Influence of rain pulse characteristics over intrastorm throughfall hot  moments

Abstract. Forest canopy alters the amount of rainfall reaching the surface by redistributing it as throughfall. Throughfall is critical to watershed ecological variables (soil moisture, stream water discharge/chemistry, and stormflow pathways) and controlled by canopy structural interactions with meteorological conditions across temporal scales (from seasonal to within-event). This work uses complete linkage cluster analysis to identify intrastorm rain pulses of distinct meteorological conditions (beginning-of-storm and internal-to-storm pulses that are atmospherically dry, moderate, or wet), relates each cluster to intrastorm throughfall responses, then applies multiple correspondence analyses (MCAs) to a range of meteorological thresholds (median intensity, coefficient of variation (CV) of intensity, mean wind-driven droplet inclination angle, and CV of wind speed) for identification of interacting storm conditions corresponding to hot moments in throughfall generation (≥ 80% of rainfall). Equalling/exceeding rain intensity thresholds (median and CV) corresponded with throughfall hot moments across all rain pulse types. Under these intensity conditions, two wind mechanisms produced significant correspondences: (1) high wind-driven droplet inclination angles under steady wind increased surface wetting; and (2) sporadic winds shook entrained droplets from surfaces. Correspondences with these threshold conditions were greatest for pulses of moderate vapour pressure deficit (VPD), but weakest under high VPD. Weaker correspondences between throughfall hot moments and meteorological thresholds for high VPD pulses may be because canopy structures were not included in the MCA. In that vein, strongest meteorological threshold correspondences to throughfall hot moments at our site may be a function of heavy T. usneoides coverage. Future applications of MCA within other forests are, therefore, recommended to characterize how throughfall hot moments may be affected along drainage paths dependent on different structures (leaves, twigs, branches, etc.).

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Exploring how groundwater buffers the influence of heatwaves on vegetation function during multi-year droughts

Earth System Dynamics ◽

10.5194/esd-12-919-2021 ◽

2021 ◽

Vol 12 (3) ◽

pp. 919-938

Author(s):

Mengyuan Mu ◽

Martin G. De Kauwe ◽

Anna M. Ukkola ◽

Andy J. Pitman ◽

Weidong Guo ◽

...

Keyword(s):

Land Surface ◽

Forest Canopy ◽

Climate Models ◽

Root Zone ◽

Stomatal Closure ◽

Capillary Rise ◽

Vapour Pressure Deficit ◽

Global Climate Models ◽

Surface Model ◽

The Impact

Abstract. The co-occurrence of droughts and heatwaves can have significant impacts on many socioeconomic and environmental systems. Groundwater has the potential to moderate the impact of droughts and heatwaves by moistening the soil and enabling vegetation to maintain higher evaporation, thereby cooling the canopy. We use the Community Atmosphere Biosphere Land Exchange (CABLE) land surface model, coupled to a groundwater scheme, to examine how groundwater influences ecosystems under conditions of co-occurring droughts and heatwaves. We focus specifically on south-east Australia for the period 2000–2019, when two significant droughts and multiple extreme heatwave events occurred. We found groundwater plays an important role in helping vegetation maintain transpiration, particularly in the first 1–2 years of a multi-year drought. Groundwater impedes gravity-driven drainage and moistens the root zone via capillary rise. These mechanisms reduced forest canopy temperatures by up to 5 ∘C during individual heatwaves, particularly where the water table depth is shallow. The role of groundwater diminishes as the drought lengthens beyond 2 years and soil water reserves are depleted. Further, the lack of deep roots or stomatal closure caused by high vapour pressure deficit or high temperatures can reduce the additional transpiration induced by groundwater. The capacity of groundwater to moderate both water and heat stress on ecosystems during simultaneous droughts and heatwaves is not represented in most global climate models, suggesting that model projections may overestimate the risk of these events in the future.

