scholarly journals PLUVIÔMETRO DE BAIXO CUSTO E A VARIAÇÃO DA CHUVA NO MUNICÍPIO DE BARRA DO GARÇAS – MT (OUTUBRO DE 2015 A ABRIL DE 2016)

2017 ◽  
Vol 3 (8) ◽  
pp. 107
Author(s):  
Romário Rosa de Sousa
Keyword(s):  
Low Cost ◽  
Rainfall Variability ◽  
Rain Gauge ◽  
Urban Environments ◽  
Data Interpolation ◽  
Rain Gauges ◽  
Rural And Urban ◽  
Electronic Spreadsheet ◽  
Map Data ◽  
Rainfall Map

LOW COST RAIN GAUGES AND RAINFALL VARIABILITY IN BARRA DO GARÇAS – MT (OCTOBER 2015 TO APRIL 2016)PLUVIÓMETRO DE BAJO COSTO Y LA VARIACIÓN DE LA LLUVIA EN EL MUNICIPIO DE BARRA DO GARÇAS – MT (OCTUBRE DE 2015 A ABRIL 2016)Este trabalho teve como objetivo principal confeccionar e distribuir vinte pluviômetros de baixo custo de PVC, dentro do município de Barra do Garças-MT, onde posteriormente a partir dos dados coletados, gerou-se um mapa pluviométrico da irregularidade da chuva. Os trabalhos metodológicos foram desenvolvidos em onze etapas distintas. Após toda a fase de aquisição dos materiais de baixo custo, na sequência realizou-se os seguintes procedimentos: confecção dos pluviômetros, aferição, instalação, treinamento dos produtores rurais, coleta de dados a campo, organização dos dados em planilha eletrônica com geração de relatório de tabela dinâmica, realização do processo de interpolação dos dados, geração do mapa pluviométrico, ajustes e finalização do mapa gerado, análise e discussão dos dados. É importante ressaltar que o processo de interpolação dos dados foi realizado no software ArcGis, 10.1. Ressalta-se que o processo de construção do pluviômetro de baixo custo, demonstrou que foi de grande ajuda, no sentido de baixar custos com um instrumento de grande importância para o meio rural e urbano. Também ficou comprovado que o pluviômetro de baixo custo, é um aparelho de credibilidade e confiabilidade nos registros dos dados pluviométricos. Quanto a distribuição pluviométrica da chuva no município de Barra do Garças-MT, foi bem diversificada e irregular para o período estudado, onde averiguou-se que o maior acumulo pluviométrico foi registrado no extremo sul do município com 986,1mm de chuva. E encontra partida um núcleo seco com um baixo volume de precipitação foi confirmado na porção leste com 146,2 mm de chuva.Palavras-chave: Pluviômetros; Chuva; PVC; Baixo Custo.ABSTRACTThis study aims to design, assemble and distribute twenty low cost PVC rain gauges in Barra do Garças-MT, where afterwards a rainfall map was generated from the collected data. The methodological works were developed in eleven distinct stages. Following the entire acquisition phase of the low cost materials, the following procedures were carried out: preparation of the rain gauges, gauging, installation, training of rural producers, data collection in the field, data organization in electronic spreadsheet making a dynamic table report, data interpolation, creating a rainfall map, adjustment and finalization of the created map, data analysis and discussion. It is important to note the data interpolation process was performed in ArcGis software, 10.1. It should be noted that the process of construction of the low cost rain gauge showed that it was of great help in order to reduce costs with an instrument of great importance for the rural and urban environments. It has also been proven that the low cost rain gauge is an apparatus of credibility and reliability in rainfall records. As for the rainfall distribution in Barra do Garças-MT, it was well diversified and irregular for the period studied, where it was verified that the highest rainfall accumulation was recorded in the southern end of the municipality with 986.1mm of rain. However, finding a dry core with a low volume of precipitation was confirmed in the eastern portion with 146.2mm of rain.Keywords: Rain Gauges; Rain; PVC; Low Cost.RESUMENEste trabajo tuvo como objetivo principal elaborar, montar y distribuir veinte pluviómetros de bajo costo de PVC, dentro del municipio de Barra do Garças-MT, posteriormente, a partir de los datos colectados, se originó un mapa pluviométrico de la irregularidad de la lluvia. Los trabajos metodológicos fueron desarrollados en once etapas distintas. Después de toda la fase de adquisición de los materiales de bajo costo, en seguida se realizaron los siguientes procedimientos: confección de los pluviómetros, calibración, instalación, entrenamiento de los productores rurales, colecta de datos a campo, organización de los datos en planilla electrónica con elaboración de un informe de tabla dinámica, realización del proceso de interpolación de los datos, producción del mapa pluviométrico, ajustes y finalización del mapa generado, análisis y discusión de los datos. Es importante realzar que el proceso de interpolación de los datos fueron realizados en el software ArcGis, 10.1. Se resalta que el proceso de construcción del pluviómetro de bajo costo, demostró que fue de gran ayuda, en el sentido de bajar costos con un instrumento de gran importancia para el medio rural y urbano. También quedó demostrado que el pluviómetro de bajo costo, es un aparato de credibilidad y confiabilidad en los registros de los datos pluviométricos. Cuanto a la distribución pluviométrica en el municipio de Barra do Garças-MT, fue bien diversificada e irregular para el periodo estudiado, donde se comprobó que el mayor acúmulo pluviométrico fue registrado en el extremo Sur del municipio con 986,1mm de lluvia. En contra partida un núcleo seco con un bajo volumen de precipitación fue confirmado en la región Este con 146,2 mm de lluvia.Palabras-clave: Pluviómetros; Lluvia; PVC; Bajo Costo.

