Canopy Rainfall Research Articles

荒漠草原中间锦鸡儿冠层截留特征

PDF HTML阅读 XML下载 导出引用 引用提醒 荒漠草原中间锦鸡儿冠层截留特征 DOI: 10.5846/stxb201806301441 作者: 作者单位: 宁夏大学西北土地退化与生态恢复省部共建国家重点实验室培育基地／西北退化生态系统恢复与重建教育部重点实验室,宁夏大学西北土地退化与生态恢复省部共建国家重点实验室培育基地／西北退化生态系统恢复与重建教育部重点实验室,宁夏大学西北土地退化与生态恢复省部共建国家重点实验室培育基地／西北退化生态系统恢复与重建教育部重点实验室,宁夏大学西北退化生态系统恢复与重建教育部重点实验室,宁夏大学西北土地退化与生态恢复省部共建国家重点实验室培育基地／西北退化生态系统恢复与重建教育部重点实验室,宁夏大学西北土地退化与生态恢复省部共建国家重点实验室培育基地／西北退化生态系统恢复与重建教育部重点实验室,宁夏大学西北土地退化与生态恢复省部共建国家重点实验室培育基地／西北退化生态系统恢复与重建教育部重点实验室 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（31460161），宁夏大学西部一流学科建设项目（NXYLXK2017B06），宁夏大学西部一流大学建设项目（GZXM2017001），宁夏大学研究生创新项目（GIP2019043） Characteristics of canopy interception by Caragana intermedia in desert grasslands Author: Affiliation: Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration in Northwest China/Ministry of Education Key Laboratory for Ecosystem in Northwest China,Ningxia University,Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration in Northwest China/Ministry of Education Key Laboratory for Ecosystem in Northwest China,Ningxia University,Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration in Northwest China/Ministry of Education Key Laboratory for Ecosystem in Northwest China,Ningxia University,Ministry of Education Key Laboratory for Ecosystem in Northwest China,Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration in Northwest China/Ministry of Education Key Laboratory for Ecosystem in Northwest China,Ningxia University,Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration in Northwest China/Ministry of Education Key Laboratory for Ecosystem in Northwest China,Ningxia University,Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration in Northwest China/Ministry of Education Key Laboratory for Ecosystem in Northwest China,Ningxia University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:以荒漠草原人工中间锦鸡儿（Caragana intermedia）为研究对象，利用2016-2017年监测获取的26次降雨事件，对比分析了两组灌丛（自然组和人工组）的冠层截留特征。结果表明：（1）试验期间共观测到有效降雨33次，总降雨量为251 mm，次平均降雨量和降雨强度分别为7.6 mm和1.14 mm/h，以雨量<2 mm，雨强<1 mm/h和降雨历时2-5 h的降雨出现次数最多；（2）自然组和人工组中间锦鸡儿平均截留量分别为1.11 mm和0.72 mm，平均截留率分别为24.81%和15.95%，两组灌丛截留存在极显著差异（P < 0.01）；（3）在雨量级>15 mm时，自然组（4.57%，CV=73.38%）和人工组（5.25%，CV=51.96%）平均截留率变异性相差最大；（4）自然组和人工组截留量与降雨量，降雨历时和降雨强度之间的关系可以用幂函数描述，截留率与三者的关系均用指数函数描述较好。在降雨特征相同的情况下，灌丛形态特征是影响中间锦鸡儿冠层截留的关键因素。 Abstract:Canopy interception, an important component of water balance in arid and semiarid environments, plays a key role in re-vegetation and the hydrological cycle. Research regarding canopy rainfall interception across the sand-stabilizing shrub, Caragana intermedia, can aid in the elucidation of the eco-hydrological mechanism in desert grasslands. In this study, planted C. intermedia in a desert grassland was selected, and characteristics of canopy interception in two groups of shrubs (natural and planted) were compared and analyzed by monitoring 26 rainfall events from 2016 to 2017. The results showed that a total of 33 effective rainfall events were observed during the experiment, and the total and average amounts, and intensity of rainfall were 251 mm, 7.6 mm, and 1.14 mm/h, respectively. Overall, rainfall events of less than 2 mm and 1 mm/h, as well as a 2-5 h duration had the highest frequency. The average interception of C. intermedia in the natural and planted groups were 1.11 mm and 0.72 mm, respectively, and the average interception percentages were 24.81% and 15.95%, respectively. Significant differences (P < 0.01) in interception were detected between the two groups. When the rainfall amount was greater than 15 mm, the natural group (4.57%, CV=73.38%) and the planted group (5.25%, CV=51.96%) exhibited the greatest differences in average interception percentages. Small amounts of rainfall contributed to a higher percentage of interception. Furthermore, the interception amount of the natural and planted group exhibited a power function that tended to decrease with increasing rainfall amount, duration, and intensity, whereas the interception percentage for the two groups had an obvious exponential function in the relationship with the rainfall amount, duration, and intensity. The canopy interception of planted C. intermedia was significantly reduced, which was conducive to the improvement of the efficiency of precipitation utilization and is of great significance in the elucidation of the hydrological mechanism of decline of canopy interception by planted vegetation. Morphological characteristics of shrubs were the key factors affecting the canopy interception of C. intermedia under the same rainfall conditions. Based on the morphological structures of different shrubs, the canopy structure (height, crown projection area, leaf area) affected canopy interception progress of shrubs. 参考文献 相似文献 引证文献

