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Dr. Miriam Coenders
TU Delft, department of civil engineering and geosciences

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0 Evaporation
0 Forest
0 transpiration
0 interception
0 DTS

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Preprint content
Published: 09 July 2021
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Thornthwaite’s formula is globally an optimum candidate for large scale applications of potential evapotranspiration and aridity assessment at different climates and landscapes since it has the lower data requirements compared to other methods and especially from the ASCE-standardized reference evapotranspiration (former FAO-56), which is the most data demanding method and is commonly used as benchmark method. The aim of the study is to develop a global database of local coefficients for correcting the formula of monthly Thornthwaite potential evapotranspiration (Ep) using as benchmark the ASCE-standardized reference evapotranspiration method (Er). The validity of the database will be verified by testing the hypothesis that a local correction coefficient, which integrates the local mean effect of wind speed, humidity and solar radiation, can improve the performance of the original Thornthwaite formula. The database of local correction coefficients was developed using global gridded temperature and Er data of the period 1950–2000 at 30 arc-sec resolution (~1 km at equator) from freely available climate geodatabases. The correction coefficients were produced as partial weighted averages of monthly Er / Ep ratios by setting the ratios’ weight according to the monthly Er magnitude and by excluding colder months with monthly values of Er or Ep < 45 mm month−1 because their ratio becomes highly unstable for low temperatures. The validation of the correction coefficients was made using raw data from 525 stations of Europe, California-USA and Australia including data up to 2020. The validation procedure showed that the corrected Thornthwaite formula Eps using local coefficients led to a reduction of RMSE from 37.2 to 30.0 mm m−1 for monthly and from 388.8 to 174.8 mm y−1 for annual step estimations compared to Ep using as benchmark the values of Er method. The corrected Eps and the original Ep Thornthwaite formulas were also evaluated by their use in Thornthwaite and UNEP (United Nations Environment Program) aridity indices using as benchmark the respective indices estimated by Er. The analysis was made using the validation data of the stations and the results showed that the correction of Thornthwaite formula using local coefficients increased the accuracy of detecting identical aridity classes with Er from 63 % to 76 % for the case of Thornthwaite classification, and from 76 % to 93 % for the case of UNEP classification. The performance of both aridity indices using the corrected formula was extremely improved in the case of non-humid classes. The global database of local correction factors can support applications of reference evapotranspiration and aridity indices assessment with the minimum data requirements (i.e. temperature) for locations where climatic data are limited. The global grids of local correction coefficients for Thornthwaite formula produced in this study are archived in PANGAEA database andcan be assessed using the following link: https://doi.pangaea.de/10.1594/PANGAEA.932638 (Aschonitis et al., 2021).

ACS Style

Vassilis Aschonitis; Dimos Touloumidis; Marie-Claire Ten Veldhuis; Miriam Coenders-Gerrits. Correcting Thornthwaite potential evapotranspiration using a global grid of local coefficients to support temperature-based estimations of reference evapotranspiration and aridity indices. 2021, 2021, 1 -25.

AMA Style

Vassilis Aschonitis, Dimos Touloumidis, Marie-Claire Ten Veldhuis, Miriam Coenders-Gerrits. Correcting Thornthwaite potential evapotranspiration using a global grid of local coefficients to support temperature-based estimations of reference evapotranspiration and aridity indices. . 2021; 2021 ():1-25.

Chicago/Turabian Style

Vassilis Aschonitis; Dimos Touloumidis; Marie-Claire Ten Veldhuis; Miriam Coenders-Gerrits. 2021. "Correcting Thornthwaite potential evapotranspiration using a global grid of local coefficients to support temperature-based estimations of reference evapotranspiration and aridity indices." 2021, no. : 1-25.

Preprint content
Published: 09 July 2021
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ACS Style

Vassilis Aschonitis; Dimos Touloumidis; Marie-Claire Ten Veldhuis; Miriam Coenders-Gerrits. Supplementary material to "Correcting Thornthwaite potential evapotranspiration using a global grid of local coefficients to support temperature-based estimations of reference evapotranspiration and aridity indices". 2021, 1 .

AMA Style

Vassilis Aschonitis, Dimos Touloumidis, Marie-Claire Ten Veldhuis, Miriam Coenders-Gerrits. Supplementary material to "Correcting Thornthwaite potential evapotranspiration using a global grid of local coefficients to support temperature-based estimations of reference evapotranspiration and aridity indices". . 2021; ():1.

Chicago/Turabian Style

Vassilis Aschonitis; Dimos Touloumidis; Marie-Claire Ten Veldhuis; Miriam Coenders-Gerrits. 2021. "Supplementary material to "Correcting Thornthwaite potential evapotranspiration using a global grid of local coefficients to support temperature-based estimations of reference evapotranspiration and aridity indices"." , no. : 1.

Preprint content
Published: 04 March 2021
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The interception process is an important redistributor of water fluxes, which can considerably affect terrestrial evaporation. Not only the canopy intercepts water, but also from the forest floor significant amounts of water vapor return to the atmosphere. Remaining forests are important areas to evaluate the possible effects of climate change on the water partitioning process. Despite the hydrologic and ecosystem services offered by Cerrado forests, the interception process, as well as climate change threats on the evaporative flux of such forests, are still unknown. This study attempts to anticipate the possible impacts on the forest floor interception process in Cerrado stricto sensu considering future scenarios of climate change. To accomplish this, we used data of field monitoring from June 2017 to February 2020 in an undisturbed Cerrado s.s. forest in São Paulo State, Brazil. We calibrated and validated an improved version of the Rutter interception model (Rutter et al., 1971), which includes interception from the forest floor. Projected climate change scenarios were obtained from the National Institute for Space Research (INPE, Brazil) from 2006 to 2099 with 5km spatial resolution generated by Eta-HadGEM2-ES regional climate model under representative concentration pathway (RCP) 4.5. The results indicate increased rainfall and decreased potential evaporation in the decade 2041-2060. By the Rutter model, the total interception increased for this period (2041-2060) associated with decreased forest floor evaporation. During the first (2006-2020) and the last (2081-2099) decades, the predictions suggest an increase of 2.4% on the average annual percentage of forest floor evaporation, also an increase of minimum annual interception percentages (from 17.1% to 18.7%). Thus, our results demonstrate the relevance of forest floor to the interception process and suggest that it can be even more relevant in the future due to the climate changes.

