Canopy Rainfall Interception Research Articles

On Canopy Rainfall Interception Modeling in a Eucalyptus Plantation

The interaction between the forest canopy and precipitation is a fundamental process for understanding the hydrological cycle in forests. Physical models have been applied to estimate canopy water interception, and their efficiency has been tested based on metrics used to assess hydrological models. For eucalyptus plantations in Brazil, more studies are needed on the canopy rainfall interception model. Thus, we calibrated the Gash model using two complete hydrological years of observation in a eucalyptus plantation in southeastern Brazil. The model’s parametrization was conducted using 17 trees individually in different planting spacings (3 m × 2 m, 3 m × 3 m, and 3 m × 5 m). The average values of the model’s parameters were taken to represent the forest, and the average parameters for each planting spacing were used to assess the model’s performance according to the planting spacings. We used NSE, KGE, and Pbias statistical metrics to assess the model’s performance. For individual trees and rainfall events, the model showed an average NSE and Pbias of 0.59 and 18.2%, respectively, meaning a “satisfactory” performance for eight trees and “poor” performance for nine trees. When the model was averaged for the entire forest and individual rainfall events were considered, the metrics were improved, being 0.643 for NSE and 8.2% for Pbias, indicating a “good” model performance, which was strengthened by an average KGE of 0.746. Regarding the model for the planting spacings, the best results were found for the 3.0 m × 2.0 m spacing (“a good performance”). For the other spacings, Pbias was higher than 15%, leading to inferior performance, but with the NSE and KGE compatible with “good” performance. The practical implications of our findings are significant, as they can be used to enhance the accuracy of models for a better understanding of the hydrological cycle in eucalyptus forests in Brazil, thereby contributing to more effective forest management and conservation.

Forest cover lessens hurricane impacts on peak streamflow

AbstractCyclonic storms (i.e., hurricanes) are powerful disturbance events that often cause widespread forest damage. Storm‐related canopy damage reduces rainfall interception and evapotranspiration, but impacts on streamflow regimes are poorly understood. We quantify streamflow changes in Puerto Rico following Hurricane Maria in September 2017, and evaluate whether forest cover and storm‐related canopy damage account for the differences. Streams are particularly vulnerable to flooding in early post‐disturbance stages during hurricane season, so we focus on 3 months (Oct–Dec) following the hurricane. To discern changes in rainfall responses, we partitioned streamflow into baseflow and quickflow using a digital filter. We collected 2010–2017 streamflow and rainfall data from 18 watersheds and compared the relative magnitude of post‐ to pre‐hurricane double mass curve slopes of baseflow and quickflow volumes against rainfall. Several watersheds displayed higher post‐hurricane quickflow and baseflow, however, the response was variable. The magnitude of quickflow increase was greater in watersheds with high forest damage. Under the same level of relative damage, watersheds with low initial forest cover had greater quickflow increases than highly forested ones. Conversely, baseflow generally increased, but increases were greater in highly forested watersheds and smaller in highly damaged watersheds. These results suggest that post‐storm baseflow increases were due to recharge of hurricane‐related rainfall, as well as forest transpiration interruption and soil disturbance enhancing recharge of post‐hurricane rainfall, while increases to quickflow are related to loss of canopy rainfall interception and higher soil saturation decreasing infiltration. Our research demonstrates that forest damage from disturbance lowers quickflow and elevates baseflow in highly forested watersheds, and elevates quickflow and lowers baseflow in less‐forested watersheds. Less‐forested watersheds may be closer to the forest cover loss threshold needed to elicit a streamflow response following disturbance, suggesting higher flooding potential downstream, and a lower storm‐related forest disturbance threshold than in heavily forested watersheds.

