scholarly journals Comparison of daily potential evapotranspiration calculated by two procedures based on Penman-Monteith type equation

2013 ◽  
Vol 61 (2) ◽  
pp. 173-176 ◽  
Author(s):  
Hana Hlaváčiková ◽  
Viliam Novák
Keyword(s):  
Potential Evapotranspiration ◽  
Meteorological Data ◽  
Aerodynamic Resistance ◽  
Type Equation ◽  
Simulation Models ◽  
Estimation Methods ◽  
Net Radiation ◽  
Water Simulation ◽  
Reference Crop ◽  
Hydrus 1D

Abstract Paper presents comparison of the daily reference crop (grass vegetation cover) potential evapotranspiration results calculated by the two modifications of the Penman-Monteith type equation. The first modification was published in FAO recommendation (Allen at al., 1998), PM-FAO, the second is modification according to Budagovskiy (1964) and Novák (1995), PM-BN. Both are used in soil water simulation models HYDRUS-1D and GLOBAL. Calculations were performed for frost-free seasons of the years 2000-2009, using the meteorological station Gabčíkovo (South Slovakia) meteorological data and canopy characteristics. The results indicate significant differences in daily and seasonal potential evapotranspiration. Reasons for those differences are discussed; they should be in different net radiation and aerodynamic resistance estimation methods.

scholarly journals Estimation of evapotranspiration rate by using the Penman–Monteith and Hargreaves formulas for the loess in Northeast Bulgaria complex with HYDRUS-1D

2019 ◽  
Vol 48 (3) ◽  
pp. 3-9
Author(s):  
Peter Gerginov ◽  
Dimitar Antonov
Keyword(s):  
Potential Evapotranspiration ◽  
Meteorological Data ◽  
Danube River ◽  
Near Surface ◽  
The North ◽  
Evapotranspiration Rate ◽  
Scientific Project ◽  
Unsaturated Zones ◽  
The Impact ◽  
Hydrus 1D

Loess and loess-like sediments cover approximately 13% of the Bulgarian territory, mainly within the Danubian plain. From the Danube River to the Fore-Balkan, the loess soils form a loess complex where its depth varies from 50–60 meters in the north to few meters in the south, respectively. Widespread loess sediments possess a specific feature: they typically form deep unsaturated zones. Quantification of the near surface water balance is extremely important for evaluating land-atmosphere interactions, and the impact of land-use change on the subsurface flow and the evapotranspiration rate is an essential term in this quantification. In the frames of a scientific project, an automatic weather station was installed in a typical plain terrain of the loess complex in Northeast Bulgaria, recording meteorological data from September 2015 to February 2017. This study provides a mathematical description of processes (i.e., Penman-Monteith and Hargreaves Methods) used to estimate daily evapotranspiration rates implemented into the numerical model HYDRUS-1D, as well as a respective rate investigation of months with and without intensive rainfalls. Overall results indicate that using the Hargreaves formula for evaluation of the potential evapotranspiration leads to overestimation between 10% and 20%, respectively for a “wet” and “dry” month.

scholarly journals Modelling Actual Evapotranspiration Seasonal Variability by Meteorological Data-Based Models

Hydrology ◽  
2020 ◽  
Vol 7 (3) ◽  
pp. 50 ◽  
Author(s):  
Mirka Mobilia ◽  
Marius Schmidt ◽  
Antonia Longobardi
Keyword(s):  
Prediction Models ◽  
Potential Evapotranspiration ◽  
Meteorological Data ◽  
Threshold Value ◽  
Heat Fluxes ◽  
Actual Evapotranspiration ◽  
Net Radiation ◽  
Antecedent Precipitation ◽  
Annual Dynamic ◽  
Eddy Covariance Measurements

