Trade-off between cost and accuracy in large-scale surface water dynamic modeling

Recent efforts have led to the development of the local inertia formulation (INER) for anaccurate but still cost-efficient representation of surface water dynamics, compared to the widely used kinematic wave equation (KINE). In this study, both formulations are evaluated over the Amazon basin in terms of computational costs and accuracy in simulating streamflows and water levels through synthetic experiments and comparisons against ground-based observations. Varying time steps are considered as part of the evaluation and INER at 60-second time step is adopted as the reference for synthetic experiments. Five hybrid (HYBR) realizations are performed based on maps representing the spatial distribution of the two formulations that physically represent river reach flow dynamics within the domain. Maps have fractions of KINE varying from 35.6% to 82.8%. KINE runs show clear deterioration along the Amazon river andmain tributaries, with maximum RMSE values for streamflow and water level reaching7827m(exp 3).s(exp -1) and 1379 cm near the basins outlet. However, KINE 20 is at least 25%more efficient than INER with low model sensitivity to longer time steps. A significant improvement is achieved with HYBR, resulting in maximum RMSE values of 3.9-292 m(exp 3).s(exp -1) for streamflows and 1.1-28.5 cm for water levels, and cost reduction of 6-16%, depending on the map used. Optimal results using HYBR are obtained when the local inertia formulation is used in about one third of the Amazon basin, reducing computational costs in simulations while preserving accuracy. However, that threshold may vary when applied to different regions, according to their hydrodynamics and geomorphological characteristics

Automatic parameterization of a flow routing scheme driven by radar altimetry data: Evaluation in the Amazon basin

ISI Document Delivery No.: 129GR Times Cited: 2 Cited Reference Count: 36 Cited References: BAMBER JL, 1994, INT J REMOTE SENS, V15, P925 Birkett CM, 2000, REMOTE SENS ENVIRON, V72, P218, DOI 10.1016/S0034-4257(99)00105-4 Boone A, 1999, J APPL METEOROL, V38, P1611, DOI 10.1175/1520-0450(1999)0382.0.CO;2 Boyle DP, 2000, WATER RESOUR RES, V36, P3663, DOI 10.1029/2000WR900207 Calmant S, 2008, SURV GEOPHYS, V29, P247, DOI 10.1007/s10712-008-9051-1 Chow V. T., 1988, APPL HYDROLOGY Coe MT, 2008, HYDROL PROCESS, V22, P2542, DOI 10.1002/hyp.6850 Cogley J. G., 2003, 20031 TRENT U DEP GE Cretaux JF, 2011, ADV SPACE RES, V47, P1497, DOI 10.1016/j.asr.2011.01.004 Dadson SJ, 2010, J GEOPHYS RES-ATMOS, V115, DOI 10.1029/2010JD014474 Decharme B, 2012, CLIM DYNAM, V38, P1389, DOI 10.1007/s00382-011-1054-9 Durand M, 2010, IEEE J-STARS, V3, P20, DOI 10.1109/JSTARS.2009.2033453 Getirana A. C. 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I., 2012, HYDROL EARTH SYST SC, V9, P3203, DOI [10.5194/hessd-9-3203-2012, DOI 10.5194/HESSD-9-3203-2012] Noilhan J, 1996, GLOBAL PLANET CHANGE, V13, P145, DOI 10.1016/0921-8181(95)00043-7 Pereira-Cardenal SJ, 2011, HYDROL EARTH SYST SC, V15, P241, DOI 10.5194/hess-15-241-2011 Roux E, 2010, HYDROLOG SCI J, V55, P104, DOI 10.1080/02626660903529023 Sheffield J, 2006, J CLIMATE, V19, P3088, DOI 10.1175/JCLI3790.1 Shuttleworth W. J., 1993, HDB HYDROLOGY, P1 SOROOSHIAN S, 1983, WATER RESOUR RES, V19, P251, DOI 10.1029/WR019i001p00251 Wilson M, 2007, GEOPHYS RES LETT, V34, DOI 10.1029/2007GL030156 Yamazaki D, 2011, WATER RESOUR RES, V47, DOI 10.1029/2010WR009726 Yamazaki D, 2009, HYDROL EARTH SYST SC, V13, P2241 Yapo PO, 1998, J HYDROL, V204, P83, DOI 10.1016/S0022-1694(97)00107-8 Getirana, Augusto C. V. Boone, Aaron Yamazaki, Dai Mognard, Nelly Yamazaki, Dai/J-3029-2012 Centre National d'Etudes Spatiales (CNES) The first author thanks the Centre National d'Etudes Spatiales (CNES) for the financial support. The study benefited from data made available by Agencia Nacional de Aguas (ANA) and by the European Space Agency (ESA) under the form of Geophysical Data Records (GDRs). The multimission database of GDRs is maintained by the Centre de Topographie des Oceans et de l'Hydrosphere (CTOH) at LEGOS. The authors also thank G. Cochonneau (IRD) and M. C. Gennero (IRD) for their help in data acquisition and processing and three anonymous reviewers for their valuable comments. 2 AMER GEOPHYSICAL UNION WASHINGTON WATER RESOUR RESThis paper describes and evaluates a procedure that integrates radar altimetry data into the automatic calibration of large-scale flow routing schemes (LFRS). The Hydrological Modeling and Analysis Platform, coupled in off-line mode with the Interactions between Soil, Biosphere, and Atmosphere land surface model, is used to simulate daily surface water dynamics of the Amazon basin at a 0.25 degrees spatial resolution. The Multiobjective Complex Evolution optimization algorithm is used to optimize one parameter (subsurface runoff time delay) and other three parameter multiplier factors (Manning roughness coefficient for rivers, river width, and bankfull height) by minimizing two objective functions for the 2002 to 2006 period. Four calibration experiments are performed by combining water discharge observations and Envisat data to evaluate the potential of using radar altimetry in the automatic calibration of LFRS. One experiment is based on daily discharge observations, other combines discharge with altimetric data, and the other two ones are driven exclusively by radar altimetry data, at 16 or four virtual stations, depending on the experiment. The calibration process is validated against discharge observations at five gauging stations located on the main tributaries. This study shows the feasibility of calibrating LFRS using radar altimetry data. Results demonstrate that reasonable parameters can be obtained by using radar altimetry in an optimization procedure with competitive computational costs. However, there is evidence of equifinality among model parameters. Furthermore, the automatic calibration driven by altimetric data can reliably reproduce discharges time series, and significant improvements are noticed in simulated water level variations. Citation: Getirana, A. C. V., A. Boone, D. Yamazaki, and N. Mognard (2013), Automatic parameterization of a flow routing scheme driven by radar altimetry data: Evaluation in the Amazon basin, Water Resour. Res., 49, doi: 10.1002/wrcr.20077