ACS Style

Livia Rosalem; Miriam Gerrits-Coenders; Jamil A. A. Anache; Julian S. Sone; Dimaghi Schwamback; Alessandra Campos; Edson Wendland. Climate change effects on forest floor interception in woody Cerrado ecosystem. 2021, 1 .

AMA Style

Livia Rosalem, Miriam Gerrits-Coenders, Jamil A. A. Anache, Julian S. Sone, Dimaghi Schwamback, Alessandra Campos, Edson Wendland. Climate change effects on forest floor interception in woody Cerrado ecosystem. . 2021; ():1.

Chicago/Turabian Style

Livia Rosalem; Miriam Gerrits-Coenders; Jamil A. A. Anache; Julian S. Sone; Dimaghi Schwamback; Alessandra Campos; Edson Wendland. 2021. "Climate change effects on forest floor interception in woody Cerrado ecosystem." , no. : 1.

Journal article
Published: 11 February 2021 in Hydrology and Earth System Sciences
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Forest evaporation exports a vast amount of water vapor from land ecosystems into the atmosphere. Meanwhile, evaporation during rain events is neglected or considered of minor importance in dense ecosystems. Air convection moves the water vapor upwards leading to the formation of large invisible vapor plumes, while the identification of visible vapor plumes has not yet been studied. This work describes the formation process of vapor plumes in a tropical wet forest as evidence of evaporation processes happening during rain events. In the dry season of 2018 at La Selva Biological Station (LSBS) in Costa Rica it was possible to spot visible vapor plumes within the forest canopy. The combination of time-lapse videos at the canopy top with conventional meteorological measurements along the canopy profile allowed us to identify the driver conditions required for this process to happen. This phenomenon happened only during rain events. Visible vapor plumes during the daytime occurred when the following three conditions are accomplished: presence of precipitation (P), air convection, and a lifting condensation level value smaller than 100 m at 43 m height (zlcl.43).

ACS Style

César Dionisio Jiménez-Rodríguez; Miriam Coenders-Gerrits; Bart Schilperoort; Adriana Del Pilar González-Angarita; Hubert Savenije. Vapor plumes in a tropical wet forest: spotting the invisible evaporation. Hydrology and Earth System Sciences 2021, 25, 619 -635.

AMA Style

César Dionisio Jiménez-Rodríguez, Miriam Coenders-Gerrits, Bart Schilperoort, Adriana Del Pilar González-Angarita, Hubert Savenije. Vapor plumes in a tropical wet forest: spotting the invisible evaporation. Hydrology and Earth System Sciences. 2021; 25 (2):619-635.

Chicago/Turabian Style

César Dionisio Jiménez-Rodríguez; Miriam Coenders-Gerrits; Bart Schilperoort; Adriana Del Pilar González-Angarita; Hubert Savenije. 2021. "Vapor plumes in a tropical wet forest: spotting the invisible evaporation." Hydrology and Earth System Sciences 25, no. 2: 619-635.

Journal article
Published: 21 December 2020 in Biogeosciences
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Complex ecosystems such as forests make accurately measuring atmospheric energy and matter fluxes difficult. One of the issues that can arise is that parts of the canopy and overlying atmosphere can be turbulently decoupled from each other, meaning that the vertical exchange of energy and matter is reduced or hampered. This complicates flux measurements performed above the canopy. Wind above the canopy will induce vertical exchange. However, stable thermal stratification, when lower parts of the canopy are colder, will hamper vertical exchange. To study the effect of thermal stratification on decoupling, we analyze high-resolution (0.3 m) vertical temperature profiles measured in a Douglas fir stand in the Netherlands using distributed temperature sensing (DTS). The forest has an open understory (0–20 m) and a dense overstory (20–34 m). The understory was often colder than the atmosphere above (80 % of the time during the night, >99 % during the day). Based on the aerodynamic Richardson number the canopy was regularly decoupled from the atmosphere (50 % of the time at night). In particular, decoupling could occur when both u*

ACS Style

Bart Schilperoort; Miriam Coenders-Gerrits; César Jiménez Rodríguez; Christiaan Van Der Tol; Bas Van De Wiel; Hubert Savenije. Decoupling of a Douglas fir canopy: a look into the subcanopy with continuous vertical temperature profiles. Biogeosciences 2020, 17, 6423 -6439.

AMA Style

Bart Schilperoort, Miriam Coenders-Gerrits, César Jiménez Rodríguez, Christiaan Van Der Tol, Bas Van De Wiel, Hubert Savenije. Decoupling of a Douglas fir canopy: a look into the subcanopy with continuous vertical temperature profiles. Biogeosciences. 2020; 17 (24):6423-6439.