scholarly journals Soil and nutrient losses in erosion gullies at different degrees of restoration

2010 ◽  
Vol 34 (3) ◽  
pp. 945-954 ◽  
Author(s):  
Roriz Luciano Machado ◽  
Alexander Silva de Resende ◽  
Eduardo Francia Carneiro Campello ◽  
José Arimathéa Oliveira ◽  
Avílio Antônio Franco
Keyword(s):  
Low Cost ◽  
Soil Classification ◽  
Urban Environments ◽  
Nutrient Loss ◽  
Data Sets ◽  
Nutrient Losses ◽  
Sediment Grain Size ◽  
Rural And Urban ◽  
Soil Sediment

The most advanced stage of water erosion, the gully, represents severe problems in different contexts, both in rural and urban environments. In the search for a stabilization of the process in a viable manner it is of utmost importance to assess the efficiency of evaluation methodologies. For this purpose, the efficiency of low-cost conservation practices were tested for the reduction of soil and nutrient losses caused by erosion from gullies in Pinheiral, state of Rio de Janeiro. The following areas were studied: gully recovered by means of physical and biological strategies; gullies in recovering stage, by means of physical strategies only, and gullies under no restoration treatment. During the summer of 2005/2006, the following data sets were collected for this study: soil classification of each of the eroded gully areas; planimetric and altimetric survey; determination of rain erosivity indexes; determination of amount of soil sediment; sediment grain size characteristics; natural amounts of nutrients Ca, Mg, K and P, as well as total C and N concentrations. The results for the three first measurements were 52.5, 20.5, and 29.0 Mg in the sediments from the gully without intervention, and of 1.0, 1.7 and 1.8 Mg from the gully with physical interventions, indicating an average reduction of 95 %. The fully recovered gully produced no sediment during the period. The data of total nutrient loss from the three gullies under investigation showed reductions of 98 % for the recovering gully, and 99 % for the fully recovered one. As for the loss of nutrients, the data indicate a nutrient loss of 1,811 kg from for the non-treated gully. The use of physical and biological interventions made it possible to reduce overall nutrient loss by more than 96 %, over the entire rainy season, as compared to the non-treated gully. Results show that the methods used were effective in reducing soil and nutrient losses from gullies.

scholarly journals Performance evaluation of the novel portable PIMA point-of-care CD4 analyzer in comparison with conventional flow cytometer instruments in Cameroon

