California Drought and the North American Land Data Assimilation System (NLDAS)
Tuesday, April 21, 2015
Michael B Ek1,2, Youlong Xia2,3, Kenneth Mitchell4, Helin Wei2,3, Jiarui Dong2,3, Jesse Meng2,3, Eric F Wood5, Justin Sheffield6, Christa D Peters-Lidard7, David M Mocko7, Brian Cosgrove8, Dennis P Lettenmaier9, Kingtse C Mo10, Wesley Ebisuzaki10, Matthew Rosencrans10, Lifeng Luo11 and Eric Luebehusen12, (1)NOAA/NWS/NCEP, College Park, MD, United States, (2)Environmental Modeling Center, College Park, MD, United States, (3)IMSG, College Park, MD, United States, (4)NOAA/NWS/NCEP/EMC (retired), College Park, MD, United States, (5)Princeton University, Princeton, NJ, United States, (6)Princeton Univ, Princeton, NJ, United States, (7)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (8)NOAA/NWS/OHD, Silver Spring, MD, United States, (9)University of California Los Angeles, Department of Geography, Los Angeles, CA, United States, (10)Climate Prediction Center/NCEP, College Park, MD, United States, (11)Michigan State University, East Lansing, MI, United States, (12)USDA, OCE, Washington, DC, United States
Abstract:
The North American Land Data Assimilation System (NLDAS) is a long-term, multi-institutional project that was initiated to provide improved land surface initial conditions for weather and climate models, and subsequently expanded to support multiple applications related to land surface hydrology, such as the ongoing drought situation in California. NLDAS consists of 30-year retrospective (1979-2008) and near real-time (2009-present) runs of four land surface models (LSMs) with atmospheric forcing to drive the LSMs from the North American Regional Reanalysis (NARR; 1979-2008) and the Regional Climate Data Assimilation System (R-CDAS, the real-time extension to NARR; 2009-present), plus daily gauge-based, radar and satellite temporally disaggregated precipitation observations from the NCEP Climate Prediction Center. Output includes energy and water fluxes, and land state variables, such as soil moisture, evaporation, streamflow, and snow pack. Anomalies and percentiles from the 30-year climatologies have been comprehensively evaluated against many different observational data sets, and are used to support drought monitoring and prediction tasks such as the U.S. Drought Monitor, NCEP Climate Prediction Center drought information, and activities of the National Integrated Drought Information System. The NCEP Environmental Modeling Center lead the operational implementation in August 2014 of NLDAS, which now provides more reliable and timely products. This presentation summarizes experiences of NLDAS, status and format of current products, and future plans, with particular focus on the use of NLDAS to assess the development and persistence of drought conditions in California.
