Multilevel modeling of NPP change and impacts of water resources in the Lower Heihe River Basin

Yan, Haiming; Zhan, Jinyan; Jiang, Qimeng; Yuan, Yanbin; Li, Zhihui

doi:10.1016/j.pce.2014.12.001

Cited by 22 publications

(9 citation statements)

References 62 publications

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“…There have been a number of studies on biomass accumulation in the Heihe River Basin [31,56,74,77], and the biomass accumulation from the C-Fix model agreed well with that in these studies (Figure 2). For example, the mean annual biomass accumulation the whole study area from the C-Fix model (22.08 gC¨m´2¨a´1) was very close to results of Wei et al (23.51 gC¨m´2¨a´1) [77].…”

Section: Model Validationsupporting

confidence: 74%

“…Besides, There have been a number of models for estimating NPP in large areas, which can be categorized into statistical (climate-related) models, light use efficiency (LUE) models and process-based models [28,29]. Among all these models, LUE models have the highest potential to accurately reflect the spatiotemporal dynamics of NPP due to the simplicity of their concepts and the high availability of remote sensing data [11], and various LUE models have been developed (e.g., CASA, C-Fix) [30,31]. In addition, the effects climate change and LUCC on biomass accumulation have been generally analyzed with statistical methods or scenario analysis [32][33][34].…”

Section: Introductionmentioning

confidence: 99%

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Effects of Climate Change and LUCC on Terrestrial Biomass in the Lower Heihe River Basin during 2001–2010

Yan

Zhan

et al. 2016

Energies

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Ecosystem services are tightly coupled with availability of solar energy and its partition into energy fluxes, and biomass accumulation, which represents the energy flux in ecosystems, is a key aspect of ecosystem services. This study analyzed the effects of climate change and land use and land cover change (LUCC) on the biomass accumulation change in the Lower Heihe River Basin during 2001-2010. Biomass accumulation was represented with net primary productivity (NPP), which was estimated with the C-Fix model, and scenario analysis was carried out to investigate effects of climate change and LUCC on biomass accumulation change in a spatially explicit way. Results suggested climate change had an overall positive effect on biomass accumulation, mainly owning to changes in CO 2 concentration and temperature. LUCC accounted for 70.61% of biomass accumulation change, but primarily owning to fractional vegetation change (FVCC) rather than land conversion, and there is a negative interactive effect of FVCC and climate change on biomass accumulation, indicating FVCC resulting from water diversion played a dominant in influencing biomass accumulation. These results can provide valuable decision support information for the local ecosystem managers and decision makers to guarantee sustainable provision of essential ecosystem services.

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Section: Model Validationsupporting

confidence: 74%

Section: Introductionmentioning

confidence: 99%

Effects of Climate Change and LUCC on Terrestrial Biomass in the Lower Heihe River Basin during 2001–2010

Yan

Zhan

et al. 2016

Energies

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“…Water and heat are the major natural resources in terrestrial ecosystems [1][2][3], and their interactions are highly relevant to net primary productivity [4][5][6]. A clear understanding of the characteristics of the land-atmosphere exchange of water and heat in ecosystems forms the scientific basis for the rational development and utilization of natural resources [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Land–Atmosphere Exchange of Water and Heat in the Arid Mountainous Grasslands of Central Asia during the Growing Season

Huang

Luo

Wang

2017

Water

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Arid grassland ecosystems are widely distributed across Central Asia. However, there is a lack of research and observations of the land-atmosphere exchange of water and heat in the arid grasslands in this region, particularly over complex surfaces. In this study, systematic observations were conducted from 2013 to 2015 using an HL20 Bowen ratio and TDR300 and WatchDog1400 systems to determine the characteristics of these processes during the growing season (April-October) of the arid mountainous grasslands of this region. (1) The latent heat flux (Le) was lower than the sensible heat flux (He) overall, and a small transient decrease in Le was observed before its daytime maximum; daily comparative variations in both fluxes were closely related to vegetation growth. (2) Evapotranspiration (ET) showed substantial variation across different years, seasons and months, and monthly variations in ET were closely related to vegetation growth. Water condensation (Q) was low and relatively stable. Relatively high levels of soil water were measured in spring followed by a decreasing trend. The land-atmosphere exchange of water and heat during the growing season in this region was closely associated with phenology, available precipitation and terrain. This study provides data support for the scientific management of arid mountainous grasslands.