This study aims at illustrating a methodology for predicting monthly scale actual evapotranspiration losses only based on meteorological data, which mimics the evapotranspiration intra-annual dynamic. For this purpose, micrometeorological data at the Rollesbroich and Bondone mountain sites, which are energy-limited systems, and the Sister site, a water-limited system, have been analyzed. Based on an observed intra-annual transition between dry and wet states governed by a threshold value of net radiation at each site, an approach that couples meteorological data-based potential evapotranspiration and actual evapotranspiration relationships has been proposed and validated against eddy covariance measurements, and further compared to two well-known actual evapotranspiration prediction models, namely the advection-aridity and the antecedent precipitation index models. The threshold approach improves the intra-annual actual evapotranspiration variability prediction, particularly during the wet state periods, and especially concerning the Sister site, where errors are almost four times smaller compared to the basic models. To further improve the prediction within the dry state periods, a calibration of the Priestley-Taylor advection coefficient was necessary. This led to an error reduction of about 80% in the case of the Sister site, of about 30% in the case of Rollesbroich, and close to 60% in the case of Bondone Mountain. For cases with a lack of measured data of net radiation and soil heat fluxes, which are essential for the implementation of the models, an application derived from empirical relationships is discussed. In addition, the study assessed whether this variation from meteorological data worsened the prediction performances of the models.

scholarly journals Sensitivity of groundwater recharge using climatic analogues and HYDRUS-1D

2012 ◽  
Vol 16 (8) ◽  
pp. 2485-2497 ◽  
Author(s):  
B. Leterme ◽  
D. Mallants ◽  
D. Jacques
Keyword(s):  
Water Balance ◽  
Groundwater Recharge ◽  
Potential Evapotranspiration ◽  
Future Climate ◽  
Annual Precipitation ◽  
Balance Model ◽  
Subtropical Climate ◽  
Northern Spain ◽  
Near Surface ◽  
Hydrus 1D

Abstract. The sensitivity of groundwater recharge to different climate conditions was simulated using the approach of climatic analogue stations, i.e. stations presently experiencing climatic conditions corresponding to a possible future climate state. The study was conducted in the context of a safety assessment of a future near-surface disposal facility for low and intermediate level short-lived radioactive waste in Belgium; this includes estimation of groundwater recharge for the next millennia. Groundwater recharge was simulated using the Richards based soil water balance model HYDRUS-1D and meteorological time series from analogue stations. This study used four analogue stations for a warmer subtropical climate with changes of average annual precipitation and potential evapotranspiration from −42% to +5% and from +8% to +82%, respectively, compared to the present-day climate. Resulting water balance calculations yielded a change in groundwater recharge ranging from a decrease of 72% to an increase of 3% for the four different analogue stations. The Gijon analogue station (Northern Spain), considered as the most representative for the near future climate state in the study area, shows an increase of 3% of groundwater recharge for a 5% increase of annual precipitation. Calculations for a colder (tundra) climate showed a change in groundwater recharge ranging from a decrease of 97% to an increase of 32% for four different analogue stations, with an annual precipitation change from −69% to −14% compared to the present-day climate.

Use of Soil Survey Data for Regional Soil Water Simulation Models

1985 ◽  
Vol 49 (5) ◽  
pp. 1238-1244 ◽  
Author(s):  
J. H. M. Wösten ◽  
J. Bouma ◽  
G. H. Stoffelsen
Keyword(s):  
Soil Water ◽  
Survey Data ◽  
Simulation Models ◽  
Soil Survey ◽  
Water Simulation

Analysis and Simulation of Low Speed Sensorless Vector Control with Two Current Signal Injection Schemes

2013 ◽  
Vol 722 ◽  
pp. 361-368
Author(s):  
Yu Dong Li ◽  
Bo Zhou ◽  
Ying Liu ◽  
Cheng Liang Zhao
Keyword(s):  
Vector Control ◽  
Permanent Magnet Synchronous Motor ◽  
Low Frequency ◽  
Simulation Models ◽  
Position Estimation ◽  
Estimation Methods ◽  
Current Signal ◽  
Rotor Position ◽  
Sensorless Vector Control ◽  
Signal Injection

Two current signal injection methods, the fluctuating high frequency (HF) current signal injection and low frequency (LF) current signal injection, were discussed. The basic principles of rotor position self-sensing using these current signal injection and the key techniques in implementation were presented and the simulation models for sensorless vector control systems of a permanent magnet synchronous motor (PMSM) were established using two proposed rotor position estimation methods. Comparative simulation study of the fluctuating HF current signal injection and LF current signal injection was investigated, and draw the conclusions that the saliency-tracking scheme using fluctuating HF current signal injection possesses simpler configuration and better speed-adjustable performance both in static and dynamic.

