Drought Indices Based on the Climate Forecast System Reanalysis and Ensemble NLDAS

Drought indices derived from the Climate Forecast System Reanalysis (CFSR) are compared with indices derived from the ensemble North American Land Data Assimilation System (NLDAS) and the North American Regional Reanalysis (NARR) over the United States. Uncertainties in soil moisture, runoff, and ev...

Full description

Saved in:
Bibliographic Details
Published in:Journal of hydrometeorology 2011-04, Vol.12 (2), p.181-205
Main Authors: Mo, Kingtse C., Long, Lindsey N., Xia, Youlong, Yang, S. K., Schemm, Jae E., Ek, Michael
Format: Article
Language:English
Subjects:
Atmospheric models
Climate models
Drought
Freshwater
Hydrometeorology
Marine
Precipitation
Seasons
Soil water
Space research
Surface runoff
Vegetation
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Drought indices derived from the Climate Forecast System Reanalysis (CFSR) are compared with indices derived from the ensemble North American Land Data Assimilation System (NLDAS) and the North American Regional Reanalysis (NARR) over the United States. Uncertainties in soil moisture, runoff, and evapotranspiration (E) from three systems are assessed by comparing them with limited observations, includingEfrom the AmeriFlux data, soil moisture from the Oklahoma Mesonet and the Illinois State Water Survey, and streamflow data from the U.S. Geological Survey (USGS). The CFSR has positive precipitation (P) biases over the western mountains, the Pacific Northwest, and the Ohio River valley in winter and spring. In summer, it has positive biases over the Southeast and large negative biases over the Great Plains. These errors limit the ability to use the standardized precipitation indices (SPIs) derived from the CFSR to measure the severity of meteorological droughts. To compare with thePanalyses, the Heidke score for the 6-month SPI derived from the CFSR is on average about 0.5 for the three-category classification of drought, floods, and neutral months. The CFSR has positiveEbiases in spring because of positive biases in downward solar radiation and high potential evaporation. The negativeEbiases over the Great Plains in summer are due to lessPand soil moisture in the root zone. The correlations of soil moisture percentile between the CFSR and the ensemble NLDAS are regionally dependent. The correlations are higher over the area east of 100°W and the West Coast. There is less agreement between them over the western interior region.
ISSN:1525-755X
1525-7541
DOI:10.1175/2010jhm1310.1