Trend analysis of evapotranspiration and its response to droughts over India

Madhu, Swati; Kumar, T. V. Lakshmi; Barbosa, Humberto Alves; Rao, K. Koteswara; Bhaskar, V. Vizaya

doi:10.1007/s00704-014-1210-3

Cited by 27 publications

(22 citation statements)

References 18 publications

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“…The results showed that ET 0 and AI decreased as the P increased, especially during drought or wet years and vice versa ( Figure 10). This was consistent with Madhu et al [33], who reported that higher ET values were detected in the moderate and severe droughts years. It could be inferred from Equation (6) that AI has a positive correlation with ET 0 and a negative correlation with P. The correlation was analyzed by the Pearson correlation analysis, and the results showed that AI has a significant positive correlation with ET 0 (r = 0.766, p = 0.00), and it has a significant negative correlation with P (r = −0.977, p = 0.00).…”

Section: Discussionsupporting

confidence: 93%

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Changes of Reference Evapotranspiration and Its Relationship to Dry/Wet Conditions Based on the Aridity Index in the Songnen Grassland, Northeast China

Zhang

Sun

et al. 2017

Water

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Abstract:Reference evapotranspiration (ET 0 ) plays an important role in regional dry/wet conditions. Based on the Food and Agriculture Organization of the United (FAO) Penman-Monteith method and daily climate variables, ET 0 was calculated for 21 stations in and around the Songnen Grassland, northeast China, during 1960China, during -2014. The temporal and spatial variations of ET 0 and precipitation (P) were analyzed in the annual, seasonal, and growing season (from April to October) time series using the Mann-Kendall test, Sen's slope estimator, and linear regression coupled with a break trend analysis. A sensitivity analysis was used to detect the key climate parameter contributing to ET 0 change. By linear regression analysis on the relationship between ET 0 , P, and the aridity index (AI), the role of ET 0 in determining regional wet/dry conditions was analyzed. Results show a higher ET 0 in the southwest and a lower ET 0 in the northeast, but P was opposite to that of ET 0 . Evident decreasing trends of ET 0 in the annual, seasonal, and growing season time series were detected in almost the entire region by the trend analysis methods. For the entire region, the decreasing trend of ET 0 can be linked to the relative humidity and maximum air temperature. The positive contribution of increasing temperature to ET 0 was offset by the effect of the significantly decreasing relative humidity, wind speed, and sunshine duration at the 0.05 level during 1960-2014. In addition, the value of ET 0 was higher in drought years and lower in wet years.

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Section: Discussionsupporting

confidence: 93%

“…Linear regression coupled with break trend analysis [33] was applied to calculate the temporal trends of the ET 0 series for the period from 1960-2014. This method is one of the linear trend methods, which divides a certain time series into several periods.…”

Section: Trend Analysismentioning

confidence: 99%

Changes of Reference Evapotranspiration and Its Relationship to Dry/Wet Conditions Based on the Aridity Index in the Songnen Grassland, Northeast China

Zhang

Sun

et al. 2017

Water

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“…Given the extensive serious impacts of drought, understanding its causes in the past and projecting future drought conditions is an important task in drought studies, and has been well received in the literature. Many recent studies have employed various drought indices and have assessed trends in drought duration or severity (Dubrovský et al, 2014;Park et al, 2014;Yu et al, 2014;Duffy et al, 2015;Madhu et al, 2015;Swain and Hayhoe, 2015), investigated the relationship of drought and climate teleconnections (Kam et al, 2014;Huang et al, 2015;Meque and Abiodun, 2015;Ujeneza and Abiodun, 2015), or evaluated the causes of a particular drought event (Griffin and Anchukaitis, 2014;Diffenbaugh et al, 2015;Mao et al, 2015;Seager et al, 2015;Williams et al, 2015;Otkin et al, 2016). Improvements in accuracy and spatial resolution of datasets as well as greater availability and accessibility to ensembles of models with more realistic physical assumptions, allows for a better assessment of drought attributes in different regions while also characterizing the uncertainty of drought projections (Barnston and Lyon, 2016).…”

