ISSN e:2007-4026 / ISSN print: 2007-3925

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     Vol. 15, issue 2 July - December 2023  Creative Commons License

      
 

     Vol. 15, issue 2 July - December 2023  

 
  

  • Evaluation of the SPI with high-resolution datasets in historical and future climate in central Mexico

  • Evaluación del índice de precipitación estandarizado (SPI) con datos de alta resolución en clima histórico y futuro en el centro de México

Juan Alberto Velázquez-Zapata

Keywords: drought, standard precipitation index, CHIRPS, PERSIANN-CDR, climate change

10.5154/r.inagbi.2023.06.030

Received: 2023-05-30
Accepted: 2023-12-13
Available online: 2023-12-29
Pages:3-23

Introduction: Drought monitoring needs good quality meteorological data, but records frequently face problems. Therefore, satellite precipitation datasets are an alternative.
Objective: Evaluation of three high-resolution datasets (compared with observed precipitation) to capture wet and dry periods. In addition, the influence of the selection of the dataset to downscale future climate simulations is evaluated in the estimation of drought indicators.
Methodology: Precipitation products (NOAA, CHIRPS and PERSIANN-CDR) were compared with observations from seven meteorological stations (1983-2013). The 12-month standard precipitation index (SPI) was selected to evaluate drought conditions. Also, precipitation estimates from CanESM2 were downscaled and bias-corrected with each dataset.
Results: The annual precipitation cycle is well capture, but underestimation is noted. The datasets have a good correlation, but less variability. Regarding the SPI, results show good correlation, but extremely dry events are generally underestimated with CHIRPS and PERSIANN-CDR. The NOAA dataset performs better in terms of categorical scores, especially for wet events. Similar median values were found in the drought indicators in future; however, the datasets lead to less variability than observations, especially in the drought frequency indicator.
Study limitations: Limited number of good quality meteorological records.
Originality: Selected precipitation datasets are tested under different climatic conditions for the first time in Mexico. Also, the influence of the reference precipitation dataset for bias correction is evaluated on future drought projections.
Conclusions: Precipitation products should be tested before their use in monitoring droughts in the historical period, as well as in estimating droughts with future projections.

....

Introduction: Drought monitoring needs good quality meteorological data, but records frequently face problems. Therefore, satellite precipitation datasets are an alternative.
Objective: Evaluation of three high-resolution datasets (compared with observed precipitation) to capture wet and dry periods. In addition, the influence of the selection of the dataset to downscale future climate simulations is evaluated in the estimation of drought indicators.
Methodology: Precipitation products (NOAA, CHIRPS and PERSIANN-CDR) were compared with observations from seven meteorological stations (1983-2013). The 12-month standard precipitation index (SPI) was selected to evaluate drought conditions. Also, precipitation estimates from CanESM2 were downscaled and bias-corrected with each dataset.
Results: The annual precipitation cycle is well capture, but underestimation is noted. The datasets have a good correlation, but less variability. Regarding the SPI, results show good correlation, but extremely dry events are generally underestimated with CHIRPS and PERSIANN-CDR. The NOAA dataset performs better in terms of categorical scores, especially for wet events. Similar median values were found in the drought indicators in future; however, the datasets lead to less variability than observations, especially in the drought frequency indicator.
Study limitations: Limited number of good quality meteorological records.
Originality: Selected precipitation datasets are tested under different climatic conditions for the first time in Mexico. Also, the influence of the reference precipitation dataset for bias correction is evaluated on future drought projections.
Conclusions: Precipitation products should be tested before their use in monitoring droughts in the historical period, as well as in estimating droughts with future projections.

....
 

  • Hydraulic analysis of a long-throated flume for sediment-laden flow using CFD

  • Análisis hidráulico de una estructura aforadora de garganta larga para flujo con sedimentos utilizando CFD

Juan Gabriel Brigido-Morales; Mauricio Carrillo-García; Jorge Victor Prado-Hernández; Jorge Flores-Velázquez

Keywords: design, water measurement, supercritical flow, numerical analysis, sediment-laden flow

10.5154/r.inagbi.2022.11.090

Received: 2022-11-04
Accepted: 2023-12-13
Available online: 2024-03-04
Pages:3-22

Introduction: There are many flumes available, but few have been designed for flow measurement in
natural streams, where natural erosion leads to increased sediment levels, causing erroneous readings.
Objective: Analyzing the hydraulic behavior of a modified long-throated flume to determine the optimal location for taking readings in the presence of excessive sediment, using the programs HEC-RAS® v.5.0.7, Iber® v.2.5.2 and ANSYS® CFX® v.2020 R2.
Methodology: In this study, a long-throated flume was designed and analyzed for a maximum flow rate of 50 L∙s-1 using the WinFlume® v.1.0.6 program. Four structures were constructed, each equipped with a steeper slope of 5 %, 10 %, 20 %, and 30 %, and an additional four variants were implemented with a reduction in the hydraulic area at the throat inlet. Five measurement locations were chosen starting from the beginning of the steeper slope for a hydraulic analysis in one, two, and three dimensions.
Result: The optimal location for plotting flow (Q) vs. flow depth (h) curves is located at 2/5 parts at the start of the steeper slope, with a slope of 10 % and a coefficient of determination (R2) of 0.99986.
Limitations of the study: The geometric models of the proposed flume have only been analyzed numerically, so a second stage at the laboratory level must be carried out. Originality: There is a limited number of studies dedicated to the analysis of long-throated flumes operating under conditions with sediment-laden flows
Conclusions: A long-throated flume with a steeper slope proves to be a practical solution for decision-making concerning water management, aiming to enhance its efficiency.

....

Introduction: There are many flumes available, but few have been designed for flow measurement in
natural streams, where natural erosion leads to increased sediment levels, causing erroneous readings.
Objective: Analyzing the hydraulic behavior of a modified long-throated flume to determine the optimal location for taking readings in the presence of excessive sediment, using the programs HEC-RAS® v.5.0.7, Iber® v.2.5.2 and ANSYS® CFX® v.2020 R2.
Methodology: In this study, a long-throated flume was designed and analyzed for a maximum flow rate of 50 L∙s-1 using the WinFlume® v.1.0.6 program. Four structures were constructed, each equipped with a steeper slope of 5 %, 10 %, 20 %, and 30 %, and an additional four variants were implemented with a reduction in the hydraulic area at the throat inlet. Five measurement locations were chosen starting from the beginning of the steeper slope for a hydraulic analysis in one, two, and three dimensions.
Result: The optimal location for plotting flow (Q) vs. flow depth (h) curves is located at 2/5 parts at the start of the steeper slope, with a slope of 10 % and a coefficient of determination (R2) of 0.99986.
Limitations of the study: The geometric models of the proposed flume have only been analyzed numerically, so a second stage at the laboratory level must be carried out. Originality: There is a limited number of studies dedicated to the analysis of long-throated flumes operating under conditions with sediment-laden flows
Conclusions: A long-throated flume with a steeper slope proves to be a practical solution for decision-making concerning water management, aiming to enhance its efficiency.

....