Variability of soil moisture and its relationship with surface albedo and soil thermal parameters over the Loess Plateau

Guan, Xiaodan; Huang, Jianping; Guo, Na; Bi, Jun; Wang, Guoyin

doi:10.1007/s00376-009-8198-0

Cited by 135 publications

(97 citation statements)

References 17 publications

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“…These discrepancies could be caused by non-uniform daily changes in soil water content before and after rainfall events during the growing seasons. As a result of non-linear changes in the soil particles -water -air paths for heat conduction during wettingdrying processes, both thermal conductivity and heat capacity of soils with different porosity and bulk density usually showed: -a non-linear and more or less rapid increase with increasing soil water content, and -a non-linear decrease with declining soil water content (Guan et al, 2009;Smits et al, 2009;Usowicz, 1995). The results of the sensitivity analysis demonstrated that the soil temperatures predicted by the SWAP model, compared to those after the DNDC model, had a lower variability at the relative changes in daily air temperature ranking from ±4-5% to ±15-17% (Fig.…”

Section: Resultsmentioning

confidence: 99%

Field Validation of DNDC and SWAP Models for Temperature and Water Content of Loamy and Sandy Loam Spodosols

Balashov¹,

Buchkina²,

Rizhiya³

et al. 2014

International Agrophysics

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A b s t r a c t. The objectives of the research were to: fulfil the preliminary assessment of the sensitivity of the soil, water, atmosphere, and plant and denitrification and decomposition models to variations of climate variables based on the existing soil database; validate the soil, water, atmosphere, and plant and denitrification and decomposition modelled outcomes against measured records for soil temperature and water content. The statistical analyses were conducted by the sensitivity analysis, Nash-Sutcliffe efficiency coefficients and root mean square error using measured and modelled variables during three growing seasons. Results of sensitivity analysis demonstrated that: soil temperatures predicted by the soil, water, atmosphere, and plant model showed a more reliable sensitivity to the variations of input air temperatures; soil water content predicted by the denitrification and decomposition model had a better reliability in the sensitivity to daily precipitation changes. The root mean square errors and Nash-Sutcliffe efficiency coefficients demonstrated that: the soil, water, atmosphere, and plant model had a better efficiency in predicting seasonal dynamics of soil temperatures than the denitrification and decomposition model; and among two studied models, the denitrification and decomposition model showed a better capability in predicting the seasonal dynamics of soil water content.K e y w o r d s: agroecosystem modelling, model validation, soil water content, soil temperature, Spodosols

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Section: Resultsmentioning

confidence: 99%

Field Validation of DNDC and SWAP Models for Temperature and Water Content of Loamy and Sandy Loam Spodosols

Balashov¹,

Buchkina²,

Rizhiya³

et al. 2014

International Agrophysics

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“…The formula also referred empirical values from Ginoux et al (2012) and assume r eff = 1.2 µm, ρ = 2600 kg m −3 , Q ext = 2.5, and ε = 0.6 m 2 g −1 . This method not only modifies the maximum standard technique developed by Jordan et al (2010), its derived dust column burden also has a correlation coefficient of 0.73 with the ground-based lidar observation at the Semi-Arid Climate and Environment Observatory of Lanzhou University (SACOL) Guan et al, 2009;Liu et al, 2014), indicating its effectiveness in detecting anthropogenic dust. Figure 1 shows the global distribution of semi-arid regions along with the mean anthropogenic dust column burden from 2007 through 2010, demonstrating the wide spread of anthropogenic dust.…”

Section: Methods For Detecting Anthropogenic Dust Aerosolmentioning

confidence: 99%

The relationship between anthropogenic dust and population over global semi-arid regions