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QUALITY CHARACTERISTICS OF SURFACE WATERS AT ASPROLAKKAS RIVER BASIN, N.E. CHALKIDIKI, GREECE

Bulletin of the Geological Society of Greece ◽

10.12681/bgsg.11359 ◽

2017 ◽

Vol 43 (4) ◽

pp. 1737

Author(s):

E. Kelepertzis ◽

A. Argyraki ◽

E. Daftsis ◽

D. Ballas

Keyword(s):

Surface Waters ◽

Water Samples ◽

Major Ions ◽

Stream Water ◽

Water Discharge ◽

Sampling Period ◽

Quality Characteristics ◽

Sampling Point ◽

The Past ◽

Surface Water Samples

The present study reports on a four sampling period (April 2008-July 2008-November 2008-February 2009) study of water quality in streams of NE Chalkidiki. A total of 80 surface water samples were collected and analysed for the major ions Ca2+, Mg2+, K+, Na+, Cl- , HCO3 - , SO4 2-, NO3 - and the trace elements Pb, Fe, Cd, Cu, Cr, Ni, Zn, Mn and As. Also pH, Electrical Conductivity (EC), Total Dissolved Solids (TDS), Temperature, as well as the stream water discharge at each sampling point, were determined in the field. The treatment and the subsequent evaluation of the data showed that the water samples are divided into three separate groups, reflecting the chemistry of water in the three sub-basins of the area i.e., Kokkinolakkas, Kerasia and Piavitsa. The water of the first one is possibly affected by the past mining activities of the area, whereas samples from the other two reflect the influence of sulphide mineralization on the hydrogeochemistry of the corresponding streams. No effect of the seasonal differentiation of stream water discharge was observed.

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Extension of the Optical Diffraction Analysis Technique for Estimating Forest Canopy Geometry.

Australian Journal of Botany ◽

10.1071/bt9790575 ◽

1979 ◽

Vol 27 (5) ◽

pp. 575 ◽

Cited By ~ 11

Author(s):

DS Kimes ◽

JA Smith ◽

JK Berry

Keyword(s):

Diffraction Analysis ◽

Pinus Contorta ◽

Forest Canopy ◽

Optical Diffraction ◽

Angle Distribution ◽

Coordinate Transformations ◽

Frequency Distributions ◽

Analysis Technique ◽

Inclination Angles

Optical diffraction analysis of in situ ground photographs has previously been used to estimate foliage angle distributions in grassland canopies. These canopies are typically characterized by a single component-leaves-and the foliage is highly linear in nature. In this paper, the diffraction technique is extended to a multicomponent forest canopy containing needles and branches. Additional convolution and coordinate transformations are used to estimate the branch and needle angle frequency distributions for top, middle, and base sections of two lodgepole pine (Pinus contorta) trees. The resulting distributions show that the branch inclination angles tend to increase as one proceeds to the tree tops. The needle inclination angle distribution was relatively constant for all layers, and it is believed that this distribution is characteristic of a large class of needle-bearing species.

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Ba/Sr, Ca/Sr and 87Sr/86Sr ratios in soil water and groundwater: implications for relative contributions to stream water discharge

Applied Geochemistry ◽

10.1016/s0883-2927(99)00054-2 ◽

2000 ◽

Vol 15 (3) ◽

pp. 311-325 ◽

Cited By ~ 96

Author(s):

Magnus Land ◽

Johan Ingri ◽

Per S Andersson ◽

Björn Öhlander

Keyword(s):

Soil Water ◽

Stream Water ◽

Water Discharge

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The UK Environmental Change Network datasets – integrated and co-located data for long-term environmental research (1993–2015)

10.5194/essd-2019-74 ◽

2019 ◽

Cited By ~ 1

Author(s):

Susannah Rennie ◽

Chris Andrews ◽

Sarah Atkinson ◽

Deborah Beaumont ◽

Sue Benham ◽

...

Keyword(s):