Water balance in a neotropical forest catchment of southeastern Brazil

Brazilian Atlantic Forest is recognized by the UNESCO as one of the most important biosphere reserves on the planet but is threatened by extinction. The objective of this study was to analyze the main components of the water balance in an Atlantic Forest (Neotropical Forest) catchment in the Mantiqueira Range, Brazil, which is a Tropical Montane Cloud Forest. The main focuses was to analyze baseflow, evapotranspiration, soil moisture, and canopy rainfall interception to understand the hydrologic dynamics in this specially important montane forest. On average from the two studied hydrological years (2009/2010 and 2010/2011), evapotranspiration (ET), streamflow (SF), and water storage in the catchment at the end of hydrological year corresponded, respectively, to 50%, 34.8% and 15.2% of total gross precipitation (P). On average, baseflow corresponded to 73.5% of SF. The estimated potential groundwater recharge during the wet seasons was 403.8 mm (21.7% of P observed in the wet season) and 710.5 mm (28.5% of P observed in the wet season), respectively, for 2009/2010 and 2010/2011 hydrological years, showing that the catchment is able to store groundwater to provide the maintenance of the streamflow during early recessions and drought periods. Therefore, the baseflow is important in mountainous catchments in the tropical regions to provide important ecological functions, mainly as freshwater reserve.

Evaluation of canopy rainfall interception by three broad-leaved spices in urban area

Evaluation of canopy rainfall interception by three broad-leaved spices in urban area

Importance of transitional leaf states in canopy rainfall partitioning dynamics

The temporal dynamics of forest canopy rainfall partitioning are important to forest ecology and management as it influences all subsequent hydrological processes along the rainfall-to-discharge flow path. Despite a growing body of literature on the importance of coupled hydrological–ecological interactions during periodic forest life cycle events, little work has examined how canopy rainfall partitioning varies across transitional leaf states (between the leafed vs. leafless states). This study analyzed a 3 year field monitoring campaign for two tree species in semiarid Iran (Robinia pseudoacacia and Platanus orientalis) to describe rainfall partitioning dynamics across the full-leaf, senescence, leafless, and leafing states. Crown saturation point, canopy storage capacity, free throughfall coefficient and the ratio of wet canopy evaporation rate to mean rainfall intensity were related to decreases/increases in plant area index and canopy closure. The high variability of rainfall partitioning observed in this study highlights the importance of transitional leaf states in the temporal characterization of water inputs to forest surfaces and boundary layer.

