Agricultural and Forest Meteorology最新文献_第8页

Urbanization diminishes net ecosystem productivity by changing the landscape pattern 城市化通过改变景观格局降低了生态系统净生产力

IF 5.6 1区农林科学 Q1 AGRONOMY

Agricultural and Forest Meteorology

Pub Date : 2024-12-19 DOI: 10.1016/j.agrformet.2024.110369

Han Chen , Yizhao Wei , Jinhui Jeanne Huang

Urban net ecosystem productivity (NEP_u) plays a pivotal role in enhancing urban ecological conditions and human comfort in living environments. However, the response mechanism of NEP_u to urbanization remains unclear due to the challenge of accurately estimating NEP_u. This study proposes a hybrid model architecture that combines Residual Networks and Carnegie–Ames–Stanford approach (CASA) model (ResNets-CASA) to estimate NEP_u. The ResNets-CASA model is trained and verified at four urban eddy covariance (EC) sites in Tianjin and Shenzhen, China. The model shows an average root-mean-square-error (RMSE) of 1.09 gC/m²/day and a coefficient of determination (R²) of 0.83 for daily NEP_u simulation across the four EC sites. The trained ResNets-CASA model at the site scale is further employed for regional-scale NEP_u mapping and the generation of long-term historical NEP_u datasets (1986–2022) for the two cities. The long-term trend analysis indicates that the NEP_u of the two cities shows a significant downward trend over the past 37 years, with an average decline rate of 2.1 gC/m²/year across the two cities. The main cause for the decline trend of NEP_u is the changed urban landscape pattern, including: 1) a decrease in urban vegetation coverage resulting from urbanization; 2) shifts in the composition of urban vegetation species due to the substitution of natural woodland and cultivated land with urban landscape grassland. These results emphasize the dominant role of changes in urban landscape patterns, rather than urban microclimate, in the long-term decline of NEP_u trends.

城市生态系统净生产力（NEPu）在改善城市生态条件和人类居住环境舒适度方面具有重要作用。然而，由于难以准确估算NEPu， NEPu对城市化的响应机制尚不清楚。本研究提出了一种混合模型架构，结合残差网络和卡耐基-阿姆斯-斯坦福方法（CASA）模型（ResNets-CASA）来估计NEPu。ResNets-CASA模型在中国天津和深圳的四个城市涡动相关（EC）站点进行了训练和验证。该模型显示，四个EC站点每日NEPu模拟的平均均方根误差（RMSE）为1.09 gC/m2/day，决定系数（R2）为0.83。在站点尺度上训练的ResNets-CASA模型进一步用于区域尺度的NEPu制图和生成两个城市的长期历史NEPu数据集（1986-2022）。长期趋势分析表明，近37 a来，两市NEPu均呈现明显下降趋势，平均下降幅度为2.1 gC/m2/年。导致NEPu下降趋势的主要原因是城市景观格局的变化，包括：1)城市化导致的城市植被覆盖度下降；2)自然林地和耕地被城市景观草地取代，城市植被种类组成发生变化。这些结果强调了城市景观格局的变化在NEPu趋势的长期下降中起主导作用，而不是城市小气候。

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引用次数: 0

Spatial heterogeneity of tree-growth responses to climate across temperate forests in Northeast Asia 东北亚温带森林树木生长对气候响应的空间异质性

IF 5.6 1区农林科学 Q1 AGRONOMY

Agricultural and Forest Meteorology

Pub Date : 2024-12-18 DOI: 10.1016/j.agrformet.2024.110355

Nela Altmanová , Pavel Fibich , Jiří Doležal , Václav Bažant , Tomáš Černý , Julieta G. Arco Molina , Tsutomu Enoki , Toshihiko Hara , Kazuhiko Hoshizaki , Hideyuki Ida , Pavel Janda , Akira Kagawa , Martin Kopecký , Kirill A. Korznikov , Pavel V. Krestov , Yasuhiro Kubota , Vojtěch Lanta , Martin Macek , Marek Mejstřík , Masahiro Nakamura , Jan Altman

