Online Tools to Investigate Uncertainties in Satellite-derived Global Precipitation Products

Precipitation is difficult to measure and predict. Each year droughts and floods can cause severe property damages and human casualties around the world. Accurate measurement and forecast are important for mitigation and preparedness efforts. Significant progress has been made over the past decade in satellite-based precipitation product development. In particular, products' spatial and temporal resolutions as well as timely availability have been improved by blended techniques. Their resulting products are widely used in various research and applications. However biases and uncertainties are common among precipitation products and obstacles exists to prevent quickly obtaining knowledge of product characteristics, such as, data quality, biases and behavior at a local or regional scale, namely user defined areas or points of interest. We have developed online prototypes in the GIOVANNI TRMM Online Visualization and Analysis System (TOVAS) to address these issues. There are four online tools to allow inter-comparing 3-hourly, daily, monthly and climatology of the existing and previous versions of TRMM Multi-satellite Precipitation Analysis (TMPA) products (3B42, 3B43) and their near-real-time products (3B42RT). For TRMM monthly products, users can inter-compare them with their current and previous versions as well. Users can use these tools to analyze the products, generate plots and download customized data for further analysis, e.g. comparing their gauge data. Examples from these tools will be presented. The future plans include 1) integration of the IPWG (International Precipitation Working Group) Validation Algorithms/statistics in TOVAS; 2) add more Level-3 monthly TRMM products; and 3) add more climatology datasets derived from Level-3 TRMM monthly products.