Environmental Change ◽

Stream Water ◽

Water Discharge ◽

Solution Chemistry ◽

Research Network ◽

Environmental Research ◽

Wide Range ◽

Environmental Change Network ◽

The Uk

Abstract. Long-term datasets of integrated environmental variables, co-located together, are relatively rare. The UK Environmental Change Network (ECN) was launched in 1992 and provides the UK with its only long-term integrated environmental monitoring and research network for the assessment of the causes and consequences of environmental change. Measurements, covering a wide range of physical, chemical and biological "driver" and "response" variables are made in close proximity at ECN terrestrial sites using protocols incorporating standard quality control procedures. This paper describes the datasets (there are nineteen published ECN datasets) for these co-located measurements, containing over twenty years of data (1993–2015). The data and supporting documentation are freely available from the NERC Environmental Information Data Centre under the terms of the Open Government Licence using the following DOI’s: Meteorology Meteorology: https://doi.org/10.5285/fc9bcd1c-e3fc-4c5a-b569-2fe62d40f2f5 (Rennie et al., 2017a) Biogeochemistry Atmospheric nitrogen chemistry: https://doi.org/10.5285/baf51776-c2d0-4e57-9cd3-30cd6336d9cf (Rennie et al., 2017b) Precipitation chemistry: https://doi.org/10.5285/18b7c387-037d-4949-98bc-e8db5ef4264c (Rennie et al., 2017c) Soil solution chemistry: https://doi.org/10.5285/b330d395-68f2-47f1-8d59-3291dc02923b (Rennie et al., 2017d) Stream water chemistry: https://doi.org/10.5285/fd7ca5ef-460a-463c-ad2b-5ad48bb4e22e (Rennie et al., 2017e) Stream water discharge: https://doi.org/10.5285/8b58c86b-0c2a-4d48-b25a-7a0141859004 (Rennie et al., 2017f) Invertebrates Moths: https://doi.org/10.5285/a2a49f47-49b3-46da-a434-bb22e524c5d2 (Rennie et al., 2017g) Butterflies: https://doi.org/10.5285/5aeda581-b4f2-4e51-b1a6-890b6b3403a3 (Rennie et al., 2017h) Carabid beetle: https://doi.org/10.5285/8385f864-dd41-410f-b248-028f923cb281 (Rennie et al., 2017i) Spittle bugs: https://doi.org/10.5285/aff433be-0869-4393-b765-9e6faad2a12b (Rennie et al., 2018) Vegetation Baseline: https://doi.org/10.5285/a7b49ac1-24f5-406e-ac8f-3d05fb583e3b (Rennie et al., 2016a) Coarse grain: https://doi.org/10.5285/d349babc-329a-4d6e-9eca-92e630e1be3f (Rennie et al., 2016b) Woodland: https://doi.org/10.5285/94aef007-634e-42db-bc52-9aae86adbd33 (Rennie et al., 2017j) Fine grain: https://doi.org/10.5285/b98efec8-6de0-4e0c-85dc-fe4cdf01f086 (Rennie et al., 2017k) Vertebrates Frogs: https://doi.org/10.5285/4d8c7dd9-8248-46ca-b988-c1fc38e51581 (Rennie et al., 2017l) Birds (Breeding bird survey): https://doi.org/10.5285/5886c3ba-1fa5-49c0-8da8-40e69a10d2b5 (Rennie et al., 2017m) Birds (Common bird census): https://doi.org/10.5285/8582a02c-b28c-45d2-afa1-c1e85fba023d (Rennie et al., 2017n) Bats: https://doi.org/10.5285/2588ee91-6cbd-4888-86fc-81858d1bf085 (Rennie et al., 2017o) Rabbits and deer: https://doi.org/10.5285/0be0aed3-f205-4f1f-a65d-84f8cfd8d50f (Rennie et al., 2017p).

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Discharge and Temperature Controls of Dissolved Organic Matter (DOM) in a Forested Coastal Plain Stream

Water ◽

10.3390/w13202919 ◽

2021 ◽

Vol 13 (20) ◽

pp. 2919

Author(s):

Yuehan Lu ◽

Peng Shang ◽

Shuo Chen ◽

Yingxun Du ◽

Marco Bonizzoni ◽

...

Keyword(s):