Ongoing climate change is having profound impacts on the growth and distribution of trees worldwide. However, there remain substantial gaps in our understanding of how environmental factors influence tree-growth responses to climate at larger scales, which is critical for identifying regions susceptible to the impacts of climate change. In this study, we aimed to reveal the main environmental factors that determine the spatial heterogeneity of tree-growth sensitivity to temperature, precipitation, and drought across temperate forests in Northeast Asia (30–45° N, 124–146° E). Utilising an extensive tree-ring network of 101 chronologies of 22 tree species, across 79 sites, we found that local climate, and especially climate water deficit, plays a dominant role in shaping the spatial heterogeneity of tree-growth sensitivity, while geospatial variables were less important. Our analysis revealed a pervasive pattern of increased tree susceptibility to drought across Northeast Asian forests. Specifically, at sites experiencing high climate water deficit, tree growth was consistently reduced across both broadleaved and coniferous species under conditions of low precipitation, elevated temperatures, and increased dryness during the growing season. Our findings suggest that ongoing climate warming may further negatively affect tree-growth performance, especially at drier sites, across Northeast Asian forests.

持续的气候变化正在对全球树木的生长和分布产生深远的影响。然而，我们对环境因素如何影响树木生长在更大尺度上对气候的响应的理解仍然存在很大的差距，这对于确定易受气候变化影响的区域至关重要。在本研究中，我们旨在揭示影响东北亚温带森林（30-45°N, 124-146°E）树木生长对温度、降水和干旱敏感性空间异质性的主要环境因子。利用覆盖79个站点的22种树种的101个年轮数据，我们发现当地气候，特别是气候水分亏缺，在树木生长敏感性的空间异质性中起主导作用。而地理空间变量则不那么重要。我们的分析揭示了东北亚森林中树木对干旱的易感性增加的普遍模式。具体而言，在气候水分亏缺严重的地点，在生长季节降水少、温度升高和干旱加剧的条件下，阔叶和针叶树的生长都持续减少。我们的研究结果表明，持续的气候变暖可能会进一步对树木的生长性能产生负面影响，特别是在东北亚森林的干燥地区。

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引用次数: 0

Increasing midday depression of mangrove photosynthesis with heat and drought stresses 炎热和干旱胁迫下正午红树林光合作用的增加

IF 5.6 1区农林科学 Q1 AGRONOMY

Agricultural and Forest Meteorology

Pub Date : 2024-12-18 DOI: 10.1016/j.agrformet.2024.110372

Zhu Zhu , Xudong Zhu

Midday depression of photosynthesis (MD) refers to the phenomenon that vegetation's photosynthetic rate decreases at midday experiencing environmental stresses. Mangrove MD and its responses to heat and drought stresses offer valuable insights into understanding the impact of climate change on mangrove blue carbon. However, the temporal variability of mangrove MD and its interactions with these stresses across short time scales remain less investigated. Here, we quantified mangrove MD using two diurnal metrics, relative midday depression (RMD) and diurnal centroid shift (DCS), and examined its responses to heat (air temperature) and drought (vapor pressure deficit (VPD) and rain) stresses in a subtropical estuarine wetland of Southeast China, based on six-year eddy covariance measurements from 2017 to 2022. The results indicate: (1) mangrove MD occurred at air temperature or VPD above a certain threshold but became severe when the stresses co-existed; (2) RMD performed better than DCS in measuring mangrove MD; (3) monthly RMD had a clear seasonal pattern peaking in summer (up to 26.1 %), while annual RMD (5.0 ∼ 10.2 %) changed with gross primary productivity (GPP) in the opposite direction; (4) RMD increased with both air temperature (1.01 ∼ 1.35 %/ °C) and VPD (8.41 ∼ 13.79 %/kPa) for each year but with different sensitivities; (5) larger annual sensitivities of RMD to both air temperature and VPD tended to occur in drier years with less rain. This study highlights the importance of heat and drought stresses in affecting mangrove MD and GPP, implying that future warmer and drier climates are likely to weaken mangrove carbon uptake. Future empirical and model studies on mangrove blue carbon should explicitly consider sub-daily interactions between mangrove MD and environmental stresses to reduce the uncertainty in assessing mangrove carbon budget in the context of climate change.

