Designing a suite of measurements to understand the critical zone

Abstract. Many scientists have begun to refer to the earth surface environment from the upper canopy to the depths of bedrock as the critical zone (CZ). Identification of the CZ as an integral object worthy of study implicitly posits that the study of the whole earth surface will provide benefits that do not arise when studying the individual parts. To study the CZ, however, requires prioritizing among the measurements that can be made – and we do not generally agree on the priorities. Currently, the Susquehanna Shale Hills Critical Zone Observatory (SSHCZO) is expanding from a small original focus area (0.08 km2, Shale Hills catchment), to a larger watershed (164 km2, Shavers Creek watershed) and is grappling with the prioritization. This effort is an expansion from a monolithologic first-order forested catchment to a watershed that encompasses several lithologies (shale, sandstone, limestone) and land use types (forest, agriculture). The goal of the project remains the same: to understand water, energy, gas, solute, and sediment (WEGSS) fluxes that are occurring today in the context of the record of those fluxes over geologic time as recorded in soil profiles, the sedimentary record, and landscape morphology. Given the small size of the Shale Hills catchment, the original design incorporated measurement of as many parameters as possible at high temporal and spatial density. In the larger Shavers Creek watershed, however, we must focus the measurements. We describe a strategy of data collection and modeling based on a geomorphological and land use framework that builds on the hillslope as the basic unit. Interpolation and extrapolation beyond specific sites relies on geophysical surveying, remote sensing, geomorphic analysis, the study of natural integrators such as streams, groundwaters or air, and application of a suite of CZ models. We hypothesize that measurements of a few important variables at strategic locations within a geomorphological framework will allow development of predictive models of CZ behavior. In turn, the measurements and models will reveal how the larger watershed will respond to perturbations both now and into the future.

[1]  James C. Bell,et al.  A periglacial stratified slope deposit in the valley and ridge province of central Pennsylvania, USA: Sedimentology, stratigraphy, and geomorphic evolution , 1991 .

[2]  M. Lebedeva,et al.  Learning to Read the Chemistry of Regolith to Understand the Critical Zone , 2011 .

[3]  S. Willett,et al.  Dynamic Reorganization of River Basins , 2014, Science.

[4]  Jin Chen,et al.  Subsurface lateral preferential flow network revealed by time‐lapse ground‐penetrating radar in a hillslope , 2014 .

[5]  K. Whipple,et al.  Rapid incision of the Colorado River in Glen Canyon – insights from channel profiles, local incision rates, and modeling of lithologic controls , 2009 .

[6]  Christopher J. Duffy,et al.  Parameter estimation of a physically based land surface hydrologic model using the ensemble Kalman filter: A synthetic experiment , 2014 .

[7]  S. Running,et al.  MODIS Leaf Area Index (LAI) And Fraction Of Photosynthetically Active Radiation Absorbed By Vegetation (FPAR) Product , 1999 .

[8]  E. Ciolkosz,et al.  COLLUVIAL SOIL PARENT MATERIAL RELATIONSHIPS IN THE RIDGE AND VALLEY PHYSIOGRAPHIC PROVINCE OF PENNSYLVANIA1 , 1988 .

[9]  Henry Lin,et al.  Soil moisture patterns in a forested catchment: A hydropedological perspective , 2006 .

[10]  Christopher J. Duffy,et al.  Designing a Suite of Models to Explore Critical Zone Function , 2014, Procedia Earth and Planetary Science.

[11]  Sandy P. Harrison,et al.  Climate change and Arctic ecosystems: 2. Modeling, paleodata‐model comparisons, and future projections , 2003 .

[12]  C. Duffy,et al.  Spatiotemporal Patterns of Water Stable Isotope Compositions at the Shale Hills Critical Zone Observatory: Linkages to Subsurface Hydrologic Processes , 2013 .

[13]  S. Brantley,et al.  Earthcasting the future Critical Zone , 2013 .

[14]  E. Kirby,et al.  Regolith production and transport in the Susquehanna Shale Hills Critical Zone Observatory, Part 1: Insights from U‐series isotopes , 2013 .

[15]  J. Kaye,et al.  Topographic controls on the depth distribution of soil CO2 in a small temperate watershed , 2015 .

[16]  William E. Dietrich,et al.  Constitutive mass balance relations between chemical composition, volume, density, porosity, and strain in metasomatic hydrochemical systems: Results on weathering and pedogenesis , 1987 .

