Impacts of Land Surface Conditions and Land Use on Dust Events in the Inner Mongolian Grasslands, China

Aeolian processes in temperate grasslands (TGs) are unique because the plant growth–decay cycle, soil water, and land-use interactions affect the seasonal and inter-annual changes in dust events. Land-use types in Inner Mongolian TGs are unique (settled grazing and grass mowing) compared with those in Mongolian TGs. Since 2003, land use has been controlled by grassland protection legislation, which is intended to prevent desertification and dust storms. In this study, we used process-based ecosystem (DAYCENT) and statistical modeling, along with dust event observations from March to June of 1981–2015, to (1) identify critical land surface factors controlling dust emissions (vegetation components, live grass, standing dead grass, litter, and soil moisture) at typical and desert steppe sites in Inner Mongolia and (2) estimate the impact of controlled land-use legislation on dust events. The DAYCENT model realistically simulated the dynamics of the observed vegetation components and soil moisture in 2005–2015. At both sites, similar significant correlations were obtained between spring dust events and wind speed or a combination of all surface factors that retained anomalies (memory) from the preceding year. Among the surface factors, vegetation was a critical factor that suppressed dust in Inner Mongolian TGs, similar to that in Mongolian TGs. In the desert steppe, standing dead grass had the strongest memory and was significantly correlated with dust events, whereas no significant correlations were observed in the typical steppe. This suggests that, in a typical steppe region, heavy grazing and mowing result in few dead grasses, thereby inhibiting the prevention of dust events. Moreover, the simulations of dust events under controlled (light grazing) and uncontrolled (heavy grazing) land-use conditions demonstrated that the grassland protection legislation reduced the occurrence of dust events in typical and desert steppe sites by 25 and 40%, respectively, since 2003.

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Estimating the Effects of DEM and Land Use Types on Soil Moisture Using HJ-1A CCD/IRS Images: A Case Study in Minhou County

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.726-731.4572 ◽

2013 ◽

Vol 726-731 ◽

pp. 4572-4576 ◽

Cited By ~ 1

Author(s):

Yu Qin Liu ◽

Jin Ming Sha ◽

De Sheng Wang

Keyword(s):

Land Use ◽

Soil Moisture ◽

Land Surface ◽

Vegetation Index ◽

Vegetation Indexes ◽

Land Use Types ◽

Research Findings ◽

Soil Moisture Status

Soil moisture is of great significance for regional resources and environments. The combination of land surface temperature (Ts) and vegetation index (VI) is appropriate for monitoring the regional surface soil moisture status. In this study, we employed HJ-1B CCD/IRS images,DEMand land use types to obtain the information about soil moisture for Minhou county in FuZhou. Firstly,TVDIreflected the soil moisture status was analyzed with in-situ soil moisture measurements based on two kinds of different vegetation indexes (NDVI/EVI). Secondly, the relationship betweenTVDIandDEMwas analyzed. Finally, the soil moisture status of each land use type was explored combined with the main land use types of study area. Research findings indicate that: (1)TVDIcan effectively reflect the spatial pattern of soil moisture andTs/EVIhas a higher accuracy thanTs/NDVI; (2) the spatial distribution of soil moisture is obviously affected by the altitude; (3) there exists correlationship between soil moisture and land use types in study area.

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Impacts of inhomogeneous landscapes in oasis interior on the oasis self-maintaining mechanism by integrating numerical model with satellite data

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-9-1979-2012 ◽

2012 ◽

Vol 9 (2) ◽

pp. 1979-2004

Author(s):

X. Meng ◽

S. Lu ◽

T. Zhang ◽

Y. Ao ◽

S. Li ◽

...

Keyword(s):

Land Use ◽

Surface Layer ◽

Soil Moisture ◽

Land Surface ◽

Negative Impact ◽

Remote Sensing Data ◽

Vegetation Fraction ◽

First Case ◽

Land Use Types ◽

Meteorological Modeling

Abstract. Mesoscale meteorological modeling is an important tool to help understand the energy budget of the oasis. While basic dynamic and thermodynamic processes for oasis self-maintaining in the desert environment is well investigated, influence of heterogeneous landscapes of oasis interior on the processes are still important and remain to be investigated. In this study, two simulations are designed for investigating the influence of inhomogeneity. In the first case, land surface parameters including land-use types, vegetation cover fraction, and surface layer soil moisture are derived by satellite remote sensing data from EOS/MODIS, and then be used specify the respective options in the MM5 model, to describe a real inhomogeneity for the oasis interior. In the other run, land use types are set to MM5 default, in which landscapes in the oasis interior is relative uniform, and then surface layer soil moisture and vegetation fraction is set to be averages of the first case for the respective oasis and desert surface lying, to represent a relative homogeneity. Results show that the inhomogeneity leads to a weaker oasis "cold-wet island" effect and a stronger turbulence over the oasis interior, both of which will reduce the oasis-desert secondary circulation and increase the evaporation over the oasis, resulting in a negative impact on the oasis self-protecting mechanism. The simulation of homogeneity indicates that the oasis may be more stable even with relative lower soil moisture if landscapes in the oasis interior are comparatively uniform.