Quantitative estimation on contribution of climate changes and watershed characteristic changes to decreasing streamflow in the Huangshui Basin, China

2021 ◽  
Author(s):  
Xizhi Lv ◽  
Shaopeng Li ◽  
Yongxin Ni ◽  
Qiufen Zhang ◽  
Li Ma
Keyword(s):  
Water Resources ◽  
Climate Changes ◽  
Yellow River ◽  
Potential Evapotranspiration ◽  
Quantitative Estimation ◽  
Meteorological Data ◽  
Characteristic Parameter ◽  
Research Area ◽  
Watershed Characteristic ◽  
Streamflow Change

<p>In the past 60 years, climate changes and underlying surface of the watershed have affected the structure and characteristics of water resources to a different degree It is of great significance to investigate main drivers of streamflow change for development, utilization and planning management of water resources in river basins. In this study, the Huangshui Basin, a typical tributary of the upper Yellow River, is used as the research area. Based on the Budyko hypothesis, streamflow and meteorological data from 1958-2017 are used to quantitatively assess the relative contributions of changes in climate and watershed characteristic to streamflow change in research area. The results show that: the streamflow of Huangshui Basin shows an insignificant decreasing trend; the sensitivity coefficients of streamflow to precipitation, potential evapotranspiration and watershed characteristic parameter are 0.5502, -0.1055, and 183.2007, respectively. That is, an increase in precipitation by 1 unit will induce an increase of 0.5502 units in streamflow, and an increase in potential evapotranspiration by 1 unit will induce a decrease of 0.1055 units in streamflow, and an increase in the watershed characteristic parameter by 1 unit will induce a decrease of 183.2007 units in streamflow. Compared with the reference period (1958-1993), the streamflow decreased by 20.48mm (13.59%) during the change period (1994-2017), which can be attribution to watershed characteristic changes (accounting for 73.64%) and climate change (accounting for 24.48%). Watershed characteristic changes exert a dominant influence upon the reduction of streamflow in the Huangshui Basin.</p>

scholarly journals Reference evapotranspiration for Londrina, Paraná, Brazil: performance of different estimation methods

2017 ◽  
Vol 38 (4Supl1) ◽  
pp. 2363
Author(s):  
Rodrigo Dlugosz da Silva ◽  
Marcelo Augusto de Aguiar e Silva ◽  
Marcelo Giovanetti Canteri ◽  
Juliandra Rodrigues Rosisca ◽  
Nilson Aparecido Vieira Junior
Keyword(s):  
Reference Evapotranspiration ◽  
Meteorological Data ◽  
Global Radiation ◽  
Alternative Methods ◽  
Estimation Methods ◽  
Performance Indices ◽  
Excellent Performance ◽  
Study Region ◽  
Temperature Radiation ◽  
And Performance

Aiming at assessing the performance of alternative methods to Penman-Monteith FAO56 for estimating the reference evapotranspiration (ETo) for Londrina, Paraná, Brazil, the methods temperature radiation, Hicks-Hess, Hargreaves-Samani (1982), Turc, Priestley-Taylor, Tanner-Pelton, Jensen-Haise, Makkink, modified Hargreaves, Stephens-Stewart, Abtew, global radiation, Ivanov, Lungeon, Hargreaves-Samani (1985), Benavides-Lopez, original Penman, Linacre, Blaney-Morin, Romanenko, Hargreaves (1974), McCloud, Camargo, Hamon, Kharrufa, McGuiness-Bordne, and Blaney-Criddle were compared to that standard method recommended by FAO. The estimations were correlated by linear regression and assessed by using the Person’s correlation coefficient (r), concordance index (d), and performance index (c) using a set of meteorological data of approximately 40 years. The methods modified Hargreaves, Stephens-Stewart, Abtew, global radiation, Ivanov, Lungeon, Hargreaves-Samani (1985), Benavides-Lopez, original Penman, and Linacre should be avoided, as they did not present excellent results. The methods McCloud, Camargo, Hamon, Kharrufa, McGuinness-Bordne, Blaney-Criddle, Hargreaves (1974), Romanenko, and Blaney-Morin were classified as very bad, not being recommended. In contrast, the methods temperature radiation, Hicks-Hess, Hargreaves-Samani (1982), Turc, Priestley-Taylor, Tenner-Pelton, Jensen-Haise, and Makkink presented excellent performance indices and can be applied in the study region.

scholarly journals Summer drought in Switzerland 1981‒2020: Events, trends and drivers

