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Eric F Wood - One of the best experts on this subject based on the ideXlab platform.
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Improving Understanding of the Global Hydrologic Cycle
Climate Science for Serving Society, 2013Co-Authors: Peter H. Gleick, Heather Cooley, James S. Famiglietti, Dennis P. Lettenmaier, Charles J. Vörösmarty, Eric F WoodAbstract:Understanding the complexity of the Hydrological Cycle is central to understanding a wide range of other planetary geological, atmospheric, chemical, and physical processes. Water is also central to other core economic, social, and political issues such as poverty, health, hunger, environmental sustainability, conflict, and economic prosperity. As society seeks to meet demands for goods and services for a growing population, we must improve our understanding of the fundamental science of the Hydrological Cycle, its links with related global processes, and the role it plays in ecological and societal well-being. At the same time, human influences on the character and dynamics of the water Cycle are growing rapidly. Central to solving these challenges is the need to improve our systems for managing, sharing, and analyzing all kinds of water data, and our ability to model and forecast aspects of both the Hydrological Cycle and the systems we put in place to manage human demands for water. We need to improve our understanding of each of the components of the Hydrological water balance at all scales, and to understand the spatial and temporal variability in the components of the water Cycle. This chapter provides a short summary of current WCRP efforts and addresses four primary research challenges: 1. The collection of more comprehensive data and information on all aspects of the Hydrologic Cycle and human uses of water, at enhanced spatial and temporal resolution and increased precision; 2. Improved management and distribution of these data; 3. Improved representation of the anthropogenic manipulations of the water Cycle in the coupled land-atmosphere-ocean models used to forecast climate variations and change at both seasonal to interannual, and decade to century, time scales; and 4. Expanded research at the intersection of Hydrological sciences and the technical, social, economic, and political aspects of freshwater management and use.
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global trends and variability in soil moisture and drought characteristics 1950 2000 from observation driven simulations of the terrestrial Hydrologic Cycle
Journal of Climate, 2008Co-Authors: Justin Sheffield, Eric F WoodAbstract:Abstract Global and regional trends in drought for 1950–2000 are analyzed using a soil moisture–based drought index over global terrestrial areas, excluding Greenland and Antarctica. The soil moisture fields are derived from a simulation of the terrestrial Hydrologic Cycle driven by a hybrid reanalysis–observation forcing dataset. Drought is described in terms of various statistics that summarize drought duration, intensity, and severity. There is an overall small wetting trend in global soil moisture, forced by increasing precipitation, which is weighted by positive soil moisture trends over the Western Hemisphere and especially in North America. Regional variation is nevertheless apparent, and significant drying over West Africa, as driven by decreasing Sahel precipitation, stands out. Elsewhere, Europe appears to have not experienced significant changes in soil moisture, a trait shared by Southeast and southern Asia. Trends in drought duration, intensity, and severity are predominantly decreasing, but ...
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development of a 50 year high resolution global dataset of meteorological forcings for land surface modeling
Journal of Climate, 2006Co-Authors: Justin Sheffield, G Goteti, Eric F WoodAbstract:Abstract Understanding the variability of the terrestrial Hydrologic Cycle is central to determining the potential for extreme events and susceptibility to future change. In the absence of long-term, large-scale observations of the components of the Hydrologic Cycle, modeling can provide consistent fields of land surface fluxes and states. This paper describes the creation of a global, 50-yr, 3-hourly, 1.0° dataset of meteorological forcings that can be used to drive models of land surface hydrology. The dataset is constructed by combining a suite of global observation-based datasets with the National Centers for Environmental Prediction–National Center for Atmospheric Research (NCEP–NCAR) reanalysis. Known biases in the reanalysis precipitation and near-surface meteorology have been shown to exert an erroneous effect on modeled land surface water and energy budgets and are thus corrected using observation-based datasets of precipitation, air temperature, and radiation. Corrections are also made to the ra...