Effects of rainfall and vegetation to soil water input and output processes in the Mu Us Sandy Land, northwest China

Soil water plays a critical role in vegetation growth and restoration in semiarid regions, and has highly spatiotemporal variability. Gaining a comprehensive understanding of the soil water input and output processes is critical to the study of the hydrological cycle. To further unveil and quantify soil water dynamics, we embarked on a research program to quantify hydrological processes under three sites (i.e., shifting dune, shrub-dominated community, and herb-dominated community) with continuously monitored soil water content at 10-min intervals in the Mu Us Sandy Land between April and October 2012. The results indicated that soil water input and output processes were strongly affected by rainfall infiltration and surface characteristics. Rainfall affects the fluctuation of soil water content in deeper layers (60–80cm) by altering rainfall amount and soil texture; vegetation affects the soil water input process by altering the canopy rainfall interception, hydraulic lift, and soil organic matter content and so on. The effects of rainfall on the soil water output process mainly contributed to direct leakage and evaporation. Plant root distribution was a vital factor affecting the soil water output process. In addition, a state of dynamic equilibrium existed between the absorption of soil water and non-rainfall replenishment of soil water content during the output process over a long period of time. With limited soil water input and relatively larger soil water uptake by deeper roots, the soil water varied up to ~80% under the herb-dominated community. Our results imply that the increment of the deeper layer (60–80cm) would enhance shrub expansion in the Mu Us Sandy Land of China.

Predicted models for potential canopy rainfall interception capacity of landscape trees in Shanghai, China

This study aimed to build urban green space with environmental functions (e.g., canopy interception of rainfall) and adjust hydrographic balance to some extent for forecasting the potential canopy rainfall interception capacity of landscape trees and the effects on rainfall distribution. The effects of urban green space on interception and runoff reduction have been conceptualized, but not quantified. Therefore, the leaf area index and the water storage abilities of 17 kinds of landscape trees in common use were measured, at Shanghai, and canopy rainfall interception capacity was calculated using the interception formula. The predicted rainfall interception capacity models were established choosing tree morphological characteristics (diameter at the breast height, height, and crown width) as variables. The model test showed that the errors of 12 models were less than 5% between the predicted and the measured data and the errors of four models were within 5 and 10%, with the error for only one model being between 10 and 11%. Also, the study indicated that conifer trees were able to hold more rainfall compared with broad-leaved trees per unit area (k). The results showed that these models could effectively predict the potential capacity of canopy rainfall interception for landscape trees in Shanghai area and were beneficial for species selection in constructing plant communities, aiming to improve the rainfall interception capacity of urban green space.

Assessment of Water Use in Pan-Eurasian and African Continents by ETMonitor with Multi-Source Satellite Data

The Pan-Eurasian and African Continents are characterized by large ranges of climates varying from humid, semi-humid, semi-arid and arid regions, and great challenges exist in water allocation for different sectors that related to water resource and food security, which depends strongly on the water use information. Quantitative information on water use is also important to understand the effectiveness of water allocation and further to prevent from water stress resulted by drought in water-scarce regions. Explosive development of satellite remote sensing observations provide great chance to provide useful spatiotemporal information for quantifying the water use at regional to global scales. In this paper, a process-based model ETMonitor was used in combination with biophysical and hydrological parameters retrieved from earth observations to estimate the actual evapotranspiration, i.e. the agricultural and ecological water use. The total water use is also partitioned into beneficial part, e.g. plant transpiration, and non-beneficial part, e.g. soil evaporation and canopy rainfall interception, according to the water accounting framework. The estimated water use show good agreements with the ground observation, indicating the ability of ETMonitor for global and continental scale water use estimation. The spatial and temporal patterns of the water use in the Pan-Eurasian and African Continents were further analysed, while large spatial variation of water use was convinced. Current study also highlights the great capability of satellite observations in studying the regional water resource and continental water cycle.

