TY  - JOUR
A1  - Schattan, Paul
A1  - Köhli, Markus
A1  - Schrön, Martin
A1  - Baroni, Gabriele
A1  - Oswald, Sascha Eric
T1  - Sensing area-average snow water equivalent with cosmic-ray neutrons: the influence of fractional snow cover
T2  - Water resources research
N2  - Cosmic-ray neutron sensing (CRNS) is a promising non-invasive technique to estimate snow water equivalent (SWE) over large areas. In contrast to preliminary studies focusing on shallow snow conditions (SWE <130 mm), more recently the method was shown experimentally to be sensitive also to deeper snowpacks providing the basis for its use at mountain experimental sites. However, hysteretic neutron response has been observed for complex snow cover including patchy snow-free areas. In the present study we aimed to understand and support the experimental findings using a comprehensive neutron modeling approach. Several simulations have been set up in order to disentangle the effect on the signal of different land surface characteristics and to reproduce multiple observations during periods of snow melt and accumulation. To represent the actual land surface heterogeneity and the complex snow cover, the model used data from terrestrial laser scanning. The results show that the model was able to accurately reproduce the CRNS signal and particularly the hysteresis effect during accumulation and melting periods. Moreover, the sensor footprint was found to be anisotropic and affected by the spatial distribution of liquid water and snow as well as by the topography of the nearby mountains. Under fully snow-covered conditions the CRNS is able to accurately estimate SWE without prior knowledge about snow density profiles or other spatial anomalies. These results provide new insights into the characteristics of the detected neutron signal in complex terrain and support the use of CRNS for long-term snow monitoring in high elevated mountain environments.
KW  - area-average snow monitoring
KW  - cosmic-ray neutron sensing
KW  - neutron simulations
KW  - spatial heterogeneity
KW  - fractional snow cover
Y1  - 2019
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/47628
SN  - 0043-1397
SN  - 1944-7973
VL  - 55
IS  - 12
SP  - 10796
EP  - 10812
PB  - American Geophysical Union
CY  - Washington
ER  -