正午光合作用抑制（noon depression of光合作用，MD）是指植物在正午受到环境胁迫时光合作用速率下降的现象。红树林MD及其对高温和干旱胁迫的响应为理解气候变化对红树林蓝碳的影响提供了有价值的见解。然而，红树林MD的时间变异性及其在短时间尺度上与这些胁迫的相互作用的研究仍然较少。本文采用相对正午低气压（RMD）和日质心位移（DCS）两个日指标量化了中国东南部亚热带河口湿地的红树林MD，并基于2017 - 2022年6年的涡动相关方差测量，研究了红树林MD对热（气温）和干旱（蒸汽压差（VPD）和雨）胁迫的响应。结果表明：(1)红树林病害发生在气温或VPD高于某一阈值时，但在应力共存时病害加重；(2) RMD测量红树林MD优于DCS；(3)月RMD在夏季达到峰值（最高达26.1%），而年RMD（5.0 ~ 10.2%）随总初级生产力（GPP）呈相反方向变化；(4) RMD随气温（1.01 ~ 1.35% /°C）和VPD （8.41 ~ 13.79% /kPa）逐年增加，但敏感性不同；(5)在干旱少雨年份，RMD对气温和VPD的年敏感性都较大。该研究强调了高温和干旱胁迫在影响红树林MD和GPP中的重要性，这意味着未来更温暖和更干燥的气候可能会削弱红树林的碳吸收。未来红树林蓝碳的实证和模型研究应明确考虑红树林MD与环境压力之间的亚日相互作用，以减少气候变化背景下红树林碳收支评估的不确定性。

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引用次数: 0

Corrigendum to “Agreement of multiple night- and daytime filtering approaches of eddy covariance-derived net ecosystem CO2 exchange over a mountain forest” [Agricultural and Forest Meteorology Volume 356 (2024) 110173] “山区森林上涡动相关方差衍生的净生态系统CO2交换的多种夜间和白天过滤方法的一致性”[农业和森林气象学卷356(2024)110173]的勘误表

IF 5.6 1区农林科学 Q1 AGRONOMY

Agricultural and Forest Meteorology

Pub Date : 2024-12-18 DOI: 10.1016/j.agrformet.2024.110365

Alexander Platter , Katharina Scholz , Albin Hammerle , Mathias W. Rotach , Georg Wohlfahrt

引用次数: 0

Predicting CO2 and CH4 fluxes and their seasonal variations in a subarctic wetland under two shared socioeconomic pathway climate scenarios 预测两种共同社会经济路径气候情景下亚北极湿地的二氧化碳和甲烷通量及其季节变化

IF 5.6 1区农林科学 Q1 AGRONOMY

Agricultural and Forest Meteorology

Pub Date : 2024-12-16 DOI: 10.1016/j.agrformet.2024.110359

Bingqian Zhao , Wenxin Zhang , Peiyan Wang , Ludovica D'Imperio , Yijing Liu , Bo Elberling

