Comparison and Downscale of AMSR2 Soil Moisture Products with In Situ Measurements from the SCAN–NRCS Network over Puerto Rico

Abstract

Abstract:A continuous spatio-temporal database of accurate soil moisture (SM) measurements is an important asset for agricultural activities, hydrologic studies, and environmental monitoring. The Advanced Microwave Scanning Radiometer 2 (AMSR2), which was launched in May 2012, has been providing SM data globally with a revisit period of two days. It is imperative to assess the quality of this data before performing any application. Since resources of accurate SM measurements are very limited in Puerto Rico, this research will assess the quality of the AMSR2 data by comparing it with ground-based measurements, as well as perform a downscaling technique to provide a better description of how the sensor perceives the surface soil moisture as it passes over the island. The comparison consisted of the evaluation of the mean error, root mean squared error, and the correlation coefficient. Two downscaling techniques were used, and their performances were studied. The results revealed that AMSR2 products tend to underestimate soil moisture. This is due to the extreme heterogeneous distributions of elevations, vegetation densities, soil types, and weather events on the island. This research provides a comprehensive study on the accuracy and potential of the AMSR2 products over Puerto Rico. Further studies are recommended to improve the AMSR2 products.

Forward Simulation of Multi-Frequency Microwave Brightness Temperature over Desert Soils in Kuwait and Comparison with Satellite Observations

“…The variations of Tbs in Figure 9c is mainly due to LST differences. This is clearly seen from AMSR2 (18.7) and SSM/I (19), which have almost the same frequency; however, the Tb of AMSR2, which has a passing time at 1:30 p.m., is more than the Tb of SSM/I, which has a passing time at 6:30 p.m. The sensitivity of Tbv to variations in LST is shown clearly from the high values of Mean Difference MD and Root Mean Square Deviation RMSD in Table 3a,b.…”

“…The SMOS satellite mission also uses the low microwave L band frequency to measure soil moisture [12,13]. Attempts to retrieve soil moisture from higher frequencies utilized by such as the SSM/I and AMSR2 satellites were conducted and investigated in several studies [14][15][16][17][18][19].…”

Water and Energy Balance Model GOES-PRWEB: Development and Validation

“…A validation study in which only a single value of soil moisture is used may be insufficient. The need for a greater number of samples increases with coarser resolution soil moisture remote sensing products, such as the Advanced Microwave Scanning Radiometer 2 (AMSR2) with a 25 km spatial resolution ( [68]) and the soil moisture active passive (SMAP) mission with a 9 km spatial resolution ( [69]).…”

“…Ref. [68] compared the AMSR2 soil moisture product with the NRCS SCAN stations in Puerto Rico. They used two down-scaling techniques to improve the comparisons relative to the raw AMSR2 soil moisture data.…”

“…The mean error for the Juana Diaz Experimental station was −7.5% for the AMSR2 model vs. −2.13% for GOES-PRWEB in this study (Figure 6). It should be noted that [68] filtered the soil moisture data not using days when the difference between the satellite and station soil moisture values were greater than +/− 0.15. Furthermore, [70] developed an algorithm to estimate soil moisture using a self-organized artificial neural network (ANN) and a stochastic transfer function model for estimating soil moisture at 20 cm depth.…”