Thermocouple frequency response compensation leads to convergence of the surface renewal alpha calibration

Shapland, T. M.; Snyder, Richard L.; McElrone, Andrew J.

doi:10.1016/j.agrformet.2014.01.008

Cited by 35 publications

(22 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Responses to the spatial and temporal shifts in water quantity and quality due to climate change involve many scales and stakeholders, and the need for coordinated planning at regional and national scales will increase with growth in the urban and industrial sectors. Approaches to increasing the efficiency of water used for food supply must employ drought-tolerant crops and irrigation technology (for example, water-conserving irrigation systems, crop coefficients and surface renewal [250,251]). They also need to address both consumptive behaviour (that is, overconsumption and resourceintensive food selection) and waste incurred during postharvest and along the supply chain (for example, threshing, transport, storage) [252].…”

Section: Water Management For Food and Fishery Systemsmentioning

confidence: 99%

Climate-smart agriculture global research agenda: scientific basis for action

et al. 2014

View full text Add to dashboard Cite

Background: Climate-smart agriculture (CSA) addresses the challenge of meeting the growing demand for food, fibre and fuel, despite the changing climate and fewer opportunities for agricultural expansion on additional lands. CSA focuses on contributing to economic development, poverty reduction and food security; maintaining and enhancing the productivity and resilience of natural and agricultural ecosystem functions, thus building natural capital; and reducing trade-offs involved in meeting these goals. Current gaps in knowledge, work within CSA, and agendas for interdisciplinary research and science-based actions identified at the 2013 Global Science Conference on Climate-Smart Agriculture (Davis, CA, USA) are described here within three themes: (1) farm and food systems, (2) landscape and regional issues and (3) institutional and policy aspects. The first two themes comprise crop physiology and genetics, mitigation and adaptation for livestock and agriculture, barriers to adoption of CSA practices, climate risk management and energy and biofuels (theme 1); and modelling adaptation and uncertainty, achieving multifunctionality, food and fishery systems, forest biodiversity and ecosystem services, rural migration from climate change and metrics (theme 2). Theme 3 comprises designing research that bridges disciplines, integrating stakeholder input to directly link science, action and governance.

show abstract

Section: Water Management For Food and Fishery Systemsmentioning

confidence: 99%

Climate-smart agriculture global research agenda: scientific basis for action

et al. 2014

View full text Add to dashboard Cite

show abstract

“…Accurate estimation and mapping of crop ET across space and time are essential for improving field-scale irrigation management and for watershed and regional water planning and management. Ground-based flux measurement methods such as eddy covariance (EC) [2], Bowen ratio (BR) [3], and most recently surface renewal (SR) [4], can provide half-hourly, hourly, and daily ET measurements and thus offer guidance to growers for time sensitive irrigation scheduling. However, these measurements are limited by the small scale of the footprint area of the measurement stations and they cannot capture heterogeneity within each agriculture field, and sometimes cannot represent the entire field or orchard conditions.…”

Section: Introductionmentioning

confidence: 99%

Evapotranspiration Estimate over an Almond Orchard Using Landsat Satellite Observations

Jin

Kandelous

et al. 2017

Remote Sensing

View full text Add to dashboard Cite

California growers face challenges with water shortages and there is a strong need to use the least amount of water while optimizing yield. Timely information on evapotranspiration (ET), a dominant component of crop consumptive water use, is critical for growers to tailor irrigation management based on in-field spatial variability and in-season variations. We evaluated the performance of a remote sensing-based approach, Mapping Evapotranspiration at high Resolution with Internalized Calibration (METRIC), in mapping ET over an almond orchard in California, driven by Landsat satellite observations. Reference ET from a network of weather stations over well-watered grass (ET o ) was used for the internal calibration and for deriving ET at daily and extended time period, instead of alfalfa based reference evapotranspiration (ET r ). Our study showed that METRIC daily ET estimates during Landsat overpass dates agreed well with the field measurements. During 2009-2012, a root mean square error (RMSE) of 0.53 mm/day and a coefficient of determination (R 2 ) of 0.87 were found between METRIC versus observed daily ET. Monthly ET estimates had a higher accuracy, with a RMSE of 12.08 mm/month, a R 2 of 0.90, and a relatively small relative mean difference (RMD) of 9.68% during 2009-2012 growing seasons. Net radiation and Normalized Difference Vegetation Index (NDVI) from remote sensing observations were highly correlated with spatial and temporal ET estimates. An empirical model was developed to estimate daily ET using NDVI, net radiation (R n ), and vapor pressure deficit (VPD). The validation showed that the accuracy of this easy-to-use empirical method was slightly lower than that of METRIC but still reasonable, with a RMSE of 0.71 mm/day when compared to ground measurements. The remote sensing based ET estimate will support a variety of State and local interests in water use and irrigation management, for both planning and regulatory/compliance purposes, and it provides the farmers observation-based guidance for site-specific and time-sensitive irrigation management.

show abstract

“…In applied research, custom algorithms are often developed by individual researchers, requiring special training in programming, significant time investment, and the motivation to use sophisticated techniques that fully utilize 210 available memory and processing power. Efforts to standardize the eddy covariance method Baldocchi, 2014) and data quality control (Allen et al, 2011;Foken et al, 2012) have not yet been similarly applied to the SR method, although substantial work has been made to validate calibration and field methods (Castellví, 2012;Paw U et al, 2005b;Shapland et al, 2014). By appropriating methods common in signal processing and computer science, and by sharing open source tools using online forums such as stackexchange.com, more 215 sophisticated approaches can be implemented.…”

Section: Discussionmentioning

confidence: 99%

“…(Van Atta, 1977) suggested that ramp time τ should be related linearly to amplitude A, and proposed: In practice, determination of ramp time τ from A using this equation requires an empirical calibration; this calibration has been shown to be related to surface conditions and instrumentation (Chen et al, 1997b). Ongoing work using replicate measurements at multiple heights (Castellvi, 2004) and frequency response calibration 200 (Shapland et al, 2014) have begun to resolve the causes of variability in this parameter. In this study, it was found that the ratio in equation 4 remains essentially constant for a given surface roughness condition, allowing determination of τ algebraically.…”

Section: Cardano's Methods For Depressed Cubic Polynomialsmentioning

confidence: 99%

Computational Efficiency for the Surface Renewal Method

Kelley¹,

Higgins²

2017

Preprint

View full text Add to dashboard Cite

Abstract. Measuring surface fluxes using the surface renewal (SR) method requires a set of programmatic algorithms for tabulation, algebraic calculation, and quality control. Field experiments were conducted over a variety of surface conditions to determine the shortest valid time averaging period for the SR method. Because the SR method utilizes high frequency (20 Hz+) measurements, some steps in the flux calculation are computationally expensive, especially when automating SR to perform many iterations of these calculations. For a study on the 10 minimum time to measure flux, several new algorithms were written to perform the required calculations more efficiently and rapidly. These algorithms demonstrate that simple modifications to SR methods can dramatically improve efficiency. Such programming techniques grant a degree of flexibility to the method, opening new avenues for SR to be used in research, for applied monitoring, and in novel field deployments.

show abstract

Thermocouple frequency response compensation leads to convergence of the surface renewal alpha calibration

Cited by 35 publications

References 28 publications

Climate-smart agriculture global research agenda: scientific basis for action

Climate-smart agriculture global research agenda: scientific basis for action

Evapotranspiration Estimate over an Almond Orchard Using Landsat Satellite Observations

Computational Efficiency for the Surface Renewal Method

Contact Info

Product

Resources

About