scholarly journals Creating long term gridded fields of reference evapotranspiration in Alpine terrain based on a re-calibrated Hargreaves method

2015 ◽  
Vol 12 (5) ◽  
pp. 5055-5082
Author(s):  
K. Haslinger ◽  
A. Bartsch
Keyword(s):  
High Resolution ◽  
Reference Evapotranspiration ◽  
Grid Point ◽  
Temperature Fields ◽  
Time Step ◽  
Maximum Temperatures ◽  
Order Spline ◽  
Elevation Model ◽  
Mean Square Errors ◽  
Daily Time

Abstract. A new approach for the construction of high resolution gridded fields of reference evapotranspiration for the Austrian domain on a daily time step is presented. Forcing fields of gridded data of minimum and maximum temperatures are used to estimate reference evapotranspiration based on the formulation of Hargreaves. The calibration constant in the Hargreaves equation is recalibrated to the Penman–Monteith equation, which is recommended by the FAO, in a monthly and station-wise assessment. This ensures on one hand eliminated biases of the Hargreaves approach compared to the formulation of Penman–Monteith and on the other hand also reduced root mean square errors and relative errors on a daily time scale. The resulting new calibration parameters are interpolated in time to a daily temporal resolution for a standard year of 365 days. The overall novelty of the approach is the conduction of surface elevation as a predictor to estimate the re-calibrated Hargreaves parameter in space. A third order spline is fitted to the re-calibrated parameters against elevation at every station and yields the statistical model for assessing these new parameters in space by using the underlying digital elevation model of the temperature fields. Having newly calibrated parameters for every day of year and every grid point, the Hargreaves method is applied to the temperature fields, yielding reference evapotranspiration for the entire grid and time period from 1961–2013. With this approach it is possible to generate high resolution reference evapotranspiration fields starting when only temperature observations are available but re-calibrated to meet the requirements of the recommendations defined by the FAO.

scholarly journals Creating long-term gridded fields of reference evapotranspiration in Alpine terrain based on a recalibrated Hargreaves method

2016 ◽  
Vol 20 (3) ◽  
pp. 1211-1223 ◽  
Author(s):  
Klaus Haslinger ◽  
Annett Bartsch
Keyword(s):  
High Resolution ◽  
Reference Evapotranspiration ◽  
Grid Point ◽  
Temperature Fields ◽  
Time Step ◽  
Digital Elevation ◽  
Maximum Temperatures ◽  
Elevation Model ◽  
Relative Errors ◽  
Mean Square Errors

Abstract. A new approach for the construction of high-resolution gridded fields of reference evapotranspiration for the Austrian domain on a daily time step is presented. Gridded data of minimum and maximum temperatures are used to estimate reference evapotranspiration based on the formulation of Hargreaves. The calibration constant in the Hargreaves equation is recalibrated to the Penman–Monteith equation in a monthly and station-wise assessment. This ensures, on one hand, eliminated biases of the Hargreaves approach compared to the formulation of Penman–Monteith and, on the other hand, also reduced root mean square errors and relative errors on a daily timescale. The resulting new calibration parameters are interpolated over time to a daily temporal resolution for a standard year of 365 days. The overall novelty of the approach is the use of surface elevation as the only predictor to estimate the recalibrated Hargreaves parameter in space. A third-order polynomial is fitted to the recalibrated parameters against elevation at every station which yields a statistical model for assessing these new parameters in space by using the underlying digital elevation model of the temperature fields. With these newly calibrated parameters for every day of year and every grid point, the Hargreaves method is applied to the temperature fields, yielding reference evapotranspiration for the entire grid and time period from 1961–2013. This approach is opening opportunities to create high-resolution reference evapotranspiration fields based only temperature observations, but being as close as possible to the estimates of the Penman–Monteith approach.

