scholarly journals Ajuste de un modelo para estimar el contenido de humedad del suelo utilizando TVDI en el Estado de Sinaloa, México

UGCiencia ◽  
2016 ◽  
Vol 22 (1) ◽  
pp. 25
Author(s):  
Miguel Armando Lopez Beltran ◽  
Miguel López Meza ◽  
Martín Abraham Ramirez Tirado
Keyword(s):  
Dryness Index

<p>Para la estimación del contenido de humedad en el suelo, existen diversos métodos entre los cuales son directos e indirectos. En percepción remota o teledetección, se puede utilizar el TVDI (Temperature-Vegetation Dryness Index), que utiliza de parámetros de entrada las temperaturas superficiales terrestres e índices de vegetación. La propuesta de este trabajo, es presentar una manera rápida de reajustar aquellos valores donde los cuerpos de agua presentan algún grado de sequedad en el suelo para toda un área de estudio. Se seleccionaron 4 años (20003, 2006, 2009 y 2012), se estimó el TVDI con insumos de productos MODIS. Se propuso un valor de ajuste basado en la diferencia de la media y desviación estándar de los cuerpos de agua, se aplica este valor en el producto generado dando como resultado que los cuerpos de agua presentan ahora si una saturación de humedad en sus suelos. Los valores de ajustes son diferentes para cada año de estudio. El contenido de humedad es consistente a la variabilidad esperada acorde a los diferentes usos de suelo y vegetación. Los resultados están acorde a los reportes de sequía reportadas para el Estado de Sinaloa.</p><p> </p>

Effects of climate change and human interactions on water balance dynamics in the River Vistula basin

2021 ◽  
Author(s):  
Renata Romanowicz ◽  
Emilia Karamuz ◽  
Jaroslaw Napiorkowski ◽  
Tesfaye Senbeta
Keyword(s):  
Water Balance ◽  
Groundwater Level ◽  
Structural Model ◽  
Human Impacts ◽  
Management Scenarios ◽  
Annual Water Balance ◽  
Catchment Size ◽  
Dryness Index ◽  
Water Balance Models ◽  
Annual Water

&lt;div&gt; &lt;p&gt;Water balance modelling is often applied in studies of climate and human impacts on water resources. Annual water balance is usually derived based on precipitation, discharge and temperature observations under an assumption of negligible changes in annual water storage in a catchment. However, that assumption might be violated during very dry or very wet years. In this study we apply groundwater level measurements to improve water balance modelling in nine sub-catchments of the River Vistula basin starting from the river sources downstream. Annual and inter-annual water balance is studied using a Budyko framework to assess actual evapotranspiration and total water supply. We apply the concept of effective precipitation to account for possible losses due to water interception by vegetation. Generalised Likelihood Uncertainty Estimation GLUE is used to account for parameter and structural model uncertainty, together with the application of eight Budyko-type equations. Seasonal water balance models show large errors for winter seasons while summer and annual water balance models follow the Budyko framework. The dryness index is much smaller in winter than in summer for all sub-catchments. The spatial variability of water balance modelling errors indicate an increasing uncertainty of model predictions with an increase in catchment size. The results show that the added information on storage changes in the catchments provided by groundwater level observations largely improves model accuracy. The results also indicate the need to model groundwater level variability depending on external factors such as precipitation and evapotranspiration and human interventions. The modelling tools developed will be used to assess future water balance in the River Vistula basin under different water management scenarios and climate variability.&lt;/p&gt; &lt;/div&gt;

scholarly journals Evaluation of an instantaneous dryness index-based calibration-free continuous hydrological model in India

2019 ◽  
Vol 50 (3) ◽  
pp. 915-924 ◽  
Author(s):  
Swagat Patnaik ◽  
Vimal Chandra Sharma ◽  
Basudev Biswal
Keyword(s):  
Coefficient Of Determination ◽  
Ungauged Catchments ◽  
Peninsular India ◽  
Continuous Models ◽  
Free Model ◽  
The Usa ◽  
Dryness Index ◽  
Calibration Free ◽  
Definition Of ◽  
Box Cox Transformation