Hydrological Modeling of the Peruvian-Ecuadorian Amazon Basin Using GPM-IMERG Satellite-Based Precipitation Dataset

In the last two decades, rainfall estimates provided by the Tropical Rainfall Measurement Mission (TRMM) have proven applicable in hydrological studies. The Global Precipitation Measurement (GPM) mission, which provides the new generation of rainfall estimates, is now considered a global successor to TRMM. The usefulness of GPM data in hydrological applications, however, has not yet been evaluated over the Andean and Amazonian regions. This study uses GPM data provided by the Integrated Multi-satellite Retrievals (IMERG) (productfinal run) as input to a distributed hydrological model for the Amazon Basin of Peru and Ecuador for a 16-month period (from March 2014 to June 2015) when all datasets are available. TRMM products (TMPA V7, TMPA RT datasets) and a gridded precipitation dataset processed from observed rainfall are used for comparison. The results indicate that precipitation data derived from GPM-IMERG correspond more closely to TMPA V7 than TMPA RT datasets, but both GPM-IMERG and TMPA V7 precipitation data tend to overestimate, compared to observed rainfall (by 11.1 and 15.7 , respectively). In general, GPM-IMERG, TMPA V7 and TMPA RT correlate with observed rainfall, with a similar number of rain events correctly detected (20). Statistical analysis of modeled streamflows indicates that GPM-IMERG is as useful as TMPA V7 or TMPA RT datasets in southern regions (Ucayali basin). GPM-IMERG, TMPA V7 and TMPA RT do not properly simulate streamflows in northern regions (Maran and Napo basins), probably because of the lack of adequate rainfall estimates in northern Peru and the Ecuadorian Amazon

Rivers and Floodplains as Key Components of Global Terrestrial Water Storage Variability

This study quantifies the contribution of rivers and floodplains to terrestrial water storage (TWS) variability. We use stateoftheart models to simulate land surface processes and river dynamics and to separate TWS into its main components. Based on a proposed impact index, we show that surface water storage (SWS) contributes 8% of TWS variability globally, but that contribution differs widely among climate zones. Changes in SWS are a principal component of TWS variability in the tropics, where major rivers flow over arid regions and at high latitudes. SWS accounts for ~2227% of TWS variability in both the Amazon and Nile Basins. Changes in SWS are negligible in the Western U.S., Northern Africa, Middle East, and central Asia. Based on comparisons with Gravity Recovery and Climate Experimentbased TWS, we conclude that accounting for SWS improves simulated TWS in most of South America, Africa, and Southern Asia, confirming that SWS is a key component of TWS variability