Aboveground biomass determines canopy rainfall interception loss in Semiarid Grassland Communities

AbstractCanopy rainfall interception is one key hydrological process, affecting rainwater redistribution and effectiveness in semiarid regions. Canopy rainfall interception loss is jointly influenced by meteorology, vegetation and topography. The canopy water storage capacity (S), rainfall interception depth (Im) and ratio (I%) and vegetation characteristics, together with topographic factors of three grassland communities (dominated by Bothriochloa ischaemum, Lespedeza davurica and Artemisia gmelinii, respectively) were investigated on the Loess Plateau of China during the main growing season (June to September). Results showed that Im ranged from 0.55 to 0.89 mm and I% ranged from 6.14% to 12.1%, with the maximum values occurring in August for three communities, and A. gmelinii community had the largest Im (0.89 mm) and I% (12.1%). The Im and I% were positively correlated with aboveground biomass (AGB), coverage (Cov), leaf area index (LAI), community‐weighted mean height (CWMH) and altitude (Alt), but negatively correlated with slope degree and rainfall intensity (RI). Hierarchical partitioning analysis (HPA) showed that AGB had the highest contribution for Im (20.3%), while Alt had the highest contribution for I% (18.2%). The regression models based on forward selection could effectively predict the values of Im (R2 = 0.802, RMSE = 0.049) and I% (R2 = 0.546, RMSE = 1.434). Topographic factors (altitude, slope degree and aspect) indirectly influenced both Im and I% by modulating vegetation characteristics (AGB, Cov, etc.). All these indicated that aboveground biomass mainly determines grassland community rainfall interception loss in the semiarid Loess Plateau.

Deciphering global patterns of forest canopy rainfall interception (FCRI): A synthesis of geographical, forest species, and methodological influences

Forest canopy rainfall interception (FRCI) is an essential hydrological process that governs water and biogeochemical cycles in forest ecosystems. Identifying patterns and relationships of FCRI using a systematic review is key to improving our knowledge supporting new experiment research, modeling, and application. In this meta-analysis, we aimed to delineate the canopy interception (CI), throughfall (TF), and stemflow (SF) concerning geographical and forest variables and experimental methodologies. We leveraged peer-reviewed 170 articles across 234 sites globally, extracting TF, CI, SF, geographical, forest, and experimental aspects. We applied multivariate statistical procedures to discern the principal influences on TF, CI, and SF and examined their multicollinearity. In addition, we developed Generalized Linear Models (GLM) for CI and TF. Global TF experiments indicate that the predominant rainfall devices, number of sample trees, number of events, and monitoring length are 10–20 devices (81% fixed), 3–6 trees, 30–50 events, and 10–30 months. Predominant global values of TF, CI, and SF are 70–80% (median = 73%), 20%–30% (median = 23.9%), and <1.0% (median = 1.87%), respectively. Global models of CI and TF were responsive to T, LAI, and D (respectively, R2adj of 0.196** and 0.206**). Temperate forests mirrored the global model (R2adj of 0.274** and 0.31**, respectively). The Subtropical CI model was fitted based on P and DBH (R2adj = 0.245*), and the TF model was based on E, D, and LAI (R2adj = 0.532**); the Mediterranean CI model was based on T, Basal, and LAI (R2adj = 0.45*), while TF was based on P, Basal, and LAI (R2adj = 0.671**). The Tropical CI model was based on T and H (R2adj = 0.396*), and the TF model, LAI, and P (R2adj = 0.35*). This meta-analysis underscores the importance of comprehending the hydrological processes in forested areas as they are pivotal in mitigating climate change impacts.

Canopy rainfall interception by pine (Pinus hartwegii Lindl) and oyamel [Abies religiosa ( Kunth ) Schltdl. y Cham.] at the Zoquiapan Experimental Forest Station, Mexico