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teleconnection between the arctic oscillation and hudson bay river discharge
Geophysical Research Letters, 2004Co-Authors: Stephen J Dery, Eric F WoodAbstract:[1] Rising surface air temperatures in response to anthropogenic forcing are intensifying the global Hydrologic Cycle. Some of the more dramatic signs of climate change are increasing precipitation, evaporation, and freshwater discharge in continental river basins draining to high-latitude oceans. At regional scales, however, an acceleration of the Hydrologic Cycle is not always detected. In contrast to its major Eurasian counterparts, the North American Hudson Bay Basin experienced a 15% decline in river runoff between 1964 and 1994. It is shown that the Arctic Oscillation explains with statistical significance up to 90% of the recent variability in Hudson Bay river discharge. This study reveals the important role of large-scale atmospheric phenomena such as the Arctic Oscillation in regulating the terrestrial Hydrologic budget. The ability of weather and climate models to represent these interannual to decadal scale phenomena governs their predictions of the surface water budget's future state in a changing climate.
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teleconnection between the arctic oscillation and hudson bay river discharge
Geophysical Research Letters, 2004Co-Authors: Stephen J Dery, Eric F WoodAbstract:[1] Rising surface air temperatures in response to anthropogenic forcing are intensifying the global Hydrologic Cycle. Some of the more dramatic signs of climate change are increasing precipitation, evaporation, and freshwater discharge in continental river basins draining to high-latitude oceans. At regional scales, however, an acceleration of the Hydrologic Cycle is not always detected. In contrast to its major Eurasian counterparts, the North American Hudson Bay Basin experienced a 15% decline in river runoff between 1964 and 1994. It is shown that the Arctic Oscillation explains with statistical significance up to 90% of the recent variability in Hudson Bay river discharge. This study reveals the important role of large-scale atmospheric phenomena such as the Arctic Oscillation in regulating the terrestrial Hydrologic budget. The ability of weather and climate models to represent these interannual to decadal scale phenomena governs their predictions of the surface water budget's future state in a changing climate.
Stephen J Dery - One of the best experts on this subject based on the ideXlab platform.
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teleconnection between the arctic oscillation and hudson bay river discharge
Geophysical Research Letters, 2004Co-Authors: Stephen J Dery, Eric F WoodAbstract:[1] Rising surface air temperatures in response to anthropogenic forcing are intensifying the global Hydrologic Cycle. Some of the more dramatic signs of climate change are increasing precipitation, evaporation, and freshwater discharge in continental river basins draining to high-latitude oceans. At regional scales, however, an acceleration of the Hydrologic Cycle is not always detected. In contrast to its major Eurasian counterparts, the North American Hudson Bay Basin experienced a 15% decline in river runoff between 1964 and 1994. It is shown that the Arctic Oscillation explains with statistical significance up to 90% of the recent variability in Hudson Bay river discharge. This study reveals the important role of large-scale atmospheric phenomena such as the Arctic Oscillation in regulating the terrestrial Hydrologic budget. The ability of weather and climate models to represent these interannual to decadal scale phenomena governs their predictions of the surface water budget's future state in a changing climate.
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teleconnection between the arctic oscillation and hudson bay river discharge
Geophysical Research Letters, 2004Co-Authors: Stephen J Dery, Eric F WoodAbstract:[1] Rising surface air temperatures in response to anthropogenic forcing are intensifying the global Hydrologic Cycle. Some of the more dramatic signs of climate change are increasing precipitation, evaporation, and freshwater discharge in continental river basins draining to high-latitude oceans. At regional scales, however, an acceleration of the Hydrologic Cycle is not always detected. In contrast to its major Eurasian counterparts, the North American Hudson Bay Basin experienced a 15% decline in river runoff between 1964 and 1994. It is shown that the Arctic Oscillation explains with statistical significance up to 90% of the recent variability in Hudson Bay river discharge. This study reveals the important role of large-scale atmospheric phenomena such as the Arctic Oscillation in regulating the terrestrial Hydrologic budget. The ability of weather and climate models to represent these interannual to decadal scale phenomena governs their predictions of the surface water budget's future state in a changing climate.