2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Bertrand Sagnia ◽  
Rachel Kamgaing ◽  
Charles Kouanfack ◽  
Georgette Kamdem ◽  
Samuel Sosso ◽  
...  
Keyword(s):  
Health Care ◽  
T Lymphocytes ◽  
T Lymphocyte ◽  
Point Of Care ◽  
Low Cost ◽  
Urban Environments ◽  
Resource Constrained ◽  
Becton Dickinson ◽  
Inform Consent ◽  
Rural And Urban

Abstract Background Absolute CD4+ T-lymphocyte counts are used in the initiation and monitoring of antiretroviral therapy in HIV-infected patients: with the increase number of HIV infected patient and the reduce number of heath care system in rural zones, HIV monitoring in resource-constrained settings demands affordable and reliable CD4+ T lymphocytes enumeration methods. We evaluated a simple PIMA POC which is a dedicated system for enumeration that uses immunomagnetic and immunofluorescent technologies. The instrument was designed to be a low-cost, yet reliable and robust one. In this study, we assessed the correlation between most representative flow cytometry instruments present in Cameroon instead of CyFlow from PARTEC, FACSCount, and FACSCalibur both from Becton Dickinson. Methods CD4 surface markers on lymphocytes was measured on samples collected in EDTA tubes from 268 patients aged from 1 to 65 years old in three different health care structures. HIV infected patients are coming from CIRCB, Day Hospital of Hopital Central de Yaounde (HCY) and Hopital General de Yaounde (HGY). After inform consent, samples were collected and 101 samples were tested with the FACSCalibur, 60 samples were tested with the CyFlow and 107 samples were tested with the FACSCount flow cytometers. All these samples were tested by different technician with PIMA POC present in all these health care structures and the correlation and agreement were analyzed using linear regression and Bland–Altman analysis. Results The PIMA POC system has excellent precision, accuracy and linearity for CD4+ T lymphocytes enumeration. Good correlations were obtained between the PIMA POC system and other single platform methods. Bland–Altman plots showed interchangeability between the three machines. Absolute CD4+ T-lymphocyte values obtained from the PIMA system correlated well with Cyflow, FACSCount, and FACSCalibur method (r2 varies from 0.88 to 0.968, P < 0.0001). The comparison between values obtained from PIMA with CYFLOW, FACSCount, and FACSCalibur give P = 0.17, P = 0.5 and P = 0.6 respectively meaning that there is not significant differences between values obtained with PIMA and other flow machines. Conclusion This POC PIMA system is a simple and reliable system for enumeration of absolute CD4+ T-lymphocytes. Having one PIMA system easy to use, should reduce the cost and thus increase access to CD4 testing for HIV infected patients in resource-constrained countries. POC CD4 may also alleviate testing burdens at traditional central CD4 laboratories, hence improving test access in both rural and urban environments. This will reduce also the loss of follow up.

scholarly journals Radar subpixel-scale rainfall variability and uncertainty: lessons learned from observations of a dense rain-gauge network

2013 ◽  
Vol 17 (6) ◽  
pp. 2195-2208 ◽  
Author(s):  
N. Peleg ◽  
M. Ben-Asher ◽  
E. Morin
Keyword(s):  
Temporal Variability ◽  
Rainfall Variability ◽  
Rain Gauge ◽  
Small Scale ◽  
Spatial And Temporal Variability ◽  
Radar Rainfall ◽  
Rain Gauges ◽  
Daily Scale ◽  
Rain Gauge Network ◽  
Hydrological Applications