Chicago/Turabian Style

Bart Schilperoort; Miriam Coenders-Gerrits; César Jiménez Rodríguez; Christiaan Van Der Tol; Bas Van De Wiel; Hubert Savenije. 2020. "Decoupling of a Douglas fir canopy: a look into the subcanopy with continuous vertical temperature profiles." Biogeosciences 17, no. 24: 6423-6439.

Journal article
Published: 13 October 2020 in Atmospheric Measurement Techniques
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Near-surface wind speed is typically only measured by point observations. The actively heated fiber-optic (AHFO) technique, however, has the potential to provide high-resolution distributed observations of wind speeds, allowing for better spatial characterization of fine-scale processes. Before AHFO can be widely used, its performance needs to be tested in a range of settings. In this work, experimental results on this novel observational wind-probing technique are presented. We utilized a controlled wind tunnel setup to assess both the accuracy and the precision of AHFO under a range of operational conditions (wind speed, angles of attack and temperature difference). The technique allows for wind speed characterization with a spatial resolution of 0.3 m on a 1 s timescale. The flow in the wind tunnel was varied in a controlled manner such that the mean wind ranged between 1 and 17 m s−1. The AHFO measurements are compared to sonic anemometer measurements and show a high coefficient of determination (0.92–0.96) for all individual angles, after correcting the AHFO measurements for the angle of attack. Both the precision and accuracy of the AHFO measurements were also greater than 95 % for all conditions. We conclude that AHFO has the potential to measure wind speed, and we present a method to help choose the heating settings of AHFO. AHFO allows for the characterization of spatially varying fields of mean wind. In the future, the technique could potentially be combined with conventional distributed temperature sensing (DTS) for sensible heat flux estimation in micrometeorological and hydrological applications.

ACS Style

Justus G. V. Van Ramshorst; Miriam Coenders-Gerrits; Bart Schilperoort; Bas J. H. Van De Wiel; Jonathan G. Izett; John S. Selker; Chad W. Higgins; Hubert H. G. Savenije; Nick C. Van De Giesen. Revisiting wind speed measurements using actively heated fiber optics: a wind tunnel study. Atmospheric Measurement Techniques 2020, 13, 5423 -5439.

AMA Style

Justus G. V. Van Ramshorst, Miriam Coenders-Gerrits, Bart Schilperoort, Bas J. H. Van De Wiel, Jonathan G. Izett, John S. Selker, Chad W. Higgins, Hubert H. G. Savenije, Nick C. Van De Giesen. Revisiting wind speed measurements using actively heated fiber optics: a wind tunnel study. Atmospheric Measurement Techniques. 2020; 13 (10):5423-5439.

Chicago/Turabian Style

Justus G. V. Van Ramshorst; Miriam Coenders-Gerrits; Bart Schilperoort; Bas J. H. Van De Wiel; Jonathan G. Izett; John S. Selker; Chad W. Higgins; Hubert H. G. Savenije; Nick C. Van De Giesen. 2020. "Revisiting wind speed measurements using actively heated fiber optics: a wind tunnel study." Atmospheric Measurement Techniques 13, no. 10: 5423-5439.

Journal article
Published: 22 September 2020 in Hydrology and Earth System Sciences
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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.

ACS Style

D. Alex R. Gordon; Miriam Coenders-Gerrits; Brent A. Sellers; S. M. Moein Sadeghi; John T. Van Stan Ii. Rainfall interception and redistribution by a common North American understory and pasture forb, Eupatorium capillifolium (Lam. dogfennel). Hydrology and Earth System Sciences 2020, 24, 4587 -4599.

AMA Style

D. Alex R. Gordon, Miriam Coenders-Gerrits, Brent A. Sellers, S. M. Moein Sadeghi, John T. Van Stan Ii. Rainfall interception and redistribution by a common North American understory and pasture forb, Eupatorium capillifolium (Lam. dogfennel). Hydrology and Earth System Sciences. 2020; 24 (9):4587-4599.

Chicago/Turabian Style

D. Alex R. Gordon; Miriam Coenders-Gerrits; Brent A. Sellers; S. M. Moein Sadeghi; John T. Van Stan Ii. 2020. "Rainfall interception and redistribution by a common North American understory and pasture forb, Eupatorium capillifolium (Lam. dogfennel)." Hydrology and Earth System Sciences 24, no. 9: 4587-4599.

Journal article
Published: 16 August 2020 in Hydrology
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Understanding the canopy cover relationship with canopy water content and canopy temperature in the Miombo ecosystem is important for studying the consequences of climate change. To better understand these relationships, we studied the satellite data-based land surface temperature (LST) as proxy for canopy temperature, leaf area index (LAI), and the normalized difference vegetation index (NDVI) as proxies for canopy cover. Meanwhile, the normalized difference infrared index (NDII) was used as a proxy for canopy water content. We used several statistical approaches including the correlated component regression linear model (CCR.LM) to understand the relationships. Our results showed that the most determinant factor of variations in the canopy cover was the interaction between canopy water content (i.e., NDII) and canopy temperature (i.e., LST) with coefficients of determination (R2) ranging between 0.67 and 0.96. However, the coefficients of estimates showed the canopy water content (i.e., NDII) to have had the largest percentage of the interactive effect on the variations in canopy cover regardless of the proxy used i.e., LAI or NDVI. From 2009–2018, the NDII (proxy for canopy water content) showed no significant (at alpha level 0.05) trend. However, there was a-n significant upward trend in LST (proxy for canopy temperature) with a magnitude of 0.17 °C/year. Yet, the upward trend in LST did not result in significant (at alpha level 0.05) downward changes in canopy cover (i.e., proxied by LAI and NDVI). This result augments the observed least determinant factor characterization of temperature (i.e., LST) on the variations in canopy cover as compared to the vegetation water content (i.e., NDII).