Monitoring River Basin Development and Variation in Water Resources in Transboundary Imjin River in North and South Korea Using Remote Sensing

This paper presents methods of monitoring river basin development and water variability for the transboundary river in North and South Korea. River basin development, such as dams and water infrastructure in transboundary rivers, can be a potential factor of tensions between upstream and downstream countries since dams constructed upstream can adversely affect downstream riparians. However, because most of the information related to North Korea has been limited to the public, the information about dams constructed and their locations were inaccurate in many previous studies. In addition, water resources in transboundary rivers can be exploited as a political tool. Specifically, due to the unexpected water release from the Hwanggang Dam, upstream of the transboundary Imjin River in North and South Korea, six South Koreans died on 6 September 2009. The Imjin River can be used as a political tool by North Korea, and seven events were reported as water conflicts in the Imjin River from 2001 to 2016. In this paper, firstly, we have updated the information about the dams constructed over the Imjin River in North Korea using multi-temporal images with a high spatial resolution (15-30 cm) obtained from Google Earth. Secondly, we analyzed inter- and intra-water variability over the Hwanggang Reservoir using open-source images obtained from the Global Surface Water Explorer. We found a considerable change in water surface variability before and after 2008, which might result from the construction of the Hwanggang Dam. Thirdly, in order to further investigate intra-annual water variability, we present a method monitoring water storage changes of the Hwanggang Reservoir using the area-elevation curve (AEC), which was derived from multi-sensor Synthetic Aperture Radar (SAR) images (Sentinel-1A and -1B) and the Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM). Since many previous studies for estimating water storage change have depended on satellite altimetry dataset and optical images for deriving AEC, the method adopted in this study is the only application for such inaccessible areas since no altimetry ground track exists for the Hwanggang Reservoir and because clouds can block the study area for wet seasons. Moreover, this study has newly proven that unexpected water release can occur in dry seasons because the water storage in the Hwanggang Reservoir can be high enough to conduct a release that can be used as a geopolitical tool. Using our method, potential risks can be mitigated, not in response to a water release, but based on pre-event water storage changes in the Hwanggang Reservoir

Uncertainties in Evapotranspiration Estimates over West Africa

An evapotranspiration (ET) ensemble composed of 36 land surface model (LSM) experiments and four diagnostic datasets (GLEAM, ALEXI, MOD16, and FLUXNET) is used to investigate uncertainties in ET estimate over five climate regions in West Africa. Diagnostic ET datasets show lower uncertainty estimates and smaller seasonal variations than the LSM-based ET values, particularly in the humid climate regions. Overall, the impact of the choice of LSMs and meteorological forcing datasets on the modeled ET rates increases from north to south. The LSM formulations and parameters have the largest impact on ET in humid regions, contributing to 90% of the ET uncertainty estimates. Precipitation contributes to the ET uncertainty primarily in arid regions. The LSM-based ET estimates are sensitive to the uncertainty of net radiation in arid region and precipitation in humid region. This study serves as support for better determining water availability for agriculture and livelihoods in Africa with earth observations and land surface models

Assimilation of MODIS Snow Cover Fraction Observations into the NASA Catchment Land Surface Model

The NASA Catchment land surface model (CLSM) is the land model component used for the Modern-Era Retrospective Analysis for Research and Applications (MERRA). Here, the CLSM versions of MERRA and MERRA-Land are evaluated using snow cover fraction (SCF) observations from the Moderate Resolution Imaging Spectroradiometer (MODIS). Moreover, a computationally-efficient empirical scheme is designed to improve CLSM estimates of SCF, snow depth, and snow water equivalent (SWE) through the assimilation of MODIS SCF observations. Results show that data assimilation (DA) improved SCF estimates compared to the open-loop model without assimilation (OL), especially in areas with ephemeral snow cover and mountainous regions. A comparison of the SCF estimates from DA against snow cover estimates from the NOAA Interactive Multisensor Snow and Ice Mapping System showed an improvement in the probability of detection of up to 28% and a reduction in false alarms by up to 6% (relative to OL). A comparison of the model snow depth estimates against Canadian Meteorological Centre analyses showed that DA successfully improved the model seasonal bias from 0.017 m for OL to 0.007 m for DA, although there was no significant change in root-mean-square differences (RMSD) (0.095 m for OL, 0.093 m for DA). The time-average of the spatial correlation coefficient also improved from 0.61 for OL to 0.63 for DA. A comparison against in situ SWE measurements also showed improvements from assimilation. The correlation increased from 0.44 for OL to 0.49 for DA, the bias improved from 0.111 m for OL to 0.100 m for DA, and the RMSD decreased from 0.186 m for OL to 0.180 m for DA

