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Paddy and Water Environment - Water adaptation strategies are necessary for decreasing climate change impacts on local societies. This study models a community water supply system as a distributed... 相似文献
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A procedure to determine soil moisture threshold (θ*), cover coefficient (k c), and parameters of soil moisture stress function (k s) is proposed in this study. These coefficients can be further applied to estimate daily actual evapotranspiration in a hydrological model. Two soil moisture stress functions are used to describe k s. One of the functions is proposed by this study, which assumes moisture stress is inversely proportional to matric potential described by van Genuchten retention curve. The procedure is applied to identify the coefficients for three kinds of reference potential evapotranspiration based on soil moisture monitoring. Soil moisture was measured by Watermark soil moisture sensors. These sensors were tested in a laboratory to establish the relationship between soil moisture and recorded tensor. Then, these sensors were installed in an experimental forest watershed. The verification study shows that the calibrated coefficients can provide reasonable estimate of actual evapotranspiration. The R 2 = 0.85 for using the Penman–Montieth equation for tall maize along with k c = 1.81 can be obtained for the validation period with soil moisture stress. Besides, the results also indicate the proposed soil moisture stress function can have better performance on estimating daily actual evapotranspiration at early stage of a dry period. The proposed procedure and soil moisture stress functions can be successfully applied to estimate daily evapotranspiration when soil moisture is known. However, their performance in a hydrological model requires further study, since a hydrological model can only provide estimated soil moisture. 相似文献
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The gradually increased temperature resulting from the enhanced greenhouse effects has been found to be an important factor
of changes to the global climate which in turn might significantly affect the Earth's hydrological cycles. The possible outcomes
of warming climate are changes of precipitation, surface runoff, evapotranspiration, and frequency of extreme weather events,
such as floods and droughts. However, such changes at the global scale may not reflect the variations on a regional scale,
and more so at the local scale. In this study, a physically based water balance model was applied to study the impact of climate
change on the land hydrology, focusing on trends of surface runoff, evapotranspiration, and infiltration in Taiwan. Model
forcing of composite temperatures and precipitations were generated by a weather generation model in association with nine
climate change scenarios, including outputs of equilibrium experiments and special reports on emissions scenarios, from the
IPCC. Although discrepancies among different climate change scenarios are significant, the trend of more extreme precipitations
and surface runoffs were observed in most scenarios' runs. The increase of evapotranspiration in both wet and dry seasons
is persistent among different scenarios throughout the island due to the projected consistently higher temperature. Although
the trends of infiltration for wet and dry seasons are opposite in curtain scenarios, a decreased yearly infiltration was
found in most cases as the result of increased precipitation intensity and more evapotranspiration. Timely adaption measures
for water resources managements and natural hazard mitigations are required to face these changes of land hydrology components
under changing climate. 相似文献
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The arrangement of land use substantially affects outdoor human comfort. The purposes of this study were to develop a spatial optimization procedure that involves combining simulated annealing algorithm with a microclimate model (ENVI-met) and to identify the relationship between the spatial pattern of the major cooling source and human comfort. The procedure is an assessment tool for appropriately designing living space on a community scale. The physiological equivalent temperature (PET) was used as the index of human comfort, and the objective of optimization was to minimize the difference in the PET to 23 °C within the study area. Four types of land use, namely buildings, paddies, parks, and ponds, were considered. Given the types of land use and the land areas, the procedure is used to determine the optimal layout that provides the most comfortable environment. The results revealed that the optimal design effectively improved the homogeneity of human comfort quantitatively and spatially in summer. Human comfort in the entire area was improved when the prevailing wind first passes through cooling sources, such as the paddies, and the walkways are easier to cool when the cooling sources are located nearby. The results of the spatial optimization procedure can further be applied to determine the relationship between the spatial pattern of land use and human comfort, and the relationship can be used as a reference for future research on community design. 相似文献
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The major uncertainty in the climate change impact study inherits from applying the predictions of General Circulation Models
(GCMs). Different results might be obtained by using various GCMs’ predictions, which causes difficulties on the decision
making of water resources management. This study proposed an integrated hydrological simulations and optimization framework,
consisting of a fuzzy linear programming model with interval numbers, a streamflow simulation model, and agricultural water
demand projections, to evaluate the impacts of climate change on reservoir active storage. The reservoir inflows are simulated
by the WatBal model, while agricultural water demands are predicted based on the projected change of potential evapotranspiration.
Inflows and water demands are used to formulate an interval number fuzzy linear programming model. Fuzzy relationships are
used to describe tolerable deficits of water resources, and the interval number is employed to indicate ranges of possible
inflows and water demands. This systematic framework is applied to study the Tsengwen reservoir watershed to provide an optimal
interval of active storage. The results further indicate the higher tolerable deficit, the smaller difference between superior
and inferior active storage. 相似文献
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