Surface water

About: Surface water is a research topic. Over the lifetime, 25507 publications have been published within this topic receiving 613520 citations. The topic is also known as: water on surface & onground water.

A simple hydrologically based model of land surface water and energy fluxes for general circulation models

Abstract: A generalization of the single soil layer variable infiltration capacity (VIC) land surface hydrological model previously implemented in the Geophysical Fluid Dynamics Laboratory (GFDL) general circulation model (GCM) is described. The new model is comprised of a two-layer characterization of the soil column, and uses an aerodynamic representation of the latent and sensible heat fluxes at the land surface. The infiltration algorithm for the upper layer is essentially the same as for the single layer VIC model, while the lower layer drainage formulation is of the form previously implemented in the Max-Planck-Institut GCM. The model partitions the area of interest (e.g., grid cell) into multiple land surface cover types; for each land cover type the fraction of roots in the upper and lower zone is specified. Evapotranspiration consists of three components: canopy evaporation, evaporation from bare soils, and transpiration, which is represented using a canopy and architectural resistance formulation. Once the latent heat flux has been computed, the surface energy balance is iterated to solve for the land surface temperature at each time step. The model was tested using long-term hydrologic and climatological data for Kings Creek, Kansas to estimate and validate the hydrological parameters, and surface flux data from three First International Satellite Land Surface Climatology Project Field Experiment (FIFE) intensive field campaigns in the summer-fall of 1987 to validate the surface energy fluxes.

Mechanisms Controlling World Water Chemistry

Abstract: On the basis of analytical chemical data for numerous rain, river, lake, and ocean samples, the three major mechanisms controlling world surface water chemistry can be defined as atmospheric precipitation, rock dominance, and the evaporation-crystallization process.

The geochemistry of natural waters

Abstract: 1 The Hydrologic Cycle 2 Chemical Background 3 Organic Compounds in Natural Waters 4 The Carbonate System and pH Control 5 Clay Minerals and Ion Exchange 6 Stability Relationships and Silicate Equilibria 7 Kinetics 8 Weathering and Water Chemistry, I: Principles 9 Weathering and Water Chemistry, II: Examples 10 Acid Deposition and Surface Water Chemistry 11 Evaporation and Saline Waters 12 The Oceans 13 Redox Equilibria 14 Redox Conditions in Natural Waters 15 Trace Elements 16 Mathematical and Numerical Models 17 Isotopes Appendices

High-resolution mapping of global surface water and its long-term changes

Abstract: A freely available dataset produced from three million Landsat satellite images reveals substantial changes in the distribution of global surface water over the past 32 years and their causes, from climate change to human actions. The distribution of surface water has been mapped globally, and local-to-regional studies have tracked changes over time. But to date, there has been no global and methodologically consistent quantification of changes in surface water over time. Jean-Francois Pekel and colleagues have analysed more than three million Landsat images to quantify month-to-month changes in surface water at a resolution of 30 metres and over a 32-year period. They find that surface waters have declined by almost 90,000 square kilometres—largely in the Middle East and Central Asia—but that surface waters equivalent to about twice that area have been created elsewhere. Drought, reservoir creation and water extraction appear to have driven most of the changes in surface water over the past decades. The location and persistence of surface water (inland and coastal) is both affected by climate and human activity1 and affects climate2,3, biological diversity4 and human wellbeing5,6. Global data sets documenting surface water location and seasonality have been produced from inventories and national descriptions7, statistical extrapolation of regional data8 and satellite imagery9,10,11,12, but measuring long-term changes at high resolution remains a challenge. Here, using three million Landsat satellite images13, we quantify changes in global surface water over the past 32 years at 30-metre resolution. We record the months and years when water was present, where occurrence changed and what form changes took in terms of seasonality and persistence. Between 1984 and 2015 permanent surface water has disappeared from an area of almost 90,000 square kilometres, roughly equivalent to that of Lake Superior, though new permanent bodies of surface water covering 184,000 square kilometres have formed elsewhere. All continental regions show a net increase in permanent water, except Oceania, which has a fractional (one per cent) net loss. Much of the increase is from reservoir filling, although climate change14 is also implicated. Loss is more geographically concentrated than gain. Over 70 per cent of global net permanent water loss occurred in the Middle East and Central Asia, linked to drought and human actions including river diversion or damming and unregulated withdrawal15,16. Losses in Australia17 and the USA18 linked to long-term droughts are also evident. This globally consistent, validated data set shows that impacts of climate change and climate oscillations on surface water occurrence can be measured and that evidence can be gathered to show how surface water is altered by human activities. We anticipate that this freely available data will improve the modelling of surface forcing, provide evidence of state and change in wetland ecotones (the transition areas between biomes), and inform water-management decision-making.

Satellite-based estimates of groundwater depletion in India

Abstract: Groundwater is a primary source of fresh water in many parts of the world. Some regions are becoming overly dependent on it, consuming groundwater faster than it is naturally replenished and causing water tables to decline unremittingly 1 . Indirect evidencesuggeststhatthisisthecaseinnorthwestIndia 2 ,butthere has been no regional assessment of the rate of groundwater depletion. Here we use terrestrial water storage-change observations from the NASA Gravity Recovery and Climate Experiment satellites 3 and simulated soil-water variations from a dataintegrating hydrological modelling system 4 to show that groundwater is being depleted at a mean rate of 4.0 61.0cmyr 21 equivalent height of water (17.7 64.5km 3 yr 21 ) over the Indian states