et al. 2016

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Abstract. Although anthropogenic dust has received more attention from the climate research community, its dominant role in the production process is still not identified. In this study, we analysed the relationship between anthropogenic dust and population density/change over global semi-arid regions and found that semi-arid regions are major source regions in producing anthropogenic dust. The results showed that the relationship between anthropogenic dust and population is more obvious in cropland than in other land cover types (crop mosaics, grassland, and urbanized regions) and that the production of anthropogenic dust increases as the population density grows to more than 90 persons km −2 . Four selected semi-arid regions, namely East China, India, North America, and North Africa, were used to explore the relationship between anthropogenic dust production and regional population. The most significant relationship between anthropogenic dust and population occurred in an Indian semi-arid region that had a greater portion of cropland, and the high peak of anthropogenic dust probability appeared with 220 persons km −2 of population density and 60 persons km −2 of population change. These results suggest that the influence of population on production of anthropogenic dust in semi-arid regions is obvious in cropland regions. However, the impact does not always have a positive contribution to the production of anthropogenic dust, and overly excessive population will suppress the increase of anthropogenic dust. Moreover, radiative and climate effects of increasing anthropogenic dust need more investigation.

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“…In the northeastern ecotone between agriculture and animal husbandry, farmland has greater roughness and energy fluxes than the grassland in Tongyu (Feng et al, 2012) but less than the reed wetland in Panjin ). In the degraded grassland in western China, the oasis-desert transition zone is a cold source relative to the Gobi in Dunhuang (Wang et al, 2005;Zhang and Huang, 2004), and energy fluxes are different over different land surface due to vegetation, precipitation, and soil moisture in the Loess Plateau (Huang et al, 2008;Guan et al, 2009;Wang et al, 2010). Moreover, rapid urban expansion has changed heat fluxes in the Pearl River delta considerably (Lin et al, 2009) and has increased sensible heat flux in Beijing ).…”

Section: Introductionmentioning

confidence: 99%

Comparison of land–atmosphere interaction at different surface types in the mid- to lower reaches of the Yangtze River valley

et al. 2016

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Abstract. The mid-to lower reaches of the Yangtze River valley are located within the typical East Asian monsoon zone. Rapid urbanization, industrialization, and development of agriculture have led to fast and complicated land use and land cover change in this region. To investigate landatmosphere interaction in this region where human activities and monsoon climate have considerable interaction with each other, micrometeorological elements over four sites with different surface types around Nanjing, including urban surface at Dangxiao (hereafter DX-urban), suburban surface at Xianling (XL-suburb), and grassland and farmland at Lishui County (LS-grass and LS-crop), are analyzed and their differences are revealed. The impacts of surface parameters of different surface types on the radiation budget and land surface-atmosphere heat, water, and mass exchanges are investigated and compared. The results indicate the following. (1) The largest differences in daily average surface air temperature (T a ), surface skin temperature (T s ), and relative humidity (RH), which are found during the dry periods between DX-urban and LS-crop, can be up to 3.21 • C, 7.26 • C, and 22.79 %, respectively. The diurnal ranges of the above three elements are the smallest at DX-urban and the largest at LS-grass, XL-suburb, and LS-crop. (2) Differences in radiative fluxes are mainly reflected in upward shortwave radiation (USR) that is related to surface albedo and upward longwave radiation (ULR) that is related to T s . When comparing four sites, it can be found that both the smallest USR and the largest ULR occur at the DX-urban site. The diurnal variation in ULR is same as that of T s at all four sites. (3) The differences in daily average sensible heat (H ) and latent heat (LE) between DX-urban and LS-crop are larger than 45 and 95 Wm −2 , respectively. The proportion of latent heat flux in the net radiation (LE/R n ) keeps increasing with the change in season from the spring to summer. (4) Human activities have obvious effects on microclimate. The urban heat island (UHI) effect results in a T a 2 • C higher at the urban site than other sites in the nighttime. At the crop site, LE is dominant due to irrigation, and negative H is observed since evaporation cooling leads to low T s . Although T s is higher at XL-suburb than that at LS-grass, there is no large difference in T a between the two sites due to the distinct effects of the planted forest.

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Variability of soil moisture and its relationship with surface albedo and soil thermal parameters over the Loess Plateau

Abstract: ABSTRACT

Cited by 135 publications

References 17 publications

Field Validation of DNDC and SWAP Models for Temperature and Water Content of Loamy and Sandy Loam Spodosols

Field Validation of DNDC and SWAP Models for Temperature and Water Content of Loamy and Sandy Loam Spodosols

The relationship between anthropogenic dust and population over global semi-arid regions

Comparison of land–atmosphere interaction at different surface types in the mid- to lower reaches of the Yangtze River valley

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