Modeling Rainfall Interception Loss for an Epiphyte-Laden Quercus virginiana Forest Using Reformulated Static- and Variable-Storage Gash Analytical Models

AbstractBarrier island forests are sensitive to changing precipitation characteristics as they typically rely on a precipitation-fed freshwater lens. Understanding and predicting significant rainfall losses is, therefore, critical to the prediction and management of hydrometeorological processes in the barrier island forest ecosystem. This study measures and models one such loss, canopy rainfall interception, for a barrier island forest common across subtropical and tropical coastlines: epiphyte-laden Quercus virginiana on St. Catherine’s Island (Georgia, United States). Reformulated Gash analytical models (RGAMs) relying on static- and variable-canopy-storage formulations were parameterized using common maximum water storage (minimum, mean, maximum, and laboratory submersion) and evaporation (Penman–Monteith, saturated rain–throughfall regression, and rain–interception regression) estimation methods. Cumulative interception loss was 37% of rainfall, and the epiphyte community contribution to interception loss was 11%. Variable-storage RGAMs using inferred evaporation and maximum water storage estimates performed best: mean absolute error of 1–2 mm, normalized mean percent error of 15%–25%, and model efficiency of 0.88–0.97, resulting in a 2%–5% overestimate of cumulative interception. Static- and variable-storage RGAMs using physically derived evaporation (Penman–Monteith) underestimated observed interception loss (40%–60%), yet the error was significantly lowered for submersion estimates of maximum water storage. Greater apparent error when using Penman–Monteith rates may result from unknown drying times, evaporation sources, and/or in situ epiphyte storage dynamics. As such, it is suggested that future research apply existing technologies to quantify evaporative processes during rainfall (e.g., eddy covariance) and to develop new methods to directly monitor in situ epiphyte water storage.

Canopy Rainfall Interception Measured over Ten Years in a Coastal Plain Loblolly Pine (Pinus taeda L.) Plantation

<abstract> <b><sc>Abstract.</sc></b> The area of planted pine in the southern U.S. is predicted to increase by over 70% by 2060, potentially altering the natural hydrologic cycle and water balance at multiple scales. To better account for potential shifts in water yield, land managers and resource planners must accurately quantify water budgets from the stand to the regional scale. The amount of precipitation as rainfall intercepted by forest canopies is an important component of evapotranspiration in forested ecosystems, yet there is little information about intra- and inter-annual canopy interception variability in southern pine plantations. To address this knowledge gap, canopy rainfall interception was measured between 2005 and 2014 in a North Carolina coastal plain loblolly pine ( L.) plantation to quantify the range of annual and seasonal variability in interception rates (IRs) as influenced by stand thinning and natural variation in rainfall rates and intensities. Over the study period, biweekly measured canopy IRs averaged 19% across all years, with a range of 14% to 23%. However, at the annual scale, IRs averaged 12% and ranged from 2% to 17%. Thinning resulted in a 5% decrease in rainfall interception, but IRs quickly returned to pre-thin levels. Across years, the amount of annual rainfall intercepted by the canopy averaged 15% of total evapotranspiration, with a range of 2% to 24%. The decade-long data indicate that inter-annual variability of canopy interception is higher than reported in short-term studies. Local and regional hydrological models must describe the variability of canopy interception to accurately predict the hydrologic impacts of forest management and climate change.

Canopy Rainfall Intercepted by Nineteen Tree Species Grown on a Phytocapped Landfill

“Phytocapping” is an alternative landfill capping technique that consists of two components, viz. soil cover and vegetation. The soil cover stores water during rainfall events and the vegetation; in this study, trees remove stored water via transpiration and reduce the amount of rain reaching the ground surface via canopy rainfall interception. These attributes contribute significantly to hydrological balance of the phytocap thereby preventing rainwater from entering the buried waste. Canopy rainfall interception was studied for the first time in 19 tree species grown in a landfill environment. Various parameters contributing to canopy interception were monitored over 2 years using 19 tree species that were established on two types of phytocaps (Thick cap 1400 mm soil and Thin cap 700 mm soil). Stemflow and throughfall were determined during 50 rainfall events over two years. Results showed that the established species were able to intercept up to 50% of the rainfall on a per storm basis, with an overall average of 30%. Stemflow also varied between species, but its overall contribution to site water balance was only 4.5% of the total rainfall received.

