Archive by Author | peterjldempsey

CHARMe from a Hydrometeorologist’s POV

CHARMe from a Hydrometeorologist’s POV

CHARMe (CHARacterisation of Metadata) is an online system for collecting and sharing metadata and user feedback on climate and earth science datasets. It will help users of climate data judge how suitable the data are for their intended application and enable them to add commentary on specific benefits, features and limitations discovered when using the data.

The CHARMe project is now close to going live (, and a beta version is planned for December. Data providers signed up so far include ECMWF, CGI, BADC and KNMI. In addition to metadata provided at source, CHARMe will enable users to share rich commentary data and user experience using an annotation user interface. Users annotation will be stored on an independent CHARMe server, and updated centrally so that users can always see most up to data information.

CHARMe will benefit working scientists and researchers. As a hydro-meteorologist, I’m interested in precipitation data from models, and observations including rain gauges, weather radar, and satellites. Modelled rainfall has known data quality issues, especially the underestimation of high intensity events and extremes. CHARMe will enable users to highlight spatial and temporal anomalies, missing data, or other unusual trends, biases, or discontinuities. It would be valuable if issues were highlighted in CHARMe by previous researchers saving time and resources spent reassessing the data.

Remote sensed satellite data are a valuable source of data for earth scientists working in data scarce regions. These data often require a degree of specialist knowledge to interpret, including knowledge of observation systems, data and processing. Datasets may include anomalous data, for example TRMM satellite precipitation maxima, and CHARMe will allow specialists and users to add commentary on issues found when applying data, saving time for users and avoiding duplication of errors. It could also help data providers prioritise development effort.

Similarly rainfall observations from weather radar are routinely reprocessed to account for ground clutter, bright band and other phenomena which affect data quality. And rain-gauge and other synoptic data may suffer from instrument error, missing data, or communications issues. CHARMe is a useful tool for data providers to flag up changes in processing algorithms or significant data outages etc.

Good quality commentary will document actual user experience and provide an empirical indication of data quality to counter anecdotal information and hearsay of uncertain quality. Importantly, a qualitative indicator of data quality and model uncertainty will complement quantitative estimates of uncertainty provided with the model data.

In summary, CHARMe will benefit a range of existing and future data users in climate and environmental science by adding confidence in the source, provenance, and quality of model and observations datasets. It will provide metadata and commentary which will and add value to research programmes and encourage intelligent applications. A CHARMe user forum and blog at will enable users to share results and experience with a wider audience

CHARMe is being publicised at the 10th European Conference on Applied Climatology (ECAC), Prague 6-10th October, the Climate Symposium in Darmstadt, 13-17th October, the CCI Co-location meeting at ESRIN, Italy, 20-24th October, the ESA Big Data from Space conference, 12-14th November, and the AGU, San Francisco, 15-19th December.