Evapotranspiration Trends Over the Eastern United States During the 20th Century

Kramer, Ryan J.; Bounoua, Lahouari; Zhang, Ping; Wolfe, Robert E.; Huntington, Thomas G.; Imhoff, Marc L.; Thome, Kurtis J.; Noyce, Genevieve L.

doi:10.3390/hydrology2020093

Cited by 34 publications

(37 citation statements)

References 53 publications

(74 reference statements)

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“…20 According to this study the effect of increased vegetation activity on E 0v is of a similar magnitude as the effect of changes in the atmospheric conditions. A strong influence of changes in vegetation activity on E was also suggested for the eastern US based on correlations between NDVI and E wb (Kramer et al, 2015). Using simulations from a coupled biosphere-atmosphere model, Bounoua et al (2000) found an E increase of 43 mm y −1…”

Section: Drivers Of the Observed Changes In Catchment Evapotranspirationmentioning

confidence: 99%

“…Those 30 studies that exist generally found increases in E wb in the 20 th century. Examples include large river basins in the US (Milly and Dunne, 2001;Walter et al, 2004;Kramer et al, 2015), the Tibetan Plateau (Zhang et al, 2007), and catchments in Switzerland (Spreafico et al, 2007). A study of 109 basins around the world for the period 1961-1999 found only few significant trends but a tendency towards positive trends in North and South America and Europe and a tendency towards negative trends in Africa and Siberia (Ukkola and Prentice, 2013).…”

Section: Introductionmentioning

confidence: 99%

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Why has catchment evaporation increased in the past 40 years? A data-based study in Austria

Duethmann¹,

Blöschl²

2018

Preprint

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Abstract. Global warming has increased regional evapotranspiration in many parts of the world in the last decades, but the drivers of these increases are widely debated. Part of the difficulty lies in the scarcity of high-quality long term data on evapotranspiration.In this paper, we analyze changes in catchment evapotranspiration estimated from the water balances of 156 catchments in Austria over the period 1977-2014 and attribute them to changes in atmospheric demand and available 10 energy, vegetation, and soil moisture as possible drivers. Trend analyses suggest that evapotranspiration has significantly increased in 60 % of the catchments (p≤0.05) with an average increase of 29 ± 14 mm y . Estimates of reference evaporation accounting for changes in stomata resistance due to changes in NDVI indicate that the increase in vegetation activity has led to a similar increase in reference evaporation as changes in the climate parameters. A regression between trends in evapotranspiration and precipitation, as a proxy of soil moisture, yields a sensitivity of 0.30 ± 0.04 mm y −2 increase in evapotranspiration to 1 mm y −2 20 increase in precipitation. A synthesis of the data analyses suggests that 38 ± 13 % of the observed increase in catchment evapotranspiration can be directly attributed to increased atmospheric demand and available energy, 30 ± 12 % to increased vegetation activity, and 32 ± 5 % to increased soil moisture due to increases in precipitation. IntroductionEvapotranspiration (E) is an important process in the water, energy, and carbon cycles and directly controls agricultural 25 productivity and water availability for human purposes. Global warming has increased regional E in many parts of the world in the last decades (Huntington, 2006). However, due to the difficulty of measuring E, especially at large spatial scales, the drivers of changing E are still debated.Decadal changes in catchment E may be inferred from the catchment water balance, as storage changes are usually small over decadal scales. Surprisingly few studies have investigated trends in water balance based evapotranspiration (E wb , despite increases in air temperature (Peterson et al., 1995;Roderick et al., 2009;McVicar et al., 2012). In some instances, this decrease in E pan has been explained by decreases in net radiation and/or wind speed (Roderick and Farquhar, 20 2002;Roderick et al., 2007). In other instances, decreasing E pan has been interpreted as a consequence of increasing actual evaporation (Brutsaert and Parlange, 1998;Brutsaert, 2013). In Europe, most studies found increasing trends of E pan (e.g. Ireland (1963Ireland ( -2005 (Stanhill and Möller, 2008), England (1957-2004 and 1986 (Stanhill and Möller, 2008;Clark, 2013), Greece (1983Greece ( -1999 (Papaioannou et al., 2011), and the Czech Republic (Trnka et al., 2015)). In this paper, we use the term atmospheric conditions to summarize the drivers available energy and atmospheric demand. 3 CO 2 concentration and nitrogen deposition, Mao et al. (2015) found that...

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Section: Drivers Of the Observed Changes In Catchment Evapotranspirationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Why has catchment evaporation increased in the past 40 years? A data-based study in Austria

Duethmann¹,

Blöschl²

2018

Preprint

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“…Similarly, groundwater storage changes are not accounted for in the water balance. Trends in groundwater levels are difficult to quantify, and the evidence is mixed in the study region (Brutsaert, ; Dudley & Hodgkins, ; Kramer et al, ; Shanley, Chalmers, Mack, Smith, & Harte, ), but on balance groundwater levels appear to be lowering over the time period we examined. Nonetheless, the effects of the exclusion of groundwater estimates on the results of any water balance analysis deserve consideration (Sharma & Walter, ).…”