Greg A Ludvigson - One of the best experts on this subject based on the ideXlab platform.
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quantification of a greenhouse Hydrologic Cycle from equatorial to polar latitudes the mid cretaceous water bearer revisited
Palaeogeography Palaeoclimatology Palaeoecology, 2011Co-Authors: Marina B Suarez, Luis A Gonzalez, Greg A LudvigsonAbstract:Abstract This study aims to investigate the global Hydrologic Cycle during the mid-Cretaceous greenhouse by utilizing the oxygen isotopic composition of pedogenic carbonates (calcite and siderite) as proxies for the oxygen isotopic composition of precipitation. The data set builds on the Aptian–Albian sphaerosiderite δ18O data set presented by Ufnar et al. (2002) by incorporating additional low latitude data including pedogenic and early meteoric diagenetic calcite δ18O. Ufnar et al. (2002) used the proxy data derived from the North American Cretaceous Western Interior Basin (KWIB) in a mass balance model to estimate precipitation–evaporation fluxes. We have revised this mass balance model to handle sphaerosiderite and calcite proxies, and to account for longitudinal travel by tropical air masses. We use empirical and general circulation model (GCM) temperature gradients for the mid-Cretaceous, and the empirically derived δ18O composition of groundwater as constraints in our mass balance model. Precipitation flux, evaporation flux, relative humidity, seawater composition, and continental feedback are adjusted to generate model calculated groundwater δ18O compositions (proxy for precipitation δ18O) that match the empirically-derived groundwater δ18O compositions to within ± 0.5‰. The model is calibrated against modern precipitation data sets. Four different Cretaceous temperature estimates were used: the leaf physiognomy estimates of Wolfe and Upchurch (1987) and Spicer and Corfield (1992), the coolest and warmest Cretaceous estimates compiled by Barron (1983) and model outputs from the GENESIS-MOM GCM by Zhou et al. (2008). Precipitation and evaporation fluxes for all the Cretaceous temperature gradients utilized in the model are greater than modern precipitation and evaporation fluxes. Balancing the model also requires relative humidity in the subtropical dry belt to be significantly reduced. As expected calculated precipitation rates are all greater than modern precipitation rates. Calculated global average precipitation rates range from 371 mm/year to 1196 mm/year greater than modern precipitation rates. Model results support the hypothesis that increased rainout produces δ18O-depleted precipitation. Sensitivity testing of the model indicates that the amount of water vapor in the air mass, and its origin and pathway, significantly affect the oxygen isotopic composition of precipitation. Precipitation δ18O is also sensitive to seawater δ18O and enriched tropical seawater was necessary to simulate proxy data (consistent with fossil and geologic evidence for a warmer and evaporatively enriched Tethys). Improved constraints in variables such as seawater δ18O can help improve boundary conditions for mid-Cretaceous climate simulations.