Objective: To quantify and characterize the canopy rainfall interception of twodominant forest species of a coniferous forest in Mexico, in order to determine its magnitude and importance in the hydrological cycle and have a source of estimation of interception to improve the accuracy of water balance calculation.Methodology: Twenty-one rainfall events in the period May-June 2018 were analyzed in two 0.25-ha experimental plots, one with pine (Pinus hartwegii) and theother with oyamel (Abies religiosa), at the Zoquiapan Experimental Forest Station (EFEZ), located in the Sierra Nevada in the State of Mexico. Rainfall was measured with an automated weather station and interception was recorded by placing collectors under the canopy and collars on the trunks.Results: The pine tree P. hartwegii intercepted 16.37% of the precipitation, 79.86% of the throughfall, and 3.74% of the stemflow. For A. religiosa, recorded interception was 24.68%, throughfall 72.42%, and stemflow 2.90%. Precipitation had a linear relationship with both throughfall and stemflow, and an exponential one with canopy rainfall interception.Implications: The analysis should be extended to other rainy periods to strengthen the study.Conclusions: The intercepted volume depends on the forest measurement characteristics and leaf area index (LAI) of the species, and the rainfall amount. The fraction of rainfall intercepted is considerable and should be included in hydrological balances.

Global land surface evapotranspiration monitoring by ETMonitor model driven by multi-source satellite earth observations

Evapotranspiration (ET) is an essential ecohydrological process linking the land surface energy, water and carbon cycles, and plays a critical role in the earth system. ET remains one of the most problematic components of the water cycle to be determined due to the heterogeneity of the landscape and the complexity of driving factors. The satellite-based earth observation is expected to provide ET information at large-scales. However, accurate global ET information, with spatially and temporally continuous coverage at moderate-to-high resolution, is still scarce. In this paper, a combined model, called ETMonitor, with multi-process parameterizations, was improved and applied to estimate the global ET, mainly using the biophysical and hydrological parameters/variables retrieved from satellite observations. The ETMonitor model was improved in several aspects in this study to generate the global ET datasets during 2000–2019 at daily/1-km resolution, including: 1) adopting high temporal resolution surface water cover and snow/ice cover as input, to simulate the impact of their seasonal change on ET variation; 2) parameterizing the impact of soil moisture on plant transpiration and soil evaporation using high resolution soil moisture, which was downscaled to 1-km resolution from the coarse resolution data retrieved from microwave remote sensing observation; 3) involving a better soil heat flux estimation to reduce its impact on the uncertainty of estimated ET; 4) being calibrated based on global ground flux observations to achieve better accuracy. The estimated daily ET was validated based on the global in situ observations at site scale across various ecosystems, with overall high correlation (0.75), low bias (0.08 mm d-1), and low root mean square error (0.93 mm d-1). It had good ability to partition total ET to plant transpiration and soil evaporation indicated by the good agreement with the ground isotope measurements in a growing season at one site in the northwest China. The estimated global ET was cross-validated by comparing with other existing ET products, and it showed the global ET estimated by ETMonitor could capture the expected global ET patterns both in space and in time. It also indicated the superiority of the ET product by ETMonitor in the following aspects: capability in capturing the seasonal dynamics of waterbody evaporation and sublimation; better performance in capturing the spatial variation of ET in the irrigated cropland regions and mountain regions with complex terrain than other global ET products, e.g., the GLEAM and MOD16 ET products; capability of ET component partitioning at high spatial (1-km) and high temporal (daily) resolutions with good accuracy. The estimated plant transpiration, soil evaporation, canopy rainfall interception loss, and water body evaporation and snow sublimation accounted for 61.54 % (±0.44 %), 19.08 % (±0.54 %), 13.54 % (±0.49 %), and 5.84 % (±0.24 %), respectively, of the total ET on global average. The ETMonitor global ET dataset could provide important information on studies of global terrestrial water and energy cycles and climate change studies, and water resources management at global and regional scales.

