Adam Jacob Purdy

Adam Jacob Purdy
University of San Francisco | USFCA · Department of Environmental Science

Ph.D.

About

17
Publications
6,074
Reads
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985
Citations

Publications

Publications (17)
Preprint
Full-text available
Groundwater provides nearly half of irrigation water supply, and it enables resilience during drought, but in many regions of the world, it remains poorly, if at all managed. In heavily agricultural regions like California’s Central Valley, where groundwater management is being slowly implemented over a 27-year period that began in 2015, groundwate...
Article
Land surface models range in complexity of terrestrial evapotranspiration, yet it is unknown how model complexity translates to accuracy of modeled evapotranspiration estimates. Here, we use the International Land Model Benchmarking system to assess ET estimates from three models of varying complexity driven by the same forcing datasets: an earth s...
Article
Full-text available
In-depth knowledge about the global patterns and dynamics of land surface net water flux (NWF) is essential for quantification of depletion and recharge of groundwater resources. Net water flux cannot be directly measured and its estimates as a residual of individual surface flux components often suffer from mass conservation errors due to accumula...
Article
We present a parameter estimation study of the Soil-Tree-Atmosphere Continuum (STAC) model, a process-based model that simulates water flow through an individual tree and its surrounding root zone. Parameters are estimated to optimize the model fit to observations of sap flux, stem water potential, and soil water storage made for a white fir (Abies...
Article
Satellite based retrievals of evapotranspiration (ET) are widely used for assessments of global and regional scale surface fluxes. However, the partitioning of the estimated ET between soil evaporation, transpiration, and canopy interception regularly shows strong divergence between models, and to date, remains largely unvalidated. To examine this...
Article
Full-text available
Accurately estimating evapotranspiration (ET) at large spatial scales is essential to our understanding of land-atmosphere coupling and the surface balance of water and energy. Comparisons between remote sensing-based ET models are difficult due to diversity in model formulation, parametrization and data requirements. The constituent components of...
Article
Full-text available
Accurate and detailed knowledge of California’s groundwater is of paramount importance for statewide water resources planning and management, and to sustain a multi-billion-dollar agriculture industry during prolonged droughts. In this study, we use water supply and demand information from California’s Department of Water Resources to develop an ag...
Article
Uncertainty in ground heat flux (G) means that evaluation of the other terms in the surface energy balance (e.g., latent and sensible heat flux, LE and H) remains problematic. Algorithms that calculate LE and H require available energy, the difference between net radiation, RNET, and G. There are a wide range of approaches to model G for large-scal...
Article
Full-text available
The complexity involved in accurate estimation and numerical simulation of regional evapotranspiration (ET) can lead to inconsistency among techniques, usually attributed to methodological deficiencies. Here we hypothesize instead that discrepancies in ET estimates should be expected in some cases and can be applied to measure the effect of anthrop...
Article
In California and other regions vulnerable to water shortages, satellite-derived estimates of key hydrologic fluxes can support agricultural producers and water managers in maximizing the benefits of available water supplies. The Satellite Irrigation Management Support (SIMS) project combines NASA's Terrestrial Observation and Prediction System (TO...
Article
Satellite data can be used to map crop evapotranspiration over large areas and make irrigation scheduling more practical, convenient, and accurate, but requires the development of new tools and computing frameworks to support operational use in irrigation scheduling and water management. We present findings from the development and deployment of a...
Poster
Irrigation scheduling systems can potentially be improved through the combined use of satellite driven estimates of crop evapotranspiration and real-time soil moisture data from wireless sensor networks. In order to analyze spatial and temporal patterns in soil moisture and evapotranspiration, we used wireless sensor networks deployed in operationa...

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