scholarly journals Using remotely sensed solar radiation data for reference evapotranspiration estimation at a daily time step

2008 ◽  
Vol 148 (4) ◽  
pp. 619-630 ◽  
Author(s):  
B. Bois ◽  
P. Pieri ◽  
C. Van Leeuwen ◽  
L. Wald ◽  
F. Huard ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Reference Evapotranspiration ◽  
Remotely Sensed ◽  
Time Step ◽  
Radiation Data ◽  
Daily Time Step ◽  
Evapotranspiration Estimation ◽  
Daily Time

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 Performance of different methods for reference evapotranspiration estimation in Jaíba, Brazil

2018 ◽  
Vol 22 (2) ◽  
pp. 83-89 ◽  
Author(s):  
Gustavo H. da Silva ◽  
Santos H. B. Dias ◽  
Lucas B. Ferreira ◽  
Jannaylton É. O. Santos ◽  
Fernando F. da Cunha
Keyword(s):  
Wind Speed ◽  
Solar Radiation ◽  
Standard Method ◽  
Reference Evapotranspiration ◽  
Meteorological Data ◽  
Air Humidity ◽  
Method Performance ◽  
Relative Air Humidity ◽  
Evapotranspiration Estimation ◽  
Missing Variables

ABSTRACT FAO Penman-Monteith (FO-PM) is considered the standard method for the estimation of reference evapotranspiration (ET0) but requires various meteorological data, which are often not available. The objective of this work was to evaluate the performance of the FAO-PM method with limited meteorological data and other methods as alternatives to estimate ET0 in Jaíba-MG. The study used daily meteorological data from 2007 to 2016 of the National Institute of Meteorology’s station. Daily ET0 values were randomized, and 70% of these were used to determine the calibration parameters of the ET0 for the equations of each method under study. The remaining data were used to test the calibration against the standard method. Performance evaluation was based on Willmott’s index of agreement, confidence coefficient and root-mean-square error. When one meteorological variable was missing, either solar radiation, relative air humidity or wind speed, or in the simultaneous absence of wind speed and relative air humidity, the FAO-PM method showed the best performances and, therefore, was recommended for Jaíba. The FAO-PM method with two missing variables, one of them being solar radiation, showed intermediate performance. Methods that used only air temperature data are not recommended for the region.

Alternative climate data sources for distributed hydrological modelling on a daily time step

2010 ◽  
Vol 25 (10) ◽  
pp. 1542-1557 ◽  
Author(s):  
Ashraf El-Sadek ◽  
Max Bleiweiss ◽  
Manoj Shukla ◽  
Steve Guldan ◽  
Alexander Fernald
Keyword(s):  
Hydrological Modelling ◽  
Data Sources ◽  
Climate Data ◽  
Time Step ◽  
Daily Time Step ◽  
Distributed Hydrological Modelling ◽  
Daily Time

A model of expansion and senescence of individual leaves of field-grown maize (Zea mays L.)

1994 ◽  
Vol 74 (1) ◽  
pp. 37-42 ◽  
Author(s):  
D. W. Stewart ◽  
L M. Dwyer
Keyword(s):  
Leaf Area ◽  
Zea Mays L ◽  
Growth Models ◽  
Time Step ◽  
Leaf Area Expansion ◽  
Daily Time Step ◽  
Area Expansion ◽  
Area Development ◽  
Leaf Area Development ◽  
Daily Time

Estimation of leaf area is a major component of plant growth models. In this study, a model was developed to calculate field-grown maize leaf area expansion and senescence on an individual leaf basis. The model began with an equation, based on cumulative growing degree-days from emergence, to initiate leaf area development. The model required daily values of maximum and minimum air temperature, solar radiation and precipitation, had essentially a daily time step with day and night modes, and could be run on commonly accessible computers (micros to mainframes). The objective of the development of the model was to assist plant breeders in optimizing leaf number and shape for adaptation to specific environments. Key words: Leaf area and number, temperature, phenological development

scholarly journals Evaluation of a MODIS-Based Potential Evapotranspiration Product at the Point Scale

2008 ◽  
Vol 9 (3) ◽  
pp. 444-460 ◽  
Author(s):  
Jongyoun Kim ◽  
Terri S. Hogue
Keyword(s):  
Potential Evapotranspiration ◽  
Simple Algorithm ◽  
Sensor Data ◽  
Net Radiation ◽  
Point Scale ◽  
Time Step ◽  
Satellite Platform ◽  
Daily Time Step ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Daily Time

Abstract This paper outlines the development of a continuous, daily time series of potential evapotranspiration (PET) using Moderate Resolution Imaging Spectroradiometer (MODIS) sensor data from the Terra satellite platform. The approach is based on the Priestley–Taylor equation, incorporating a daily net radiation model during cloudless days. A simple algorithm using “theoretical clear-sky” net radiation (incorporating daily cloud fraction and cloud optical thickness) and PET is then used to estimate net radiation and PET under cloudy conditions. The method requires minimal ground-based observations for initial calibration of regional radiation algorithm coefficients. Point-scale comparisons are undertaken at four flux-tower sites in North America covering a range of hydroclimatic conditions and biomes. Preliminary results at the daily time step for a 4-yr period (2001–04) show good correlation (R2 = 0.89) and low bias (0.34 mm day−1) for three of the more humid sites. Results are further improved when aggregated to the monthly time scale (R2 = 0.95, bias = 0.31 mm day−1). Performance at the semiarid site is less satisfactory (R2 = 0.95, bias = 2.05 mm day−1 at the daily time step). In general, the MODIS-based daily PET estimates derived in this study are promising and show the potential for use in theoretical and operational water resource studies in both gauged and ungauged basins.

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