Abstract. Runoff and flash flood generation are very sensitive to rainfall's spatial and temporal variability. The increasing use of radar and satellite data in hydrological applications, due to the sparse distribution of rain gauges over most catchments worldwide, requires furthering our knowledge of the uncertainties of these data. In 2011, a new super-dense network of rain gauges containing 14 stations, each with two side-by-side gauges, was installed within a 4 km2 study area near Kibbutz Galed in northern Israel. This network was established for a detailed exploration of the uncertainties and errors regarding rainfall variability within a common pixel size of data obtained from remote sensing systems for timescales of 1 min to daily. In this paper, we present the analysis of the first year's record collected from this network and from the Shacham weather radar, located 63 km from the study area. The gauge–rainfall spatial correlation and uncertainty were examined along with the estimated radar error. The nugget parameter of the inter-gauge rainfall correlations was high (0.92 on the 1 min scale) and increased as the timescale increased. The variance reduction factor (VRF), representing the uncertainty from averaging a number of rain stations per pixel, ranged from 1.6% for the 1 min timescale to 0.07% for the daily scale. It was also found that at least three rain stations are needed to adequately represent the rainfall (VRF < 5%) on a typical radar pixel scale. The difference between radar and rain gauge rainfall was mainly attributed to radar estimation errors, while the gauge sampling error contributed up to 20% to the total difference. The ratio of radar rainfall to gauge-areal-averaged rainfall, expressed by the error distribution scatter parameter, decreased from 5.27 dB for 3 min timescale to 3.21 dB for the daily scale. The analysis of the radar errors and uncertainties suggest that a temporal scale of at least 10 min should be used for hydrological applications of the radar data. Rainfall measurements collected with this dense rain gauge network will be used for further examination of small-scale rainfall's spatial and temporal variability in the coming years.

scholarly journals Performance Evaluation of the Novel Portable PIMA Point-Of-Care CD4 Analyzer in Comparison with Conventional Flow Cytometer Instruments in Cameroon

2020 ◽  
Author(s):  
Bertrand Sagnia ◽  
Rachel Kamgaing ◽  
Charles Kouanfack ◽  
Georgette Kamdem ◽  
Samuel Sosso ◽  
...  
Keyword(s):  
Health Care ◽  
T Lymphocytes ◽  
T Lymphocyte ◽  
Point Of Care ◽  
Low Cost ◽  
Urban Environments ◽  
Resource Constrained ◽  
Becton Dickinson ◽  
Inform Consent ◽  
Rural And Urban

Abstract Background: Absolute CD4 + T-lymphocyte counts are used in the initiation and monitoring of antiretroviral therapy in HIV-infected patients: with the increase number of HIV infected patient and the reduce number of heath care system in rural zones, HIV monitoring in resource-constrained settings demands affordable and reliable CD4 + T lymphocytes enumeration methods. We evaluated a simple PIMA POC which is a dedicated system for enumeration that uses immunomagnetic and immunofluorescent technologies. The instrument was designed to be a low-cost, yet reliable and robust one. In this study, we assessed the correlation between most representative flow cytometry instruments present in Cameroon instead of CyFlow from PARTEC, FACSCount, and FACSCalibur both from Becton DickinsonMethods: CD4 surface markers on lymphocytes was measured on samples collected in EDTA tubes from 268 patients aged from 1 to 65 years old in three different health care structures. HIV infected patients are coming from CIRCB, Day Hospital of Hopital Central de Yaounde (HCY) and Hopital General de Yaounde (HGY). After inform consent, samples were collected and 101 samples were tested with the FACSCalibur, 60 samples were tested with the CyFlow and 107 samples were tested with the FACSCount flow cytometers. All these samples were tested by different technician with PIMA POC present in all these health care structures and the correlation and agreement were analyzed using linear regression and Bland–Altman analysis.Results: The PIMA POC system has excellent precision, accuracy and linearity for CD4 + T lymphocytes enumeration. Good correlations were obtained between the PIMA POC system and other single platform methods. Bland–Altman plots showed interchangeability between the three machines. Absolute CD4 + T-lymphocyte values obtained from the PIMA system correlated well with Cyflow, FACSCount, and FACSCalibur method (r2 varies from 0.88 to 0.968, P < 0.0001). The comparison between values obtained from PIMA with CYFLOW, FACSCount, and FACSCalibur give P = 0.17, P = 0.5 and P = 0.6 respectively meaning that there is not significant differences between values obtained with PIMA and other flow machines.Conclusion: This POC PIMA system is a simple and reliable system for enumeration of absolute CD4 + T-lymphocytes. Having one PIMA system easy to use, should reduce the cost and thus increase access to CD4 testing for HIV infected patients in resource-constrained countries. POC CD4 may also alleviate testing burdens at traditional central CD4 laboratories, hence improving test access in both rural and urban environments. This will reduce also the loss of follow up

scholarly journals On the value of high density rain gauge observations for small Alpine headwater catchments

