Simulations of snow distribution and hydrology in a mountain basin

We applied a version of the Regional Hydro‐Ecologic Simulation System (RHESSys) that implements snow redistribution, elevation partitioning, and wind‐driven sublimation to Loch Vale Watershed (LVWS), an alpine‐subalpine Rocky Mountain catchment where snow accumulation and ablation dominate the hydrologic cycle. We compared simulated discharge to measured discharge and the simulated snow distribution to photogrammetrically rectified aerial (remotely sensed) images. Snow redistribution was governed by a topographic similarity index. We subdivided each hillslope into elevation bands that had homogeneous climate extrapolated from observed climate. We created a distributed wind speed field that was used in conjunction with daily measured wind speeds to estimate sublimation. Modeling snow redistribution was critical to estimating the timing and magnitude of discharge. Incorporating elevation partitioning improved estimated timing of discharge but did not improve patterns of snow cover since wind was the dominant controller of areal snow patterns. Simulating wind‐driven sublimation was necessary to predict moisture losses

EFFECTS OF LAND COVER, WATER REDISTRIBUTION, AND TEMPERATURE ON ECOSYSTEM PROCESSES IN THE SOUTH PLATTE BASIN

Over one‐third of the land area in the South Platte Basin of Colorado, Nebraska, and Wyoming, has been converted to croplands. Irrigated cropland now comprises 8% of the basin, while dry croplands make up 31%. We used the RHESSys model to compare the changes in plant productivity and vegetation‐related hydrological processes that occurred as a result of either land cover alteration or directional temperature changes (−2°C, +4°C). Land cover change exerted more control over annual plant productivity and water fluxes for converted grasslands, while the effect of temperature changes on productivity and water fluxes was stronger in the mountain vegetation. Throughout the basin, land cover change increased the annual loss of water to the atmosphere by 114 mm via evaporation and transpiration, an increase of 37%. Both irrigated and nonirrigated grains became active earlier in the year than shortgrass steppe, leading to a seasonal shift in water losses to the atmosphere. Basin‐wide photosynthesis increased by 80% due to grain production. In contrast, a 4°C warming scenario caused annual transpiration to increase by only 3% and annual evaporation to increase by 28%, for a total increase of 71 mm. Warming decreased basin‐wide photosynthesis by 16%. There is a large elevational range from east to west in the South Platte Basin, which encompasses the western edge of the Great Plains and the eastern front of the Rocky Mountains. This elevational gain is accompanied by great changes in topographic complexity, vegetation type, and climate. Shortgrass steppe and crops found at elevations between 850 and 1800 m give way to coniferous forests and tundra between 1800 and 4000 m. Climate is increasingly dominated by winter snow precipitation with increasing elevation, and the timing of snowmelt influences tundra and forest ecosystem productivity, soil moisture, and downstream discharge. Mean annual precipitation of \u3c500 mm on the plains below 1800 m is far less than potential evapotranspiration of 1000–1500 mm and is insufficient for optimum plant productivity. The changes in water flux and photosynthesis from conversion of steppe to cropland are the result of redistribution of snowmelt water from the mountains and groundwater pumping through irrigation projects

Mapping Regional Forest Evapotranspiration and Photosynthesis by Coupling Satellite Data with Ecosystem Simulation

Mapping Regional Forest Evapotranspiration and Photosynthesis by Coupling Satellite Data With Ecosystem Simulatio

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Genomic Dissection of Bipolar Disorder and Schizophrenia, Including 28 Subphenotypes

publisher: Elsevier articletitle: Genomic Dissection of Bipolar Disorder and Schizophrenia, Including 28 Subphenotypes journaltitle: Cell articlelink: https://doi.org/10.1016/j.cell.2018.05.046 content_type: article copyright: © 2018 Elsevier Inc

Automating object representation of drainage basins

A computer program written in “C” and designed to build a geomorphometric database of a drainage basin is given. The program operates on a raster representation of the stream network structure that may be derived from a number of previously presented approaches. An operational model of drainage basin structure is employed to recognize basic geomorphic objects and to compute their spatial and functional interrelationships. The resulting database may serve the purpose of automating geomorphometric analysis or may provide a framework for automating the construction of a high-level object oriented database model of the surface from more detailed, lower level data planes

Forest ecosystem processes at the watershed scale: incorporating hillslope hydrology

An approach to distributed modeling of watershed hydro-ecological processes over large spatial scales is described. A data and simulation system, RHESSys (Regional HydroEcological Simulation System), combines a set of remote sensing/GIS techniques with integrated hydrological and ecological models in order to automate the parameterization and simulation of a suite of ecological and hydrological flux and storage processes through the watershed. Specifically, we simulate forest canopy net photosynthesis (PSN) and total evapotranspiration (ET) through the year with a modeling package that integrates FORESTBGC, a stand level model of forest carbon, water and nitrogen budgets, with TOPMODEL, a quasi-distributed hydrological model. The latter model introduces the effects of hillslope hydrological processes, incorporating surface redistribution of soil water by saturated throughflow processes. The maintainance of regular patterns of soil water by throughflow processes cause forest ecosystem activity to vary dependent on hillslope position. The distributed framework is based on a terrain partition in which each terrain object (hillslopes and stream reaches) comprising the watershed are separately parameterized and simulated. The location of each terrain object within the watershed is explicitly represented while the internal variability of each object is represented as a joint parameter distribution. Generalization of the surface into different numbers of terrain objects (by growing or shrinking the extent of the stream network) is automatically accomplished using digital terrain data. This allows us to flexibly alter the spatial representation of the watershed by shifting surface information either into the internal hillslope parameter distributions or into greater numbers of hillslopes (and stream reaches). Limited simulations of a mountainous watershed in western Montana indicate that incorporation of within hillslope throughflow and the soil, topography and vegetation distribution has the effect of significantly altering the seasonal PSN and ET trends in comparison with lumped surface representations without lateral water flux