NLDAS-3: Next-Generation Land Data Assimilation System to Support North American Water-Informed Decisions

To maximize the impact of NASA water missions and enable their utility for Earth Science to Action, a multi-center initiative employs NASA land surface modeling (LSM) and data assimilation (DA) tools to address evolving scientific and societal challenges of the hydrologic cycle. Employing the NASA Land Information System (LIS) framework, the goal of NASA’s North American Land DA System-Phase 3 (NLDAS-3) is to provide spatially-distributed (at 1-km grid resolution), high-quality, observations informed estimates of soil moisture and hydrology variables using the Noah with Multiple Parameterizations (Noah-MP) LSM over all of North America spanning the GPM-era time window. Driven by stakeholder and drought community requirements, NLDAS-3 is a major advancement over NLDAS-2 (~12 km) and SPoRT-LIS (~3 km), with improved forcing and multivariate [satellite] DA.

NLDAS-3 routinely assimilates satellite observations to better constrain land surface states within NoahMP, including: (1) soil moisture from SMAP, SMOS, AMSR-E, AMSR-2; (2) [passive microwave] snow from Landsat, MODIS, VIIRS, AMSR-E and AMSR2 and AI techniques; (3) vegetation indices from MODIS and VIIRS; and (4) terrestrial water storage from GRACE and GRACE-FO. DA improves modeled processes and captures human management such as irrigation, groundwater pumping, and reservoir operations. To provide high-quality, low-latency products, the NLDAS-3 run strategy includes: (1) open-loop simulations with baseline atmospheric forcing, (2) “Late-Look DA” run from 2001 onward, (3) “Early-Look DA” run extending to near-real-time, and (4) 14+ day “Early-Look Forecasts” forced by the NCEP GEFS members. In this presentation, we provide an overview of NLDAS-3, our integration strategy, real-time products, and stakeholder engagement process for drought and hydrometeorological applications.