scholarly journals An Overview of the LOess Plateau Mesa Region Land Surface Process Field EXperiment Series (LOPEXs)

2009 ◽  
Vol 6 (1) ◽  
pp. 1003-1019
Author(s):  
J. Wen ◽  
Z. Wei
Keyword(s):  
Field Experiment ◽  
Loess Plateau ◽  
Land Surface ◽  
Chinese Loess Plateau ◽  
Surface Process ◽  
The Loess Plateau ◽  
Research Topics ◽  
Land Surface Process ◽  
Chinese Loess ◽  
The Chinese Loess Plateau

Abstract. An overview of the land surface process field experiment series conducted in the Chinese Loess Plateau mesa region in 2004, 2005, 2006, 2007 and 2008 (abbreviated as LOPEX04, LOPEX05, LOPEX06, LOPEX07 and LOPEX08 hereafter) was presented. The general objectives of the experiment series, observations and preliminary results are summarized and presented in this paper. The research topics proposed by using the LOPEXs datasets are also prospected.

scholarly journals An overview of the LOess Plateau mesa region land surface process field EXperiment series (LOPEXs)

2009 ◽  
Vol 13 (6) ◽  
pp. 945-951 ◽  
Author(s):  
J. Wen ◽  
L. Wang ◽  
Z. G. Wei
Keyword(s):  
Loess Plateau ◽  
Land Surface ◽  
Field Experiments ◽  
Chinese Loess Plateau ◽  
Data Sets ◽  
Surface Process ◽  
Land Surface Process ◽  
Chinese Loess ◽  
Series Of Experiments ◽  
The Chinese Loess Plateau

Abstract. A series of land surface process field experiments were carried out in a mesa region of the Chinese Loess Plateau in each of the years from 2004 to 2008 (acronymized as LOPEX04, LOPEX08, etc.). The general objectives of this series of experiments, observational data sets, and preliminary science results are presented in this paper. The prospective research topics by using the LOPEXs data sets are discussed.

scholarly journals Terrestrial mollusc records from Xifeng and Luochuan L9 loess strata and their implications for paleoclimatic evolution in the Chinese Loess Plateau during marine Oxygen Isotope Stages 24-22

2011 ◽  
Vol 7 (2) ◽  
pp. 349-359 ◽  
Author(s):  
B. Wu ◽  
N. Q. Wu
Keyword(s):  
Loess Plateau ◽  
Climatic Conditions ◽  
Chinese Loess Plateau ◽  
Coarse Grained ◽  
The Loess Plateau ◽  
Climate History ◽  
Chinese Loess ◽  
Terrestrial Mollusc ◽  
General Cooling ◽  
The Chinese Loess Plateau

Abstract. Marine Isotope Stages 24-22 is a key period of the Mid-Pleistocene Transition, however, its climate variability is still unclear. The coarse-grained loess unit L9, one of the most prominent units in the Chinese loess stratigraphy, yields a high potential terrestrial record of paleoclimatic and paleoenvironmental changes during this period. In this study, two high-resolution terrestrial mollusc records of L9 loess strata from the Xifeng and Luochuan sequences in the Chinese Loess Plateau were analysed. Our mollusc results show that the MIS 24, the early and late parts of MIS 22 were dominated by cold and dry climate. Relatively mild-humid climate occurred in MIS 23 and the middle part of MIS 22. The climatic conditions at Xifeng region were cooler and more unstable compared to Luochuan region. A comparison of mollusc species composition and other proxies of L9 strata (MIS 24-22) with those of L1 loess units (MIS 4-2) indicates that the L9 loess was not deposited under the most severe glacial conditions in Quaternary climate history as suggested in previous studies. Our study shows that climatic conditions in the Loess Plateau during the L9 loess forming period were similar to that of gentle glacials (MIS 24 and MIS 22) and interglacial (MIS 23), as suggested by the marine δ18O record. Three cooling fluctuations occurred at ~930 ka, 900 ka and 880 ka, which might hint to the global "900 ka cooling event". The "900-ka event" in the Loess Plateau does not seem to be a simple long glaciation, but rather several complex climatic fluctuations superposed on a general cooling trend. The uplift of the Tibetan Plateau and the general cooling experienced by the Earth during this period may have resulted in abundant dust sources and increased dust transport capability, as indicated by increased grain size and the mass accumulation rate of L9 loess.

scholarly journals Watershed discretization based on multiple factors and its application in the Chinese Loess Plateau