Comparison of sum-of-hourly and daily time step standardized ASCE Penman-Monteith reference evapotranspiration

2017 ◽  
Vol 134 (1-2) ◽  
pp. 533-543 ◽  
Author(s):  
Koffi Djaman ◽  
Suat Irmak ◽  
Mamadou Sall ◽  
Abdoulaye Sow ◽  
Isa Kabenge
Keyword(s):  
Reference Evapotranspiration ◽  
Time Step ◽  
Daily Time Step ◽  
Daily Time

scholarly journals Assessment of High Resolution Air Temperature Fields at Rocky Mountain National Park by Combining Scarce Point Measurements with Elevation and Remote Sensing Data

2020 ◽  
Vol 13 (1) ◽  
pp. 113
Author(s):  
Antonio-Juan Collados-Lara ◽  
Steven R. Fassnacht ◽  
Eulogio Pardo-Igúzquiza ◽  
David Pulido-Velazquez
Keyword(s):  
Remote Sensing ◽  
High Resolution ◽  
Air Temperature ◽  
Land Surface ◽  
National Park ◽  
Rocky Mountain ◽  
Rocky Mountain National Park ◽  
Temperature Fields ◽  
Lapse Rate ◽  
Validation Experiment

There is necessity of considering air temperature to simulate the hydrology and management within water resources systems. In many cases, a big issue is considering the scarcity of data due to poor accessibility and limited funds. This paper proposes a methodology to obtain high resolution air temperature fields by combining scarce point measurements with elevation data and land surface temperature (LST) data from remote sensing. The available station data (SNOTEL stations) are sparse at Rocky Mountain National Park, necessitating the inclusion of correlated and well-sampled variables to assess the spatial variability of air temperature. Different geostatistical approaches and weighted solutions thereof were employed to obtain air temperature fields. These estimates were compared with two relatively direct solutions, the LST (MODIS) and a lapse rate-based interpolation technique. The methodology was evaluated using data from different seasons. The performance of the techniques was assessed through a cross validation experiment. In both cases, the weighted kriging with external drift solution (considering LST and elevation) showed the best results, with a mean squared error of 3.7 and 3.6 °C2 for the application and validation, respectively.

Line of Sight Analysis 

2021 ◽  
Author(s):  
Emily Law ◽  
Natalie Gallegos ◽  
Shan Malhotra
Keyword(s):  
High Resolution ◽  
Solar System ◽  
High Gain ◽  
Line Of Sight ◽  
Time Intervals ◽  
Ground Station ◽  
Points Of Interest ◽  
Digital Elevation ◽  
Initial Release ◽  
Elevation Model

<p>The Line of Sight (LoS) is one of the latest tools to join the analytics suite of tools for the Solar System Treks (https://trek.nasa.gov) portals.  The LoS tool provides a way to compute visibility between the entities in our solar system. More concretely, this utility searches for windows of communication or a “line of sight” between any two entities. Entities include orbiters, rovers, planetary bodies, ground stations, and other topographical locations. In addition to establishing communications between the two entities, the tool also takes into account local terrains of the entities in question.</p> <p>The software seeks to answer questions about establishing communications between a rover and an orbiter, or an orbiter to a ground station. In mission planning, LoS can be used to determine possible traverses for a rover that must maintain communications with a lander, or find time intervals of communication to an orbiter when a rover or lander are near an obstructing surface feature such as a crater rim or mound. Computations can be even more granular and lines of sight can be computed between mission instruments, thus allowing to ask questions such as “Is the High Gain Antenna on a rover visible from an orbiter?”</p> <p>The initial release of the software focuses on the lunar surface and the LRO spacecraft. Users can ask whether a topographical location on the moon is visible from the orbiter or a discrete set of ground stations on Earth. The tool uses NAIF SPICE and various mission kernels for computing planetary geometries. LoS also uses high resolution Digital Elevation Model (DEM) to model the terrain surrounding the points of interest. In-house software is used to convert high resolution DEMs into a format compatible with the tool. Users can provide their own DEMs to model the terrain on different topographical locations to use for their own computations.</p>

scholarly journals Low cost, multiscale and multi-sensor application for flooded areas mapping