The Arctic is undergoing a shift toward a warmer and wetter climate. Recent experiments indicate that the carbon balance of subarctic wet tundra is sensitive to both summer warming and deeper snow. However, few studies have combined experimental data with process-oriented models to predict how the terrestrial carbon cycle will respond to future climate change. Here, we use CoupModel, a process-oriented model, to investigate CO₂ and CH₄ dynamics in a subarctic wet tundra ecosystem under two contrasting climate change scenarios over the 21^st century. Our findings show that the model successfully reproduced the treatment effects of warming on CO₂ and CH₄ fluxes comparing to measurements from control, open top chambers and snow addition plots. For 2014–2020, the studied ecosystem functioned as a minor source of CH₄ and a neutral balance of CO₂, resulting in the overall greenhouse gas emissions of 10.5 ± 79.1 g CO₂-eq m^-2 yr^-1. The calibrated model was used to predict CO₂ and CH₄ fluxes and their seasonal variations under future climate scenarios. By 2100, a warmer climate could enhance the mean annual sink strength of CO₂ to 10.7 g C-CO₂ m^-2 yr^-1 under SSP126 (Shared Socioeconomic Pathway 1 and the radiative forcing level of 2.6 W m^-2) and 26.2 g C-CO₂ m^-2 yr^-1 under SSP585 (Shared Socioeconomic Pathway 5 and the radiative forcing level of 8.5 W/m²). However, increasing trends in the CH₄ budget were marginally small. The negligible response of CH₄ emission can be mainly explained by insignificantly wetter climate and limited soil C stock. For the radiative balance of the ecosystem, CO₂-equivalent flux of methane offset 78% of CO₂ sink in SSP126, and 31% in SSP585. Overall, the subarctic wet tundra transitions from being a source to a sink for greenhouse gases, excluding N₂O.

北极地区的气候正在向更温暖、更潮湿的方向转变。最近的实验表明，亚北极湿润苔原的碳平衡对夏季变暖和积雪加深都很敏感。然而，很少有研究结合实验数据和面向过程的模型来预测陆地碳循环将如何应对未来的气候变化。在这里，我们利用面向过程的模型 CoupModel，研究了在 21 世纪两种截然不同的气候变化情景下，亚北极湿润苔原生态系统中二氧化碳和甲烷的动态变化。我们的研究结果表明，与对照组、开顶室和加雪地块的测量结果相比，该模型成功地再现了气候变暖对二氧化碳和甲烷通量的处理效果。在 2014-2020 年期间，所研究的生态系统是甲烷的次要来源，而二氧化碳则保持中性平衡，因此温室气体总排放量为每年 10.5 ± 79.1 克二氧化碳当量 m-2。校准模型用于预测未来气候情景下的二氧化碳和甲烷通量及其季节变化。到 2100 年，在 SSP126（共享社会经济途径 1 和 2.6 W m-2 的辐射强迫水平）和 SSP585（共享社会经济途径 5 和 8.5 W/m² 的辐射强迫水平）下，气候变暖可将二氧化碳的年均汇强度提高到 10.7 g C-CO2 m-2 yr-1，而在 SSP585（共享社会经济途径 5 和 8.5 W/m² 的辐射强迫水平）下，二氧化碳的年均汇强度可提高到 26.2 g C-CO2 m-2 yr-1。然而，CH4 预算的增长趋势很小。CH4排放量的微弱反应主要是由于气候明显变湿和土壤中的碳储量有限。就生态系统的辐射平衡而言，在 SSP126 和 SSP585 中，甲烷的 CO2 当量分别抵消了 78% 和 31% 的 CO2 吸收汇。总体而言，亚北极湿润苔原从温室气体的源转变为汇，但不包括一氧化二氮。

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引用次数: 0

Exploring unresolved inquiries regarding the meaning of Reynolds averaging and decomposition: A review 探索关于雷诺平均和分解意义的未解决的问题：综述

IF 5.6 1区农林科学 Q1 AGRONOMY

Agricultural and Forest Meteorology

Pub Date : 2024-12-16 DOI: 10.1016/j.agrformet.2024.110364

Andrew S. Kowalski , Jesús Abril-Gago

In the late 19th century, Osborne Reynolds published two papers whose impact on atmospheric turbulence studies can hardly be overstated. The first, Reynolds (1883) established both his eponymous, dimensionless number and his reputation as the father of turbulence science, which is beyond doubt. However, his second famous paper (Reynolds, 1895) sowed seeds of confusion regarding the mathematical separation of average (mean) and fluctuating (turbulent) components of a fluid flow. Here, we revisit both the prehistory and after-effects of Reynolds's second famous article, which seems to have been published largely thanks to his already entrenched reputation.