ACS Style

Henry Zimba; Miriam Coenders-Gerrits; Banda Kawawa; Hubert Savenije; Imasiku Nyambe; Hessel Winsemius. Variations in Canopy Cover and Its Relationship with Canopy Water and Temperature in the Miombo Woodland Based on Satellite Data. Hydrology 2020, 7, 58 .

AMA Style

Henry Zimba, Miriam Coenders-Gerrits, Banda Kawawa, Hubert Savenije, Imasiku Nyambe, Hessel Winsemius. Variations in Canopy Cover and Its Relationship with Canopy Water and Temperature in the Miombo Woodland Based on Satellite Data. Hydrology. 2020; 7 (3):58.

Chicago/Turabian Style

Henry Zimba; Miriam Coenders-Gerrits; Banda Kawawa; Hubert Savenije; Imasiku Nyambe; Hessel Winsemius. 2020. "Variations in Canopy Cover and Its Relationship with Canopy Water and Temperature in the Miombo Woodland Based on Satellite Data." Hydrology 7, no. 3: 58.

Preprint content
Published: 24 June 2020
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Complex ecosystems such as forests make accurately measuring atmospheric energy and matter fluxes difficult. One of the issues that can arise is that parts of the canopy and overlying atmosphere can be turbulently decoupled from each other, meaning that the vertical exchange of energy and matter is reduced or hampered. This complicates flux measurements performed above the canopy. Wind above the canopy will induce vertical exchange. However, stable thermal stratification, when lower parts of the canopy are colder, will hamper vertical exchange. To study the effect of thermal stratification on decoupling, we analyze high resolution (0.3 m) vertical temperature profiles measured in a Douglas fir stand in the Netherlands using Distributed Temperature Sensing (DTS). The forest has an open understory (0–20 m) and a dense overstory (20–34 m). The understory was often colder than the atmosphere above (80 % of the time during the night, > 99 % during the day), and was regularly decoupled from the atmosphere (50 % of the time at night). The relationship between the temperature gradients and the friction velocity (u*) showed a clear threshold between coupling regimes. In particular, decoupling occurred when u*

ACS Style

Bart Schilperoort; Miriam Coenders-Gerrits; César Jiménez Rodríguez; Christiaan Van Der Tol; Bas Van De Wiel; Hubert Savenije. Decoupling of a Douglas fir canopy: a look into the subcanopy with continuous vertical temperature profiles. 2020, 2020, 1 -25.

AMA Style

Bart Schilperoort, Miriam Coenders-Gerrits, César Jiménez Rodríguez, Christiaan Van Der Tol, Bas Van De Wiel, Hubert Savenije. Decoupling of a Douglas fir canopy: a look into the subcanopy with continuous vertical temperature profiles. . 2020; 2020 ():1-25.

Chicago/Turabian Style

Bart Schilperoort; Miriam Coenders-Gerrits; César Jiménez Rodríguez; Christiaan Van Der Tol; Bas Van De Wiel; Hubert Savenije. 2020. "Decoupling of a Douglas fir canopy: a look into the subcanopy with continuous vertical temperature profiles." 2020, no. : 1-25.

Preprint content
Published: 22 June 2020
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Deforestation can considerably affect transpiration dynamics and magnitudes at the catchment-scale and thereby alter the partitioning between drainage and evaporative water fluxes released from terrestrial hydrological systems. However, it has so far remained problematic to directly link reductions in transpiration to changes in the physical properties of the system and to quantify these changes of system properties at the catchment-scale. As a consequence, it is difficult to quantify the effect of deforestation on parameters of catchment-scale hydrological models. This in turn leads to substantial uncertainties in predictions of the hydrological response after deforestation but also to a poor understanding of how deforestation affects principal descriptors of catchment-scale transport, such as travel time distributions and young water fractions. The objectives of this study are therefore to quantify the effects of deforestation in the Wüstebach experimental catchment on the partitioning of water fluxes and to directly associate these changes to changes in parameters of a hydrological model with integrated tracer routine based on the concept of storage age selection functions. Simultaneously modelling stream flow and stable water isotope dynamics using meaningfully adjusted model parameters both for the pre- and post-deforestation periods, respectively, the model is used to track fluxes through the system and to estimate the effects of deforestation on catchment travel time distributions and young water fractions Fyw. It was found that deforestation led to a significant increase of stream flow, accompanied by corresponding reductions of evaporative fluxes. This is reflected by an increase of the runoff ratio from CR = 0.55 to 0.68 in the post-deforestation period despite similar climatic conditions. This reduction of evaporative fluxes could be linked to a reduction of the catchment-scale water storage volume in the unsaturated soil (SU,max) that is within the reach of active roots and thus accessible for vegetation transpiration from ~ 225 mm in the pre-deforestation period to ~ 90 mm in the post-deforestations period. The hydrological model, reflecting the changes in the parameter SU,max indicated that in the post-deforestation period stream water was characterized by slightly higher mean fractions of young water (Fyw ~ 0.13) than in the pre-deforestation period (Fyw ~ 0.11). In spite of these limited effects on the overall Fyw, considerable changes were found for wet periods, during which post-deforestation fractions of young water increased to values Fyw ~ 0.40 for individual storms. Deforestation also caused a significantly increased sensitivity of young water fractions to discharge under wet conditions from dFyw/dQ = 0.25 to 0.43. Overall, this study demonstrates that deforestation has not only the potential to affect the partitioning between drainage and evaporation as well as the vegetation-accessible storage volumes SU,max, and thus the fundamental hydrological response characteristics of catchments, but also catchment-scale tracer circulation dynamics. In particular for wet conditions, deforestation caused higher proportions of younger water to reach the stream, implying faster routing of stable isotopes and plausibly also solutes through the subsurface.