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“…In this study, the wind erosion amount and RET were first estimated at the subdaily scale and then summarized at the daily, monthly, and annual scales.

italicSL = \iint_{D} \int_{t_{0}}^{t_{1}} 3.91 \times ((), 1.0413 + 0.0441 \times θ + 0.0021 \times θ^{2} - 0.0001 \times θ^{3}) \times \frac{(V^{2} \times {((), 8.2 \times 10^{- 5})}^{italicFVC} \times {italicSDR}^{2})}{(H^{8} \times d^{2} \times F)} italicdt,

where SL is the soil loss, including the potential and actual soil loss in the landscape without and with vegetation cover, respectively; V is the wind speed, H is the relative air humidity; SDR is the artificial surface destruction rate; d is the average soil particle radius, and the d value of the water body was set to 0.008942 after repeated tests in this study because the soil texture data of the water body were lacking; F is the soil hardness, θ is the slope, D is the spatial extent of the study area, and t is the time; FVC is the fractional vegetation cover, which was calculated using the NDVI data provided by the HPSDC (Jia & Zhou, ; Yan, Zhan, Qo, Yuan, & Li, ) as follows:

italicFVC = ((), italicNDVI - {NDVI}_{soil}) / ((), {NDVI}_{veg} - {NDVI}_{soil}),

where FVC is the fractional vegetation cover, NDVI is the normalized difference vegetation index of the focal pixel, and NDVI soil and NDVI veg refer to the NDVI of bare soil and dense green vegetation, which were constantly set to 0.0298 and 0.8119, respectively (Zhu, Pan, He, Yu, & Hu, ). The FVC of the water body was simply set to 1.0 because it can completely prevent wind erosion.…”

Section: Methodsmentioning

confidence: 99%

Wind erosion reduction by water diversion in the lower Heihe River Basin, Northwest China

et al. 2018

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The lower Heihe River Basin, a key ecological function zone in Northwest China, has suffered from serious land degradation by wind erosion for decades, posing a great threat to the national ecological safety. This study explores the dynamics of wind erosion and the soil conservation service (SCS) in this region following water diversion during 2001–2010 with the statistic model of wind erosion on small watershed basis based on remote sensing, climate, and soil data, and impacts of driving factors on the SCS are revealed with scenario analysis. Results suggest that the SCS represented by the soil retention amount was less than 500 t km−2 yr−1 in most parts of the study area and higher than 15,000 t km−2 yr−1 in a few wind erosion hotspots, including the East Juyanhai region, Dingxin Oasis, Ejina Oasis, and its surrounding desert–oasis transitional areas. The cumulative potential soil loss of the study area increased much faster than the cumulative soil retention amount, and fractional vegetation cover influenced by the Ecological Water Diversion Project played a dominant role in improving the SCS, accounting for 82.25% of the change in the SCS of the study area. Climate change played a subordinate role, but there were essential separate and interactive effects of climate factors on the SCS. This study provides a preliminary overview of hotspots of wind erosion and the SCS in the lower Heihe River Basin from a geographical perspective, laying a solid basis for combating land degradation by wind erosion in arid regions of Northwest China.

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Multilevel modeling of NPP change and impacts of water resources in the Lower Heihe River Basin

Cited by 22 publications

References 62 publications

Effects of Climate Change and LUCC on Terrestrial Biomass in the Lower Heihe River Basin during 2001–2010

Effects of Climate Change and LUCC on Terrestrial Biomass in the Lower Heihe River Basin during 2001–2010

Land–Atmosphere Exchange of Water and Heat in the Arid Mountainous Grasslands of Central Asia during the Growing Season

Wind erosion reduction by water diversion in the lower Heihe River Basin, Northwest China

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