2017 ◽  
Author(s):  
Daniele Giordan ◽  
Davide Notti ◽  
Alfredo Villa ◽  
Francesco Zucca ◽  
Fabiana Calò ◽  
...  
Keyword(s):  
High Resolution ◽  
Low Cost ◽  
Essential Elements ◽  
Basin Scale ◽  
High Resolution Images ◽  
Maximum Water ◽  
Urbanized Areas ◽  
Flooded Area ◽  
Elevation Model ◽  
Flooded Areas

Abstract. Flood mapping and estimation of maximum water depth are essential elements for a first damages evaluation, civil protection interventions planning and detection of areas where remedial are more needed. In this work, we present and discuss a methodology for mapping and quantifying flood severity over plain areas. The proposed methodology considers a multiscale and multi-sensor approach using free or low-cost data/sensors. We applied this method to November 2016 Piemonte (NW Italy) flood. We first mapped flooded areas at basin scale using free satellite data from low to medium-high resolution using both SAR (Sentinel-1, Cosmo-Skymed) and multispectral sensors (MODIS, Sentinel-2). Using very- and ultra- high-resolution images from the low-cost aerial platform and Remotely Piloted Aerial System, we refined the flooded zone, and we detected the most damaged sector. The presented method considers both urbanized and not urbanized areas. Nadiral images have several limitations in particular in urbanized areas, where the use of terrestrial images solved this limitation. Very- and ultra-high resolution images have been processed with Structure from Motion (SfM) for the realization of 3-D models. These data, combined with available digital elevation model, allowed us to obtain maps of flooded area, maximum water high and damaged infrastructures.

scholarly journals Continuous high-resolution midlatitude-belt simulations for July–August 2013 with WRF

2017 ◽  
Vol 10 (5) ◽  
pp. 2031-2055 ◽  
Author(s):  
Thomas Schwitalla ◽  
Hans-Stefan Bauer ◽  
Volker Wulfmeyer ◽  
Kirsten Warrach-Sagi
Keyword(s):  
High Resolution ◽  
Land Surface ◽  
Large Scale ◽  
Temperature Fields ◽  
Surface Model ◽  
Limited Area ◽  
Data Set ◽  
Latitude Belt ◽  
Simulated Precipitation ◽  
The Impact

Abstract. Increasing computational resources and the demands of impact modelers, stake holders, and society envision seasonal and climate simulations with the convection-permitting resolution. So far such a resolution is only achieved with a limited-area model whose results are impacted by zonal and meridional boundaries. Here, we present the setup of a latitude-belt domain that reduces disturbances originating from the western and eastern boundaries and therefore allows for studying the impact of model resolution and physical parameterization. The Weather Research and Forecasting (WRF) model coupled to the NOAH land–surface model was operated during July and August 2013 at two different horizontal resolutions, namely 0.03 (HIRES) and 0.12° (LOWRES). Both simulations were forced by the European Centre for Medium-Range Weather Forecasts (ECMWF) operational analysis data at the northern and southern domain boundaries, and the high-resolution Operational Sea Surface Temperature and Sea Ice Analysis (OSTIA) data at the sea surface.The simulations are compared to the operational ECMWF analysis for the representation of large-scale features. To analyze the simulated precipitation, the operational ECMWF forecast, the CPC MORPHing (CMORPH), and the ENSEMBLES gridded observation precipitation data set (E-OBS) were used as references.Analyzing pressure, geopotential height, wind, and temperature fields as well as precipitation revealed (1) a benefit from the higher resolution concerning the reduction of monthly biases, root mean square error, and an improved Pearson skill score, and (2) deficiencies in the physical parameterizations leading to notable biases in distinct regions like the polar Atlantic for the LOWRES simulation, the North Pacific, and Inner Mongolia for both resolutions.In summary, the application of a latitude belt on a convection-permitting resolution shows promising results that are beneficial for future seasonal forecasting.

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