[17]  C. Duffy,et al.  The CO2 consumption potential during gray shale weathering: Insights from the evolution of carbon isotopes in the Susquehanna Shale Hills critical zone observatory , 2014 .

[18]  Christopher J. Duffy,et al.  Parameter estimation of a physically-based land surface hydrologic model using an ensemble Kalman filter: A multivariate real-data experiment , 2015 .

[19]  Jeff Dozier,et al.  Evaluation of distributed hydrologic impacts of temperature-index and energy-based snow models , 2013 .

[20]  E. Kirby,et al.  Tectonic and lithologic controls on bedrock channel profiles and processes in coastal California , 2004 .

[21]  R. Ravella,et al.  Mineral weathering and elemental transport during hillslope evolution at the Susquehanna/Shale Hills Critical Zone Observatory , 2010 .

[22]  O. Chadwick,et al.  The chemistry of pedogenic thresholds , 2001 .

[23]  F. P. Kapinos,et al.  Hydrologic unit maps , 1987 .

[24]  Martin Novak,et al.  Soil processes and functions across an international network of Critical Zone Observatories: Introduction to experimental methods and initial results , 2012 .

[25]  Budiman Minasny,et al.  Quantitative models for pedogenesis — A review , 2008 .

[26]  Thomas C. Harmon,et al.  Watershed model calibration to the base flow recession curve with and without evapotranspiration effects , 2016 .

[27]  Heather McGraw,et al.  Human Alteration of the Global Nitrogen Cycle , 2004 .

[28]  Christopher J. Duffy,et al.  Evaluation of the Parameter Sensitivities of a Coupled Land Surface Hydrologic Model at a Critical Zone Observatory , 2014 .

[29]  R. B. Jackson,et al.  Measuring Water Availability and Uptake in Ecosystem Studies , 2000 .

[30]  C. Hunsaker,et al.  Hydrogeologic influence on changes in snowmelt runoff with climate warming: Numerical experiments on a mid-elevation catchment in the Sierra Nevada, USA , 2015 .

[31]  M. Lebedeva,et al.  Exploring geochemical controls on weathering and erosion of convex hillslopes: beyond the empirical regolith production function , 2013 .

[32]  Danny Marks,et al.  Anomalous trend in soil evaporation in a semi-arid, snow-dominated watershed , 2012 .

[33]  C. B. Graham,et al.  Controls and Frequency of Preferential Flow Occurrence: A 175‐Event Analysis , 2011 .

[34]  A. Edwards,et al.  Weathering of sandstone clasts in a forest soil in Tuscany (Italy) , 2003 .

[35]  D. Tarboton.  A new method for the determination of flow directions and upslope areas in grid digital elevation models , 1997 .

[36]  S. Running,et al.  Global products of vegetation leaf area and fraction absorbed PAR from year one of MODIS data , 2002 .

[37]  J. Bochen,et al.  Sandstone degradation: an experimental study of accelerated weathering , 2012, Environmental Earth Sciences.

[38]  J. Kirchner,et al.  Concentration–discharge relationships reflect chemostatic characteristics of US catchments , 2009 .

[39]  Suming Jin,et al.  Completion of the 2011 National Land Cover Database for the Conterminous United States – Representing a Decade of Land Cover Change Information , 2015 .

[40]  E. Crompton,et al.  Soil Formation , 1962 .

[41]  C. Duffy,et al.  Oxidative dissolution under the channel leads geomorphological evolution at the Shale Hills catchment , 2016, American Journal of Science.

[42]  Henry Lin,et al.  Repeated Electromagnetic Induction Surveys for Determining Subsurface Hydrologic Dynamics in an Agricultural Landscape , 2010 .

[43]  Lixin Jin,et al.  Opening the “Black Box”: Water Chemistry Reveals Hydrological Controls on Weathering in the Susquehanna Shale Hills Critical Zone Observatory , 2011 .

[44]  W. J. Shuttleworth,et al.  COSMOS: the COsmic-ray Soil Moisture Observing System , 2012 .

[45]  J. Doolittle,et al.  Soil layering and preferential flow impacts on seasonal changes of GPR signals in two contrasting soils , 2014 .

[46]  D. Rizzo,et al.  Low rates of bedrock outcrop erosion in the central Appalachian Mountains inferred from in situ 10Be , 2013 .

[47]  P. Crutzen.  Geology of mankind , 2002, Nature.

[48]  S. P. Anderson,et al.  The Role of Critical Zone Observatories in Critical Zone Science , 2015 .

