SMuK 2023 – wissenschaftliches Programm

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UP: Fachverband Umweltphysik

UP 4: Aerosols & Hydrological Cycle

UP 4.6: Vortrag

Mittwoch, 22. März 2023, 15:15–15:30, MOL/0213

Validation potential for Remote Sensing soil moisture products using Cosmic-Ray Neutron Sensing — •Markus Köhli, Jannis Weimar, and Ulrich Schmidt — Physikalisches Institut, Heidelberg University

The novel method of Cosmic-ray neutron sensing (CRNS) allows for non-invasive soil moisture measurements at a hectometer scaled footprint. This technique relies on the measurement of neutrons originating from cosmic-ray induced air showers. The key characteristic of the method is the exceptionally high moderation strength of hydrogen. It slows down fast neutrons whereas other heavier elements independent of the chemical composition rather reflect them. The result is an inverse relation of the above-ground neutron intensity to soil moisture. Due to neutrons being transported over the air over hundreds of meters, the measurement is representative for an area on the scale of hectares. In the recent years the interest was set to understanding neutron transport by Monte-Carlo simulations for complex environmental topographies. Its remarkable performance in signal interpretation allows for a promising prospect of more comprehensive data quality. This especially addresses mobile applications, which is the current focus of development. With roving it is possible to cover the scale of one square kilometer per day with one instrument. Satellite-based products can specifically profit from data assimilation of CRNS-based representative measurements of soil moisture. With its large integral footprint and its penetration depth of several decimeters, high-quality data sets can be obtained as ground truthing for remote sensing products.