Assessment of three long-term gridded climate products for hydro-climatic simulations in tropical river basins

10.3390/w9030229Water (Switzerland)9322

Matriz de covariância corrigida para os modelos não-lineares da família exponencial

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia de ProduçãoOs modelos nao-lineares da familia exponencial e uma extensao dos modelos lineares generalizados, permitindo que o preditor da media seja nao-linear. Esses modelos, por serem menos restritivos, tem sido utilizados para modelar sistemas produtivos como mais uma ferramenta na tomada de decisao. Usualmente, os parametros desses modelos sao estimados pelo metodo de maxima verossimilhanca, que tem propriedades assintoticas de O(n-1), onde n e o tamanho da amostra. Portanto, para tamanhos de amostras pequenos, pode haver erros consideraveis, nas inferencias. Essa Tese tem como objetivo obter uma expressao analitica para a matriz de covariancia de segunda ordem do estimador de maxima verossimilhanca para os parametros dos modelos nao-lineares da familia exponencial que contribuira no procedimento de inferencia da verossimilhanca, quando o tamanho da amostra e pequeno. Esse estimador, que nada mais e do que uma correcao do que vem sendo utilizado, tem propriedades assint´oticas de O(n-2). A metodologia adotada consistiu em obter os cumulantes desses modelos e substitui-los na funcao geratriz dos cumulantes, que, pela propriedade de invariancia sob permutacao de indices nos modelos nao-lineares da familia exponencial, pode ser simplificada e expressa em termos de matrizes. A expressao obtida e de facil implementacao computacional, uma vez que consiste de operacoes com matrizes. O estimador de segunda ordem da matriz de covariancia foi avaliado por um estudo de simulacao que mostrou que esse e indispensavel para amostras de tamanho pequeno a moderado. Para ilustrar o uso da tecnica proposta, uma aplicacoes na avaliacao da qualidade do papel cujo modelo que descreve a variavel resposta grau de refino das fibras e log-linear e componente aleatoria gama. Nessa aplicacao evidenciou-se a necessidade dos estimadores de O(n-2)

Análise aguda dos marcadores mecânicos da fadiga em diferentes métodos de treino no powerlifting paralímpico

