Michael A. Palecki

TL;DR: The Level 2 Passive Soil Moisture Product (L2_SM_P) as discussed by the authors was developed by the National Aeronautics and Space Administration (NASA) soil moisture active passive (SMAP) satellite mission and is available from the Distributed Active Archive Center at the National Snow and Ice Data Center.

TL;DR: The U.S. Climate Reference Network (USCRN) as discussed by the authors consists of 114 sites across the conterminous 48 states, with additional sites in Alaska and Hawaii, where a suite of meteorological parameters are monitored, including triple redundancy for the primary air temperature and precipitation variables and for soil moisture/temperature.

TL;DR: The U.S. Climate Reference Network (USCRN) is a network of climate-monitoring stations maintained and operated by the National Oceanic and Atmospheric Administration (NOAA) to provide climate-science-quality measurements of air temperature and precipitation as discussed by the authors.

TL;DR: This article covers the development and assessment of the SMAP Level 2 Enhanced Passive Soil Moisture Product (L2_SM_P_E) and affirmed that the Single Channel Algorithm using the V-polarized TB channel (SCA-V) delivered the best retrieval performance among the various algorithms implemented for L2-SM-P, a result similar to a previous assessment.

TL;DR: The main scope of this paper is to inform readers about the evolution of the ISMN over the past decade, including a description of network and data set updates and quality control procedures.