ACS Style

Markus Hrachowitz; Michael Stockinger; Miriam Coenders-Gerrits; Ruud Van Der Ent; Heye Bogena; Andreas Lücke; Christine Stumpp. Deforestation reduces the vegetation-accessible water storage in the unsaturated soil and affects catchment travel time distributions and young water fractions. 2020, 2020, 1 -43.

AMA Style

Markus Hrachowitz, Michael Stockinger, Miriam Coenders-Gerrits, Ruud Van Der Ent, Heye Bogena, Andreas Lücke, Christine Stumpp. Deforestation reduces the vegetation-accessible water storage in the unsaturated soil and affects catchment travel time distributions and young water fractions. . 2020; 2020 ():1-43.

Chicago/Turabian Style

Markus Hrachowitz; Michael Stockinger; Miriam Coenders-Gerrits; Ruud Van Der Ent; Heye Bogena; Andreas Lücke; Christine Stumpp. 2020. "Deforestation reduces the vegetation-accessible water storage in the unsaturated soil and affects catchment travel time distributions and young water fractions." 2020, no. : 1-43.

Review article
Published: 29 May 2020 in Journal of Hydrology
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The Budyko framework was firstly developed to estimate actual evaporation as a function of precipitation and the aridity index at steady state conditions. Based on this framework, the water storage change in the watershed is assumed to be negligible at large spatial and temporal scales. However, steady state conditions are not valid for many watersheds worldwide or at finer temporal or spatial scales. Accordingly, the application of the Budyko framework has become challenging for these situations. Therefore, many researchers have tried to extend the Budyko framework for non-steady state conditions. The aim of this study is to provide a review of the extended equations and to discuss using the Budyko framework in a changing world. While the extended equations are more complex than the original ones, they still require little data. Thus, the Budyko framework, either the original or the extended can be a very useful tool for hydrological modeling with lots of applications, especially in data scarce regions.

ACS Style

Ameneh Mianabadi; Kamran Davary; Mohsen Pourreza-Bilondi; A.M.J. Coenders-Gerrits. Budyko framework; towards non-steady state conditions. Journal of Hydrology 2020, 588, 125089 .

AMA Style

Ameneh Mianabadi, Kamran Davary, Mohsen Pourreza-Bilondi, A.M.J. Coenders-Gerrits. Budyko framework; towards non-steady state conditions. Journal of Hydrology. 2020; 588 ():125089.

Chicago/Turabian Style

Ameneh Mianabadi; Kamran Davary; Mohsen Pourreza-Bilondi; A.M.J. Coenders-Gerrits. 2020. "Budyko framework; towards non-steady state conditions." Journal of Hydrology 588, no. : 125089.

Journal article
Published: 30 April 2020 in Hydrology and Earth System Sciences
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Tropical wet forests are complex ecosystems with a large number of plant species. These environments are characterized by a high water availability throughout the whole year and a complex canopy structure. However, how the different sections of the canopy contribute to total evaporation is poorly understood. The aim of this work is to estimate the total evaporation flux and differentiate the contribution among canopy layers of a tropical wet forest in Costa Rica. The fluxes were monitored during the dry season by making use of the energy balance to quantify the fluxes and stable water isotopes to trace the sources of water vapor. Total evaporation was 275.5 mm and represents 55.9 % of the recorded precipitation (498.8 mm), with 11.7 % of the precipitation being intercepted and evaporated along the forest canopy. The understory beneath 8 m contributed 23.6 % of the evaporation, and almost half of it comes from the first 2 m of the understory. Stable water isotope signatures show different soil water sources depending on the plant type. Palms make use of a water source with an isotope signature similar to precipitation and throughfall. Soil water with a fractionated signature is used by trees, bushes and lianas. The isotope signature of water vapor samples overlap among different heights, but it was not possible to make use of the Keeling plot method due to the similar isotope signature of the possible sources of water vapor as well as the high water concentration even on the dryer days.

ACS Style

César Dionisio Jiménez-Rodríguez; Miriam Coenders-Gerrits; Jochen Wenninger; Adriana Gonzalez-Angarita; Hubert Savenije. Contribution of understory evaporation in a tropical wet forest during the dry season. Hydrology and Earth System Sciences 2020, 24, 2179 -2206.

AMA Style

César Dionisio Jiménez-Rodríguez, Miriam Coenders-Gerrits, Jochen Wenninger, Adriana Gonzalez-Angarita, Hubert Savenije. Contribution of understory evaporation in a tropical wet forest during the dry season. Hydrology and Earth System Sciences. 2020; 24 (4):2179-2206.

Chicago/Turabian Style

César Dionisio Jiménez-Rodríguez; Miriam Coenders-Gerrits; Jochen Wenninger; Adriana Gonzalez-Angarita; Hubert Savenije. 2020. "Contribution of understory evaporation in a tropical wet forest during the dry season." Hydrology and Earth System Sciences 24, no. 4: 2179-2206.

Preprint content
Published: 23 March 2020
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One of the challenges of flux measurements above tall canopies, is that parts of the canopy can be decoupled from the atmosphere above. This decoupling can, for example, occur when the forest understory is colder than the air above, limiting exchange through convection. While concurrent above and below canopy eddy covariance (EC) measurements help with addressing the decoupling issue, these are still disconnected point measurements and do not show what is happening along the entire vertical profile. For this, Distributed Temperature Sensing (DTS) can give additional insights, as it can perform continuous temperature measurements along a vertically deployed fiber optic cable.