Leaf water absorption and canopy rainfall interception of twenty-one plant species in Beijing

Leaf water absorption and canopy rainfall interception of twenty-one plant species in Beijing

Long-term investigation of forest canopy rainfall interception for a spruce stand

The factors influencing the interception process such as the vegetation structure and the meteorological conditions, especially rainfall characteristics, are diverse and highly variable. Therefore, derivation of canopy parameters for interception modelling requires data from field experiments over a long period. In this study, we analyse long-term changes in canopy parameters and rainfall interception for an old-growth spruce stand (composed mainly of Picea abies at a continuous flux site started within EUROFLUX in 1996) within the Tharandter Wald, Southwest of Dresden, Germany. The 10-minute data from the continuous measurements of gross precipitation (P) and throughfall (TF) from 1997 to 2018 were used as follows: Rainfall events were separated by a minimum time of three hours without rainfall and divided into rainfall classes according to their total amount and intensity. Due to vegetation changes in the measuring period caused by two thinning operations, the complete study period was divided into three periods. Canopy parameters S (storage capacity), p (free throughfall coefficient) and Ps (canopy saturation point) were then generated applying a regression-based method using the relationship between P and TF. We generated parameter sets for the complete period, for the three periods reflecting the vegetation changes and for single years. These parameter sets were further tested using a regression model.The statistical analysis of the long-term data set showed that stand parameters and interception are largely influenced by vegetation changes. S and Ps decreased with each thinning. Interestingly, interception and rainfall only changed after the first thinning (increase in p, decrease in interception), indicating counter-acting factors after the second thinning, such as changes in meteorological conditions, rainfall patterns or thinning induced changes in the microclimate of the canopy.Generally, the reliability of the derived canopy parameters depends on the length of the dataset used for the regression analysis. However, the parameter sets that considered three periods produced the best model fit compared to parameter sets for the complete period or for single years. This clearly shows that model performance of statistical interception models depend on a reliable parameterisation that can be improved when taking into account changes in stand characteristics.

Global canopy rainfall interception loss derived from satellite earth observations

AbstractInformation on global canopy rainfall interception loss is essential for understanding the dynamics of land surface processes and the water cycle. In addition, large uncertainty remains regarding the global variation in this factor. The development of satellite earth observations has provided a great opportunity for the estimation of global rainfall interception loss to reveal the spatiotemporal variations. In the current study, the analytical Gash model was adapted and applied to estimate global rainfall interception loss from 2001 to 2015 on the basis of satellite remote‐sensing products, for example, gross rainfall amount and rate and leaf area index. The Dalton‐type equation was adopted to estimate the wet canopy evaporation rate in the revised Gash model. The estimation on the basis of the Dalton‐type equation showed better agreement with the ground observations than the classical Penman–Monteith equation in terms of estimated rainfall interception loss and its ratio to gross rainfall. Large spatial variations in global rainfall interception loss were found, and high values appeared in the regions with dense vegetation cover and high gross rainfall amounts, for example, tropical rainforests, whereas high rainfall interception to gross rainfall ratios occurred in the regions with low rain rates and high vegetation cover. This study constitutes a significant step forward in understanding global hydrological cycle on the basis of earth observation products.

Estimating Rainfall Interception of Vegetation Canopy from MODIS Imageries in Southern China

The interception of rainfall by vegetation canopies plays an important role in the hydrologic process of ecosystems. Most estimates of canopy rainfall interception in present studies are mainly through field observations at the plot region. However, it is difficult, yet important, to map the regional rainfall interception by vegetation canopy at a larger scale, especially in the southern rainy areas of China. To obtain a better understanding of the spatiotemporal variation of vegetation canopy rainfall interception with regard to the basin scale in this region, we extended a rainfall interception model by combining the observed rainfall data and moderate resolution imaging spectroradiometer leaf area index (MODIS_LAI) data to quantitatively estimate the vegetation canopy rainfall interception rate (CRIR) at small/medium basin scales in Guangdong Province, which is undergoing large changes in vegetation cover due to rapid urban expansion in the area. The results showed that the CRIR in Guangdong declined continuously during 2004–2012, but increased slightly in 2016, and the spatial variability of CRIR showed a diminishing yearly trend. The CRIR also exhibited a distinctive spatial pattern, with a higher rate to the east and west of the mountainous areas and a lower rate in the central mountainous and coastal areas. This pattern was more closely related to the spatial variation of the LAI than that of rainfall due to frequent extreme rainfall events saturating vegetation leaves. Further analysis demonstrated that forest coverage, instead of background climate, has a certain impact on the canopy rainfall interception, especially the proportion of broad-leaved forests in the basin, but more in-depth study is warranted in the future. In conclusion, the results of this study provide insights into the spatiotemporal variation of canopy rainfall interception at the basin scale of the Guangdong Province, and suggest that forest cover should be increased by adjusting the species composition to increase the proportion of native broad-leaved species based on the local condition within the basin. In addition, these results would be helpful in accurately assessing the impacts of forest ecosystems on regional water cycling, and provide scientific and practical implications for water resources management.