Introduction: In Brazilian society and in the world, a great search for high performance sports is noticeable. Within this perspective, the Paralympic modalities have been gaining prominence. The growing number of Paralympic athletes with each cycle of the games only increases, great records were broken at the London 2012 Paralympics, from broadcasts, audiences, public as well as in sports performance. The benefits of sports practice for people with disabilities are already well disseminated in society, the training routine promotes numerous benefits as well as some degree of risk of injury. Objective: The objective of this study was to evaluate the neuromuscular indicators of fatigue in two different training methods: isoinertial and eccentric in the adapted bench press in Paralympic powerlifting athletes. Methods: Eleven male Paralympic powerlifting athletes (age 31.54±9.72; body weight 73.63±17.55; 1RM 121.63±40.94) were evaluated to measure neuromuscular fatigue. Fatigue was measured in five moments through the average propulsive velocity - MPV, Pre-intervention (average of the MPV of three repetitions at 45% of the 1RM), intervention (average of the MPV of the five repetitions during five sets at a load of 80% of the 1RM for TRAD and 110%-80% of 1RM for ECC), post-intervention (average of three repetitions MPV at 45% of 1RM) 24h after the training session (average of three repetitions MPV at 45% of 1RM) and 48h after the training session (average of the MPV of three repetitions at 45% of the 1RM). For the intervention, 5 sets of 5 repetitions were used for both workouts. Results: Traditional training did not present neuromuscular fatigue in any of the analyzed moments. In relation to eccentric training, there is a significant reduction in PMV pre and post training: ECC (0.85 m/s ± 0.21, 95% CI 0.70-0.99; vs. 0.72 m/s ± 0.20, 95% CI 0.59-0.86, respectively, p=0.002, F(1,10)=3,310, η2p=0,249 - average effect). There was also a difference between TRAD and ECC training after intervention (0.87 m/s ± 0.22, 95%CI 0.72-1.02 vs. 0.72 ± 0.20, 95%CI 0.59-0.86 p=0.042, F(3.30)=10.190, η2p =0.505 - very high effect). During the training sets, the loss of MPV in set “1” was significant between traditional and eccentric training (15.46 m/s ± 3.64%, 95%CI 13.02-17.90 vs. 27.55 m/s ± 3.64%, 95%CI 13.02-17.90 vs. 12.21%, 95%CI 19.34-35.76, respectively, p=0.003) and in the series "3" between the TRAD (17.12 m/s ±6.78%, 95%CI 12.56-21 .67) and ECC (25.72 m/s ±10.38%, 95%CI 18.75-32.69, p=0.041). In both series, F(1,10)=22,762, η2p=0,695 (Very high effect). Conclusion: after the observed results, Coaches and Paralympic Powerlifting competitors should be cautious in using only the VMP as an indicator of neuromuscular fatigue for strength competitors. because when performing five sets of five repetitions at 80% of the 1 RM, neuromuscular fatigue was not observed.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPESIntrodução: Na sociedade Brasileira e no mundo, é perceptível uma grande busca pelo esporte de alto rendimento. Dentro desta perspectiva, as modalidades paralímpicas vêm ganhando destaques. O crescente número de atletas paralímpicos a cada ciclo dos jogos só aumenta, grandes recordes foram quebrados na paralimpíada de Londres 2012, desde transmissões, audiências, público como também em performance esportiva. Os benefícios da pratica esportiva para pessoas com deficiências já são bem disseminados na sociedade, a rotina de treino promove inúmeros benefícios como também algum grau de risco de lesões. Objetivo: O objetivo deste estudo foi avaliar os indicadores neuromusculares da fadiga em dois diferentes métodos de treino: isoinerciais e excêntrico no supino reto adaptado em atletas de powerlifting paralímpicos. Métodos: Onze atletas homens de powerlifting paralímpico (idade 31,54±9,72; peso corporal 73,63±17,55; 1RM 121,63±40,94) foram avaliados para mensurar a fadiga neuromuscular. A fadiga foi mensurada em cinco momentos através da velocidade média propulsiva - VMP, Pré-intervenção (média da VMP de três repetições a 45% do 1RM), intervenção (média da VMP das cinco repetições durante cinco séries a uma carga de 80% do 1RM para TRAD e 110%-80% do 1RM para ECC), pós-intervenção (média da VMP de três repetições a 45% do 1RM) 24h após a sessão de treino (média da VMP de três repetições a 45% do 1RM) e 48h após a sessão de treino (média da VMP de três repetições a 45% do 1RM). Para a intervenção, foram utilizados 5 séries de 5 repetições para ambos os treinos. Resultados: O treinamento tradicional não apresentou fadiga neuromuscular em nenhum dos momentos analisados. Em relação ao treinamento excêntrico, observa-se redução significativa da VMP pré e pós treino: ECC (0.85 m/s ± 0.21, IC95% 0.70-0.99; vs. 0.72 m/s ± 0.20, IC95% 0.59- 0.86, respectivamente, p=0.002, F(1,10)=3.310, η2p=0.249 - efeito médio). Foi verificada também diferença entre os treinos TRAD e ECC pós intervenção (0.87 m/s ± 0.22, IC95% 0.72-1.02 vs. 0.72 ± 0.20, IC95% 0.59-0.86 p=0.042, F(3,30)=10.190, η2p=0.505 - efeito muito alto). Durante as séries de treinamento, a perda da VMP na série “1” foi significativa entre os treinos tradicional e excêntrico (15.46 m/s ± 3.64%, IC95% 13,02-17,90 vs. 27,55 m/s ±12,21%, IC95% 19,34-35,76, respectivamente, p=0.003) e na série “3” entre o TRAD (17,12 m/s ±6,78%, IC95% 12,56-21,67) e ECC (25,72 m/s ±10,38%, IC95% 18,75-32,69, p=0.041). Nas duas séries, o F(1,10)=22.762, η2p=0.695 (Efeito muito alto). Conclusão: após os resultados observados, Técnicos e competidores de Powerlifting Paralímpico devem ter cautela em utilizar apenas a VMP como indicador de fadiga neuromuscular para competidores de força. pois ao realizar cinco series de cinco repetições a 80% do 1 RM, não foi observado fadiga neuromuscular.São Cristóvã