2021 ◽  
Author(s):  
Simon C. Scherrer ◽  
Christoph Spirig ◽  
Martin Hirschi ◽  
Felix Maurer ◽  
Sven Kotlarski
Keyword(s):  
Regional Climate Model ◽  
Soil Water ◽  
Climate Model ◽  
Potential Evapotranspiration ◽  
Meteorological Data ◽  
Regional Climate ◽  
Reanalysis Data ◽  
Summer Drought ◽  
Temperature And Precipitation ◽  
Temperature Scaling

<p>The Alpine region has recently experienced several dry summers with negative impacts on the economy, society and ecology. Here, soil water, evapotranspiration and meteorological data from several observational and model-based data sources is used to assess events, trends and drivers of summer drought in Switzerland in the period 1981‒2020. 2003 and 2018 are identified as the driest summers followed by somewhat weaker drought conditions in 2020, 2015 and 2011. We find clear evidence for an increasing summer drying in Switzerland. The observed climatic water balance (-39.2 mm/decade) and 0-1 m soil water from reanalysis (ERA5-Land: -4.7 mm/decade; ERA5: -7.2 mm/decade) show a clear tendency towards summer drying with decreasing trends in most months. Increasing evapotranspiration (potential evapotranspiration: +21.0 mm/decade; ERA5-Land actual evapotranspiration: +15.1 mm/decade) is identified as important driver which scales excellently (+4 to +7%/K) with the observed strong warming of about 2°C. An insignificant decrease in precipitation further enhanced the tendency towards drier conditions. Most simulations of the EURO-CORDEX regional climate model ensemble underestimate the changes in summer drying. They underestimate both, the observed recent summer warming and the small decrease in precipitation. The changes in temperature and precipitation are negatively correlated, i.e. simulations with stronger warming tend to show (weak) decreases in precipitation. However, most simulations and the reanalysis overestimate the correlation between temperature and precipitation and the precipitation-temperature scaling on the interannual time scale. Our results emphasize that the analysis of the regional summer drought evolution and its drivers remains challenging especially with regional climate model data but considerable uncertainties also exist in reanalysis data sets.</p>

scholarly journals Reference evapotranspiration for Londrina, Paraná, Brazil: performance of different estimation methods

2017 ◽  
Vol 38 (4Supl1) ◽  
pp. 2363
Author(s):  
Rodrigo Dlugosz da Silva ◽  
Marcelo Augusto de Aguiar e Silva ◽  
Marcelo Giovanetti Canteri ◽  
Juliandra Rodrigues Rosisca ◽  
Nilson Aparecido Vieira Junior
Keyword(s):  
Reference Evapotranspiration ◽  
Meteorological Data ◽  
Global Radiation ◽  
Alternative Methods ◽  
Estimation Methods ◽  
Performance Indices ◽  
Excellent Performance ◽  
Study Region ◽  
Temperature Radiation ◽  
And Performance

Aiming at assessing the performance of alternative methods to Penman-Monteith FAO56 for estimating the reference evapotranspiration (ETo) for Londrina, Paraná, Brazil, the methods temperature radiation, Hicks-Hess, Hargreaves-Samani (1982), Turc, Priestley-Taylor, Tanner-Pelton, Jensen-Haise, Makkink, modified Hargreaves, Stephens-Stewart, Abtew, global radiation, Ivanov, Lungeon, Hargreaves-Samani (1985), Benavides-Lopez, original Penman, Linacre, Blaney-Morin, Romanenko, Hargreaves (1974), McCloud, Camargo, Hamon, Kharrufa, McGuiness-Bordne, and Blaney-Criddle were compared to that standard method recommended by FAO. The estimations were correlated by linear regression and assessed by using the Person’s correlation coefficient (r), concordance index (d), and performance index (c) using a set of meteorological data of approximately 40 years. The methods modified Hargreaves, Stephens-Stewart, Abtew, global radiation, Ivanov, Lungeon, Hargreaves-Samani (1985), Benavides-Lopez, original Penman, and Linacre should be avoided, as they did not present excellent results. The methods McCloud, Camargo, Hamon, Kharrufa, McGuinness-Bordne, Blaney-Criddle, Hargreaves (1974), Romanenko, and Blaney-Morin were classified as very bad, not being recommended. In contrast, the methods temperature radiation, Hicks-Hess, Hargreaves-Samani (1982), Turc, Priestley-Taylor, Tenner-Pelton, Jensen-Haise, and Makkink presented excellent performance indices and can be applied in the study region.

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