Contribution of understory evaporation in a tropical wet forest during the dry season

Jiménez-Rodríguez, César; Coenders-Gerrits, Miriam; Wenninger, Jochen; Gonzalez-Angarita, Adriana; Savenije, Hubert

doi:10.5194/hess-24-2179-2020

Cited by 15 publications

(14 citation statements)

References 108 publications

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“…1). Overstory stemflow is currently assumed to bypass the understory and litter layers (Carlyle-Moses et al, 2018); however, this assumption, particularly regarding the bypass of litter, has rarely been tested , and overstory stemflow has been observed to runoff for long distances away from the stem (Cattan et al, 2009;Keen et al, 2010). We do not investigate interactions between the understory and overstory stemflow in this study, because stemflow from this study site is negligible (< 0.2 %: Yankine et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Rainfall interception and redistribution by a common North American understory and pasture forb, <i>Eupatorium capillifolium</i> (Lam. dogfennel)

Gordon

Coenders-Gerrits

Sellers

et al. 2020

Hydrol. Earth Syst. Sci.

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Abstract. In vegetated landscapes, rain must pass through plant canopies and litter to enter soils. As a result, some rainwater is returned to the atmosphere (i.e., interception, I) and the remainder is partitioned into a canopy (and gap) drip flux (i.e., throughfall) or drained down the stem (i.e., stemflow). Current theoretical and numerical modeling frameworks for this process are almost exclusively based on data from woody overstory plants. However, herbaceous plants often populate the understory and are the primary cover for important ecosystems (e.g., grasslands and croplands). This study investigates how overstory throughfall (PT,o) is partitioned into understory I, throughfall (PT) and stemflow (PS) by a dominant forb in disturbed urban forests (as well as grasslands and pasturelands), Eupatorium capillifolium (Lam., dogfennel). Dogfennel density at the site was 56 770 stems ha−1, enabling water storage capacities for leaves and stems of 0.90±0.04 and 0.43±0.02 mm, respectively. As direct measurement of PT,o (using methods such as tipping buckets or bottles) would remove PT,o or disturb the understory partitioning of PT,o, overstory throughfall was modeled (PT,o′) using on-site observations of PT,o from a previous field campaign. Relying on modeled PT,o′, rather than on observations of PT,o directly above individual plants means that significant uncertainty remains with respect to (i) small-scale relative values of PT and PS and (ii) factors driving PS variability among individual dogfennel plants. Indeed, PS data from individual plants were highly skewed, where the mean PS:PT,o′ per plant was 36.8 %, but the median was 7.6 % (2.8 %–27.2 % interquartile range) and the total over the study period was 7.9 %. PS variability (n=30 plants) was high (CV > 200 %) and may hypothetically be explained by fine-scale spatiotemporal patterns in actual overstory throughfall (as no plant structural factors explained the variability). The total PT:PT,o′ was 71 % (median PT:PT,o′ per gauge was 72 %, with a 59 %–91 % interquartile range). Occult precipitation (mixed dew and light rain events) occurred during the study period, revealing that dogfennel can capture and drain dew to their stem base as PS. Dew-induced PS may help explain dogfennel's improved invasion efficacy during droughts (as it tends to be one of the most problematic weeds in the improved grazing systems in the southeastern US). Overall, dogfennel's precipitation partitioning differed markedly from the site's overstory trees (Pinus palustris), and a discussion of the limited literature suggests that these differences may exist across vegetated ecosystems. Thus, more research on herbaceous plant canopy interactions with precipitation is merited.

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Section: Introductionmentioning

confidence: 99%

Rainfall interception and redistribution by a common North American understory and pasture forb, <i>Eupatorium capillifolium</i> (Lam. dogfennel)

Gordon

Coenders-Gerrits

Sellers

et al. 2020

Hydrol. Earth Syst. Sci.

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“…In recent decades, remote sensing ET retrieval based on the combination of satellite re-Z. Liu: The accuracy of temporal upscaling of instantaneous evapotranspiration mote sensing data and the land surface energy model has become an increasingly important area of research, as it can represent the spatial heterogeneity of terrestrial ET at regional or global scales (Jung et al, 2010;Miralles et al, 2011;Mu et al, 2011;Zhang et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

The accuracy of temporal upscaling of instantaneous evapotranspiration to daily values with seven upscaling methods

Liu

2021

Hydrol. Earth Syst. Sci.