We show that successions of authors have misrepresented Reynolds's innovations – now known as Reynolds averaging and decomposition (RAAD) –, putting his name to methodologies that he never intended. We attribute this, in part, to Reynolds's predilection for long, inscrutable sentences, as well as his self-contradiction regarding the methodology for averaging the normal stress (or pressure). We examine two additional issues that are intimately related to using RAAD to define turbulent fluxes, namely its application to intensive versus extensive variables and the appearance of “Leonard terms” in the averaged equation of motion, neither of which is completely resolved. Throughout the manuscript, we identify a set of unanswered questions concerning RAAD and conclude that a complete mathematical description of turbulence is unlikely to emerge without addressing these issues, including the original inconsistency that was introduced by Osborne Reynolds himself.

19世纪末，奥斯本·雷诺兹（Osborne Reynolds）发表了两篇论文，对大气湍流研究的影响怎么强调都不为过。第一个是雷诺兹（1883年），他以自己的名字命名了无量纲数，并因此获得了湍流科学之父的声誉，这是毋庸置疑的。然而，他的第二篇著名论文（雷诺兹，1895年）播下了关于流体流动的平均（平均）和波动（湍流）成分的数学分离的混乱种子。在这里，我们重温雷诺兹第二篇著名文章的前世和后续影响，这篇文章的发表似乎很大程度上要归功于他已经确立的声誉。我们表明，历代作者都歪曲了雷诺兹的创新——现在被称为雷诺兹平均和分解（RAAD）——把他的名字放在了他从未想过的方法上。我们把这部分归因于雷诺兹对长而难懂的句子的偏爱，以及他在平均正常压力（或压力）的方法上的自相矛盾。我们研究了与使用RAAD来定义湍流通量密切相关的另外两个问题，即它在密集变量与广泛变量中的应用以及平均运动方程中“伦纳德项”的出现，这两个问题都没有完全解决。在整个手稿中，我们确定了一组关于RAAD的未解决的问题，并得出结论，如果不解决这些问题，包括奥斯本雷诺兹自己引入的原始不一致，湍流的完整数学描述不太可能出现。

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引用次数: 0

Global pattern in terrestrial leaf litter decomposition: The effects of climate, litter chemistry, life form, growth form and mycorrhizal association 陆生凋落叶分解的全球格局：气候、凋落叶化学、生命形式、生长形式和菌根关联的影响

IF 5.6 1区农林科学 Q1 AGRONOMY

Agricultural and Forest Meteorology

Pub Date : 2024-12-14 DOI: 10.1016/j.agrformet.2024.110368

Xiaoxiang Zhao , Qiuxiang Tian , Anders Michelsen , Boshen Ren , Zhiyang Feng , Long Chen , Qinghu Jiang , Rudong Zhao , Feng Liu

Leaf litter decomposition plays an important role in nutrient and carbon cycling in terrestrial ecosystems. However, at a global scale, the effects of climate, initial litter chemistry, and different plant functional types on litter decomposition are not fully understood. Additionally, it remains unclear whether the effects of litter chemistry on leaf litter decomposition are consistent with responses observed at local scales. Here, 1585 observations of leaf litter decomposition encompassing 861 species from 298 field studies were synthesized to investigate the effects of climate, litter initial chemistry, and various plant groups on decomposition rates. The results demonstrate that at a global scale, leaf litter decomposition rates increased with mean annual temperature (MAT), mean annual precipitation (MAP), initial litter concentrations of nitrogen (N), phosphorus (P), and magnesium (Mg), but decreased with initial lignin concentrations. Moreover, except for initial leaf litter Mg concentrations, the influence of initial leaf litter chemistry characteristics on decomposition rates were consistent at global and local scales. In woody plants, leaf litters from deciduous, broadleaf, and arbuscular mycorrhizal (AM) species exhibited faster decomposition rates than from evergreen, coniferous, and ectomycorrhizal (ECM) species leaf litters, respectively. In herbaceous plants, the leaf litter of forbs had faster decomposition rates than graminoid and leguminous plants. For all plants, leaf litter decomposition is primarily controlled by MAP and MAT globally, while for woody and herbaceous plants, leaf litter decomposition is primarily controlled by initial leaf N and P concentrations, respectively. These results indicated that various functional groups of plants play a crucial role in understanding the decomposition of leaf litter. Moreover, when investigating the effect of leaf litter initial chemistry on its decomposition, it is almost unnecessary to consider effects at different scales.

