Spatial simulation of evapotranspiration of semi-arid Inner Mongolian grassland based on MODIS and eddy covariance data

Vetter, Sylvia H.; Schaffrath, David; Bernhofer, Christian

doi:10.1007/s12665-011-1187-5

Cited by 22 publications

(21 citation statements)

References 31 publications

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“…Despite the above uncertainties, this study confirmed the spatiotemporal variations in ET 0 and also indicated the dominant factors in the two time series as reported in many previous studies Liu et al 2011b;Zhang et al 2013). Furthermore, we also recommend that more attention should be paid to actual evapotranspiration (ET a ) (Vetter et al 2012), especially in response to climate change and human activities. For example, we can acquire the spatiotemporal ET a for a particular region or basin with ET a products (Cai et al 2014;Li et al 2014b;Xue et al 2013), or construct better ET a model for our own study area with more precise forcing datasets (Minderlein and Menzel 2015;Yin et al 2013;Zhang et al 2008b).…”

Section: Climate Factors Trendsupporting

confidence: 88%

The spatiotemporal variation of reference evapotranspiration and the contribution of its climatic factors in the Loess Plateau, China

Liang

Bai

et al. 2016

Environ Earth Sci

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Reference evapotranspiration (ET 0 ) is an important parameter of agricultural activity and hydrometeorological studies. In this study, we used the Food and Agriculture Organization Penman-Monteith equation to evaluate ET 0 , and to investigate the change point of ET 0 in the Loess Plateau region from 1960 to 2013. The results showed that a change point was detected at approximately the year 1990 for annual ET 0 series from 108 meteorological stations using Cramer's statistical test. The annual ET 0 decreased significantly (p \ 0.05) by -1.22 mm year -1 from 1960 to 1990, especially during the summer months, which contributed the most to the total annual reduction, while it increased significantly (p \ 0.001) by 1.15 mm year -1 from 1991 to 2013, with the spring months contributing the most. The ET 0 and its trend in the five integrated management divisions of the Loess Plateau have significant spatial heterogeneity. The highest and lowest ET 0 were found in the third and fifth divisions from 1960 to 2013. The ET 0 decreased significantly in the first division and increased in the fourth divisions (1960-1990 and 1991-2013, respectively). Using differential equations to quantitatively evaluate the contribution of various factors, the wind speed was mostly responsible for the variability in the ET 0 trend from 1960 to 1990, followed by solar radiation and vapor pressure. The positive effect of air temperature on ET 0 trend was offset by the other three factors, and the combined effects of the four climatic variables led to the decrease in the ET 0 trend. However, the rapidly increasing air temperature became the predominant factor in the change in the ET 0 trend after 1990. A spatiotemporal variation of predominant contribution to the ET 0 trend was identified. The temperature dominant region changed from the third to the first division for 1960-1990 and 1991-2013. Radiation did not change. Vapor pressure changed from the first to the fourth and the wind speed changed from the forth to the third. This study could contribute to a better understanding of the response of the spatial and temporal variation of ET 0 to increased climate change. Additionally, this research also provides scientific support to regional planning and management.

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Section: Climate Factors Trendsupporting

confidence: 88%

The spatiotemporal variation of reference evapotranspiration and the contribution of its climatic factors in the Loess Plateau, China

Liang

Bai

et al. 2016

Environ Earth Sci

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“…Fan et al, 2007) and process-based land surface models (e.g. Vetter et al, 2012). These procedures often demand far-reaching assumptions, such as the closure of the energy and water balances (e.g.…”

Section: Introductionmentioning

confidence: 99%

Spatially explicit regionalization of airborne flux measurements using environmental response functions

et al. 2013

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Abstract. The goal of this study is to characterize the sensible (H) and latent (LE) heat exchange for different land covers in the heterogeneous steppe landscape of the Xilin River catchment, Inner Mongolia, China. Eddy-covariance flux measurements at 50–100 m above ground were conducted in July 2009 using a weight-shift microlight aircraft. Wavelet decomposition of the turbulence data enables a spatial discretization of 90 m of the flux measurements. For a total of 8446 flux observations during 12 flights, MODIS land surface temperature (LST) and enhanced vegetation index (EVI) in each flux footprint are determined. Boosted regression trees are then used to infer an environmental response function (ERF) between all flux observations (H, LE) and biophysical (LST, EVI) and meteorological drivers. Numerical tests show that ERF predictions covering the entire Xilin River catchment (&approx;3670 km2) are accurate to ≤18% (1 σ). The predictions are then summarized for each land cover type, providing individual estimates of source strength (36 W m−2 < H < 364 W m−2, 46 W m−2 < LE < 425 W m−2) and spatial variability (11 W m−2 < σH < 169 W m−2, 14 W m−2 < σLE < 152 W m−2) to a precision of ≤5%. Lastly, ERF predictions of land cover specific Bowen ratios are compared between subsequent flights at different locations in the Xilin River catchment. Agreement of the land cover specific Bowen ratios to within 12 &pm; 9% emphasizes the robustness of the presented approach. This study indicates the potential of ERFs for (i) extending airborne flux measurements to the catchment scale, (ii) assessing the spatial representativeness of long-term tower flux measurements, and (iii) designing, constraining and evaluating flux algorithms for remote sensing and numerical modelling applications.

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“…One of the focus region is Central Asia (Mongolia and Inner Mongolia), where project partners are focussing among others on environmental simulation (Vetter et al 2011), socio-economical aspects (Sigel et al 2011) and IWRM implementation (Horlemann and Dombrowsky 2011).…”

Section: Introductionmentioning

confidence: 99%

Suspended sediments in the Kharaa River catchment (Mongolia) and its impact on hyporheic zone functions

et al. 2011

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A previous study investigating the ecological status of the Kharaa River in Northern Mongolia reported fine-grained sediments as being a major stress factor causing adverse impacts on the benthic ecology. However, the source of these sediments within the catchment as well as the specific impact on hyporheic zone functions in the Kharaa River remained unclear. Therefore, the objective of the current study was to investigate the underlying sourcereceptor system and implement an integrated monitoring approach. Suspended sediment sources within the Kharaa catchment were identified by using extensive spatially distributed sediment sampling and geochemical and isotope fingerprinting methods. On the receptor side, the ecological implications across a gradient of fine-grained sediment influx were analyzed using a distinct hyporheic zone monitoring scheme at three representative river reaches along the Kharaa River. Results of suspended sediment source monitoring show that during snowmelt runoff, riverbank and gully erosion were the dominant sources. During the summer period, upland erosion contributed a substantial share of suspended sediment. Finegrained sediment influx proved to be the cause of habitat loss in the hyporheic zone and benthic oxygen production limitation. This combined catchment and in-stream monitoring approach will allow for a better understanding and spatially explicit analysis of the interactions of suspended sediment transport and hyporheic zone functioning. This information has built the basis for a coupled modeling framework that will help to develop efficient management measures within the Kharaa River basin with special emphasis on rapidly changing land-use and climatic conditions.

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Spatial simulation of evapotranspiration of semi-arid Inner Mongolian grassland based on MODIS and eddy covariance data

Cited by 22 publications

References 31 publications

The spatiotemporal variation of reference evapotranspiration and the contribution of its climatic factors in the Loess Plateau, China

The spatiotemporal variation of reference evapotranspiration and the contribution of its climatic factors in the Loess Plateau, China

Spatially explicit regionalization of airborne flux measurements using environmental response functions

Suspended sediments in the Kharaa River catchment (Mongolia) and its impact on hyporheic zone functions

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