A 1-km daily surface soil moisture dataset of enhanced coverage under all-weather conditions over China in 2003–2019

Surface soil moisture (SSM) is crucial for understanding the hydrological process of our earth surface. Passive microwave (PM) technique has long been the primary tool for estimating global SSM from the view of satellite, while the coarse resolution (usually >~10 km) of PM observations hampers its applications at finer scales. Although quantitative studies have been proposed for downscaling satellite PM-based SSM, very few products have been available to public that meet the qualification of 1-km resolution and daily revisit cycles under all-weather conditions. In this study, we developed one such SSM product in China with all these characteristics. The product was generated through downscaling the AMSR-E/AMSR-2 based SSM at 36-km, covering all on-orbit time of the two radiometers during 2003–2019. MODIS optical reflectance data and daily thermal infrared land surface temperature (LST) that had been gap-filled for cloudy conditions were the primary data inputs of the downscaling model, so that the “all-weather” quality was achieved for the 1-km SSM. Daily images from this developed SSM product have quasi-complete coverage over the country during April–September. For other months, the national coverage percentage of the developed product is also greatly improved against the original daily PM observations, through a specifically developed sub-model for filling the gap between seams of neighboring PM swaths during the downscaling procedure. The product is well compared against in situ soil moisture measurements from 2000+ meteorological stations, indicated by station averages of the unbiased RMSD ranging from 0.052 vol/vol to 0.059 vol/vol. Moreover, the evaluation results also show that the developed product outperforms the SMAP-Sentinel (Active-Passive microwave) combined SSM product at 1-km, with a correlation coefficient of 0.55 achieved against that of 0.40 for the latter product. This indicates the new product has great potential to be used for hydrological community, agricultural industry, water resource and environment management.

Thainema gen. nov. (Leptolyngbyaceae, Synechococcales): A new genus of simple trichal cyanobacteria isolated from a solar saltern environment in Thailand

Simple trichal types constitute a group of cyanobacteria with an abundance of novel, often cryptic taxa. Here, we investigated material collected from wet surface-soil in a saline environment in Petchaburi Province, central Thailand. A morphological comparison of the isolated strain with similar known species, as well as its phylogenetic and species delimitation analyses based on the combined datasets of other related organisms, especially simple trichal cyanobacteria, revealed that the material of this study represented an independent taxon. Using a multifaceted method, we propose that this material represents a new genus, Thainema gen. nov., belonging to the family Leptolyngbyaceae, with the type species Thainema salinarum sp. nov. This novel taxon shares similar ecological habitats with strains previously placed in the same lineage.

Analysis of the Characteristics of the Land Creeping (Slow-Moving) at Seomyeon, Suncheon-Si Area

This study was conducted to prevent land creeping by examining various features such as geology, topography, and physical characteristics, using the case of a land-crawled region. The first land creeping occurred in Seomyeon Suncheon-si in 2000, and the second occurred in 2020; the damaged surface area of the second event was approximately 21.7 times that of the first, and it was discovered Sunchoen-si Landcreep occur because of forest road cut affected. After 1 h, it was moderate at a soil depth of 20, 100, 200, and 250 cm from the surface soil, according to a measurement result of soil dispersity. It was severe at soil depths of 100, 200, and 250 cm, and the clay soil between the bedrock was mild to severe, and it was determined to be severe in locations where groundwater was leaching. The objective study area was a typical land creeping-type landslide caused by weathered rocks, and this area belonged to a type of convex terrain ground (凸) form. The land creeping occurred in the convex area (凸). As a result of analyzing the landslide hazard grade, the creeping land area is found to be different from ordinary landslides because it includes most areas of landslide hazard grade 3–5 and out of the grade. Results show that the land creeping has proceeded in the directions of S15°E, S20°E, S25°E, and S30°E, which is consistent with the direction following the flow duration of groundwater determined using the electrical resistivity survey method.

A six level automatic soil temperature measuring system

An automatic soil temperature measuring equipment is developed using four terminal thermistors. The output voltages from the six levels, i.e., 10 cm above soil surface, soil surface and 10 cm, 20 cm, 30 cm and 60 cm below the soil surface, are amplified and their multiplexed output is recorded on a chart recorder. The equipment is tested in the field and continuous observations are taken during May 1991. Temperature profiles for different hours of the day are plotted and diurnal variations of all levels are also discussed. An attempt is made to evaluate the damping depth and thence the thermal conductivity and soil heat flux.