GRACE-based Root Zone Soil Moisture

Federal Geographic Data Committee (FGDC) Metadata:


Identification_Information:
Citation:
Citation_Information:
Originator: NASA
Publication_Date: 20120109
Title: GRACE-based Root Zone Soil Moisture
Edition:
Geospatial_Data_Presentation_Form:
Series_Information:
Series_Name:
Issue_Identification:
Publication_Information:
Publication_Place:
Publisher: National Drought Mitigation Center
Other_Citation_Details:
Online_Linkage: http://drought.unl.edu/MonitoringTools/NASAGRACEDataAssimilation.aspx
Description:
Abstract:
Groundwater and Soil Moisture Conditions from GRACE Data Assimilation ****These are experimental products that are still being evaluated and improved. There are known errors in certain regions which we are currently working to resolve. We encourage your specific, constructive feedback as this phase of development proceeds.**** Scientists at NASA’s Goddard Space Flight Center generate groundwater and soil moisture drought indicators each week. They are based on terrestrial water storage observations derived from GRACE satellite data andintegrated with other observations, using a sophisticated numerical model of land surface water and energy processes. The drought indicators describe current wet or dry conditions, expressed as a percentile showing the probability of occurrence within the period of record from 1948 to the present, with lower values (warm colors) meaning dryer than normal, and higher values (blues) meaning wetter than normal. These are provided as both images and binary data files. Non-Technical Description The maps are based on data from NASA's Gravity Recovery and Climate Experiment (GRACE) satellites, which detect small changes in the Earth's gravity field caused by the redistribution of water on and beneath the land surface. The paired satellites travel about 137 miles (220 km) apart and record small changes in the distance separating them as they encounter variations in the Earth's gravitational field. To make the maps, scientists use a sophisticated computer model that combines measurements of water storage from GRACE with a long-term meteorological dataset to generate a continuous record of soil moisture and groundwater that stretches back to 1948. The meteorological data includes precipitation, temperature, solar radiation and other ground- and space-based measurements. The maps are meant to depict drought associated with climatic variability, as opposed to depletion of aquifers due to groundwater withdrawals that exceed recharge. There are several aquifers in the U.S. that have been depleted in that way over the past century, such as the southern half of the High Plains aquifer in the central U.S. If the groundwater drought indicator map accounted for human-induced depletion, such regions would be red all the time, which would not be useful for evaluating current wetness conditions relative to previous conditions. On time scales of weeks to ten years, we expect that our maps will be reasonably well correlated with measured water table variations over spatial scales of 25 km (16 miles) or more. However, users should not assume a direct correspondence between these groundwater percentiles and measured groundwater levels over multiple decades. The color-coded maps show how much water is stored now as a probability of occurrence in the record from 1948 to the present. Technical Description Launched in 2002, NASA’s Gravity Recovery and Climate Experiment satellites are unique in their ability to measure variations in water stored at all levels above and within the land surface (terrestrial water storage). However, the spatial (>150,000 km2) and temporal (monthly with a significant time lag) resolutions of the GRACE fields limit their direct applicability for drought assessment. In order to increase the resolution, eliminate the time lag, and isolate groundwater and other components from total terrestrial water storage, scientists at NASA/GSFC integrate the GRACE data with other ground- and space-based meteorological observations (precipitation, solar radiation, etc.) within the Catchment Land Surface Model, using Ensemble Kalman smoother type data assimilation (Zaitchik et al., 2008). The resulting fields of soil moisture and groundwater storage variations are then used to generate drought indicators based on the cumulative distribution function of wetness conditions during 1948-2009 simulated by the Catchment model. Houborg et al. (2011) provide complete details on GRACE-based drought indicator product generation. credit: NASA, The National Drought Mitigation Center, Matthew Rodell
Purpose:
Not Available
Supplemental_Information:
REFERENCE: Houborg, R., M. Rodell, B. Li, R. Reichle, and B. Zaitchik 2011 Drought indicators based on model assimilated GRACE terrestrial water storage observations Wat. Resour. Res.