落叶分解在陆地生态系统的养分和碳循环中发挥着重要作用。然而，在全球范围内，气候、初始落叶化学和不同植物功能类型对落叶分解的影响尚未完全明了。此外，目前还不清楚落叶化学对落叶分解的影响是否与在局部尺度上观察到的反应一致。本文综合了298项野外研究中对861个物种的1585次枯落叶分解观测，研究了气候、枯落叶初始化学性质和不同植物群对枯落叶分解率的影响。结果表明，在全球范围内，枯落叶分解率随年平均气温（MAT）、年平均降水量（MAP）、枯落叶初始氮（N）、磷（P）和镁（Mg）浓度的增加而增加，但随初始木质素浓度的增加而减少。此外，除初始落叶层镁浓度外，在全球和地方尺度上，初始落叶层化学特征对分解率的影响是一致的。在木本植物中，落叶、阔叶和丛枝菌根（AM）物种叶屑的分解速率分别快于常绿、针叶和外生菌根（ECM）物种叶屑的分解速率。在草本植物中，牧草的落叶分解速度快于禾本科植物和豆科植物。对所有植物而言，叶屑的分解主要受全球 MAP 和 MAT 的控制，而对木本植物和草本植物而言，叶屑的分解分别主要受初始叶片 N 和 P 浓度的控制。这些结果表明，植物的不同功能群对了解落叶的分解起着至关重要的作用。此外，在研究落叶初始化学成分对落叶分解的影响时，几乎没有必要考虑不同尺度的影响。

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引用次数: 0

Risk prediction of Lecanosticta acicola spore abundance in Atlantic climate regions 大西洋气候区 Lecanosticta acicola 孢子丰度的风险预测

IF 5.6 1区农林科学 Q1 AGRONOMY

Agricultural and Forest Meteorology

Pub Date : 2024-12-14 DOI: 10.1016/j.agrformet.2024.110360

David García-García , Nebai Mesanza , Rosa Raposo , Mª Teresa Pascual , Iskander Barrena , Amaia Urkola , Nagore Berano , Eugenia Iturritxa

Brown spot needle blight disease, caused by the fungus Lecanosticta acicola, affects pine trees across the northern hemisphere. In recent years, its incidence has expanded to new areas and host species. This is in association with climate change. Interest in understanding the basis of its epidemiology and proposing appropriate management measures has also increased. However, there is a lack of studies that characterise the relationship between spore abundance trends and climatic factors, which are essential to understand the spread of the disease. We collected spore abundance data for three years from 16 traps located in pine plantations over the Basque Country (north of Spain), the first European region where L. acicola was detected. A rapid change in pathogen behaviour led to serious financial losses in the forestry sector. We then modelled the relationship between spore abundance and weather variables in terms of generalised additive models. The resulting model was used to estimate the risk of disease spread over the whole area of Basque Country. We also generated a risk projection for the north of the Iberian Peninsula, an area influenced by the Atlantic climate, where the disease is currently causing severe damage. Cumulative rainfall acted as a reliable predictor of the spore abundance of the pathogen; thus, data from weather stations can be directly incorporated into early warning protocols to inform effective preventive actions.