The effects of tree characteristics on rainfall interception in urban areas

Trees in urban areas have significant effects on the urban ecosystem. They can be used to improve the water cycle in urban areas by increasing evaporation and reducing runoff through rainfall interception. Street trees placed in planters on impervious areas reduce runoff by intercepting rainfall and by temporarily storing raindrops on leaves. Therefore, understanding tree canopy geometry and the effect of rainfall interception is important in urban hydrology. In this study, we assessed the effect of tree canopy morphology on rainfall interception using four major street tree species, Sophora japonica L., Ginkgo biloba L., Zelkova serrata (Thunb.) Makino, and Aesculus turbinata Blume, in Seoul, South Korea. We measured throughfall for each tree and also derived three-dimensional data of tree canopy morphology with a terrestrial laser scanner. Tree height, canopy crown width, leaf area index (LAI), leaf area density, mean leaf area, and mean leaf angle were used to determine canopy morphology. The interception rate was mostly affected by the LAI; a higher LAI tended to result in a higher interception rate. Leaf area affected the rainfall interception rate when trees had similar LAIs. These findings on individual tree canopy rainfall interception can help us to understand the importance of rainfall interception in hydrology and for ecological restoration when planning urban green spaces.

Influence of Rainfall on Canopy Interception in Mixed Broad-Leaved—Korean Pine Forest in Xiaoxing’an Mountains, Northeastern China

The mixed forest of broad-leaved and Korean pine is the dominant type in the Xiaoxing’an and Changbai Mountains of China. However, few studies have been done on its canopy interception of rainfall. In this study, rainfall amount, rainfall intensity, and canopy interception were monitored during the growing seasons in 2010 and 2011. The results showed that cumulative canopy interception of rainfall was 22.0% and 21.9% in 2010 and 2011, respectively. However, the canopy interception of rainfall varied with rainfall events from 6.6% to 82.7% in 2010, and from 8.7% to 80.2% in 2011. The relationship between rainfall amount and the ratio of canopy interception to rainfall amount could be described by a power function (P &lt; 0.01), i.e., the canopy interception decreased with the increasing rainfall amount and intensity. These results indicate that the rainfall amount and intensity were important factors for estimating the canopy interception of the studied forest type.

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

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.

Intrastorm scale rainfall interception dynamics in a mature coniferous forest stand

Canopy interception of rainfall is an important process in the water balance of forests. The intrastorm dynamics of canopy interception is less well understood than event scale interception. Accordingly, armed with measurements of hourly interception intensity (i) from the field, this study is among the first to examine the differences in canopy interception dynamics between the first and second halves of rainfall events to quantify dynamic storage values for a coniferous forest in Japan. At this site, experimental results demonstrated that: (1) the relationship between interception loss (I) and gross rainfall (GR) at the event scale is better explained by a parabolic curve than a linear relationship, and there is a low correlation between rainfall intensity (gr) and i; (2) the ratio of accumulated i during the first half (IF) to that of gr (GRF) was larger than the second half (IS/GRS), with no significant correlations between potential evaporation during first half (PEF) vs IF or the second half (PES) vs IS; and (3) water storage capacity was similar to the magnitude of maximum I. By emphasizing the comparison between IF and IS, this study concludes that the water storage on tree surface is more important than losses by wet canopy evaporation and splash during rain. This study also adds insights into intrastorm interception dynamics of coniferous forests which are necessary to better model and forecast interception losses.

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.