2011 ◽  
Vol 8 (5) ◽  
pp. 9063-9087 ◽  
Author(s):  
Y. Xu ◽  
B. Fu ◽  
C. He ◽  
G. Gao
Keyword(s):  
Land Use ◽  
Loess Plateau ◽  
Assessment Tool ◽  
Chinese Loess Plateau ◽  
Coefficient Of Determination ◽  
The Loess Plateau ◽  
Runoff Simulation ◽  
Chinese Loess ◽  
Land Type ◽  
The Chinese Loess Plateau

Abstract. The spatial discretization of watersheds is an indispensable procedure for representing landscape variations in eco-hydrological research, representing the contrast between reality and data-supported models. When discretizing a watershed, it is important to construct a scheme of a moderate number of discretized factors while adequately considering the actual eco-hydrological processes, especially in regions with unique eco-hydrological features and intense human activities. Because of their special lithological and pedologic characteristics and widespread man-made vegetation, discretization of watersheds in the Loess Plateau in Northern China is a challenge. In order to simulate the rainfall-runoff process, a watershed in the Loess Plateau, referred as Ansai, was spatially discretized into new units called land type units. These land type units were delineated under a scheme of factors including land use, vegetation condition, soil type and slope. Instead of using units delineated by overlaying land use and soil maps, the land type units were used in the Soil and Water Assessment Tool (SWAT). Curve numbers were assigned and adjusted to simulate runoff, using the US Natural Resources Conservation Service (NRCS) curve number method. The results of the runoff simulation better matched actual observations. Compared to the results that used the original units, the coefficient of determination (R2) and the Nash–Sutcliffe coefficient (ENS) for monthly flow simulation increased from 0.710–0.721 and 0.581–0.656 to 0.726–0.731 and 0.692–0.703, respectively. This method of delineating into land type units is an easy operation and suitable approach for eco-hydrological studies in the Chinese Loess Plateau and other similar regions. It can be further applied in soil erosion simulation and the eco-hydrological assessment of re-vegetation.

Impacts of land use change and climatic effects on streamflow in the Chinese Loess Plateau: a meta-analysis

2020 ◽  
Author(s):  
Hao Chen ◽  
Luuk Fleskens ◽  
Jantiene Baartman ◽  
Fei Wang ◽  
Simon Moolenaar ◽  
...  
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Land Use Change ◽  
Loess Plateau ◽  
Meta Analysis ◽  
Chinese Loess Plateau ◽  
Land Restoration ◽  
The Loess Plateau ◽  
Chinese Loess ◽  
The Chinese Loess Plateau

<p><strong>Abstract: </strong>Land use and climate change are recognized as two major drivers affecting surface streamflow. On the Chinese Loess Plateau, implementation of several land restoration projects has changed land cover in recent decades. The main objectives of this study were to understand how streamflow evolved on the Loess Plateau and how land use and climate change have contributed to this change. In this study, we selected 22 hydrological modelling studies covering 25 different watersheds in the Loess Plateau and we performed a meta-analysis by using the hydrological and metrological data collected from these studies. The results indicate a streamflow decrease in 41 of a total of 52 case studies whereas precipitation change was found to be non-significant in the majority of the cases. Streamflow reduction was estimated to be -0.46mm/year by meta-analysis across all case studies. Land use change was estimated to have 63.52% impact on the streamflow reduction whereas climate change accounted for 36.48% of the impact. Using meta-regression, an increasing soil and water conservation area was found to be positively correlated to streamflow reduction. We conclude that in the Chinese Loess Plateau, streamflow shows a decreasing trend and land restoration is the major cause of this reduction. To the knowledge of the authors, this is the first study that estimates streamflow dynamics across many watersheds on the entire Loess Plateau.</p>

scholarly journals Insights into the provenance of the Chinese Loess Plateau from joint zircon U-Pb and garnet geochemical analysis of last glacial loess

2017 ◽  
Vol 89 (3) ◽  
pp. 645-659 ◽  
Author(s):  
Kaja Fenn ◽  
Thomas Stevens ◽  
Anna Bird ◽  
Mara Limonta ◽  
Martin Rittner ◽  
...  
Keyword(s):  
Loess Plateau ◽  
Detrital Zircons ◽  
Chinese Loess Plateau ◽  
Provenance Analysis ◽  
The Loess Plateau ◽  
Chinese Loess ◽  
Last Glacial ◽  
Dust Sources ◽  
Single Grain ◽  
The Chinese Loess Plateau