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the mid cretaceous water bearer isotope mass balance quantification of the albian Hydrologic Cycle
Palaeogeography Palaeoclimatology Palaeoecology, 2002Co-Authors: David F Ufnar, Luis A Gonzalez, Greg A Ludvigson, Robert L Brenner, Brian J WitzkeAbstract:A latitudinal gradient in meteoric N 18 O compositions compiled from paleosol sphaerosiderites throughout the Cretaceous Western Interior Basin (KWIB) (34^75‡N paleolatitude) exhibits a steeper, more depleted trend than modern (predicted) values (3.0x [34‡N latitude] to 9.7x [75‡N] lighter). Furthermore, the sphaerosiderite meteoric N 18 O latitudinal gradient is significantly steeper and more depleted (5.8x [34‡N] to 13.8x [75‡N] lighter) than a predicted gradient for the warm mid-Cretaceous using modern empirical temperature^N 18 O precipitation relationships. We have suggested that the steeper and more depleted (relative to the modern theoretical gradient) meteoric sphaerosiderite N 18 O latitudinal gradient resulted from increased air mass rainout effects in coastal areas of the KWIB during the mid-Cretaceous. The sphaerosiderite isotopic data have been used to constrain a mass balance model of the Hydrologic Cycle in the northern hemisphere and to quantify precipitation rates of the equable ‘greenhouse’ Albian Stage in the KWIB. The mass balance model tracks the evolving isotopic composition of an air mass and its precipitation, and is driven by latitudinal temperature gradients. Our simulations indicate that significant increases in Albian precipitation (34^52%) and evaporation fluxes (76^96%) are required to reproduce the difference between modern and Albian meteoric siderite N 18 O latitudinal gradients. Calculations of precipitation rates from model outputs suggest mid^high latitude precipitation rates greatly exceeded modern rates (156^220% greater in mid latitudes [2600^3300 mm/yr], 99% greater at high latitudes [550 mm/yr]). The calculated precipitation rates are significantly different from the precipitation rates predicted by some recent general circulation models (GCMs) for the warm Cretaceous, particularly in the mid to high latitudes. Our mass balance model by no means replaces GCMs. However, it is a simple and effective means of obtaining quantitative data regarding the mid-Cretaceous Hydrologic Cycle in the KWIB. Our goal is to encourage the incorporation of isotopic tracers into GCM simulations of the midCretaceous, and to show how our empirical data and mass balance model estimates help constrain the boundary conditions.
Luis A Gonzalez - One of the best experts on this subject based on the ideXlab platform.
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quantification of a greenhouse Hydrologic Cycle from equatorial to polar latitudes the mid cretaceous water bearer revisited
Palaeogeography Palaeoclimatology Palaeoecology, 2011Co-Authors: Marina B Suarez, Luis A Gonzalez, Greg A LudvigsonAbstract:Abstract This study aims to investigate the global Hydrologic Cycle during the mid-Cretaceous greenhouse by utilizing the oxygen isotopic composition of pedogenic carbonates (calcite and siderite) as proxies for the oxygen isotopic composition of precipitation. The data set builds on the Aptian–Albian sphaerosiderite δ18O data set presented by Ufnar et al. (2002) by incorporating additional low latitude data including pedogenic and early meteoric diagenetic calcite δ18O. Ufnar et al. (2002) used the proxy data derived from the North American Cretaceous Western Interior Basin (KWIB) in a mass balance model to estimate precipitation–evaporation fluxes. We have revised this mass balance model to handle sphaerosiderite and calcite proxies, and to account for longitudinal travel by tropical air masses. We use empirical and general circulation model (GCM) temperature gradients for the mid-Cretaceous, and the empirically derived δ18O composition of groundwater as constraints in our mass balance model. Precipitation flux, evaporation flux, relative humidity, seawater composition, and continental feedback are adjusted to generate model calculated groundwater δ18O compositions (proxy for precipitation δ18O) that match the empirically-derived groundwater δ18O compositions to within ± 0.5‰. The model is calibrated against modern precipitation data sets. Four different Cretaceous temperature estimates were used: the leaf physiognomy estimates of Wolfe and Upchurch (1987) and Spicer and Corfield (1992), the coolest and warmest Cretaceous estimates compiled by Barron (1983) and model outputs from the GENESIS-MOM GCM by Zhou et al. (2008). Precipitation and evaporation fluxes for all the Cretaceous temperature gradients utilized in the model are greater than modern precipitation and evaporation fluxes. Balancing the model also requires relative humidity in the subtropical dry belt to be significantly reduced. As expected calculated precipitation rates are all greater than modern precipitation rates. Calculated global average precipitation rates range from 371 mm/year to 1196 mm/year greater than modern precipitation rates. Model results support the hypothesis that increased rainout produces δ18O-depleted precipitation. Sensitivity testing of the model indicates that the amount of water vapor in the air mass, and its origin and pathway, significantly affect the oxygen isotopic composition of precipitation. Precipitation δ18O is also sensitive to seawater δ18O and enriched tropical seawater was necessary to simulate proxy data (consistent with fossil and geologic evidence for a warmer and evaporatively enriched Tethys). Improved constraints in variables such as seawater δ18O can help improve boundary conditions for mid-Cretaceous climate simulations.
