The hydrology of the humid tropics

Wohl, Ellen; Barros, Ana P.; Brunsell, Nathaniel A.; Chappell, Nick A.; Coe, Michael T.; Giambelluca, Thomas W.; Goldsmith, Steven T.; Harmon, Russell S.; Hendrickx, Jan M. H.; Juvik, James O.; McDonnell, Jeffrey J.; Ogden, Fred L.

doi:10.1038/nclimate1556

Cited by 310 publications

(259 citation statements)

References 87 publications

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“…Combining this information with major terrace configurations (paired, unpaired, disconnected) and TPI identified that a combination of erosion and resistance factors are responsible for driving terrace preservation. This study provides important insights into terrace preservation in a humid tropical environment, filling a significant research gap in a region that is likely to undergo significant change in future climate and land use (Wohl et al, 2012). This study provides a framework for future research linking the timing of fluvial response to palaeoclimate change in the Wet Tropics.…”

Section: Resultsmentioning

confidence: 99%

Alluvial terrace preservation in the Wet Tropics, northeast Queensland, Australia

et al. 2015

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Alluvial terraces provide a record of aggradation and incision and are studied to understand river response to changes in climate, tectonic activity, sea level, and factors internal to the river system. Terraces form in all climatic regions and in a range of geomorphic settings; however, relatively few studies have been undertaken in tectonically stable settings in the tropics. The preservation of alluvial terraces in a valley is driven by lateral channel adjustments, vertical incision, aggradation, and channel stability, processes that can be further understood through examining catchment force-resistance frameworks. This study maps and classifies terraces using soil type, surface elevation, sedimentology, and optically stimulated luminescence dating across five tropical catchments in northeast Queensland, Australia. This allowed for the identification of two terraces across the study catchments (T1, T2).The T1 terrace was abandoned ~13.9 ka with its subsequent removal occurring until ~7.4 ka. Abandonment of the T2 terrace occurred ~4.9 ka with removal occurring until ~1.2 ka. Differences in the spatial preservation of these terraces were described using an index of terrace preservation (TPI). Assessments of terrace remnant configuration highlighted three main types of terraces: paired, unpaired, and disconnected, indicating the importance of different processes driving preservation.Regional-scale variability in TPI was not strongly correlated with catchment-scale surrogate variables for drivers of terrace erosion and resistance. However, catchmentspecific relationships between TPI and erosion-resistance variables were evident and are used here to explain the dominant processes driving preservation in these tropical settings. This study provides an important insight into terrace preservation in the tectonically stable, humid tropics and provides a framework for future research linking the timing of fluvial response to palaeoclimate change. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT IntroductionAlluvial terraces are topographic landforms that result from floodplain abandonment when a river incises, therefore providing records of river aggradation and incision (Leopold et al., 1964). Terraces have formed in all global regions and are commonly studied to understand how rivers have responded to the combined effects of changes in external controls including climate, tectonics, and sea level (Merritts et al., 1994;Macklin et al., 2002;Bridgland and Westaway, 2008) and in internal controls, such as catchment morphology (Coulthard et al., 2005) and reach-specific conditions (Houben, 2003).Terraces are generally identified in the landscape using a range of techniques including soil properties (see reviews in Birkeland, 1990;Huggett, 1998), topographic data (Pazzaglia and Gardner, 1993;Jones et al., 2007), aerial and satellite imagery (Litchfield and Berryman, 2005), with correlations further aided by sedimentology and dating (Stokes et al., 2012). The use of soil characteristics to classify terrace...

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Section: Resultsmentioning

confidence: 99%

Alluvial terrace preservation in the Wet Tropics, northeast Queensland, Australia

et al. 2015

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“…In 2014, The Nature Conservancy announced a US$ 27M investment in a Latin American Water Funds Partnership with the stated objective of managing *3 million hectares of watershed lands (The Nature Conservancy 2014). Despite these investments, empirical data on water flows within and across the broad suite of tropical land-cover types targeted for investments are surprisingly limited (Wohl et al 2012;Ponette-González et al 2014). As a result, land cover proxies for water service provision are often based on observations from temperate ecosystems or, as noted by Calder (2004), on 'conventional wisdom' that may prove inappropriate for tropical systems.…”

Section: Introductionmentioning

confidence: 99%

Managing water services in tropical regions: From land cover proxies to hydrologic fluxes

Ponette‐González

Brauman

Marín-Spiotta

et al. 2014

Ambio

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Watershed investment programs frequently use land cover as a proxy for water-based ecosystem services, an approach based on assumed relationships between land cover and hydrologic outcomes. Water flows are rarely quantified, and unanticipated results are common, suggesting land cover alone is not a reliable proxy for water services. We argue that managing key hydrologic fluxes at the site of intervention is more effective than promoting particular land-cover types. Moving beyond land cover proxies to a focus on hydrologic fluxes requires that programs (1) identify the specific water service of interest and associated hydrologic flux; (2) account for structural and ecological characteristics of the relevant land cover; and, (3) determine key mediators of the target hydrologic flux. Using examples from the tropics, we illustrate how this conceptual framework can clarify interventions with a higher probability of delivering desired water services than with land cover as a proxy.

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“…The humid tropics concentrate a large amount of net radiation and water vapor, and consequently, intense heat and humidity fluxes dominate the interactions between the soil and the lower atmosphere [1]. The excess of net radiation is balanced through latent heat and sensible heat fluxes [2][3][4].…”

Section: Introductionmentioning

confidence: 99%

<strong>New insights on land surface-atmosphere feedbacks over tropical South America at interannual timescales</strong>

Bedoya-Soto

Poveda

2017

Proceedings of First International Electronic Conference on the Hydrological Cycle

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Abstract:Using monthly data for the period 1979-2010, we study the dynamics and strength of land surface-atmosphere feedbacks (LAFs) among variables involved in the heat and moisture fluxes, at interannual timescales in Tropical South America (TropSA). The variables include precipitation, surface air temperature, specific humidity at 925 hPa, evaporation, and estimates of volumetric soil water content. We use a Maximum Covariance Analysis (MCA) to reduce the dimensionality and to rank the relative contributions to LAFs and group the time series into Maximum Covariance States (MCS) with common mechanisms among variables. We estimate linear (Pearson correlations) and non-linear association (information transfer or causality) metrics among pairs of variables to configure the structure of linkages. The main MCS associated with LAFs over TropSA are strongly influenced by ENSO, and the meridional and equatorial SSTs modes over the Atlantic and Indian Oceans. ENSO favors a unimodal behavior, with center of action in the Amazon River basin, while the SSTs mode over the Tropical North Atlantic (TNA) results in a dipole between northern and southern TropSA. Our results show that soil moisture plays a leading role in regulating heat and water anomalies, and provides the memory of the LAFs and their subsequent influence. Thus, volumetric soil water becomes a fundamental variable leading up to 9 month-lags. ENSO enhances the interannual connectivity and memory inside LAF mechanisms with respect to other modes. Within the identified multivariate structure, evaporation and soil moisture enhance the interannual connectivity of the whole set of variables since both variables exhibit more frequent two-way feedbacks with the remaining variables.

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The hydrology of the humid tropics

Cited by 310 publications

References 87 publications

Alluvial terrace preservation in the Wet Tropics, northeast Queensland, Australia

Alluvial terrace preservation in the Wet Tropics, northeast Queensland, Australia

Managing water services in tropical regions: From land cover proxies to hydrologic fluxes

<strong>New insights on land surface-atmosphere feedbacks over tropical South America at interannual timescales</strong>

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