Our main interest is in producing high-resolution climate fields over spatially extensive regions, primarily from historical (weather-station) records, to help us understand and document large-scale climate patterns and climatic change. Seasonal and interannual scales of temporal variability are of particular concern. Our gridded climate fields also have been used for initializing and verifying global climate models (GCMs), as well as for corroborating satellite-derived estimates of climate variables. In addition, we are working to improve our spatial interpolation algorithms, as well as statistical approaches to accuracy assessment. Many of the gridded climate fields that we have produced are available through this Web site.
As procedures for spatially interpolating (“gridding”) climate data improve—and previously unavailable station records become available—we reassess large-scale climate and climatic change as represented within the instrumental (weather-station) record. A number of average monthly and annual air-temperature (T) and precipitation (P) fields, for example, have been and are being reestimated on a 0.5×0.5 degree grid. Monthly and annual climatological averages of evapotranspiration (E), soil moisture (w) and other water-budget variables (forced with our gridded T and P fields) also have been estimated an a 0.5×0.5 grid.
Through collaboration with colleagues at the Institute of Global Environment and Society (IGES), at the University of New Hampshire and at other institutions (and with support from NASA), we work to reassess the large-scale hydroclimatology of tropical land surfaces. This research began in the mid-1990s. Our original focus was on South American P, but our purview now extends to the entire tropical land area. Producing more realistic rainfall fields from the historical record has been our main interest, although we also have evaluated T as well as the components of the soil-water budget.
In the past, with NSF and NASA support, we worked with colleagues—primarily at the University of New Hampshire and the Woods Hole Marine Biological Laboratory—to investigate the hydroclimatology of the “...Pan-Arctic Drainage System.” Working mainly from the historical weather-station record, we reestimated the spatial, seasonal and interannual variability in the high-latitude water cycle. Our emphasis was on P, although spatially high-resolution T fields were produced as well.
In support of our efforts to produce better gridded climate fields from the historical weather-station record, we continue to develop and refine methods for the spatial interpolation of climate data from sampled to unsampled points (usually on a grid). Moreover, to help us assess the accuracy of our estimated (gridded) climate fields, we have been and are refining spatial cross-validation and model-performance methods, many of which are described and used in our publications.