由真菌Lecanosticta acicola引起的褐斑针叶枯病影响整个北半球的松树。近年来，其发病率已扩大到新的地区和寄主物种。这与气候变化有关。对了解其流行病学基础和提出适当管理措施的兴趣也有所增加。然而，缺乏描述孢子丰度趋势与气候因素之间关系的研究，而气候因素对于了解该病的传播至关重要。我们从位于巴斯克地区（西班牙北部）松树种植园的16个陷阱中收集了三年的孢子丰度数据，巴斯克地区是第一个检测到L. acicola的欧洲地区。病原体行为的迅速变化给林业部门造成了严重的经济损失。然后，我们根据广义加性模型模拟了孢子丰度和天气变量之间的关系。由此产生的模型被用来估计疾病在整个巴斯克地区传播的风险。我们还对受大西洋气候影响的伊比利亚半岛北部地区进行了风险预测，该地区目前正在造成严重破坏。累积降雨量是病原菌孢子丰度的可靠预测因子；因此，气象站的数据可以直接纳入预警方案，为有效的预防行动提供信息。

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引用次数: 0

Effects of elevated ozone on evapotranspiration and energy allocation of rice ecosystem under fully open-air field conditions 全露天条件下臭氧浓度升高对水稻生态系统蒸散和能量分配的影响

IF 5.6 1区农林科学 Q1 AGRONOMY

Agricultural and Forest Meteorology

Pub Date : 2024-12-13 DOI: 10.1016/j.agrformet.2024.110363

Yujie Zhang , Jianghua Wu , Yansen Xu , Yuqing Zhou , Shiyun Xu , Zhaozhong Feng

Evapotranspiration (ET) and its induced perturbations in the surface energy balance have significant impacts on the carbon cycle, water cycle, and regional climate. The partitioning of ET (transpiration (T) and evaporation (E)) has significant implications for agricultural production and water management. Rising tropospheric ozone (O₃) concentrations currently alter leaf stomatal conductance, which may affect ET. Paddy fields are characterized by flooding (during most of the growth period), vigorous crop ET, and a high percentage of E in ET. This may cause differences in the effects of elevated O₃ on the ET in rice fields relative to previously reported dryland crops. Based on 3 years of in-situ observations, this study investigated energy allocation in a rice ecosystem using the energy balance residual method under two O₃ treatments (1.5 times ambient air (AA; E-O₃) and AA) at a Free Air O₃ Concentration Enrichment facility. E-O₃ caused a trend of higher net radiative flux (R_n) and sensible heat flux (H) in rice but only reached statistical significance on some days and at specific growth stages (e.g., jointing or booting) compared with AA. E-O₃ attenuated the degree of response in energy allocation owing to the unique land-use patterns of paddy fields and climatic conditions during rice growth. Based on the modified Priestley–Taylor model, T decreased significantly at the grain-filling stage, and E increased during the full reproductive period, causing a significant increase in ET on some days after exposure to elevated O₃. In conclusion, rice ecosystems have a weaker capacity to influence the water cycle and regional climate than drylands regarding rising O₃ concentrations. However, the effects of E-O₃ on E and T adversely affect the carbon cycle and agricultural production, indicating the need to optimize agricultural water management and cropping strategies under high O₃ concentration region.

蒸散发及其引起的地表能量平衡扰动对碳循环、水循环和区域气候具有重要影响。蒸散发(蒸腾（T)和蒸发(E)）的分配对农业生产和水管理具有重要意义。目前，对流层臭氧（O3）浓度的上升改变了叶片气孔导度，这可能会影响ET。水田的特点是（在大部分生长期）淹水，作物ET旺盛，ET中E的比例很高。这可能导致O3升高对稻田ET的影响与先前报道的旱地作物不同。基于3年的原位观测，采用能量平衡剩余法研究了两种O3处理(1.5倍环境空气浓度；E-O3)和AA)在自由空气O3浓度富集设施。与AA相比，E-O3增加了水稻的净辐射通量（Rn）和感热通量(H)，但仅在某些日子和特定生育阶段（如拔节期或孕穗期）达到统计学意义。由于稻田独特的土地利用方式和水稻生长期间的气候条件，E-O3在能量分配上的响应程度减弱。根据改良的Priestley-Taylor模型，T在灌浆期显著降低，E在全生育期显著增加，导致O3升高后的某些天ET显著增加。综上所述，水稻生态系统在O3浓度上升方面对水循环和区域气候的影响能力弱于旱地。然而，E-O3对E和T的影响对碳循环和农业生产产生不利影响，表明需要优化O3高浓度地区的农业用水管理和种植策略。

