BST/NOAA PSL Level 3 UAS Soil Moisture, Digital Elevation, Normalized Difference Vegetative Index, and Surface Temperature for SPLASH

This dataset contains uncrewed aircraft systems (UAS) high-resolution data of soil moisture at the 0-5 cm soil depth, normalized difference vegetation index (NDVI), surface temperature, and digital elevation for the Study of Precipitation, the Lower Atmosphere, and Surface for Hydrology (SPLASH) campaign sponsored by the National Oceanic and Atmospheric Administration (NOAA).  While Level 2 provides each product at their highest retrieved spatial resolution, Level 3 provides all four products on a common grid at each flight location. These data were collected near Avery Picnic (38.972425^oN,106.996855^oW) and Kettle Ponds (38.942005^oN,106.973006^oW) in the East River Watershed in Colorado from a series of flights starting on June 1st, 2022 and ending October 19th, 2022.  Soil moisture measurements were retrieved using the Lobe Differencing Correlation Radiometer (LDCR) which is a L-Band (1-2 GHz) microwave radiometer and was flown on the E2 and S2 aerial platforms operated by Black Swift Technologies, Inc.  

Each Level 3 NetCDF file contains all four UAS parameters at a flight location interpolated to a common rectilinear grid at ~50 cm resolution.   Soil moisture retrievals were downscaled to a higher resolution grid using bilinear interpolation while surface temperature, NDVI, and digital elevation were upscaled to a lower resolution grid using conservative interpolation. The data was regridded using the Python package xESMF which is based on code developed for the Earth System Modeling Framework (ESMF) project. 

The file name convention for the Level 3 NetCDF files is as follows.

uas_L3_yyyymmdd_hhmmss_vx.x.nc

where

L3 = Level 3 data 

yyyymmdd = year,month,day

hhmmss = hour,minute,second

x.x  = version number 

Time is the flight start time in UTC.

Version number description is provided in the NetCDF global attributes.

Note that each flight location using the E2 aerial platform required two flights with different starting flight times for the soil moisture and the other three products.  The flight start time is the time of the first flight. The total time for the two flights at each location was ~1 hour.