AbstractThe Chinese Loess Plateau, the world’s largest and oldest loess record, preserves evidence of Asia’s long-term dust source dynamics, but there is uncertainty over the source of the deposits. Recent single-grain detrital zircon U-Pb age analysis has progressed this issue, but debates remain about source changes, and the generation and interpretation of zircon data. To address this, we analyze different groupings of new and existing datasets from the Loess Plateau and potential sources. We also present the results of a first high resolution sampling, multi-proxy provenance analysis of Beiguoyuan loess using U-Pb dating of detrital zircons and detrital garnet geochemistry. The data shows that some small source differences seem to exist between different areas on the Loess Plateau. However, sediment source appears to be unchanging between loess and palaeosols, supporting a recent material recycling hypothesis. Our zircon and garnet data demonstrates, however, that Beiguoyuan experienced a temporary, abrupt source shift during the last glacial maximum, implying that local dust sources became periodically active during the Quaternary. Our results highlight that grouping data to achieve bigger datasets could cause identification of misleading trends. Additionally, we suggest that multi-proxy single-grain approaches are required to gain further insight into Chinese Loess Plateau dust sources.

scholarly journals Watershed discretization based on multiple factors and its application in the Chinese Loess Plateau

2012 ◽  
Vol 16 (1) ◽  
pp. 59-68 ◽  
Author(s):  
Y. D. Xu ◽  
B. J. Fu ◽  
C. S. He ◽  
G. Y. Gao
Keyword(s):  
Land Use ◽  
Loess Plateau ◽  
Assessment Tool ◽  
Chinese Loess Plateau ◽  
Coefficient Of Determination ◽  
The Loess Plateau ◽  
Runoff Simulation ◽  
Chinese Loess ◽  
Land Type ◽  
The Chinese Loess Plateau

Abstract. The spatial discretization of watersheds is an indispensable procedure for representing landscape variations in eco-hydrological research, representing the contrast between reality and data-supported models. When discretizing a watershed, it is important to construct a scheme of a moderate number of discretized factors while adequately considering the actual eco-hydrological processes, especially in regions with unique eco-hydrological features and intense human activities. Because of their special lithological and pedologic characteristics and widespread man-made vegetation, discretization of watersheds in the Loess Plateau in Northern China is a challenge. In order to simulate the rainfall-runoff process, a watershed in the Loess Plateau, referred as Ansai, was spatially discretized into new units called land type units. These land type units were delineated under a scheme of factors including land use, vegetation condition, soil type and slope. Instead of using units delineated by overlaying land use and soil maps, the land type units were used in the Soil and Water Assessment Tool (SWAT). Curve numbers were assigned and adjusted to simulate runoff, using the US Natural Resources Conservation Service (NRCS) curve number method. The results of the runoff simulation better matched actual observations. Compared to the results that used the original units, the coefficient of determination (R2) and the Nash-Sutcliffe coefficient (ENS) for monthly flow simulation increased from 0.655–0.713 and 0.271–0.550 to 0.733–0.745 and 0.649–0.703, respectively. This method of delineating into land type units is an easy operation and suitable approach for eco-hydrological studies in the Chinese Loess Plateau and other similar regions. It can be further applied in soil erosion simulation and the eco-hydrological assessment of re-vegetation.

Episodic gullying and paleomonsoon cycles on the Chinese Loess Plateau

2005 ◽  
Vol 64 (2) ◽  
pp. 234-241 ◽  
Author(s):  
Stephen C. Porter ◽  
Zhisheng An
Keyword(s):  
Loess Plateau ◽  
Central China ◽  
Chinese Loess Plateau ◽  
The Loess Plateau ◽  
Surface Hydrology ◽  
Airborne Dust ◽  
Chinese Loess ◽  
Soil Units ◽  
Cyclic Changes ◽  
The Chinese Loess Plateau

AbstractBuried gullies exposed in road excavations along the margin of a loess tableland on the Loess Plateau of central China lie within a thick loess-paleosol succession that spans ≥780,000 years. Constraining ages for gully cutting and filling are provided by dates of loess and soil units cut by and capping the paleogullies. An episode of gully cutting begins at the onset of an interglaciation and ceases as the gullies begin to fill with colluvium and airborne dust during the transition to full-glacial conditions. The episodic cutting and filling of gullies implies a basic astronomical (orbital) control of gully evolution involving cyclic changes in dominant summer and winter monsoon climates, surface hydrology, and vegetation cover.