Organic Matter ◽

Dissolved Organic Matter ◽

High Temperatures ◽

Coastal Plain ◽

Stream Water ◽

Water Discharge ◽

Low Flow ◽

Fluorescence Excitation ◽

In Situ Modification ◽

Total Fluorescence

Streams in the southeastern United States Coastal Plains serve as an essential source of energy and nutrients for important estuarine ecosystems, and dissolved organic matter (DOM) exported from these streams can have profound impacts on the biogeochemical and ecological functions of fluvial networks. Here, we examined hydrological and temperature controls of DOM during low-flow periods from a forested stream located within the Coastal Plain physiographic region of Alabama, USA. We analyzed DOM via combining dissolved organic carbon (DOC) analysis, fluorescence excitation–emission matrix combined with parallel factor analysis (EEM-PARAFAC), and microbial degradation experiments. Four fluorescence components were identified: terrestrial humic-like DOM, microbial humic-like DOM, tyrosine-like DOM, and tryptophan-like DOM. Humic-like DOM accounted for ~70% of total fluorescence, and biodegradation experiments showed that it was less bioreactive than protein-like DOM that accounted for ~30% of total fluorescence. This observation indicates fluorescent DOM (FDOM) was controlled primarily by soil inputs and not substantially influenced by instream production and processing, suggesting that the bulk of FDOM in these streams is transported to downstream environments with limited in situ modification. Linear regression and redundancy analysis models identified that the seasonal variations in DOM were dictated primarily by hydrology and temperature. Overall, high discharge and shallow flow paths led to the enrichment of less-degraded DOM with higher percentages of microbial humic-like and tyrosine-like compounds, whereas high temperatures favored the accumulation of high-aromaticity, high-molecular-weight, terrestrial, humic-like compounds in stream water. The flux of DOC and four fluorescence components was driven primarily by water discharge. Thus, the instantaneous exports of both refractory humic-like DOM and reactive protein-like DOM were higher in wetter seasons (winter and spring). As high temperatures and severe precipitation are projected to become more prominent in the southeastern U.S. due to climate change, our findings have important implications for future changes in the amount, source, and composition of DOM in Coastal Plain streams and the associated impacts on downstream carbon and nutrient supplies and water quality.

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Assessing Forest Canopy Impacts on Smoke Concentrations Using a Coupled Numerical Model

Atmosphere ◽

10.3390/atmos10050273 ◽

2019 ◽

Vol 10 (5) ◽

pp. 273 ◽

Cited By ~ 4

Author(s):

Joseph J. Charney ◽

Michael T. Kiefer ◽

Shiyuan Zhong ◽

Warren E. Heilman ◽

Jovanka Nikolic ◽

...

Keyword(s):

Air Quality ◽

Numerical Model ◽

Forest Canopy ◽

Weather Prediction ◽

Time Of Day ◽

Meteorological Conditions ◽

Heat Fluxes ◽

Low Intensity ◽

Coupled Numerical Model ◽

The Impact

The impact of a forest canopy on smoke concentration is assessed by applying a numerical weather prediction model coupled with a Lagrangian particle dispersion model to two low-intensity wildland (prescribed) fires in the New Jersey Pine Barrens. A comparison with observations indicates that the coupled numerical model can reproduce some of the observed variations in surface smoke concentrations and plume heights. Model sensitivity analyses highlight the effect of the forest canopy on simulated meteorological conditions, smoke concentrations, and plume heights. The forest canopy decreases near-surface wind speed, increases buoyancy, and increases turbulent mixing. Sensitivities to the time of day, plant area density profiles, and fire heat fluxes are documented. Analyses of temporal variations in smoke concentrations indicate that the effect of the transition from a daytime to a nocturnal planetary boundary layer is weaker when sensible heat fluxes from the fires are stronger. The results illustrate the challenges in simulating meteorological conditions and smoke concentrations at scales where interactions between the fire, fuels, and atmosphere are critically important. The study demonstrates the potential for predictive tools to be developed and implemented that could help fire and air-quality managers assess local air-quality impacts during low-intensity wildland fires in forested environments.

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Leaf trait variation in three species through canopy strata in a semi-evergreen Neotropical forest

Canadian Journal of Botany ◽

10.1139/b03-031 ◽

2003 ◽

Vol 81 (4) ◽

pp. 398-404 ◽

Cited By ~ 9

Author(s):

Laura Yáñez-Espinosa ◽

Teresa Terrazas ◽

Lauro López-Mata ◽

Juan Ignacio Valdez-Hernández

Keyword(s):