Measurements were performed at the ‘Speulderbos’ forest site in the Netherlands, where a 48 m tall measurement tower is located in a stand of 34 m tall Douglas Fir trees.  We measured a vertical temperature profile through the canopy using DTS (from the surface up to 32 m). The measurement frequency was ~0.5 Hz, with a vertical resolution 0.30 cm, and data was collected for two months. The fiber optic cable used had a diameter of 0.8 mm, allowing a sufficiently quick response to temperature changes. With this data we were able to detect the presence, height, and strength of inversions. The inversions appeared to occur mostly at night. The height of the inversion showed a bistable behavior, either staying around 1 m above the ground, or at approximately 16 m, which is just below the dense branches of the canopy.

By locating and tracking inversions within the canopy, decoupling events can be studied and explained in more detail. If vertical DTS profiles are available at a site, these can be used for filtering EC measurements as well. While more research will be needed before a wide application at flux sites is possible, this study can serve as a ‘proof-of-concept’ and demonstrates how vertical DTS profiles can help understand problematic flux sites.

ACS Style

Bart Schilperoort; Miriam Coenders-Gerrits; Hubert Savenije. Measuring and tracking nighttime inversions within a forest canopy. 2020, 1 .

AMA Style

Bart Schilperoort, Miriam Coenders-Gerrits, Hubert Savenije. Measuring and tracking nighttime inversions within a forest canopy. . 2020; ():1.

Chicago/Turabian Style

Bart Schilperoort; Miriam Coenders-Gerrits; Hubert Savenije. 2020. "Measuring and tracking nighttime inversions within a forest canopy." , no. : 1.

Preprint content
Published: 23 March 2020
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Miombo woodland is the most widespread tropical seasonal woodland and dry forest formation in Africa covering between 2.7 and 3.6 million km2 in eleven countries. Leaf fall and leaf flush during the dry season is a major characteristic feature of the various Miombo species. However, the question on what induces the leaf fall process is by far inconclusive. Different studies indicate either moisture or temperature or both elements as inducers for leaf fall. Knowing what induces leaf fall is important for studying the consequence of e.g., climate change on the Miombo forest. To better understand the driver of leaf fall in Miombo forest we employed a simple remote sensing and statistical analysis approach using long term averages (2009 – 2018) of Land Surface Temperature (LST) of the Miombo forest, various vegetation indices (VI), actual evaporation (Ea), and root zone soil moisture (SM). The vegetation indices (VI) included the Normalised Difference Water Index (NDWI) as indicator of vegetation water content and the Normalised Difference Vegetation Index (NDVI) as indicator of plant photosynthetic activities and leaf cover. Results showed that the NDWI, NDVI, Ea and SM begun to decline immediately following the end of the rainy season in early April while the LST remained relatively constant before it began to decline in May when leaf fall in some Miombo species begins. Hysteresis graphs revealed that vegetation water content (i.e. NDWI) responded quicker to changes in both LST and SM. Furthermore, high rates of decrease in NDWI and NDVI values were observed between July and September the same period when LST increased. This is also the same period when leaf fall intensifies in Miombo forest. Correlation analysis revealed strong season-dependent LST relationship with VI and SM with the rainy season exhibiting strong negative linear correlations (R2 = 0.77, 0.91, 0.88; for the NDWI, NDVI and SM respectively). In the dry season relatively weaker negative correlations (R2 = 0.52, 0.60, 0.55; for NDWI, NDVI and SM respectively) were observed. On the other hand SM showed strong positive linear correlations (R2 > 0.6) with NDWI and NDVI (for the rainy and dry seasons respectively). The correlations imply that in Miombo forest soil water content (i.e. SM), vegetation water content (i.e. NDWI) and the photosynthetic activities and leaf cover (i.e. NDVI) declines with increase in LST. These relationships show the possibility of land surface temperature being a major inducing element of leaf fall and changes in canopy structure in the Miombo woodland.

ACS Style

Henry Zimba; Miriam Coenders-Gerrits; Banda Kawawa; Imasiku Nyambe; Hubert Savenije; Hessel Winsemius. Land Surface Temperature and Miombo forest canopy phenophases: what induces leaf fall and leaf flush? 2020, 1 .

AMA Style

Henry Zimba, Miriam Coenders-Gerrits, Banda Kawawa, Imasiku Nyambe, Hubert Savenije, Hessel Winsemius. Land Surface Temperature and Miombo forest canopy phenophases: what induces leaf fall and leaf flush? . 2020; ():1.

Chicago/Turabian Style

Henry Zimba; Miriam Coenders-Gerrits; Banda Kawawa; Imasiku Nyambe; Hubert Savenije; Hessel Winsemius. 2020. "Land Surface Temperature and Miombo forest canopy phenophases: what induces leaf fall and leaf flush?" , no. : 1.

Preprint content
Published: 23 March 2020
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Worldwide 55-80% of the rainfall evaporates from the surface, making it a major water drain for the earth's water resources and a major supply of moisture to the atmosphere. Evaporation is relevant for crop growth and has a high impact on the severity of drought and floods. Nonetheless, this key process is still a highly uncertain, insufficiently quantified process. Also effecting weather forecasts as the available water is used as their boundary condition in atmospheric models. The persistent problem herein is our restricted understanding of the key processes of the land-atmosphere interface, as well as their interplay with hydrological and atmospheric processes. The major bottleneck is the difficulty to properly measure the land-atmosphere interface at the right spatial and temporal scale.