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the mid cretaceous water bearer isotope mass balance quantification of the albian Hydrologic Cycle
Palaeogeography Palaeoclimatology Palaeoecology, 2002Co-Authors: David F Ufnar, Luis A Gonzalez, Greg A Ludvigson, Robert L Brenner, Brian J WitzkeAbstract:A latitudinal gradient in meteoric N 18 O compositions compiled from paleosol sphaerosiderites throughout the Cretaceous Western Interior Basin (KWIB) (34^75‡N paleolatitude) exhibits a steeper, more depleted trend than modern (predicted) values (3.0x [34‡N latitude] to 9.7x [75‡N] lighter). Furthermore, the sphaerosiderite meteoric N 18 O latitudinal gradient is significantly steeper and more depleted (5.8x [34‡N] to 13.8x [75‡N] lighter) than a predicted gradient for the warm mid-Cretaceous using modern empirical temperature^N 18 O precipitation relationships. We have suggested that the steeper and more depleted (relative to the modern theoretical gradient) meteoric sphaerosiderite N 18 O latitudinal gradient resulted from increased air mass rainout effects in coastal areas of the KWIB during the mid-Cretaceous. The sphaerosiderite isotopic data have been used to constrain a mass balance model of the Hydrologic Cycle in the northern hemisphere and to quantify precipitation rates of the equable ‘greenhouse’ Albian Stage in the KWIB. The mass balance model tracks the evolving isotopic composition of an air mass and its precipitation, and is driven by latitudinal temperature gradients. Our simulations indicate that significant increases in Albian precipitation (34^52%) and evaporation fluxes (76^96%) are required to reproduce the difference between modern and Albian meteoric siderite N 18 O latitudinal gradients. Calculations of precipitation rates from model outputs suggest mid^high latitude precipitation rates greatly exceeded modern rates (156^220% greater in mid latitudes [2600^3300 mm/yr], 99% greater at high latitudes [550 mm/yr]). The calculated precipitation rates are significantly different from the precipitation rates predicted by some recent general circulation models (GCMs) for the warm Cretaceous, particularly in the mid to high latitudes. Our mass balance model by no means replaces GCMs. However, it is a simple and effective means of obtaining quantitative data regarding the mid-Cretaceous Hydrologic Cycle in the KWIB. Our goal is to encourage the incorporation of isotopic tracers into GCM simulations of the midCretaceous, and to show how our empirical data and mass balance model estimates help constrain the boundary conditions.
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middle cretaceous greenhouse Hydrologic Cycle of north america
Geology, 2001Co-Authors: Timothy J White, Luis A Gonzalez, Greg A Ludvigson, Christopher J PoulsenAbstract:We present a paleolatitudinal precipitation reconstruction for the greenhouse setting of mid-latitude North America based on the oxygen isotopic composition of sphaerosiderites found in middle Cretaceous wetland paleosols. Our reconstructed middle Cretaceous d 18 O values of precipitation are ;4‰ less than values from comparable modern low-elevation coastal settings free of monsoons. The data fit a conceptual model in which the precipitation source for the eastern margin of the Cretaceous Western Interior Seaway of North America is an 18 O-enriched oceanic coastal jet. In this subtropical-tropical setting, midCretaceous precipitation rates are interpreted to range from ;2500 to ;4100 mm/yr.
Tadanobu Nakayama - One of the best experts on this subject based on the ideXlab platform.