Supplemental_Information:
REFERENCE: Zaitchik, B.F., M. Rodell, and R.H. Reichle 2008 Assimilation of GRACE terrestrial water storage data into a land surface model: results for the Mississippi River Basin 9 3 J. Hydrometeor 535-548 doi:10.1175/2007JHM951.1
Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 19480101
Ending_Date: 20091231
Currentness_Reference:Unknown
Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 20120109
Ending_Date: 20120109
Currentness_Reference:Unknown
Status:
Progress: Complete
Maintenance_and_Update_Frequency: As needed
Spatial_Domain:
Description_of_Geographic_Extent:
Bounding_Coordinates:
West_Bounding_Coordinate: -130.0
East_Bounding_Coordinate: -55.0
North_Bounding_Coordinate: 50.0
South_Bounding_Coordinate: 20.0
Keywords:
Theme:
Theme_Keyword_Thesaurus: GCMD SCIENCE PARAMETERS
Theme_Keyword_Thesaurus: GCMD PLATFORM
Theme_Keyword_Thesaurus: GCMD INSTRUMENT
Theme_Keyword_Thesaurus: ANCILLARY KEYWORDS
Theme_Keyword_Thesaurus: ISO TOPIC CATEGORY
Theme_Keyword: EARTH SCIENCE > AGRICULTURE > SOILS > SOIL MOISTURE/WATER CONTENT
Theme_Keyword: EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC PHENOMENA > DROUGHT
Theme_Keyword: EARTH SCIENCE > LAND SURFACE > SOILS > SOIL MOISTURE/WATER CONTENT
Theme_Keyword: EARTH SCIENCE > CLIMATE INDICATORS > LAND SURFACE/AGRICULTURE INDICATORS > SATELLITE SOIL MOISTURE INDEX
Theme_Keyword: GRACE > GRAVITY RECOVERY AND CLIMATE EXPERIMENT
Theme_Keyword: GRACE II > GRAVITY RECOVERY AND CLIMATE EXPERIMENT II
Theme_Keyword: GRACE LRR > LASER RETRO-REFLECTOR
Theme_Keyword: GRACE INTERFEROMETER
Theme_Keyword: Climate Diagnostics
Theme_Keyword: Nasa Code 610
Theme_Keyword: FARMING
Theme_Keyword: CLIMATOLOGY/METEOROLOGY/ATMOSPHERE
Theme_Keyword: GEOSCIENTIFIC INFORMATION
Place:
Place_Keyword_Thesaurus: GCMD
Place_Keyword: CONTINENT > NORTH AMERICA > UNITED STATES OF AMERICA
Access_Constraints: Not Available
Use_Constraints:
Not Available
Browse_Graphic:
Browse_Graphic_File_Name: http://drought.unl.edu/nasa_grace/GRACE_RTZSM.png
Browse_Graphic_File_Description:
Browse_Graphic_File_Type: PNG
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Data_Quality_Information:
Attribute_Accuracy:
Attribute_Accuracy_Report:
Not Available
Logical_Consistency_Report:
Not Available
Completeness_Report:
Not Available
Lineage:
Process_Step:
Process_Description:
Not Available
Process_Date: Unknown
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Spatial_Reference_Information:
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Distribution_Information:
Distributor:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: UNE-L/NDMC > National Drought Mitigation Center, University of Nebraska, Lincoln
Contact_Person: MATTHEW RODELL
Contact_Position: DATA CENTER CONTACT
Contact_Address:
Address_Type: Mailing and Physical Address
Address: NASA/GSFC
Address: Hydrological Sciences Branch - Code 614.3
City: Greenbelt
State_or_Province: MD
Postal_Code: 20771
Country: USA
Contact_Voice_Telephone: 301-286-9143
Contact_Facsimile_Telephone: 301-286-8624
Contact_Electronic_Mail_Address: Matthew.Rodell@nasa.gov
Resource_Description: NASA_GRACE-based_RootZone_Soil_Moisture1948-2009
Distribution_Liability:
Not Available
Standard_Order_Process:
Digital_Form:
Digital_Transfer_Information:
Format_Name: Not Available
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Network_Address:
Network_Resource_Name:
http://drought.unl.edu/
Access_Instructions:
DATA CENTER URL
Digital_Transfer_Option:
Fees: Not Available
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Metadata_Reference_Information:
Metadata_Date: 20120111
Metadata_Review_Date: 20120111
Metadata_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: GCMD User Support Office
Contact_Organization: NASA Global Change Master Directory
Contact_Address:
Address_Type: Mailing and Physical Address
Address: Not Available
City: Lanham
State_or_Province: MD
Postal_Code: 20706
Country: USA
Contact_Voice_Telephone: Not Available
Contact_Electronic_Mail_Address: gcmduso@gcmd.gsfc.nasa.gov
Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata
Metadata_Standard_Version: FGDC-STD-001-1998
Metadata_Time_Convention: local time
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