What the atlas is?

We may define this Atlas as "a set of digital climate maps of mean air temperatures (minimum, mean and maximum), precipitation and solar radiation". With these maps it is possible to know, every 180 m over the whole of the territory of Catalonia, what is the average maximum temperature, or precipitation or whichever of the other above-mentioned variables in terms of climate: that is, the average value based on all previous years for which data are available. Furthermore, these values can be consulted for the whole year (average values for temperature and solar radiation or accumulated values for precipitation), or for any specific month or for particular periods of interest (the seasons of the year).

These maps have been generalised using statistical techniques (multiple regression with residual correction), Geographic Information Systems (GIS) and spatial interpolation between the data from the meteorological stations.

Based on these maps it is possible to obtain new maps such as thermal ranges or evapotranspiration, again on a monthly or annual basis, etc. Since for all the variables we have, at least, monthly and annual data we have 13 maps for each variable (temperatures, etc) and, in total, more than 70 different maps, including those showing derived variables (thermal range, seasonal maps).

Why the atlas has been done?

To understand the aims of producing the Atles Climàtic Digital de Catalunya (Catalonia Digital Climate Atlas) two basic ideas should be borne in mind: on the one hand the interest that climatology has for many Earth Sciences (hydrology, ecology, biogeography) and applied disciplines (agroclimatology, forest management, land management, etc) and, on the other hand, the possibilities offered by technological (computers) and scientific (GIS) advances during the past decade.

Where the atlas has been done?

As an iniciative, originally of the Unitat de Botànica and the Departament de Geografia of the UAB (Barcelona), a research task was developed in order to deepen our understanding of aspects related to the spatial interpolation of data with a discrete spatial distribution (meteorological stations), originally orientated towards relating climate data and vegetation data, but later also focussing more intensely on climate issues. For more detailed information on scientific and technical questions related to the production of this Atlas consult the section of The Model on this same web page or the bibliography.

Who has done the atlas?

This research task has been carried out and led by Dr. Miquel Ninyerola (Unitat Botànica UAB), Dr. Xavier Pons (Departament de Geografia UAB) and Dr. Joan M. Roure (Unitat Botànica UAB).

Thanks to the interest in digital map databases shown by the Environment Department of the Catalonian Regional Government (Generalitat) and especially the Servei de Meteorologia de Catalunya (Catalan Meteorological Service), it has been possible to disseminate the maps derived from the models developed during this research. The dissemination of these climate maps has been carried out through two distinct media:

1) A CD-ROM together with some notes (Quaderns de Medi Ambient) published by the Environment Department of the Generalitat. This CD contains the digital version of the Catalonia Climate Atlas (l'Atles Climàtic de Catalunya - based on traditional isoline tracing techniques but produced by experts with knowledge of the climate of the country), our Digital Climate Atlas of Catalonia (based on objective numerical techniques and with a quantified level of error but without the corrections that a climatological expert might make) and a comparison of the two methodologies. The principal advantage of this CD+publication, apart from providing a tangible paper version, is that it gives a complete version of the Atlas, thanks to using a medium that holds 650 Mbytes of data, without having to download two versions of each and every map from the Internet, making it an ideal product for the general public, schools, etc.

2) This web page, where you can find the maps. The principal advantage of this page is that it aims to present the most up-to-date maps, generated with increasingly long data series and, as such, it should be a reference product for research, management and planning professionals who need the latest versions of the Atlas.

In both cases the maps are available in MMZ format. This is the format of the MiraMon Map Reader, a software application that allows visualisation, query, superposition, printing etc, of the maps in a true GIS, not just a simple bitmap or as visualised by more limited systems that do not allow detailed exploration of the data. This application has been developed at CREAF by the team led by Dr. Xavier Pons having been started by an initiative of the Departament de Medi Ambient de la Generalitat de Catalunya. This web site was awarded a Special Mention in the International Moebius Prize for the best application of Science and Technology in Internet in the year 2000. For more information on the technology used by the MiraMon Map Reader and to download a copy (required for consulting the maps) connect to: http://www.creaf.uab.es/miramon/mmr/index.htm.

How the atlas has been done?

To generate these maps air temperature and precipitation data were processed from 160 meteorological stations (one station per 200 km²) and 257 precipitation stations (one each 125 km²) respectively. These stations were selected according to a compromise between the length of the series (temporal stability) and density (spatial coverage). In the end, and after statistical checking, we have worked with 15 year time series for the temperature maps and 20 year series for the precipitation. For the solar radiation we have used 46 stations and 4 years of data.

This information has been processed in a GIS (MiraMon) which, together with a statistical package (Statistica), has allowed us to generate, validate and automate the map production process.

Where the atlas is going to?

The remaining objectives are to improve the quality of existing maps, as well as generating new maps (evapotranspiration for example).

In order to improve the maps two complementary strategies may be adopted:

1) Improve the quality of the input data. This can be done essentially by increasing the length of the time series of the stations (repeating the calculations with more years of data) and also by increasing the number of meteorological stations, something that depends on the public authorities.

2) Improve the model (for example by testing different spatial interpolation techniques)