Understanding radar backscatter sensitivity to vegetation water dynamics: Sub-daily variations in ground-based experiments

Observing vegetation water dynamics from space offers insights into plant-water relations and water and carbon fluxes across ecosystems at local to global scales. A promising technique to observe water in the vegetation layer is radar, an active form of microwave remote sensing. Interactions between microwaves and vegetation material depend on...

Microwave remote sensing for agricultural drought monitoring: Recent developments and challenges

Agricultural droughts are extreme events which are often a result of interplays between multiple hydro-meteorological processes. Therefore, assessing drought occurrence, extent, duration and intensity is complex and requires the combined use of multiple variables, such as temperature, rainfall, soil moisture (SM) and vegetation state. The...

Perspective on satellite-based land data assimilation to estimate water cycle components in an era of advanced data availability and model sophistication

The beginning of the 21^st century is marked by a rapid growth of land surface satellite data and model sophistication. This offers new opportunities to estimate multiple components of the water cycle via satellite-based land data assimilation (DA) across multiple scales. By resolving more processes in land surface models and by...

The Effect of Water Vapor Originating from Land on the 2018 Drought Development in Europe

The 2018 summer drought in Europe was particularly extreme in terms of intensity and impact due to the combination of low rainfall and high temperatures. However, it remains unclear how this drought developed in time and space in such an extreme way. In this study we aimed to get a better understanding of the role of land–atmosphere interactions...

Evaluation of the Drivers Responsible for Flooding in Africa

Africa is severely affected by floods, with an increasing vulnerability to these events in the most recent decades. Our improved preparation against and response to this hazard would benefit from an enhanced understanding of the physical processes at play. Here, a database of 399 African stream gauges is used to analyze the seasonality of...

Improving ASCAT Soil Moisture Retrievals With an Enhanced Spatially Variable Vegetation Parameterization

This study investigates the performance of the TU Wien soil moisture retrieval (TUW-SMR) algorithm by adapting the strength of the vegetation correction. The semiempirical change detection method TUW-SMR exploits the multiangle backscatter observations from spaceborne fan-beam scatterometer systems in order to derive surface soil moisture...

Root-soil inter actions adaptation strategies of plants in response to soil water availability

We study the coupled action of water uptake and root development of maize in potting soil under greenhouse conditions. To this end, we apply subsurface irrigation strategies that are constant over weeks. We perform synchronous realtime measurements of the co-evolving soil moisture fields and root distributions. Will constant irrigation...

Mapping high-resolution soil moisture and properties using distributed temperature sensing data and an adaptive particle batch smoother

This study demonstrated a new method for mapping high-resolution (spatial: 1 m, and temporal: 1 h) soil moisture by assimilating distributed temperature sensing (DTS) observed soil temperatures at intermediate scales. In order to provide robust soil moisture and property estimates, we first proposed an adaptive particle batch smoother...

Determining soil moisture and soil properties in vegetated areas by assimilating soil temperatures

This study addresses two critical barriers to the use of Passive Distributed Temperature Sensing (DTS) for large-scale, high-resolution monitoring of soil moisture. In recent research, a particle batch smoother (PBS) was developed to assimilate sequences of temperature data at two depths into Hydrus-1D to estimate soil moisture as well as...

Moisture in the topsoil: From large-scale observations to small-scale process understanding

The boundary that separates the earth from the atmosphere is a crucial zone of study for meteorology and hydrology. Here, solar energy is partitioned into sensible heat which drives atmospheric circulation, latent heat needed for evaporation from the soil and transpiration of vegetation, and soil heat which warms the subsurface. Precipitation is...

Mapping variability of soil water content and flux across 1–1000 m scales using the Actively Heated Fiber Optic method

The Actively Heated Fiber Optic (AHFO) method is shown to be capable of measuring soil water content several times per hour at 0.25 m spacing along cables of multiple kilometers in length. AHFO is based on distributed temperature sensing (DTS) observation of the heating and cooling of a buried fiber-optic cable resulting from an electrical...

Inferring catchment precipitation by doing hydrology backward: A test in 24 small and mesoscale catchments in Luxembourg

The complexity of hydrological systems and the necessary simplification of models describing these systems remain major challenges in hydrological modeling. Kirchner's (2009) approach of inferring rainfall and evaporation from discharge fluctuations by “doing hydrology backward” is based on the assumption that catchment behavior can be...

Surface and subsurface water from space: On the integration of microwave remote sensing observations with flood prediction systems

The technique of active microwave remote sensing has made much progress toward its high potential to monitor water storage changes in terrestrial surface and subsurface water bodies at various spatial and temporal scales. The number of studies demonstrating the support these data can offer in hydrological and hydraulic model building, model...

Feasibility of soil moisture estimation using passive distributed temperature sensing

Through its role in the energy and water balances at the land surface, soil moisture is a key state variable in surface hydrology and land?atmosphere interactions. Point observations of soil moisture are easy to make using established methods such as time domain reflectometry and gravimetric sampling. However, monitoring large?scale variability...

Regional vegetation water effects on satellite soil moisture estimations for West Africa

Soil moisture information is a vital parameter for water resources planning and food production. In particular for West Africa, where income largely depends on rainfed agriculture, reliable information on available soil water is required for modeling and prediction. Over large areas and, specifically, for data scarce regions, satellite soil...

Hydrotope-Based Protocol to Determine Average Soil Moisture Over Large Areas for Satellite Calibration and Validation With Results From an Observation Campaign in the Volta Basin, West Africa

In West Africa, which is an extremely moisturelimited region, soil water information plays a vital role in hydrologic and meteorologic modeling for improved water resource planning and food security. Recent and upcoming satellite missions, such as SMOS and MetOp, hold promise for the regional observation of soil moisture. The resolution of the...