A numerical modeling study on desert oasis self-supporting mechanisms

Chu, Peter C.; Lü, Sihua; Chen, Yu‐Chun

doi:10.1016/j.jhydrol.2005.02.043

Cited by 48 publications

(74 citation statements)

References 21 publications

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“…Following similar simulations for oasisdesert mesoscale circulation in previous works (Chu et al, 2005;Lu et al, 2004aLu et al, , 2005, the first 30 h of each simulation were skipped as spin-up time. Hereafter, the simulations from 00:00 BT on 6 July 2004 to 23:00 BT on 9 July 2004 were used for the analysis.…”

Section: Numerical Simulationsmentioning

confidence: 99%

“…According to land surface energy balance, the equations over the oasis and the desert can be expressed as (Holloway and Manabe, 1971;Lu et al, 2004b;Chu et al, 2005) where R n , H , λE and G are the net radiation, sensible heat flux, latent heat flux, and soil heat flux at the oasis (denoted as O ) and the desert (denoted as D ), respectively. The difference of the surface energy balance between the oasis and the desert is represented by…”

Section: Surface Heat Flux Heterogeneitymentioning

confidence: 99%

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

Meng

Lü

Zhang

et al. 2012

Hydrol. Earth Syst. Sci.

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Abstract. The impacts of inhomogeneity of the oasis interior on the oasis self-maintenance mechanism are investigated by using the mesoscale model MM5 (the fifth-generation Pennsylvania State University National Center for Atmospheric Research (NCAR) mesoscale model) with satellite observations of land use types, vegetation fraction and surface-layer soil moisture from MODIS (Moderate Resolution Imaging Spectroradiometer) data. Four simulations were performed, among which the CTL (control simulation) and MOD (moderated simulation with parameters replaced by MODIS data) were used to validate the model results; EXP1 (experiment 1) and EXP2 (experiment 2) were designed to study the inhomogeneity of oasis interior. Results show that the changes of oasis heterogeneity influence the surface heat-flux partitioning, which leads to a larger "cold-wet" effect over the oasis. Vertical sections of humidity illustrate the existence of a moisture-inversion level, and the deeper moisture inversion of EXP1 and EXP2 further indicates that the relative homogeneity in the oasis interior helps produce stronger humidity inversion over the oasis, thus limiting evaporation. This is further verified by the analysis of the secondary circulation, which shows that the more homogeneous land surface conditions lead to stronger secondary circulation and less turbulent drafts over the oasis interior, playing a positive role in the oasis self-maintenance and development.

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Section: Numerical Simulationsmentioning

confidence: 99%

Section: Surface Heat Flux Heterogeneitymentioning

confidence: 99%

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

Meng

Lü

Zhang

et al. 2012

Hydrol. Earth Syst. Sci.

View full text Add to dashboard Cite

show abstract

“…Gates et al, 2008a;Ma et al, 2008Ma et al, , 2009Ma et al, , 2012Huang and Wen, 2014) and atmosphericcirculation modelling studies (e.g. Gao et al, 2004;Chu et al, 2005;Meng et al, 2009Meng et al, , 2012Meng et al, , 2015Wen et al, 2012). Many of these studies involve coarse spatio-temporal resolutions.…”

Section: Introductionmentioning

confidence: 99%

“…Oases in the area provide important refugia to flora, fauna, and humans alike. Oases in north-west China occupy about 5 % of the total land mass of the region, but give refuge to and feed about 95 % of the growing population of the area (Gao et al, 2004;Chu et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Relating seasonal dynamics of enhanced vegetation index to the recycling of water in two endorheic river basins in north-west China

Matin

Bourque

2015

Hydrol. Earth Syst. Sci.

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Abstract. This study associates the dynamics of enhanced vegetation index in lowland desert oases to the recycling of water in two endorheic (hydrologically closed) river basins in Gansu Province, north-west China, along a gradient of elevation zones and land cover types. Each river basin was subdivided into four elevation zones representative of (i) oasis plains and foothills, and (ii) low-, (iii) mid-, and (iv) highmountain elevations. Comparison of monthly vegetation phenology with precipitation and snowmelt dynamics within the same basins over a 10-year period (2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009) suggested that the onset of the precipitation season (cumulative % precipitation > 7-8 %) in the mountains, typically in late April to early May, was triggered by the greening of vegetation and increased production of water vapour at the base of the mountains. Seasonal evolution of in-mountain precipitation correlated fairly well with the temporal variation in oasisvegetation coverage and phenology characterised by monthly enhanced vegetation index, yielding coefficients of determination of 0.65 and 0.85 for the two basins. Convergent cross-mapping of related time series indicated bi-directional causality (feedback) between the two variables. Comparisons between same-zone monthly precipitation amounts and enhanced vegetation index provided weaker correlations. Start of the growing season in the oases was shown to coincide with favourable spring warming and discharge of meltwater from low-to mid-elevations of the Qilian Mountains (zones 1 and 2) in mid-to-late March. In terms of plant requirement for water, mid-seasonal development of oasis vegetation was seen to be controlled to a greater extent by the production of rain in the mountains. Comparison of water volumes associated with in-basin production of rainfall and snowmelt with that associated with evaporation seemed to suggest that about 90 % of the available liquid water (i.e. mostly in the form of direct rainfall and snowmelt in the mountains) was recycled locally.

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“…Five nested grids and 25 vertical levels illustrated by Chu et al (2005) are used. The vertical spacing is 200 m near the surface and increases to 800 m above 2400 m. The vertical grid structure is the same for all five nested grids.…”

Section: Boundary and Initial Conditionsmentioning

confidence: 99%