2020 ◽  
Author(s):  
Anthony Michelon ◽  
Lionel Benoit ◽  
Harsh Beria ◽  
Natalie Ceperley ◽  
Bettina Schaefli
Keyword(s):  
Low Cost ◽  
Rain Gauge ◽  
High Density ◽  
Swiss Alps ◽  
Network Density ◽  
Runoff Coefficient ◽  
Hydrologic Response ◽  
Analysis Framework ◽  
Rain Gauges ◽  
Lag Times

Abstract. Spatial rainfall patterns exert a key control on the catchment scale hydrologic response. Despite recent advances in radar-based rainfall sensing, rainfall observation remains a challenge particularly in mountain environments. This paper analyzes the importance of high-density rainfall observations for a 13.4 km2 catchment located in the Swiss Alps where summer rainfall events were monitored during 3 months using a network of 12 low-cost, drop-counting rain gauges. We developed a data-based analysis framework to assess the importance of high-density rainfall observations to help constrain hydrologic processes. The framework is based on two steps, the identification of key hydro-meteorological metrics that explain the runoff coefficient and lag times (e.g. total event rainfall, center of mass of the precipitation field) and the identification of the optimal rain gauge network density to reliably reproduce the value of these metrics. The hydrological metrics are evaluated through correlation and regression analysis, resulting in the identification of three main drivers for the runoff coefficient and for runoff response lag times: the areal rainfall, the spatial asymmetry of the rainfall field and the antecedent rainfall over the three days preceding an event. The relationships between these measures and the optimal network density gives insights into the importance of reliably observing the localisation of incoming rainfall. Even at the small spatial scale of this case study, the results show that an accurate representation of the rainfall field, with at least two rain gauges, is of prime importance to understand the hydrologic response. The largely data-based analysis framework developed here is readily transferable to other settings. Given the low cost of the deployed rainfall sensor network, the approach has potential for future detailed studies in to-date sparsely observed catchments. Future work could in particular also refine the presented analysis by improving the design of the rain gauge deployment to ensure a good representation of geomorphological units and of the relative distances to the stream network.

scholarly journals Assessing a low-cost methane sensor quantification system for use in complex rural and urban environments

2018 ◽  
Vol 11 (6) ◽  
pp. 3569-3594 ◽  
Author(s):  
Ashley Collier-Oxandale ◽  
Joanna Gordon Casey ◽  
Ricardo Piedrahita ◽  
John Ortega ◽  
Hannah Halliday ◽  
...  
Keyword(s):  
Air Quality ◽  
Los Angeles ◽  
Oil And Gas ◽  
Spatial Scales ◽  
Low Cost ◽  
Urban Environments ◽  
Monitoring Networks ◽  
Linear Calibration ◽  
Spatial And Temporal Scales ◽  
Rural And Urban

Abstract. Low-cost sensors have the potential to facilitate the exploration of air quality issues on new temporal and spatial scales. Here we evaluate a low-cost sensor quantification system for methane through its use in two different deployments. The first was a 1-month deployment along the Colorado Front Range and included sites near active oil and gas operations in the Denver-Julesburg basin. The second deployment was in an urban Los Angeles neighborhood, subject to complex mixtures of air pollution sources including oil operations. Given its role as a potent greenhouse gas, new low-cost methods for detecting and monitoring methane may aid in protecting human and environmental health. In this paper, we assess a number of linear calibration models used to convert raw sensor signals into ppm concentration values. We also examine different choices that can be made during calibration and data processing and explore cross sensitivities that impact this sensor type. The results illustrate the accuracy of the Figaro TGS 2600 sensor when methane is quantified from raw signals using the techniques described. The results also demonstrate the value of these tools for examining air quality trends and events on small spatial and temporal scales as well as their ability to characterize an area – highlighting their potential to provide preliminary data that can inform more targeted measurements or supplement existing monitoring networks.

