EVAPOTRANSPIRATION
fully coupled atmosphere-ocean-land models that use mathematical representations of the laws of physics to simulate the movement of heat, momentum and water fluxes between grid cells.
Although a step forward for ET-based irrigation management, FRET is a mean forecast for a grid cell, not for a specific location within a grid cell, such as a vineyard block or field (see fig. 4).
To the extent that a field does not represent the mean location within a grid cell, forecast error increases. Recent advances in machine learning, however, offer a potential path forward for improving weather and ETO forecast accuracy at the field scale.
Dynamical models are based on fundamental physics, but they also incorporate hundreds of semi-empirical relationships to approximate processes, such as cloud formation, that are too fine for the models to resolve. These relationships are ill-constrained and represent a major source of uncertainty and model error.
Machine learning may be able to circumvent this long-standing problem in several ways. First, machine learning algorithms may be able to better represent the fundamentals of sub- grid weather processes and thus used to supplement dynamical models. A second, more radical possibility is that machine learning techniques might improve the accuracy of weather forecasts while abandoning the scaffolding of traditional dynamical models altogether.
Considering these advances, along with the decreasing costs of connected weather instrumentation and the proliferation of farm management information systems, the future of ET-based irrigation management looks bright. Having these tools made available to growers for use in managing irrigation effectively not only benefits the irrigation industry but also takes steps to help insure its role in future sustainability.
Christopher Lund is co-founder and CEO of Benchmark Labs.
Considering these advances … the future of ET-based irrigation
management looks bright.
Performs well under pressure.
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irrigationtoday.org Winter 2020 | Irrigation TODAY 25
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