Abstract Traditional continuous hydrological models have a large number of free parameters whose values need to be determined through calibration, and thus their applicability is limited to gauged basins. For prediction in ungauged catchments, hydrologists generally follow regionalization methods to develop region-specific calibration-free continuous models. An alternative attempt was made recently to develop a calibration-free model by proposing an empirically derived universal ‘decay function’ that enables definition of instantaneous dryness index as a function of antecedent rainfall and solar energy. The model was earlier tested in the USA, and its performance was found to be comparable to that shown by regionalization-based models. Here, we test the instantaneous dryness index-based calibration-free model considering data from 108 Indian catchments. The medians of coefficient of determination (R2), Nash–Sutcliffe efficiency (NSE) and Kling–Gupta efficiency (KGE) values for the study catchments, respectively, are 0.50, 0.38 and 0.40. Furthermore, the model's performance significantly improved upon Box–Cox transformation (RBC2, NSEBC and KGEBC, respectively, are 0.70, 0.52 and 0.57), suggesting that the model predicts discharge quite well except during flood periods. Overall, our results suggest the model can be used as an alternative platform for predicting discharge in ungauged catchments in the USA and peninsular India, if not in every part of the world.

Prescribed Burning of Thinning Slash in Regrowth Stands of Karri (Eucalyptus diversicolor) .2. Nitrogen Budgets in Pre- and Post-Burn Fuel

1997 ◽  
Vol 7 (1) ◽  
pp. 41 ◽  
Author(s):  
AM O'Connell ◽  
WL McCaw
Keyword(s):  
Prescribed Burning ◽  
Fire Hazard ◽  
Weather Conditions ◽  
Moderate Intensity ◽  
Litter Layer ◽  
Nitrogen Budgets ◽  
Dryness Index ◽  
Soil Dryness ◽  
Fuel Components ◽  
Eucalyptus Diversicolor

Changes in nitrogen content of fuel were investigated following eight low to moderate intensity experimental fires conducted under a range of fire weather conditions in a recently thinned 22-year-old regrowth stand of karri (Eucalyptus diversicolor F. Muell) in Western Australia. The average amount of dead fuel < 100 mm in diameter present before burning was 76 t/ha (range 50 to 107 t/ha). The amount of live fuel was small, with a mean of 4 t/ha. Forest floor litter, consisting of fresh and partly decomposed dead leaves and fine twigs (< 6 mm diameter) contributed about 30% of total fuel weight, and wood fractions > 6 mm in diameter contributed about 60%. Remaining fuel was made up of small twigs, bark and leaves added from the thinning operation. Distribution of nitrogen in fuel fractions differed markedly from distribution of fuel weights with more than 60% of fuel-nitrogen in the litter and only about 25% of fuel-nitrogen in wood greater than 6 mm diameter. Following fire, the average amounts of nitrogen in all fuel fractions was reduced. The majority of nitrogen in wood fractions and in bark and leaves was volatilized during the fires (range 55% to 99%), while on average only about 38% of the nitrogen in litter was volatilized. The amount of nitrogen lost from dead fuel differed between the experimental fires (range 50 to 180 kg/ha) and was significantly related to the total amount of fuel consumed (r2 = 0.92). Fuel consumption and nitrogen volatilization increased as the Soil Dryness Index increased and as litter moisture decreased. Nitrogen losses due to burning were small relative to total stores of nitrogen in soil (about 6000 kg/ha) but for the most intense fires were significant in relation to amounts in growing vegetation and surface soil. Burning when moisture content of the litter profile exceeds 90% will reduce combustion of the litter layer. Burning under these conditions allows effective reduction in the flash fuel components located in the upper parts of the fuel bed while retaining much of the nutrient-rich lower strata of fuel. Burns of this type provide effective fire hazard reduction while favouring conservation of nitrogen stored in the litter layer.

scholarly journals USO DO ÍNDICE TVDI E MODELO HAND PARA CARACTERIZAÇÃO DE CONDIÇÃO HÍDRICA