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Contrasting roles of interception and transpiration in the hydrological cycle – Part 1: Simple Terrestrial Evaporation to Atmosphere Model

Earth System Dynamics Discussions ◽

10.5194/esdd-5-203-2014 ◽

2014 ◽

Vol 5 (1) ◽

pp. 203-279 ◽

Cited By ~ 2

Author(s):

L. Wang-Erlandsson ◽

R. J. van der Ent ◽

L. J. Gordon ◽

H. H. G. Savenije

Keyword(s):

Land Use ◽

Soil Moisture ◽

Land Use Change ◽

Time Scale ◽

Land Surface ◽

Hydrological Cycle ◽

Open Water ◽

Climate Conditions ◽

Land Use Types ◽

Atmosphere Model

Abstract. Terrestrial evaporation consists of biophysical (i.e., transpiration) and physical fluxes (i.e., interception, soil moisture, and open water). The partitioning between them depends on both climate and the land surface, and determines the time scale of evaporation. However, few land-surface models have analysed and evaluated evaporative partitioning based on land use, and no studies have examined their subsequent paths in the atmosphere. This paper constitutes the first of two companion papers that investigate the contrasting effects of interception and transpiration in the hydrological cycle. Here, we present STEAM (Simple Terrestrial Evaporation to Atmosphere Model) used to produce partitioned evaporation and analyse the characteristics of different evaporation fluxes on land. STEAM represents 19 land-use types (including irrigated land) at sub-grid level with a limited set of parameters, and includes phenology and stress functions to respond to changes in climate conditions. Using ERA-Interim reanalysis forcing for the years 1999–2008, STEAM estimates a mean global terrestrial evaporation of 73 800 km3 year−1, with a transpiration ratio of 59%. We show that the terrestrial residence time scale of transpiration (days to months) has larger inter-seasonal variation and is substantially longer than that of interception (hours). Furthermore, results from an offline land-use change experiment illustrate that land-use change may lead to significant changes in evaporative partitioning even when total evaporation remains similar. In agreement with previous research, our simulations suggest that the vegetation's ability to transpire by retaining and accessing soil moisture at greater depth is critical for sustained evaporation during the dry season. Despite a relatively simple model structure, validation shows that STEAM produces realistic evaporative partitioning and hydrological fluxes that compare well with other global estimates over different locations, seasons and land-use types. We conclude that the simulated evaporation partitioning by STEAM is useful for understanding the links between land use and water resources, and can with benefit be employed for atmospheric moisture tracking.

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Land-use change may exacerbate climate change impacts on water resources in the Ganges basin

Hydrology and Earth System Sciences Discussions ◽

10.5194/hess-2017-468 ◽

2017 ◽

pp. 1-33

Author(s):

Gina Tsarouchi ◽

Wouter Buytaert

Keyword(s):

Climate Change ◽

Land Use ◽

Soil Moisture ◽

Water Resources ◽

Land Use Change ◽

River Basin ◽

Land Surface ◽

Surface Model ◽

Climate Change Scenarios ◽

Northern India

Quantifying how land-use change and climate change affect water resources is a challenge in hydrological science. The Upper Ganges (UG) river basin in northern India experiences monsoon flooding almost every year. Studies have shown evidence of strong coupling between the land surface (soil moisture) and atmosphere (precipitation) in northern India, which means that regional climate variations and changes in land use/cover could influence the temporal dynamics of land-atmosphere interactions. This work aims to quantify how future projections of land-use and climate change are affecting the hydrological response of the UG river basin. Two different sets of modelling experiments were run using the JULES Land Surface Model and covering the period 2000&ndash;2035: In the first set, climate change is taken into account, as JULES was driven by the CMIP5 (Coupled Model Intercomparison Project Phase 5) outputs of 21 models, under two Representative Concentration Pathways (RCP4.5 & RCP8.5), whilst land use was kept constant at year 2010. In the second set, both climate change and land-use change were taken into consideration, as apart from the CMIP5 model outputs, JULES was also forced with a time-series of 15 future land-use scenarios, based on Landsat satellite imagery and Markov chain simulation. Variations in hydrological variables (stream flow, evapotranspiration and soil moisture) are calculated during the simulation period. Significant changes in the near-future (years 2030&ndash;2035) hydrologic fluxes arise under future land cover and climate change scenarios pointing towards a severe increase in high extremes of flow: the multi-model mean of the 95th percentile of streamflow [Q5] is projected to increase by 63&thinsp;% under the combined land-use and climate change high emissions scenario [RCP8.5]. The changes in all examined hydrological components are greater in the combined land-use and climate change experiment. Results are further presented in a water resources context, aiming to address potential implications of climate change from a water-demand perspective, highlighting that that demand thresholds in the UG region are projected to be exceeded in the future winter months (Dec&ndash;Feb).

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