Integrated Information Resources for Drought Assessment on All Time Scales
When assessing and addressing issues related to drought, it is critical to have a diverse assemblage of information that bridges multiple temporal and spatial scales. Of greatest immediacy for decision makers is an evaluation of recent and current conditions on time scales ranging from daily to seasonal or even interannual. In addition to specific, drought-related indexes such as the U.S. Drought Monitor and U.S. Forest Service Fire Danger Rating, other variables of interest may include precipitation, snow pack water content, surface air temperature, humidity, evapotranspiration, soil moisture, stream flow, groundwater levels, reservoir levels, and foliage or range conditions. Because absolute values and anomalies of all variables are important, all these data may need to be accessible in tabular, graphic map, and narrative formats. Conditions specific to fish and wildlife populations or knowledge of certain climatological states (El Niño-Southern Oscillation, or ENSO, for instance) are also valuable assessment tools. Observational metadata and other ancillary information such as water restrictions, passing flow requirements in regional rivers, water usage statistics, or census figures can also be critical for making effective decisions. It is also important to place present conditions in historic perspective, which might require both instrumental records and paleoclimatic or proxy records to estimate past periods of drought, as well as the relationship between regional precipitation and other indexes.
Once the present situation is well understood, the next step is to attempt to gain some insight as to whether drought conditions might worsen or ameliorate. Thus, forecasts for atmospheric and associated surface conditions need to be accessible to the decision maker, again on daily to seasonal time steps. These forecasts can be variable specific (precipitation) or for an integrated assemblage of information (drought). For those looking well beyond the present (years and decades ahead), model projections would need to be available at appropriate spatial and temporal scales. As with current conditions, outlooks need to be provided to decision makers in formats that permit rather straightforward interpretation. This includes sufficient information regarding probabilities and confidence limits.
One-stop shopping is a useful goal as long as the data and information are discoverable and understandable. With respect to drought, work is under way through the National Integrated Drought Information System (NIDIS) program to develop a Web portal that will provide a link to connect the data, scientists, and decision makers.a It is hoped that this portal, as it develops, will serve as a model for other meteorological and climatological phenomena.