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Soil moisture (SM) plays an important role in regulating regional weather and climate. However, the simulations of SM in current land surface models (LSMs) contain large biases and model spreads. One primary reason contributing to such model biases could be the misrepresentation of soil texture in LSMs, since current available large‐scale soil texture data are often generated from extrapolation algorithm based on a scarce number of in‐situ geological measurements. Fortunately, recent advancements in satellite technology provide a unique opportunity to constrain the soil texture data sets by introducing observed information at large spatial scales. Here, two major soil texture baseline data sets (Global Soil Data sets for Earth system science, GSDE and Harmonized World Soil Data from Food and Agriculture Organization, HWSD) are optimized with satellite‐estimated soil hydraulic parameters. The optimized soil maps show increased (decreased) sand (clay) content over arid regions. The soil organic carbon (SOC) content increases globally especially over regions with dense vegetation cover. The optimized soil texture data sets are then used to run simulations in one example LSM, that is, Noah LSM with Multiple Parameters. Results show that the simulated SM with satellite‐optimized soil texture maps is improved at both grid and in‐situ scales. Intercase comparison analyses show the SM improvement differs between simulations using different soil maps and soil hydraulic schemes. Our results highlight the importance of incorporating observation‐oriented calibration on soil texture in current LSMs. This study also joins the call for a better soil profile representation in the next generation of Earth System Models (ESMs). Plain Language Summary: Soil moisture (SM) is important for weather and climate but is often poorly simulated by Land Surface Models (LSMs). One possible reason could be the inappropriate representation of soil texture maps utilized in LSMs since current gridded soil texture maps are often derived from a limited number of in‐situ measurements. In this study, we leverage the benefits of modern satellite products and land surface theories to improve several major global soil texture maps, and use the calibrated soil maps to improve SM simulation in one example LSM. Results show increased sand content over arid areas while the results for clay content show the opposite pattern. The SOC result shows an overall increase over the entire globe but is more evident in dense vegetation land covers. The model simulated SM using the calibrated soil maps generally outperforms those with the baseline soil maps. The improvement is more significant in the experiment with soil maps considering SOC. Our results here provide successful evidence for constraining soil texture data from large‐scale observations. We also show that observation‐oriented calibration on soil texture maps is necessary for a better land surface simulation, which is critically important for the development of ESMs. Key Points: Satellite Soil moisture (SM) data is used to improve the representativeness of two major soil texture data sets at the global scaleSM simulations using the updated soil maps outperform those using the baseline soil texture productsSM improvement is more significant in simulations considering soil organic carbon (SOC) [ABSTRACT FROM AUTHOR]

© 2015. American Geophysical Union. All Rights Reserved. The impacts of droughts on the Amazon ecosystem have been broadly discussed in recent years, but a comprehensive understanding of the consequences is still missing. In this study, we show evidence of a fragile hydrological equilibrium in the western Amazon. While drainage systems located near the equator and the western Amazon do not show water deficit in years with average climate conditions, this equilibrium can be broken during drought events. More importantly, we show that this effect is persistent, taking years until the normal hydrological patterns are reestablished. We show clear links between persistent changes in forest canopy structure and changes in hydrological patterns, revealing physical evidence of hydrological mechanisms that may lead to permanent changes in parts of the Amazon ecosystem. If prospects of increasing drought frequency are confirmed, a change in the current hydroecological patterns in the western Amazon could take place in less than a decade.

Floodplain societies decide whether to protect themselves against floods (fight), live with floods (adapt), or adopt an approach that represents some combination of the two. The formation of a levee system is an important factor in determining whether a society fights or adapts to floods; however, these factors have been considered fixed boundaries in previous studies in human–flood interactions. We analyze a levee system transformation process covering the past century, from the indigenous ring-type levee system with floods to modern continuous levees against floods in the Kiso River basin in Japan by applying a historical sociohydrological approach. The results show degradation processes of the indigenous levee system and traditional communities alongside the installation of modern continuous levees, and a trade-off relationship was observed between the lengths of both. There are interactions between the levee systems and the human–water system through various water uses and different-scale components, and the dynamics within the region are connected to external socioeconomic trends through the installed modern levees and institutions. [ABSTRACT FROM AUTHOR]

Floodplain societies decide whether to protect themselves against floods (fight), live with floods (adapt), or a combination of the two. The formation of a levee system is an important factor in determining whether a society fight or adapt to flood; however, these factors have been considered as fixed boundaries in previous studies in human-flood interaction. We analyse a levee system transformation process covering the past century, from the indigenous ring-type levee system with floods to modern continuous levees against floods in the Kiso River basin, Japan, by applying a historical sociohydrological approach. The results show degradation processes of the indigenous levee system and traditional communities alongside the installation of modern continuous levees, and a trade-off relationship was observed between the lengths of both. There are interactions between the levee systems and the human-water system through various water uses and different scale components, and the dynamics within the region are connected to external socioeconomic trends through the installed modern levees and institutions. [ABSTRACT FROM AUTHOR]