An Interactive Web-based Data Analysis tool in support of the land data assimilation scheme (LDAS) Project

Changes in the weather and climate affect virtually all aspects of life. Floods and snowstorms can cripple cities, while heat waves and droughts can have large impacts on agricultural production and water usage. In each of these events, it is not only the atmosphere that is an important factor, but also the way in which the atmosphere interacts with the land surface below. As such, many numerical weather prediction (NWP) models that are used to forecast such events have incorporated land surface models (LSMs) into their programming. Although this change has increased forecast accuracy, the majority of NWP models cycle mainly on internally generated land surface data and thus are affected by errors in internal forcing and model mechanics. Such errors can lead to unrealistic stores of moisture and energy in the LSM and so degrade the quality of forecasts produced by the NWP model. An effective way to reduce these errors in storage is to use land data assimilation schemes (LDASs)-land surface models that are forced in large part by observations-to provide the forecast model with a continually updating, accurate snapshot of the land-surface state.

Over the past year, the LDAS project (involving participants from the NASA Goddard Space Flight Center, the National Weather Service's National Centers for Environmental Prediction and Office of Hydrology, Princeton University and the University of Washington) has been developing just such a land data assimilation scheme. Running on a 1/8th-degree grid in a near real-time fashion, the scheme is currently forced by terrestrial precipitation data, space-based radiation data and ETA model output. In order to create an optimal scheme, the project has involved several LSMs from the institutions named above, and may eventually include several more. One of the main tools used to coordinate this research effort has been the LDAS project web site (http://ldas.gsfc.nasa.gov). The site has served as a clearinghouse for project-related data sets and information, and features a real-time image generator (RIG). A fully interactive and web accessible tool, the RIG is based on Perl, JAVA, FORTRAN and UNIX, and has proven to be an effective, powerful means to explore and compare model output from the various LDAS LSMs.

By making use of a network-enabled computer, this poster will highlight the features of this LDAS project web site. A demonstration of the RIG will be conducted which will use results from the Mosaic LSM to show that it is possible to create an accurate, real-time snapshot of land-surface states using assimilated observations.

¹SAIC General Sciences Corporation

²NASA Goddard Space Flight Center

³Raytheon ITSS