Rainfall interception and the coupled surface water and energy balance

Evaporation from wet canopies (E) can return up to half of incident rainfall back into the atmosphere and is a major cause of the difference in water use between forests and short vegetation. Canopy water budget measurements often suggest values of E during rainfall that are several times greater than those predicted from Penman–Monteith theory. Our literature review identified potential issues with both estimation approaches, producing several hypotheses that were tested using micrometeorological observations from 128 FLUXNET sites world-wide. The analysis shows that FLUXNET eddy-covariance measurements tend to provide unreliable measurements of E during rainfall. However, the other micrometeorological FLUXNET observations do provide clues as to why conventional Penman–Monteith applications underestimate E. Aerodynamic exchange rather than radiation often drives E during rainfall, and hence errors in air humidity measurement and aerodynamic conductance calculation have considerable impact. Furthermore, evaporative cooling promotes a downwards heat flux from the air aloft as well as from the biomass and soil; energy sources that are not always considered. Accounting for these factors leads to E estimates and modelled interception losses that are considerably higher. On the other hand, canopy water budget measurements can lead to overestimates of E due to spatial sampling errors in throughfall and stemflow, underestimation of canopy rainfall storage capacity, and incorrect calculation of rainfall duration. There are remaining questions relating to horizontal advection from nearby dry areas, infrequent large-scale turbulence under stable atmospheric conditions, and the possible mechanical removal of splash droplets by such eddies. These questions have implications for catchment hydrology, rainfall recycling, land surface modelling, and the interpretation of eddy-covariance measurements.

Isotopic and nutritional evidence for species‐ and site‐specific responses to N deposition and elevated CO2 in temperate forests

AbstractIn this study we show that the effect of rising atmospheric CO2 levels on forest productivity is influenced by changes in nutrient availability caused by nitrogen (N) deposition. We used a dual‐isotope approach (δ15N and δ13C), combined with dendrochronological and nutritional analyses, to evaluate the response of two dominant tree species in natural forest ecosystems near Mexico City (Pinus hartwegii—pine; Abies religiosa—fir). Our analysis focuses on changes that occurred over the past 50 years at two sites, one under high and one under low N deposition rates. Analyses of carbon isotope composition indicate increasing water‐use efficiency in response to rising CO2 levels for both species and sites but this effect did not lead to improved tree growth. The magnitude and direction of shifts in 13C discrimination indicate a process of acclimation that varied with the rate of N deposition and species traits. Since the 1960s, strong negative responses to N deposition have been observed in fir trees, which showed altered foliar nutrition and growth decline, while the negative impacts of N deposition on pine trees remained undetectable until the 1990s. In recent years, both species have shown significant growth decline under high N deposition despite increasing atmospheric CO2. Multivariate analysis of leaf nutrients indicates that growth decline was prompted by depleted soil macronutrient (P, K, and Ca) and micronutrient (Cu, Fe, Zn, and Mn) availability. At both sites, fir trees were a better indicator of N deposition due to differences in canopy rainfall interception.

First attempt to measure rainfall canopy interception loss, throughfall, and stemflow in Juglans regia Linn and Cup. Sempervirens L. Var. fastigiata in the north of Iran

Each individual tree significantly alters the growth of surrounding vegetation by partitioning of rainfall and nutrients to the rooting zone. The Iranian Hyrcanian forests are among one of the most fragile ecosystems of the country owing to large industrial activities for logging and extensive urbanisation. These may accelerate disturbing of this unique type of forest. Of concern currently is an increase in plantations of Juglans regia Linn and a Cup. Sempervirens L. Var. fastigiata species, which has taken place over the past few decades for agro–forestry and ornamental purposes. As such it has the potential to affect the growth of associated vegetation by altering the hydrological balance within this region. The results indicate that walnut trees are at the range of interception of temperate forest trees whereas cypress trees have a very high amount of interception. Thus, care should be taken in planting cypress trees over a vast area.