In this talk I will propose an experimental approach that enables data collection for the full surface energy balance at the land-atmosphere interface. This will be achieved by developing and exploiting a 'spider web' - like measurement approach with temperature measuring fibre optic cables (Distributed Temperature Sensing). This will enable simultaneously and continuously measurements of high-resolution temperature, humidity, wind, and soil moisture gradients. Which allows derivaiton of the sensible, latent, and ground heat flux and storage. The spider web offers a better representation of the land-atmosphere interface for the purpose to provide a knowledge base for improving flood and drought predictions and weather forecasts.

ACS Style

Miriam Coenders-Gerrits; Bart Schilperoort. Spider webbing the land-atmosphere interface. 2020, 1 .

AMA Style

Miriam Coenders-Gerrits, Bart Schilperoort. Spider webbing the land-atmosphere interface. . 2020; ():1.

Chicago/Turabian Style

Miriam Coenders-Gerrits; Bart Schilperoort. 2020. "Spider webbing the land-atmosphere interface." , no. : 1.

Preprint content
Published: 23 March 2020
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Determining the water partitioning in the critical zone, and how the biotic and abiotic factors affect these processes, is crucial to improve the comprehension of hydrological processes. Adequate field measurements of water partitioning in forested areas are challenging. Especially, continuous forest litter interception measurements are difficult to obtain. Therefore, we developed an equipment (named Litter Interception Device - LID), composed of a weighting system that contains a load cell with a resolution of 1 g, for continuous measurements of forest litter interception. The study was carried out in a Cerrado woodland forest (Cerrado sensu stricto) since 2017 in the State of São Paulo, Brazil. Following the continuous monitoring, we observed eventual weight gain during the nights. We analyzed the measurements for possible accumulation of dew in two LIDs between August 2018 and August 2019. We first carried out laboratory tests to check the possibility of measurement errors due to temperature shifts on the load cell. A maximum of 3 g error measurement after 10 °C temperature reduction was observed. We also estimated the dew point temperature for the study area during the monitoring period, based on temperature, relative humidity and rainfall data of sensors installed outside the Cerrado’s forest. In the forest, we monitored the temperature using a thermocouple installed in the forest litter sample. All sensors’ data were stored in a datalogger every 10 min. The dataset was analyzed in daily periods between the 9:00 pm and 7:00 am of the subsequent day. To check for dew accumulation on the forest litter, we defined the following minimum criteria to be considered dew, for each interval of our analysis: (a) the total mass gained could not be less than 2 g (equivalent to 0.0125 mm moisture accumulation); (b) the maximum temperature variation on forest litter 7 °C (considering that daily temperature variations close or above 10 ºC could introduce more errors); (c) there was no rainfall from 9:00 pm to 7:00 am of the subsequent day. On 204 days dew point temperature was reached, from which 76 days at least one of the LIDs registered a weight gain. During the study period, the temperature on the forest litter presented a maximum and mean variation of 6.7 °C and 2.5 (±1.2) °C, respectively. The data analysis indicated on average 4.59 mm of dew in one year. This average corresponded to 0.35% of the total rainfall for the study period (1206 mm) and 3.74% of the total average forest litter interception (133 mm). In tropical forests like the wooded Cerrado presented here, rainfall is the major input of water; otherwise to arid regions, were studies have shown that dew is the major input (i.e. Negev Desert). In our case, despite the low percentage related to the total rainfall, dew should not be neglected. As the LID measures all the mass inputs, including forest litter’s deposition, dew must be considered to correctly determine the hydrological processes at different time-space scales.

ACS Style

Livia Rosalem; Jamil A. A. Anache; Miriam Coenders; Edson Wendland. Are dew measurements relevant for forest litter interception on a Cerrado woodland forest? 2020, 1 .

AMA Style

Livia Rosalem, Jamil A. A. Anache, Miriam Coenders, Edson Wendland. Are dew measurements relevant for forest litter interception on a Cerrado woodland forest? . 2020; ():1.

Chicago/Turabian Style

Livia Rosalem; Jamil A. A. Anache; Miriam Coenders; Edson Wendland. 2020. "Are dew measurements relevant for forest litter interception on a Cerrado woodland forest?" , no. : 1.

Journal article
Published: 13 February 2020 in Water
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Accurate estimation of transpiration (Tr) is important in the development of precise irrigation scheduling and to enhance water-use efficiency in agricultural production. In this study, the air temperature (Ta) and relative humidity (RH) were measured at three different heights (0.5, 1.0, and 1.8 m above the ground near the plant canopy) parameterize aerodynamic resistance (ra) based on the heat transfer coefficient method and to estimate Tr using the Stanghellini model (SM) during two growing seasons of cucumber in a greenhouse. The canopy resistance (rc) was parameterized by an exponential relationship of stomata resistance and solar radiation, and the estimated Tr was compared to the values measured with lysimeters. After parameterization of ra and rc, the efficiency (EF) and the Root Mean Square Error (RMSE) of the estimated Tr by the SM based on micrometeorological data at a height of 0.5 m were 95% and 18 W m−2, respectively, while the corresponding values were 86% and 29 W m−2 at a height of 1.8 m for the autumn planting season. For the spring planting season, the EF and RMSE were 92% and 34 W m−2 at a height of 0.5 m, while the corresponding values were 81% and 56 W m−2 at a height of 1.8 m, respectively. This work demonstrated that when micrometeorological data within the canopy was applied alongside the data measured above the canopy, the SM led to better agreement with the lysimeter measurements.