Combined rainfall estimates from personal weather station and commercial microwave link data in Germany

2021 ◽  
Author(s):  
Maximilian Graf ◽  
Abbas El Hachem ◽  
Micha Eisele ◽  
Jochen Seidel ◽  
Christian Chwala ◽  
...  
Keyword(s):  
Water Resource Management ◽  
Hydrological Cycle ◽  
Spatial Scales ◽  
Rainfall Variability ◽  
Rain Gauge ◽  
Data Sets ◽  
Rain Gauge Data ◽  
Rain Gauges ◽  
Gauge Data ◽  
Rainfall Estimates

&lt;p&gt;Rain gauges and weather radars are the default sources of rainfall information. Rainfall estimates from these sensors improve our understanding of the hydrological cycle and are vital for water-resource management, agriculture, urban planning, as well as for weather, climate, and hydrological modelling. Still, due to the high spatio-temporal variability of rainfall and the specific drawbacks of the individual rainfall sensors, the rainfall variability cannot be captured completely. In the last decade, the number and availability of opportunistic rainfall sensors increased rapidly. These sensors are initially not meant to measure rainfall for scientific or operational purposes, but, if processed carefully, can be used for these cases . Here we present an analysis of two years of data from two opportunistic rainfall sensors, namely personal weather stations (PWS) and commercial microwave links (CMLs). We evaluate the performance of rainfall maps derived from these sensors on different spatial and temporal scales in Germany.&lt;/p&gt;&lt;p&gt;The data from around 15000 PWS tipping bucket-style rain gauges from the Netatmo network were accessed via Netatmos API. The data from around 4000 CMLs, which can be used to derive rainfall estimates from the rain-induced attenuation of the CMLs&amp;#8217; signal, were obtained from Ericsson. As both, PWS and CML data, can suffer from various error sources e.g. from unfavourable positioning and poor maintenance of PWS and from non-rain induced attenuation of the CMLs signal, we used a strict filtering routine. A total of seven gridded rainfall products were derived from different combinations of PWS, CML, and rain gauge data from the German Weather Service (DWD) with a geostatistical interpolation approach. This approach incorporates the uncertainty of the opportunistic sensors and the path-averaging characteristic of the CML observations.&lt;/p&gt;&lt;p&gt;To evaluate the resulting rainfall maps, we used three rain gauge data sets with different temporal and spatial scales covering the whole of Germany, the state of Rhineland-Palatinate and the city of Reutlingen, respectively. For all three reference data sets, rainfall maps from opportunistic sensors provided good agreement, with best results being derived from the combinations with PWS. Rainfall maps including CML data had the lowest bias. In a comparison with gauge adjusted radar products from the DWD, the radar products yielded better results than the rainfall maps from opportunistic sensors for the country-wide comparison of daily rainfall sums, which was carried out using the DWD&amp;#8217;s independent network of manual rain gauges. But for the hourly references covering Rhineland-Palatinate and Reutlingen, the rainfall maps derived from opportunistic sensors outperformed the radar products. These results highlight the capabilities of opportunistic rainfall sensors which could be used in many hydrometeorological applications.&lt;/p&gt;

scholarly journals An entropy-based approach for the optimization of rain gauge network using satellite and ground-based data

2021 ◽  
Author(s):  
Claudia Bertini ◽  
Elena Ridolfi ◽  
Luiz Henrique Resende de Padua ◽  
Fabio Russo ◽  
Francesco Napolitano ◽  
...  
Keyword(s):  
Rainfall Variability ◽  
Rain Gauge ◽  
Ranking Algorithm ◽  
Monitoring Networks ◽  
Resources Management ◽  
Rain Gauges ◽  
New Sensors ◽  
Climate Prediction Center ◽  
Rain Gauge Network ◽  
Unsolved Issue

Abstract Accurate and precise rainfall records are crucial for hydrological applications and water resources management. The accuracy and continuity of ground-based time series rely on the density and distribution of rain gauges over territories. In the context of a decline of rain gauge distribution, how to optimize and design optimal networks is still an unsolved issue. In this work, we present a method to optimize a ground-based rainfall network using satellite-based observations, maximizing the information content of the network. We combine Climate Prediction Center MORPhing technique (CMORPH) observations at ungauged locations with an existing rain gauge network in the Rio das Velhas catchment, in Brazil. We use a greedy ranking algorithm to rank the potential locations to place new sensors, based on their contribution to the joint entropy of the network. Results show that the most informative locations in the catchment correspond to those areas with the highest rainfall variability and that satellite observations can be successfully employed to optimize rainfall monitoring networks.