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Abstract. This study evaluated the accuracy of seven upscaling methods in simulating daily latent heat flux (LE) from instantaneous values using observations from 148 global sites under all sky conditions and at different times during the day. Daily atmospheric transmissivity (τ) was used to represent the sky conditions. The results showed that all seven methods could accurately simulate daily LE from instantaneous values. The mean and median of Nash–Sutcliffe efficiency were 0.80 and 0.85, respectively, and the corresponding determination coefficients were 0.87 and 0.90, respectively. The sine and Gaussian function methods simulated mean values with relatively higher accuracy, with relative errors generally within ±10 %. The evaporative fraction (EF) methods, which use potential evapotranspiration and incoming shortwave radiation, performed relatively better than the other methods in simulating daily series. Overall, the EF method using potential evapotranspiration had the highest accuracy. However, the sine function and the EF method using extraterrestrial solar irradiance are recommended in upscaling applications because of the relatively minimal data requirements of these methods and their comparable or relatively higher accuracy. The intra-day distribution of the LE showed greater consistency with the Gaussian function than the sine function. However, the accuracy of simulated daily LE series using the Gaussian function method did not improve significantly compared with the sine function method. The simulation accuracy showed a minor difference when using the same type of method, for example, the same type of mathematical function or EF method. In any upscaling scheme, the simulation accuracy from multi-time values was significantly higher than that from a single-time value. Therefore, when multi-time data are available, multi-time values should be used in evapotranspiration upscaling. The upscaling methods show the ability to accurately simulate daily LE from instantaneous values from 09:00 to 15:00, particularly for instantaneous values between 11:00 and 14:00. However, outside of this time range the upscaling methods performed poorly. These methods can simulate daily LE series with high accuracy at τ > 0.6; when τ < 0.6, simulation accuracy is significantly affected by sky conditions and is generally positively related to daily atmospheric transmissivity. Although every upscaling scheme can accurately simulate daily LE from instantaneous values at most sites, this ability is lost at tropical rainforest and tropical monsoon sites.

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“…The annual mean temperature is 26.3°C and temperatures vary between ca. 20 and 30°C all year (Jiménez‐Rodríguez et al, 2020). The mean annual precipitation is 4350 mm (mean of 54 years), with a bimodal rainfall seasonality.…”

Section: Methodsmentioning

confidence: 99%

Simulating climate changein situin a tropical rainforest understorey using active air warming and CO₂addition

Bader

Moureau

Nikolić

et al. 2022

Ecology and Evolution

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Future climate‐change effects on plant growth are most effectively studied using microclimate‐manipulation experiments, the design of which has seen much advance in recent years. For tropical forests, however, such experiments are particularly hard to install and have hence not been widely used. We present a system of active heating and CO2 fertilization for use in tropical forest understoreys, where passive heating is not possible. The system was run for 2 years to study climate‐change effects on epiphytic bryophytes, but is also deemed suitable to study other understorey plants. Warm air and CO2 addition were applied in 1.6‐m‐tall, 1.2‐m‐diameter hexagonal open‐top chambers and the microclimate in the chambers compared to outside air. Warming was regulated with a feedback system while CO2 addition was fixed. The setup successfully heated the air by 2.8 K and increased CO2 by 250 ppm on average, with +3 K and +300 ppm as the targets. Variation was high, especially due to technical breakdowns, but not biased to times of the day or year. In the warming treatment, absolute humidity slightly increased but relative humidity dropped by between 6% and 15% (and the vapor pressure deficit increased) compared to ambient, depending on the level of warming achieved in each chamber. Compared to other heating systems, the chambers provide a realistic warming and CO2 treatment, but moistening the incoming air would be needed to avoid drying as a confounding factor. The method is preferable over infrared heating in the radiation‐poor forest understorey, particularly when combined with CO2 fertilization. It is suitable for plant‐level studies, but ecosystem‐level studies in forests may require chamber‐less approaches like infrared heating and free‐air CO2 enrichment. By presenting the advantages and limitations of our approach, we aim to facilitate further climate‐change experiments in tropical forests, which are urgently needed to understand the processes determining future element fluxes and biodiversity changes in these ecosystems.

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Contribution of understory evaporation in a tropical wet forest during the dry season

Cited by 15 publications

References 108 publications

Rainfall interception and redistribution by a common North American understory and pasture forb, <i>Eupatorium capillifolium</i> (Lam. dogfennel)

Rainfall interception and redistribution by a common North American understory and pasture forb, <i>Eupatorium capillifolium</i> (Lam. dogfennel)

The accuracy of temporal upscaling of instantaneous evapotranspiration to daily values with seven upscaling methods

Simulating climate changein situin a tropical rainforest understorey using active air warming and CO₂addition

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Contribution of understory evaporation in a tropical wet forest during the dry season

Cited by 15 publications

References 108 publications

Rainfall interception and redistribution by a common North American understory and pasture forb, &lt;i&gt;Eupatorium capillifolium&lt;/i&gt; (Lam. dogfennel)

Rainfall interception and redistribution by a common North American understory and pasture forb, &lt;i&gt;Eupatorium capillifolium&lt;/i&gt; (Lam. dogfennel)

The accuracy of temporal upscaling of instantaneous evapotranspiration to daily values with seven upscaling methods

Simulating climate changein situin a tropical rainforest understorey using active air warming and CO2addition

Contact Info

Product

Resources

About

Rainfall interception and redistribution by a common North American understory and pasture forb, <i>Eupatorium capillifolium</i> (Lam. dogfennel)

Rainfall interception and redistribution by a common North American understory and pasture forb, <i>Eupatorium capillifolium</i> (Lam. dogfennel)

Simulating climate changein situin a tropical rainforest understorey using active air warming and CO₂addition