Environmental Variables ◽

Forest Canopy ◽

Structural Changes ◽

Leaf Shape ◽

Vapour Pressure Deficit ◽

Leaf Structure ◽

Leaf Trait ◽

Neotropical Forest ◽

Shade Tolerant Species ◽

Canonical Variates

Morphological and structural changes among and within leaves of Aphananthe monoica (Hemsley) Leroy, Pleuranthodendron lindenii (Turczaninov) Sleumer, and Psychotria costivenia Grisebach were documented through canopy strata (<10, 1020, and >20 m high) and related to some environmental variables in a semi-evergreen Neotropical forest. The principal components analysis revealed that two components explained 93% of total variation. The first component (76.4%) denoted leaf structure, whereas the second (16.6%) denoted leaf shape. Anatomical differences in transverse leaf sections among different canopy strata were observed in Aphananthe monoica and Pleuranthodendron lindenii. Variance analyses showed significant differences among strata for leaf characters and light, relative humidity, vapour pressure deficit, and temperature. Canonical correlation analysis revealed that the first pair of canonical variates of leaf characters and environmental variables were closely related. The first environmental variate represented the changes in microclimate along forest canopy strata. Leaf structure observed in Aphananthe monoica and Pleuranthodendron lindenii suggested that they are intermediate shade-tolerant species, and Psychotria costivenia is a shade-tolerant understorey species. Aphananthe monoica and Pleuranthodendron lindenii, which during their life span occupy different positions in the vertical strata, showed the highest leaf variation.Key words: tropical trees, Aphananthe monoica, Pleuranthodendron lindenii, Psychotria costivenia, leaf variation, Veracruz.

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ORIENTATION OF SORBUS AUCUPARIA LEAVES BY THE RESULTS OF FIELD SURVEYS IN THE TERRITORY OF THE LENINGRAD REGION

10.31799/978-5-8088-1558-2-2021-2-138-142 ◽

2021 ◽

Author(s):

I. V. Matelenok ◽

◽

F. A. Alekseev ◽

E. A. Evdokimova ◽

◽

...

Keyword(s):

Forest Canopy ◽

Integral Function ◽

Leaf Angle ◽

Distribution Data ◽

Leningrad Region ◽

Angle Distribution ◽

Office Work ◽

Sorbus Aucuparia ◽

Inclination Angles ◽

Leaf Angle Distribution

Methods for retrieving leaf inclination angles in a forest canopy are considered. To acquire data on the orientation of Sorbus aucuparia leaves, a technique based on leveled camera digital photography well suited for conducting surveys in a boreal forest was used. In the course of field and office work, leaf angle distribution data for the specified species in the Priozersky district of the Leningrad region was obtained and analyzed. Values of the Ross-Nielson integral function were estimated.

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Water Quality Index Performance for River Pollution Control Based on Better Ecological Point of View (A Case Study in Code, Winongo, Gadjah Wong Streams)

Journal of the Civil Engineering Forum ◽

10.22146/jcef.41165 ◽

2019 ◽

Vol 5 (1) ◽

pp. 47

Author(s):

Sri Puji Saraswati ◽

Mochammad Venly Ardion ◽

Yul Hendro Widodo ◽

Suwarno Hadisusanto

Keyword(s):

Water Quality ◽

River Water ◽

Pollution Control ◽

Water Quality Index ◽

Quality Index ◽

Stream Water ◽

Water Discharge ◽

Monitoring Data ◽

Quality Data ◽

Water Quality Variables

The quality of river water quality monitoring data sometimes can be inaccurate. Evaluation of the effectiveness of water pollution control programs needs good quality data to calculate the Water Quality Index (WQI) with the aim to meet the requirement to protect biodiversity and maintain various water functions. Thirty-five water quality variables from Code, Gadjah Wong, and Winongo rivers were taken as data, conducted by Environmental Agency of Yogyakarta in 2004 – 2015. There were only 19 out of 35 water quality variables having good data after improvement of monitoring data, transformation/standardization and analysis of the significant water quality variables with PCA (Principle Component Analysis) and Factor Analysis (FA). WQIs formula in the three rivers used the same 5 significant variables i.e. EC, DO, COD, NH3N, Total Coliform, and "weighted sum index” as the sub-index aggregation technique, with different sub-index coefficients. Winongo River had the best water quality and Gajah Wong River was the worst. According to the relationship of river water discharge and WQIs index, large discharge during rainy seasons does not always decrease the level of pollution, but it tends to increase the WQIs. More effective ways to improve the stream water quality during dry seasons should further be investigated.

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