Section: Discussionmentioning

confidence: 92%

“…At a smaller spatial scale in eastern Pennsylvania, a 44‐year analysis of a single 7‐km 2 mixed agricultural‐forest watershed also showed a strong increasing AET trend (Lu et al, ), which was attributed mostly to increased temperatures and a longer growing season. Kramer et al () found an increase in AET across most eastern U.S. hydrologic regions, which they attributed in part to increased transpiration during longer growing seasons. Some models and global‐scale studies have predicted declines in AET, or smaller gains than would be expected from climate drivers alone, associated with increased water use efficiency as stomatal conductance is reduced in response to increasing atmospheric CO 2 concentrations (Mao et al, ; Milly & Dunne, ; Szilagyi et al, ).…”

Section: Discussionmentioning

confidence: 99%

Systematic variation in evapotranspiration trends and drivers across the Northeastern United States

Vadeboncoeur

Green

Asbjornsen

et al. 2018

Hydrological Processes

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The direction and magnitude of responses of evapotranspiration (ET) to climate change are important to understand, as ET represents a major water and energy flux from terrestrial ecosystems, with consequences that feed back to the climate system. We inferred multidecadal trends in water balance in 11 river basins (1940–2012) and eight smaller watersheds (with records ranging from 18 to 61 years in length) in the Northeastern United States. Trends in river basin actual ET (AET) varied across the region, with an apparent latitudinal pattern: AET increased in the cooler northern part of the region (Maine) but decreased in some warmer regions to the southwest (Pennsylvania–Ohio). Of the four small watersheds with records longer than 45 years, two fit this geographic pattern in AET trends. The differential effects of the warming climate on AET across the region may indicate different mechanisms of change in more‐ vs. less‐energy‐limited watersheds, even though annual precipitation greatly exceeds potential ET across the entire region. Correlations between AET and time series of temperature and precipitation also indicate differences in limiting factors for AET across the Northeastern U.S. climate gradient. At many sites across the climate gradient, water‐year AET correlated with summer precipitation, implying that water limitation is at least transiently important in some years, whereas correlations with temperature indices were more prominent in northern than southern sites within the region.

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“…Kramer ve ark. [10], Amerika'nın doğusunda 20. yüzyıl boyunca evapotranspirasyon için artış trendi belirlemişlerdir. Saplıoğlu [11], iklim değişimi araştırmalarında kullanılan trend analizi için yeni bir yöntem geliştirmiş ve geliştirdiği yöntemi Isparta ve Burdur illerinin yağış verilerine uygulamıştır.…”

Section: Introductionunclassified

Ni̇ğde İli̇’ndeki̇ Potansi̇yel Evapotranspi̇rasyon Tahmi̇nleri̇ni̇n Trend Anali̇zi̇

Arslan¹

2017

Ömer Halisdemir Üniversitesi Mühendislik Bilimleri Dergisi

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ÖZİklim değişiminin incelenmesi su kaynaklarının planlanması ve yönetimi açısından büyük önem taşımaktadır ve potansiyel evapotranspirasyon iklim değişiminin incelenmesi için önemli bir parametredir. Bu çalışmada, Niğde İli'nin potansiyel evapotranspirasyon değerleri Turc ve Coutagne formülleri kullanılarak hesaplanmıştır ve hesaplanan değerler için trend analizi gerçekleştirilmiştir. Niğde İli'nin 1950 ve 2015 arasındaki yıllık toplam yağış ve yıllık ortalama sıcaklık değerleri potansiyel evapotranspirasyon değerlerinin hesaplanması için kullanılmıştır. Verilerin homojenliğinin araştırılması için run testi uygulanmıştır. Trend analizi için Mann Kendall Mertebe Korelasyon (MKMK) testi kullanılmıştır. Run testi sonuçları verilerin %95 güven aralığında homojen olduğunu göstermiştir. Her iki yöntemden elde edilen potansiyel evapotranspirasyon değerlerine uygulanan trend analizi sonuçlarına göre trendler istatistiksel olarak anlamlı değildir. Ancak, bir artış trendi gözlenmiştir. Bu durum Niğde'de bulunan barajların yönetimini etkileyebilir.Anahtar Kelimeler: Mann Kendall mertebe korelasyon, Turc, Coutagne, evapotranspirasyon, Niğde TREND ANALYSIS OF POTENTIAL EVAPOTRANSPIRATION PREDICTIONS IN NIGDE PROVINCE ABSTRACTInvestigation of climate change is of great importance for the planning and management of water resources and potential evapotranspiration is an important parameter for investigation of climate change. In this study, potential evapotranspiration values of Nigde province was calculated by using Turc and Coutagne formulas and a trend analysis was performed for calculated values. Yearly total precipitation and yearly mean temperature values of Nigde province between 1950 and 2015 were used for calculating potential evapotranspiration values. Run test is applied for investigation of homogeneity of data. Mann Kendall Rank Correlation (MKRC) test was used for trend analysis. Run test results indicated that the data were homogeny at the 95% confidence interval. According to the results of trend analysis applied to potential evapotranspiration values obtained from both of two methods, the trends were not statistically significant. However, an increasing trend was observed. This can affect the management of dams in Nigde.

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Evapotranspiration Trends Over the Eastern United States During the 20th Century

Cited by 34 publications

References 53 publications

Why has catchment evaporation increased in the past 40 years? A data-based study in Austria

Why has catchment evaporation increased in the past 40 years? A data-based study in Austria

Systematic variation in evapotranspiration trends and drivers across the Northeastern United States

Ni̇ğde İli̇’ndeki̇ Potansi̇yel Evapotranspi̇rasyon Tahmi̇nleri̇ni̇n Trend Anali̇zi̇

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