scholarly journals Terrestrial mollusc records from Xifeng and Luochuan L9 loess strata and their implications for paleoclimatic evolution in the Chinese Loess Plateau during marine oxygen isotope stages 24–22

2010 ◽  
Vol 6 (6) ◽  
pp. 2767-2793
Author(s):  
B. Wu ◽  
N. Q. Wu
Keyword(s):  
Loess Plateau ◽  
Climatic Conditions ◽  
Chinese Loess Plateau ◽  
Coarse Grained ◽  
The Loess Plateau ◽  
Climate History ◽  
Climatic Fluctuations ◽  
Chinese Loess ◽  
Terrestrial Mollusc ◽  
The Chinese Loess Plateau

Abstract. Marine Isotope Stages 24–22 is a key period of the Mid-Pleistocene Transition, however, its climate variability is still unclear. The coarse-grained loess unit L9, one of the most prominent units in the Chinese loess stratigraphy, yields a high potential terrestrial record of paleoclimatic and paleoenvironmental changes during this period. In this study, two high-resolution terrestrial mollusc records of L9 loess strata from the Xifeng and Luochuan sequences in the Chinese Loess Plateau were analyzed. Our mollusc results show that the MIS 24, the early and late parts of MIS 22 were dominated by cold and dry climate. Relatively mild-humid climate occurred in MIS 23 and the middle part of MIS 22. The climatic conditions at Xifeng region were cooler and more unstable compared to Luochuan region. A comparison of mollusc species composition and other proxies of L9 strata (MIS 24–22) with those of L1 loess units (MIS 4–2) reveals that the L9 loess was not deposited under the most severe glacial conditions in Quaternary climate history as suggested by previous studies. Our study shows that climatic conditions in the Loess Plateau during the L9 loess forming period were like that of gentle glacials (MIS 24 and MIS 22) and interglacial (MIS 23), as suggested by marine δ18O record. Three cooling fluctuations occurred at ~940–923 ka, 905–895 ka and 885–875 ka, which might be hints of the global "900 ka cooling event". The "900-ka event" in the Loess Plateau seems not a simple long glaciation but a complex of several climatic fluctuations superposed on a general cooling trend. The uplift of Tibetan Plateau and its adjacent regions during this period resulted in a rapid increase in source materials of desert and loess and an enhancement of winter monsoon, which would have amplified the effects of cooling climate on dust production and transport during MIS 24–22, as indicated by increased grain size and mass accumulation rate of L9 loess.

scholarly journals Changes in soil water holding capacity and water availability following vegetation restoration on the Chinese Loess Plateau

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yong-wang Zhang ◽  
Kai-bo Wang ◽  
Jun Wang ◽  
Changhai Liu ◽  
Zhou-ping Shangguan
Keyword(s):  
Land Use ◽  
Soil Water ◽  
Loess Plateau ◽  
Soil Layer ◽  
Soil Physical Properties ◽  
Chinese Loess Plateau ◽  
Land Use Type ◽  
Chinese Loess ◽  
Water Holding ◽  
The Chinese Loess Plateau

AbstractChanges in land use type can lead to variations in soil water characteristics. The objective of this study was to identify the responses of soil water holding capacity (SWHC) and soil water availability (SWA) to land use type (grassland, shrubland and forestland). The soil water characteristic curve describes the relationship between gravimetric water content and soil suction. We measured the soil water characteristic parameters representing SWHC and SWA, which we derived from soil water characteristic curves, in the 0–50 cm soil layer at sites representing three land use types in the Ziwuling forest region, located in the central part of the Loess Plateau, China. Our results showed that the SWHC was higher at the woodland site than the grassland and shrubland, and there was no significant difference between the latter two sites, the trend of SWA was similar to the SWHC. From grassland to woodland, the soil physical properties in the 0–50 cm soil layer partially improved, BD was significantly higher at the grassland site than at the shrubland and woodland sites, the clay and silt contents decreased significantly from grassland to shrubland to woodland and sand content showed the opposite pattern, the soil porosity was higher in the shrubland and woodland than that in the grassland, the soil physical properties across the 0–50 cm soil layer improved. Soil texture, porosity and bulk density were the key factors affecting SWHC and SWA. The results of this study provide insight into the effects of vegetation restoration on local hydrological resources and can inform soil water management and land use planning on the Chinese Loess Plateau.

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