scholarly journals The influences of air heat storage, plant photosynthesis and soil water movement on surface energy balance over the loess plateau

2012 ◽  
Vol 61 (15) ◽  
pp. 159201
Author(s):  
Li Hong-Yu ◽  
Zhang Qiang ◽  
Wang Chun-Ling ◽  
Yang Fu-Lin ◽  
Zhao Jian-Hua
Keyword(s):  
Energy Balance ◽  
Surface Energy ◽  
Soil Water ◽  
Loess Plateau ◽  
Surface Energy Balance ◽  
Heat Storage ◽  
Water Movement ◽  
The Loess Plateau ◽  
Plant Photosynthesis ◽  
Soil Water Movement

scholarly journals Soil Freeze-Thaw and Water Transport Characteristics Under Different Vegetation Types in Seasonal Freeze-Thaw Areas of the Loess Plateau

2021 ◽  
Vol 9 ◽  
Author(s):  
Lanfeng Bo ◽  
Zhanbin Li ◽  
Peng Li ◽  
Guoche Xu ◽  
Lie Xiao ◽  
...  
Keyword(s):  
Soil Water ◽  
Loess Plateau ◽  
Water Movement ◽  
Vegetation Types ◽  
The Loess Plateau ◽  
Freezing And Thawing ◽  
Freezing Period ◽  
Thawing Processes ◽  
Semi Arid ◽  
Soil Water Movement

In the arid and semi-arid regions of the Loess Plateau, seasonal freezing and thawing influence soil water movement, and water movement directly influences vegetation growth. However, currently, research with regard to freezing and thawing processes under various vegetation types and the mechanism of soil water movement is lacking. Therefore, the present study explored soil water migration characteristics of two typical vegetation types [arbor land (AL) and shrub land (SL)] on the Loess Plateau during seasonal freezing and thawing processes using bare land (BL) as a control. We used field measured data for hourly soil temperature (ST) and soil water content (SWC) at a depth of 100 cm below the soil surface from November 2017 to March 2018. Freezing and thawing process was divided into three stages based on ST change (initial freezing period, stable freezing period, and thawing period). Compared with previous studies in this area, ST is lower than expected, and SWC migration characteristics are also different. The results revealed that: 1) the maximum freezing depth of AL and SL was 60 cm, which was 30 cm less than that of BL. The freezing date of each soil layer in BL was the earliest and average ST value was the lowest. BL had the highest degree of freezing. The freezing of all soil layers in AL occurred at a later date than that of SL. ST and the minimum soil freezing temperatures were higher than those of SL, and the capacity of AL to resist freezing was higher; 2) the SWCs in AL and BL at depths of 0–10 cm and 10–30 cm decreased, whereas SWCs of AL and BL at a depth of 60 cm increased by 152 and 146%, respectively. The SWCs of SL at soil depths of 0–10 cm, 10–30 cm, and 30–60 cm increased by 46.3, 78.4 and 205%, respectively. The amount and distribution of soil moisture in SL were optimum when compared to those of AL and BL. The results of the present study could provide a scientific basis for vegetation restoration in arid and semi-arid areas of the Loess Plateau.

scholarly journals Soil Water Movement Changes Associated with Revegetation on the Loess Plateau of China

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 731 ◽  
Author(s):  
Haocheng Ke ◽  
Peng Li ◽  
Zhanbin Li ◽  
Peng Shi ◽  
Jingming Hou
Keyword(s):  
Soil Water ◽  
Loess Plateau ◽  
Large Scale ◽  
Plant Density ◽  
Water Movement ◽  
Temporal Distribution ◽  
Semiarid Region ◽  
The Loess Plateau ◽  
Vegetation Growth ◽  
Soil Water Movement

Soil water is the limitation factors in the semiarid region for vegetation growth. With the large scale “Grain for Green” implementation on the Loess Plateau of China, an amount of sloping cropland was converted to forestland, shrubland, and grassland. The spatial and temporal distribution of soil water was changed. However, the effect of revegetation on soil water movement is still unclear. In this study, we analyze the stable isotopes changes in precipitation and soil water in sloping cropland, forestland, shrubland, and grassland to trace the movement of moisture in soil. The results showed that δ18O in shallow layers (<20 cm depth) of sloping cropland, forestland, shrubland, and grassland were −3.54‰, −2.68‰, −4.00‰, and −3.16‰, respectively. The δ18O in these layers were higher than that in the lower layers, indicating that evaporation was mainly from the shallow layers. The δ18O for the soil water in the unsaturated zone in the grassland, shrubland, and forestland of the temporal variability decreases with depth and approaches a minimum value at 160 cm, 180 cm, and 200 cm, respectively, suggesting that the soil water is relatively stable many months or even longer. Precipitation was infiltrated with piston and preferential modes, and infiltration demonstrated obvious mixing. Present study demonstrated the δ18O was more sensitive than the soil water content for tracing the maximum infiltration depth of event water and recharge mechanisms. Consequently, we suggested that the land user management such as type, plant density should be considered in the revegetation.

scholarly journals Impact of Increasing Urban Density on Local Climate: Spatial and Temporal Variations in the Surface Energy Balance in Melbourne, Australia

2007 ◽  
Vol 46 (4) ◽  
pp. 477-493 ◽  
Author(s):  
Andrew M. Coutts ◽  
Jason Beringer ◽  
Nigel J. Tapper
Keyword(s):  
Energy Balance ◽  
Surface Energy ◽  
Land Surface ◽  
Surface Energy Balance ◽  
Heat Storage ◽  
Surface Characteristics ◽  
Housing Density ◽  
Local Climate ◽  
Urban Sites ◽  
Land Surface Characteristics

