Research Article| June 01, 2001 Strong tectonic and weak climatic control of long-term chemical weathering rates Clifford S. Riebe; Clifford S. Riebe 1Department of Earth and Planetary Science, University of California, Berkeley, California 94720-4767, USA Search for other works by this author on: GSW Google Scholar James W. Kirchner; James W. Kirchner 1Department of Earth and Planetary Science, University of California, Berkeley, California 94720-4767, USA Search for other works by this author on: GSW Google Scholar Darryl E. Granger; Darryl E. Granger 2Department of Earth and Atmospheric Sciences, Purdue University, West Lafayette, Indiana 47907, USA Search for other works by this author on: GSW Google Scholar Robert C. Finkel Robert C. Finkel 3Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, California 94551, USA Search for other works by this author on: GSW Google Scholar Geology (2001) 29 (6): 511–514. https://doi.org/10.1130/0091-7613(2001)029<0511:STAWCC>2.0.CO;2 Article history received: 05 Oct 2000 rev-recd: 06 Feb 2001 accepted: 22 Feb 2001 first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Clifford S. Riebe, James W. Kirchner, Darryl E. Granger, Robert C. Finkel; Strong tectonic and weak climatic control of long-term chemical weathering rates. Geology 2001;; 29 (6): 511–514. doi: https://doi.org/10.1130/0091-7613(2001)029<0511:STAWCC>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract The relationships among climate, physical erosion, and chemical weathering have remained uncertain, because long-term chemical weathering rates have been difficult to measure. Here we show that long-term chemical weathering rates can be measured by combining physical erosion rates, inferred from cosmogenic nuclides, with dissolution losses, inferred from the rock-to-soil enrichment of insoluble elements. We used this method to measure chemical weathering rates across 22 mountainous granitic catchments that span a wide range of erosion rates and climates. Chemical weathering rates correlate strongly with physical erosion rates but only weakly with climate, implying that, by regulating erosion rates, tectonic uplift may significantly accelerate chemical weathering rates in granitic landscapes. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.
In this study, volumetric soil moisture was monitored monthly for 5.5 years (April 2016 to October 2021) at 20 cm intervals between the surface and 5 m depth at 89 sites across a small (0.43 km2) catchment on the Chinese Loess Plateau. The median soil moisture was computed for each month and depth for each monitoring site as a measure of the typical soil moisture conditions. Here is the dataset for median soil moisture which can support our main finding:monthly_median_volumetric_soil_moisture_pct: the median soil moisture for each month and depth for each monitoring site during the measurement period,monthly_average_p_q_pet: the average monthly precipitation, average monthly potential evapotranspiration during the soil moisture measurement period, and the monthly streamflow from June 2016 to May 2017,monthly_average_solar_radiation_Wm2: the average solar radiation for each month and for each site over the soil moisture measurement period,topographic_attributes: the slope aspect and the topographic wetness index for each site.
Abstract Trees in seasonal climates may use water originating from both winter and summer precipitation. However, the seasonal origins of water used by trees have not been systematically studied. We used stable isotopes of water to compare the seasonal origins of water found in three common tree species across 24 Swiss forest sites sampled in two different years. Water from winter precipitation was observed in trees at most sites, even at the peak of summer, although the relative representation of seasonal sources differed by species. However, the representation of winter precipitation in trees decreased with site mean annual precipitation in both years; additionally, it was generally lower in the cooler and wetter year. Together, these relationships show that precipitation amount influenced the seasonal origin of water taken up by trees across both time and space. These results suggest higher turnover of the plant‐available soil‐water pool in wetter sites and wetter years.
Abstract Branching stream networks are a ubiquitous feature of the Earth's surface, but the processes that shape them, and their dependence on the climate in which they grow, remain poorly understood. Research has mainly focused on climatic controls of channel incision rates, while the climatic influence on planform geometry has often been overlooked. Here we analyze nearly one million digitally mapped river junctions throughout the contiguous United States and show that branching angles vary systematically with climatic aridity. In arid landscapes, which are thought to be dominated by surface runoff erosion, junction angles average roughly 45° in the driest places. Branching angles are systematically wider in humid regions, averaging roughly 72°, which is the theoretically predicted angle for network growth in a diffusive field such as groundwater seepage. The correlation of mean junction angle with aridity is stronger than with topographic gradient, downstream concavity, or other geometric factors that have been proposed as controls of junction angles. Thus, it may be possible to identify channelization processes from stream network geometry in relict landscapes, such as those on Mars.
Abstract. Quantifying seasonal variations in precipitation δ2H and δ18O is important for many stable isotope applications, including inferring plant water sources and streamflow ages. Here we present global maps that concisely quantify the seasonality of stable isotope ratios in precipitation. We fit sine curves defined by amplitude, phase and offset parameters to quantify annual precipitation isotope cycles at 653 meteorological stations on all seven continents. At most of these stations, including in tropical and subtropical regions, sine curves can adequately represent the seasonal cycles in precipitation isotopes. Additionally, the amplitude, phase, and offset parameters of these sine curves correlate with site climatic and geographic characteristics. Multiple linear regression models based on these site characteristics can map global precipitation isotope amplitudes, phases, and offsets. We then adjusted the regression-based maps for residual spatial variations that were not captured by the regression models. We make these gridded global maps of precipitation δ2H and δ18O cycles publicly available. We also make tabulated site data and fitted sine curve parameters available to support the development of regionally calibrated models, which will generally be more accurate than our global model for regionally specific studies.
The aggregate length of flowing streams in a drainage network lengthens and shortens as landscapes become wetter and drier. However, direct measurements of stream network variability have been limited to a handful of small drainage basins. We estimated the variability of stream network length for 14,765 gauged basins across the contiguous United States using measured streamflow distributions and topography-based estimates of how sensitive each stream network is to changing landscape wetness (the network’s elasticity). We find that the median US stream network is five times longer during annual high-flow conditions than during annual low-flow conditions. Stream networks are more dynamic in some regions than in others, driven by regional differences in both hydroclimatology and the networks’ elasticity in response to hydroclimatic forcing.
The Technical Note: "Calculation scripts for ensemble hydrograph separation" by Kirchner and Knapp, presents an ensemble hydrograph separation tool, useful to estimates new water fractions and transit time distributions (TTDs).The authors developed userfriendly scripts that perform EHS calculations in two broadly used platforms (MATLAB and R).The authors used an impressive synthetic data set, that despite the limitations they clearly stated in the manuscript, mimics reasonably the real word behavior of isotope time series.
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