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multiscaled analysis of hydrothermal dynamics in japanese megalopolis by using integrated approach
Hydrological Processes, 2012Co-Authors: Tadanobu Nakayama, Shizuka Hashimoto, Hiroyuki HamanoAbstract:We coupled the process-based National Integrated Catchment-based Eco-hydrology (NICE) model to an urban canopy model and the Regional Atmospheric Modeling System to simulate the effect of urban geometry and anthropogenic exhaustion on the hydrothermal changes in the atmosphere/land and the interfacial areas of the Japanese megalopolis. The simulation was conducted with multiscale in horizontally regional-urban-point levels and in vertically atmosphere–surface–unsaturated–saturated layers. The model reasonably reproduced the observed hydrothermal values by using ground-truth data in various types of natural/artificial land covers. The simulated results also suggested that the latent heat flux in the new water-holding pavement (consisting of porous asphalt and water-holding filler made of steel by-products based on silica compound) has a strong effect on Hydrologic Cycle and cooling temperature in comparison with the observed heat budget by newly incorporating the effect of water amount on the heat conductivity in the pavement. Furthermore, the model predicted the hydrothermal changes under two types of land cover scenarios to promote evaporation and to reduce air temperature against heat island phenomenon. Finally, we evaluated the relationship between the effect of groundwater use to ameliorate the heat island and the effect of infiltration on the water Cycle in the catchment. These procedures to integrate the multiscaled model simulation with political scenario based on the effective management of water resources as heat sink/source would be very powerful approaches for recovering a sound Hydrologic Cycle and for creating thermally pleasing environments in the megalopolis
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analysis of the ability of water resources to reduce the urban heat island in the tokyo megalopolis
Environmental Pollution, 2011Co-Authors: Tadanobu Nakayama, Shizuka HashimotoAbstract:Abstract Simulation procedure integrated with multi-scale in horizontally regional–urban-point levels and in vertically atmosphere–surface–unsaturated–saturated layers, was newly developed in order to predict the effect of urban geometry and anthropogenic exhaustion on the hydrothermal changes in the atmospheric/land and the interfacial areas of the Japanese megalopolis. The simulated results suggested that the latent heat flux in new water-holding pavement (consisting of porous asphalt and water-holding filler made of steel by-products based on silica compound) has a strong impact on Hydrologic Cycle and cooling temperature in comparison with the observed heat budget. We evaluated the relationship between the effect of groundwater use as a heat sink to tackle the heat island and the effect of infiltration on the water Cycle in the urban area. The result indicates that effective management of water resources would be powerful for ameliorating the heat island and recovering sound Hydrologic Cycle there.
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simulation of the effect of irrigation on the Hydrologic Cycle in the highly cultivated yellow river basin
Agricultural and Forest Meteorology, 2011Co-Authors: Tadanobu NakayamaAbstract:To account for complex and diverse water system involving river dry-up, groundwater degradation, agricultural/urban water use, and dam/canal effects in heavily irrigated Yellow River Basin, this study coupled NIES Integrated Catchment-based Eco-hydrology (NICE) model series with more complex sub-models involving various factors (NICE-DRY). The model reproduced reasonably evapotranspiration, irrigation water use, groundwater level, and river discharge during spring/winter wheat, summer maize, and summer rice cultivations. Scenario analysis predicted the impact of irrigation on both surface water and groundwater, which had previously been difficult to evaluate. The simulated discharge with irrigation was improved in terms of mean value, standard deviation, and coefficient of variation. Another scenario analysis of conversion from dryland to irrigated fields predicted that the effect of groundwater irrigation was predominant in the middle and downstream and the resultant groundwater degradation predominantly, where surface water was seriously limited. Simulated dry biomasses of wheat and maize were linearly related to Time-Integrated Normalized Difference Vegetation Index (TINDVI) estimated from satellite images. Temporal gradient of TINDVI during 1982–1999 showed spatially heterogeneous distribution and increasing trends in the wheat and maize fields, indicating that the production increases were related to irrigation water and the resultant Hydrologic changes. This integrated approach could help to estimate a close relationship between crop production, Hydrologic Cycle, and water availability, and predict heterogeneous vulnerability of water resources. Because this region experienced substantial river dry-up and groundwater degradation at the end of the 20th century, this approach would help to overcome substantial pressures of increasing food demand and declining water availability, and to decide on appropriate measures for whole water resources management to achieve sustainable development under sound socio-economic conditions.