[49]  P. Warnant,et al.  CARAIB - A global model of terrestrial biological productivity , 1994 .

[50]  Christopher J. Duffy,et al.  Modelling long-term water yield effects of forest management in a Norway spruce forest , 2015 .

[51]  E. Kirby,et al.  Regolith production and transport at the Susquehanna Shale Hills Critical Zone Observatory, Part 2: Insights from meteoric 10Be , 2013 .

[52]  Henry Lin,et al.  Spatial Distribution of Tree Species Governs the Spatio-Temporal Interaction of Leaf Area Index and Soil Moisture across a Forested Landscape , 2013, PloS one.

[53]  Anne Probst,et al.  Modelling weathering processes at the catchment scale: The WITCH numerical model , 2006 .

[54]  E. Kirby,et al.  Neogene rejuvenation of central Appalachian topography: Evidence for differential rock uplift from stream profiles and erosion rates , 2013 .

[55]  B. J. Carter,et al.  Genesis of soils and landscapes in the Ridge and Valley province of central Pennsylvania , 1990 .

[56]  T. S. Adams,et al.  Above- and belowground controls on water use by trees of different wood types in an eastern US deciduous forest. , 2013, Tree physiology.

[57]  B. Wilkinson,et al.  THE IMPACT OF HUMANS ON CONTINENTAL EROSION AND SEDIMENTATION (Invited) , 2007 .

[58]  Christopher J. Duffy,et al.  Development of a Coupled Land Surface Hydrologic Model and Evaluation at a Critical Zone Observatory , 2013 .

[59]  W. Dietrich,et al.  Geomorphic transport laws for predicting landscape form and dynamics , 2013 .

[60]  T. Paradise,et al.  Sandstone weathering: a century of research and innovation , 2005 .

[61]  E. Kirby,et al.  Aspect-dependent variations in regolith creep revealed by meteoric 10Be , 2014 .

[62]  Henry Lin,et al.  Repeated electromagnetic induction surveys for improved soil mapping in an agricultural landscape. , 2010 .

[63]  Rafael Rosolem,et al.  A universal calibration function for determination of soil moisture with cosmic-ray neutrons , 2012 .

[64]  K. Beven.  Rainfall-Runoff Modelling: The Primer , 2012 .

[65]  K. Whipple,et al.  9.28 Bedrock Rivers , 2013 .

[66]  Christopher J. Duffy,et al.  Simulating high‐resolution soil moisture patterns in the Shale Hills watershed using a land surface hydrologic model , 2015 .

[67]  Lin Ma,et al.  How mineralogy and slope aspect affect REE release and fractionation during shale weathering in the Susquehanna/Shale Hills Critical Zone Observatory , 2011 .

[68]  Douglas A. Miller,et al.  An Ontology Driven Relational Geochemical Database for the Earth's Critical Zone: CZchemDB , 2014 .

[69]  Frederick L. Paillet,et al.  Hydrogeology of the Potsdam Sandstone in Northern New York , 2010 .

[70]  S. P. Anderson,et al.  Linkages Between Weathering and Erosion in a Small, Steep Catchment , 2002 .

[71]  Susan L. Brantley,et al.  A mathematical model for steady‐state regolith production at constant erosion rate , 2010 .

[72]  C. Zweck,et al.  Snow shielding factors for cosmogenic nuclide dating inferred from Monte Carlo neutron transport simulations , 2013 .

[73]  Susan L. Brantley,et al.  A reactive diffusion model describing transformation of bedrock to saprolite , 2007 .

[74]  Christopher P. McKay,et al.  A threshold in soil formation at Earth's arid-hyperarid transition , 2006 .

[75]  H. Mooney,et al.  Human Domination of Earth’s Ecosystems , 1997, Renewable Energy.

[76]  Allan J. Delaney,et al.  Dielectric properties of soils at UHF and microwave frequencies , 1974 .

[77]  D. Dewalle,et al.  Influence of bedrock geology and tree species composition on stream nitrate concentrations in mid-appalachian forested watersheds , 2005 .

[78]  C. Duffy,et al.  A semidiscrete finite volume formulation for multiprocess watershed simulation , 2007 .

[79]  A. P. Annan,et al.  Electromagnetic determination of soil water content: Measurements in coaxial transmission lines , 1980 .

[80]  R. Amundson.  5.01 – Soil Formation , 2003 .

[81]  B. J. Carter,et al.  Slope gradient and aspect effects on soils developed from sandstone in Pennsylvania , 1991 .