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引用次数: 0

Revisiting snowmelt dynamics and its impact on soil moisture and vegetation in mid-high latitude watershed over four decades 回顾40年来中高纬度流域融雪动态及其对土壤水分和植被的影响

IF 5.6 1区农林科学 Q1 AGRONOMY

Agricultural and Forest Meteorology

Pub Date : 2024-12-13 DOI: 10.1016/j.agrformet.2024.110353

Dongsheng Li , Wei Ouyang , Lei Wang , Jing Chen , He Zhang , Anarmaa Sharkhuu , Soyol-Erdene Tseren-Ochir , Yang Yang

Snowmelt is a critical water supply that affects the environmental security and sustainable development. However, the dynamic contributions of climatic factors to snowmelt and their impacts on soil moisture (SM) and vegetation growth remain unclear. In this study, by combining changes in spring snowmelt (snow water equivalent), climatic factors (precipitation and temperature), SM, and vegetation growth (normalized difference vegetation index [NDVI]) during 1982–2018, the spatiotemporal patterns in snowmelt and its mutual effects on SM and NDVI in a mid-high latitude watershed (Mongolia) were investigated. The results showed that spring snowmelt has decreased (-0.54 m/yr, p < 0.05) in Mongolia, with cold season temperature and precipitation identified as key influencing factors. The negative association between cold season temperature and snowmelt is intensifying (-0.0010 mm/yr, p > 0.05), while the positive influence of cold season precipitation is weakening (-0.0004 mm/yr, p > 0.05). Additionally, snowmelt provides 30 % of SM, and rising spring temperatures, along with reduced snowmelt, is the main reasons for SM decline (0.001 m³/m³/yr, p < 0.05). The negative impact of spring temperature on SM is growing (-0.0029 %/yr, p < 0.05), while snowmelt's positive contribution is diminishing (-0.0011 %/yr, p < 0.05). Furthermore, spring temperature has the strongest direct effect (positive) on vegetation, while SM exerts the greatest total influence (positive). Snowmelt indirectly affects (positive) vegetation through its role in SM. Despite vegetation increased in 60.5 % of the area, the declining trends in SM and snowmelt, alongside the reduced contribution of SM to vegetation (-0.0028/yr, p < 0.05), suggest an increased risk of future drought. Overall, this study provides new insights into the dynamics and interrelationships between snowmelt, SM, and vegetation in mid-to-high latitude regions, offering valuable implications for sustainable development decision-making.

融雪是影响环境安全和可持续发展的重要水源。然而，气候因子对融雪的动态贡献及其对土壤水分和植被生长的影响尚不清楚。结合1982-2018年春季融雪（雪水等值）、气候因子（降水和温度）、SM和植被生长（归一化植被指数[NDVI]）的变化，研究了中高纬流域（蒙古）融雪的时空格局及其对SM和NDVI的相互影响。结果表明，春季融雪量减少(-0.54 m/yr, p <；0.05)，冷季温度和降水是主要影响因素。冷季温度与融雪的负相关正在增强(-0.0010 mm/yr, p >；0.05)，而冷季降水的正向影响正在减弱(-0.0004 mm/yr, p >；0.05)。此外，融雪量提供了30%的融雪量，春季气温上升和融雪量减少是融雪量下降的主要原因(0.001 m³/m³/yr, p <；0.05)。春季温度对SM的负面影响越来越大(- 0.0029% /yr, p <；0.05)，而融雪的正贡献正在减小(- 0.0011% /年，p <；0.05)。春季气温对植被的直接影响最大（正），而SM对植被的总影响最大（正）。融雪通过其在SM中的作用间接影响（正）植被。尽管植被增加了60.5%，但SM和融雪量呈下降趋势，SM对植被的贡献减少(-0.0028/yr, p <；0.05)，表明未来干旱的风险增加。总体而言，本研究为中高纬度地区融雪、SM和植被之间的动态关系和相互关系提供了新的见解，为可持续发展决策提供了有价值的启示。

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