Forest Canopy Interception Loss Across Temporal Scales: Implications for Urban Greening Initiatives

Increasing urban forest canopy coverage due to greening initiatives requires watershed managers to balance societal water practices with forest hydrological processes. One such process, canopy rainfall interception, can remove substantial portions of precipitation from catchments by simply intercepting, storing, and evaporating meteoric water. We performed a field study examining interception losses across temporal scales comparing two landscaping species of contrasting crown structures (Fagus grandifolia Ehrh., American beech, and Liriodendron tulipifera L., yellow poplar), native to the highly urbanized northeastern United States, to highlight the effect of landscape design on urban water and storm water management. Results show that landscape designs using the rougher bark texture, lower branch inclination, and thinner canopy of L. tulipifera can increase water losses during rainfall and, therefore, can be used to improve storm water management. On the other hand, the smoother bark, higher branch inclination, and deeper canopy of F. grandifolia decreased water losses, allowing greater water transfer to the surface or subsurface. Thus, interception-related water resource losses during urban forestry projects can be manipulated to benefit urban sustainability efforts if designers consider the multifaceted ramifications of planting different tree species with differing canopy structures.

The role of the residential urban forest in regulating throughfall: A case study in Raleigh, North Carolina, USA

Overwhelming stormwater volumes, associated with deteriorating water quality and severe flooding in urbanizing cities, have become a great environmental and financial concern globally. Urban forests are capable of reducing the amount of stormwater runoff, in part, by regulating throughfall via canopy rainfall interception; however, the lack of stand-scale studies of urban throughfall hinders realistic estimates of the benefits of urban vegetation for stormwater regulation. Furthermore, urban forest characteristics that may be influencing rainfall interception are difficult to establish as these environments are extremely heterogeneous and managed, to a large extent, by private residents with varying landscape preferences. To quantify the amount of rainfall interception by vegetation in a residential urban forest we measured throughfall in Raleigh, NC, USA between July and November 2010. We analyzed 16 residential yards with varying vegetation structure to evaluate the relative importance of different descriptive measures of vegetation in influencing throughfall in an urban watershed. Throughfall comprised 78.1–88.9% of gross precipitation, indicating 9.1–21.4% rainfall interception. Canopy cover (p<0.0001) and coniferous trees (p=0.017) were the most influential vegetation variables explaining throughfall whereas variables such as leaf area index were not found significant in our models. Throughfall and vegetation characteristics varied significantly among yards (p<0.0001), between front and back yards (p<0.0001), and between rented and privately-owned yards (p=0.001), suggesting a potentially significant role in stormwater regulation for urban residents.

Erratum—Canopy Rainfall Interception and Fog Capture by Pinus pumila Regal at Mt. Tateyama in the Northern Japan Alps, Japan

Erratum—Canopy Rainfall Interception and Fog Capture by Pinus pumila Regal at Mt. Tateyama in the Northern Japan Alps, Japan

Canopy Rainfall Interception and Fog Capture by Pinus pumila Regal at Mt. Tateyama in the Northern Japan Alps, Japan

The importance of fog precipitation in the alpine hydrological processes of Pinus pumila canopy was evaluated on Mt. Tateyama, central Japan. We observed rain and fog precipitation, throughfall, and wind direction and velocity at Jodo-daira (36.566°N, 137.606°E, 2840 m a.s.l.) for 3 years. During the snow-free period (August and September), mean monthly rain and fog precipitation was 0.45 mm h−1 and 0.14 mm h−1, respectively. The mean rainfall interception by P. pumila canopy was about 48%, which is higher than that of other forest canopies at lower altitudes. During rainfall, the dense canopy intercepts rain and the water evaporates from the needle surfaces. On the other hand, the canopy captured fog precipitation even in the absence of rainfall. The amount of throughfall increased with increasing fog deposition. Using δ18O and δD analysis, the mean contribution of fog water to the throughfall was estimated at approximately 35%, consistent with the result from direct measurement. These results indicate that P. pumila should have a significant influence on the local hydrological processes of the high mountain ecosystem. The large contribution of fog precipitation can be attributed to the high wind velocity and humidity of the Japan Alps.

