scholarly journals The Impact of Gridded Weather Database on Soil Water Availability in Rice Crop Modeling

2021 ◽  
Author(s):  
Caio Teodoro Menezes ◽  
Derblai Casaroli ◽  
Alexandre Bryan Heinemann ◽  
Vinicius Cintra Moschetti ◽  
Rafael Battisti
Keyword(s):  
Sandy Soil ◽  
Upland Rice ◽  
Crop Modeling ◽  
Time Step ◽  
R And D ◽  
Daily Time Step ◽  
D Values ◽  
Attainable Yield ◽  
The Impact ◽  
Daily Time

Abstract In recent years, there has been an increase in studies suggesting that gridded weather database (GWD) is a suitable source for simulating crop yield. Brazil has low geospatial coverage by measured weather database (MWD). Based on that, this study aimed to compare two different GWD sources, Daily Gridded (DG) and NASA/POWER (NP), on the simulated yield of upland rice (UR) against the MWD input. The GWD and MWD were obtained for seven locations across UR Brazilian region, considering a period ranging from 1984 to 2016. GWD and MWD were used to estimate rice potential (Yp) and attainable yield (Ya), in clay soil and sandy soil, using ORYZA (v3) model. DG had the best performance for all variables. GWD-based yields had a reasonable performance. However, DG had a slightly better performance than NP in all conditions, DG-based yields showed RMSE values of 0.57, 0.71 and 0.52 for Yp and Ya in clay and sandy soil, whereas NP showed RMSE values of 0.86, 0.91 and 0.64. DG also showed higher R² and d values for yields assessed. Both GWD overestimated Ya, these overestimations in DG-based yield were 3.54, 9.61, and 21.35% for Yp and Ya in clay and sandy soil respectively, in NP-based yield were 13.67, 18.45, 29.11%, showing that for both GWD-based yield increased as the soil type texture as well as water storage decreased. As a consequence, we do not recommend the use of precipitation data in daily time-step crop modeling.

Using a high-resolution regional climate model large ensemble to simulate the impact of extreme precipitation on flooding over small to medium-size catchments

2021 ◽  
Author(s):  
Mina Faghih ◽  
François Brissette ◽  
Parham Sabeti ◽  
Mostafa Tarek
Keyword(s):  
Return Period ◽  
Extreme Precipitation ◽  
Climate Model ◽  
Large Ensemble ◽  
Catchment Scale ◽  
Time Step ◽  
Daily Time Step ◽  
The Impact ◽  
Small Catchments ◽  
Daily Time

<p>Recent studies show that the frequency and intensity of extreme precipitation will increase under a warmer climate. It is expected that extreme convective precipitation will scale at a larger than Clausius–Clapeyron rate and especially so for short-duration rainfall. This has implication on flooding risk, and especially so on small catchments (<500 km<sup>2</sup>) which have a quick response time and are therefore particularly vulnerable to short duration rainfall. The impact of the amplification of extreme precipitation as a function of catchment scale has not been widely studied because most of the climate change impact studies have been conducted at the daily time step or higher. This is because until recently the vast majority of climate model outputs have only been available at the daily time step.</p><p>This study has looked at the amplification of sub-daily, daily, and multiday extreme precipitation and flooding and its dependency on catchment scale. This work uses outputs from the Climex large-ensemble to study the amplification of extreme streamflow with return period from 2 to 300 years and durations from 1 to 24 hours over 133 North-American catchments. Using a large ensemble allows for the accurate empirical computation of extreme events with very large return periods.  Results indicate that future extreme streamflow relative increases are largest for smaller catchments, longer return period, and shorter rainfall durations. Small catchments are therefore more vulnerable to future extreme rainfall than their larger counterparts.</p>

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.

Simulation of the water and isotopic balance of a closed tropical lake at a daily time step (Lake Ihotry, South-West of Madagascar)

2006 ◽  
Vol 88 (1-3) ◽  
pp. 153-156 ◽  
Author(s):  
Christine Vallet-Coulomb ◽  
Françoise Gasse ◽  
Laurent Robison ◽  
Luc Ferry
Keyword(s):  
Tropical Lake ◽  
Time Step ◽  
South West ◽  
Daily Time Step ◽  
Daily Time

Population dynamics of rainbow smelt (Osmerus mordax) in Lakes Ontario and Erie: a modeling analysis of cannibalism effects

2000 ◽  
Vol 57 (8) ◽  
pp. 1594-1606 ◽  
Author(s):  
Brian F Lantry ◽  
Donald J Stewart
Keyword(s):  
Population Dynamics ◽  
Lake Erie ◽  
Lake Ontario ◽  
Osmerus Mordax ◽  
Time Step ◽  
Rainbow Smelt ◽  
Modeling Analysis ◽  
Daily Time Step ◽  
Annual Time ◽  
Daily Time

We used a stochastic stage-based matrix model (annual time step) and a bioenergetics model (daily time step) to simulate population dynamics, production, consumption, and conversion efficiency for rainbow smelt (Osmerus mordax) populations in Lakes Ontario and Erie. Cannibalism on young-of the-year (YOY) smelt by yearlings was the only scenario that reproduced alternate-year recruitment cycles observed in Lakes Ontario and Erie. Assuming constant survivorship and 5% variation in cannibalism, less than one YOY consumed per yearling smelt per year in both lakes could produce fluctuations greater than those observed. We found that at estimated daily mortality rates and during the pelagic phase of larvae only, 2% of the yearling smelt in Lake Erie and 5.1% in Lake Ontario need to consume one YOY per day to induce the observed abundance fluctuations. Bioenergetics simulations of alternating recruitment produced fluctuations in simulated values for annual gross production of approximately 6-7 and 31-59% for the Lake Ontario and Lake Erie smelt populations, respectively.

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