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Land Surface Precipitation and Hydrology in MERRA-2
NTRS Full-Text: Click to View  [PDF Size: 4.6 MB]
Author and Affiliation:
Reichle, R.(NASA Goddard Space Flight Center, Greenbelt, MD, United States)
Koster, R.(NASA Goddard Space Flight Center, Greenbelt, MD, United States)
Draper, C.(NASA Goddard Space Flight Center, Science Collaborator, Greenbelt, MD, United States)
Liu, Q.(Science Systems and Applications, Inc., Greenbelt, MD, United States)
Girotto, M.(Universities Space Research Association, Greenbelt, MD, United States)
Mahanama, S.(Science Systems and Applications, Inc., Greenbelt, MD, United States)
De Lannoy, G.(NASA Goddard Space Flight Center, Science Collaborator, Greenbelt, MD, United States)
Partyka, G.(Science Systems and Applications, Inc., Greenbelt, MD, United States)
Abstract: The Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2), provides global, 1-hourly estimates of land surface conditions for 1980-present at 50-km resolution. Outside of the high latitudes, MERRA-2 uses observations-based precipitation data products to correct the precipitation falling on the land surface. This paper describes the precipitation correction method and evaluates the MERRA-2 land surface precipitation and hydrology. Compared to monthly GPCPv2.2 observations, the corrected MERRA-2 precipitation (M2CORR) is better than the precipitation generated by the atmospheric models within the cyclingMERRA-2 system and the earlier MERRA reanalysis. Compared to 3-hourlyTRMM observations, the M2CORR diurnal cycle has better amplitude but less realistic phasing than MERRA-2 model-generated precipitation. Because correcting the precipitation within the coupled atmosphere-land modeling system allows the MERRA-2 near-surface air temperature and humidity to respond to the improved precipitation forcing, MERRA-2 provides more self-consistent surface meteorological data than were available from the earlier, offline MERRA-Land reanalysis. Overall, MERRA-2 land hydrology estimates are better than those of MERRA-Land and MERRA. A comparison against GRACE satellite observations of terrestrial water storage demonstrates clear improvements in MERRA-2 over MERRA in South America and Africa but also reflects known errors in the observations used to correct the MERRA-2 precipitation. The MERRA-2 and MERRA-Land surface and root zone soil moisture skill vs. in situ measurements is slightly higher than that of ERA-Interim Land and higher than that of MERRA (significantly for surface soil moisture). Snow amounts from MERRA-2 have lower bias and correlate better against reference data than do those of MERRA-Land and MERRA, with MERRA-2 skill roughly matching that of ERA-Interim Land. Seasonal anomaly R values against naturalized stream flow measurements in the United States are, on balance, highest for MERRA-2 and ERA-Interim Land, somewhat lower for MERRA-Land, and lower still for MERRA.
Publication Date: Nov 13, 2017
Document ID:
20170011571
(Acquired Dec 18, 2017)
Subject Category: EARTH RESOURCES AND REMOTE SENSING; GEOSCIENCES (GENERAL)
Report/Patent Number: GSFC-E-DAA-TN50130
Document Type: Oral/Visual Presentation
Meeting Information: International Conference on Reanalysis; 5th; 13-17 Nov. 2017; Rome; Italy
Meeting Sponsor: European Centre for Medium-Range Weather Forecasts; Reading, United Kingdom
Contract/Grant/Task Num: NNG17HP01C; NNG11HP16A
Financial Sponsor: NASA Goddard Space Flight Center; Greenbelt, MD, United States
Organization Source: NASA Goddard Space Flight Center; Greenbelt, MD, United States
Description: 20p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright; Public use permitted
NASA Terms: ATMOSPHERIC MODELS; ATMOSPHERIC TEMPERATURE; EARTH SURFACE; HYDROLOGY; METEOROLOGICAL PARAMETERS; PRECIPITATION (METEOROLOGY); SATELLITE OBSERVATION; SOIL MOISTURE; SURFACE PROPERTIES; ANOMALIES; BIAS; DIURNAL VARIATIONS; FLOW MEASUREMENT; POLAR REGIONS; WATER
Other Descriptors: M2CORR; MERRA-
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