Simulation of Rainfall Interception of Canopy and Litter in Eucalyptus Plantation in Tropical Climate

The interception of rainfall by vegetation is an important process in the hydrological cycle and has been the subject of research for several decades. Researchers have intensified investigations of the contribution of the water balance components in eucalyptus productivity. There are few reports of modeling canopy and litter rainfall interception in eucalyptus plantations. The objectives of this work were to measure and to simulate canopy and litter rainfall interception in an eucalyptus plantation located in a tropical climate area. The Rutter model was used for simulating the canopy rainfall interception, and the tank model was applied for simulating the litter rainfall interception. The estimated interception values were compared with measured values. The results showed that the maximum accumulated difference between the measured canopy rainfall interception and that estimated by the Rutter model was 6.2 mm, corresponding to 1.1% of the gross rainfall. The litter rainfall interception presented a maximum accumulated difference between the measured and estimated values of 0.8 mm, equivalent to 0.2% of the gross rainfall. The Rutter and tank models were efficient for simulating canopy and litter rainfall interception, respectively, for eucalyptus plantations in the tropical study area.

Canopy rainfall storage capacity as affected by sub‐alpine grassland degradation in the Qinghai–Tibetan Plateau, China

AbstractGrassland degradation resulting from global climate change, overgrazing, and rodent damage is expected to influence the magnitude of canopy hydrological fluxes because of reduced vegetation biomass and changed species composition. The objectives of this study were to estimate herbaceous canopy rainfall storage capacity (S) along three different stages of sub‐alpine grassland degradation (non‐degraded, lightly degraded and moderately degraded) in the Qinghai–Tibetan Plateau, China, and relate changes in S to canopy properties. An artificial wetting method and the water budget balance method, using rain simulations, were used for estimating S. Grassland degradation significantly reduced S. In non‐degraded, lightly degraded and moderately degraded grasslands, S estimated using the artificial wetting method were 0.612 ± 0.08 mm, 0.289 ± 0.04 mm, and 0.217 ± 0.01 mm, respectively; S estimated using the water budget balance method were 0.979 ± 0.32 mm, 0.493 ± 0.13 mm, and 0.419 ± 0.09 mm, respectively. These changes could be explained by accompanying changes in above‐ground biomass and leaf area index, as well as changes in species composition. Species‐specific rainfall storage capacity varied by a factor of 2.7 among the investigated species, with graminoids having the lowest values. Leaf area index was more correlated to S than was canopy coverage. Converting fresh weight of non‐leaf tissues into effective leaf area of the corresponding species and then introducing a coefficient of leaf area according to the specific storage capacity of leaves improved the linear relationship between S and leaf area index. Copyright © 2011 John Wiley &amp; Sons, Ltd.

Global and regional coupled climate sensitivity to the parameterization of rainfall interception

A coupled land–atmosphere model is used to explore the impact of seven commonly used canopy rainfall interception schemes on the simulated climate. Multiple 30-year simulations are conducted for each of the seven methods and results are analyzed in terms of the mean climatology and the probability density functions (PDFs) of key variables based on daily data. Results show that the method used for canopy interception strongly affects how rainfall is partitioned between canopy evaporation and throughfall. However, the impact on total evaporation is much smaller, and the impact on rainfall and air temperature is negligible. Similarly, the PDFs of canopy evaporation and transpiration for six selected regions are strongly affected by the method used for canopy interception, but the impact on total evaporation, temperature and precipitation is negligible. Our results show that the parameterization of rainfall interception is important to the surface hydrometeorology, but the seven interception parameterizations examined here do not cause a statistically significant impact on the climate of the coupled model. We suggest that broad scale climatological differences between coupled climate models are not likely the result of how interception is parameterized. This conclusion is inconsistent with inferences derived from earlier uncoupled simulations, or simulations using very simplified climate models.