NASA Soil Moisture

Soil Moisture data from the NASA SMAP web service, for the entire world. Data is clipped to a region 1 degree larger than than the CONUS 2 region and saved to water year netcdf files. The produced netcdf file contains 6 variables. Below are the variables and their descriptions

• TimeStamp The Date stamps of the downloaded data.

• Longitude- A single matrix representing all of the longitude points.

• Latitude- A single matrix representing all of the latitude points.

• SoilMoisture- A matrix for each date of data downloaded (in other words, a matrix for each date present in the TimeStamp variable). A whole wateryear file will contain 365 matrices in a normal year, or 366 for a leap year, one representing each day. The soil moisture data here is calculated as the mean between the AM and PM values, as downloaded from the NASA website. A RetrievalQualFlag is given for each AM data and PM data used, as described below. The latitude and longitude matrices are the same size as the Soil Moisture, RetrievalQualFlagAM, and RetrievalQualFlagPM matrices, and together, they represent the (latitude, longitude) point for which each soil moisture data point, RetrievalQualFlagAM, and RetrievalQualFlagPM, was collected.

• RetrievalQualFlagAM- A matrix for each date of data downloaded representing the data quality of the AM data collected. A whole wateryear file will contain 365 matrices in a normal year, or 366 for a leap year, one representing each day.

• RetrievalQualFlagPM- A matrix for each date of data downloaded represening the data quality of the PM data collected. A whole wateryear file will contain 365 matrices in a normal year, or 366 for a leap year, one representing each day.

On occassion, some days of data are not available from the NASA website. In these instances, a row for that date will be entered with None values for the data.

Dataset Name: nasa_smap

Data Source: nasa

Data Collection or Processing Notes:

We query data from the NASA SMAP weekly, early on Sunday mornings. All previous data, up through the most recently available data from the SMAP website, is collected.

Citations:

Please refer to the following citations for more information on this dataset and cite them if you use the data

• https://nsidc.org/data/smap/data

Extent and Resolution:

• Available Date Range: 10/1/22

• Grid: smapgrid

  • Spacial Resolution: 9000 meters

  • XY Grid Spacial Extent: 335 x 646

  • LatLon Spacial Exent: -126.88755692881833, 21.8170599154073, -64.7677149695924, 53.20274381640737

  • Origin (meters): -2208000.30881173, -1668999.65483222

  • Projection:

• Grid: conus2

  • Spacial Resolution: 1000 meters

  • XY Grid Spacial Extent: 4442 x 3256

  • LatLon Spacial Exent: -126.88755692881833, 21.8170599154073, -64.7677149695924, 53.20274381640737

  • Origin (meters): -2208000.30881173, -1668999.65483222

  • Projection: +proj=lcc +lat_1=30 +lat_2=60 +lon_0=-97.0 +lat_0=40.0000076294444 +a=6370000.0 +b=6370000

Variables

This describes the available variables of the dataset. Use the dataset, variables and temporal_resolution in python access functions as described in the Working with Gridded Data, and Working with Point Observations.

Location Variables

variable	description	temporal_resolution	units	grid	3D
latitude	Map grid points to latitude	static	degrees	smapgrid	no
longitude	Map grid points to longitude	static	degrees	smapgrid	no

Subsurface Variables

variable	description	temporal_resolution	units	grid	3D
soil_moisture	Soil moisture	daily	unitless, cm3/cm3	smapgrid, conus2	yes