ACS Style

Haofang Yan; Song Huang; Chuan Zhang; Miriam Coenders Gerrits; Guoqing Wang; Jianyun Zhang; Baoshan Zhao; Samuel Joe Acquah; Haimei Wu; Hanwen Fu. Parameterization and Application of Stanghellini Model for Estimating Greenhouse Cucumber Transpiration. Water 2020, 12, 517 .

AMA Style

Haofang Yan, Song Huang, Chuan Zhang, Miriam Coenders Gerrits, Guoqing Wang, Jianyun Zhang, Baoshan Zhao, Samuel Joe Acquah, Haimei Wu, Hanwen Fu. Parameterization and Application of Stanghellini Model for Estimating Greenhouse Cucumber Transpiration. Water. 2020; 12 (2):517.

Chicago/Turabian Style

Haofang Yan; Song Huang; Chuan Zhang; Miriam Coenders Gerrits; Guoqing Wang; Jianyun Zhang; Baoshan Zhao; Samuel Joe Acquah; Haimei Wu; Hanwen Fu. 2020. "Parameterization and Application of Stanghellini Model for Estimating Greenhouse Cucumber Transpiration." Water 12, no. 2: 517.

Preprint content
Published: 23 January 2020
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Forest evaporation exports a vast amount of water vapor from land ecosystems into the atmosphere. Meanwhile, evaporation during rain events is neglected or considered of minor importance in dense ecosystems. Air convection moves the water vapor upwards leading the formation of large invisible vapor plumes, while the identification of visible vapor plumes has not been studied yet. This work describes the formation process of vapor plumes in a tropical wet forest as evidence of evaporation processes happening during rain events. In the dry season of 2018 at La Selva Biological Station (LSBS) in Costa Rica it was possible to spot visible vapor plumes within the forest canopy. The combination of time-lapse videos at the canopy top with meteorological measurements along the canopy profile allowed to identify the conditions required for this process to happen. This phenomenon happened only during rain events, where evaporation measurements showed contributions of 1.8 mm d−1. Visible vapor plumes during day time occurred on the presence of precipitation (P), air convection identified by the temperature gradient (Δϴv / Δz) at 2 m height, and a lifting condensation level at 43 m height (Zlcl.43) smaller than 100 m.

ACS Style

César Dionisio Jiménez-Rodríguez; Miriam Coenders-Gerrits; Bart Schilperoort; Adriana González-Angarita; Hubert Savenije. Vapor plumes in a tropical wet forest: spotting the invisible evaporation. 2020, 2020, 1 -20.

AMA Style

César Dionisio Jiménez-Rodríguez, Miriam Coenders-Gerrits, Bart Schilperoort, Adriana González-Angarita, Hubert Savenije. Vapor plumes in a tropical wet forest: spotting the invisible evaporation. . 2020; 2020 ():1-20.

Chicago/Turabian Style

César Dionisio Jiménez-Rodríguez; Miriam Coenders-Gerrits; Bart Schilperoort; Adriana González-Angarita; Hubert Savenije. 2020. "Vapor plumes in a tropical wet forest: spotting the invisible evaporation." 2020, no. : 1-20.

Preprint content
Published: 16 January 2020
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ACS Style

Miriam Coenders-Gerrits. Review "Partitioning the forest water balance within a boreal catchment using sapflux, eddy covariance and process-based model". 2020, 1 .

AMA Style

Miriam Coenders-Gerrits. Review "Partitioning the forest water balance within a boreal catchment using sapflux, eddy covariance and process-based model". . 2020; ():1.

Chicago/Turabian Style

Miriam Coenders-Gerrits. 2020. "Review "Partitioning the forest water balance within a boreal catchment using sapflux, eddy covariance and process-based model"." , no. : 1.

Chapter
Published: 02 January 2020 in Precipitation Partitioning by Vegetation
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While evaporation is the largest water consumer of terrestrial water, its importance is often (limitedly) linked to increasing crop productivities. As a consequence, our knowledge of the evaporation process is highly biased by agricultural settings, and results in erroneous estimates of evaporation for other land surfaces and especially for forest systems. The reason why crop and forest systems differ has to do with the vegetation height and what is happening in the space between the plant top and surface. Forests are multi-layered systems, where under the tallest tree species, lower vegetation layers are present. These lower vegetation layers transpire, but at a different rate then the main vegetation, since the atmospheric conditions are different under the canopy. Additionally, the sub-vegetation layers, and also the forest floor, intercept water. Next to different atmospheric conditions per layer, the interception process is highly complex due to differences in interception capacity and a time delay caused by the cascade of water when water flows from the top canopy down to the forest floor. Lastly, forests also have the capacity to store heat and vapor in the air column, biomass, and soil. While this energy storage can be up to 110 W/m2 it is often neglected in evaporation models. To get a better understanding of what is happening inside a forest, for the purpose of evaporation modeling, we should make use of new sensing techniques that allow identifying the rainfall, energy, and evaporation partitioning. This will help to improve evaporation estimates for tall vegetation, like forest, and allow spatial up scaling.

ACS Style

Miriam Coenders-Gerrits; Bart Schilperoort; César Jiménez-Rodríguez. Evaporative Processes on Vegetation: An Inside Look. Precipitation Partitioning by Vegetation 2020, 35 -48.

AMA Style

Miriam Coenders-Gerrits, Bart Schilperoort, César Jiménez-Rodríguez. Evaporative Processes on Vegetation: An Inside Look. Precipitation Partitioning by Vegetation. 2020; ():35-48.

Chicago/Turabian Style

Miriam Coenders-Gerrits; Bart Schilperoort; César Jiménez-Rodríguez. 2020. "Evaporative Processes on Vegetation: An Inside Look." Precipitation Partitioning by Vegetation , no. : 35-48.