Irriga ◽  
2017 ◽  
Vol 1 (1) ◽  
pp. 76-84 ◽  
Author(s):  
Lucimara Wolfarth Schirmbeck ◽  
Denise Cybis Fontana ◽  
Juliano Schirmbeck ◽  
Vagner Paz Mengue
Keyword(s):  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Rio Grande ◽  
United States Geological Survey ◽  
Landsat 8 ◽  
Rio Grande Do Sul ◽  
Landsat 8 Oli ◽  
Porto Alegre ◽  
Soybean Crop ◽  
Dryness Index

USO DO ÍNDICE TVDI E MODELO HAND PARA CARACTERIZAÇÃO DE CONDIÇÃO HÍDRICA  LUCIMARA WOLFARTH SCHIRMBECK1; DENISE CYBIS FONTANA2; JULIANO SCHIRMBECK3 E VAGNER PAZ MENGUE4 1 Centro Estadual de Pesquisas em Sensoriamento Remoto e Meteorologia – Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, [email protected] Departamento de Plantas Forrageiras e Agrometeorologia – Faculdade de Agronomia –  Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, [email protected] Centro Estadual de Pesquisas em Sensoriamento Remoto e Meteorologia – Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, [email protected] Centro Estadual de Pesquisas em Sensoriamento Remoto e Meteorologia – Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, [email protected].  1 RESUMO O objetivo do trabalho foi avaliar a adequação do índice TVDI (Temperature Vegetation Dryness Index), obtido com sensores remotos orbitais, para caracterizar a condição hídrica de lavouras de soja no sul do Brasil. Para tanto, foram utilizadas imagens do satélite Landsat 8-OLI, obtidas da base de dados da USGS (United States Geological Survey), de três datas ao longo do ciclo da cultura da soja (5 de dezembro 2014 – implantação, 6 de janeiro 2015 - início de desenvolvimento e 7 de fevereiro de 2015 – pleno desenvolvimento vegetativo).  A área de cultivo de soja foi mapeada utilizando classificação digital (máxima verossimilhança) e validada com dados de campo. A área total mapeada foi estratificada em duas classes: áreas de várzea e áreas altas, através do uso do modelo HAND (Height Above the Nearest Drainage). Para tornar possível a comparação entre datas, o TVDI foi determinado usando um triângulo único para as três datas em conjunto, estabelecido a partir dos dados do NDVI (Normalized Difference vegetation Index) e da temperatura de superfície (TS), a qual foi estimada usando o algoritmo split-window. O TVDI permitiu diferenciar as condições hídricas na cultura da soja ao longo do ciclo e entre as classes de altitude; as áreas mais altas apresentaram maiores déficits quando comparadas às áreas de várzea. Foi possível ainda visualizar a migração dos pixels de soja dentro do triângulo evaporativo como consequência da fase de desenvolvimento da cultura e das condições hídricas. Palavras-chave: déficit hídrico, agricultura, Landsat 8-OLI.  SCHIRMBECK, L. W.; FONTANA, D. C.; SCHIRMBECK, J.; MENGUE, V.P. TVDI INDEX AND HAND MODEL FOR WATER CONDITION DESCRIPTION  2 ABSTRACT This work aims to evaluate the suitability of the Temperature Vegetation Dryness Index (TVDI), achieved through an orbital remote sensing system used to describe the condition of the water to be used on soybean crops in the South Region of Brazil. The Landsat 8-OLI satellite images were gathered from the USGS (United States Geological Survey) database of three different dates during the soybean crop cycle (December 5th, 2014 - implementation, January 6th, 2015 - beginning of growth and February 7th, 2015 - full vegetative growth). The soybean crop area was mapped using digital classification (maximum likelihood method) and validated with field data. The total mapped area was stratified into two classes: floodplain areas and high areas, using the HAND (Height Above the Nearest Drainage) model. To make the comparison between dates possible, TVDI was determined using a single triangle for all the three dates together, established using the Normalized Difference Vegetation Index (NDVI) and surface temperature (TS) data, which was estimated using Split-window algorithm. TVDI allowed us to differentiate the water conditions during the soybean crop cycle and between the two altitude classes; the higher areas presented larger deficits when compared to the floodplain areas. It was also possible to observe the migration of the soybean pixels within the evaporative triangle as a consequence of the crop’s development stage and the water conditions. Keywords: water deficit, agriculture, Landsat 8-OLI. 

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