Section: Introductionmentioning

confidence: 99%

Centennial drought outlook over the CONUS using NASA‐NEX downscaled climate ensemble

Ahmadalipour

Moradkhani

Svoboda

2016

Intl Journal of Climatology

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Drought is a natural hazard developing slowly and affecting large areas which may have severe consequences on society and economy. Due to the effects of climate change, drought is expected to exacerbate in various regions in future. In this study, the impact of climate change on drought characteristics is assessed, and statistical methods are employed to analyse the significance of projections. This is the first study utilizing 21 recently available downscaled global climate models generated by NASA (NEX‐GDDP) to evaluate drought projections over various regions across the United States. Drought is investigated through a multi‐model dual‐index dual‐scenario approach to probabilistically analyse drought attributes while characterizing the uncertainty in future drought projections. Standardized Precipitation Index and Standardized Precipitation Evapotranspiration Index values at the seasonal scale (3 months) are used to project and analyse meteorological drought conditions from 1950 to 2099 at 0.25° spatial resolution. Two future concentration pathways of RCP4.5 and RCP8.5 are considered for this analysis. Accounting for the combined effects of precipitation and temperature variations reveals a considerable aggravation in severity and extent of future drought in the western United States and a tendency toward more frequent and intense summer droughts across the Contiguous United States.

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“…Terrestrial evapotranspiration (hereafter referred to as ET), which involves transferring water from soil and vegetation into the atmosphere, is closely coupled with the water, energy, and carbon cycles in terrestrial ecosystems. Changes in ET exert critical impacts on regional water cycles, vegetation growth, and the consequent local climate feedback Madhu et al, 2014;Xia et al, 2014], particularly in arid and semiarid regions. Such regions are generally characterized by strong water stress on and clear seasonality in vegetation growth [Mohammat et al, 2013;Wu and Liu, 2013].…”

Section: Introductionmentioning

confidence: 99%

Seasonal divergence in the sensitivity of evapotranspiration to climate and vegetation growth in the Yellow River Basin, China

Pei

et al. 2017

JGR Biogeosciences

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Seasonal variations in terrestrial evapotranspiration (ET) in the Yellow River Basin (YRB) have crucial impacts on the seasonal trajectories of the regional water cycle, vegetation growth, and local climate feedback. However, the possibly divergent roles of climate and vegetation growth variations in controlling seasonal ET patterns remain poorly quantified. This study therefore quantifies the interannual sensitivity and attribution of ET to climate and vegetation growth variations in different seasons and different biomes in the YRB in China between 1982 and 2011, using the satellite‐derived normalized difference vegetation index (NDVI), FLUXNET‐based upscaled ET, and concurrent climate data. The results reveal a clear seasonal divergence in the interannual sensitivity of ET to climate and vegetation growth variations in the YRB. Interannual precipitation and NDVI variations play a dominant role in controlling seasonal ET variations in the YRB, with temperature having a marginal effect. Interannual ET sensitivity to precipitation weakens with an increasing mean annual precipitation gradient in almost all seasons, especially in summer and autumn. More importantly, a seasonally varying role of vegetation growth in mediating seasonal ET was discovered, and a crucial role of late‐growing‐season vegetation growth in controlling the seasonal trajectory of regional ET was explicitly identified. These results suggest that ongoing intensive vegetation restoration has crucial impacts on seasonal water‐cycle patterns and consequent terrestrial‐atmospheric biogeochemical feedback in the YRB.

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Trend analysis of evapotranspiration and its response to droughts over India

Cited by 27 publications

References 18 publications

Changes of Reference Evapotranspiration and Its Relationship to Dry/Wet Conditions Based on the Aridity Index in the Songnen Grassland, Northeast China

Changes of Reference Evapotranspiration and Its Relationship to Dry/Wet Conditions Based on the Aridity Index in the Songnen Grassland, Northeast China

Centennial drought outlook over the CONUS using NASA‐NEX downscaled climate ensemble

Seasonal divergence in the sensitivity of evapotranspiration to climate and vegetation growth in the Yellow River Basin, China

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