scholarly journals Radar subpixel-scale rainfall variability and uncertainty: a lesson learned from observations of a dense rain-gauge network

2013 ◽  
Vol 10 (1) ◽  
pp. 1-32
Author(s):  
N. Peleg ◽  
M. Ben-Asher ◽  
E. Morin
Keyword(s):  
Time Scale ◽  
Temporal Variability ◽  
Variance Reduction ◽  
Sampling Error ◽  
Rainfall Variability ◽  
Total Error ◽  
Rain Gauge ◽  
Spatial And Temporal Variability ◽  
Radar Rainfall ◽  
Rain Gauges

Abstract. Hydrological models for runoff estimations and flash-flood predictions are very sensitive to rainfall's spatial and temporal variability. The increasing use of radar and satellite data in hydrological applications, due to the sparse distribution of rain gauges over most catchments worldwide, requires improving our knowledge of the uncertainties of these data. In 2011, a new super-dense network of rain gauges, containing 27 gauges covering an area of about 4 km2, was installed near Kibbutz Galed in northern Israel. This network was established for a detailed exploration of the uncertainties and errors regarding rainfall variability in remote-sensing at subpixel-scale resolution. In this paper, we present the analysis of the first year's record collected from this network and from the Shacham weather radar. The gauge–rainfall spatial correlation and uncertainty were examined along with the estimated radar error. The zero-distance correlation between rain gauges was high (0.92 on the 1-min scale) and increased as the time scale increased. The variance of the differences between radar pixel rainfall and averaged point rainfall (the variance reduction factor – VRF) was 1.6%, as measured for the 1-min scale. It was also found that at least four uniformly distributed rain stations are needed to represent the rainfall on the radar pixel scale. The radar–rain gauge error was mainly derived from radar estimation errors as the gauge sampling error contributed up to 22% to the total error. The radar rainfall estimations improved with increasing time scale and the radar-to-true rainfall ratio decreased with increasing time scale. Rainfall measurements collected with this network of rain gauges in the coming years will be used for further examination of rainfall's spatial and temporal variability.

scholarly journals Spatial Rainfall Variability in Urban Environments—High-Density Precipitation Measurements on a City-Scale

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1157 ◽  
Author(s):  
Roman Maier ◽  
Gerald Krebs ◽  
Markus Pichler ◽  
Dirk Muschalla ◽  
Günter Gruber
Keyword(s):  
Spatial Variability ◽  
Rainfall Variability ◽  
Past Research ◽  
Urban Environments ◽  
Return Periods ◽  
Rainfall Events ◽  
Rain Gauges ◽  
Temporal And Spatial Variability ◽  
One Year ◽  
Available Information

Rainfall runoff models are frequently used for design processes for urban infrastructure. The most sensitive input for these models is precipitation data. Therefore, it is crucial to account for temporal and spatial variability of rainfall events as accurately as possible to avoid misleading simulation results. This paper aims to show the significant errors that can occur by using rainfall measurement resolutions in urban environments that are too coarse. We analyzed the spatial variability of rainfall events from two years with the validated data of 22 rain gauges spread out over an urban catchment of 125 km2. By looking at the interstation correlation of the rain gauges for different classes of rainfall intensities, we found that rainfall events with low and intermediate intensities show a good interstation correlation. However, the correlation drops significantly for heavy rainfall events suggesting higher spatial variability for more intense rainstorms. Further, we analyzed the possible deviation from the spatial rainfall interpolation that uses all available rain gauges when reducing the number of rain gauges to interpolate the spatial rainfall for 24 chosen events. With these analyses we found that reducing the available information by half results in deviations of up to 25% for events with return periods shorter than one year and 45% for events with longer return periods. Assuming uniformly distributed rainfall over the entire catchment resulted in deviations of up to 75% and 125%, respectively. These findings are supported by the work of past research projects and underline the necessity of a high spatial measurement density in order to account for spatial variability of intense rainstorms.

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