Pan Evaporation to Reference Evapotranspiration Conversion Methods

Grismer, Mark E.; Orang, M.; Snyder, Richard L.; Matyac, R.

doi:10.1061/(asce)0733-9437(2002)128:3(180)

Cited by 119 publications

(64 citation statements)

References 4 publications

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“…Therefore, the ground flux is not included in subsequent analyses, which are instead based on the standard ETo estimates reported by CIMIS. CIMIS ETo estimates and nearby pan evaporation station data (E pan ) are well correlated at monthly scales (Table 1; see also Grismer et al 2002). However, the E pan rates are usually higher than their corresponding ETo estimates.…”

Section: Data a Meteorological Recordsmentioning

confidence: 72%

Sources of Variability of Evapotranspiration in California

Hidalgo

Cayan

Dettinger

2005

Journal of Hydrometeorology

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The variability (1990)(1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002) of potential evapotranspiration estimates (ETo) and related meteorological variables from a set of stations from the California Irrigation Management System (CIMIS) is studied. Data from the National Climatic Data Center (NCDC) and from the Department of Energy from 1950 to 2001 were used to validate the results. The objective is to determine the characteristics of climatological ETo and to identify factors controlling its variability (including associated atmospheric circulations). Daily ETo anomalies are strongly correlated with net radiation (R n ) anomalies, relative humidity (RH), and cloud cover, and less with average daily temperature (T avg ). The highest intraseasonal variability of ETo daily anomalies occurs during the spring, mainly caused by anomalies below the high ETo seasonal values during cloudy days. A characteristic circulation pattern is associated with anomalies of ETo and its driving meteorological inputs, R n , RH, and T avg , at daily to seasonal time scales. This circulation pattern is dominated by 700-hPa geopotential height (Z 700 ) anomalies over a region off the west coast of North America, approximately between 32Њ and 44Њ latitude, referred to as the California Pressure Anomaly (CPA). High cloudiness and lower than normal ETo are associated with the lowheight (pressure) phase of the CPA pattern. Higher than normal ETo anomalies are associated with clear skies maintained through anomalously high Z 700 anomalies offshore of the North American coast. Spring CPA, cloudiness, maximum temperature (T max ), pan evaporation (E pan ), and ETo conditions have not trended significantly or consistently during the second half of the twentieth century in California. Because it is not known how cloud cover and humidity will respond to climate change, the response of ETo in California to increased greenhousegas concentrations is essentially unknown; however, to retain the levels of ETo in the current climate, a decline of R n by about 6% would be required to compensate for a warming of ϩ3ЊC.

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Section: Data a Meteorological Recordsmentioning

confidence: 72%

Sources of Variability of Evapotranspiration in California

Hidalgo

Cayan

Dettinger

2005

Journal of Hydrometeorology

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“…According GRISMER et al (2002), there are approximately, fifty methods for estimate ET0, which require distinct meteorological information, and therefore often produce inconsistent results. The Penman-Monteith method (ALLEN et al, 1998) has been recommended by the FAO as standard to calculate the ET0 and has been used worldwide.…”

Section: Introductionmentioning

confidence: 99%

Performance of Estimative Models for Daily Reference Evapotranspiration in the City of Cassilândia, Brazil

et al. 2017

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“…One of the simpler techniques is to directly measure the water evaporation in the field from an evaporation pan, which is an apparently simple integrated measurement of complex meteorological interactions, such as solar radiation, temperature, humidity, and wind speed. Although pan evaporation cannot fully represent lake evaporation, it has been found as proportional to actual evaporation of moist surfaces, such as lakes or irrigated fields (Kahler and Brutsaert 2006), and also calculated reference crop evapotranspiration (Brouwer and Heibloem 1986;Grismer et al 2002;Snyder et al 2005;Ertek et al 2006). Because pans of various designs have produced data for many regions throughout the world for long periods, attempts have also been made to use these data to estimate actual evaporation even in non-moist environments.…”

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confidence: 99%

A critical overview of pan evaporation trends over the last 50 years

Charles

2009

Climatic Change

122

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Despite the observed increases in global average temperature, observations across the world show that the rate of pan evaporation at a regional scale has been steadily decreasing over the past 50 years. This is known as the pan evaporation paradox. This paper reviews current reported pan evaporation trends, examines available theoretical explanations about this "paradox", and discusses current research gaps and priorities. It concludes that: (1) three major potential causes of pan evaporation, solar radiation, vapour pressure deficit (VPD) and wind speed, have been changing in the last 50 years. The magnitude of changes and importance of each of these three causes varies from region to region, as does the pan evaporation trend, although overall there is a decreasing trend. (2) Currently two existing theories explaining the pan evaporation trends have limits and are only valid in some specific regions and seasons. Neither of them provides a fundamental physical-based theory that could be applied everywhere. (3) Further investigations are needed before we can fully understand the global evapotranspiration trend in global warming scenarios.

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Pan Evaporation to Reference Evapotranspiration Conversion Methods

Cited by 119 publications

References 4 publications

Sources of Variability of Evapotranspiration in California

Sources of Variability of Evapotranspiration in California

Performance of Estimative Models for Daily Reference Evapotranspiration in the City of Cassilândia, Brazil

A critical overview of pan evaporation trends over the last 50 years

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