Peak grain forecasts for the US High Plains amid withering waters

ACKNOWLEDGMENTS. This paper stems from discussions during the Ettersburg Ecohydrology Workshop in Germany (October 2018), with the corresponding manuscript preparation ensuing in subsequent months. The workshop was funded by the UNIDEL Foundation, Inc. and the University of Delaware. Accordingly, partial support for this paper derived from funding for the workshop. A.M. was supported by the US NSF (Grants NSF-AGS-1644382 and NSF-IOS-175489).Peer reviewedPublisher PD

Time scale and intensity dependency in multiplicative cascades for temporal rainfall disaggregation

[1] Multiplicative random cascades (MRCs) can parsimoniously generate highly intermittent patterns similar to those in rainfall. The elemental MRC model parameter is the cascade weight, which determines how rainfall at one scale is partitioned at the next smallest scale in the cascade. While it is known that the probability density of these weights may vary with both time scale and rainfall intensity, nearly all previous studies have considered either time scale or intensity separately. We examined the simultaneous dependency of the weights on both factors and assessed the impacts of explicitly including these dependencies in the MRC model. On the basis of the observed relationships between cascade weights and time scale and intensity, four progressively more “dependent” models were constructed to disaggregate a long time series of daily rainfall to hourly intervals. We found that inclusion of the intensity dependency on the model parameters that generate dry intervals greatly improved performance. For the relatively small range of time scales over which the rainfall was disaggregated, varying model parameters with time scale resulted in minor improvement

Comment on ‘‘Capabilities and limitations of tracing spatial temperature patterns by fiber-optic distributed temperature sensing’’ by Liliana Rose et al.

Water ManagementCivil Engineering and Geoscience

The smart climate observation network that covers all Africa

There is a lack of weather and climate observation stations in Africa, while food production, harvest predictions, and disaster mitigation would benefit from improved data-accessible observation. A new smart and sustainable weather and climate observation network now addresses the important challenge of monitoring the weather in the continent.Water Resource

Pore scale consideration in unstable gravity driven finger flow

[2] To explain the dynamic behavior of the matric potential at the wetting front of gravity driven fingers, we take into account the pressure across the interface that is not continuous and depends on the radius of the meniscus, which is a function of pore size and the dynamic contact angle θd. θd depends on a number of factors including velocity of the water and can be found by the Hoffman-Jiang equation that was modified for gravity effects. By assuming that water at the wetting front imbibes one pore at a time, realistic velocities are obtained that can explain the capillary pressures observed in unstable flow experiments in wettable and water repellent sands

Skin effect of fresh water measured using distributed temperature sensing

A phenomenon known as the skin effect-a layer of surface water that is colder than the water beneath it-was previously described in oceanography and verified in lab measurements. Only a few measurements have been done on the skin effect in field conditions, and therefore this phenomenon is relatively unknown. This paper presents measurements of the skin effect for three fresh water bodies in the Netherlands, Israel and Ghana. Using Distributed Temperature Sensing, high temporal and spatial resolution measurements were made below, at and above the air-water surface. Measurements presented in this study suggest that the skin effect of fresh water bodies is predominantly a daytime phenomenon and only occurs during low to zero wind speeds. The thickness of the skin effect was measured to be an order of magnitude larger than the previously assumed less than 1 mm.Water Resource