and data and metadata services.

Abstract.The Climate Science Modelling Language (CSML) has been developed by the NERC DataGrid (NDG) project as a standards-based data model and XML markup for describing and constructing climate science datasets. It uses conceptual models from emerging standards in GIS to define a number of feature types, and adopts schemas of the Geography Markup Language (GML) where possible for encoding.A prototype deployment of CSML is being trialled across the curated archives of the British Atmospheric and Oceanographic Data Centres. These data include a wide range of data types -both observational and model -and heterogeneous file-based storage systems.CSML provides a semantic abstraction layer for data files, and is exposed through higher level data delivery services. In NDG these will include file instantiation services (for formats of choice) and the web services of the Open Geospatial Consortium (OGC).

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should be taken, however, in regions where large variations in flux or temperature are expected to occur.The present results may be extended by observing that the term "local" may be interpreted in the sense of a specific nodal surface rather than a point on a nodal surface, while "mean" refers to a collection or set of nodal surfaces. When this interpretation is made, it is possible to combine several nodal surfaces into subsets and formulate mean reflectances for the subsets, mean exchange factors among subsets, and mean-to-local exchange factors between nodes and subsets. In this way, a full set of N surfaces may be reduced to a smaller number of subsets, M < N. The advantage of this reduction lies in decreasing the size of the matrix implicit in Eqs. (20) and (22) and the economy of inverting the matrix to obtain Eqs. (21) and (23), respectively. Preliminary results indicate that this approach yields a sizable saving in computer time with accuracies suitable for most design applications. The analytical details and evaluation of this alternate interpretation will be the subject of a future communication.A qualitative evaluation of candidate thermal protection systems for a Mars-entry vehicle indicates that low-density charring ablators are most likely to meet all the requirements. Consequently, two such materials, foamed silicone and epoxy silicone low-density elastomers, were developed and characterized for this application. These materials, in addition to possessing good chemical resistance, are shown to have low thermal conductivities, high decomposition temperatures, and excellent low-temperature properties.