Abstract Variations in urban surface characteristics are known to alter the local climate through modification of land surface processes that influence the surface energy balance and boundary layer and lead to distinct urban climates. In Melbourne, Australia, urban densities are planned to increase under a new strategic urban plan. Using the eddy covariance technique, this study aimed to determine the impact of increasing housing density on the surface energy balance and to investigate the relationship to Melbourne’s local climate. Across four sites of increasing housing density and varying land surface characteristics (three urban and one rural), it was found that the partitioning of available energy was similar at all three urban sites. Bowen ratios were consistently greater than 1 throughout the year at the urban sites (often as high as 5) and were higher than the rural site (less than 1) because of reduced evapotranspiration. The greatest difference among sites was seen in urban heat storage, which was influenced by urban canopy complexity, albedo, and thermal admittance. Resulting daily surface temperatures were therefore different among the urban sites, yet differences in above-canopy daytime air temperatures were small because of similar energy partitioning and efficient mixing. However, greater nocturnal temperatures were observed with increasing density as a result of variations in heat storage release that are in part due to urban canyon morphology. Knowledge of the surface energy balance is imperative for urban planning schemes because there is a possibility for manipulation of land surface characteristics for improved urban climates.

scholarly journals Estimation of actual evapotranspiration of Mediterranean perennial crops by means of remote-sensing based surface energy balance models

2009 ◽  
Vol 13 (7) ◽  
pp. 1061-1074 ◽  
Author(s):  
M. Minacapilli ◽  
C. Agnese ◽  
F. Blanda ◽  
C. Cammalleri ◽  
G. Ciraolo ◽  
...  
Keyword(s):  
Energy Balance ◽  
Surface Energy ◽  
Water Balance ◽  
Soil Water ◽  
Surface Energy Balance ◽  
Soil Water Balance ◽  
Actual Evapotranspiration ◽  
Balance Model ◽  
Spatially Distributed ◽  
Energy Balance Models

Abstract. Actual evapotranspiration from typical Mediterranean crops has been assessed in a Sicilian study area by using surface energy balance (SEB) and soil-water balance models. Both modelling approaches use remotely sensed data to estimate evapotranspiration fluxes in a spatially distributed way. The first approach exploits visible (VIS), near-infrared (NIR) and thermal (TIR) observations to solve the surface energy balance equation whereas the soil-water balance model uses only VIS-NIR data to detect the spatial variability of crop parameters. Considering that the study area is characterized by typical spatially sparse Mediterranean vegetation, i.e. olive, citrus and vineyards, alternating bare soil and canopy, we focused the attention on the main conceptual differences between one-source and two-sources energy balance models. Two different models have been tested: the widely used one-source SEBAL model, where soil and vegetation are considered as the sole source (mostly appropriate in the case of uniform vegetation coverage) and the two-sources TSEB model, where soil and vegetation components of the surface energy balance are treated separately. Actual evapotranspiration estimates by means of the two surface energy balance models have been compared vs. the outputs of the agro-hydrological SWAP model, which was applied in a spatially distributed way to simulate one-dimensional water flow in the soil-plant-atmosphere continuum. Remote sensing data in the VIS and NIR spectral ranges have been used to infer spatially distributed vegetation parameters needed to set up the upper boundary condition of SWAP. Actual evapotranspiration values obtained from the application of the soil water balance model SWAP have been considered as the reference to be used for energy balance models accuracy assessment. Airborne hyperspectral data acquired during a NERC (Natural Environment Research Council, UK) campaign in 2005 have been used. The results of this investigation seem to prove a slightly better agreement between SWAP and TSEB for some fields of the study area. Further investigations are programmed in order to confirm these indications.

scholarly journals Spatiotemporal Variability of Heat Storage in Major U.S. Cities—A Satellite-Based Analysis

2020 ◽  
Vol 13 (1) ◽  
pp. 59
Author(s):  
Joshua Hrisko ◽  
Prathap Ramamurthy ◽  
David Melecio-Vázquez ◽  
Jorge E. Gonzalez
Keyword(s):  
New York ◽  
Energy Balance ◽  
Surface Energy ◽  
Surface Temperature ◽  
Land Surface ◽  
Surface Energy Balance ◽  
Heat Storage ◽  
Numerical Weather ◽  
Numerical Weather Model ◽  
Weather Model

Heat storage, ΔQs, is quantified for 10 major U.S. cities using a method called the thermal variability scheme (TVS), which incorporates urban thermal mass parameters and the variability of land surface temperatures. The remotely sensed land surface temperature (LST) is retrieved from the GOES-16 satellite and is used in conjunction with high spatial resolution land cover and imperviousness classes. New York City is first used as a testing ground to compare the satellite-derived heat storage model to two other methods: a surface energy balance (SEB) residual derived from numerical weather model fluxes, and a residual calculated from ground-based eddy covariance flux tower measurements. The satellite determination of ΔQs was found to fall between the residual method predicted by both the numerical weather model and the surface flux stations. The GOES-16 LST was then downscaled to 1-km using the WRF surface temperature output, which resulted in a higher spatial representation of storage heat in cities. The subsequent model was used to predict the total heat stored across 10 major urban areas across the contiguous United States for August 2019. The analysis presents a positive correlation between population density and heat storage, where higher density cities such as New York and Chicago have a higher capacity to store heat when compared to lower density cities such as Houston or Dallas. Application of the TVS ultimately has the potential to improve closure of the urban surface energy balance.

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